# Interacting with the Dexter's blockchain with multiple nodes using HTTP requests

from flask import Flask, jsonify, request

from blockChain import Blockchain

# Initialise our node with identifier and instantiate the Blockchain class
app = Flask(__name__)
blockchain = Blockchain()


# API endpoint to mine a block, it is an HTTP GET request
@app.route('/mine', methods=['GET'])
# Method to mine a block
def mine():
    # To ensure that only delegates elected by voting can mine a new block
    current_port = "localhost:" + str(port)
    if current_port in blockchain.delegates:
        
        # To ensure that a new block is mined only if there are atleast 2 transactions
        if len(blockchain.unverified_transactions) >= 2:
            last_block = blockchain.last_block
            previous_hash = blockchain.hash(last_block)
            block = blockchain.new_block(previous_hash)
            
            response = {
                'message': "New block mined!",
                'index': block['index'],
                'transactions': block['transactions'],
                'previous_hash': block['previous_hash']
            }
            print(len(blockchain.unverified_transactions))
            return jsonify(response), 200
        
        else:
            response = {
                'message': 'Not enough transactions to mine a new block and add to chain!'
            }
            print(len(blockchain.unverified_transactions))
            return jsonify(response), 400
    else:
        response = {
            'message': 'You are not authorised to mine block! Only delegates can mine.'
        }
        return jsonify(response), 400


# Endpoint for a new transaction
@app.route('/transactions/new', methods=['POST'])
def new_transaction():
    values = request.get_json()
    
    required = ['Customer name', 'Item name', 'Total billing amount']
    if not all(k in values for k in required):
        return 'Missing values! Please enter customer name, item name and billing amount.', 400
    
    index = blockchain.new_transaction(values['Customer name'], values['Item name'], values['Total billing amount'])
    
    response = {
        'message': f'Transaction will be added to block {index}'
    }
    return jsonify(response), 201


# Endpoint for viewing the blockchain
@app.route('/chain', methods=['GET'])
def full_chain():
    response = {
        'chain': blockchain.chain,
        'length': len(blockchain.chain)
    }
    return jsonify(response), 200


# Endpoint for adding HTTP address of new nodes along with their stakes in the network.
@app.route('/nodes/add', methods=['POST'])
def add_nodes():
    values = request.get_json()
    required = ['nodes', 'stake']
    
    if not all(k in values for k in required):
        return 'Error', 400
    
    blockchain.add_node(values['nodes'], values['stake'])
    
    response = {
        'message': 'New nodes are added!',
        'total_nodes': list(blockchain.nodes)
    }
    print(blockchain.nodes)
    return jsonify(response), 201


# Endpoint to start the voting process
@app.route('/voting', methods=['GET'])
def voting():
    if port == 5000:
        show_votes = blockchain.add_vote()
        
        response = {
            'message': 'The voting results are as follows:',
            'nodes': blockchain.voteNodespool
        }
        
        return jsonify(response), 200
    
    else:
        response = {
            'message': 'You are not authorized to conduct the election process!'
        }
        return jsonify(response), 400


# Endpoint to view the list of all three elected delegate nodes
@app.route('/delegates/show', methods=['GET'])
def delegates():
    show_delegates = blockchain.selection()
    
    response = {
        'message': 'The 3 delegate nodes selected for block mining are:',
        'node_delegates': blockchain.delegates
    }
    return jsonify(response), 200


# Endpoint to synchronise the list of elected delegates with all other nodes in the network
@app.route('/delegates/sync', methods=['GET'])
def sync_delegates():
    sync_delegates = blockchain.sync()
    
    response = {
        'message': 'The delegate nodes are:',
        'node_delegates': blockchain.delegates
    }
    return jsonify(response), 200


# Endpoint to resolve and replace current chain with the longest validated one,achieving consensus
@app.route('/chain/resolve', methods=['GET'])
def consensus():
    replaced = blockchain.resolve_chain()
    
    if replaced:
        response = {
            'message': 'Our chain was replaced',
            'new_chain': blockchain.chain
        }
    else:
        response = {
            'message': 'Our chain is authoritative',
            'chain': blockchain.chain
        }
    return jsonify(response), 200


if __name__ == '__main__':
    from argparse import ArgumentParser
    
    parser = ArgumentParser()
    parser.add_argument('-p', '--port', default=5000, type=int, help='Listening on port')
    args = parser.parse_args()
    port = args.port
    app.run(host='0.0.0.0', port=port)