package pgproto3

import (
	"bytes"
	"encoding/binary"
	"encoding/hex"
	"encoding/json"
)

type Bind struct {
	DestinationPortal    string
	PreparedStatement    string
	ParameterFormatCodes []int16
	Parameters           [][]byte
	ResultFormatCodes    []int16
}

func (*Bind) Frontend() {}

func (dst *Bind) Decode(src []byte) error {
	*dst = Bind{}

	idx := bytes.IndexByte(src, 0)
	if idx < 0 {
		return &invalidMessageFormatErr{messageType: "Bind"}
	}
	dst.DestinationPortal = string(src[:idx])
	rp := idx + 1

	idx = bytes.IndexByte(src[rp:], 0)
	if idx < 0 {
		return &invalidMessageFormatErr{messageType: "Bind"}
	}
	dst.PreparedStatement = string(src[rp : rp+idx])
	rp += idx + 1

	if len(src[rp:]) < 2 {
		return &invalidMessageFormatErr{messageType: "Bind"}
	}
	parameterFormatCodeCount := int(binary.BigEndian.Uint16(src[rp:]))
	rp += 2

	if parameterFormatCodeCount > 0 {
		dst.ParameterFormatCodes = make([]int16, parameterFormatCodeCount)

		if len(src[rp:]) < len(dst.ParameterFormatCodes)*2 {
			return &invalidMessageFormatErr{messageType: "Bind"}
		}
		for i := 0; i < parameterFormatCodeCount; i++ {
			dst.ParameterFormatCodes[i] = int16(binary.BigEndian.Uint16(src[rp:]))
			rp += 2
		}
	}

	if len(src[rp:]) < 2 {
		return &invalidMessageFormatErr{messageType: "Bind"}
	}
	parameterCount := int(binary.BigEndian.Uint16(src[rp:]))
	rp += 2

	if parameterCount > 0 {
		dst.Parameters = make([][]byte, parameterCount)

		for i := 0; i < parameterCount; i++ {
			if len(src[rp:]) < 4 {
				return &invalidMessageFormatErr{messageType: "Bind"}
			}

			msgSize := int(int32(binary.BigEndian.Uint32(src[rp:])))
			rp += 4

			// null
			if msgSize == -1 {
				continue
			}

			if len(src[rp:]) < msgSize {
				return &invalidMessageFormatErr{messageType: "Bind"}
			}

			dst.Parameters[i] = src[rp : rp+msgSize]
			rp += msgSize
		}
	}

	if len(src[rp:]) < 2 {
		return &invalidMessageFormatErr{messageType: "Bind"}
	}
	resultFormatCodeCount := int(binary.BigEndian.Uint16(src[rp:]))
	rp += 2

	dst.ResultFormatCodes = make([]int16, resultFormatCodeCount)
	if len(src[rp:]) < len(dst.ResultFormatCodes)*2 {
		return &invalidMessageFormatErr{messageType: "Bind"}
	}
	for i := 0; i < resultFormatCodeCount; i++ {
		dst.ResultFormatCodes[i] = int16(binary.BigEndian.Uint16(src[rp:]))
		rp += 2
	}

	return nil
}

func (src *Bind) MarshalBinary() ([]byte, error) {
	var bigEndian BigEndianBuf
	buf := &bytes.Buffer{}

	buf.WriteByte('B')
	buf.Write(bigEndian.Uint32(0))

	buf.WriteString(src.DestinationPortal)
	buf.WriteByte(0)
	buf.WriteString(src.PreparedStatement)
	buf.WriteByte(0)

	buf.Write(bigEndian.Uint16(uint16(len(src.ParameterFormatCodes))))

	for _, fc := range src.ParameterFormatCodes {
		buf.Write(bigEndian.Int16(fc))
	}

	buf.Write(bigEndian.Uint16(uint16(len(src.Parameters))))

	for _, p := range src.Parameters {
		if p == nil {
			buf.Write(bigEndian.Int32(-1))
			continue
		}

		buf.Write(bigEndian.Int32(int32(len(p))))
		buf.Write(p)
	}

	buf.Write(bigEndian.Uint16(uint16(len(src.ResultFormatCodes))))

	for _, fc := range src.ResultFormatCodes {
		buf.Write(bigEndian.Int16(fc))
	}

	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))

	return buf.Bytes(), nil
}

func (src *Bind) MarshalJSON() ([]byte, error) {
	formattedParameters := make([]map[string]string, len(src.Parameters))
	for i, p := range src.Parameters {
		if p == nil {
			continue
		}

		if src.ParameterFormatCodes[i] == 0 {
			formattedParameters[i] = map[string]string{"text": string(p)}
		} else {
			formattedParameters[i] = map[string]string{"binary": hex.EncodeToString(p)}
		}
	}

	return json.Marshal(struct {
		Type                 string
		DestinationPortal    string
		PreparedStatement    string
		ParameterFormatCodes []int16
		Parameters           []map[string]string
		ResultFormatCodes    []int16
	}{
		Type:                 "Bind",
		DestinationPortal:    src.DestinationPortal,
		PreparedStatement:    src.PreparedStatement,
		ParameterFormatCodes: src.ParameterFormatCodes,
		Parameters:           formattedParameters,
		ResultFormatCodes:    src.ResultFormatCodes,
	})
}