package binlog

import (
	"b612.me/mysql/gtid"
	"b612.me/staros"
	"bytes"
	"fmt"
	"github.com/starainrt/go-mysql/replication"
	"io"
	"os"
)

type TxDetail struct {
	StartPos int
	EndPos   int
	Db       string
	Table    string
	SqlType  string
	RowCount int
}

type Transaction struct {
	GTID      string
	StartPos  int
	EndPos    int
	Size      int
	SQLOrigin string
	Timestamp int64
	RowsCount int
	Txs       []TxDetail
}

func ParseBinlogFile(path string, fx func(transaction Transaction)) error {
	return parseOneBinlog(path, fx)
}
func parseOneBinlog(path string, fx func(Transaction)) error {
	if !staros.Exists(path) {
		return os.ErrNotExist
	}
	f, err := os.Open(path)
	if f != nil {
		defer f.Close()
	}
	if err != nil {
		return err
	}

	fileTypeBytes := int64(4)

	b := make([]byte, fileTypeBytes)
	// 读取binlog头
	if _, err = f.Read(b); err != nil {
		return err
	} else if !bytes.Equal(b, replication.BinLogFileHeader) {
		//不是binlog格式
		return err
	}
	// must not seek to other position, otherwise the program may panic because formatevent, table map event is skipped
	if _, err = f.Seek(fileTypeBytes, os.SEEK_SET); err != nil {
		return err
	}
	return parseBinlogDetail(f, fx)
}

func parseBinlogDetail(r io.Reader, f func(Transaction)) error {
	parse := replication.NewBinlogParser()
	parse.SetParseTime(false)
	parse.SetUseDecimal(false)
	// process: 0, continue: 1, break: 2, EOF: 3
	var (
		err      error
		n        int64
		db       string = ""
		tb       string = ""
		sql      string = ""
		sqlType  string = ""
		rowCnt   uint32 = 0
		tbMapPos uint32 = 0
	)
	var tx Transaction
	for {
		headBuf := make([]byte, replication.EventHeaderSize)
		if _, err = io.ReadFull(r, headBuf); err == io.EOF {
			return nil
		} else if err != nil {
			return err
		}

		var h *replication.EventHeader
		h, err = parse.ParseHeader(headBuf)
		if err != nil {
			return err
		}
		//fmt.Printf("parsing %s %d %s\n", *binlog, h.LogPos, GetDatetimeStr(int64(h.Timestamp), int64(0), DATETIME_FORMAT))

		if h.EventSize <= uint32(replication.EventHeaderSize) {
			err = fmt.Errorf("invalid event header, event size is %d, too small", h.EventSize)
			return err
		}

		var buf bytes.Buffer
		if n, err = io.CopyN(&buf, r, int64(h.EventSize)-int64(replication.EventHeaderSize)); err != nil {
			err = fmt.Errorf("get event body err %v, need %d - %d, but got %d", err, h.EventSize, replication.EventHeaderSize, n)
			return err
		}

		//h.Dump(os.Stdout)

		data := buf.Bytes()
		var rawData []byte
		rawData = append(rawData, headBuf...)
		rawData = append(rawData, data...)

		eventLen := int(h.EventSize) - replication.EventHeaderSize

		if len(data) != eventLen {
			err = fmt.Errorf("invalid data size %d in event %s, less event length %d", len(data), h.EventType, eventLen)
			return err
		}

		var e replication.Event
		e, err = parse.ParseEvent(h, data, rawData)
		if err != nil {
			return err
		}
		if h.EventType == replication.TABLE_MAP_EVENT {
			tbMapPos = h.LogPos - h.EventSize // avoid mysqlbing mask the row event as unknown table row event
		}

		//e.Dump(os.Stdout)

		//binEvent := &replication.BinlogEvent{RawData: rawData, Header: h, Event: e}
		binEvent := &replication.BinlogEvent{Header: h, Event: e} // we donnot need raw data

		db, tb, sqlType, sql, rowCnt = GetDbTbAndQueryAndRowCntFromBinevent(binEvent)
		startPos := 0
		if sqlType == "query" {
			startPos = int(h.LogPos - h.EventSize)
			//fmt.Println(h.Timestamp, h.LogPos-h.EventSize, h.LogPos, db, tb, "sql="+sql, rowCnt, sqlType)
			//	cfg.StatChan <- BinEventStats{Timestamp: h.Timestamp, Binlog: *binlog, StartPos: h.LogPos - h.EventSize, StopPos: h.LogPos,
			//		Database: db, Table: tb, QuerySql: sql, RowCnt: rowCnt, QueryType: sqlType}
		} else {
			startPos = int(tbMapPos)
			//fmt.Println(h.Timestamp, tbMapPos, h.LogPos, db, tb, "sql="+sql, rowCnt, sqlType)
			//	cfg.StatChan <- BinEventStats{Timestamp: h.Timestamp, Binlog: *binlog, StartPos: tbMapPos, StopPos: h.LogPos,
			//	Database: db, Table: tb, QuerySql: sql, RowCnt: rowCnt, QueryType: sqlType}
		}
		switch sqlType {
		case "gtid":
			if tx.StartPos != 0 {
				for _, v := range tx.Txs {
					tx.RowsCount += v.RowCount
				}
				tx.Size = tx.EndPos - tx.StartPos
				if f != nil {
					f(tx)
				}
			}
			tx = Transaction{
				GTID:     sql,
				StartPos: startPos,
			}
		case "":
			tx.EndPos = int(h.LogPos)
			continue
		case "rowsquery":
			tx.EndPos = int(h.LogPos)
			tx.SQLOrigin = sql
		default:
			tx.EndPos = int(h.LogPos)
			tx.Txs = append(tx.Txs, TxDetail{
				StartPos: startPos,
				EndPos:   int(h.LogPos),
				Db:       db,
				Table:    tb,
				SqlType:  sqlType,
				RowCount: int(rowCnt),
			})
		}
	}

}

func GetDbTbAndQueryAndRowCntFromBinevent(ev *replication.BinlogEvent) (string, string, string, string, uint32) {
	var (
		db      string = ""
		tb      string = ""
		sql     string = ""
		sqlType string = ""
		rowCnt  uint32 = 0
	)

	switch ev.Header.EventType {

	case replication.WRITE_ROWS_EVENTv1,
		replication.WRITE_ROWS_EVENTv2:

		wrEvent := ev.Event.(*replication.RowsEvent)
		db = string(wrEvent.Table.Schema)
		tb = string(wrEvent.Table.Table)
		sqlType = "insert"
		rowCnt = uint32(len(wrEvent.Rows))

	case replication.UPDATE_ROWS_EVENTv1,
		replication.UPDATE_ROWS_EVENTv2:
		wrEvent := ev.Event.(*replication.RowsEvent)
		db = string(wrEvent.Table.Schema)
		tb = string(wrEvent.Table.Table)
		sqlType = "update"
		rowCnt = uint32(len(wrEvent.Rows)) / 2

	case replication.DELETE_ROWS_EVENTv1,
		replication.DELETE_ROWS_EVENTv2:

		//replication.XID_EVENT,
		//replication.TABLE_MAP_EVENT:

		wrEvent := ev.Event.(*replication.RowsEvent)
		db = string(wrEvent.Table.Schema)
		tb = string(wrEvent.Table.Table)
		sqlType = "delete"
		rowCnt = uint32(len(wrEvent.Rows))
	case replication.ROWS_QUERY_EVENT:
		queryEvent := ev.Event.(*replication.RowsQueryEvent)
		sql = string(queryEvent.Query)
		sqlType = "rowsquery"
	case replication.QUERY_EVENT:
		queryEvent := ev.Event.(*replication.QueryEvent)
		db = string(queryEvent.Schema)
		sql = string(queryEvent.Query)
		sqlType = "query"

	case replication.MARIADB_GTID_EVENT:
		// For global transaction ID, used to start a new transaction event group, instead of the old BEGIN query event, and also to mark stand-alone (ddl).
		//https://mariadb.com/kb/en/library/gtid_event/
		sql = "begin"
		sqlType = "query"

	case replication.XID_EVENT:
		// XID_EVENT represents commit。rollback transaction not in binlog
		sql = "commit"
		sqlType = "query"
	case replication.GTID_EVENT:
		ge := ev.Event.(*replication.GTIDEvent)
		gid, err := gtid.Parse(fmt.Sprintf("%s:%d", bytesToUuid(ge.SID), ge.SequenceNumber))
		if err == nil {
			sql = gid.String()
		}
		sqlType = "gtid"
	}
	return db, tb, sqlType, sql, rowCnt

}