#!/bin/bash
#
# Meeting Assistant Backend - 一鍵設置與啟動腳本
# 自動安裝依賴、設置環境並啟動後端服務
#

set -e

# 顏色定義
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
CYAN='\033[0;36m'
NC='\033[0m' # No Color

# 專案路徑
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
BACKEND_DIR="$PROJECT_DIR/backend"
SIDECAR_DIR="$PROJECT_DIR/sidecar"

# 預設配置
DEFAULT_PORT=8000
DEFAULT_HOST="0.0.0.0"

# 函數：印出訊息
log_info() {
    echo -e "${BLUE}[INFO]${NC} $1"
}

log_success() {
    echo -e "${GREEN}[OK]${NC} $1"
}

log_warn() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

log_step() {
    echo -e "${CYAN}[STEP]${NC} $1"
}

# 函數：顯示標題
show_banner() {
    echo ""
    echo -e "${CYAN}=========================================="
    echo "  Meeting Assistant Backend Setup"
    echo "  一鍵設置與啟動腳本"
    echo -e "==========================================${NC}"
    echo ""
}

# 函數：檢查 Python 版本
check_python() {
    log_step "檢查 Python 環境..."

    # 嘗試不同的 Python 命令
    local python_cmd=""
    for cmd in python3 python; do
        if command -v $cmd &> /dev/null; then
            local version=$($cmd -c 'import sys; print(f"{sys.version_info.major}.{sys.version_info.minor}")')
            local major=$($cmd -c 'import sys; print(sys.version_info.major)')
            local minor=$($cmd -c 'import sys; print(sys.version_info.minor)')

            if [ "$major" -ge 3 ] && [ "$minor" -ge 10 ]; then
                python_cmd=$cmd
                log_success "Python $version ($cmd)"
                break
            fi
        fi
    done

    if [ -z "$python_cmd" ]; then
        log_error "需要 Python 3.10 或更高版本"
        log_info "請安裝 Python: https://www.python.org/downloads/"
        exit 1
    fi

    echo "$python_cmd"
}

# 函數：設置後端虛擬環境
setup_backend_venv() {
    local python_cmd=$1

    log_step "設置後端虛擬環境..."

    cd "$BACKEND_DIR"

    if [ ! -d "venv" ]; then
        log_info "創建虛擬環境..."
        $python_cmd -m venv venv
        log_success "虛擬環境已創建"
    else
        log_info "虛擬環境已存在"
    fi

    # 啟動虛擬環境並安裝依賴
    log_info "安裝後端依賴..."

    if [[ "$OSTYPE" == "msys" ]] || [[ "$OSTYPE" == "win32" ]] || [[ "$OSTYPE" == "cygwin" ]]; then
        # Windows
        source venv/Scripts/activate
    else
        # Linux/Mac
        source venv/bin/activate
    fi

    pip install --upgrade pip -q
    pip install -r requirements.txt -q

    log_success "後端依賴安裝完成"
}

# 函數：設置 Sidecar 虛擬環境
setup_sidecar_venv() {
    local python_cmd=$1

    log_step "設置 Sidecar 虛擬環境..."

    cd "$SIDECAR_DIR"

    if [ ! -d "venv" ]; then
        log_info "創建 Sidecar 虛擬環境..."
        $python_cmd -m venv venv
        log_success "Sidecar 虛擬環境已創建"
    else
        log_info "Sidecar 虛擬環境已存在"
    fi

    # 啟動虛擬環境並安裝依賴
    log_info "安裝 Sidecar 依賴 (這可能需要幾分鐘)..."

    if [[ "$OSTYPE" == "msys" ]] || [[ "$OSTYPE" == "win32" ]] || [[ "$OSTYPE" == "cygwin" ]]; then
        source venv/Scripts/activate
    else
        source venv/bin/activate
    fi

    pip install --upgrade pip -q
    pip install -r requirements.txt -q

    log_success "Sidecar 依賴安裝完成"
}

# 函數：設置環境變數檔案
setup_env_file() {
    log_step "檢查環境變數配置..."

    cd "$BACKEND_DIR"

    if [ ! -f ".env" ]; then
        if [ -f ".env.example" ]; then
            cp .env.example .env
            log_warn "已從 .env.example 創建 .env 檔案"
            log_warn "請編輯 $BACKEND_DIR/.env 設置資料庫和 API 密鑰"
        else
            log_error "找不到 .env.example 檔案"
            exit 1
        fi
    else
        log_success "環境變數檔案已存在"
    fi
}

# 函數：檢查 port 是否被佔用
check_port() {
    local port=$1
    if command -v lsof &> /dev/null; then
        if lsof -i :$port > /dev/null 2>&1; then
            return 0  # port 被佔用
        fi
    elif command -v netstat &> /dev/null; then
        if netstat -tuln | grep -q ":$port "; then
            return 0
        fi
    fi
    return 1  # port 可用
}

# 函數：釋放 port
release_port() {
    local port=$1
    if check_port $port; then
        log_warn "Port $port 被佔用，嘗試釋放..."
        if command -v lsof &> /dev/null; then
            local pid=$(lsof -t -i :$port 2>/dev/null)
            if [ -n "$pid" ]; then
                kill -9 $pid 2>/dev/null || true
                sleep 1
                log_success "Port $port 已釋放"
            fi
        else
            log_error "無法釋放 port，請手動關閉佔用 $port 的程序"
            exit 1
        fi
    fi
}

# 函數：啟動後端服務
start_backend() {
    local host=${1:-$DEFAULT_HOST}
    local port=${2:-$DEFAULT_PORT}
    local mode=${3:-"foreground"}  # foreground 或 background

    log_step "啟動後端服務..."

    cd "$BACKEND_DIR"

    # 載入環境變數
    if [ -f ".env" ]; then
        export $(grep -v '^#' .env | grep -v '^$' | xargs)
    fi

    # 使用 .env 中的配置或預設值
    host=${BACKEND_HOST:-$host}
    port=${BACKEND_PORT:-$port}

    # 釋放 port
    release_port $port

    # 啟動虛擬環境
    if [[ "$OSTYPE" == "msys" ]] || [[ "$OSTYPE" == "win32" ]] || [[ "$OSTYPE" == "cygwin" ]]; then
        source venv/Scripts/activate
    else
        source venv/bin/activate
    fi

    echo ""
    log_success "後端服務準備就緒！"
    echo ""
    echo -e "${CYAN}=========================================="
    echo "  服務資訊"
    echo -e "==========================================${NC}"
    echo ""
    echo "  API 地址: http://localhost:$port"
    echo "  API 文件: http://localhost:$port/docs"
    echo "  健康檢查: http://localhost:$port/api/health"
    echo ""
    echo "  按 Ctrl+C 停止服務"
    echo ""

    if [ "$mode" = "background" ]; then
        nohup uvicorn app.main:app --host $host --port $port --reload > "$PROJECT_DIR/backend.log" 2>&1 &
        local pid=$!
        echo $pid > "$PROJECT_DIR/.backend_pid"
        log_success "後端服務已在背景啟動 (PID: $pid)"
        log_info "查看日誌: tail -f $PROJECT_DIR/backend.log"
    else
        # 前景執行
        uvicorn app.main:app --host $host --port $port --reload
    fi
}

# 函數：顯示幫助
show_help() {
    echo ""
    echo "Meeting Assistant Backend - 一鍵設置與啟動腳本"
    echo ""
    echo "用法: $0 [命令] [選項]"
    echo ""
    echo "命令:"
    echo "  setup       僅設置環境 (安裝依賴)"
    echo "  start       設置並啟動後端服務 (前景執行)"
    echo "  start-bg    設置並啟動後端服務 (背景執行)"
    echo "  stop        停止背景執行的後端服務"
    echo "  help        顯示此幫助訊息"
    echo ""
    echo "選項:"
    echo "  --port PORT   服務端口 (預設: $DEFAULT_PORT)"
    echo "  --host HOST   綁定地址 (預設: $DEFAULT_HOST)"
    echo "  --no-sidecar  不安裝 Sidecar 依賴"
    echo ""
    echo "範例:"
    echo "  $0 start              # 設置並啟動服務"
    echo "  $0 start --port 8080  # 使用自訂端口"
    echo "  $0 setup              # 僅安裝依賴"
    echo "  $0 start-bg           # 背景執行"
    echo ""
}

# 函數：停止背景服務
stop_backend() {
    log_step "停止後端服務..."

    if [ -f "$PROJECT_DIR/.backend_pid" ]; then
        local pid=$(cat "$PROJECT_DIR/.backend_pid")
        if kill -0 $pid 2>/dev/null; then
            kill $pid
            rm -f "$PROJECT_DIR/.backend_pid"
            log_success "後端服務已停止 (PID: $pid)"
        else
            rm -f "$PROJECT_DIR/.backend_pid"
            log_warn "服務已經停止"
        fi
    else
        # 嘗試通過 port 查找
        if command -v lsof &> /dev/null; then
            local port=${BACKEND_PORT:-$DEFAULT_PORT}
            local pid=$(lsof -t -i :$port 2>/dev/null)
            if [ -n "$pid" ]; then
                kill $pid 2>/dev/null || true
                log_success "已停止 port $port 上的服務"
            else
                log_warn "沒有找到運行中的後端服務"
            fi
        fi
    fi
}

# 主程式
main() {
    local command=${1:-"start"}
    local port=$DEFAULT_PORT
    local host=$DEFAULT_HOST
    local setup_sidecar=true

    # 解析參數
    shift || true
    while [[ $# -gt 0 ]]; do
        case $1 in
            --port)
                port="$2"
                shift 2
                ;;
            --host)
                host="$2"
                shift 2
                ;;
            --no-sidecar)
                setup_sidecar=false
                shift
                ;;
            *)
                log_error "未知參數: $1"
                show_help
                exit 1
                ;;
        esac
    done

    case $command in
        setup)
            show_banner
            local python_cmd=$(check_python)
            setup_backend_venv "$python_cmd"
            if [ "$setup_sidecar" = true ]; then
                setup_sidecar_venv "$python_cmd"
            fi
            setup_env_file
            echo ""
            log_success "環境設置完成！"
            echo ""
            log_info "啟動服務: $0 start"
            ;;
        start)
            show_banner
            local python_cmd=$(check_python)
            setup_backend_venv "$python_cmd"
            setup_env_file
            start_backend "$host" "$port" "foreground"
            ;;
        start-bg)
            show_banner
            local python_cmd=$(check_python)
            setup_backend_venv "$python_cmd"
            setup_env_file
            start_backend "$host" "$port" "background"
            ;;
        stop)
            stop_backend
            ;;
        help|--help|-h)
            show_help
            ;;
        *)
            log_error "未知命令: $command"
            show_help
            exit 1
            ;;
    esac
}

# 捕捉中斷信號
trap 'echo ""; log_info "收到中斷信號"; exit 0' INT TERM

# 執行主程式
main "$@"