import { escapeHtml, fetchJson, formatBytes, inferEnhancementClass, inferEnhancementLabel } from '../common.js';
import { buildVolumeMap, isVideoMime, restoreSegmentBytes, supportsFileDownload } from '../media-core.js';

// 右侧详情面板：
//   - 选中文件 → 属性 + 内嵌 <video> 播放器 + 预览/下载按钮
//   - 选中数据源 → 源概况（移植 source.js renderSourceSummary）
//   - 空 → 提示
//
// 依赖注入：mediaPlayer(createMediaPlayer 实例)、resolveSecrets(异步返回凭据或抛出)、
//           feedback(createFeedbackController)、onThumbnailUpdated(回调刷新列表缩略图)

function isVideoFileInfo(fileInfo) {
  return Boolean(fileInfo && isVideoMime(fileInfo.file.mime));
}

export function createDetailPanel(rootElement, deps = {}) {
  const { mediaPlayer, resolveSecrets, feedback, onThumbnailUpdated } = deps;

  const state = {
    mode: 'empty',
    sourceId: null,
    entry: null,
    fileInfo: null,
    loadToken: 0
  };

  function renderEmpty(message = '选中一个文件或数据源查看详情。') {
    state.mode = 'empty';
    rootElement.innerHTML = `<div class="empty-state-card">${escapeHtml(message)}</div>`;
  }

  function renderSourceOverview(source) {
    state.mode = 'source';
    if (!source) {
      renderEmpty('未找到对应数据源。');
      return;
    }

    const enhancementError = source.enhancement?.lastErrorMessage
      ? `<div class="feedback feedback-error">最近失败：${escapeHtml(source.enhancement.lastErrorMessage)}</div>`
      : '';

    rootElement.innerHTML = `
      <div class="explorer-detail-head">
        <span class="explorer-detail-ico">💽</span>
        <div>
          <div class="explorer-detail-title serif">${escapeHtml(source.displayName || source.originalFilename)}</div>
          <div class="status-pill ${inferEnhancementClass(source)}">${inferEnhancementLabel(source)}</div>
        </div>
      </div>
      <hr>
      <div class="summary-stack">
        <div class="summary-row"><span>数据库文件</span><strong>${escapeHtml(source.originalFilename)}</strong></div>
        <div class="summary-row"><span>Source ID</span><strong>${escapeHtml(source.id)}</strong></div>
        <div class="summary-row"><span>上传大小</span><strong>${formatBytes(source.fileSize)}</strong></div>
        <div class="summary-row"><span>目录浏览</span><strong>${source.canBrowse ? '可用' : '不可用'}</strong></div>
        <div class="summary-row"><span>预览图缓存</span><strong>${escapeHtml(String(source.thumbnailCache?.count ?? 0))} 张</strong></div>
        <div class="summary-row"><span>最新快照</span><strong>${escapeHtml(source.latestSnapshot?.timestamp ?? '暂无')}</strong></div>
      </div>
      ${enhancementError}
      <div class="explorer-detail-actions">
        <button class="ghost-button explorer-pill" type="button" data-detail-action="props">⚙ 属性 / 增强配置</button>
      </div>
    `;
  }

  function renderFileLoading(entry) {
    state.mode = 'file';
    rootElement.innerHTML = `
      <div class="explorer-detail-head">
        <span class="explorer-detail-ico">📄</span>
        <div><div class="explorer-detail-title serif">${escapeHtml(entry.name)}</div></div>
      </div>
      <hr>
      <div class="summary-card">正在读取文件信息...</div>
    `;
  }

  function renderFile(entry, fileInfo, { error = null } = {}) {
    state.mode = 'file';
    const canPreview = isVideoFileInfo(fileInfo);
    const previewBlock = canPreview
      ? `
        <div class="explorer-preview-frame">
          <video id="detailVideo" controls playsinline preload="metadata"></video>
        </div>`
      : `
        <div class="explorer-preview-frame explorer-preview-static">
          ${
            entry.thumbnail?.available
              ? `<img src="${escapeHtml(entry.thumbnail.thumbnailUrl)}" alt="">`
              : '<span class="explorer-detail-ico-lg">📄</span>'
          }
        </div>`;

    const infoAvailable = Boolean(fileInfo);
    const errorBlock = error ? `<div class="feedback feedback-error">${escapeHtml(error)}</div>` : '';

    rootElement.innerHTML = `
      ${previewBlock}
      <div class="explorer-detail-title serif">${escapeHtml(entry.name)}</div>
      <hr>
      <div class="summary-stack">
        <div class="summary-row"><span>类型</span><strong>${escapeHtml(entry.mime || '未知')}</strong></div>
        <div class="summary-row"><span>大小</span><strong>${formatBytes(entry.size)}</strong></div>
        <div class="summary-row"><span>修改时间</span><strong>${escapeHtml(entry.mtime ?? '—')}</strong></div>
        <div class="summary-row"><span>路径</span><strong class="muted">${escapeHtml(entry.path)}</strong></div>
      </div>
      ${errorBlock}
      <div id="detailStatus" class="explorer-detail-status" hidden></div>
      <div class="explorer-detail-actions">
        ${canPreview ? '<button class="primary-button explorer-pill" type="button" data-detail-action="preview">▶ 预览</button>' : ''}
        <button class="ghost-button explorer-pill" type="button" data-detail-action="download" ${infoAvailable ? '' : 'disabled'}>↓ 下载</button>
      </div>
    `;
  }

  async function loadAndRenderFile(sourceId, entry) {
    state.sourceId = sourceId;
    state.entry = entry;
    state.fileInfo = null;
    const token = ++state.loadToken;

    renderFileLoading(entry);

    try {
      const payload = await fetchJson(
        `/api/file-info?sourceId=${encodeURIComponent(sourceId)}&id=${encodeURIComponent(entry.id)}`
      );
      if (token !== state.loadToken) {
        return;
      }
      state.fileInfo = payload;
      renderFile(entry, payload);
    } catch (error) {
      if (token !== state.loadToken) {
        return;
      }
      renderFile(entry, null, { error: error.message });
    }
  }

  function setDetailStatus(message) {
    const el = rootElement.querySelector('#detailStatus');
    if (!el) {
      return;
    }
    el.hidden = false;
    el.textContent = message;
  }

  async function startPreview() {
    const videoElement = rootElement.querySelector('#detailVideo');
    if (!videoElement || !state.fileInfo) {
      return;
    }
    try {
      const secrets = await resolveSecrets(state.sourceId, state.fileInfo);
      feedback?.set('info', '正在注册浏览器端媒体会话...');
      await mediaPlayer.play({
        videoElement,
        sourceId: state.sourceId,
        fileId: state.entry.id,
        fileInfo: state.fileInfo,
        secrets
      });
      feedback?.set('success', '视频预览已就绪，可播放并拖动进度。');
    } catch (error) {
      if (error?.code === 'CREDENTIALS_CANCELLED') {
        return;
      }
      feedback?.set('error', error.message);
    }
  }

  async function downloadFile() {
    if (!state.fileInfo) {
      return;
    }
    try {
      if (!supportsFileDownload()) {
        throw new Error('BROWSER_DOWNLOAD_UNSUPPORTED: 当前浏览器不支持 OPFS 或 showSaveFilePicker。');
      }
      const secrets = await resolveSecrets(state.sourceId, state.fileInfo);
      const fileInfo = state.fileInfo;
      const extension = fileInfo.file.name.includes('.') ? `.${fileInfo.file.name.split('.').pop()}` : '.bin';
      const fileHandle = await showSaveFilePicker({
        suggestedName: fileInfo.file.name,
        types: [
          {
            description: 'Restored file',
            accept: { [fileInfo.file.mime || 'application/octet-stream']: [extension] }
          }
        ]
      });

      feedback?.set('info', '正在浏览器直连下载...');
      const writable = await fileHandle.createWritable();
      const volumeByRef = buildVolumeMap(fileInfo.volumes);
      let writtenBytes = 0;

      for (const segment of fileInfo.segments) {
        const volume = volumeByRef.get(segment.volumeRef);
        setDetailStatus(`正在恢复卷 ${volume?.name ?? segment.volumeRef} · 已写入 ${formatBytes(writtenBytes)}`);
        const bytes = await restoreSegmentBytes({
          sourceId: state.sourceId,
          volume,
          zip: segment.zip,
          secrets,
          onStatus: ({ phase, currentVolume }) => {
            setDetailStatus(`${phase ?? '处理中'} · ${currentVolume ?? ''} · 已写入 ${formatBytes(writtenBytes)}`);
          }
        });
        await writable.write(bytes);
        writtenBytes += bytes.length;
      }

      await writable.close();
      setDetailStatus(`下载完成 · 共 ${formatBytes(writtenBytes)}`);
      feedback?.set('success', '文件已直接恢复并写入本地。');
    } catch (error) {
      if (error?.name === 'AbortError' || error?.code === 'CREDENTIALS_CANCELLED') {
        return;
      }
      setDetailStatus(error.message);
      feedback?.set('error', error.message);
    }
  }

  rootElement.addEventListener('click', (event) => {
    const button = event.target.closest('[data-detail-action]');
    if (!(button instanceof HTMLElement)) {
      return;
    }
    const action = button.dataset.detailAction;
    if (action === 'preview') {
      void startPreview();
    } else if (action === 'download') {
      void downloadFile();
    } else if (action === 'props') {
      deps.onOpenProps?.(state.sourceId);
    }
  });

  return {
    async showFile(sourceId, entry) {
      await mediaPlayer.stop();
      await loadAndRenderFile(sourceId, entry);
    },
    async showSource(source) {
      await mediaPlayer.stop();
      state.sourceId = source?.id ?? null;
      state.entry = null;
      state.fileInfo = null;
      renderSourceOverview(source);
    },
    async clear() {
      await mediaPlayer.stop();
      state.sourceId = null;
      state.entry = null;
      state.fileInfo = null;
      renderEmpty();
    },
    updateThumbnail(fileId, thumbnail) {
      if (state.entry?.id === fileId) {
        state.entry.thumbnail = thumbnail;
      }
      onThumbnailUpdated?.(fileId, thumbnail);
    }
  };
}