#pragma once

#include "pipeline/m2_loader.hpp"
#include <vulkan/vulkan.h>
#include <vk_mem_alloc.h>
#include <glm/glm.hpp>
#include <memory>
#include <vector>
#include <unordered_map>
#include <unordered_set>
#include <string>
#include <utility>
#include <future>

namespace wowee {
namespace pipeline { class AssetManager; }
namespace rendering {

// Forward declarations
class Camera;
class VkContext;
class VkTexture;

// Weapon attached to a character instance at a bone attachment point
struct WeaponAttachment {
    uint32_t weaponModelId;
    uint32_t weaponInstanceId;
    uint32_t attachmentId;     // 1=RightHand, 2=LeftHand
    uint16_t boneIndex;
    glm::vec3 offset;
};

/**
 * Character renderer for M2 models with skeletal animation
 *
 * Features:
 * - Skeletal animation with bone transformations
 * - Keyframe interpolation (linear position/scale, slerp rotation)
 * - Vertex skinning (GPU-accelerated via bone SSBO)
 * - Texture loading from BLP via AssetManager
 */
class CharacterRenderer {
public:
    CharacterRenderer();
    ~CharacterRenderer();

    bool initialize(VkContext* ctx, VkDescriptorSetLayout perFrameLayout, pipeline::AssetManager* am,
                    VkRenderPass renderPassOverride = VK_NULL_HANDLE,
                    VkSampleCountFlagBits msaaSamples = VK_SAMPLE_COUNT_1_BIT);
    void shutdown();

    void setAssetManager(pipeline::AssetManager* am) { assetManager = am; }

    bool loadModel(const pipeline::M2Model& model, uint32_t id);

    uint32_t createInstance(uint32_t modelId, const glm::vec3& position,
                           const glm::vec3& rotation = glm::vec3(0.0f),
                           float scale = 1.0f);

    void playAnimation(uint32_t instanceId, uint32_t animationId, bool loop = true);

    void update(float deltaTime, const glm::vec3& cameraPos = glm::vec3(0.0f));

    void render(VkCommandBuffer cmd, VkDescriptorSet perFrameSet, const Camera& camera);
    void recreatePipelines();
    bool initializeShadow(VkRenderPass shadowRenderPass);
    void renderShadow(VkCommandBuffer cmd, const glm::mat4& lightSpaceMatrix,
                      const glm::vec3& shadowCenter = glm::vec3(0), float shadowRadius = 1e9f);

    void setInstancePosition(uint32_t instanceId, const glm::vec3& position);
    void setInstanceRotation(uint32_t instanceId, const glm::vec3& rotation);
    void moveInstanceTo(uint32_t instanceId, const glm::vec3& destination, float durationSeconds);
    void startFadeIn(uint32_t instanceId, float durationSeconds);
    const pipeline::M2Model* getModelData(uint32_t modelId) const;
    void setActiveGeosets(uint32_t instanceId, const std::unordered_set<uint16_t>& geosets);
    void setGroupTextureOverride(uint32_t instanceId, uint16_t geosetGroup, VkTexture* texture);
    void setTextureSlotOverride(uint32_t instanceId, uint16_t textureSlot, VkTexture* texture);
    void clearTextureSlotOverride(uint32_t instanceId, uint16_t textureSlot);
    void setInstanceVisible(uint32_t instanceId, bool visible);
    void removeInstance(uint32_t instanceId);
    bool getAnimationState(uint32_t instanceId, uint32_t& animationId, float& animationTimeMs, float& animationDurationMs) const;
    bool hasAnimation(uint32_t instanceId, uint32_t animationId) const;
    bool getAnimationSequences(uint32_t instanceId, std::vector<pipeline::M2Sequence>& out) const;
    bool getInstanceModelName(uint32_t instanceId, std::string& modelName) const;
    bool getInstanceBounds(uint32_t instanceId, glm::vec3& outCenter, float& outRadius) const;
    bool getInstanceFootZ(uint32_t instanceId, float& outFootZ) const;

    /** Debug: Log all available animations for an instance */
    void dumpAnimations(uint32_t instanceId) const;

    /** Attach a weapon model to a character instance at the given attachment point. */
    bool attachWeapon(uint32_t charInstanceId, uint32_t attachmentId,
                      const pipeline::M2Model& weaponModel, uint32_t weaponModelId,
                      const std::string& texturePath);

    /** Detach a weapon from the given attachment point. */
    void detachWeapon(uint32_t charInstanceId, uint32_t attachmentId);

    /** Get the world-space transform of an attachment point on an instance. */
    bool getAttachmentTransform(uint32_t instanceId, uint32_t attachmentId, glm::mat4& outTransform);

    size_t getInstanceCount() const { return instances.size(); }

    // Normal mapping / POM settings
    void setNormalMappingEnabled(bool enabled) { normalMappingEnabled_ = enabled; }
    void setNormalMapStrength(float strength) { normalMapStrength_ = strength; }
    void setPOMEnabled(bool enabled) { pomEnabled_ = enabled; }
    void setPOMQuality(int quality) { pomQuality_ = quality; }

    // Fog/lighting/shadow are now in per-frame UBO — keep stubs for callers that haven't been updated
    void setFog(const glm::vec3&, float, float) {}
    void setLighting(const float[3], const float[3], const float[3]) {}
    void setShadowMap(VkTexture*, const glm::mat4&) {}
    void clearShadowMap() {}

private:
    // GPU representation of M2 model
    struct M2ModelGPU {
        VkBuffer vertexBuffer = VK_NULL_HANDLE;
        VmaAllocation vertexAlloc = VK_NULL_HANDLE;
        VkBuffer indexBuffer = VK_NULL_HANDLE;
        VmaAllocation indexAlloc = VK_NULL_HANDLE;
        uint32_t indexCount = 0;
        uint32_t vertexCount = 0;

        pipeline::M2Model data;  // Original model data
        std::vector<glm::mat4> bindPose;  // Inverse bind pose matrices

        // Textures loaded from BLP (indexed by texture array position)
        std::vector<VkTexture*> textureIds;
    };

    // Character instance
    struct CharacterInstance {
        uint32_t id;
        uint32_t modelId;

        glm::vec3 position;
        glm::vec3 rotation;
        float scale;
        bool visible = true;  // For first-person camera hiding

        // Animation state
        uint32_t currentAnimationId = 0;
        int currentSequenceIndex = -1;  // Index into M2Model::sequences
        float animationTime = 0.0f;
        bool animationLoop = true;
        bool isDead = false;  // Prevents movement while in death state
        std::vector<glm::mat4> boneMatrices;  // Current bone transforms

        // Geoset visibility — which submesh IDs to render
        // Empty = render all (for non-character models)
        std::unordered_set<uint16_t> activeGeosets;

        // Per-geoset-group texture overrides (group → VkTexture*)
        std::unordered_map<uint16_t, VkTexture*> groupTextureOverrides;

        // Per-texture-slot overrides (slot → VkTexture*)
        std::unordered_map<uint16_t, VkTexture*> textureSlotOverrides;

        // Weapon attachments (weapons parented to this instance's bones)
        std::vector<WeaponAttachment> weaponAttachments;

        // Opacity (for fade-in)
        float opacity = 1.0f;
        float fadeInTime = 0.0f;     // elapsed fade time (seconds)
        float fadeInDuration = 0.0f; // total fade duration (0 = no fade)

        // Movement interpolation
        bool isMoving = false;
        glm::vec3 moveStart{0.0f};
        glm::vec3 moveEnd{0.0f};
        float moveDuration = 0.0f;   // seconds
        float moveElapsed = 0.0f;

        // Override model matrix (used for weapon instances positioned by parent bone)
        bool hasOverrideModelMatrix = false;
        glm::mat4 overrideModelMatrix{1.0f};

        // Per-instance bone SSBO (double-buffered per frame)
        VkBuffer boneBuffer[2] = {};
        VmaAllocation boneAlloc[2] = {};
        void* boneMapped[2] = {};
        VkDescriptorSet boneSet[2] = {};
    };

    void setupModelBuffers(M2ModelGPU& gpuModel);
    void calculateBindPose(M2ModelGPU& gpuModel);
    void updateAnimation(CharacterInstance& instance, float deltaTime);
    void calculateBoneMatrices(CharacterInstance& instance);
    glm::mat4 getBoneTransform(const pipeline::M2Bone& bone, float time, int sequenceIndex);
    glm::mat4 getModelMatrix(const CharacterInstance& instance) const;
    void destroyModelGPU(M2ModelGPU& gpuModel);
    void destroyInstanceBones(CharacterInstance& inst);

    // Keyframe interpolation helpers
    static int findKeyframeIndex(const std::vector<uint32_t>& timestamps, float time);
    static glm::vec3 interpolateVec3(const pipeline::M2AnimationTrack& track,
                                      int seqIdx, float time, const glm::vec3& defaultVal);
    static glm::quat interpolateQuat(const pipeline::M2AnimationTrack& track,
                                      int seqIdx, float time);

public:
    /**
     * Build a composited character skin texture by alpha-blending overlay
     * layers onto a base skin BLP. Returns the resulting VkTexture*.
     */
    VkTexture* compositeTextures(const std::vector<std::string>& layerPaths);

    /**
     * Build a composited character skin with explicit region-based equipment overlays.
     */
    VkTexture* compositeWithRegions(const std::string& basePath,
                                const std::vector<std::string>& baseLayers,
                                const std::vector<std::pair<int, std::string>>& regionLayers);

    /** Clear the composite texture cache (forces re-compositing on next call). */
    void clearCompositeCache();

    /** Load a BLP texture from MPQ and return VkTexture* (cached). */
    VkTexture* loadTexture(const std::string& path);
    VkTexture* getTransparentTexture() const { return transparentTexture_.get(); }

    /** Replace a loaded model's texture at the given slot. */
    void setModelTexture(uint32_t modelId, uint32_t textureSlot, VkTexture* texture);

    /** Reset a model's texture slot back to white fallback. */
    void resetModelTexture(uint32_t modelId, uint32_t textureSlot);


private:
    VkContext* vkCtx_ = nullptr;
    VkRenderPass renderPassOverride_ = VK_NULL_HANDLE;
    VkSampleCountFlagBits msaaSamplesOverride_ = VK_SAMPLE_COUNT_1_BIT;
    pipeline::AssetManager* assetManager = nullptr;

    // Vulkan pipelines (one per blend mode)
    VkPipeline opaquePipeline_ = VK_NULL_HANDLE;
    VkPipeline alphaTestPipeline_ = VK_NULL_HANDLE;
    VkPipeline alphaPipeline_ = VK_NULL_HANDLE;
    VkPipeline additivePipeline_ = VK_NULL_HANDLE;
    VkPipelineLayout pipelineLayout_ = VK_NULL_HANDLE;

    // Descriptor set layouts
    VkDescriptorSetLayout perFrameLayout_ = VK_NULL_HANDLE;  // set 0 (owned by Renderer)
    VkDescriptorSetLayout materialSetLayout_ = VK_NULL_HANDLE;  // set 1
    VkDescriptorSetLayout boneSetLayout_ = VK_NULL_HANDLE;  // set 2

    // Descriptor pool
    VkDescriptorPool materialDescPools_[2] = {VK_NULL_HANDLE, VK_NULL_HANDLE};
    VkDescriptorPool boneDescPool_ = VK_NULL_HANDLE;
    uint32_t lastMaterialPoolResetFrame_ = 0xFFFFFFFFu;
    std::vector<std::pair<VkBuffer, VmaAllocation>> transientMaterialUbos_[2];

    // Texture cache
    struct TextureCacheEntry {
        std::unique_ptr<VkTexture> texture;
        std::unique_ptr<VkTexture> normalHeightMap;
        float heightMapVariance = 0.0f;
        size_t approxBytes = 0;
        uint64_t lastUse = 0;
        bool hasAlpha = false;
        bool colorKeyBlack = false;
    };
    std::unordered_map<std::string, TextureCacheEntry> textureCache;
    std::unordered_map<VkTexture*, bool> textureHasAlphaByPtr_;
    std::unordered_map<VkTexture*, bool> textureColorKeyBlackByPtr_;
    std::unordered_map<std::string, VkTexture*> compositeCache_;  // key → texture for reuse
    std::unordered_set<std::string> failedTextureCache_;  // negative cache for budget exhaustion
    std::unordered_set<std::string> loggedTextureLoadFails_;  // dedup warning logs
    size_t textureCacheBytes_ = 0;
    uint64_t textureCacheCounter_ = 0;
    size_t textureCacheBudgetBytes_ = 1024ull * 1024 * 1024;
    uint32_t textureBudgetRejectWarnings_ = 0;
    std::unique_ptr<VkTexture> whiteTexture_;
    std::unique_ptr<VkTexture> transparentTexture_;
    std::unique_ptr<VkTexture> flatNormalTexture_;

    std::unordered_map<uint32_t, M2ModelGPU> models;
    std::unordered_map<uint32_t, CharacterInstance> instances;

    uint32_t nextInstanceId = 1;

    // Normal map generation (same algorithm as WMO renderer)
    std::unique_ptr<VkTexture> generateNormalHeightMap(
        const uint8_t* pixels, uint32_t width, uint32_t height, float& outVariance);

    // Normal mapping / POM settings
    bool normalMappingEnabled_ = true;
    float normalMapStrength_ = 0.8f;
    bool pomEnabled_ = true;
    int pomQuality_ = 1;  // 0=Low(16), 1=Medium(32), 2=High(64)

    // Maximum bones supported
    static constexpr int MAX_BONES = 240;
    uint32_t numAnimThreads_ = 1;
    std::vector<std::future<void>> animFutures_;

    // Shadow pipeline resources
    VkPipeline shadowPipeline_ = VK_NULL_HANDLE;
    VkPipelineLayout shadowPipelineLayout_ = VK_NULL_HANDLE;
    VkDescriptorSetLayout shadowParamsLayout_ = VK_NULL_HANDLE;
    VkDescriptorPool shadowParamsPool_ = VK_NULL_HANDLE;
    VkDescriptorSet shadowParamsSet_ = VK_NULL_HANDLE;
    VkBuffer shadowParamsUBO_ = VK_NULL_HANDLE;
    VmaAllocation shadowParamsAlloc_ = VK_NULL_HANDLE;
};

} // namespace rendering
} // namespace wowee