#!/bin/bash
#
# OpenWrt-Yocto macOS Build Environment Setup
#
# Usage: ./setup-env-macos.sh [command]
#
# Commands:
#   setup    - Build the Docker image (default)
#   shell    - Enter the interactive build container
#   build    - Run bitbake inside the container (requires target, e.g. ./setup-env-macos.sh build openwrt-image-base)
#   clean    - Remove the Docker image and container
#   help     - Show this help message
#
# ─── Important Notes ───────────────────────────────────────────────────────
#
# 1. Yocto Project does NOT natively support macOS. This script uses
#    Docker to run an Ubuntu container with all required build dependencies.
#
# 2. macOS uses a case-INSENSITIVE filesystem by default. Yocto REQUIRES
#    a case-sensitive filesystem. This script will detect this and warn you.
#
# 3. You need at least 50GB of free disk space for a full build.
#
# 4. First-time setup will build a Docker image (~1GB) which may take a few minutes.
#
# ─── Prerequisites ──────────────────────────────────────────────────────────
#
# Install Docker Desktop for Mac: https://docs.docker.com/desktop/setup/mac/
#
#   brew install --cask docker   (if using Homebrew)
#
# After installation, open Docker Desktop and ensure it's running.
#

set -e

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
IMAGE_NAME="openwrt-yocto-builder"
IMAGE_TAG="latest"
CONTAINER_NAME="openwrt-yocto-build"

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
CYAN='\033[0;36m'
NC='\033[0m' # No Color

print_header() {
    echo ""
    echo -e "${CYAN}╔══════════════════════════════════════════════════════════════╗${NC}"
    echo -e "${CYAN}║     OpenWrt-Yocto macOS Build Environment Setup             ║${NC}"
    echo -e "${CYAN}╚══════════════════════════════════════════════════════════════╝${NC}"
    echo ""
}

print_error()   { echo -e "${RED}[ERROR]${NC} $1"; }
print_warning() { echo -e "${YELLOW}[WARN]${NC} $1"; }
print_info()    { echo -e "${GREEN}[INFO]${NC} $1"; }
print_step()    { echo -e "${CYAN}[STEP]${NC} $1"; }

# ─── Prerequisite Checks ────────────────────────────────────────────────────

check_prerequisites() {
    print_step "Checking prerequisites..."

    # Check Docker
    if ! command -v docker &>/dev/null; then
        print_error "Docker is not installed."
        echo ""
        echo "  Please install Docker Desktop for Mac:"
        echo "    https://docs.docker.com/desktop/setup/mac/"
        echo ""
        echo "  Or via Homebrew:"
        echo "    brew install --cask docker"
        echo ""
        exit 1
    fi

    # Check if Docker daemon is running
    if ! docker info &>/dev/null; then
        print_error "Docker daemon is not running."
        echo "  Please start Docker Desktop and try again."
        exit 1
    fi

    print_info "Docker is installed and running."

    # Check disk space (at least 50GB recommended)
    local available_gb
    available_gb=$(df -g . | awk 'NR==2 {print $4}')
    if [ "$available_gb" -lt 50 ]; then
        print_warning "Less than 50GB free disk space detected (${available_gb}GB available)."
        echo "  Yocto builds require significant disk space. You may run out of space."
        echo "  Continue anyway? (y/N)"
        read -r response
        if [[ ! "$response" =~ ^[Yy]$ ]]; then
            exit 1
        fi
    else
        print_info "Disk space OK: ${available_gb}GB available."
    fi

    # Check for case-sensitive filesystem warning
    # macOS default APFS is case-insensitive, which breaks Yocto builds
    local fs_type
    fs_type=$(df -T . | awk 'NR==2 {print $2}')
    if [[ "$(uname)" == "Darwin" ]]; then
        print_warning "macOS uses a case-insensitive filesystem by default."
        echo ""
        echo "  Yocto Project REQUIRES a case-sensitive filesystem."
        echo "  The build will happen inside a Docker container (Linux), so this"
        echo "  is only an issue if you extract source tarballs on macOS directly."
        echo "  Docker volumes handle case sensitivity correctly."
        echo ""
        echo "  If you encounter 'file not found' errors, ensure all source files"
        echo "  are downloaded/cached inside the Docker container."
        echo ""
    fi
}

# ─── Docker Image Management ─────────────────────────────────────────────────

build_image() {
    print_step "Building Docker image '${IMAGE_NAME}:${IMAGE_TAG}'..."

    # Pass host user's UID/GID so container user matches
    docker build \
        --build-arg USER_UID="$(id -u)" \
        --build-arg USER_GID="$(id -g)" \
        -t "${IMAGE_NAME}:${IMAGE_TAG}" \
        -f "$SCRIPT_DIR/Dockerfile" \
        "$SCRIPT_DIR"

    print_info "Docker image built successfully."
}

image_exists() {
    docker image inspect "${IMAGE_NAME}:${IMAGE_TAG}" &>/dev/null
}

# ─── Container Management ────────────────────────────────────────────────────

enter_shell() {
    print_step "Entering build container..."

    # Ensure image exists
    if ! image_exists; then
        print_info "Docker image not found. Building it first..."
        build_image
    fi

    # Check if container already exists and is running
    if docker ps --format '{{.Names}}' | grep -q "^${CONTAINER_NAME}$"; then
        print_info "Attaching to running container '${CONTAINER_NAME}'..."
        docker exec -it "${CONTAINER_NAME}" /bin/bash
        return
    fi

    # Check if container exists but stopped
    if docker ps -a --format '{{.Names}}' | grep -q "^${CONTAINER_NAME}$"; then
        print_info "Starting existing container '${CONTAINER_NAME}'..."
        docker start "${CONTAINER_NAME}"
        docker exec -it "${CONTAINER_NAME}" /bin/bash
        return
    fi

    # Run a new container
    print_info "Creating new container '${CONTAINER_NAME}'..."
    docker run -it --rm \
        --name "${CONTAINER_NAME}" \
        -v "$SCRIPT_DIR:/workspace" \
        -v "${HOME}/.gitconfig:/home/builduser/.gitconfig:ro" \
        "${IMAGE_NAME}:${IMAGE_TAG}" \
        -c "
            echo ''
            echo '╔═══════════════════════════════════════════════════════╗'
            echo '║   OpenWrt-Yocto Docker Build Environment             ║'
            echo '║   OS: Ubuntu 24.04                                   ║'
            echo '║   Project: /workspace                                ║'
            echo '╚═══════════════════════════════════════════════════════╝'
            echo ''
            echo 'Quick start:'
            echo '  source ./setup-env.sh            # Initialize build environment'
            echo '  bitbake openwrt-image-base       # Build the base image'
            echo ''
            exec /bin/bash
        "
}

run_bitbake() {
    local target="$1"
    if [ -z "$target" ]; then
        print_error "BitBake target is required."
        echo "  Usage: ./setup-env-macos.sh build <target>"
        echo "  Example: ./setup-env-macos.sh build openwrt-image-base"
        exit 1
    fi

    print_step "Building target: ${target}"

    # Ensure image exists
    if ! image_exists; then
        print_info "Docker image not found. Building it first..."
        build_image
    fi

    docker run -it --rm \
        --name "${CONTAINER_NAME}-builder" \
        -v "$SCRIPT_DIR:/workspace" \
        "${IMAGE_NAME}:${IMAGE_TAG}" \
        -c "
            source /workspace/setup-env.sh /workspace/build-x86-openwrt
            bitbake ${target}
        "
}

clean() {
    print_step "Cleaning up Docker resources..."

    # Stop and remove container
    if docker ps -a --format '{{.Names}}' | grep -q "^${CONTAINER_NAME}$"; then
        print_info "Removing container '${CONTAINER_NAME}'..."
        docker rm -f "${CONTAINER_NAME}" 2>/dev/null || true
    fi

    if docker ps -a --format '{{.Names}}' | grep -q "^${CONTAINER_NAME}-builder$"; then
        print_info "Removing container '${CONTAINER_NAME}-builder'..."
        docker rm -f "${CONTAINER_NAME}-builder" 2>/dev/null || true
    fi

    # Remove image
    if image_exists; then
        print_info "Removing image '${IMAGE_NAME}:${IMAGE_TAG}'..."
        docker rmi "${IMAGE_NAME}:${IMAGE_TAG}" 2>/dev/null || true
    fi

    print_info "Cleanup complete."
}

show_help() {
    echo ""
    echo "OpenWrt-Yocto macOS Build Environment Setup"
    echo ""
    echo "Usage: ./setup-env-macos.sh [command]"
    echo ""
    echo "Commands:"
    echo "  setup        Build the Docker image (default action)"
    echo "  shell        Enter the interactive build container"
    echo "  build TARGET Run bitbake inside the container"
    echo "  clean        Remove Docker image and containers"
    echo "  help         Show this help message"
    echo ""
    echo "Examples:"
    echo "  ./setup-env-macos.sh                           # First-time setup"
    echo "  ./setup-env-macos.sh shell                     # Enter build shell"
    echo "  ./setup-env-macos.sh build openwrt-image-base  # Build image"
    echo "  ./setup-env-macos.sh clean                     # Cleanup"
    echo ""
    echo "Quick Start Workflow:"
    echo "  1. ./setup-env-macos.sh                        # Build Docker image"
    echo "  2. ./setup-env-macos.sh shell                  # Enter container"
    echo "  3. source ./setup-env.sh                       # Inside container: init env"
    echo "  4. bitbake openwrt-image-base                  # Inside container: build"
    echo ""
}

# ─── Main ────────────────────────────────────────────────────────────────────

main() {
    local cmd="${1:-setup}"

    case "$cmd" in
        setup)
            print_header
            check_prerequisites
            build_image
            echo ""
            print_info "Setup complete! Next steps:"
            echo ""
            echo "  1. Enter the build container:"
            echo "     ./setup-env-macos.sh shell"
            echo ""
            echo "  2. Inside the container, initialize the build:"
            echo "     source ./setup-env.sh"
            echo ""
            echo "  3. Build an image:"
            echo "     bitbake openwrt-image-base"
            echo ""
            ;;
        shell)
            print_header
            check_prerequisites
            enter_shell
            ;;
        build)
            print_header
            check_prerequisites
            run_bitbake "$2"
            ;;
        clean)
            print_header
            clean
            ;;
        help|--help|-h)
            print_header
            show_help
            ;;
        *)
            print_error "Unknown command: $cmd"
            show_help
            exit 1
            ;;
    esac
}

main "$@"