#!/bin/bash

# ============================================
# LinkShare Blog - 数据库恢复脚本
# ============================================
# 用途: 从备份恢复 PostgreSQL 数据库
# 用法: ./scripts/restore.sh <backup_file> [options]
# 示例: ./scripts/restore.sh daily_20260328.sql.gz

set -e

# 配置
DB_CONTAINER="blog-postgres"
DB_NAME="linkshare"
DB_USER="blog"

# 颜色定义
GREEN='\033[0;32m'
RED='\033[0;31m'
YELLOW='\033[1;33m'
NC='\033[0m'

log_info() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

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

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

# 显示用法
show_usage() {
    echo "用法: $0 <backup_file> [options]"
    echo ""
    echo "参数:"
    echo "  backup_file       备份文件路径 (必需)"
    echo ""
    echo "选项:"
    echo "  --drop           恢复前删除现有数据库 (危险!)"
    echo "  --dry-run        仅验证备份文件，不执行恢复"
    echo "  --help           显示此帮助信息"
    echo ""
    echo "示例:"
    echo "  $0 daily_20260328.sql.gz              # 恢复备份"
    echo "  $0 daily_20260328.sql.gz --drop      # 删除并恢复"
    echo "  $0 daily_20260328.sql.gz --dry-run   # 验证备份"
    echo ""
    echo "可用备份:"
    ls -1 backups/*.sql.gz 2>/dev/null || echo "  (无备份文件)"
}

# 检查参数
if [ $# -lt 1 ] || [ "$1" = "--help" ]; then
    show_usage
    exit 1
fi

BACKUP_FILE=$1
shift

# 解析选项
DROP_DB=false
DRY_RUN=false

while [[ $# -gt 0 ]]; do
    case $1 in
        --drop)
            DROP_DB=true
            shift
            ;;
        --dry-run)
            DRY_RUN=true
            shift
            ;;
        *)
            log_error "未知选项: $1"
            show_usage
            exit 1
            ;;
    esac
done

# 检查备份文件
if [ ! -f "$BACKUP_FILE" ]; then
    log_error "备份文件不存在: $BACKUP_FILE"
    exit 1
fi

# 验证备份文件
log_info "验证备份文件..."
if gzip -t "$BACKUP_FILE" 2>/dev/null; then
    log_info "✓ 备份文件完整性检查通过"
else
    log_error "备份文件损坏或不是有效的 gzip 文件"
    exit 1
fi

#  dry-run 模式
if [ "$DRY_RUN" = true ]; then
    log_info "Dry-run 模式: 不执行恢复"
    log_info "备份信息:"
    ls -lh "$BACKUP_FILE"
    gzip -dc "$BACKUP_FILE" | head -n 20
    log_info "备份文件前20行预览完成"
    exit 0
fi

# 检查数据库容器
if ! docker ps | grep -q "$DB_CONTAINER"; then
    log_error "数据库容器 '$DB_CONTAINER' 未运行"
    exit 1
fi

# 警告确认
echo ""
log_warn "即将执行数据库恢复！"
log_warn "备份文件: $BACKUP_FILE"
log_warn "数据库: $DB_NAME"
if [ "$DROP_DB" = true ]; then
    log_warn "警告: 将删除现有数据库！"
fi
echo ""
read -p "确认继续? (yes/no): " CONFIRM
if [ "$CONFIRM" != "yes" ]; then
    log_info "操作已取消"
    exit 0
fi

# 执行恢复
log_info "开始恢复数据库..."

if [ "$DROP_DB" = true ]; then
    log_info "删除现有数据库..."
    docker exec "$DB_CONTAINER" psql -U "$DB_USER" -c "DROP DATABASE IF EXISTS $DB_NAME;"
    docker exec "$DB_CONTAINER" psql -U "$DB_USER" -c "CREATE DATABASE $DB_NAME;"
    log_info "数据库已重建"
fi

# 恢复数据
if gzip -dc "$BACKUP_FILE" | docker exec -i "$DB_CONTAINER" psql -U "$DB_USER" "$DB_NAME"; then
    log_info "✓ 数据库恢复成功！"
    
    # 验证恢复
    log_info "验证恢复结果..."
    TABLE_COUNT=$(gzip -dc "$BACKUP_FILE" | grep -c "^CREATE TABLE" || echo "0")
    log_info "备份中发现的表数量: $TABLE_COUNT"
    
    ACTUAL_COUNT=$(docker exec "$DB_CONTAINER" psql -U "$DB_USER" -d "$DB_NAME" -t -c "SELECT COUNT(*) FROM information_schema.tables WHERE table_schema='public';" 2>/dev/null | tr -d '[:space:]')
    log_info "恢复后的表数量: $ACTUAL_COUNT"
    
    if [ "$TABLE_COUNT" -eq "$ACTUAL_COUNT" ] || [ "$ACTUAL_COUNT" -gt 0 ]; then
        log_info "✓ 验证通过"
        exit 0
    else
        log_warn "表数量不匹配，请手动验证数据完整性"
        exit 0
    fi
else
    log_error "数据库恢复失败"
    exit 1
fi