package types

import (
	"bytes"

	"github.com/pkg/errors"
)

// BlockMeta contains meta information.
type BlockMeta struct {
	BlockID   BlockID `json:"block_id"`
	BlockSize int     `json:"block_size"`
	Header    Header  `json:"header"`
	NumTxs    int     `json:"num_txs"`
}

// NewBlockMeta returns a new BlockMeta.
func NewBlockMeta(block *Block, blockParts *PartSet) *BlockMeta {
	return &BlockMeta{
		BlockID:   BlockID{block.Hash(), blockParts.Header()},
		BlockSize: block.Size(),
		Header:    block.Header,
		NumTxs:    len(block.Data.Txs),
	}
}

//-----------------------------------------------------------
// These methods are for Protobuf Compatibility

// Size returns the size of the amino encoding, in bytes.
func (bm *BlockMeta) Size() int {
	bs, _ := bm.Marshal()
	return len(bs)
}

// Marshal returns the amino encoding.
func (bm *BlockMeta) Marshal() ([]byte, error) {
	return cdc.MarshalBinaryBare(bm)
}

// MarshalTo calls Marshal and copies to the given buffer.
func (bm *BlockMeta) MarshalTo(data []byte) (int, error) {
	bs, err := bm.Marshal()
	if err != nil {
		return -1, err
	}
	return copy(data, bs), nil
}

// Unmarshal deserializes from amino encoded form.
func (bm *BlockMeta) Unmarshal(bs []byte) error {
	return cdc.UnmarshalBinaryBare(bs, bm)
}

// ValidateBasic performs basic validation.
func (bm *BlockMeta) ValidateBasic() error {
	if err := bm.BlockID.ValidateBasic(); err != nil {
		return err
	}
	if !bytes.Equal(bm.BlockID.Hash, bm.Header.Hash()) {
		return errors.Errorf("expected BlockID#Hash and Header#Hash to be the same, got %X != %X",
			bm.BlockID.Hash, bm.Header.Hash())
	}
	return nil
}