#!/bin/bash
#
# Meeting Assistant Backend - Deployment Script
# 用於在 1Panel 或其他 Linux 服務器上部署後端服務
#

set -e

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

# 預設配置
DEFAULT_INSTALL_DIR="/opt/meeting-assistant"
DEFAULT_USER="meeting"
DEFAULT_PORT="8000"

# 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"
}

# 函數：顯示幫助
show_help() {
    echo ""
    echo "Meeting Assistant Backend 部署腳本"
    echo ""
    echo "用法: $0 [命令] [選項]"
    echo ""
    echo "命令:"
    echo "  install       安裝後端服務"
    echo "  update        更新後端服務"
    echo "  uninstall     移除後端服務"
    echo "  status        顯示服務狀態"
    echo "  logs          顯示服務日誌"
    echo "  help          顯示此幫助訊息"
    echo ""
    echo "選項:"
    echo "  --dir DIR     安裝目錄 (預設: $DEFAULT_INSTALL_DIR)"
    echo "  --user USER   運行服務的用戶 (預設: $DEFAULT_USER)"
    echo "  --port PORT   服務端口 (預設: $DEFAULT_PORT)"
    echo ""
    echo "範例:"
    echo "  $0 install --port 8080"
    echo "  $0 update"
    echo "  $0 status"
    echo ""
}

# 函數：檢查是否為 root
check_root() {
    if [ "$EUID" -ne 0 ]; then
        log_error "請使用 root 權限執行此腳本"
        log_info "使用: sudo $0 $@"
        exit 1
    fi
}

# 函數：檢查依賴
check_dependencies() {
    log_info "檢查系統依賴..."

    local missing=()

    # 檢查 Python 3.10+
    if command -v python3 &> /dev/null; then
        local py_version=$(python3 -c 'import sys; print(f"{sys.version_info.major}.{sys.version_info.minor}")')
        log_success "Python: $py_version"
    else
        missing+=("python3")
    fi

    # 檢查 pip
    if ! command -v pip3 &> /dev/null; then
        missing+=("python3-pip")
    fi

    # 檢查 venv
    if ! python3 -c "import venv" &> /dev/null 2>&1; then
        missing+=("python3-venv")
    fi

    if [ ${#missing[@]} -gt 0 ]; then
        log_error "缺少依賴: ${missing[*]}"
        log_info "請先安裝: apt install ${missing[*]}"
        exit 1
    fi

    log_success "所有依賴已滿足"
}

# 函數：創建系統用戶
create_user() {
    local username=$1

    if id "$username" &>/dev/null; then
        log_info "用戶 $username 已存在"
    else
        log_info "創建系統用戶: $username"
        useradd --system --no-create-home --shell /bin/false "$username"
        log_success "用戶 $username 已創建"
    fi
}

# 函數：安裝後端
install_backend() {
    local install_dir=$1
    local username=$2
    local port=$3

    log_info "開始安裝 Meeting Assistant Backend..."
    log_info "安裝目錄: $install_dir"
    log_info "服務用戶: $username"
    log_info "服務端口: $port"
    echo ""

    # 檢查依賴
    check_dependencies

    # 創建用戶
    create_user "$username"

    # 創建目錄
    log_info "創建安裝目錄..."
    mkdir -p "$install_dir"
    mkdir -p "$install_dir/logs"
    mkdir -p "$install_dir/templates"
    mkdir -p "$install_dir/records"

    # 複製後端代碼
    log_info "複製後端代碼..."
    local script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
    local source_dir="$(dirname "$script_dir")/backend"

    if [ ! -d "$source_dir" ]; then
        log_error "找不到後端源碼目錄: $source_dir"
        exit 1
    fi

    cp -r "$source_dir/app" "$install_dir/"
    cp "$source_dir/requirements.txt" "$install_dir/"

    # 複製 .env.example 如果 .env 不存在
    if [ ! -f "$install_dir/.env" ]; then
        if [ -f "$source_dir/.env.example" ]; then
            cp "$source_dir/.env.example" "$install_dir/.env"
            log_warn "已創建 .env 檔案，請編輯配置: $install_dir/.env"
        fi
    fi

    # 複製模板檔案
    if [ -d "$source_dir/templates" ]; then
        cp -r "$source_dir/templates/"* "$install_dir/templates/" 2>/dev/null || true
    fi

    # 創建虛擬環境
    log_info "創建 Python 虛擬環境..."
    python3 -m venv "$install_dir/venv"

    # 安裝依賴
    log_info "安裝 Python 依賴..."
    "$install_dir/venv/bin/pip" install --upgrade pip
    "$install_dir/venv/bin/pip" install -r "$install_dir/requirements.txt"

    # 更新 .env 中的端口配置
    if [ -f "$install_dir/.env" ]; then
        sed -i "s/^BACKEND_PORT=.*/BACKEND_PORT=$port/" "$install_dir/.env"
    fi

    # 設置權限
    log_info "設置檔案權限..."
    chown -R "$username:$username" "$install_dir"
    chmod 750 "$install_dir"
    chmod 640 "$install_dir/.env" 2>/dev/null || true

    # 創建 systemd 服務
    create_systemd_service "$install_dir" "$username" "$port"

    # 啟動服務
    log_info "啟動服務..."
    systemctl daemon-reload
    systemctl enable meeting-assistant-backend
    systemctl start meeting-assistant-backend

    # 等待啟動
    sleep 3

    # 檢查狀態
    if systemctl is-active --quiet meeting-assistant-backend; then
        log_success "Meeting Assistant Backend 安裝成功！"
        echo ""
        echo "=========================================="
        echo "  安裝完成"
        echo "=========================================="
        echo ""
        echo "  服務狀態: systemctl status meeting-assistant-backend"
        echo "  查看日誌: journalctl -u meeting-assistant-backend -f"
        echo "  API 地址: http://localhost:$port"
        echo "  API 文件: http://localhost:$port/docs"
        echo ""
        echo "  配置檔案: $install_dir/.env"
        echo "  請確保已正確配置數據庫和 API 密鑰"
        echo ""
    else
        log_error "服務啟動失敗，請檢查日誌"
        journalctl -u meeting-assistant-backend --no-pager -n 20
        exit 1
    fi
}

# 函數：創建 systemd 服務檔案
create_systemd_service() {
    local install_dir=$1
    local username=$2
    local port=$3

    log_info "創建 systemd 服務..."

    cat > /etc/systemd/system/meeting-assistant-backend.service << EOF
[Unit]
Description=Meeting Assistant Backend API
After=network.target

[Service]
Type=simple
User=$username
Group=$username
WorkingDirectory=$install_dir
Environment="PATH=$install_dir/venv/bin"
EnvironmentFile=$install_dir/.env
ExecStart=$install_dir/venv/bin/uvicorn app.main:app --host 0.0.0.0 --port $port
Restart=always
RestartSec=5
StandardOutput=journal
StandardError=journal

# Security hardening
NoNewPrivileges=true
ProtectSystem=strict
ProtectHome=true
ReadWritePaths=$install_dir/logs $install_dir/records $install_dir/templates
PrivateTmp=true

[Install]
WantedBy=multi-user.target
EOF

    log_success "systemd 服務已創建"
}

# 函數：更新後端
update_backend() {
    local install_dir=$1

    log_info "更新 Meeting Assistant Backend..."

    if [ ! -d "$install_dir" ]; then
        log_error "安裝目錄不存在: $install_dir"
        exit 1
    fi

    # 停止服務
    log_info "停止服務..."
    systemctl stop meeting-assistant-backend || true

    # 備份配置
    log_info "備份配置..."
    cp "$install_dir/.env" "$install_dir/.env.backup" 2>/dev/null || true

    # 複製新代碼
    local script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
    local source_dir="$(dirname "$script_dir")/backend"

    log_info "更新代碼..."
    rm -rf "$install_dir/app"
    cp -r "$source_dir/app" "$install_dir/"
    cp "$source_dir/requirements.txt" "$install_dir/"

    # 更新依賴
    log_info "更新依賴..."
    "$install_dir/venv/bin/pip" install -r "$install_dir/requirements.txt"

    # 恢復配置
    if [ -f "$install_dir/.env.backup" ]; then
        mv "$install_dir/.env.backup" "$install_dir/.env"
    fi

    # 重新設置權限
    local username=$(stat -c '%U' "$install_dir")
    chown -R "$username:$username" "$install_dir"

    # 重啟服務
    log_info "重啟服務..."
    systemctl daemon-reload
    systemctl start meeting-assistant-backend

    sleep 2

    if systemctl is-active --quiet meeting-assistant-backend; then
        log_success "更新完成！"
    else
        log_error "服務重啟失敗"
        exit 1
    fi
}

# 函數：移除後端
uninstall_backend() {
    local install_dir=$1

    log_warn "即將移除 Meeting Assistant Backend"
    read -p "確定要繼續嗎？(y/N) " confirm

    if [ "$confirm" != "y" ] && [ "$confirm" != "Y" ]; then
        log_info "取消移除"
        exit 0
    fi

    # 停止並禁用服務
    log_info "停止服務..."
    systemctl stop meeting-assistant-backend 2>/dev/null || true
    systemctl disable meeting-assistant-backend 2>/dev/null || true

    # 刪除 systemd 服務
    log_info "移除 systemd 服務..."
    rm -f /etc/systemd/system/meeting-assistant-backend.service
    systemctl daemon-reload

    # 詢問是否刪除數據
    read -p "是否刪除安裝目錄 $install_dir？(y/N) " delete_dir
    if [ "$delete_dir" = "y" ] || [ "$delete_dir" = "Y" ]; then
        log_info "刪除安裝目錄..."
        rm -rf "$install_dir"
    else
        log_info "保留安裝目錄: $install_dir"
    fi

    log_success "Meeting Assistant Backend 已移除"
}

# 函數：顯示狀態
show_status() {
    echo ""
    echo "=========================================="
    echo "  Meeting Assistant Backend 狀態"
    echo "=========================================="
    echo ""

    if systemctl is-active --quiet meeting-assistant-backend; then
        log_success "服務狀態: 運行中"
        systemctl status meeting-assistant-backend --no-pager | grep -E "(Active|Main PID|Memory|CPU)"
    else
        log_warn "服務狀態: 未運行"
    fi

    echo ""
}

# 函數：顯示日誌
show_logs() {
    journalctl -u meeting-assistant-backend -f
}

# 解析參數
INSTALL_DIR=$DEFAULT_INSTALL_DIR
SERVICE_USER=$DEFAULT_USER
SERVICE_PORT=$DEFAULT_PORT
COMMAND=""

while [[ $# -gt 0 ]]; do
    case $1 in
        install|update|uninstall|status|logs|help)
            COMMAND=$1
            shift
            ;;
        --dir)
            INSTALL_DIR="$2"
            shift 2
            ;;
        --user)
            SERVICE_USER="$2"
            shift 2
            ;;
        --port)
            SERVICE_PORT="$2"
            shift 2
            ;;
        *)
            log_error "未知參數: $1"
            show_help
            exit 1
            ;;
    esac
done

# 執行命令
case $COMMAND in
    install)
        check_root
        install_backend "$INSTALL_DIR" "$SERVICE_USER" "$SERVICE_PORT"
        ;;
    update)
        check_root
        update_backend "$INSTALL_DIR"
        ;;
    uninstall)
        check_root
        uninstall_backend "$INSTALL_DIR"
        ;;
    status)
        show_status
        ;;
    logs)
        show_logs
        ;;
    help|"")
        show_help
        ;;
    *)
        log_error "未知命令: $COMMAND"
        show_help
        exit 1
        ;;
esac