#!/usr/bin/env node
import http from 'node:http';
import fs from 'node:fs/promises';
import path from 'node:path';
import { URL } from 'node:url';
import { buildMoneyGraph, destinationTree, originTree, summarizeLedger } from './moneyGraph.js';
import { loadLedger, resolveAccountOwnerHints } from './ledgerStore.js';

const args = parseArgs(process.argv.slice(2));
const ledgerPath = args.ledger || 'data/example-ledger.json';
const port = Number(args.port || 3910);
const host = args.host || '127.0.0.1';
const webDir = path.resolve(args.web || 'web');

let ledger = resolveAccountOwnerHints(await loadLedger(ledgerPath));
let graph = buildMoneyGraph(ledger);

const MIME = {
  '.html': 'text/html; charset=utf-8',
  '.js':   'text/javascript; charset=utf-8',
  '.css':  'text/css; charset=utf-8',
  '.json': 'application/json; charset=utf-8',
  '.ico':  'image/x-icon',
};

const server = http.createServer(async (req, res) => {
  try {
    const url = new URL(req.url, `http://${req.headers.host}`);

    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
    if (req.method === 'OPTIONS') { res.writeHead(204); res.end(); return; }

    if (req.method === 'GET' && url.pathname === '/health') {
      return sendJson(res, { status: 'ok', service: 'kua-money-trace', ledger: ledgerPath });
    }

    if (req.method === 'POST' && url.pathname === '/reload') {
      ledger = resolveAccountOwnerHints(await loadLedger(ledgerPath));
      graph = buildMoneyGraph(ledger);
      return sendJson(res, { reloaded: true, summary: summarizeLedger(ledger, graph) });
    }

    if (req.method === 'GET' && url.pathname === '/summary') {
      return sendJson(res, summarizeLedger(ledger, graph));
    }

    if (req.method === 'GET' && url.pathname === '/entities') {
      return sendJson(res, { entities: ledger.entities });
    }

    if (req.method === 'GET' && url.pathname === '/accounts') {
      return sendJson(res, { accounts: ledger.accounts });
    }

    if (req.method === 'GET' && url.pathname === '/movements') {
      return sendJson(res, { movements: ledger.movements });
    }

    const originMatch = url.pathname.match(/^\/nodes\/(.+)\/origin-tree$/);
    if (req.method === 'GET' && originMatch) {
      return sendJson(res, originTree(graph, decodeURIComponent(originMatch[1])));
    }

    const destinationMatch = url.pathname.match(/^\/nodes\/(.+)\/destination-tree$/);
    if (req.method === 'GET' && destinationMatch) {
      return sendJson(res, destinationTree(graph, decodeURIComponent(destinationMatch[1])));
    }

    // static files from web/
    if (req.method === 'GET') {
      const filePath = path.join(webDir, url.pathname === '/' ? 'dashboard.html' : url.pathname);
      const realPath = path.resolve(filePath);
      if (!realPath.startsWith(webDir + path.sep) && realPath !== webDir) {
        return sendJson(res, { error: 'forbidden' }, 403);
      }
      try {
        const data = await fs.readFile(realPath);
        const ext = path.extname(realPath);
        res.writeHead(200, { 'content-type': MIME[ext] || 'application/octet-stream' });
        res.end(data);
        return;
      } catch {
        // fall through to 404
      }
    }

    sendJson(res, { error: 'not found' }, 404);
  } catch (error) {
    sendJson(res, { error: error.message }, 500);
  }
});

server.listen(port, host, () => {
  console.log(`kua-money-trace listening on http://${host}:${port}`);
  console.log(`  dashboard: http://${host}:${port}/dashboard.html`);
  console.log(`  ledger:    ${ledgerPath}`);
});

function sendJson(res, body, status = 200) {
  res.writeHead(status, { 'content-type': 'application/json; charset=utf-8' });
  res.end(JSON.stringify(body, null, 2));
}

function parseArgs(argv) {
  const parsed = {};
  for (let i = 0; i < argv.length; i += 1) {
    if (argv[i].startsWith('--')) {
      parsed[argv[i].slice(2)] = argv[i + 1];
      i += 1;
    }
  }
  return parsed;
}