// Download asset → import into the active Premiere project via UXP's
// `premierepro` module. This is what the CEP panel could no longer do
// (csInterface.evalScript callback was lost in PPro 26).

(function () {
  const Import = {};

  // Use UXP's Node-style fs for streaming writes (avoids buffering multi-GB
  // files in memory). `os` is a stripped subset — `os.tmpdir` is not exposed
  // in all UXP builds, so resolve the temp folder defensively below.
  const fs   = require('fs');
  const path = require('path');
  let   os; try { os = require('os'); } catch (_) { os = {}; }
  let   uxpFs;
  try { uxpFs = require('uxp').storage.localFileSystem; } catch (_) { uxpFs = null; }

  // Resolve a writable temp folder using whichever API this UXP build
  // actually exposes. Returns an absolute path string suitable for both
  // fs.createWriteStream and premierepro.Project.importFiles.
  async function getTempBase() {
    // 1. Node-style os.tmpdir (newer UXP, simplest case)
    try { if (os.tmpdir) { const t = os.tmpdir(); if (typeof t === 'string' && t.length) return t; } } catch (_) {}
    // 2. UXP storage API — documented portable approach
    if (uxpFs && uxpFs.getTemporaryFolder) {
      try { const tmp = await uxpFs.getTemporaryFolder(); if (tmp && tmp.nativePath) return tmp.nativePath; } catch (_) {}
    }
    // 3. Windows env vars (always set under PPro)
    try {
      const e = (typeof process !== 'undefined' && process.env) || {};
      if (e.TEMP) return e.TEMP;
      if (e.TMP)  return e.TMP;
      if (e.LOCALAPPDATA) return path.join(e.LOCALAPPDATA, 'Temp');
    } catch (_) {}
    // 4. Homedir + Windows-style fallback
    try { if (os.homedir) return path.join(os.homedir(), 'AppData', 'Local', 'Temp'); } catch (_) {}
    throw new Error('Could not determine a writable temp folder on this system');
  }

  async function tempPath(safeName) {
    const base = await getTempBase();
    return path.join(base, 'dragonflight-' + safeName);
  }

  // Stream the body of a fetch Response to a file on disk.
  // Returns the absolute path. Reports progress via onProgress({ received, total }).
  async function streamToFile(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;
    // Wrap close in a Promise so we don't resolve before the OS finishes
    // flushing — without this, importFiles can race the writer.
    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))) {
          // Backpressure — wait for drain so memory stays flat.
          await new Promise(r => out.once('drain', r));
        }
        received += value.byteLength;
        if (onProgress) onProgress({ received, total });
      }
    } finally {
      out.end();
    }
    await closed;
    return destPath;
  }

  // Manual-follow fetch for redirects: UXP strips Authorization across
  // origins (per Adobe security policy), so for any /api/... call that might
  // 302 to S3 we follow the redirect ourselves and DROP the Bearer header
  // on the next hop.
  async function fetchFollow(url, opts) {
    opts = opts || {};
    let current = url;
    let auth = (opts.headers || {})['Authorization'] || null;
    for (let hop = 0; hop < 5; hop++) {
      const r = await fetch(current, Object.assign({}, opts, { redirect: 'manual' }));
      if (r.status >= 300 && r.status < 400 && r.headers.get('location')) {
        const next = r.headers.get('location');
        const absNext = /^https?:\/\//i.test(next) ? next : new URL(next, current).toString();
        const sameHost = (new URL(absNext)).host === (new URL(current)).host;
        opts = Object.assign({}, opts, {
          headers: Object.assign({}, opts.headers || {}, sameHost ? {} : { Authorization: undefined }),
        });
        if (!sameHost) delete opts.headers.Authorization;
        current = absNext;
        continue;
      }
      return r;
    }
    throw new Error('Too many redirects');
  }

  // Find the new ProjectItem after importFiles. Premiere's UXP importFiles
  // returns only a boolean — we diff the rootItem.getItems() snapshot.
  // (Not currently used but available for callers that need the item.)
  Import.locateImported = async function (project, filename) {
    try {
      const root = await project.getRootItem();
      const items = await root.getItems();
      for (const it of items) {
        const name = await it.getName().catch(() => null);
        if (name && name === filename) return it;
      }
    } catch (_) {}
    return null;
  };

  // Talk to Premiere. Lazy-require so the module isn't loaded until the user
  // actually triggers an import (faster panel boot, clearer error if UXP host
  // is missing the API).
  function ppro() {
    if (Import._ppro) return Import._ppro;
    try { Import._ppro = require('premierepro'); }
    catch (e) { throw new Error('UXP premierepro module unavailable: ' + e.message); }
    return Import._ppro;
  }

  // Hand a downloaded file off to Premiere.
  Import.importIntoProject = async function (filePath) {
    const P = ppro();
    const project = await P.Project.getActiveProject();
    if (!project) throw new Error('No active Premiere project. Open or create a project first.');
    const root = await project.getRootItem();
    // suppressUI=true, targetBin=root, asNumberedStills=false.
    const ok = await project.importFiles([filePath], true, root, false);
    if (!ok) throw new Error('Premiere refused to import the file.');
    return true;
  };

  // ── Proxy import: /stream returns a same-host /video URL ──────────
  Import.proxy = async function (asset) {
    const safeName = UI.sanitizeFilename((asset.display_name || asset.filename || asset.id) + '.mp4');
    const dest = await 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 streamToFile(r, dest, ({ received, total }) => {
      const pct = total ? 10 + (received / total) * 75 : 10;
      UI.showProgress('Downloading ' + 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');
  };

  // ── Hi-Res import: /hires returns a presigned S3 URL on broadcastmgmt.cloud
  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 tempPath(safeName);

    UI.showProgress('Downloading ' + safeName + ' (' + UI.formatBytes(Number(info.file_size || 0)) + ')…', 8);
    // info.url is presigned S3 — DO NOT add Bearer (would break signature).
    const r = await fetchFollow(info.url, {});
    if (!r.ok) throw new Error('Download HTTP ' + r.status);

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

  window.Import = Import;
})();