#!/bin/bash
# ==============================================================================
# landppt 最终生产版
# 功能: 全量备份(数据+配置) | 双S3+WebDAV | 自动清理 | 启动保护
# ==============================================================================

DATA_DIR="."
DB_FILE="landppt.db"
# 关键: 备份数据库同时，也备份系统配置文件
CONFIG_FILES=".env config.json config.yaml"

SYNC_INTERVAL="${SYNC_INTERVAL:-600}"
BACKUP_KEEP="${BACKUP_KEEP:-24}"
TIMEOUT_RESTORE="120"
TIMEOUT_CMD="180"

S3_REGION="${S3_REGION:-auto}"
S3_2_REGION="${S3_2_REGION:-auto}"

log() { echo "[Backup] $(date '+%Y-%m-%d %H:%M:%S') $*"; }

run_with_timeout() {
    local t="$1"; shift
    if command -v timeout >/dev/null; then
        timeout "$t" "$@"
        return $?
    else
        "$@"
    fi
}

# ----------------- 基础工具函数 -----------------
has_webdav() { [[ -n "$WEBDAV_URL" && -n "$WEBDAV_USERNAME" && -n "$WEBDAV_PASSWORD" ]]; }
has_s3()     { [[ -n "$S3_ENDPOINT_URL" && -n "$S3_BUCKET" && -n "$S3_ACCESS_KEY_ID" ]]; }
has_s3_2()   { [[ -n "$S3_2_ENDPOINT_URL" && -n "$S3_2_BUCKET" && -n "$S3_2_ACCESS_KEY_ID" ]]; }

get_webdav_url() {
    local file="$1"
    local base="${WEBDAV_URL%/}"
    local sub="${WEBDAV_BACKUP_PATH#/}"
    sub="${sub%/}"
    [ -n "$sub" ] && echo "$base/$sub/$file" || echo "$base/$file"
}

get_webdav_latest_name() {
    local url=$(get_webdav_url "")
    run_with_timeout 30 curl -s -X PROPFIND -H "Depth: 1" \
        -u "$WEBDAV_USERNAME:$WEBDAV_PASSWORD" \
        --connect-timeout 15 "$url" \
        | grep -o 'landppt_backup_[0-9_]*\.tar\.gz' \
        | sort -u | sort | tail -n 1
}

download_webdav_file() {
    local file="$1"
    local dl_path="$2"
    log "从 WebDAV 下载: $file ..."
    run_with_timeout "$TIMEOUT_RESTORE" curl -s -f -L \
        -u "$WEBDAV_USERNAME:$WEBDAV_PASSWORD" \
        --connect-timeout 15 \
        -o "$dl_path" "$(get_webdav_url "$file")"
}

get_s3_latest_name() {
    local ENDPOINT="$1" BUCKET="$2" ACCESS="$3" SECRET="$4" REGION="$5"
    export AWS_ACCESS_KEY_ID="$ACCESS"
    export AWS_SECRET_ACCESS_KEY="$SECRET"
    export AWS_DEFAULT_REGION="$REGION"
    run_with_timeout 30 aws --endpoint-url "$ENDPOINT" --region "$REGION" s3 ls "s3://$BUCKET/" 2>/dev/null \
        | awk '{print $4}' | grep 'landppt_backup_.*\.tar\.gz$' | sort | tail -n 1
}

download_s3_file() {
    local ENDPOINT="$1" BUCKET="$2" ACCESS="$3" SECRET="$4" REGION="$5" FILE="$6" DL_PATH="$7"
    log "从 S3 下载: $FILE (Region: $REGION)..."
    export AWS_ACCESS_KEY_ID="$ACCESS"
    export AWS_SECRET_ACCESS_KEY="$SECRET"
    export AWS_DEFAULT_REGION="$REGION"
    rm -f "$DL_PATH"
    if run_with_timeout "$TIMEOUT_RESTORE" aws --endpoint-url "$ENDPOINT" --region "$REGION" s3 cp "s3://$BUCKET/$FILE" "$DL_PATH" --quiet; then
        [ -s "$DL_PATH" ] && return 0
    fi
    return 1
}

# ----------------- 解压/打包 核心逻辑 -----------------

extract_data() {
    local tar_path="$1"
    mkdir -p "$DATA_DIR"
    
    # 解压所有内容 (数据库 + .env配置)
    if tar -xzf "$tar_path" -C "$DATA_DIR" 2>/dev/null; then
        
        # 验证数据库完整性
        if ls "$DATA_DIR"/landppt.db* 1> /dev/null 2>&1; then
            return 0
        fi
        
        # 兼容性修复：如果文件不在根目录，尝试查找并归位
        local found=$(find "$DATA_DIR" -name "landppt.db" -type f | head -n 1)
        if [ -n "$found" ] && [ "$found" != "$DATA_DIR/$DB_FILE" ]; then
            mv "$found" "$DATA_DIR/$DB_FILE"
            [ -f "${found}-shm" ] && mv "${found}-shm" "$DATA_DIR/${DB_FILE}-shm"
            [ -f "${found}-wal" ] && mv "${found}-wal" "$DATA_DIR/${DB_FILE}-wal"
            return 0
        fi
    fi
    return 1
}

# ==============================================================================
# 阶段 1: 恢复流程 (阻塞应用启动)
# ==============================================================================

log ">>> 启动初始化..."

# 只要本地有数据库，跳过恢复 (保护现有数据)
if [ -f "$DATA_DIR/$DB_FILE" ] && [ -s "$DATA_DIR/$DB_FILE" ]; then
    log "本地数据已存在，跳过恢复。"
else
    CANDIDATES_FILE="/tmp/backup_candidates.txt"
    > "$CANDIDATES_FILE"

    if has_s3; then
        F=$(get_s3_latest_name "$S3_ENDPOINT_URL" "$S3_BUCKET" "$S3_ACCESS_KEY_ID" "$S3_SECRET_ACCESS_KEY" "$S3_REGION")
        [ -n "$F" ] && echo "$F S3_MAIN" >> "$CANDIDATES_FILE" && log "发现 S3(主): $F"
    fi
    if has_s3_2; then
        F=$(get_s3_latest_name "$S3_2_ENDPOINT_URL" "$S3_2_BUCKET" "$S3_2_ACCESS_KEY_ID" "$S3_2_SECRET_ACCESS_KEY" "$S3_2_REGION")
        [ -n "$F" ] && echo "$F S3_SEC" >> "$CANDIDATES_FILE" && log "发现 S3(备): $F"
    fi
    if has_webdav; then
        F=$(get_webdav_latest_name)
        [ -n "$F" ] && echo "$F WEBDAV" >> "$CANDIDATES_FILE" && log "发现 WebDAV: $F"
    fi

    BEST_LINE=$(sort -r "$CANDIDATES_FILE" | head -n 1)
    
    if [ -n "$BEST_LINE" ]; then
        TARGET_FILE=$(echo "$BEST_LINE" | awk '{print $1}')
        SOURCE_TYPE=$(echo "$BEST_LINE" | awk '{print $2}')
        DL_FILE="/tmp/restore.tar.gz"
        
        log ">>> 正在恢复: $TARGET_FILE (来源: $SOURCE_TYPE)"
        SUCCESS=0
        
        case "$SOURCE_TYPE" in
            "S3_MAIN") download_s3_file "$S3_ENDPOINT_URL" "$S3_BUCKET" "$S3_ACCESS_KEY_ID" "$S3_SECRET_ACCESS_KEY" "$S3_REGION" "$TARGET_FILE" "$DL_FILE" && SUCCESS=1 ;;
            "S3_SEC")  download_s3_file "$S3_2_ENDPOINT_URL" "$S3_2_BUCKET" "$S3_2_ACCESS_KEY_ID" "$S3_2_SECRET_ACCESS_KEY" "$S3_2_REGION" "$TARGET_FILE" "$DL_FILE" && SUCCESS=1 ;;
            "WEBDAV")  download_webdav_file "$TARGET_FILE" "$DL_FILE" && SUCCESS=1 ;;
        esac
        
        if [ $SUCCESS -eq 1 ] && extract_data "$DL_FILE"; then
            log "✅ 恢复成功！(数据与配置已就绪)"
        else
            log "❌ 恢复失败"
        fi
        rm -f "$DL_FILE"
    else
        log "未找到备份，启动全新实例。"
    fi
    rm -f "$CANDIDATES_FILE"
fi

log ">>> 初始化结束，应用正在启动..."

# ==============================================================================
# 阶段 2: 后台备份循环
# ==============================================================================
(
    sleep 60
    while true; do
        if [ -f "$DATA_DIR/$DB_FILE" ]; then
            TS=$(date +%Y%m%d_%H%M%S)
            BACKUP_NAME="landppt_backup_${TS}.tar.gz"
            TMP_BAK="/tmp/$BACKUP_NAME"
            
            # --- 打包逻辑 (同时备份DB和配置) ---
            (
                cd "$DATA_DIR"
                FILES_TO_BACKUP="landppt.db*"
                for cf in $CONFIG_FILES; do
                    if [ -f "$cf" ]; then
                        FILES_TO_BACKUP="$FILES_TO_BACKUP $cf"
                    fi
                done
                tar -czf "$TMP_BAK" $FILES_TO_BACKUP >/dev/null 2>&1 || [ $? -eq 1 ]
            )
            
            # --- 1. WebDAV 备份 ---
            if has_webdav; then
                UPLOAD_URL=$(get_webdav_url "$BACKUP_NAME")
                if run_with_timeout "$TIMEOUT_CMD" curl -s -f --connect-timeout 15 \
                    -u "$WEBDAV_USERNAME:$WEBDAV_PASSWORD" \
                    -T "$TMP_BAK" "$UPLOAD_URL" >/dev/null 2>&1; then
                    
                    # WebDAV 清理
                    LIST_URL=$(get_webdav_url "")
                    ALL_FILES=$(curl -s -X PROPFIND -H "Depth: 1" -u "$WEBDAV_USERNAME:$WEBDAV_PASSWORD" --connect-timeout 15 "$LIST_URL" \
                        | grep -o 'landppt_backup_[0-9_]*\.tar\.gz' | sort -u | sort)
                    COUNT=$(echo "$ALL_FILES" | grep -c .)
                    if [ "$COUNT" -gt "$BACKUP_KEEP" ]; then
                        DEL_COUNT=$(($COUNT - $BACKUP_KEEP))
                        echo "$ALL_FILES" | head -n "$DEL_COUNT" | while read -r F; do
                            [ -n "$F" ] && curl -s -X DELETE -u "$WEBDAV_USERNAME:$WEBDAV_PASSWORD" "$(get_webdav_url "$F")" >/dev/null 2>&1
                        done
                    fi
                fi
            fi
            
            # --- 2. S3 (主) 备份 ---
            if has_s3; then
                export AWS_ACCESS_KEY_ID="$S3_ACCESS_KEY_ID"
                export AWS_SECRET_ACCESS_KEY="$S3_SECRET_ACCESS_KEY"
                export AWS_DEFAULT_REGION="$S3_REGION"
                
                if run_with_timeout "$TIMEOUT_CMD" aws --endpoint-url "$S3_ENDPOINT_URL" --region "$S3_REGION" s3 cp "$TMP_BAK" "s3://$S3_BUCKET/$BACKUP_NAME" --quiet >/dev/null 2>&1; then
                    # S3 清理
                    FILES=$(aws --endpoint-url "$S3_ENDPOINT_URL" --region "$S3_REGION" s3 ls "s3://$S3_BUCKET/" 2>/dev/null | awk '{print $4}' | grep 'landppt_backup_' | sort)
                    COUNT=$(echo "$FILES" | grep -c .)
                    if [ "$COUNT" -gt "$BACKUP_KEEP" ]; then
                        DEL=$(($COUNT - $BACKUP_KEEP))
                        echo "$FILES" | head -n "$DEL" | while read -r F; do
                            [ -n "$F" ] && aws --endpoint-url "$S3_ENDPOINT_URL" --region "$S3_REGION" s3 rm "s3://$S3_BUCKET/$F" --quiet
                        done
                    fi
                fi
            fi

            # --- 3. S3 (备) 备份 ---
            if has_s3_2; then
                export AWS_ACCESS_KEY_ID="$S3_2_ACCESS_KEY_ID"
                export AWS_SECRET_ACCESS_KEY="$S3_2_SECRET_ACCESS_KEY"
                export AWS_DEFAULT_REGION="$S3_2_REGION"
                
                if run_with_timeout "$TIMEOUT_CMD" aws --endpoint-url "$S3_2_ENDPOINT_URL" --region "$S3_2_REGION" s3 cp "$TMP_BAK" "s3://$S3_2_BUCKET/$BACKUP_NAME" --quiet >/dev/null 2>&1; then
                    # S3 (备) 清理
                    FILES=$(aws --endpoint-url "$S3_2_ENDPOINT_URL" --region "$S3_2_REGION" s3 ls "s3://$S3_2_BUCKET/" 2>/dev/null | awk '{print $4}' | grep 'landppt_backup_' | sort)
                    COUNT=$(echo "$FILES" | grep -c .)
                    if [ "$COUNT" -gt "$BACKUP_KEEP" ]; then
                        DEL=$(($COUNT - $BACKUP_KEEP))
                        echo "$FILES" | head -n "$DEL" | while read -r F; do
                            [ -n "$F" ] && aws --endpoint-url "$S3_2_ENDPOINT_URL" --region "$S3_2_REGION" s3 rm "s3://$S3_2_BUCKET/$F" --quiet
                        done
                    fi
                fi
            fi
            
            rm -f "$TMP_BAK"
            log "备份完成: $BACKUP_NAME"
        fi
        sleep "$SYNC_INTERVAL"
    done
) &

exit 0