#!/bin/env bash

# Docker 安装脚本
# 支持中国大陆和海外环境

set -euo pipefail

readonly SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
readonly LOG_FILE="${SCRIPT_DIR}/docker_install.log"
readonly DAEMON_JSON="/etc/docker/daemon.json"
readonly BACKUP_FILE="${DAEMON_JSON}.backup"

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

# 日志函数
log() {
    echo -e "${GREEN}[$(date +'%Y-%m-%d %H:%M:%S')]${NC} $1" | tee -a "$LOG_FILE"
}

log_info() {
    echo -e "${BLUE}[INFO]${NC} $1" | tee -a "$LOG_FILE"
}

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

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

# 检测地区
detect_region() {
    local country
    country=$(curl -s --connect-timeout 5 --max-time 10 ipinfo.io/country 2>/dev/null || echo "")
    [[ "$country" == "CN" ]]
}

# 检查Docker版本
check_docker_version() {
    if ! command -v docker &>/dev/null; then
        return 1
    fi

    local version
    version=$(docker --version 2>/dev/null | grep -oE '[0-9]+\.[0-9]+' | head -n1)
    local major="${version%%.*}"
    
    if [[ ${major:-0} -lt 20 ]]; then
        log_warn "Docker版本过低 (${version})，建议升级到20.x或更高版本"
    else
        log_info "检测到Docker版本: ${version}"
    fi
    
    return 0
}

# 创建daemon.json配置
create_daemon_json() {
    local accelerator_url="${1:-}"
    
    if [[ -n "$accelerator_url" ]]; then
        log_info "配置Docker镜像加速器: $accelerator_url"
        cat > "$DAEMON_JSON" << EOF
{
    "registry-mirrors": ["$accelerator_url"],
    "log-driver": "json-file",
    "log-opts": {
        "max-size": "100m",
        "max-file": "3"
    },
    "storage-driver": "overlay2"
}
EOF
    else
        cat > "$DAEMON_JSON" << EOF
{
    "log-driver": "json-file",
    "log-opts": {
        "max-size": "100m",
        "max-file": "3"
    },
    "storage-driver": "overlay2"
}
EOF
    fi
}

# 配置加速器
configure_accelerator() {
    if ! detect_region; then
        log_info "非中国大陆地区，跳过镜像加速器配置"
        return 0
    fi

    echo -n "是否配置Docker镜像加速器？(y/N): "
    read -r choice
    
    case "$choice" in
        [yY]|[yY][eE][sS])
            local accelerator_url=""
            
            # 测试腾讯云镜像可用性
            if ping -c 1 -W 3 mirror.ccs.tencentyun.com &>/dev/null; then
                accelerator_url="https://mirror.ccs.tencentyun.com"
            else
                # 备选阿里云镜像
                accelerator_url="https://registry.cn-hangzhou.aliyuncs.com"
            fi
            
            # 备份现有配置
            [[ -f "$DAEMON_JSON" ]] && cp "$DAEMON_JSON" "$BACKUP_FILE"
            
            # 创建配置目录
            mkdir -p "$(dirname "$DAEMON_JSON")"
            
            # 创建新配置
            create_daemon_json "$accelerator_url"
            
            # 重启Docker服务
            log_info "重启Docker服务..."
            systemctl daemon-reload
            systemctl restart docker
            
            log "Docker镜像加速器配置完成"
            ;;
        *)
            log_info "跳过镜像加速器配置"
            ;;
    esac
}

# 获取最快的Docker安装源
get_fastest_source() {
    local sources=(
        "https://mirrors.aliyun.com/docker-ce"
        "https://mirrors.tencent.com/docker-ce"
        "https://mirrors.163.com/docker-ce"
    )
    
    local fastest_source="${sources[0]}"
    local min_time=99999
    
    for source in "${sources[@]}"; do
        local response_time
        response_time=$(curl -o /dev/null -s -w '%{time_total}\n' -m 3 "$source" 2>/dev/null || echo "99999")
        
        if (( $(echo "$response_time < $min_time" | bc -l 2>/dev/null || echo 0) )); then
            min_time=$response_time
            fastest_source=$source
        fi
    done
    
    echo "$fastest_source"
}

# 下载Docker安装脚本
download_docker_script() {
    local scripts=(
        "https://get.docker.com"
        "https://cdn.jsdelivr.net/gh/docker/docker-install@master/install.sh"
        "https://fastly.jsdelivr.net/gh/docker/docker-install@master/install.sh"
    )
    
    for script_url in "${scripts[@]}"; do
        log_info "尝试从 $script_url 下载安装脚本..."
        
        if curl -fsSL --connect-timeout 10 --max-time 30 "$script_url" -o get-docker.sh; then
            log "下载成功: $script_url"
            return 0
        else
            log_warn "下载失败: $script_url"
        fi
    done
    
    log_error "所有下载尝试均失败"
    return 1
}

# 安装Docker
install_docker() {
    log_info "开始安装Docker..."
    
    if detect_region; then
        log_info "检测到中国大陆地区，使用国内镜像源"
        local fastest_source
        fastest_source=$(get_fastest_source)
        export DOWNLOAD_URL="$fastest_source"
        log_info "选择最快源: $fastest_source"
    else
        log_info "使用官方源"
        export DOWNLOAD_URL="https://download.docker.com"
    fi
    
    # 下载安装脚本
    if ! download_docker_script; then
        log_error "无法下载Docker安装脚本"
        return 1
    fi
    
    # 执行安装
    log_info "执行Docker安装..."
    if sh get-docker.sh 2>&1 | tee -a "$LOG_FILE"; then
        log "Docker安装成功"
    else
        log_error "Docker安装失败"
        return 1
    fi
    
    # 清理安装脚本
    rm -f get-docker.sh
    
    # 启动并启用Docker服务
    log_info "启动Docker服务..."
    systemctl enable docker
    systemctl start docker
    
    # 验证安装
    if docker --version &>/dev/null; then
        log "Docker安装验证成功"
        docker --version | tee -a "$LOG_FILE"
        return 0
    else
        log_error "Docker安装验证失败"
        return 1
    fi
}

# 主函数
main() {
    log "开始Docker安装检查..."
    
    # 检查是否已安装Docker
    if check_docker_version; then
        log_info "Docker已安装"
        configure_accelerator
        return 0
    fi
    
    # 确认安装
    echo -n "Docker未安装，是否现在安装？(y/N): "
    read -r install_choice
    
    case "$install_choice" in
        [yY]|[yY][eE][sS])
            if install_docker; then
                configure_accelerator
                log "Docker安装和配置完成！"
            else
                log_error "Docker安装失败，请检查日志: $LOG_FILE"
                exit 1
            fi
            ;;
        *)
            log_info "取消安装"
            exit 0
            ;;
    esac
}

# 检查root权限
if [[ $EUID -ne 0 ]]; then
    log_error "此脚本需要root权限运行"
    exit 1
fi

# 执行主函数
main "$@"