#!/bin/bash
# patch_rollback.sh - 企业级补丁包回滚脚本

set -euo pipefail
shopt -s nullglob extglob

# 脚本目录
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
CONFIG_FILE="${SCRIPT_DIR}/patch_config.sh"

# 颜色定义
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
PURPLE='\033[0;35m'
CYAN='\033[0;36m'
NC='\033[0m'

# 日志函数
log() {
    local level="$1"
    local message="$2"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')
    
    case "$level" in
        "INFO") color="$GREEN" ;;
        "WARN") color="$YELLOW" ;;
        "ERROR") color="$RED" ;;
        "DEBUG") color="$BLUE" ;;
        *) color="$NC" ;;
    esac
    
    echo -e "${color}[$timestamp] [$level]${NC} $message" | tee -a "$LOG_FILE"
}

info() { log "INFO" "$1"; }
warn() { log "WARN" "$1"; }
error() { log "ERROR" "$1"; }
debug() { log "DEBUG" "$1"; }

# 配置和初始化
load_config() {
    if [[ ! -f "$CONFIG_FILE" ]]; then
        error "配置文件不存在: $CONFIG_FILE"
        exit 1
    fi
    
    source "$CONFIG_FILE"
    info "配置文件加载完成"
    
    : ${LOG_LEVEL:="INFO"}
    : ${LOG_FILE:="/tmp/patch_rollback_$(date +%Y%m%d_%H%M%S).log"}
    : ${BACKUP_DIR:="/var/backups/patch"}
    : ${TEMP_DIR:="/tmp/patch_rollback_$$"}
    : ${ROLLBACK_INFO_FILE:="$BACKUP_DIR/rollback_info.json"}
}

setup_environment() {
    mkdir -p "$(dirname "$LOG_FILE")"
    mkdir -p "$TEMP_DIR"
    
    info "日志文件: $LOG_FILE"
    info "临时目录: $TEMP_DIR"
}

cleanup() {
    if [[ -d "$TEMP_DIR" ]]; then
        rm -rf "$TEMP_DIR"
        info "临时目录已清理: $TEMP_DIR"
    fi
}

trap cleanup EXIT

# 回滚点管理
get_available_rollback_points() {
    info "可用的回滚点:"
    
    if [[ ! -f "$ROLLBACK_INFO_FILE" ]]; then
        warn "未找到回滚点信息文件"
        return 1
    fi
    
    # 读取回滚点信息
    local patch_name=$(jq -r '.patch_name' "$ROLLBACK_INFO_FILE" 2>/dev/null || echo "")
    local apply_time=$(jq -r '.apply_time' "$ROLLBACK_INFO_FILE" 2>/dev/null || echo "")
    local backup_path=$(jq -r '.backup_path' "$ROLLBACK_INFO_FILE" 2>/dev/null || echo "")
    
    if [[ -n "$patch_name" && -n "$backup_path" && -f "$backup_path" ]]; then
        echo "1. $patch_name (应用时间: $apply_time)"
        echo "   备份文件: $backup_path"
        return 0
    else
        warn "回滚点信息不完整或备份文件不存在"
        return 1
    fi
}

# 验证回滚包
verify_rollback_package() {
    local rollback_path="$1"
    
    info "验证回滚包: $rollback_path"
    
    if [[ ! -f "$rollback_path" ]]; then
        error "回滚包不存在: $rollback_path"
        return 1
    fi
    
    if ! tar -tzf "$rollback_path" >/dev/null 2>&1; then
        error "回滚包损坏或格式错误"
        return 1
    fi
    
    info "✅ 回滚包验证通过"
    return 0
}

# 回滚执行函数
perform_rollback() {
    local rollback_path="$1"
    local dry_run="${2:-false}"
    
    info "开始执行回滚: $rollback_path"
    
    # 验证回滚包
    if ! verify_rollback_package "$rollback_path"; then
        return 1
    fi
    
    # 解压回滚包
    local extract_dir="$TEMP_DIR/rollback_extract"
    if ! tar -xzf "$rollback_path" -C "$extract_dir"; then
        error "回滚包解压失败"
        return 1
    fi
    info "✅ 回滚包解压完成"
    
    # 如果是干跑模式，只显示将要回滚的文件
    if [[ "$dry_run" == "true" ]]; then
        info "干跑模式: 显示将要回滚的文件"
        find "$extract_dir" -type f | while read file; do
            local relative_path="${file#$extract_dir/}"
            local target_file="/$relative_path"
            echo "📁 将回滚: $relative_path -> $target_file"
        done
        return 0
    fi
    
    # 执行实际回滚
    if execute_file_rollback "$extract_dir"; then
        info "✅ 回滚执行完成"
        
        # 清理回滚点
        cleanup_rollback_point
        
        send_rollback_notification "success" "$rollback_path" "回滚成功"
        return 0
    else
        error "❌ 回滚执行失败"
        send_rollback_notification "failure" "$rollback_path" "回滚失败"
        return 1
    fi
}

execute_file_rollback() {
    local extract_dir="$1"
    
    info "开始执行文件回滚..."
    
    local rollback_count=0
    local error_count=0
    
    # 遍历回滚包中的所有文件
    find "$extract_dir" -type f | while read backup_file; do
        local relative_path="${backup_file#$extract_dir/}"
        local target_file="/$relative_path"
        local target_dir=$(dirname "$target_file")
        
        # 创建目标目录
        mkdir -p "$target_dir"
        
        # 备份当前文件（如果存在）
        if [[ -f "$target_file" ]]; then
            local current_backup="$TEMP_DIR/current_backup/$relative_path"
            mkdir -p "$(dirname "$current_backup")"
            cp -p "$target_file" "$current_backup"
            debug "备份当前文件: $target_file"
        fi
        
        # 恢复文件
        if cp -p "$backup_file" "$target_file"; then
            info "✅ 回滚文件: $relative_path"
            ((rollback_count++))
        else
            error "❌ 回滚失败: $relative_path"
            ((error_count++))
        fi
    done
    
    info "回滚完成: $rollback_count 个文件成功, $error_count 个文件失败"
    
    if [[ $error_count -gt 0 ]]; then
        return 1
    fi
    return 0
}

# 清理回滚点
cleanup_rollback_point() {
    if [[ -f "$ROLLBACK_INFO_FILE" ]]; then
        mv "$ROLLBACK_INFO_FILE" "$ROLLBACK_INFO_FILE.bak"
        info "回滚点已清理: $ROLLBACK_INFO_FILE -> $ROLLBACK_INFO_FILE.bak"
    fi
}

# 通知函数
send_rollback_notification() {
    local status="$1"
    local rollback_path="$2"
    local message="$3"
    
    if [[ "$NOTIFICATIONS_ENABLED" != "true" ]]; then
        return 0
    fi
    
    case "$status" in
        "success")
            local subject="补丁回滚成功"
            local color="#2ecc71"
            ;;
        "failure")
            local subject="补丁回滚失败"
            local color="#e74c3c"
            ;;
        *)
            local subject="补丁回滚通知"
            local color="#95a5a6"
            ;;
    esac
    
    # Slack通知
    if [[ -n "$SLACK_WEBHOOK" ]]; then
        send_slack_rollback_notification "$subject" "$message" "$color" "$rollback_path"
    fi
}

send_slack_rollback_notification() {
    local subject="$1"
    local message="$2"
    local color="$3"
    local rollback_path="$4"
    
    local payload=$(cat << EOF
{
    "attachments": [
        {
            "color": "$color",
            "title": "$subject",
            "text": "$message",
            "fields": [
                {
                    "title": "回滚包",
                    "value": "$(basename "$rollback_path")",
                    "short": true
                },
                {
                    "title": "回滚时间",
                    "value": "$(date)",
                    "short": true
                },
                {
                    "title": "回滚主机",
                    "value": "$(hostname)",
                    "short": true
                }
            ]
        }
    ]
}
EOF
)
    
    if command -v curl >/dev/null 2>&1; then
        curl -s -X POST -H 'Content-type: application/json' \
            --data "$payload" "$SLACK_WEBHOOK" >/dev/null && \
        info "Slack通知发送成功"
    fi
}

# 主回滚函数
rollback_patch() {
    local rollback_path="${1:-}"
    local dry_run="${2:-false}"
    
    # 如果没有指定回滚包，使用最近的
    if [[ -z "$rollback_path" ]]; then
        info "未指定回滚包，查找最近的回滚点..."
        if get_available_rollback_points; then
            if [[ -f "$ROLLBACK_INFO_FILE" ]]; then
                rollback_path=$(jq -r '.backup_path' "$ROLLBACK_INFO_FILE")
                info "使用回滚包: $rollback_path"
            else
                error "未找到可用的回滚点"
                return 1
            fi
        else
            error "无法获取回滚点信息"
            return 1
        fi
    fi
    
    # 执行回滚
    if perform_rollback "$rollback_path" "$dry_run"; then
        info "🎉 回滚操作成功完成"
        return 0
    else
        error "💥 回滚操作失败"
        return 1
    fi
}

# 主函数
main() {
    local rollback_path="${1:-}"
    local dry_run="${2:-false}"
    
    # 加载配置
    load_config
    
    # 设置环境
    setup_environment
    
    # 显示使用信息
    if [[ "$1" == "-h" ]] || [[ "$1" == "--help" ]]; then
        echo "用法: $0 [回滚包路径] [dry-run]"
        echo "示例:"
        echo "  $0                                  # 使用最近的回滚点"
        echo "  $0 /var/backups/patch/backup_xxx.tar.gz  # 指定回滚包"
        echo "  $0 /path/to/backup.tar.gz dry-run   # 干跑模式"
        exit 0
    fi
    
    # 执行回滚
    if rollback_patch "$rollback_path" "$dry_run"; then
        exit 0
    else
        exit 1
    fi
}

# 异常处理
trap 'error "脚本执行中断"; cleanup; exit 1' INT TERM

main "$@"