#!/usr/bin/php
<?php

$bank = "Assets:Checking\t\t\t\t\t";
$kraken = "Assets:Kraken\t\t\t\t\t";
$wallet = "Assets:Wallet\t\t\t\t\t";
$wfee = "Expenses:WithdrawalFees\t\t\t\t";
$dfee = "Expenses:DepositFees\t\t\t\t";
$tfee = "Expenses:TradingFees\t\t\t\t";

$transactions = array();

$json = file_get_contents("php://stdin");
$data = json_decode($json, true);

function dereference_asset($in) {
	$assets = array( 'ZEUR' => 'KEUR', 'XXBT' => 'BTC' );
	if (array_key_exists($in, $assets)) return $assets[$in];
	else die('unknown asset '.$in."\n");
	return $in;
}

function parse_to_int($string, $currency) {
	switch($currency) {
	case 'BTC':
		if (preg_match('/(-?)(\d+)\.(\d{8})00/', $string, $match)) {
			return intval($match[1].$match[2].$match[3]);
		} else die('unparsable BTC amount'."\n");
		break;
	case 'KEUR':
		if (preg_match('/(-?)(\d+)\.(\d{4})/', $string, $match)) {
			return intval($match[1].$match[2].$match[3]);
		} else die('unparsable KEUR amount'."\n");
		break;
	default:
		die("unknown asset type {$t['type']}\n");
	}
}

function convert_KEUR2EUR($in) {
	if ($in%100) die("unable to convert, because input has fractional cents\n");
	return intdiv($in, 100);
}

function print_from_int($in, $asset) {
	switch ($asset) {
	case 'BTC':
		$dec = 8;
		break;
	case 'KEUR':
		$dec = 4;
		break;
	case 'EUR':
		$dec = 2;
		break;
	default:
		die("unknown asset type $asset\n");
	}
	$negative = 0;
	if ($in < 0) {
		$negative = 1;
		$in *= -1;
	}

	$d = pow(10, $dec);
	$whole = intdiv($in, $d);
	$frac = $in%$d;
	return (($negative?'-':' ')).$whole.'.'.str_pad($frac, $dec, '0', STR_PAD_LEFT);
}

foreach ($data['result']['ledger'] as $key => $entry) {
	$refid = $entry['refid'];
	if (!array_key_exists($refid, $transactions)) {
		//echo("new refid $refid\n");
		$transactions[$refid] = array('type' => $entry['type'], 'postings' => array());
	}
	if ($entry['aclass'] != 'currency') continue;
	$asset = dereference_asset($entry['asset']);
	$transactions[$refid]['postings'][$key] = array(
		'time' => $entry['time'],
		'asset' => $asset,
		'amount' => parse_to_int($entry['amount'], $asset),
		'fee' => parse_to_int($entry['fee'], $asset),
		'balance' => parse_to_int($entry['balance'], $asset)
	);
	//print_r($entry);
	//print_r($transactions[$refid]);
}

function avgtime($postings) {
	$count = 0;
	$time = 0;
	foreach ($postings as $p) {
		$time += $p['time'];
		$count++;
	}
	if ($count == 0) die('no data to compute average'."\n");
	return $time/$count;
}

foreach (array_reverse($transactions) as $key => $t) {
	$postings = $t['postings'];
	$date= date('Y/m/d', avgtime($postings));
	echo("; $key\n");
	echo("$date * Kraken\n");
	switch ($t['type']) {
	case 'deposit':
		if (count($postings) != 1) die("unsuppored amount of postings in deposit\n");
		$id = array_key_first($postings);
		$posting = array_shift($postings);
		echo("\t; $id\n");
		switch ($posting['asset']) {
		case 'KEUR':
			echo("\t{$bank}EUR".print_from_int(convert_KEUR2EUR(-$posting['amount']), 'EUR')."\n");
			echo("\t{$kraken}KEUR".print_from_int($posting['amount'], 'KEUR')." = KEUR".print_from_int($posting['balance'], 'KEUR')."\n");
			if ($posting['fee'] != 0) die("unexpected deposit fee\n");
			break;
		default:
			die("unsupported asset for deposit {$posting['asset']}\n");
		}
		break;
	case 'withdrawal':
		if (count($postings) != 1) die("unsupported amount of postings in withdrawal\n");
		$id = array_key_first($postings);
		$posting = array_shift($postings);
		echo("\t; $id\n");
		switch ($posting['asset']) {
		case 'BTC':
			echo("\t{$kraken}BTC".print_from_int($posting['amount'] - $posting['fee'], 'BTC')." = BTC".print_from_int($posting['balance'], 'BTC')."\n");
			echo("\t{$wallet}BTC".print_from_int(-$posting['amount'], 'BTC')."\n");
			echo("\t{$wfee}BTC".print_from_int($posting['fee'], 'BTC')."\n");
			break;
		default:
			die("unsupported asset for withdrawel {$posting['asset']}\n");
		}
		break;
	case 'trade':
		if (count($postings) != 2) {
			//print_r($postings);
			echo("WARNING: unsupported amount of postings in trade\n");
			continue;
		}
		foreach ($postings as $id => $posting) {
			echo("\t; $id\n");
			switch ($posting['asset']) {
			case 'BTC':
				if ($posting['amount'] < 0) die("selling BTC not yet implemented\n");
				if ($posting['fee'] > 0) die("nonzero fee on BTC side while buying BTC not supported");
				echo("\t{$kraken}BTC".print_from_int($posting['amount'], 'BTC')." = BTC".print_from_int($posting['balance'], 'BTC')."\n");
				break;
			case 'KEUR':
				if ($posting['amount'] > 0) die("buying KEUR not yet implemented\n");
				echo("\t{$kraken}KEUR".print_from_int($posting['amount'] - $posting['fee'], 'KEUR')." = KEUR".print_from_int($posting['balance'], 'KEUR')."\n");
				echo("\t{$tfee}KEUR".print_from_int($posting['fee'], 'KEUR')."\n");
				break;
			}
		}
		//print_r($postings);
		break;
	default:
		die("unknown transaction type {$t['type']}\n");
	}
	echo("\n");
}
//print_r($transactions);
?>