// import-flow.js — v2.1.2
// Download asset → write to temp → importFiles() via UXP premierepro.
// NOTE: `path` module is NOT available in PPro 26 UXP. Use _join() helper.
// Also exposes _tempPath / _streamToFile for timeline.js batch relink.

(function () {
  const Import = {};

  const fs = require('fs');
  // `path` is stripped in this UXP build — manual join instead.
  let os; try { os = require('os'); } catch (_) { os = {}; }
  let uxpFs; try { uxpFs = require('uxp').storage.localFileSystem; } catch (_) { uxpFs = null; }

  // Simple path join that works on Windows (backslash) without require('path').
  function _join(base, name) {
    const sep = base.indexOf('/') === -1 ? '\\' : '/';
    return base.replace(/[\\/]+$/, '') + sep + name;
  }

  // ── Temp folder ──────────────────────────────────────────────────
  async function _getTempBase() {
    // 1. os.tmpdir (may exist in some UXP builds)
    try { if (os.tmpdir) { const t = os.tmpdir(); if (typeof t === 'string' && t.length) return t; } } catch (_) {}
    // 2. UXP storage API
    if (uxpFs && uxpFs.getTemporaryFolder) {
      try { const tmp = await uxpFs.getTemporaryFolder(); if (tmp && tmp.nativePath) return tmp.nativePath; } catch (_) {}
    }
    // 3. Windows env vars (always present under PPro on Windows)
    try {
      const e = (typeof process !== 'undefined' && process.env) || {};
      if (e.TEMP) return e.TEMP;
      if (e.TMP)  return e.TMP;
      if (e.LOCALAPPDATA) return e.LOCALAPPDATA + '\\Temp';
    } catch (_) {}
    // 4. Homedir fallback (no path.join needed)
    try { if (os.homedir) { const h = os.homedir(); if (h) return h + '\\AppData\\Local\\Temp'; } } catch (_) {}
    throw new Error('Cannot find writable temp folder');
  }

  Import._tempPath = async function (safeName) {
    const base = await _getTempBase();
    return _join(base, 'dragonflight-' + safeName);
  };

  // ── Stream response body to disk ─────────────────────────────────
  Import._streamToFile = async function (response, destPath, onProgress) {
    const total  = Number(response.headers.get('content-length') || 0);
    const reader = response.body.getReader();
    const out    = fs.createWriteStream(destPath);
    let received = 0;
    const closed = new Promise((resolve, reject) => {
      out.on('finish', resolve);
      out.on('error',  reject);
    });
    try {
      while (true) {
        const { value, done } = await reader.read();
        if (done) break;
        if (!out.write(Buffer.from(value))) {
          await new Promise(r => out.once('drain', r));
        }
        received += value.byteLength;
        if (onProgress) onProgress({ received, total });
      }
    } finally {
      out.end();
    }
    await closed;
    return destPath;
  };

  // ── Manual redirect follow ───────────────────────────────────────
  async function _fetchFollow(url, opts) {
    opts = opts || {};
    let current = url;
    for (let hop = 0; hop < 6; hop++) {
      const r = await fetch(current, Object.assign({}, opts, { redirect: 'manual' }));
      if (r.status >= 200 && r.status < 300) return r;
      if (r.status >= 300 && r.status < 400) {
        const loc = r.headers.get('location');
        if (!loc) throw new Error('Redirect with no Location');
        const next = /^https?:\/\//i.test(loc) ? loc : new URL(loc, current).toString();
        if (new URL(next).host !== new URL(current).host) {
          opts = Object.assign({}, opts, { headers: Object.assign({}, opts.headers || {}) });
          delete opts.headers['Authorization'];
        }
        current = next;
        continue;
      }
      throw new Error('HTTP ' + r.status);
    }
    throw new Error('Too many redirects');
  }

  // ── premierepro lazy require ─────────────────────────────────────
  function _ppro() {
    if (Import._ppro_mod) return Import._ppro_mod;
    try { Import._ppro_mod = require('premierepro'); }
    catch (e) { throw new Error('UXP premierepro unavailable: ' + e.message); }
    return Import._ppro_mod;
  }

  Import.importIntoProject = async function (filePath) {
    const P = _ppro();
    const project = await P.Project.getActiveProject();
    if (!project) throw new Error('No active Premiere project');
    const root = await project.getRootItem();
    const ok = await project.importFiles([filePath], true, root, false);
    if (!ok) throw new Error('Premiere refused to import file');
    return true;
  };

  // ── Proxy import ─────────────────────────────────────────────────
  Import.proxy = async function (asset) {
    const safeName = UI.sanitizeFilename((asset.display_name || asset.filename || asset.id) + '.mp4');
    const dest     = await Import._tempPath(safeName);

    UI.showProgress('Resolving proxy URL…', 4);
    const { url } = await API.getProxyUrl(asset.id);

    UI.showProgress('Downloading ' + safeName + '…', 10);
    const r = await _fetchFollow(url, { headers: { Authorization: 'Bearer ' + API.state.apiToken } });
    if (!r.ok) throw new Error('Download HTTP ' + r.status);

    await Import._streamToFile(r, dest, ({ received, total }) => {
      const pct = total ? 10 + (received / total) * 75 : 10;
      UI.showProgress(UI.formatBytes(received) + (total ? ' / ' + UI.formatBytes(total) : '') + '…', pct);
    });

    UI.showProgress('Importing into Premiere…', 92);
    await Import.importIntoProject(dest);
    UI.hideProgress();
    UI.toast('Imported: ' + safeName, 'ok');
    return { localPath: dest, safeName };
  };

  // ── Hi-Res import ────────────────────────────────────────────────
  Import.hires = async function (asset) {
    UI.showProgress('Resolving hi-res URL…', 4);
    const info     = await API.getHiresInfo(asset.id);
    const safeName = UI.sanitizeFilename(info.filename || (asset.display_name || asset.id) + '.' + (info.ext || 'mxf'));
    const dest     = await Import._tempPath(safeName);

    UI.showProgress('Downloading ' + safeName + ' (' + UI.formatBytes(Number(info.file_size || 0)) + ')…', 8);
    const r = await _fetchFollow(info.url, {});
    if (!r.ok) throw new Error('Download HTTP ' + r.status);

    await Import._streamToFile(r, dest, ({ received, total }) => {
      const pct = total ? 8 + (received / total) * 80 : 8;
      UI.showProgress(UI.formatBytes(received) + (total ? ' / ' + UI.formatBytes(total) : '') + '…', pct);
    });

    UI.showProgress('Importing into Premiere…', 92);
    await Import.importIntoProject(dest);
    UI.hideProgress();
    UI.toast('Hi-res imported: ' + safeName, 'ok');
    return { localPath: dest, safeName };
  };

  window.Import = Import;
})();