const fs = require('fs');

const worker = async (filename) => {
  console.log(`Reading ${filename}`);
  fs.readFile(filename, (err, data) => {
    if (err) throw err;
    const lines = data.toString().split('\n');
    const currencies = {};
    const accounts = {};
    const openingBalances = [];
    let records = [];
    let i = 0, line, parts;
    line = lines[i];

    const fullname = (account, name) => {
      if (account.parent > 0) {
        return fullname(accounts[account.parent], accounts[account.parent].name + ':' + name);
      } else {
        let cat;
        if (account.type === 2) cat = 'Income';
        if (account.type === 3) cat = 'Expense';
        if (account.type === 4 || account.type === 9) cat = 'Assets';
        if (account.liab) cat = 'Liabilities';
        return cat + ':' + name;
      }
    }

    const sanitize = (str) => {
      return str.replace(/"/g, '');
    }
    while (i < lines.length - 1) {
      if (line.startsWith('[currency]')) {
        line = lines[++i];
        while (!line.startsWith('[') && i < lines.length) {
          parts = line.split(';');
          currencies[parts[0]] = { ticker: sanitize(parts[3]), name: sanitize(parts[1]) }
          line = lines[++i];
        }
      } else if (line.startsWith('[objects]')) {
        line = lines[++i];
        while (!line.startsWith('[') && i < lines.length) {
          parts = line.split(';');
          accounts[parts[0]] = {
            name: sanitize(parts[3]),
            parent: parts[1],
            type: parseInt(parts[2]),
            liab: parts[7] === 't'
          }
          line = lines[++i];
        }
      } else if (line.startsWith('[records]')) {
          Object.keys(accounts).map((k, i) => {
            accounts[k].fullname = fullname(accounts[k], accounts[k].name);
          });

          line = lines[++i];
          while (line && !line.startsWith('[') && i < lines.length) {
            parts = line.split(';');
            if (parts.length > 4 && !parts[2].startsWith("-1")) {
              let account = accounts[parts[3]];
              let to = accounts[parts[2]];
              const amount = parseFloat(parts[0]) / 100;
              if (to.type === 2 || (to.type === 3 && amount > 0) ) { // income or rebate
                let sw = account;
                account = to;
                to = sw;
              }
              const isExpense = to.type === 3 && amount < 0;
              const date = new Date(parts[4]);
              const comment = sanitize(parts[5]);
              const prevRecord = records[records.length - 1];
              if (prevRecord
                  && prevRecord.date.getTime() === date.getTime()
                  && prevRecord.comment === comment
                  && prevRecord.from === to.fullname && prevRecord.to === account.fullname
                  && prevRecord.amount * amount < 0
                ) {
                prevRecord.transfer = true;
                if (prevRecord.amount > 0) {
                  prevRecord.inAmount = amount;
                  prevRecord.inCurrency = currencies[parts[1]].ticker;
                  const sw = prevRecord.from;
                  prevRecord.from = prevRecord.to;
                  prevRecord.to = sw;
                } else {
                  prevRecord.inAmount = prevRecord.amount;
                  prevRecord.inCurrency = prevRecord.currency;
                  prevRecord.amount = amount;
                  prevRecord.currency = currencies[parts[1]].ticker;
                }
              } else {
                records.push({
                  amount: isExpense ? Math.abs(amount) : amount,
                  date,
                  comment,
                  from: account.fullname,
                  to: to.fullname,
                  expense: isExpense,
                  currency: currencies[parts[1]].ticker
                });
              }
            } else if (parts[2].startsWith("-1")) {
              openingBalances.push({
                amount: parseFloat(parts[0]) / 100,
                acc: accounts[parts[3]].fullname,
                currency: currencies[parts[1]].ticker,
                date: new Date(parts[4])
              });
            }
            line = lines[++i];
          }
      }
    }

    require('fs').writeFile('data.ledger', records.map(r => JSON.stringify(r, null, 2)).join('\n\r'), (err) => {
      if (err) return console.log(err);
      console.log(`Saved`);
    });

    const pad = (i) => {
      if (i.toString().length == 1) return "0" + i;
      return i;
    }

    ledgerRecords = records.reverse().map(r => {
      let rec = `
${r.date.getFullYear()}/${pad(r.date.getMonth() + 1)}/${pad(r.date.getDate())} ${r.comment}
    ${r.to}       ${r.amount} ${r.currency}
    ${r.from}`;
      if (r.inAmount) {
        rec += '\t\t\t\t' + `${r.inAmount} ${r.inCurrency}`;
      }
      return rec;
    });

    let ledgerOpening = openingBalances.map(b => {
      return `
    ${b.acc}       ${b.amount} ${b.currency}`;
    });

    ledgerOpening = `
2001/01/01 * Opening Balance`
 + ledgerOpening.join('') + `
    Equity:Opening Balances`;

    require('fs').writeFile('t.dat', ledgerOpening + '\n\r\n\r' + ledgerRecords.join('\n\r\n\r'), (err) => {
      if (err) return console.log(err);
      console.log(`Saved`);
    });


  });
}

worker(process.argv[2]);