#!/bin/bash

# Memory 数据库备份脚本
# 功能：备份 SQLite 数据库到 R2，保留最近 7 天的备份

set -e

# ============ 配置区域 ============
# R2 配置
R2_ACCOUNT_ID="ebf33b5ee4eb26f32af0c6e06102e000"
R2_ACCESS_KEY_ID="8acbc8a9386d60d0e8dac6bd8165c618"
R2_ACCESS_KEY_SECRET="72935e23b5b4be8fda99008e75285e8ac778f8926656c42780b25785bb149443"
R2_BUCKET_NAME="memory"
R2_BACKUP_PATH="memory-backup"

# 数据库路径
DB_PATH="/amos/memory/data/memory.db"

# 备份保留天数
KEEP_DAYS=7

# 日志文件
LOG_FILE="/var/log/memory-backup.log"

# ============ 函数定义 ============

log() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" | tee -a "$LOG_FILE"
}

# 上传备份到 R2
upload_backup() {
    local backup_file=$1
    local remote_name=$2
    
    AWS_ACCESS_KEY_ID=$R2_ACCESS_KEY_ID \
    AWS_SECRET_ACCESS_KEY=$R2_ACCESS_KEY_SECRET \
    aws s3 cp "$backup_file" "s3://${R2_BUCKET_NAME}/${R2_BACKUP_PATH}/${remote_name}" \
        --endpoint-url "https://${R2_ACCOUNT_ID}.r2.cloudflarestorage.com"
}

# 清理旧备份，只保留最近 N 天
cleanup_old_backups() {
    log "清理旧备份..."
    
    # 列出所有备份文件，按时间倒序排列
    local backup_list=$(AWS_ACCESS_KEY_ID=$R2_ACCESS_KEY_ID \
        AWS_SECRET_ACCESS_KEY=$R2_ACCESS_KEY_SECRET \
        aws s3 ls "s3://${R2_BUCKET_NAME}/${R2_BACKUP_PATH}/" \
        --endpoint-url "https://${R2_ACCOUNT_ID}.r2.cloudflarestorage.com" \
        | grep "memory-.*\.db" \
        | sort -r \
        | awk '{print $4}')
    
    # 跳过前 N 个（最新的），删除其余的
    local count=0
    for backup in $backup_list; do
        count=$((count + 1))
        if [ $count -gt $KEEP_DAYS ]; then
            log "   删除: $backup"
            AWS_ACCESS_KEY_ID=$R2_ACCESS_KEY_ID \
            AWS_SECRET_ACCESS_KEY=$R2_ACCESS_KEY_SECRET \
            aws s3 rm "s3://${R2_BUCKET_NAME}/${R2_BACKUP_PATH}/${backup}" \
                --endpoint-url "https://${R2_ACCOUNT_ID}.r2.cloudflarestorage.com"
        fi
    done
    
    if [ $count -le $KEEP_DAYS ]; then
        log "   无需清理，当前共 ${count} 个备份"
    else
        log "   已清理 $((count - KEEP_DAYS)) 个旧备份"
    fi
}

# ============ 主流程 ============

log "========== 开始备份 =========="

# 检查数据库文件是否存在
if [ ! -f "$DB_PATH" ]; then
    log "❌ 数据库文件不存在: $DB_PATH"
    exit 1
fi

# 生成备份文件名（带日期）
DATE=$(date '+%Y-%m-%d')
BACKUP_NAME="memory-${DATE}.db"
TEMP_BACKUP="/tmp/${BACKUP_NAME}"

# 使用 sqlite3 的 .backup 命令进行热备份（避免数据损坏）
log "备份数据库..."
sqlite3 "$DB_PATH" ".backup '$TEMP_BACKUP'"

# 上传到 R2
log "上传到 R2..."
upload_backup "$TEMP_BACKUP" "$BACKUP_NAME"

# 清理临时文件
rm -f "$TEMP_BACKUP"

# 清理旧备份
cleanup_old_backups

log "✅ 备份完成: ${BACKUP_NAME}"
log "========== 备份结束 =========="