package sarama

import (
	"encoding/binary"
	"errors"
	"fmt"
	"math"

	"github.com/rcrowley/go-metrics"
)

type prepEncoder struct {
	stack  []pushEncoder
	length int
}

// primitives

func (pe *prepEncoder) putInt8(in int8) {
	pe.length++
}

func (pe *prepEncoder) putInt16(in int16) {
	pe.length += 2
}

func (pe *prepEncoder) putInt32(in int32) {
	pe.length += 4
}

func (pe *prepEncoder) putInt64(in int64) {
	pe.length += 8
}

func (pe *prepEncoder) putVarint(in int64) {
	var buf [binary.MaxVarintLen64]byte
	pe.length += binary.PutVarint(buf[:], in)
}

func (pe *prepEncoder) putUVarint(in uint64) {
	var buf [binary.MaxVarintLen64]byte
	pe.length += binary.PutUvarint(buf[:], in)
}

func (pe *prepEncoder) putArrayLength(in int) error {
	if in > math.MaxInt32 {
		return PacketEncodingError{fmt.Sprintf("array too long (%d)", in)}
	}
	pe.length += 4
	return nil
}

func (pe *prepEncoder) putCompactArrayLength(in int) {
	pe.putUVarint(uint64(in + 1))
}

func (pe *prepEncoder) putBool(in bool) {
	pe.length++
}

// arrays

func (pe *prepEncoder) putBytes(in []byte) error {
	pe.length += 4
	if in == nil {
		return nil
	}
	return pe.putRawBytes(in)
}

func (pe *prepEncoder) putVarintBytes(in []byte) error {
	if in == nil {
		pe.putVarint(-1)
		return nil
	}
	pe.putVarint(int64(len(in)))
	return pe.putRawBytes(in)
}

func (pe *prepEncoder) putCompactBytes(in []byte) error {
	pe.putUVarint(uint64(len(in) + 1))
	return pe.putRawBytes(in)
}

func (pe *prepEncoder) putCompactString(in string) error {
	pe.putCompactArrayLength(len(in))
	return pe.putRawBytes([]byte(in))
}

func (pe *prepEncoder) putNullableCompactString(in *string) error {
	if in == nil {
		pe.putUVarint(0)
		return nil
	} else {
		return pe.putCompactString(*in)
	}
}

func (pe *prepEncoder) putRawBytes(in []byte) error {
	if len(in) > math.MaxInt32 {
		return PacketEncodingError{fmt.Sprintf("byteslice too long (%d)", len(in))}
	}
	pe.length += len(in)
	return nil
}

func (pe *prepEncoder) putNullableString(in *string) error {
	if in == nil {
		pe.length += 2
		return nil
	}
	return pe.putString(*in)
}

func (pe *prepEncoder) putString(in string) error {
	pe.length += 2
	if len(in) > math.MaxInt16 {
		return PacketEncodingError{fmt.Sprintf("string too long (%d)", len(in))}
	}
	pe.length += len(in)
	return nil
}

func (pe *prepEncoder) putStringArray(in []string) error {
	err := pe.putArrayLength(len(in))
	if err != nil {
		return err
	}

	for _, str := range in {
		if err := pe.putString(str); err != nil {
			return err
		}
	}

	return nil
}

func (pe *prepEncoder) putCompactInt32Array(in []int32) error {
	if in == nil {
		return errors.New("expected int32 array to be non null")
	}

	pe.putUVarint(uint64(len(in)) + 1)
	pe.length += 4 * len(in)
	return nil
}

func (pe *prepEncoder) putNullableCompactInt32Array(in []int32) error {
	if in == nil {
		pe.putUVarint(0)
		return nil
	}

	pe.putUVarint(uint64(len(in)) + 1)
	pe.length += 4 * len(in)
	return nil
}

func (pe *prepEncoder) putInt32Array(in []int32) error {
	err := pe.putArrayLength(len(in))
	if err != nil {
		return err
	}
	pe.length += 4 * len(in)
	return nil
}

func (pe *prepEncoder) putInt64Array(in []int64) error {
	err := pe.putArrayLength(len(in))
	if err != nil {
		return err
	}
	pe.length += 8 * len(in)
	return nil
}

func (pe *prepEncoder) putEmptyTaggedFieldArray() {
	pe.putUVarint(0)
}

func (pe *prepEncoder) offset() int {
	return pe.length
}

// stackable

func (pe *prepEncoder) push(in pushEncoder) {
	in.saveOffset(pe.length)
	pe.length += in.reserveLength()
	pe.stack = append(pe.stack, in)
}

func (pe *prepEncoder) pop() error {
	in := pe.stack[len(pe.stack)-1]
	pe.stack = pe.stack[:len(pe.stack)-1]
	if dpe, ok := in.(dynamicPushEncoder); ok {
		pe.length += dpe.adjustLength(pe.length)
	}

	return nil
}

// we do not record metrics during the prep encoder pass
func (pe *prepEncoder) metricRegistry() metrics.Registry {
	return nil
}