from flask import Flask
import json

mine = Flask(__name__)
db = mariadb.connect(**config)

@app.get('/')
def mine():
    # TODO: return a page to mine through the browser
    return 200

###
# Submit a block to the chain.
# This method calls the Block().validate() method to validate the block schema.
# This method performs additional validations against the rest of the chain.
###
@app.post('/blocks')
def blocks_post():
    previousBlock = get_last_block()
    try:
        newBlock = Block(data=request.get_json())
        newBlock.validate()
        previousBlock = db.get_last_block()
        if newBlock.previousHash != previousBlock.blockHash:
            raise Block.Invalid(
                f"Incorrect previous hash - should be {previousBlock.blockHash}."
                )
        if newBlock.timestamp <= previousBlock.timestamp:
            raise Block.Invalid(
                "Timestamp is later than previous block."
                )
        if newBlock.height != previousBlock.height + 1:
            raise Block.Invalid(
                f"Incorrect block height - should be {previousBlock.height + 1}."
                )
        if newBlock.difficulty != DIFFICULTY_REQUIREMENT:
            raise Block.Invalid(
                f"Incorrect difficulty - should be {DIFFICULTY_REQUIREMENT}."
                )
        if len(newBlock.transactions) == 0:
            raise Block.Invalid(
                "Block contains no transactions."
                )
        for transaction in newBlock.transactions:
            pendingTransaction = db.get_transaction(transaction.transactionId)
            if not pendingTransaction:
                raise Transaction.Invalid(
                    f"No matching pending transaction for {transaction.transactionId}."
                    )
            if not pendingTransaction.pending:
                raise Transaction.AlreadyFulfilled(
                    f"Transaction {transaction.transactionId} has already been fulfilled."
                    )
            if transaction.timestamp != pendingTransaction.timestamp:
                raise Transaction.Invalid(
                    f"Incorrect timestamp on {transaction.transactionId}."
                    )
            if transaction.cardId != pendingTransaction.cardId:
                raise Transaction.Invalid(
                    f"Incorrect cardId on {transaction.transactionId}."
                    )
            if transaction.sender != pendingTransaction.sender:
                raise Transaction.Invalid(
                    f"Incorrect sender on {transaction.transactionId}."
                    )
            if transaction.recipient != pendingTransaction.recipient:
                raise Transaction.Invalid(
                    f"Incorrect recipient on {transaction.transactionId}."
                    )
            if transaction.signature != pendingTransaction.signature:
                raise Transaction.Invalid(
                    f"Incorrect signature on {transaction.transactionId}."
                    )
        # TODO: write to database
        with open(f"{DATA_PATH}/{newBlock.blockId}.json", 'w') as f:
            f.write(str(newBlock))
        # TODO: update peers
        return str(newBlock), 200
    except: Transaction.Invalid as e:
        return e, e.statusCode
    except: Transaction.AlreadyFulfilled as e:
        return e, e.statusCode
    except: Card.Invalid as e:
        return e, e.statusCode
    except: Block.Invalid as e:
        return e, e.statusCode

###
# Retrieve blocks and block data.
# Returns a skeleton block to be mined by default.
# Queries for a specific block when given parameters.
###
@app.get('/blocks')
def blocks_get():
    blockHash = request.args.get('blockHash', None)
    height = request.args.get('height', None)
    # TODO: block queries
    return str(
        Block(
            previousHash = lastBlock.blockHash,
            height = lastBlock.height + 1,
            difficulty = DIFFICULTY_REQUIREMENT,
            transactions = [
                Transaction(data=each) for each in get_pending_transactions()
                ]
            )
        )

###
# Retrieve card data
###
@app.get('/cards')
def cards_get():
    # TODO: query cards
    return 200

###
# Submit a transaction to be mined in a block.
# This method performs a number of validations on the submitted transaction and returns
# a status code result.
###
@app.put('/transactions')
def transactions_put():
    try:
        newTransaction = Transaction(data=request.get_json())
        newTransaction.validate()
        # TODO: validate transaction against blockchain
        # TODO: add transaction to database
        # TODO: update peers?
        return 200
    except Transaction.Unauthorized as e:
        return e, e.statusCode
    except Transaction.Invalid as e:
        return e, e.statusCode

###
# Retrieve a transaction.
###
@app.get('/transactions')
def transactions_get():
    transactionId = request.args.get('transactionId', None)
    return get_transaction_by_id(transactionId) if transactionId else json.dumps(
        db.get_pending_transactions()
        )

@app.post('/peers')
def peers_post():
    # TODO: validate peer
    # TODO: add peers to database
    return 200

@app.get('/peers')
def peers_get():
    # TODO: query peers
    return 200

if __name__ == "__main__":
    app.run()