package metrics

import (
	"encoding/json"
	"github.com/TeaOSLab/EdgeCommon/pkg/serverconfigs"
	"github.com/TeaOSLab/EdgeNode/internal/remotelogs"
	"github.com/TeaOSLab/EdgeNode/internal/utils/dbs"
	"github.com/iwind/TeaGo/Tea"
	"github.com/iwind/TeaGo/types"
	"os"
)

func MigrateSQLiteTaskToKV(item *serverconfigs.MetricItemConfig) error {
	var itemIdString = types.String(item.Id)
	var sqlitePath = Tea.Root + "/data/metric." + itemIdString + ".db"
	_, err := os.Stat(sqlitePath)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}

	dst := NewKVTask(item)
	err = dst.Init()
	if err != nil {
		return err
	}

	err = dst.Truncate()
	if err != nil {
		return err
	}

	remotelogs.Println("METRIC", "migrating sqlite task '"+itemIdString+"' to kvstore ...")

	src := NewSQLiteTask(item)
	err = src.Init()
	if err != nil {
		return err
	}
	defer closeSQLiteTask(src)

	var offset = 0
	const size = 1000
	for {
		rows, queryErr := src.db.Query(`SELECT "hash", "keys", "value", "time", "serverId" FROM "`+src.statTableName+`" WHERE "version"=? ORDER BY "id" ASC LIMIT ?, ?`, item.Version, offset, size)
		if queryErr != nil {
			return queryErr
		}

		var countRows int
		for rows.Next() {
			countRows++

			var hash string
			var keysData []byte
			var value float64
			var timeString string
			var serverId int64

			scanErr := rows.Scan(&hash, &keysData, &value, &timeString, &serverId)
			if scanErr != nil {
				_ = rows.Close()
				return scanErr
			}

			var keys []string
			if len(keysData) > 0 {
				unmarshalErr := json.Unmarshal(keysData, &keys)
				if unmarshalErr != nil {
					_ = rows.Close()
					return unmarshalErr
				}
			}

			insertErr := dst.InsertStat(&Stat{
				ServerId: serverId,
				Keys:     keys,
				Hash:     hash,
				Value:    int64(value),
				Time:     timeString,
			})
			if insertErr != nil {
				_ = rows.Close()
				return insertErr
			}
		}

		err = rows.Err()
		if err != nil {
			_ = rows.Close()
			return err
		}

		closeErr := rows.Close()
		if closeErr != nil {
			return closeErr
		}

		if countRows < size {
			break
		}
		offset += size
	}

	err = dst.Flush()
	if err != nil {
		return err
	}

	err = removeMetricSQLiteFiles(sqlitePath)
	if err != nil {
		return err
	}

	remotelogs.Println("METRIC", "migrated sqlite task '"+itemIdString+"' to kvstore")
	return nil
}

func closeSQLiteTask(task *SQLiteTask) {
	if task == nil {
		return
	}

	for _, stmt := range []*dbs.Stmt{
		task.insertStatStmt,
		task.deleteByVersionStmt,
		task.deleteByExpiresTimeStmt,
		task.selectTopStmt,
		task.sumStmt,
	} {
		if stmt != nil {
			_ = stmt.Close()
		}
	}

	if task.db != nil {
		_ = task.db.Close()
	}
}

func removeMetricSQLiteFiles(path string) error {
	for _, filename := range []string{path, path + "-shm", path + "-wal"} {
		err := os.Remove(filename)
		if err != nil && !os.IsNotExist(err) {
			return err
		}
	}
	return nil
}