package mysqlserver

import (
	"mysql-tunnel/internal/navicat"
)

func encodeColumnCount(n int) []byte {
	return appendLenencInt(nil, uint64(n))
}

func encodeColumn(f navicat.Field) []byte {
	typ := byte(f.Type)
	charset := uint16(charsetUTF8MB4)
	if isNumericType(typ) || f.Flags&uint32(flagBinary) != 0 && isBlobType(typ) {
		charset = uint16(charsetBinary)
	}
	if isNumericType(typ) {
		charset = uint16(charsetBinary)
	}
	length := f.Length
	if length == 0 {
		length = uint32(len(f.Name))
		if length == 0 {
			length = 64
		}
	}
	flags := uint16(f.Flags)
	decimals := byte(0)
	if typ == typeFloat || typ == typeDouble || typ == typeNewDecimal || typ == typeDecimal {
		decimals = 31
	}

	b := appendLenencString(nil, []byte("def"))
	b = appendLenencString(b, nil) // schema
	b = appendLenencString(b, []byte(f.Table))
	b = appendLenencString(b, []byte(f.Table))
	b = appendLenencString(b, []byte(f.Name))
	b = appendLenencString(b, []byte(f.Name))
	b = appendLenencInt(b, 0x0c)
	b = appendU16(b, charset)
	b = appendU32(b, length)
	b = append(b, typ)
	b = appendU16(b, flags)
	b = append(b, decimals, 0x00, 0x00)
	return b
}

func encodeTextRow(row []navicat.Cell) []byte {
	var b []byte
	for _, c := range row {
		if c.Null {
			b = append(b, markerNull)
			continue
		}
		b = appendLenencString(b, c.Bytes)
	}
	return b
}

func isBlobType(t byte) bool {
	switch t {
	case typeTinyBlob, typeMediumBlob, typeLongBlob, typeBlob:
		return true
	}
	return false
}

func (p *packetConn) writeResultSet(res navicat.Result, caps uint32, status uint16) error {
	if err := p.writePacket(encodeColumnCount(len(res.Fields))); err != nil {
		return err
	}
	for _, f := range res.Fields {
		if err := p.writePacket(encodeColumn(f)); err != nil {
			return err
		}
	}
	if caps&clientDeprecateEOF != 0 {
		if err := p.writeOK(0, 0, status, 0); err != nil {
			return err
		}
	} else {
		if err := p.writePacket(encodeEOF(0, status)); err != nil {
			return err
		}
	}
	for _, row := range res.Rows {
		if err := p.writePacket(encodeTextRow(row)); err != nil {
			return err
		}
	}
	if caps&clientDeprecateEOF != 0 {
		return p.writeOK(uint64(res.AffectedRows), uint64(res.InsertID), status, 0)
	}
	return p.writePacket(encodeEOF(0, status))
}