#!/usr/bin/env bash
# test.sh — Run the C++ linter (clang-tidy) against all first-party sources.
#
# Usage:
#   ./test.sh            # lint src/ and include/ using build/compile_commands.json
#   FIX=1 ./test.sh      # apply suggested fixes automatically (use with care)
#
# Exit code is non-zero if any clang-tidy diagnostic is emitted.

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
cd "$SCRIPT_DIR"

# ---------------------------------------------------------------------------
# Dependency check
# ---------------------------------------------------------------------------
CLANG_TIDY=""
for candidate in clang-tidy clang-tidy-18 clang-tidy-17 clang-tidy-16 clang-tidy-15 clang-tidy-14; do
    if command -v "$candidate" >/dev/null 2>&1; then
        CLANG_TIDY="$candidate"
        break
    fi
done

if [[ -z "$CLANG_TIDY" ]]; then
    echo "clang-tidy not found. Install it with:"
    echo "  sudo apt-get install clang-tidy"
    exit 1
fi

echo "Using: $($CLANG_TIDY --version | head -1)"

# run-clang-tidy runs checks in parallel; fall back to sequential if absent.
RUN_CLANG_TIDY=""
for candidate in run-clang-tidy run-clang-tidy-18 run-clang-tidy-17 run-clang-tidy-16 run-clang-tidy-15 run-clang-tidy-14; do
    if command -v "$candidate" >/dev/null 2>&1; then
        RUN_CLANG_TIDY="$candidate"
        break
    fi
done

# ---------------------------------------------------------------------------
# Build database check
# ---------------------------------------------------------------------------
COMPILE_COMMANDS="$SCRIPT_DIR/build/compile_commands.json"
if [[ ! -f "$COMPILE_COMMANDS" ]]; then
    echo "compile_commands.json not found at $COMPILE_COMMANDS"
    echo "Run cmake first:  cmake -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON"
    exit 1
fi

# ---------------------------------------------------------------------------
# Source files to check (first-party only)
# ---------------------------------------------------------------------------
mapfile -t SOURCE_FILES < <(
    find "$SCRIPT_DIR/src" -type f \( -name '*.cpp' -o -name '*.cxx' -o -name '*.cc' \) | sort
)

if [[ ${#SOURCE_FILES[@]} -eq 0 ]]; then
    echo "No source files found in src/"
    exit 0
fi

echo "Linting ${#SOURCE_FILES[@]} source files..."

# ---------------------------------------------------------------------------
# Resolve GCC C++ stdlib include paths for clang-tidy
#
# compile_commands.json is generated by GCC. When clang-tidy processes those
# commands with its own clang driver it cannot locate GCC's libstdc++ headers.
# We query GCC for its include search list and forward each path as an
# -isystem extra argument so clang-tidy can find <vector>, <string>, etc.
# ---------------------------------------------------------------------------
EXTRA_TIDY_ARGS=()   # for direct clang-tidy:  --extra-arg=...
EXTRA_RUN_ARGS=()    # for run-clang-tidy:     -extra-arg=...
if command -v gcc >/dev/null 2>&1; then
    while IFS= read -r inc_path; do
        [[ -d "$inc_path" ]] || continue
        EXTRA_TIDY_ARGS+=("--extra-arg=-isystem${inc_path}")
        EXTRA_RUN_ARGS+=("-extra-arg=-isystem${inc_path}")
    done < <(
        gcc -E -x c++ - -v < /dev/null 2>&1 \
        | sed -n '/#include <\.\.\.> search starts here:/,/End of search list\./p' \
        | grep '^ ' \
        | sed 's/^ //'
    )
fi

# ---------------------------------------------------------------------------
# Run
# ---------------------------------------------------------------------------
FIX="${FIX:-0}"
FIX_FLAG=""
if [[ "$FIX" == "1" ]]; then
    FIX_FLAG="-fix"
    echo "Fix mode enabled — applying suggested fixes."
fi

FAILED=0

if [[ -n "$RUN_CLANG_TIDY" ]]; then
    echo "Running via $RUN_CLANG_TIDY (parallel)..."
    # run-clang-tidy takes a source-file regex; match our src/ tree
    SRC_REGEX="$(echo "$SCRIPT_DIR/src" | sed 's|/|\\/|g')"
    "$RUN_CLANG_TIDY" \
        -clang-tidy-binary "$CLANG_TIDY" \
        -p "$SCRIPT_DIR/build" \
        $FIX_FLAG \
        "${EXTRA_RUN_ARGS[@]}" \
        "$SRC_REGEX" || FAILED=$?
else
    echo "run-clang-tidy not found; running sequentially..."
    for f in "${SOURCE_FILES[@]}"; do
        "$CLANG_TIDY" \
            -p "$SCRIPT_DIR/build" \
            $FIX_FLAG \
            "${EXTRA_TIDY_ARGS[@]}" \
            "$f" || FAILED=$?
    done
fi

# ---------------------------------------------------------------------------
# Result
# ---------------------------------------------------------------------------
if [[ $FAILED -ne 0 ]]; then
    echo ""
    echo "clang-tidy reported issues. Fix them or add suppressions in .clang-tidy."
    exit 1
fi

echo ""
echo "Lint passed."