/**
 * QZ Tray printing for Cantarire & Etichetare.
 *
 * Mirrors the working integration from `quality_app-v2`:
 *  - the patched `qz-tray.js` (2.2.4) that skips the certificate exchange and
 *    talks to a custom QZ Tray service using pairing-key auth;
 *  - `qz.printers.find()` + auto-selection of the thermal/label printer;
 *  - `qz.configs.create(printer, { scaleContent:false, rasterize:.., size, units:'mm' })`;
 *  - `qz.print(config, [{ type:'pdf'|'html', format:'base64'|'plain', data }])`.
 *
 * Public API (kept simple so the rest of the app does not care about QZ):
 *   window.CantarirePrint.print(payload)   -> Promise<{ok, method, printer?}>
 *   window.CantarireQZ                     -> status / connect / printers / test
 *
 * `payload` is produced by `cantarire/labels.py::print_payload`:
 *   { job_id, weighing_id, template:{width_mm,height_mm}, html, css,
 *     fields, print_url, ack_url, pdf_url? }
 *
 * If `pdf_url` is present the label is fetched as PDF and sent with
 * `type:'pdf'` (the exact flow used by quality_app-v2). Otherwise the HTML
 * label is rasterized by QZ Tray at the physical size from the template.
 */
(function () {
  'use strict';

  var STORAGE_KEY = 'cantarire.qz.printer';

  var config = Object.assign({
    autoConnect: true,
    fallbackToBrowser: true,
    connectTimeoutMs: 6000,
    storageKey: STORAGE_KEY,
    thermalHints: ['thermal', 'label', 'zebra', 'godex', 'argox', 'tsc', 'citizen',
                   'xprinter', 'bixolon', 'epson', 'datamax', 'sato'],
    // Optional: standard QZ Tray (with certificate + signature) instead of the
    // patched pairing-key service. Set via window.CANTARIRE_QZ before this file.
    certificateUrl: '',
    signatureUrl: ''
  }, window.CANTARIRE_QZ || {});

  var state = {
    status: 'idle',          // idle | connecting | ready | offline | missing
    connected: false,
    printers: [],
    printer: '',
    version: '',
    error: null,
    lastFailureAt: 0
  };

  var connectPromise = null;
  var lastRendered = '';

  // -- helpers -------------------------------------------------------------
  function lib() { return window.qz; }

  function snapshot() {
    return {
      status: state.status,
      connected: state.connected,
      printers: state.printers.slice(),
      printer: state.printer,
      version: state.version,
      error: state.error
    };
  }

  function messageOf(error) {
    if (!error) return 'Eroare necunoscuta';
    return error.message || String(error);
  }

  function setState(patch) {
    Object.assign(state, patch);
    emit();
  }

  function emit() {
    var detail = snapshot();
    try {
      document.dispatchEvent(new CustomEvent('cantarire:qz', { detail: detail }));
    } catch (error) { /* browsere foarte vechi */ }
    syncUi();
  }

  function savedPrinter() {
    try { return localStorage.getItem(config.storageKey) || ''; } catch (error) { return ''; }
  }

  function savePrinter(name) {
    try {
      if (name) localStorage.setItem(config.storageKey, name);
      else localStorage.removeItem(config.storageKey);
    } catch (error) { /* mod privat */ }
  }

  function choosePrinter(printers) {
    var saved = savedPrinter();
    if (saved && printers.indexOf(saved) >= 0) return saved;
    for (var i = 0; i < printers.length; i++) {
      var name = printers[i].toLowerCase();
      for (var j = 0; j < config.thermalHints.length; j++) {
        if (name.indexOf(config.thermalHints[j]) >= 0) return printers[i];
      }
    }
    return printers.length ? printers[0] : '';
  }

  function setupSecurity(qz) {
    if (config.certificateUrl && qz.security && qz.security.setCertificatePromise) {
      qz.security.setCertificatePromise(function (resolve, reject) {
        fetch(config.certificateUrl, { cache: 'no-store' }).then(function (response) {
          if (!response.ok) throw new Error('certificat: HTTP ' + response.status);
          return response.text();
        }).then(resolve, reject);
      }, { rejectOnFailure: true });
    }
    if (config.signatureUrl && qz.security && qz.security.setSignaturePromise) {
      qz.security.setSignaturePromise(function (toSign) {
        return function (resolve, reject) {
          fetch(config.signatureUrl, {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ request: toSign })
          }).then(function (response) {
            if (!response.ok) throw new Error('semnatura: HTTP ' + response.status);
            return response.text();
          }).then(resolve, reject);
        };
      });
    }
  }

  // -- connection ----------------------------------------------------------
  function connect() {
    if (state.connected) return Promise.resolve(true);
    if (connectPromise) return connectPromise;

    var qz = lib();
    if (!qz) {
      setState({
        status: 'missing',
        connected: false,
        error: 'Biblioteca qz-tray.js nu este incarcata.',
        version: ''
      });
      return Promise.resolve(false);
    }

    setState({ status: 'connecting', error: null });

    // The QZ client sweeps several hosts/ports before giving up; reflect a
    // failure in the UI early. A connection that succeeds later still wins.
    var timeout = Number(config.connectTimeoutMs) || 6000;
    var watchdog = setTimeout(function () {
      if (!state.connected && state.status === 'connecting') {
        setState({
          status: 'offline',
          error: 'QZ Tray nu a raspuns in ' + timeout + ' ms (agentul este pornit?).'
        });
      }
    }, timeout);

    connectPromise = Promise.resolve()
      .then(function () {
        try { setupSecurity(qz); } catch (error) { console.warn('[QZ] security:', error); }
        return qz.websocket.isActive() ? null : qz.websocket.connect();
      })
      .then(function () { return qz.api.getVersion(); })
      .then(function (version) {
        setState({ status: 'ready', connected: true, version: version, error: null });
        return loadPrinters();
      })
      .then(function () { return true; })
      .catch(function (error) {
        setState({
          status: 'offline',
          connected: false,
          version: '',
          error: messageOf(error),
          lastFailureAt: Date.now()
        });
        return false;
      })
      .finally(function () {
        clearTimeout(watchdog);
        connectPromise = null;
      });

    return connectPromise;
  }

  function disconnect() {
    var qz = lib();
    var done = qz && qz.websocket.isActive() ? qz.websocket.disconnect() : Promise.resolve();
    return Promise.resolve(done).catch(function () { /* ignoram */ }).then(function () {
      setState({ status: 'idle', connected: false, version: '', printers: [] });
      return false;
    });
  }

  function loadPrinters() {
    var qz = lib();
    if (!qz || !state.connected) return Promise.resolve([]);

    return qz.printers.find().then(function (found) {
      var list = Array.isArray(found) ? found.map(String) : (found ? [String(found)] : []);
      var chosen = choosePrinter(list);
      state.printers = list;
      state.printer = chosen;
      if (chosen) savePrinter(chosen);
      emit();
      return list;
    }).catch(function (error) {
      setState({ error: messageOf(error) });
      return [];
    });
  }

  function setPrinter(name) {
    state.printer = name || '';
    savePrinter(state.printer);
    emit();
  }

  // -- payload -------------------------------------------------------------
  function dimensions(payload) {
    var template = payload.template || {};
    var width = Number(template.width_mm);
    var height = Number(template.height_mm);
    return {
      width: isFinite(width) && width > 0 ? width : 100,
      height: isFinite(height) && height > 0 ? height : 60
    };
  }

  function labelDocument(payload) {
    var size = dimensions(payload);
    return '<!doctype html><html><head><meta charset="utf-8"><style>'
      + '@page{size:' + size.width + 'mm ' + size.height + 'mm;margin:0}'
      + 'html,body{margin:0;padding:0;width:' + size.width + 'mm;height:' + size.height
      + 'mm;overflow:hidden;background:#fff}'
      + '*,*::before,*::after{box-sizing:border-box}'
      + (payload.css || '')
      + '</style></head><body><div class="label-sheet" style="width:' + size.width
      + 'mm;height:' + size.height + 'mm;overflow:hidden">'
      + (payload.html || '')
      + '</div></body></html>';
  }

  function fetchBase64(url) {
    return fetch(url, { cache: 'no-store' }).then(function (response) {
      if (!response.ok) throw new Error('PDF: HTTP ' + response.status);
      return response.blob();
    }).then(function (blob) {
      return new Promise(function (resolve, reject) {
        var reader = new FileReader();
        reader.onloadend = function () {
          resolve(String(reader.result).split(',')[1]);
        };
        reader.onerror = reject;
        reader.readAsDataURL(blob);
      });
    });
  }

  function printPdf(qz, payload) {
    var size = dimensions(payload);
    var printerConfig = qz.configs.create(state.printer || '', {
      scaleContent: false,
      rasterize: false,
      size: { width: size.width, height: size.height },
      units: 'mm',
      margins: { top: 0, right: 0, bottom: 0, left: 0 }
    });
    return fetchBase64(payload.pdf_url).then(function (base64) {
      return qz.print(printerConfig, [{ type: 'pdf', format: 'base64', data: base64 }]);
    });
  }

  function printHtml(qz, payload) {
    var size = dimensions(payload);
    var printerConfig = qz.configs.create(state.printer || '', {
      scaleContent: false,
      rasterize: true,
      size: { width: size.width, height: size.height },
      units: 'mm',
      margins: { top: 0, right: 0, bottom: 0, left: 0 },
      interpolation: 'optimizeQuality'
    });
    return qz.print(printerConfig, [{
      type: 'html',
      format: 'plain',
      data: labelDocument(payload)
    }]);
  }

  function browserPrint(payload) {
    // On the label page itself, the browser dialog is exactly what we want.
    if (document.getElementById('label-sheet')) {
      window.print();
      return { ok: true, method: 'browser' };
    }

    // Anywhere else (dashboard), print the label page, not the current page.
    var url = payload && payload.print_url;
    if (url) {
      var frame = document.getElementById('print-frame');
      if (frame) {
        frame.src = url + '?auto=1';
        return { ok: true, method: 'browser', framed: true };
      }
      window.open(url + '?auto=1', '_blank', 'noopener');
      return { ok: true, method: 'browser' };
    }

    window.print();
    return { ok: true, method: 'browser' };
  }

  /**
   * Do not hold the operator for the full host/port sweep of the QZ client:
   * wait at most `connectTimeoutMs`, then let the caller fall back.
   * A connection that succeeds later is still used by the next print.
   */
  function ensureConnected() {
    if (state.connected) return Promise.resolve(true);

    // QZ was not running a moment ago: do not make every label wait again.
    if (state.status === 'offline' && state.lastFailureAt &&
        Date.now() - state.lastFailureAt < 30000) {
      return Promise.resolve(false);
    }

    var timeout = Number(config.connectTimeoutMs) || 6000;
    return Promise.race([
      connect(),
      new Promise(function (resolve) { setTimeout(function () { resolve(false); }, timeout); })
    ]);
  }

  // -- public print --------------------------------------------------------
  function print(payload) {
    payload = payload || {};

    return ensureConnected().then(function (connected) {
      if (!connected) {
        if (!config.fallbackToBrowser) {
          throw new Error(state.error || 'QZ Tray nu este disponibil.');
        }
        console.warn('[QZ] fallback la tiparirea din browser:', state.error);
        return browserPrint(payload);
      }

      var qz = lib();
      var job = payload.pdf_url
        ? printPdf(qz, payload).catch(function (error) {
            // PDF-ul poate lipsi (endpoint nedisponibil): incercam HTML-ul.
            console.warn('[QZ] PDF indisponibil, folosesc eticheta HTML:', error);
            return printHtml(qz, payload);
          })
        : printHtml(qz, payload);

      return job.then(function () {
        if (state.error) setState({ error: null });
        return { ok: true, method: 'qz', printer: state.printer };
      }).catch(function (error) {
        setState({ error: messageOf(error), lastFailureAt: Date.now() });
        if (!config.fallbackToBrowser) throw error;
        console.warn('[QZ] tiparirea a esuat, folosesc browserul:', error);
        return browserPrint(payload);
      });
    });
  }

  function printTest() {
    var stamp = new Date().toLocaleString('ro-RO');
    var payload = {
      template: { width_mm: 60, height_mm: 40 },
      css: '.t{font-family:Arial,sans-serif;text-align:center;padding:4mm;color:#000}'
        + '.t h1{font-size:5mm;margin:0 0 2mm}.t p{font-size:3.5mm;margin:1mm 0}',
      html: '<div class="t"><h1>TEST IMPRIMANTA</h1>'
        + '<p>' + (state.printer || 'imprimanta implicita') + '</p>'
        + '<p>' + stamp + '</p>'
        + '<p>Cantarire &amp; Etichetare</p></div>'
    };
    return print(payload);
  }

  // -- UI binding ----------------------------------------------------------
  function statusText() {
    if (state.status === 'ready') return 'QZ Tray: pregatit';
    if (state.status === 'connecting') return 'QZ Tray: conectare…';
    if (state.status === 'missing') return 'QZ Tray: biblioteca lipsa';
    if (state.status === 'offline') return 'QZ Tray: deconectat';
    return 'QZ Tray: neinitializat';
  }

  function renderPrinterSelect(select) {
    var signature = state.printers.join('|') + '#' + state.printer;
    if (select.getAttribute('data-qz-rendered') === signature) return;
    select.setAttribute('data-qz-rendered', signature);

    var current = state.printer || '';
    select.innerHTML = '';
    var auto = document.createElement('option');
    auto.value = '';
    auto.textContent = state.printers.length ? 'Implicit (sistem)' : 'Nicio imprimanta detectata';
    select.appendChild(auto);

    state.printers.forEach(function (name) {
      var option = document.createElement('option');
      option.value = name;
      option.textContent = name;
      if (name === current) option.selected = true;
      select.appendChild(option);
    });
    select.value = current;
    select.disabled = state.printers.length === 0;
  }

  function syncUi() {
    if (typeof document === 'undefined') return;

    document.querySelectorAll('[data-qz-status]').forEach(function (node) {
      node.textContent = statusText();
      var pill = node.closest('[data-qz-pill]');
      if (pill) pill.setAttribute('data-qz-state', state.status);
      if (state.error) node.title = state.error;
      else node.removeAttribute('title');
    });

    document.querySelectorAll('[data-qz-printer]').forEach(renderPrinterSelect);

    document.querySelectorAll('[data-qz-version]').forEach(function (node) {
      node.textContent = state.version ? 'v' + state.version : '';
    });

    document.querySelectorAll('[data-qz-connect]').forEach(function (node) {
      node.disabled = state.connected || state.status === 'connecting';
    });
  }

  function bindUi() {
    document.addEventListener('change', function (event) {
      var select = event.target.closest ? event.target.closest('[data-qz-printer]') : null;
      if (select) setPrinter(select.value);
    });

    document.addEventListener('click', function (event) {
      var target = event.target.closest ? event.target.closest('[data-qz-connect],[data-qz-test],[data-qz-refresh]') : null;
      if (!target) return;
      if (target.hasAttribute('data-qz-connect')) {
        event.preventDefault();
        connect();
      } else if (target.hasAttribute('data-qz-test')) {
        event.preventDefault();
        printTest().catch(function (error) { alert('Test esuat: ' + messageOf(error)); });
      } else if (target.hasAttribute('data-qz-refresh')) {
        event.preventDefault();
        if (!state.connected) connect();
        else loadPrinters();
      }
    });
  }

  // -- boot ----------------------------------------------------------------
  window.CantarireQZ = {
    getState: snapshot,
    connect: connect,
    disconnect: disconnect,
    refreshPrinters: loadPrinters,
    setPrinter: setPrinter,
    printTest: printTest
  };
  window.CantarirePrint = { print: print };

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', function () {
      bindUi();
      syncUi();
      if (config.autoConnect) connect();
    });
  } else {
    bindUi();
    syncUi();
    if (config.autoConnect) connect();
  }
})();