#!/usr/bin/env bash
# ─────────────────────────────────────────────────────────────────────────────
# build-windows.sh
#
# Cross-compiles photo-converter for Windows (x86_64) using MinGW-w64.
# Produces a self-contained directory with photo-converter.exe and all
# required DLLs ready for distribution.
#
# Prerequisites (Ubuntu/Debian):
#   sudo apt install mingw-w64 cmake ninja-build
#   # Install MinGW-w64 cross builds of OpenCV, LibRaw, Qt6:
#   #   Option A – compile from source with the MinGW toolchain.
#   #   Option B – use an MXE (M cross environment) prefix.
#   #              https://mxe.cc/
#   #   Option C – use pre-built MinGW packages from a provider such as
#   #              https://github.com/brechtsanders/winlibs_mingw
#
# Usage:
#   bash scripts/build-windows.sh [BUILD_TYPE] [DEPS_PREFIX]
#
#   BUILD_TYPE    Release (default) | Debug | RelWithDebInfo
#   DEPS_PREFIX   Path to cross-compiled dependencies
#                 (default: /usr/x86_64-w64-mingw32)
#
# Example with a custom MXE prefix:
#   bash scripts/build-windows.sh Release /opt/mxe/usr/x86_64-w64-mingw32.static
# ─────────────────────────────────────────────────────────────────────────────

set -euo pipefail

# ── Configuration ─────────────────────────────────────────────────────────────
BUILD_TYPE="${1:-Release}"
DEPS_PREFIX="${2:-/usr/x86_64-w64-mingw32}"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
BUILD_DIR="${PROJECT_ROOT}/build-windows"
DIST_DIR="${PROJECT_ROOT}/dist-windows"

TOOLCHAIN="${PROJECT_ROOT}/cmake/toolchain-mingw64.cmake"

echo "========================================================"
echo "  photo-converter  Windows Cross-Compilation"
echo "========================================================"
echo "  Project root : ${PROJECT_ROOT}"
echo "  Build dir    : ${BUILD_DIR}"
echo "  Build type   : ${BUILD_TYPE}"
echo "  Deps prefix  : ${DEPS_PREFIX}"
echo "========================================================"

# ── Verify prerequisites ──────────────────────────────────────────────────────
for tool in x86_64-w64-mingw32-g++ cmake ninja; do
    if ! command -v "${tool}" &>/dev/null; then
        echo "ERROR: '${tool}' not found in PATH." >&2
        echo "Install with: sudo apt install mingw-w64 cmake ninja-build" >&2
        exit 1
    fi
done

# ── CMake configure ──────────────────────────────────────────────────────────
cmake \
    -B "${BUILD_DIR}" \
    -G Ninja \
    -DCMAKE_TOOLCHAIN_FILE="${TOOLCHAIN}" \
    -DCMAKE_BUILD_TYPE="${BUILD_TYPE}" \
    -DCMAKE_INSTALL_PREFIX="${DIST_DIR}" \
    -DCMAKE_PREFIX_PATH="${DEPS_PREFIX}" \
    -DBUILD_TESTS=OFF \
    -DBUILD_GUI=ON \
    "${PROJECT_ROOT}"

# ── Build ─────────────────────────────────────────────────────────────────────
cmake --build "${BUILD_DIR}" -- -j"$(nproc)"

# ── Install to dist dir ───────────────────────────────────────────────────────
cmake --install "${BUILD_DIR}"

# ── Collect runtime DLLs ─────────────────────────────────────────────────────
# MinGW runtime and dependency DLLs must ship alongside the .exe.
BIN_DIR="${DIST_DIR}/bin"
mkdir -p "${BIN_DIR}"

echo ""
echo "Collecting runtime DLLs..."

# Helper: copy a DLL if it exists in the sysroot.
copy_dll() {
    local dll_name="$1"
    local search_paths=(
        "${DEPS_PREFIX}/bin"
        "${DEPS_PREFIX}/lib"
        "/usr/lib/gcc/x86_64-w64-mingw32"
        "/usr/x86_64-w64-mingw32/lib"
    )
    for dir in "${search_paths[@]}"; do
        if [[ -f "${dir}/${dll_name}" ]]; then
            cp -v "${dir}/${dll_name}" "${BIN_DIR}/"
            return 0
        fi
    done
    echo "  WARNING: ${dll_name} not found (may be statically linked)" >&2
    return 0
}

# MinGW runtime DLLs (may be statically linked via -static-libgcc/-static-libstdc++)
copy_dll "libgcc_s_seh-1.dll"     || true
copy_dll "libstdc++-6.dll"        || true
copy_dll "libwinpthread-1.dll"    || true

# OpenCV DLLs (names include version number – use glob)
for dll in "${DEPS_PREFIX}/bin"/libopencv_*.dll; do
    [[ -f "${dll}" ]] && cp -v "${dll}" "${BIN_DIR}/"
done

# LibRaw
copy_dll "libraw.dll"   || true
copy_dll "libraw-23.dll" || true

# Qt6 DLLs
for qt_dll in Qt6Core Qt6Gui Qt6Widgets; do
    copy_dll "${qt_dll}.dll" || true
done

# Qt platform plugin
QT_PLATFORMS_SRC="${DEPS_PREFIX}/share/qt6/plugins/platforms"
if [[ -d "${QT_PLATFORMS_SRC}" ]]; then
    mkdir -p "${BIN_DIR}/platforms"
    cp -v "${QT_PLATFORMS_SRC}/qwindows.dll" "${BIN_DIR}/platforms/" 2>/dev/null || true
fi

# ── Strip release binaries ────────────────────────────────────────────────────
if [[ "${BUILD_TYPE}" == "Release" ]]; then
    echo ""
    echo "Stripping debug symbols from release binaries..."
    x86_64-w64-mingw32-strip --strip-all "${BIN_DIR}/photo-converter.exe" 2>/dev/null || true
    find "${BIN_DIR}" -name "*.dll" -exec x86_64-w64-mingw32-strip --strip-unneeded {} \; 2>/dev/null || true
fi

# ── Copy example config ───────────────────────────────────────────────────────
cp -v "${PROJECT_ROOT}/config.ini" "${DIST_DIR}/config.ini.example"

# ── Create ZIP archive ────────────────────────────────────────────────────────
ARCHIVE="${PROJECT_ROOT}/photo-converter-windows-x64-${BUILD_TYPE}.zip"
if command -v zip &>/dev/null; then
    (cd "${PROJECT_ROOT}" && zip -r "${ARCHIVE}" "dist-windows/")
    echo ""
    echo "Archive: ${ARCHIVE}"
else
    echo "(zip not available; skipping archive creation)"
fi

echo ""
echo "========================================================"
echo "  Build complete!"
echo "  Output: ${DIST_DIR}"
echo "  Run: wine ${BIN_DIR}/photo-converter.exe --help"
echo "========================================================"