#!/bin/bash

set -e

CC="${CC:-gcc}"
CFLAGS="-std=c23 -Wall -Wextra"
LIBS="-lm"
MODE="debug"
BUILDDIR=".build"
BINDIR="bin"

if command -v mold >/dev/null 2>&1; then
    LINKER_FLAGS="-fuse-ld=mold"
else
    LINKER_FLAGS=""
fi

case "$(uname)" in
    Linux)   
        LINKER_FLAGS="$LINKER_FLAGS -rdynamic"
        ;;
    Darwin)  
        ;;
    MINGW*|MSYS*|CYGWIN*)
        LINKER_FLAGS="$LINKER_FLAGS -Wl,--export-all-symbols"
        ;;
    *)
        LINKER_FLAGS="$LINKER_FLAGS -rdynamic"
        ;;
esac

RED='\033[0;31m'
GREEN='\033[0;32m'
BLUE='\033[0;34m'
BOLD='\033[1m'
NC='\033[0m'

if [[ "$(uname)" == "Linux" ]]; then
    CFLAGS="$CFLAGS -D_GNU_SOURCE"
fi

print_info() {
    echo -e "${BLUE}${BOLD}info:${NC} $1"
}

print_success() {
    echo -e "${GREEN}${BOLD}✓${NC} $1"
}

print_error() {
    echo -e "${RED}${BOLD}error:${NC} $1" >&2
}

detect_simd() {
    local simd_flags=""
    
    case "$(uname -m)" in
        x86_64|amd64)
            if $CC -mavx2 -c -x c /dev/null -o /dev/null 2>/dev/null; then
                simd_flags="-mavx2 -msse2"
            elif $CC -msse2 -c -x c /dev/null -o /dev/null 2>/dev/null; then
                simd_flags="-msse2"
            fi
            ;;
        arm64|aarch64)
            if $CC -march=armv8-a+simd -c -x c /dev/null -o /dev/null 2>/dev/null; then
                simd_flags="-march=armv8-a+simd"
            fi
            ;;
    esac
    
    echo "$simd_flags"
}

print_usage() {
    echo -e "${BOLD}pxl8${NC} - framework build tool"
    echo
    echo -e "${BOLD}USAGE:${NC}"
    echo "    ./pxl8.sh <command> [options]"
    echo
    echo -e "${BOLD}COMMANDS:${NC}"
    echo "    build        Build pxl8"
    echo "    run          Build and run pxl8 [script.fnl|script.lua]"
    echo "    clean        Remove build artifacts"
    echo "    update       Download/update all dependencies"
    echo "    vendor       Fetch source for dependencies (ex. sdl3)"
    echo "    help         Show this help message"
    echo
    echo -e "${BOLD}OPTIONS:${NC}"
    echo "    --all        Remove all artifacts including dependencies when cleaning"
    echo "    --release    Build/run in release mode"
}

COMMAND="$1"
shift || true

for arg in "$@"; do
    case $arg in
        --release)
            MODE="release"
            ;;
    esac
done

SIMD_FLAGS=$(detect_simd)

if [ "$MODE" = "release" ]; then
    CFLAGS="$CFLAGS -O3 -march=native -mtune=native -ffast-math -funroll-loops -fno-unwind-tables -fno-asynchronous-unwind-tables $SIMD_FLAGS"
    
    BUILDDIR="$BUILDDIR/release"
    BINDIR="$BINDIR/release"
else
    CFLAGS="$CFLAGS -g -O1 -DDEBUG $SIMD_FLAGS"
    BUILDDIR="$BUILDDIR/debug"
    BINDIR="$BINDIR/debug"
fi

setup_sdl3() {
    if [[ -d "lib/SDL/build" ]]; then
        SDL3_CFLAGS="-Ilib/SDL/include"
        SDL3_LIBS="-Llib/SDL/build -lSDL3"
        SDL3_RPATH="-Wl,-rpath,$(pwd)/lib/SDL/build"
        print_info "Using vendored SDL3"
    else
        SDL3_CFLAGS=$(pkg-config --cflags sdl3 2>/dev/null || echo "")
        SDL3_LIBS=$(pkg-config --libs sdl3 2>/dev/null || echo "")
        SDL3_RPATH=""
        
        if [[ -z "$SDL3_LIBS" ]]; then
            case "$(uname)" in
                Darwin)
                    SDL3_CFLAGS="-I/usr/local/include/SDL3"
                    SDL3_LIBS="-L/usr/local/lib -lSDL3"
                    ;;
                Linux)
                    SDL3_CFLAGS="-I/usr/include/SDL3"
                    SDL3_LIBS="-lSDL3"
                    ;;
                MINGW*|MSYS*|CYGWIN*)
                    SDL3_CFLAGS="-I/mingw64/include/SDL3"
                    SDL3_LIBS="-lSDL3"
                    ;;
            esac
        fi
        print_info "Using system SDL3"
    fi

    CFLAGS="$CFLAGS $SDL3_CFLAGS"
    LIBS="$LIBS $SDL3_LIBS $SDL3_RPATH"
}

update_linenoise() {
    print_info "Fetching linenoise"
    mkdir -p lib/linenoise
    
    if curl -s --max-time 5 -o lib/linenoise/linenoise.c https://raw.githubusercontent.com/antirez/linenoise/master/linenoise.c 2>/dev/null && \
       curl -s --max-time 5 -o lib/linenoise/linenoise.h https://raw.githubusercontent.com/antirez/linenoise/master/linenoise.h 2>/dev/null; then
        print_success "Updated linenoise"
    else
        print_error "Failed to download linenoise"
        return 1
    fi
}

update_fennel() {
    print_info "Fetching Fennel"
    mkdir -p lib/fennel
    
    local version="1.5.3"
    
    if curl -s --max-time 5 -o lib/fennel/fennel.lua "https://fennel-lang.org/downloads/fennel-${version}.lua" 2>/dev/null; then
        if [[ -f "lib/fennel/fennel.lua" ]] && [[ -s "lib/fennel/fennel.lua" ]]; then
            print_success "Updated Fennel (${version})"
        else
            print_error "Downloaded file is empty or missing"
            return 1
        fi
    else
        print_error "Failed to download Fennel"
        return 1
    fi
}

update_luajit() {
    print_info "Fetching LuaJIT"
    
    local version="2.1"
    local branch="v${version}"
    
    if [[ -d "lib/luajit/.git" ]]; then
        cd lib/luajit && git pull --quiet origin ${branch}
        cd - > /dev/null
    else
        rm -rf lib/luajit
        git clone --quiet --branch ${branch} https://github.com/LuaJIT/LuaJIT.git lib/luajit
    fi
    
    print_success "Updated LuaJIT (${version})"
}

build_luajit() {
    if [[ ! -f "lib/luajit/src/libluajit.a" ]]; then
        print_info "Building LuaJIT"
        cd lib/luajit
        
        if [[ "$(uname)" == "Darwin" ]]; then
            export MACOSX_DEPLOYMENT_TARGET="10.11"
        fi
        
        make clean >/dev/null 2>&1 || true
        make -j$(nproc 2>/dev/null || echo 4) > /dev/null 2>&1
        cd - > /dev/null
        print_success "Built LuaJIT"
    fi
}

update_microui() {
    print_info "Fetching microui"
    mkdir -p lib/microui/src
    
    if curl -s --max-time 5 -o lib/microui/src/microui.c https://raw.githubusercontent.com/rxi/microui/master/src/microui.c 2>/dev/null && \
       curl -s --max-time 5 -o lib/microui/src/microui.h https://raw.githubusercontent.com/rxi/microui/master/src/microui.h 2>/dev/null; then
        print_success "Updated microui"
    else
        print_error "Failed to download microui"
        return 1
    fi
}

update_miniz() {
    print_info "Fetching miniz"
    mkdir -p lib/miniz
    
    local version="3.0.2"
    
    if curl -sL --max-time 10 -o /tmp/miniz.zip "https://github.com/richgel999/miniz/releases/download/${version}/miniz-${version}.zip" 2>/dev/null; then
        unzip -qjo /tmp/miniz.zip miniz.c miniz.h -d lib/miniz/ 2>/dev/null
        rm -f /tmp/miniz.zip
        
        if [[ -f "lib/miniz/miniz.c" ]] && [[ -f "lib/miniz/miniz.h" ]]; then
            print_success "Updated miniz (${version})"
        else
            print_error "Failed to extract miniz files"
            return 1
        fi
    else
        print_error "Failed to download miniz"
        return 1
    fi
}

vendor_sdl() {
    print_info "Fetching SDL3"
    
    if [[ -d "lib/SDL/.git" ]]; then
        cd lib/SDL && git pull --quiet origin main
        cd - > /dev/null
    else
        rm -rf lib/SDL
        git clone --quiet https://github.com/libsdl-org/SDL.git lib/SDL
    fi
    
    print_success "Updated SDL3"
}

build_sdl() {
    if [[ ! -f "lib/SDL/build/libSDL3.so" ]] && [[ ! -f "lib/SDL/build/libSDL3.a" ]] && [[ ! -f "lib/SDL/build/libSDL3.dylib" ]]; then
        print_info "Building SDL3"
        mkdir -p lib/SDL/build
        cd lib/SDL/build
        cmake .. -DCMAKE_BUILD_TYPE=Release > /dev/null 2>&1
        cmake --build . --parallel $(nproc 2>/dev/null || echo 4) > /dev/null 2>&1
        cd - > /dev/null
        print_success "Built SDL3"
    fi
}

case "$COMMAND" in
    build)
        mkdir -p "$BUILDDIR"
        mkdir -p "$BINDIR"
        
        if [[ ! -f "lib/microui/src/microui.c" ]] || \
           [[ ! -d "lib/luajit" ]] || \
           [[ ! -f "lib/linenoise/linenoise.c" ]] || \
           [[ ! -f "lib/miniz/miniz.c" ]] || \
           [[ ! -f "lib/fennel/fennel.lua" ]]; then
            print_info "Missing dependencies, fetching..."
            
            update_linenoise
            update_fennel
            update_luajit
            update_microui
            update_miniz
        fi

        if [[ ! -f "bin/.gitignore" ]]; then
            echo "*" > "bin/.gitignore"
        fi

        if [[ ! -f ".build/.gitignore" ]]; then
            echo "*" > ".build/.gitignore"
        fi

        if [[ ! -f "lib/.gitignore" ]]; then
            echo "*" > "lib/.gitignore"
        fi

        if [[ -d "lib/luajit" ]]; then
            build_luajit
        fi

        if [[ -d "lib/SDL" ]]; then
            build_sdl
        fi

        setup_sdl3
        print_info "Building pxl8 ($MODE mode)"
        
        if [[ -n "$SIMD_FLAGS" ]]; then
            case "$(uname -m)" in
                x86_64|amd64)
                    if [[ "$SIMD_FLAGS" == *"mavx2"* ]]; then
                        print_info "SIMD: AVX2 + SSE2 enabled"
                    elif [[ "$SIMD_FLAGS" == *"msse2"* ]]; then
                        print_info "SIMD: SSE2 enabled"
                    fi
                    ;;
                arm64|aarch64)
                    print_info "SIMD: ARM NEON enabled"
                    ;;
            esac
        else
            print_info "SIMD: Scalar fallback"
        fi
        
        INCLUDES="-Isrc -Ilib -Ilib/microui/src -Ilib/luajit/src -Ilib/linenoise -Ilib/miniz"
        COMPILE_FLAGS="$CFLAGS $INCLUDES"
        
        EXECUTABLE="$BINDIR/pxl8"

        LIB_SOURCE_FILES="lib/linenoise/linenoise.c lib/miniz/miniz.c"

        SRC_SOURCE_FILES="
            src/pxl8.c
            src/pxl8_ase.c
            src/pxl8_blit.c
            src/pxl8_cart.c
            src/pxl8_font.c
            src/pxl8_gfx.c
            src/pxl8_io.c
            src/pxl8_lua.c
            src/pxl8_tilemap.c
            src/pxl8_tilesheet.c
            src/pxl8_vfx.c
        "

        LUAJIT_LIB="lib/luajit/src/libluajit.a"
        OBJECT_DIR="$BUILDDIR/obj"
        mkdir -p "$OBJECT_DIR"
        
        OBJECTS=""
        NEED_LINK=false
        SOURCES_COMPILED=""
        
        for src_file in $LIB_SOURCE_FILES; do
            obj_name=$(basename "$src_file" .c).o
            obj_file="$OBJECT_DIR/$obj_name"
            OBJECTS="$OBJECTS $obj_file"
            
            if [[ "$src_file" -nt "$obj_file" ]]; then
                NEED_LINK=true
                print_info "Compiling: $src_file"
                if ! $CC -c $COMPILE_FLAGS "$src_file" -o "$obj_file"; then
                    print_error "Compilation failed for $src_file"
                    exit 1
                fi
                SOURCES_COMPILED="yes"
            fi
        done
        
        for src_file in $SRC_SOURCE_FILES; do
            obj_name=$(basename "$src_file" .c).o
            obj_file="$OBJECT_DIR/$obj_name"
            OBJECTS="$OBJECTS $obj_file"
            
            if [[ "$src_file" -nt "$obj_file" ]] || \
               [[ "src/pxl8_types.h" -nt "$obj_file" ]] || \
               [[ "src/pxl8_macros.h" -nt "$obj_file" ]]; then
                NEED_LINK=true
                print_info "Compiling: $src_file"
                if ! $CC -c $COMPILE_FLAGS "$src_file" -o "$obj_file"; then
                    print_error "Compilation failed for $src_file"
                    exit 1
                fi
                SOURCES_COMPILED="yes"
            fi
        done
        
        if [[ "$LUAJIT_LIB" -nt "$EXECUTABLE" ]] || [[ "$NEED_LINK" == true ]]; then
            print_info "Linking executable"
            if ! $CC $LINKER_FLAGS $OBJECTS $LUAJIT_LIB $LIBS -o "$EXECUTABLE"; then
                print_error "Linking failed"
                exit 1
            fi
        elif [[ -z "$SOURCES_COMPILED" ]]; then
            print_info "All files are up to date, skipping build"
        fi
        
        print_success "Build complete"
        print_info "Binary: $EXECUTABLE"
        ;;

    run)
        "$0" build "$@" || exit 1
        
        SCRIPT=""
        for arg in "$@"; do
            if [[ "$arg" != "--release" ]]; then
                SCRIPT="$arg"
                break
            fi
        done
        
        if [[ -z "$SCRIPT" ]]; then
            SCRIPT="src/fnl/demo.fnl"
        fi
        
        "$BINDIR/pxl8" "$SCRIPT"
        ;;

    clean)
        if [[ "$1" == "--all" ]] || [[ "$1" == "--deps" ]]; then
            print_info "Removing all build artifacts and dependencies"
            rm -rf "$BUILDDIR" "$BINDIR" lib
        else
            print_info "Removing build artifacts"
            rm -rf "$BUILDDIR" "$BINDIR"
        fi
        print_success "Cleaned"
        ;;

    update)
        update_linenoise
        update_fennel
        update_luajit
        update_microui
        update_miniz
        print_success "All dependencies updated"
        ;;

    vendor)
        vendor_sdl
        ;;

    help|--help|-h|"")
        print_usage
        ;;

    *)
        print_error "Unknown command: $COMMAND"
        print_usage
        exit 1
        ;;
esac