import { escapeHtml, formatBytes } from '../common.js';

// 文件列表组件：列表(表格) + 网格双视图、列头/下拉排序、多选、缩略图。
// 移植自 source.js 的 renderBrowse / 批量选择逻辑，改造成表格与网格。
// 事件回调：onOpenDir(path) / onOpenFile(entry) / onSelectFile(entry) / onSelectionChange(set)

function isVideoEntry(entry) {
  return String(entry.mime ?? '').toLowerCase().startsWith('video/') || entry.hints?.preview === 'video';
}

function typeLabel(entry) {
  if (entry.type === 'dir') {
    return '文件夹';
  }
  if (entry.hints?.preview) {
    return entry.hints.preview;
  }
  return (entry.mime || 'file').split('/').pop();
}

function thumbInner(entry) {
  if (entry.type === 'dir') {
    return '<span class="explorer-thumb-ico">📁</span>';
  }
  if (entry.thumbnail?.available) {
    return `<img src="${escapeHtml(entry.thumbnail.thumbnailUrl)}" alt="" loading="lazy">`;
  }
  if (isVideoEntry(entry)) {
    return '<span class="explorer-thumb-ico">🎬</span>';
  }
  if (String(entry.mime ?? '').startsWith('image/')) {
    return '<span class="explorer-thumb-ico">🖼</span>';
  }
  return '<span class="explorer-thumb-ico">📄</span>';
}

function compareEntries(a, b, sortKey, sortDir) {
  // 文件夹永远排在文件前面（与后端 sortEntries 一致）
  if (a.type !== b.type) {
    return a.type === 'dir' ? -1 : 1;
  }

  let result = 0;
  switch (sortKey) {
    case 'size':
      result = (Number(a.size) || 0) - (Number(b.size) || 0);
      break;
    case 'type':
      result = typeLabel(a).localeCompare(typeLabel(b), 'en');
      break;
    case 'mtime':
      result = String(a.mtime ?? '').localeCompare(String(b.mtime ?? ''));
      break;
    case 'name':
    default:
      result = a.name.localeCompare(b.name, 'zh-Hans-CN');
      break;
  }

  return sortDir === 'desc' ? -result : result;
}

export function createFileList(rootElement, handlers = {}) {
  const { onOpenDir, onOpenFile, onSelectFile, onSelectionChange } = handlers;

  const state = {
    entries: [],
    view: 'list',
    sortKey: 'name',
    sortDir: 'asc',
    filter: '',
    selected: new Set(),
    activeFileId: null
  };

  function visibleEntries() {
    const filter = state.filter.trim().toLowerCase();
    const filtered = filter
      ? state.entries.filter((entry) => entry.name.toLowerCase().includes(filter))
      : state.entries.slice();
    return filtered.sort((a, b) => compareEntries(a, b, state.sortKey, state.sortDir));
  }

  function fileEntries() {
    return state.entries.filter((entry) => entry.type === 'file');
  }

  function renderRows(entries) {
    return entries
      .map((entry) => {
        const selected = entry.type === 'file' && state.selected.has(entry.id);
        const active = entry.type === 'file' && entry.id === state.activeFileId;
        const rowClasses = [
          'explorer-row',
          entry.type === 'dir' ? 'is-dir' : 'is-file',
          selected ? 'selected' : '',
          active ? 'active' : ''
        ]
          .filter(Boolean)
          .join(' ');

        const checkboxCell =
          entry.type === 'file'
            ? `<input type="checkbox" class="explorer-row-check" data-file-id="${escapeHtml(entry.id)}" ${selected ? 'checked' : ''} aria-label="选择 ${escapeHtml(entry.name)}">`
            : '';

        const dataAttrs =
          entry.type === 'dir'
            ? `data-type="dir" data-path="${escapeHtml(entry.path)}"`
            : `data-type="file" data-file-id="${escapeHtml(entry.id)}"`;

        return `
          <tr class="${rowClasses}" ${dataAttrs}>
            <td class="explorer-col-chk">${checkboxCell}</td>
            <td>
              <div class="explorer-name-cell">
                <span class="explorer-thumb${entry.type === 'dir' ? ' folder' : ''}">
                  ${thumbInner(entry)}${isVideoEntry(entry) ? '<span class="explorer-play">▶</span>' : ''}
                </span>
                <span class="explorer-name-txt">${escapeHtml(entry.name)}</span>
              </div>
            </td>
            <td class="explorer-col-size">${entry.type === 'dir' ? '—' : formatBytes(entry.size)}</td>
            <td class="explorer-col-type"><span class="explorer-badge-type">${escapeHtml(typeLabel(entry))}</span></td>
            <td class="explorer-col-time muted">${escapeHtml(entry.mtime ?? '—')}</td>
          </tr>
        `;
      })
      .join('');
  }

  function renderCards(entries) {
    return entries
      .map((entry) => {
        const selected = entry.type === 'file' && state.selected.has(entry.id);
        const active = entry.type === 'file' && entry.id === state.activeFileId;
        const cardClasses = [
          'explorer-card',
          entry.type === 'dir' ? 'is-dir' : 'is-file',
          selected ? 'selected' : '',
          active ? 'active' : ''
        ]
          .filter(Boolean)
          .join(' ');

        const dataAttrs =
          entry.type === 'dir'
            ? `data-type="dir" data-path="${escapeHtml(entry.path)}"`
            : `data-type="file" data-file-id="${escapeHtml(entry.id)}"`;

        const checkbox =
          entry.type === 'file'
            ? `<input type="checkbox" class="explorer-row-check explorer-card-check" data-file-id="${escapeHtml(entry.id)}" ${selected ? 'checked' : ''} aria-label="选择 ${escapeHtml(entry.name)}">`
            : '';

        return `
          <div class="${cardClasses}" ${dataAttrs}>
            ${checkbox}
            <div class="explorer-cover${entry.type === 'dir' ? ' folder' : ''}">
              ${thumbInner(entry)}${isVideoEntry(entry) ? '<span class="explorer-play-lg">▶</span>' : ''}
            </div>
            <div class="explorer-card-cap" title="${escapeHtml(entry.name)}">${escapeHtml(entry.name)}</div>
            <div class="explorer-card-sub">${entry.type === 'dir' ? '文件夹' : formatBytes(entry.size)}</div>
          </div>
        `;
      })
      .join('');
  }

  function sortArrow(key) {
    if (state.sortKey !== key) {
      return '';
    }
    return `<span class="explorer-arrow">${state.sortDir === 'asc' ? '▲' : '▼'}</span>`;
  }

  function render() {
    const entries = visibleEntries();

    if (state.entries.length === 0) {
      rootElement.innerHTML = '<div class="empty-state-card">这个目录目前没有内容。</div>';
      return;
    }

    if (entries.length === 0) {
      rootElement.innerHTML = '<div class="empty-state-card">没有匹配当前搜索的文件。</div>';
      return;
    }

    if (state.view === 'grid') {
      rootElement.innerHTML = `<div class="explorer-grid">${renderCards(entries)}</div>`;
      return;
    }

    rootElement.innerHTML = `
      <table class="explorer-tbl">
        <thead>
          <tr>
            <th class="explorer-col-chk"></th>
            <th class="explorer-sortable" data-sort="name">名称 ${sortArrow('name')}</th>
            <th class="explorer-col-size explorer-sortable" data-sort="size">大小 ${sortArrow('size')}</th>
            <th class="explorer-col-type explorer-sortable" data-sort="type">类型 ${sortArrow('type')}</th>
            <th class="explorer-col-time explorer-sortable" data-sort="mtime">修改时间 ${sortArrow('mtime')}</th>
          </tr>
        </thead>
        <tbody>${renderRows(entries)}</tbody>
      </table>
    `;
  }

  function emitSelectionChange() {
    onSelectionChange?.(new Set(state.selected), fileEntries().length);
  }

  function toggleSelection(fileId, selected) {
    if (selected) {
      state.selected.add(fileId);
    } else {
      state.selected.delete(fileId);
    }
    render();
    emitSelectionChange();
  }

  // ── 事件委托 ──
  rootElement.addEventListener('click', (event) => {
    const checkbox = event.target.closest('.explorer-row-check');
    if (checkbox instanceof HTMLInputElement) {
      event.stopPropagation();
      toggleSelection(checkbox.dataset.fileId, checkbox.checked);
      return;
    }

    const sortable = event.target.closest('.explorer-sortable');
    if (sortable instanceof HTMLElement) {
      const key = sortable.dataset.sort;
      if (state.sortKey === key) {
        state.sortDir = state.sortDir === 'asc' ? 'desc' : 'asc';
      } else {
        state.sortKey = key;
        state.sortDir = 'asc';
      }
      render();
      return;
    }

    const item = event.target.closest('[data-type]');
    if (!(item instanceof HTMLElement)) {
      return;
    }

    if (item.dataset.type === 'dir') {
      onOpenDir?.(item.dataset.path);
      return;
    }

    const entry = state.entries.find((candidate) => candidate.id === item.dataset.fileId);
    if (entry) {
      state.activeFileId = entry.id;
      render();
      onSelectFile?.(entry);
    }
  });

  rootElement.addEventListener('dblclick', (event) => {
    const item = event.target.closest('[data-type="file"]');
    if (!(item instanceof HTMLElement)) {
      return;
    }
    const entry = state.entries.find((candidate) => candidate.id === item.dataset.fileId);
    if (entry) {
      onOpenFile?.(entry);
    }
  });

  rootElement.addEventListener('contextmenu', (event) => {
    const item = event.target.closest('[data-type]');
    if (!(item instanceof HTMLElement) || !handlers.onContextMenu) {
      return;
    }
    event.preventDefault();
    const entry =
      item.dataset.type === 'file'
        ? state.entries.find((candidate) => candidate.id === item.dataset.fileId)
        : { type: 'dir', path: item.dataset.path };
    handlers.onContextMenu(entry, { x: event.clientX, y: event.clientY });
  });

  return {
    setEntries(entries) {
      state.entries = Array.isArray(entries) ? entries : [];
      state.selected.clear();
      state.activeFileId = null;
      render();
      emitSelectionChange();
    },
    setView(view) {
      state.view = view === 'grid' ? 'grid' : 'list';
      render();
    },
    setSort(key, dir) {
      state.sortKey = key;
      state.sortDir = dir;
      render();
    },
    setFilter(value) {
      state.filter = value ?? '';
      render();
    },
    setActiveFile(fileId) {
      state.activeFileId = fileId;
      render();
    },
    selectAll(selected) {
      if (selected) {
        for (const entry of fileEntries()) {
          state.selected.add(entry.id);
        }
      } else {
        state.selected.clear();
      }
      render();
      emitSelectionChange();
    },
    clearSelection() {
      state.selected.clear();
      state.activeFileId = null;
      render();
      emitSelectionChange();
    },
    getSelectedIds() {
      return [...state.selected];
    },
    getFileCount() {
      return fileEntries().length;
    },
    getEntries() {
      return state.entries.slice();
    }
  };
}