<?php

// Class that communicates with various blockchains via HTTP
class AGC_Blockchain {

	// we set up a two call hierarchy to make the address verifier more robust
	public static function is_dirty_address($cryptoId, $address) {
		
		if ($cryptoId === 'BTC') {
			return self::check_dirty_bitcoin($address);
		}
		if ($cryptoId === 'LTC') {
			return self::check_dirty_litecoin($address);	
		}
	}

	public static function get_total_received_for_address($cryptoId, $address, $requiredConfirmations) {
		
		if ($cryptoId === 'BTC') {
			return self::get_bitcoin_received_by($address, $requiredConfirmations);
		}
		if ($cryptoId === 'LTC') {
			return self::get_litecoin_received_by($address, $requiredConfirmations);
		}
	}

	private static function check_dirty_bitcoin($address) {
		$userAgentString = self::get_user_agent_string();

		$requestOne = 'https://blockchain.info/q/getreceivedbyaddress/' . $address . '?confirmations=0';
		$requestTwo = 'https://blockexplorer.com/api/addr/' . $address . '/totalReceived';

		$args = array(
			'user-agent' => $userAgentString
		);
		
		$responseOne = wp_remote_get($requestOne, $args);
		
		$firstResponseError = false;
		
		// set this flag and only run logic for requestTwo since requestOne failed
		if ( is_wp_error( $responseOne ) || $responseOne['response']['code'] !== 200) {
			AGC_Util::log(__FILE__, __LINE__, 'ERROR: ' . print_r($responseOne, true));
			$firstResponseError = true;			
		}		
        
        // we know requestOne failed, so just return the results for requestTwo
		if ($firstResponseError) {
			$responseTwo = wp_remote_get($requestTwo, $args);
			if ( is_wp_error($responseTwo) || $responseTwo['response']['code'] !== 200) {
				AGC_Util::log(__FILE__, __LINE__, 'ERROR: ' . $responseTwo['response']['code']);
				throw new \Exception('Could not reach external services to verify electrum address is unused.');
			}

			$totalReceivedSatoshi = (float) json_decode($responseTwo['body']);
			return $totalReceivedSatoshi > 0;
		}
		
		$totalReceivedOne = (float) json_decode($responseOne['body']);

		// we just need one verification the address is dirty
		if ($totalReceivedOne > 0) {
			return true;
		}
		// since the API sometimes fails with a response of 0, we try again
		$responseTwo = wp_remote_get($requestTwo, $args);
		if ( is_wp_error($responseTwo) || $responseTwo['response']['code'] !== 200) {
			return $totalReceivedOne > 0;
		}

		$totalReceivedTwo = (float) json_decode($responseTwo['body']);

		return $totalReceivedTwo > 0;
	}

	private static function check_dirty_litecoin($address) {
		$userAgentString = self::get_user_agent_string();

		$requestOne = 'https://api.blockcypher.com/v1/ltc/main/addrs/' . $address . '?confirmations=0';
		$requestTwo = 'https://chain.so/api/v2/get_address_received/LTC/' . $address;

		$args = array(
			'user-agent' => $userAgentString
		);
		
		$responseOne = wp_remote_get($requestOne, $args);
		$requestOneFailed = false;

		if (is_wp_error($responseOne) || $responseOne['response']['code'] !== 200) {
			AGC_Util::log(__FILE__, __LINE__, 'ERROR: ' . $responseOne['response']['code']);
			$requestOneFailed = true;
		}

		if ($requestOneFailed) {
			
			$responseTwo = wp_remote_get($requestTwo, $args);

			if (is_wp_error($responseTwo) || $responseTwo['response']['code'] !== 200) {
				AGC_Util::log(__FILE__, __LINE__, 'ERROR: ' . $responseTwo['response']['code']);
				throw new \Exception('Could not reach external services to verify electrum address is unused.');
			}

			$unconfirmedAmount = (float) json_decode($responseTwo['body'])->data->unconfirmed_received_value;
			$confirmedAmount = (float) json_decode($responseTwo['body'])->data->confirmed_received_value;

			$totalReceivedTwo = $unconfirmedAmount + $confirmedAmount;

			return $totalReceivedTwo > 0;
		}		
		
		$totalReceivedOne = json_decode($responseOne['body'])->total_received;

		if ($totalReceivedOne > 0) {
			return true;
		}
		
		$responseTwo = wp_remote_get($requestTwo, $args);

		if (is_wp_error($responseTwo) || $responseTwo['response']['code'] !== 200) {
			return $totalReceivedOne > 0;
		}

		$unconfirmedAmount = (float) json_decode($responseTwo['body'])->data->unconfirmed_received_value;
		$confirmedAmount = (float) json_decode($responseTwo['body'])->data->confirmed_received_value;

		$totalReceivedTwo = $unconfirmedAmount + $confirmedAmount;

		return $totalReceivedTwo > 0;
	}

	private static function get_bitcoin_received_by($address, $requiredConfirmations) {
		$userAgentString = self::get_user_agent_string();

		$request = 'https://blockchain.info/q/getreceivedbyaddress/' . $address . '?confirmations=' . $requiredConfirmations;	
			
		$args = array(
			'user-agent' => $userAgentString
		);
		
		$response = wp_remote_get($request, $args);
		
		if ( is_wp_error( $response ) || $response['response']['code'] !== 200) {
			AGC_Util::log(__FILE__, __LINE__, 'ERROR: ' . $response['response']['code']);
            throw new \Exception('Could not reach external services to verify electrum address total received.');
        }
        
		$totalReceivedSatoshi = (float) json_decode($response['body']);
		$totalReceived = $totalReceivedSatoshi / 100000000;

		return $totalReceived;
	}

	private static function get_litecoin_received_by($address, $requiredConfirmations) {
		$userAgentString = self::get_user_agent_string();

		$requestOne = 'https://api.blockcypher.com/v1/ltc/main/addrs/' . $address . '?confirmations=' . $requiredConfirmations;
		$requestTwo = 'https://chain.so/api/v2/get_address_received/LTC/' . $address;

		$args = array(
			'user-agent' => $userAgentString
		);

		$responseOne = wp_remote_get($requestOne, $args);

		$requestOneFailure = false;

		if (is_wp_error($responseOne) || $responseOne['response']['code'] !== 200) {
			AGC_Util::log(__FILE__, __LINE__, 'ERROR: ' . $responseOne['response']['code']);
			$requestOneFailure = true;
		}

		if ($requestOneFailure) {
			AGC_Util::log(__FILE__, __LINE__, 'calling received by: ' . $requestTwo);
			$responseTwo = wp_remote_get($requestTwo, $args);
			if (is_wp_error($responseTwo) || $responseTwo['response']['code'] !== 200) {
				AGC_Util::log(__FILE__, __LINE__, 'ERROR: ' . $responseTwo['response']['code']);
				throw new \Exception('Could not reach external services to verify electrum address total received.');
			}

			$unconfirmedAmount = (float) json_decode($responseTwo['body'])->data->unconfirmed_received_value;
			$confirmedAmount = (float) json_decode($responseTwo['body'])->data->confirmed_received_value;
			$totalReceived = $confirmedAmount;
			return $totalReceived;
		}

		$totalReceivedMmltc = json_decode($responseOne['body'])->total_received;
		$totalReceived = $totalReceivedMmltc / 100000000;

		return $totalReceived;
	}

	public static function verify_exact_ether_transaction_amount($address, $amount, $requiredConfirmations) {
		$request = 'http://api.etherscan.io/api?module=account&action=txlist&address=' . $address . '&startblock=0&endblock=99999999&sort=asc';

		$response = wp_remote_get($request);

		if (is_wp_error($response) || $response['response']['code'] !== 200) {
			throw new \Exception('Count not reach external services to verify ether transaction.');
		}

		$body = json_decode($response['body']);

		$transactions = $body->result;

		foreach ($transactions as $transaction) {
			$confirmations = $transaction->confirmations;

			if ($confirmations >= $requiredConfirmations) {

				$etherToMatch = 1000000000000000000 * $amount;
				

				if (abs($etherToMatch - $transaction->value) < 1) {
					AGC_Util::log(__FILE__, __LINE__, 'We found a matching transaction for an order... Transaction hash: ' . $transaction->hash);
					return $transaction->hash;
				}
			}
		}

		return '';
	}

	private static function get_user_agent_string() {
		return 'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.12 (KHTML, like Gecko) Chrome/9.0.576.0 Safari/534.12';
	}
}

?>