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import os,web3,json
from web3.auto import w3
from web3 import Web3, HTTPProvider
from eth_account.messages import encode_defunct

# Polygon Mumbai params
CHAIN_ID = os.environ['CHAIN_ID']
RPC_ENDPOINT = os.environ['RPC_ENDPOINT']

# Contract params
CONTRACT_ADDRESS = os.environ['CONTRACT_ADDRESS']
CONTRACT_ABI = """
[
	{
		"inputs": [
			{
				"internalType": "address",
				"name": "approved_submitter",
				"type": "address"
			},
			{
				"internalType": "string",
				"name": "ipfs_cid",
				"type": "string"
			}
		],
		"name": "add_to_training_set",
		"outputs": [],
		"stateMutability": "nonpayable",
		"type": "function"
	},
	{
		"inputs": [
			{
				"internalType": "address",
				"name": "owner",
				"type": "address"
			}
		],
		"name": "OwnableInvalidOwner",
		"type": "error"
	},
	{
		"inputs": [
			{
				"internalType": "address",
				"name": "account",
				"type": "address"
			}
		],
		"name": "OwnableUnauthorizedAccount",
		"type": "error"
	},
	{
		"anonymous": false,
		"inputs": [
			{
				"indexed": true,
				"internalType": "address",
				"name": "previousOwner",
				"type": "address"
			},
			{
				"indexed": true,
				"internalType": "address",
				"name": "newOwner",
				"type": "address"
			}
		],
		"name": "OwnershipTransferred",
		"type": "event"
	},
	{
		"inputs": [],
		"name": "renounceOwnership",
		"outputs": [],
		"stateMutability": "nonpayable",
		"type": "function"
	},
	{
		"inputs": [
			{
				"internalType": "address",
				"name": "newOwner",
				"type": "address"
			}
		],
		"name": "transferOwnership",
		"outputs": [],
		"stateMutability": "nonpayable",
		"type": "function"
	},
	{
		"inputs": [
			{
				"internalType": "address",
				"name": "approved_submitter",
				"type": "address"
			}
		],
		"name": "get_from_training_set",
		"outputs": [
			{
				"internalType": "string",
				"name": "",
				"type": "string"
			}
		],
		"stateMutability": "view",
		"type": "function"
	},
	{
		"inputs": [],
		"name": "owner",
		"outputs": [
			{
				"internalType": "address",
				"name": "",
				"type": "address"
			}
		],
		"stateMutability": "view",
		"type": "function"
	}
]
"""

def handler(event, context):
    params = event['queryStringParameters']
    print("Received those params:",params)
    
    cid = params['cid']
    sig = params['signature']
    message = encode_defunct(text=params['message'])
    signer_address = (w3.eth.account.recover_message(message, signature=sig)).lower()
    
    print("Message has been signed by this address:", signer_address)
  
    print("Will now check if this address has a mapping with the provided CID.")
    
    print("Connecting to web3 endpoint")
    web3 = Web3(HTTPProvider(RPC_ENDPOINT))
    
    print("Loading contract definition")
    abi= json.loads(CONTRACT_ABI)
    
    print("Loading contract")
    contract = web3.eth.contract(Web3.to_checksum_address(CONTRACT_ADDRESS), abi=abi)
    
    print("Querying contract")
    address = Web3.to_checksum_address(signer_address)
    allowed_cid = contract.functions.get_from_training_set(address).call()
    print("IPFS CID from {}: {}".format(signer_address, allowed_cid))
    
    response = {
        "isAuthorized": True,
        "context": {
            "signer": signer_address, "expected_cid": cid, "allowed_cid": allowed_cid
        }
    }
    
    if allowed_cid == cid:
        print("Authorization granted. Expected CID \"{}\" matches with Smart Contract data \"{}\"".format(cid,allowed_cid))
    else:
        print("ERROR: expected CID \"{}\" does not match with Smart Contract data \"{}\"".format(cid,allowed_cid))
        response["isAuthorized"] = False

    return response