/* See https://github.com/ethereum/tests/wiki/Blockchain-Tests-II

   Whether a block is valid or not is a bit subtle, it's defined by presence of
   blockHeader, transactions and uncleHeaders fields. If they are missing, the block is
   invalid and we must verify that we do not accept it.

   Since some tests mix valid and invalid blocks we need to check this for every block.

   If a block is invalid it does not necessarily fail the test, if it's invalidness is
   expected we are expected to ignore it and continue processing and then validate the
   post state.
*/
func (t *BlockTest) TryBlocksInsert(chainManager *core.ChainManager) ([]btBlock, error) {
	validBlocks := make([]btBlock, 0)
	// insert the test blocks, which will execute all transactions
	for _, b := range t.Json.Blocks {
		cb, err := mustConvertBlock(b)
		if err != nil {
			if b.BlockHeader == nil {
				continue // OK - block is supposed to be invalid, continue with next block
			} else {
				return nil, fmt.Errorf("Block RLP decoding failed when expected to succeed: %v", err)
			}
		}
		// RLP decoding worked, try to insert into chain:
		_, err = chainManager.InsertChain(types.Blocks{cb})
		if err != nil {
			if b.BlockHeader == nil {
				continue // OK - block is supposed to be invalid, continue with next block
			} else {
				return nil, fmt.Errorf("Block insertion into chain failed: %v", err)
			}
		}
		if b.BlockHeader == nil {
			return nil, fmt.Errorf("Block insertion should have failed")
		}

		// validate RLP decoding by checking all values against test file JSON
		if err = validateHeader(b.BlockHeader, cb.Header()); err != nil {
			return nil, fmt.Errorf("Deserialised block header validation failed: %v", err)
		}
		validBlocks = append(validBlocks, b)
	}
	return validBlocks, nil
}

/* See https://github.com/ethereum/tests/wiki/Blockchain-Tests-II

   Whether a block is valid or not is a bit subtle, it's defined by presence of
   blockHeader, transactions and uncleHeaders fields. If they are missing, the block is
   invalid and we must verify that we do not accept it.

   Since some tests mix valid and invalid blocks we need to check this for every block.

   If a block is invalid it does not necessarily fail the test, if it's invalidness is
   expected we are expected to ignore it and continue processing and then validate the
   post state.
*/
func (t *BlockTest) TryBlocksInsert(chainManager *core.ChainManager) error {
	// insert the test blocks, which will execute all transactions
	for _, b := range t.Json.Blocks {
		cb, err := mustConvertBlock(b)
		if err != nil {
			if b.BlockHeader == nil {
				continue // OK - block is supposed to be invalid, continue with next block
			} else {
				return fmt.Errorf("Block RLP decoding failed when expected to succeed: %v", err)
			}
		}
		// RLP decoding worked, try to insert into chain:
		_, err = chainManager.InsertChain(types.Blocks{cb})
		if err != nil {
			if b.BlockHeader == nil {
				continue // OK - block is supposed to be invalid, continue with next block
			} else {
				return fmt.Errorf("Block insertion into chain failed: %v", err)
			}
		}
		if b.BlockHeader == nil {
			return fmt.Errorf("Block insertion should have failed")
		}
		err = t.validateBlockHeader(b.BlockHeader, cb.Header())
		if err != nil {
			return fmt.Errorf("Block header validation failed: %v", err)
		}
	}
	return nil
}

func hasAllBlocks(chain *core.ChainManager, bs []*types.Block) bool {
	for _, b := range bs {
		if !chain.HasBlock(b.Hash()) {
			return false
		}
	}
	return true
}

func ExportChain(chainmgr *core.ChainManager, fn string) error {
	fmt.Printf("exporting blockchain '%s'\n", fn)
	fh, err := os.OpenFile(fn, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.ModePerm)
	if err != nil {
		return err
	}
	defer fh.Close()
	if err := chainmgr.Export(fh); err != nil {
		return err
	}
	fmt.Printf("exported blockchain\n")
	return nil
}

func ExportChain(chainmgr *core.ChainManager, fn string) error {
	glog.Infoln("Exporting blockchain to", fn)
	fh, err := os.OpenFile(fn, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.ModePerm)
	if err != nil {
		return err
	}
	defer fh.Close()
	if err := chainmgr.Export(fh); err != nil {
		return err
	}
	glog.Infoln("Exported blockchain to", fn)
	return nil
}

func ExportAppendChain(chainmgr *core.ChainManager, fn string, first uint64, last uint64) error {
	glog.Infoln("Exporting blockchain to", fn)
	// TODO verify mode perms
	fh, err := os.OpenFile(fn, os.O_CREATE|os.O_APPEND|os.O_WRONLY, os.ModePerm)
	if err != nil {
		return err
	}
	defer fh.Close()
	if err := chainmgr.ExportN(fh, first, last); err != nil {
		return err
	}
	glog.Infoln("Exported blockchain to", fn)
	return nil
}

func (test *BlockTest) ValidateImportedHeaders(cm *core.ChainManager, validBlocks []btBlock) error {
	// to get constant lookup when verifying block headers by hash (some tests have many blocks)
	bmap := make(map[string]btBlock, len(test.Json.Blocks))
	for _, b := range validBlocks {
		bmap[b.BlockHeader.Hash] = b
	}

	// iterate over blocks backwards from HEAD and validate imported
	// headers vs test file. some tests have reorgs, and we import
	// block-by-block, so we can only validate imported headers after
	// all blocks have been processed by ChainManager, as they may not
	// be part of the longest chain until last block is imported.
	for b := cm.CurrentBlock(); b != nil && b.NumberU64() != 0; b = cm.GetBlock(b.Header().ParentHash) {
		bHash := common.Bytes2Hex(b.Hash().Bytes()) // hex without 0x prefix
		if err := validateHeader(bmap[bHash].BlockHeader, b.Header()); err != nil {
			return fmt.Errorf("Imported block header validation failed: %v", err)
		}
	}
	return nil
}

func ImportChain(chainmgr *core.ChainManager, fn string) error {
	fmt.Printf("importing blockchain '%s'\n", fn)
	fh, err := os.OpenFile(fn, os.O_RDONLY, os.ModePerm)
	if err != nil {
		return err
	}
	defer fh.Close()

	chainmgr.Reset()
	stream := rlp.NewStream(fh, 0)
	var i, n int

	batchSize := 2500
	blocks := make(types.Blocks, batchSize)

	for ; ; i++ {
		var b types.Block
		if err := stream.Decode(&b); err == io.EOF {
			break
		} else if err != nil {
			return fmt.Errorf("at block %d: %v", i, err)
		}

		blocks[n] = &b
		n++

		if n == batchSize {
			if _, err := chainmgr.InsertChain(blocks); err != nil {
				return fmt.Errorf("invalid block %v", err)
			}
			n = 0
			blocks = make(types.Blocks, batchSize)
		}
	}

	if n > 0 {
		if _, err := chainmgr.InsertChain(blocks[:n]); err != nil {
			return fmt.Errorf("invalid block %v", err)
		}
	}

	fmt.Printf("imported %d blocks\n", i)
	return nil
}

func ImportChain(chain *core.ChainManager, fn string) error {
	// Watch for Ctrl-C while the import is running.
	// If a signal is received, the import will stop at the next batch.
	interrupt := make(chan os.Signal, 1)
	stop := make(chan struct{})
	signal.Notify(interrupt, os.Interrupt)
	defer signal.Stop(interrupt)
	defer close(interrupt)
	go func() {
		if _, ok := <-interrupt; ok {
			glog.Info("caught interrupt during import, will stop at next batch")
		}
		close(stop)
	}()
	checkInterrupt := func() bool {
		select {
		case <-stop:
			return true
		default:
			return false
		}
	}

	glog.Infoln("Importing blockchain", fn)
	fh, err := os.Open(fn)
	if err != nil {
		return err
	}
	defer fh.Close()
	stream := rlp.NewStream(fh, 0)

	// Run actual the import.
	blocks := make(types.Blocks, importBatchSize)
	n := 0
	for batch := 0; ; batch++ {
		// Load a batch of RLP blocks.
		if checkInterrupt() {
			return fmt.Errorf("interrupted")
		}
		i := 0
		for ; i < importBatchSize; i++ {
			var b types.Block
			if err := stream.Decode(&b); err == io.EOF {
				break
			} else if err != nil {
				return fmt.Errorf("at block %d: %v", n, err)
			}
			blocks[i] = &b
			n++
		}
		if i == 0 {
			break
		}
		// Import the batch.
		if checkInterrupt() {
			return fmt.Errorf("interrupted")
		}
		if hasAllBlocks(chain, blocks[:i]) {
			glog.Infof("skipping batch %d, all blocks present [%x / %x]",
				batch, blocks[0].Hash().Bytes()[:4], blocks[i-1].Hash().Bytes()[:4])
			continue
		}
		if _, err := chain.InsertChain(blocks[:i]); err != nil {
			return fmt.Errorf("invalid block %d: %v", n, err)
		}
	}
	return nil
}