#include "game/world_packets.hpp"
#include "game/packet_parsers.hpp"
#include "game/opcodes.hpp"
#include "game/character.hpp"
#include "auth/crypto.hpp"
#include "core/logger.hpp"
#include <algorithm>
#include <array>
#include <cctype>
#include <cmath>
#include <cstring>
#include <sstream>
#include <iomanip>
#include <zlib.h>

namespace {

inline uint32_t bswap32(uint32_t v) {
    return ((v & 0xFF000000u) >> 24) | ((v & 0x00FF0000u) >> 8)
         | ((v & 0x0000FF00u) << 8)  | ((v & 0x000000FFu) << 24);
}

inline uint16_t bswap16(uint16_t v) {
    return static_cast<uint16_t>(((v & 0xFF00u) >> 8) | ((v & 0x00FFu) << 8));
}

} // anonymous namespace

namespace wowee {
namespace game {

bool SpellGoParser::parse(network::Packet& packet, SpellGoData& data) {
    // Always reset output to avoid stale targets when callers reuse buffers.
    data = SpellGoData{};

    // Packed GUIDs are variable-length, so only require the smallest possible
    // shape up front: 2 GUID masks + fixed fields through hitCount.
    if (!packet.hasRemaining(16)) return false;

    size_t startPos = packet.getReadPos();
    if (!packet.hasFullPackedGuid()) {
        return false;
    }
    data.casterGuid = packet.readPackedGuid();
    if (!packet.hasFullPackedGuid()) {
        packet.setReadPos(startPos);
        return false;
    }
    data.casterUnit = packet.readPackedGuid();

    // Validate remaining fixed fields up to hitCount/missCount
    if (!packet.hasRemaining(14)) { // castCount(1) + spellId(4) + castFlags(4) + timestamp(4) + hitCount(1)
        packet.setReadPos(startPos);
        return false;
    }

    data.castCount = packet.readUInt8();
    data.spellId = packet.readUInt32();
    data.castFlags = packet.readUInt32();
    // Timestamp in 3.3.5a
    packet.readUInt32();

    const uint8_t rawHitCount = packet.readUInt8();
    if (rawHitCount > 128) {
        LOG_WARNING("Spell go: hitCount capped (requested=", static_cast<int>(rawHitCount), ")");
    }
    const uint8_t storedHitLimit = std::min<uint8_t>(rawHitCount, 128);

    bool truncatedTargets = false;

    data.hitTargets.reserve(storedHitLimit);
    for (uint16_t i = 0; i < rawHitCount; ++i) {
        // WotLK 3.3.5a hit targets are full uint64 GUIDs (not PackedGuid).
        if (!packet.hasRemaining(8)) {
            LOG_WARNING("Spell go: truncated hit targets at index ", i, "/", static_cast<int>(rawHitCount));
            truncatedTargets = true;
            break;
        }
        const uint64_t targetGuid = packet.readUInt64();
        if (i < storedHitLimit) {
            data.hitTargets.push_back(targetGuid);
        }
    }
    if (truncatedTargets) {
        packet.setReadPos(startPos);
        return false;
    }
    data.hitCount = static_cast<uint8_t>(data.hitTargets.size());

    // missCount is mandatory in SMSG_SPELL_GO. Missing byte means truncation.
    if (!packet.hasRemaining(1)) {
        LOG_WARNING("Spell go: missing missCount after hit target list");
        packet.setReadPos(startPos);
        return false;
    }

    const size_t missCountPos = packet.getReadPos();
    const uint8_t rawMissCount = packet.readUInt8();
    if (rawMissCount > 20) {
        // Likely offset error — dump context bytes for diagnostics.
        const auto& raw = packet.getData();
        std::string hexCtx;
        size_t dumpStart = (missCountPos >= 8) ? missCountPos - 8 : startPos;
        size_t dumpEnd = std::min(missCountPos + 16, raw.size());
        for (size_t i = dumpStart; i < dumpEnd; ++i) {
            char buf[4];
            std::snprintf(buf, sizeof(buf), "%02x ", raw[i]);
            hexCtx += buf;
            if (i == missCountPos - 1) hexCtx += "[";
            if (i == missCountPos) hexCtx += "] ";
        }
        LOG_WARNING("Spell go: suspect missCount=", static_cast<int>(rawMissCount),
                    " spell=", data.spellId, " hits=", static_cast<int>(data.hitCount),
                    " castFlags=0x", std::hex, data.castFlags, std::dec,
                    " missCountPos=", missCountPos, " pktSize=", packet.getSize(),
                    " ctx=", hexCtx);
    }
    if (rawMissCount > 128) {
        LOG_WARNING("Spell go: missCount capped (requested=", static_cast<int>(rawMissCount),
                    ") spell=", data.spellId, " hits=", static_cast<int>(data.hitCount),
                    " remaining=", packet.getRemainingSize());
    }
    const uint8_t storedMissLimit = std::min<uint8_t>(rawMissCount, 128);

    data.missTargets.reserve(storedMissLimit);
    for (uint16_t i = 0; i < rawMissCount; ++i) {
        // WotLK 3.3.5a miss targets are full uint64 GUIDs + uint8 missType.
        // REFLECT additionally appends uint8 reflectResult.
        if (!packet.hasRemaining(9)) { // 8 GUID + 1 missType
            LOG_WARNING("Spell go: truncated miss targets at index ", i, "/", static_cast<int>(rawMissCount),
                        " spell=", data.spellId, " hits=", static_cast<int>(data.hitCount));
            truncatedTargets = true;
            break;
        }
        SpellGoMissEntry m;
        m.targetGuid = packet.readUInt64();
        m.missType = packet.readUInt8();
        if (m.missType == 11) { // SPELL_MISS_REFLECT
            if (!packet.hasRemaining(1)) {
                LOG_WARNING("Spell go: truncated reflect payload at miss index ", i, "/", static_cast<int>(rawMissCount));
                truncatedTargets = true;
                break;
            }
            (void)packet.readUInt8(); // reflectResult
        }
        if (i < storedMissLimit) {
            data.missTargets.push_back(m);
        }
    }
    data.missCount = static_cast<uint8_t>(data.missTargets.size());

    // If miss targets were truncated, salvage the successfully-parsed hit data
    // rather than discarding the entire spell. The server already applied effects;
    // we just need the hit list for UI feedback (combat text, health bars).
    if (truncatedTargets) {
        LOG_DEBUG("Spell go: salvaging ", static_cast<int>(data.hitCount), " hits despite miss truncation");
        packet.skipAll(); // consume remaining bytes
        return true;
    }

    // WotLK 3.3.5a SpellCastTargets — consume ALL target payload bytes so that
    // any trailing fields after the target section are not misaligned for
    // ground-targeted or AoE spells.  Same layout as SpellStartParser.
    if (packet.hasData()) {
        if (packet.hasRemaining(4)) {
            uint32_t targetFlags = packet.readUInt32();

            auto readPackedTarget = [&](uint64_t* out) -> bool {
                if (!packet.hasFullPackedGuid()) return false;
                uint64_t g = packet.readPackedGuid();
                if (out) *out = g;
                return true;
            };
            auto skipPackedAndFloats3 = [&]() -> bool {
                if (!packet.hasFullPackedGuid()) return false;
                packet.readPackedGuid(); // transport GUID
                if (!packet.hasRemaining(12)) return false;
                packet.readFloat(); packet.readFloat(); packet.readFloat();
                return true;
            };

            // UNIT/UNIT_MINIPET/CORPSE_ALLY/GAMEOBJECT share one object target GUID
            if (targetFlags & (0x0002u | 0x0004u | 0x0400u | 0x0800u)) {
                readPackedTarget(&data.targetGuid);
            }
            // ITEM/TRADE_ITEM share one item target GUID
            if (targetFlags & (0x0010u | 0x0100u)) {
                readPackedTarget(nullptr);
            }
            // SOURCE_LOCATION: PackedGuid (transport) + float x,y,z
            if (targetFlags & 0x0020u) {
                skipPackedAndFloats3();
            }
            // DEST_LOCATION: PackedGuid (transport) + float x,y,z
            if (targetFlags & 0x0040u) {
                skipPackedAndFloats3();
            }
            // STRING: null-terminated
            if (targetFlags & 0x0200u) {
                while (packet.hasData() && packet.readUInt8() != 0) {}
            }
        }
    }

    LOG_DEBUG("Spell go: spell=", data.spellId, " hits=", static_cast<int>(data.hitCount),
             " misses=", static_cast<int>(data.missCount));
    return true;
}

bool AuraUpdateParser::parse(network::Packet& packet, AuraUpdateData& data, bool isAll) {
    // Validation: packed GUID (1-8 bytes minimum for reading)
    if (!packet.hasRemaining(1)) return false;

    data.guid = packet.readPackedGuid();

    // Cap number of aura entries to prevent unbounded loop DoS
    uint32_t maxAuras = isAll ? 512 : 1;
    uint32_t auraCount = 0;

    while (packet.hasData() && auraCount < maxAuras) {
        // Validate we can read slot (1) + spellId (4) = 5 bytes minimum
        if (!packet.hasRemaining(5)) {
            LOG_DEBUG("Aura update: truncated entry at position ", auraCount);
            break;
        }

        uint8_t slot = packet.readUInt8();
        uint32_t spellId = packet.readUInt32();
        auraCount++;

        AuraSlot aura;
        if (spellId != 0) {
            aura.spellId = spellId;

            // Validate flags + level + charges (3 bytes)
            if (!packet.hasRemaining(3)) {
                LOG_WARNING("Aura update: truncated flags/level/charges at entry ", auraCount);
                aura.flags = 0;
                aura.level = 0;
                aura.charges = 0;
            } else {
                aura.flags = packet.readUInt8();
                aura.level = packet.readUInt8();
                aura.charges = packet.readUInt8();
            }

            if (!(aura.flags & 0x08)) { // NOT_CASTER flag
                // Validate space for packed GUID read (minimum 1 byte)
                if (!packet.hasRemaining(1)) {
                    aura.casterGuid = 0;
                } else {
                    aura.casterGuid = packet.readPackedGuid();
                }
            }

            if (aura.flags & 0x20) { // DURATION - need 8 bytes (two uint32s)
                if (!packet.hasRemaining(8)) {
                    LOG_WARNING("Aura update: truncated duration fields at entry ", auraCount);
                    aura.maxDurationMs = 0;
                    aura.durationMs = 0;
                } else {
                    aura.maxDurationMs = static_cast<int32_t>(packet.readUInt32());
                    aura.durationMs = static_cast<int32_t>(packet.readUInt32());
                }
            }

            if (aura.flags & 0x40) { // EFFECT_AMOUNTS
                // Only read amounts for active effect indices (flags 0x01, 0x02, 0x04)
                for (int i = 0; i < 3; ++i) {
                    if (aura.flags & (1 << i)) {
                        if (packet.hasRemaining(4)) {
                            packet.readUInt32();
                        } else {
                            LOG_WARNING("Aura update: truncated effect amount ", i, " at entry ", auraCount);
                            break;
                        }
                    }
                }
            }
        }

        data.updates.push_back({slot, aura});

        // For single update, only one entry
        if (!isAll) break;
    }

    if (auraCount >= maxAuras && packet.hasData()) {
        LOG_WARNING("Aura update: capped at ", maxAuras, " entries, remaining data ignored");
    }

    LOG_DEBUG("Aura update for 0x", std::hex, data.guid, std::dec,
              ": ", data.updates.size(), " slots");
    return true;
}

bool SpellCooldownParser::parse(network::Packet& packet, SpellCooldownData& data) {
    // Upfront validation: guid(8) + flags(1) = 9 bytes minimum
    if (!packet.hasRemaining(9)) return false;

    data.guid = packet.readUInt64();
    data.flags = packet.readUInt8();

    // Cap cooldown entries to prevent unbounded memory allocation (each entry is 8 bytes)
    uint32_t maxCooldowns = 512;
    uint32_t cooldownCount = 0;

    while (packet.hasRemaining(8) && cooldownCount < maxCooldowns) {
        uint32_t spellId = packet.readUInt32();
        uint32_t cooldownMs = packet.readUInt32();
        data.cooldowns.push_back({spellId, cooldownMs});
        cooldownCount++;
    }

    if (cooldownCount >= maxCooldowns && packet.hasRemaining(8)) {
        LOG_WARNING("Spell cooldowns: capped at ", maxCooldowns, " entries, remaining data ignored");
    }

    LOG_DEBUG("Spell cooldowns: ", data.cooldowns.size(), " entries");
    return true;
}

// ============================================================
// Group/Party System
// ============================================================

network::Packet GroupInvitePacket::build(const std::string& playerName) {
    network::Packet packet(wireOpcode(Opcode::CMSG_GROUP_INVITE));
    packet.writeString(playerName);
    packet.writeUInt32(0); // unused
    LOG_DEBUG("Built CMSG_GROUP_INVITE: ", playerName);
    return packet;
}

bool GroupInviteResponseParser::parse(network::Packet& packet, GroupInviteResponseData& data) {
    // Validate minimum packet size: canAccept(1)
    if (!packet.hasRemaining(1)) {
        LOG_WARNING("SMSG_GROUP_INVITE: packet too small (", packet.getSize(), " bytes)");
        return false;
    }

    data.canAccept = packet.readUInt8();
    // Note: inviterName is a string, which is always safe to read even if empty
    data.inviterName = packet.readString();
    LOG_INFO("Group invite from: ", data.inviterName, " (canAccept=", static_cast<int>(data.canAccept), ")");
    return true;
}

network::Packet GroupAcceptPacket::build() {
    network::Packet packet(wireOpcode(Opcode::CMSG_GROUP_ACCEPT));
    packet.writeUInt32(0); // unused in 3.3.5a
    return packet;
}

network::Packet GroupDeclinePacket::build() {
    network::Packet packet(wireOpcode(Opcode::CMSG_GROUP_DECLINE));
    return packet;
}

bool GroupListParser::parse(network::Packet& packet, GroupListData& data, bool hasRoles) {
    auto rem = [&]() { return packet.getRemainingSize(); };

    if (rem() < 3) return false;
    data.groupType = packet.readUInt8();
    data.subGroup  = packet.readUInt8();
    data.flags     = packet.readUInt8();

    // WotLK 3.3.5a added a roles byte (tank/healer/dps) for the dungeon finder.
    // Classic 1.12 and TBC 2.4.3 do not have this byte.
    if (hasRoles) {
        if (rem() < 1) return false;
        data.roles = packet.readUInt8();
    } else {
        data.roles = 0;
    }

    // WotLK: LFG data gated by groupType bit 0x04 (LFD group type)
    if (hasRoles && (data.groupType & 0x04)) {
        if (rem() < 5) return false;
        packet.readUInt8();  // lfg state
        packet.readUInt32(); // lfg entry
        // WotLK 3.3.5a may or may not send the lfg flags byte — read it only if present
        if (rem() >= 13) { // enough for lfgFlags(1)+groupGuid(8)+counter(4)
            packet.readUInt8(); // lfg flags
        }
    }

    if (rem() < 12) return false;
    packet.readUInt64(); // group GUID
    packet.readUInt32(); // update counter

    if (rem() < 4) return false;
    data.memberCount = packet.readUInt32();
    if (data.memberCount > 40) {
        LOG_WARNING("GroupListParser: implausible memberCount=", data.memberCount, ", clamping");
        data.memberCount = 40;
    }
    data.members.reserve(data.memberCount);

    for (uint32_t i = 0; i < data.memberCount; ++i) {
        if (rem() == 0) break;
        GroupMember member;
        member.name     = packet.readString();
        if (rem() < 8) break;
        member.guid     = packet.readUInt64();
        if (rem() < 3) break;
        member.isOnline = packet.readUInt8();
        member.subGroup = packet.readUInt8();
        member.flags    = packet.readUInt8();
        // WotLK added per-member roles byte; Classic/TBC do not have it.
        if (hasRoles) {
            if (rem() < 1) break;
            member.roles = packet.readUInt8();
        } else {
            member.roles = 0;
        }
        data.members.push_back(member);
    }

    if (rem() < 8) {
        LOG_INFO("Group list: ", data.memberCount, " members (no leader GUID in packet)");
        return true;
    }
    data.leaderGuid = packet.readUInt64();

    if (data.memberCount > 0 && rem() >= 10) {
        data.lootMethod   = packet.readUInt8();
        data.looterGuid   = packet.readUInt64();
        data.lootThreshold = packet.readUInt8();
        // Dungeon difficulty (heroic/normal) — Classic doesn't send this; TBC/WotLK do
        if (rem() >= 1) data.difficultyId     = packet.readUInt8();
        // Raid difficulty — WotLK only
        if (rem() >= 1) data.raidDifficultyId = packet.readUInt8();
        // Extra byte in some 3.3.5a builds
        if (hasRoles && rem() >= 1) packet.readUInt8();
    }

    LOG_INFO("Group list: ", data.memberCount, " members, leader=0x",
             std::hex, data.leaderGuid, std::dec);
    return true;
}

bool PartyCommandResultParser::parse(network::Packet& packet, PartyCommandResultData& data) {
    // Upfront validation: command(4) + name(var) + result(4) = 8 bytes minimum (plus name string)
    if (!packet.hasRemaining(8)) return false;

    data.command = static_cast<PartyCommand>(packet.readUInt32());
    data.name = packet.readString();

    // Validate result field exists (4 bytes)
    if (!packet.hasRemaining(4)) {
        data.result = static_cast<PartyResult>(0);
        return true; // Partial read is acceptable
    }

    data.result = static_cast<PartyResult>(packet.readUInt32());
    LOG_DEBUG("Party command result: ", static_cast<int>(data.result));
    return true;
}

bool GroupDeclineResponseParser::parse(network::Packet& packet, GroupDeclineData& data) {
    // Upfront validation: playerName is a CString (minimum 1 null terminator)
    if (!packet.hasRemaining(1)) return false;

    data.playerName = packet.readString();
    LOG_INFO("Group decline from: ", data.playerName);
    return true;
}

// ============================================================
// Loot System
// ============================================================

network::Packet LootPacket::build(uint64_t targetGuid) {
    network::Packet packet(wireOpcode(Opcode::CMSG_LOOT));
    packet.writeUInt64(targetGuid);
    LOG_DEBUG("Built CMSG_LOOT: target=0x", std::hex, targetGuid, std::dec);
    return packet;
}

network::Packet AutostoreLootItemPacket::build(uint8_t slotIndex) {
    network::Packet packet(wireOpcode(Opcode::CMSG_AUTOSTORE_LOOT_ITEM));
    packet.writeUInt8(slotIndex);
    return packet;
}

network::Packet UseItemPacket::build(uint8_t bagIndex, uint8_t slotIndex, uint64_t itemGuid, uint32_t spellId) {
    network::Packet packet(wireOpcode(Opcode::CMSG_USE_ITEM));
    packet.writeUInt8(bagIndex);
    packet.writeUInt8(slotIndex);
    packet.writeUInt8(0);  // cast count
    packet.writeUInt32(spellId); // spell id from item data
    packet.writeUInt64(itemGuid); // full 8-byte GUID
    packet.writeUInt32(0); // glyph index
    packet.writeUInt8(0);  // cast flags
    // SpellCastTargets: self
    packet.writeUInt32(0x00);
    return packet;
}

network::Packet OpenItemPacket::build(uint8_t bagIndex, uint8_t slotIndex) {
    network::Packet packet(wireOpcode(Opcode::CMSG_OPEN_ITEM));
    packet.writeUInt8(bagIndex);
    packet.writeUInt8(slotIndex);
    return packet;
}

network::Packet AutoEquipItemPacket::build(uint8_t srcBag, uint8_t srcSlot) {
    network::Packet packet(wireOpcode(Opcode::CMSG_AUTOEQUIP_ITEM));
    packet.writeUInt8(srcBag);
    packet.writeUInt8(srcSlot);
    return packet;
}

network::Packet SwapItemPacket::build(uint8_t dstBag, uint8_t dstSlot, uint8_t srcBag, uint8_t srcSlot) {
    network::Packet packet(wireOpcode(Opcode::CMSG_SWAP_ITEM));
    packet.writeUInt8(dstBag);
    packet.writeUInt8(dstSlot);
    packet.writeUInt8(srcBag);
    packet.writeUInt8(srcSlot);
    return packet;
}

network::Packet SplitItemPacket::build(uint8_t srcBag, uint8_t srcSlot,
                                       uint8_t dstBag, uint8_t dstSlot, uint8_t count) {
    network::Packet packet(wireOpcode(Opcode::CMSG_SPLIT_ITEM));
    packet.writeUInt8(srcBag);
    packet.writeUInt8(srcSlot);
    packet.writeUInt8(dstBag);
    packet.writeUInt8(dstSlot);
    packet.writeUInt8(count);
    return packet;
}

network::Packet SwapInvItemPacket::build(uint8_t srcSlot, uint8_t dstSlot) {
    network::Packet packet(wireOpcode(Opcode::CMSG_SWAP_INV_ITEM));
    packet.writeUInt8(srcSlot);
    packet.writeUInt8(dstSlot);
    return packet;
}

network::Packet LootMoneyPacket::build() {
    network::Packet packet(wireOpcode(Opcode::CMSG_LOOT_MONEY));
    return packet;
}

network::Packet LootReleasePacket::build(uint64_t lootGuid) {
    network::Packet packet(wireOpcode(Opcode::CMSG_LOOT_RELEASE));
    packet.writeUInt64(lootGuid);
    return packet;
}

bool LootResponseParser::parse(network::Packet& packet, LootResponseData& data, bool isWotlkFormat) {
    data = LootResponseData{};
    size_t avail = packet.getRemainingSize();

    // Minimum is guid(8)+lootType(1) = 9 bytes.  Servers send a short packet with
    // lootType=0 (LOOT_NONE) when loot is unavailable (e.g. chest not yet opened,
    // needs a key, or another player is looting).  We treat this as an empty-loot
    // signal and return false so the caller knows not to open the loot window.
    if (avail < 9) {
        LOG_WARNING("LootResponseParser: packet too short (", avail, " bytes)");
        return false;
    }

    data.lootGuid = packet.readUInt64();
    data.lootType = packet.readUInt8();

    // Short failure packet — no gold/item data follows.
    avail = packet.getRemainingSize();
    if (avail < 5) {
        LOG_DEBUG("LootResponseParser: lootType=", static_cast<int>(data.lootType), " (empty/failure response)");
        return false;
    }

    data.gold = packet.readUInt32();
    uint8_t itemCount = packet.readUInt8();

    // Per-item wire size is 22 bytes across all expansions:
    //   slot(1)+itemId(4)+count(4)+displayInfo(4)+randSuffix(4)+randProp(4)+slotType(1) = 22
    constexpr size_t kItemSize = 22u;

    auto parseLootItemList = [&](uint8_t listCount, bool markQuestItems) -> bool {
        for (uint8_t i = 0; i < listCount; ++i) {
            size_t remaining = packet.getRemainingSize();
            if (remaining < kItemSize) {
                return false;
            }

            LootItem item;
            item.slotIndex        = packet.readUInt8();
            item.itemId           = packet.readUInt32();
            item.count            = packet.readUInt32();
            item.displayInfoId    = packet.readUInt32();
            item.randomSuffix     = packet.readUInt32();
            item.randomPropertyId = packet.readUInt32();
            item.lootSlotType     = packet.readUInt8();
            item.isQuestItem      = markQuestItems;
            data.items.push_back(item);
        }
        return true;
    };

    data.items.reserve(itemCount);
    if (!parseLootItemList(itemCount, false)) {
        LOG_WARNING("LootResponseParser: truncated regular item list");
        return false;
    }

    // Quest item section only present in WotLK 3.3.5a
    uint8_t questItemCount = 0;
    if (isWotlkFormat && packet.hasRemaining(1)) {
        questItemCount = packet.readUInt8();
        data.items.reserve(data.items.size() + questItemCount);
        if (!parseLootItemList(questItemCount, true)) {
            LOG_WARNING("LootResponseParser: truncated quest item list");
            return false;
        }
    }

    LOG_DEBUG("Loot response: ", static_cast<int>(itemCount), " regular + ", static_cast<int>(questItemCount),
             " quest items, ", data.gold, " copper");
    return true;
}

// ============================================================
// NPC Gossip
// ============================================================

network::Packet GossipHelloPacket::build(uint64_t npcGuid) {
    network::Packet packet(wireOpcode(Opcode::CMSG_GOSSIP_HELLO));
    packet.writeUInt64(npcGuid);
    return packet;
}

network::Packet QuestgiverHelloPacket::build(uint64_t npcGuid) {
    network::Packet packet(wireOpcode(Opcode::CMSG_QUESTGIVER_HELLO));
    packet.writeUInt64(npcGuid);
    return packet;
}

network::Packet GossipSelectOptionPacket::build(uint64_t npcGuid, uint32_t menuId, uint32_t optionId, const std::string& code) {
    network::Packet packet(wireOpcode(Opcode::CMSG_GOSSIP_SELECT_OPTION));
    packet.writeUInt64(npcGuid);
    packet.writeUInt32(menuId);
    packet.writeUInt32(optionId);
    if (!code.empty()) {
        packet.writeString(code);
    }
    return packet;
}

network::Packet QuestgiverQueryQuestPacket::build(uint64_t npcGuid, uint32_t questId) {
    network::Packet packet(wireOpcode(Opcode::CMSG_QUESTGIVER_QUERY_QUEST));
    packet.writeUInt64(npcGuid);
    packet.writeUInt32(questId);
    packet.writeUInt8(1);  // isDialogContinued = 1 (from gossip)
    return packet;
}

network::Packet QuestgiverAcceptQuestPacket::build(uint64_t npcGuid, uint32_t questId) {
    network::Packet packet(wireOpcode(Opcode::CMSG_QUESTGIVER_ACCEPT_QUEST));
    packet.writeUInt64(npcGuid);
    packet.writeUInt32(questId);
    packet.writeUInt32(0);  // AzerothCore/WotLK expects trailing unk1
    return packet;
}

bool QuestDetailsParser::parse(network::Packet& packet, QuestDetailsData& data) {
    if (packet.getSize() < 20) return false;
    data.npcGuid = packet.readUInt64();

    // WotLK has informUnit(u64) before questId; Vanilla/TBC do not.
    // Detect: try WotLK first (read informUnit + questId), then check if title
    // string looks valid. If not, rewind and try vanilla (questId directly).
    size_t preInform = packet.getReadPos();
    /*informUnit*/ packet.readUInt64();
    data.questId = packet.readUInt32();
    data.title = normalizeWowTextTokens(packet.readString());
    if (data.title.empty() || data.questId > 100000) {
        // Likely vanilla format — rewind past informUnit
        packet.setReadPos(preInform);
        data.questId = packet.readUInt32();
        data.title = normalizeWowTextTokens(packet.readString());
    }
    data.details = normalizeWowTextTokens(packet.readString());
    data.objectives = normalizeWowTextTokens(packet.readString());

    if (!packet.hasRemaining(10)) {
        LOG_DEBUG("Quest details (short): id=", data.questId, " title='", data.title, "'");
        return true;
    }

    /*activateAccept*/ packet.readUInt8();
    /*flags*/ packet.readUInt32();
    data.suggestedPlayers = packet.readUInt32();
    /*isFinished*/ packet.readUInt8();

    // Reward choice items: server always writes 6 entries (QUEST_REWARD_CHOICES_COUNT)
    if (packet.hasRemaining(4)) {
        /*choiceCount*/ packet.readUInt32();
        for (int i = 0; i < 6; i++) {
            if (!packet.hasRemaining(12)) break;
            uint32_t itemId = packet.readUInt32();
            uint32_t count  = packet.readUInt32();
            uint32_t dispId = packet.readUInt32();
            if (itemId != 0) {
                QuestRewardItem ri;
                ri.itemId = itemId; ri.count = count; ri.displayInfoId = dispId;
                ri.choiceSlot = static_cast<uint32_t>(i);
                data.rewardChoiceItems.push_back(ri);
            }
        }
    }

    // Reward items: server always writes 4 entries (QUEST_REWARDS_COUNT)
    if (packet.hasRemaining(4)) {
        /*rewardCount*/ packet.readUInt32();
        for (int i = 0; i < 4; i++) {
            if (!packet.hasRemaining(12)) break;
            uint32_t itemId = packet.readUInt32();
            uint32_t count  = packet.readUInt32();
            uint32_t dispId = packet.readUInt32();
            if (itemId != 0) {
                QuestRewardItem ri;
                ri.itemId = itemId; ri.count = count; ri.displayInfoId = dispId;
                data.rewardItems.push_back(ri);
            }
        }
    }

    // Money and XP rewards
    if (packet.hasRemaining(4))
        data.rewardMoney = packet.readUInt32();
    if (packet.hasRemaining(4))
        data.rewardXp = packet.readUInt32();

    LOG_DEBUG("Quest details: id=", data.questId, " title='", data.title, "'");
    return true;
}

bool GossipMessageParser::parse(network::Packet& packet, GossipMessageData& data) {
    // Upfront validation: npcGuid(8) + menuId(4) + titleTextId(4) + optionCount(4) = 20 bytes minimum
    if (!packet.hasRemaining(20)) return false;

    data.npcGuid = packet.readUInt64();
    data.menuId = packet.readUInt32();
    data.titleTextId = packet.readUInt32();
    uint32_t optionCount = packet.readUInt32();

    // Cap option count to prevent unbounded memory allocation
    const uint32_t MAX_GOSSIP_OPTIONS = 64;
    if (optionCount > MAX_GOSSIP_OPTIONS) {
        LOG_WARNING("GossipMessageParser: optionCount capped (requested=", optionCount, ")");
        optionCount = MAX_GOSSIP_OPTIONS;
    }

    data.options.clear();
    data.options.reserve(optionCount);
    for (uint32_t i = 0; i < optionCount; ++i) {
        // Each option: id(4) + icon(1) + isCoded(1) + boxMoney(4) + text(var) + boxText(var)
        // Minimum: 10 bytes + 2 empty strings (2 null terminators) = 12 bytes
        if (!packet.hasRemaining(12)) {
            LOG_WARNING("GossipMessageParser: truncated options at index ", i, "/", optionCount);
            break;
        }
        GossipOption opt;
        opt.id = packet.readUInt32();
        opt.icon = packet.readUInt8();
        opt.isCoded = (packet.readUInt8() != 0);
        opt.boxMoney = packet.readUInt32();
        opt.text = packet.readString();
        opt.boxText = packet.readString();
        data.options.push_back(opt);
    }

    // Validate questCount field exists (4 bytes)
    if (!packet.hasRemaining(4)) {
        LOG_DEBUG("Gossip: ", data.options.size(), " options (no quest data)");
        return true;
    }

    uint32_t questCount = packet.readUInt32();
    // Cap quest count to prevent unbounded memory allocation
    const uint32_t MAX_GOSSIP_QUESTS = 64;
    if (questCount > MAX_GOSSIP_QUESTS) {
        LOG_WARNING("GossipMessageParser: questCount capped (requested=", questCount, ")");
        questCount = MAX_GOSSIP_QUESTS;
    }

    data.quests.clear();
    data.quests.reserve(questCount);
    for (uint32_t i = 0; i < questCount; ++i) {
        // Each quest: questId(4) + questIcon(4) + questLevel(4) + questFlags(4) + isRepeatable(1) + title(var)
        // Minimum: 17 bytes + empty string (1 null terminator) = 18 bytes
        if (!packet.hasRemaining(18)) {
            LOG_WARNING("GossipMessageParser: truncated quests at index ", i, "/", questCount);
            break;
        }
        GossipQuestItem quest;
        quest.questId = packet.readUInt32();
        quest.questIcon = packet.readUInt32();
        quest.questLevel = static_cast<int32_t>(packet.readUInt32());
        quest.questFlags = packet.readUInt32();
        quest.isRepeatable = packet.readUInt8();
        quest.title = normalizeWowTextTokens(packet.readString());
        data.quests.push_back(quest);
    }

    LOG_DEBUG("Gossip: ", data.options.size(), " options, ", data.quests.size(), " quests");
    return true;
}

// ============================================================
// Bind Point (Hearthstone)
// ============================================================

network::Packet BinderActivatePacket::build(uint64_t npcGuid) {
    network::Packet pkt(wireOpcode(Opcode::CMSG_BINDER_ACTIVATE));
    pkt.writeUInt64(npcGuid);
    return pkt;
}

bool BindPointUpdateParser::parse(network::Packet& packet, BindPointUpdateData& data) {
    if (packet.getSize() < 20) return false;
    data.x = packet.readFloat();
    data.y = packet.readFloat();
    data.z = packet.readFloat();
    data.mapId = packet.readUInt32();
    data.zoneId = packet.readUInt32();
    return true;
}

bool QuestRequestItemsParser::parse(network::Packet& packet, QuestRequestItemsData& data) {
    if (!packet.hasRemaining(20)) return false;
    data.npcGuid = packet.readUInt64();
    data.questId = packet.readUInt32();
    data.title = normalizeWowTextTokens(packet.readString());
    data.completionText = normalizeWowTextTokens(packet.readString());

    if (!packet.hasRemaining(9)) {
        LOG_DEBUG("Quest request items (short): id=", data.questId, " title='", data.title, "'");
        return true;
    }

    struct ParsedTail {
        uint32_t requiredMoney = 0;
        uint32_t completableFlags = 0;
        std::vector<QuestRewardItem> requiredItems;
        bool ok = false;
        int score = -1;
    };

    auto parseTail = [&](size_t startPos, size_t prefixSkip) -> ParsedTail {
        ParsedTail out;
        packet.setReadPos(startPos);

        if (!packet.hasRemaining(prefixSkip)) return out;
        packet.setReadPos(packet.getReadPos() + prefixSkip);

        if (!packet.hasRemaining(8)) return out;
        out.requiredMoney = packet.readUInt32();
        uint32_t requiredItemCount = packet.readUInt32();
        if (requiredItemCount > 64) return out;  // sanity guard against misalignment

        out.requiredItems.reserve(requiredItemCount);
        for (uint32_t i = 0; i < requiredItemCount; ++i) {
            if (!packet.hasRemaining(12)) return out;
            QuestRewardItem item;
            item.itemId = packet.readUInt32();
            item.count = packet.readUInt32();
            item.displayInfoId = packet.readUInt32();
            if (item.itemId != 0) out.requiredItems.push_back(item);
        }

        if (!packet.hasRemaining(4)) return out;
        out.completableFlags = packet.readUInt32();
        out.ok = true;

        // Prefer layouts that produce plausible quest-requirement shapes.
        out.score = 0;
        if (requiredItemCount <= 6) out.score += 4;
        if (out.requiredItems.size() == requiredItemCount) out.score += 3;
        if ((out.completableFlags & ~0x3u) == 0) out.score += 5;
        if (out.requiredMoney == 0) out.score += 4;
        else if (out.requiredMoney <= 100000) out.score += 2;       // <=10g is common
        else if (out.requiredMoney >= 1000000) out.score -= 3;      // implausible for most quests
        if (!out.requiredItems.empty()) out.score += 1;
        size_t remaining = packet.getRemainingSize();
        if (remaining <= 16) out.score += 3;
        else if (remaining <= 32) out.score += 2;
        else if (remaining <= 64) out.score += 1;
        if (prefixSkip == 0) out.score += 1;
        else if (prefixSkip <= 12) out.score += 1;
        return out;
    };

    size_t tailStart = packet.getReadPos();
    std::vector<ParsedTail> candidates;
    candidates.reserve(25);
    for (size_t skip = 0; skip <= 24; ++skip) {
        candidates.push_back(parseTail(tailStart, skip));
    }

    const ParsedTail* chosen = nullptr;
    for (const auto& cand : candidates) {
        if (!cand.ok) continue;
        if (!chosen || cand.score > chosen->score) chosen = &cand;
    }
    if (!chosen) {
        return true;
    }

    data.requiredMoney = chosen->requiredMoney;
    data.completableFlags = chosen->completableFlags;
    data.requiredItems = chosen->requiredItems;

    LOG_DEBUG("Quest request items: id=", data.questId, " title='", data.title,
             "' items=", data.requiredItems.size(), " completable=", data.isCompletable());
    return true;
}

bool QuestOfferRewardParser::parse(network::Packet& packet, QuestOfferRewardData& data) {
    if (!packet.hasRemaining(20)) return false;
    data.npcGuid = packet.readUInt64();
    data.questId = packet.readUInt32();
    data.title = normalizeWowTextTokens(packet.readString());
    data.rewardText = normalizeWowTextTokens(packet.readString());

    if (!packet.hasRemaining(8)) {
        LOG_DEBUG("Quest offer reward (short): id=", data.questId, " title='", data.title, "'");
        return true;
    }

    // After the two strings the packet contains a variable prefix (autoFinish + optional fields)
    // before the emoteCount.  Different expansions and server emulator versions differ:
    //   Classic 1.12   : uint8 autoFinish + uint32 suggestedPlayers  = 5 bytes
    //   TBC 2.4.3      : uint32 autoFinish + uint32 suggestedPlayers = 8 bytes (variable arrays)
    //   WotLK 3.3.5a   : uint32 autoFinish + uint32 suggestedPlayers = 8 bytes (fixed 6/4 arrays)
    // Some vanilla-family servers omit autoFinish entirely (0 bytes of prefix).
    // We scan prefix sizes 0..16 bytes with both fixed and variable array layouts, scoring each.

    struct ParsedTail {
        uint32_t rewardMoney = 0;
        uint32_t rewardXp = 0;
        std::vector<QuestRewardItem> choiceRewards;
        std::vector<QuestRewardItem> fixedRewards;
        bool ok = false;
        int score = -1000;
        size_t prefixSkip = 0;
        bool fixedArrays = false;
    };

    auto parseTail = [&](size_t startPos, size_t prefixSkip, bool fixedArrays) -> ParsedTail {
        ParsedTail out;
        out.prefixSkip  = prefixSkip;
        out.fixedArrays = fixedArrays;
        packet.setReadPos(startPos);

        // Skip the prefix bytes (autoFinish + optional suggestedPlayers before emoteCount)
        if (!packet.hasRemaining(prefixSkip)) return out;
        packet.setReadPos(packet.getReadPos() + prefixSkip);

        if (!packet.hasRemaining(4)) return out;
        uint32_t emoteCount = packet.readUInt32();
        if (emoteCount > 32) return out;  // guard against misalignment
        for (uint32_t i = 0; i < emoteCount; ++i) {
            if (!packet.hasRemaining(8)) return out;
            packet.readUInt32(); // delay
            packet.readUInt32(); // emote type
        }

        if (!packet.hasRemaining(4)) return out;
        uint32_t choiceCount = packet.readUInt32();
        if (choiceCount > 6) return out;
        uint32_t choiceSlots = fixedArrays ? 6u : choiceCount;
        out.choiceRewards.reserve(choiceCount);
        uint32_t nonZeroChoice = 0;
        for (uint32_t i = 0; i < choiceSlots; ++i) {
            if (!packet.hasRemaining(12)) return out;
            QuestRewardItem item;
            item.itemId = packet.readUInt32();
            item.count = packet.readUInt32();
            item.displayInfoId = packet.readUInt32();
            item.choiceSlot = i;
            if (item.itemId > 0) {
                out.choiceRewards.push_back(item);
                ++nonZeroChoice;
            }
        }

        if (!packet.hasRemaining(4)) return out;
        uint32_t rewardCount = packet.readUInt32();
        if (rewardCount > 4) return out;
        uint32_t rewardSlots = fixedArrays ? 4u : rewardCount;
        out.fixedRewards.reserve(rewardCount);
        uint32_t nonZeroFixed = 0;
        for (uint32_t i = 0; i < rewardSlots; ++i) {
            if (!packet.hasRemaining(12)) return out;
            QuestRewardItem item;
            item.itemId = packet.readUInt32();
            item.count = packet.readUInt32();
            item.displayInfoId = packet.readUInt32();
            if (item.itemId > 0) {
                out.fixedRewards.push_back(item);
                ++nonZeroFixed;
            }
        }

        if (packet.hasRemaining(4))
            out.rewardMoney = packet.readUInt32();
        if (packet.hasRemaining(4))
            out.rewardXp = packet.readUInt32();

        out.ok = true;
        out.score = 0;
        // Prefer the standard WotLK/TBC 8-byte prefix (uint32 autoFinish + uint32 suggestedPlayers)
        if (prefixSkip == 8) out.score += 3;
        else if (prefixSkip == 5) out.score += 1;  // Classic uint8 autoFinish + uint32 suggestedPlayers
        // Prefer fixed arrays (WotLK/TBC servers always send 6+4 slots)
        if (fixedArrays) out.score += 2;
        // Valid counts
        if (choiceCount <= 6) out.score += 3;
        if (rewardCount <= 4) out.score += 3;
        // All non-zero items are within declared counts
        if (nonZeroChoice <= choiceCount) out.score += 2;
        if (nonZeroFixed <= rewardCount) out.score += 2;
        // No bytes left over (or only a few)
        size_t remaining = packet.getRemainingSize();
        if (remaining == 0) out.score += 5;
        else if (remaining <= 4) out.score += 3;
        else if (remaining <= 8) out.score += 2;
        else if (remaining <= 16) out.score += 1;
        else out.score -= static_cast<int>(remaining / 4);
        // Plausible money/XP values
        if (out.rewardMoney < 5000000u) out.score += 1;   // < 500g
        if (out.rewardXp < 200000u) out.score += 1;       // < 200k XP
        return out;
    };

    size_t tailStart = packet.getReadPos();
    // Try prefix sizes 0..16 bytes with both fixed and variable array layouts
    std::vector<ParsedTail> candidates;
    candidates.reserve(34);
    for (size_t skip = 0; skip <= 16; ++skip) {
        candidates.push_back(parseTail(tailStart, skip, true));   // fixed arrays
        candidates.push_back(parseTail(tailStart, skip, false));  // variable arrays
    }

    const ParsedTail* best = nullptr;
    for (const auto& cand : candidates) {
        if (!cand.ok) continue;
        if (!best || cand.score > best->score) best = &cand;
    }

    if (best) {
        data.choiceRewards = best->choiceRewards;
        data.fixedRewards  = best->fixedRewards;
        data.rewardMoney   = best->rewardMoney;
        data.rewardXp      = best->rewardXp;
    }

    LOG_DEBUG("Quest offer reward: id=", data.questId, " title='", data.title,
             "' choices=", data.choiceRewards.size(), " fixed=", data.fixedRewards.size(),
             " prefix=", (best ? best->prefixSkip : size_t(0)),
             (best && best->fixedArrays ? " fixed" : " var"));
    return true;
}

network::Packet QuestgiverCompleteQuestPacket::build(uint64_t npcGuid, uint32_t questId) {
    network::Packet packet(wireOpcode(Opcode::CMSG_QUESTGIVER_COMPLETE_QUEST));
    packet.writeUInt64(npcGuid);
    packet.writeUInt32(questId);
    return packet;
}

network::Packet QuestgiverRequestRewardPacket::build(uint64_t npcGuid, uint32_t questId) {
    network::Packet packet(wireOpcode(Opcode::CMSG_QUESTGIVER_REQUEST_REWARD));
    packet.writeUInt64(npcGuid);
    packet.writeUInt32(questId);
    return packet;
}

network::Packet QuestgiverChooseRewardPacket::build(uint64_t npcGuid, uint32_t questId, uint32_t rewardIndex) {
    network::Packet packet(wireOpcode(Opcode::CMSG_QUESTGIVER_CHOOSE_REWARD));
    packet.writeUInt64(npcGuid);
    packet.writeUInt32(questId);
    packet.writeUInt32(rewardIndex);
    return packet;
}

// ============================================================
// Vendor
// ============================================================

network::Packet ListInventoryPacket::build(uint64_t npcGuid) {
    network::Packet packet(wireOpcode(Opcode::CMSG_LIST_INVENTORY));
    packet.writeUInt64(npcGuid);
    return packet;
}

network::Packet BuyItemPacket::build(uint64_t vendorGuid, uint32_t itemId, uint32_t slot, uint32_t count) {
    network::Packet packet(wireOpcode(Opcode::CMSG_BUY_ITEM));
    packet.writeUInt64(vendorGuid);
    packet.writeUInt32(itemId);  // item entry
    packet.writeUInt32(slot);    // vendor slot index from SMSG_LIST_INVENTORY
    packet.writeUInt32(count);
    // Note: WotLK/AzerothCore expects a trailing byte; Classic/TBC do not.
    // This static helper always adds it (appropriate for CMaNGOS/AzerothCore).
    // For Classic/TBC, use the GameHandler::buyItem() path which checks expansion.
    packet.writeUInt8(0);
    return packet;
}

network::Packet SellItemPacket::build(uint64_t vendorGuid, uint64_t itemGuid, uint32_t count) {
    network::Packet packet(wireOpcode(Opcode::CMSG_SELL_ITEM));
    packet.writeUInt64(vendorGuid);
    packet.writeUInt64(itemGuid);
    packet.writeUInt32(count);
    return packet;
}

network::Packet BuybackItemPacket::build(uint64_t vendorGuid, uint32_t slot) {
    network::Packet packet(wireOpcode(Opcode::CMSG_BUYBACK_ITEM));
    packet.writeUInt64(vendorGuid);
    packet.writeUInt32(slot);
    return packet;
}

bool ListInventoryParser::parse(network::Packet& packet, ListInventoryData& data) {
    // Preserve canRepair — it was set by the gossip handler before this packet
    // arrived and is not part of the wire format.
    const bool savedCanRepair = data.canRepair;
    data = ListInventoryData{};
    data.canRepair = savedCanRepair;

    if (!packet.hasRemaining(9)) {
        LOG_WARNING("ListInventoryParser: packet too short");
        return false;
    }

    data.vendorGuid = packet.readUInt64();
    uint8_t itemCount = packet.readUInt8();

    if (itemCount == 0) {
        LOG_INFO("Vendor has nothing for sale");
        return true;
    }

    // Auto-detect whether server sends 7 fields (28 bytes/item) or 8 fields (32 bytes/item).
    // Some servers omit the extendedCost field entirely; reading 8 fields on a 7-field packet
    // misaligns every item after the first and produces garbage prices.
    size_t remaining = packet.getRemainingSize();
    const size_t bytesPerItemNoExt = 28;
    const size_t bytesPerItemWithExt = 32;
    bool hasExtendedCost = false;
    if (remaining < static_cast<size_t>(itemCount) * bytesPerItemNoExt) {
        LOG_WARNING("ListInventoryParser: truncated packet (items=", static_cast<int>(itemCount),
                    ", remaining=", remaining, ")");
        return false;
    }
    if (remaining >= static_cast<size_t>(itemCount) * bytesPerItemWithExt) {
        hasExtendedCost = true;
    }

    data.items.reserve(itemCount);
    for (uint8_t i = 0; i < itemCount; ++i) {
        const size_t perItemBytes = hasExtendedCost ? bytesPerItemWithExt : bytesPerItemNoExt;
        if (!packet.hasRemaining(perItemBytes)) {
            LOG_WARNING("ListInventoryParser: item ", static_cast<int>(i), " truncated");
            return false;
        }
        VendorItem item;
        item.slot = packet.readUInt32();
        item.itemId = packet.readUInt32();
        item.displayInfoId = packet.readUInt32();
        item.maxCount = static_cast<int32_t>(packet.readUInt32());
        item.buyPrice = packet.readUInt32();
        item.durability = packet.readUInt32();
        item.stackCount = packet.readUInt32();
        item.extendedCost = hasExtendedCost ? packet.readUInt32() : 0;
        data.items.push_back(item);
    }

    LOG_DEBUG("Vendor inventory: ", static_cast<int>(itemCount), " items (extendedCost: ", hasExtendedCost ? "yes" : "no", ")");
    return true;
}

// ============================================================
// Trainer
// ============================================================

bool TrainerListParser::parse(network::Packet& packet, TrainerListData& data, bool isClassic) {
    // WotLK per-entry: spellId(4) + state(1) + cost(4) + profDialog(4) + profButton(4) +
    //                  reqLevel(1) + reqSkill(4) + reqSkillValue(4) + chain×3(12) = 38 bytes
    // Classic per-entry: spellId(4) + state(1) + cost(4) + reqLevel(1) +
    //                    reqSkill(4) + reqSkillValue(4) + chain×3(12) + unk(4) = 34 bytes
    data = TrainerListData{};
    if (!packet.hasRemaining(16)) return false; // guid(8) + type(4) + count(4)

    data.trainerGuid = packet.readUInt64();
    data.trainerType = packet.readUInt32();
    uint32_t spellCount = packet.readUInt32();

    if (spellCount > 1000) {
        LOG_ERROR("TrainerListParser: unreasonable spell count ", spellCount);
        return false;
    }

    data.spells.reserve(spellCount);
    for (uint32_t i = 0; i < spellCount; ++i) {
        // Validate minimum entry size before reading
        const size_t minEntrySize = isClassic ? 34 : 38;
        if (!packet.hasRemaining(minEntrySize)) {
            LOG_WARNING("TrainerListParser: truncated at spell ", i);
            break;
        }

        TrainerSpell spell;
        spell.spellId   = packet.readUInt32();
        spell.state     = packet.readUInt8();
        spell.spellCost = packet.readUInt32();
        if (isClassic) {
            // Classic 1.12: reqLevel immediately after cost; no profDialog/profButton
            spell.profDialog = 0;
            spell.profButton = 0;
            spell.reqLevel   = packet.readUInt8();
        } else {
            // TBC / WotLK: profDialog + profButton before reqLevel
            spell.profDialog = packet.readUInt32();
            spell.profButton = packet.readUInt32();
            spell.reqLevel   = packet.readUInt8();
        }
        spell.reqSkill      = packet.readUInt32();
        spell.reqSkillValue = packet.readUInt32();
        spell.chainNode1    = packet.readUInt32();
        spell.chainNode2    = packet.readUInt32();
        spell.chainNode3    = packet.readUInt32();
        if (isClassic) {
            packet.readUInt32(); // trailing unk / sort index
        }
        data.spells.push_back(spell);
    }

    if (!packet.hasData()) {
        LOG_WARNING("TrainerListParser: truncated before greeting");
        data.greeting.clear();
    } else {
        data.greeting = packet.readString();
    }

    LOG_INFO("Trainer list (", isClassic ? "Classic" : "TBC/WotLK", "): ",
             spellCount, " spells, type=", data.trainerType,
             ", greeting=\"", data.greeting, "\"");
    return true;
}

network::Packet TrainerBuySpellPacket::build(uint64_t trainerGuid, uint32_t spellId) {
    network::Packet packet(wireOpcode(Opcode::CMSG_TRAINER_BUY_SPELL));
    packet.writeUInt64(trainerGuid);
    packet.writeUInt32(spellId);
    return packet;
}

// ============================================================
// Talents
// ============================================================

bool TalentsInfoParser::parse(network::Packet& packet, TalentsInfoData& data) {
    // SMSG_TALENTS_INFO format (AzerothCore variant):
    // uint8  activeSpec
    // uint8  unspentPoints
    // be32   talentCount (metadata, may not match entry count)
    // be16   entryCount (actual number of id+rank entries)
    // Entry[entryCount]: { le32 id, uint8 rank }
    // le32   glyphSlots
    // le16   glyphIds[glyphSlots]

    const size_t startPos = packet.getReadPos();
    const size_t remaining = packet.getSize() - startPos;

    if (remaining < 2 + 4 + 2) {
        LOG_ERROR("SMSG_TALENTS_INFO: packet too short (remaining=", remaining, ")");
        return false;
    }

    data = TalentsInfoData{};

    // Read header
    data.talentSpec = packet.readUInt8();
    data.unspentPoints = packet.readUInt8();

    // These two counts are big-endian (network byte order)
    uint32_t talentCountBE = packet.readUInt32();
    uint32_t talentCount = bswap32(talentCountBE);

    uint16_t entryCountBE = packet.readUInt16();
    uint16_t entryCount = bswap16(entryCountBE);

    // Sanity check: prevent corrupt packets from allocating excessive memory
    if (entryCount > 64) {
        LOG_ERROR("SMSG_TALENTS_INFO: entryCount too large (", entryCount, "), rejecting packet");
        return false;
    }

    LOG_INFO("SMSG_TALENTS_INFO: spec=", static_cast<int>(data.talentSpec),
             " unspent=", static_cast<int>(data.unspentPoints),
             " talentCount=", talentCount,
             " entryCount=", entryCount);

    // Parse learned entries (id + rank pairs)
    // These may be talents, glyphs, or other learned abilities
    data.talents.clear();
    data.talents.reserve(entryCount);

    for (uint16_t i = 0; i < entryCount; ++i) {
        if (!packet.hasRemaining(5)) {
            LOG_ERROR("SMSG_TALENTS_INFO: truncated entry list at i=", i);
            return false;
        }
        uint32_t id = packet.readUInt32();  // LE
        uint8_t rank = packet.readUInt8();
        data.talents.push_back({id, rank});

        LOG_INFO("  Entry: id=", id, " rank=", static_cast<int>(rank));
    }

    // Parse glyph tail: glyphSlots + glyphIds[]
    if (!packet.hasRemaining(1)) {
        LOG_WARNING("SMSG_TALENTS_INFO: no glyph tail data");
        return true;  // Not fatal, older formats may not have glyphs
    }

    uint8_t glyphSlots = packet.readUInt8();

    // Sanity check: Wrath has 6 glyph slots, cap at 12 for safety
    if (glyphSlots > 12) {
        LOG_WARNING("SMSG_TALENTS_INFO: glyphSlots too large (", static_cast<int>(glyphSlots), "), clamping to 12");
        glyphSlots = 12;
    }

    LOG_INFO("  GlyphSlots: ", static_cast<int>(glyphSlots));

    data.glyphs.clear();
    data.glyphs.reserve(glyphSlots);

    for (uint8_t i = 0; i < glyphSlots; ++i) {
        if (!packet.hasRemaining(2)) {
            LOG_ERROR("SMSG_TALENTS_INFO: truncated glyph list at i=", i);
            return false;
        }
        uint16_t glyphId = packet.readUInt16();  // LE
        data.glyphs.push_back(glyphId);
        if (glyphId != 0) {
            LOG_INFO("    Glyph slot ", i, ": ", glyphId);
        }
    }

    LOG_INFO("SMSG_TALENTS_INFO: bytesConsumed=", (packet.getReadPos() - startPos),
             " bytesRemaining=", (packet.getRemainingSize()));

    return true;
}

network::Packet LearnTalentPacket::build(uint32_t talentId, uint32_t requestedRank) {
    network::Packet packet(wireOpcode(Opcode::CMSG_LEARN_TALENT));
    packet.writeUInt32(talentId);
    packet.writeUInt32(requestedRank);
    return packet;
}

network::Packet TalentWipeConfirmPacket::build(bool accept) {
    network::Packet packet(wireOpcode(Opcode::MSG_TALENT_WIPE_CONFIRM));
    packet.writeUInt32(accept ? 1 : 0);
    return packet;
}

network::Packet ActivateTalentGroupPacket::build(uint32_t group) {
    // CMSG_SET_ACTIVE_TALENT_GROUP_OBSOLETE (0x4C3 in WotLK 3.3.5a)
    // Payload: uint32 group (0 = primary, 1 = secondary)
    network::Packet packet(wireOpcode(Opcode::CMSG_SET_ACTIVE_TALENT_GROUP_OBSOLETE));
    packet.writeUInt32(group);
    return packet;
}

// ============================================================
// Death/Respawn
// ============================================================

network::Packet RepopRequestPacket::build() {
    network::Packet packet(wireOpcode(Opcode::CMSG_REPOP_REQUEST));
    packet.writeUInt8(1);  // request release (1 = manual)
    return packet;
}

network::Packet ReclaimCorpsePacket::build(uint64_t guid) {
    network::Packet packet(wireOpcode(Opcode::CMSG_RECLAIM_CORPSE));
    packet.writeUInt64(guid);
    return packet;
}

network::Packet SpiritHealerActivatePacket::build(uint64_t npcGuid) {
    network::Packet packet(wireOpcode(Opcode::CMSG_SPIRIT_HEALER_ACTIVATE));
    packet.writeUInt64(npcGuid);
    return packet;
}

network::Packet ResurrectResponsePacket::build(uint64_t casterGuid, bool accept) {
    network::Packet packet(wireOpcode(Opcode::CMSG_RESURRECT_RESPONSE));
    packet.writeUInt64(casterGuid);
    packet.writeUInt8(accept ? 1 : 0);
    return packet;
}

// ============================================================
// Taxi / Flight Paths
// ============================================================

} // namespace game
} // namespace wowee