/**
 * Bulk export — export crawled screens to CSV / JSON / Markdown digest.
 *
 * Outputs:
 * - CSV: url, name, wordCount, screenshotPath, markdownPath, createdAt — for spreadsheet analysis
 * - JSON: full screen records array — for API integration
 * - Markdown digest: concatenated markdown of all screens — for LLM context windows
 */

import * as fs from 'fs/promises';
import * as path from 'path';

export interface ExportScreen {
  id: string;
  name: string;
  url: string;
  projectId: string;
  wordCount?: number;
  screenshotPath?: string | null;
  markdownPath?: string | null;
  markdown?: string | null;
  createdAt?: Date;
  updatedAt?: Date;
}

function escapeCsv(val: string): string {
  if (val.includes(',') || val.includes('"') || val.includes('\n')) {
    return `"${val.replace(/"/g, '""')}"`;
  }
  return val;
}

export async function exportToCsv(screens: ExportScreen[], outputPath: string): Promise<void> {
  const headers = ['id', 'name', 'url', 'projectId', 'wordCount', 'screenshotPath', 'markdownPath', 'createdAt'];
  const rows = screens.map(s => [
    s.id, s.name, s.url, s.projectId,
    String(s.wordCount ?? 0),
    s.screenshotPath ?? '',
    s.markdownPath ?? '',
    s.createdAt?.toISOString() ?? '',
  ].map(escapeCsv).join(','));

  await fs.mkdir(path.dirname(outputPath), { recursive: true });
  await fs.writeFile(outputPath, [headers.join(','), ...rows].join('\n'), 'utf8');
}

export async function exportToJson(screens: ExportScreen[], outputPath: string): Promise<void> {
  await fs.mkdir(path.dirname(outputPath), { recursive: true });
  const data = screens.map(s => ({
    id: s.id,
    name: s.name,
    url: s.url,
    projectId: s.projectId,
    wordCount: s.wordCount,
    screenshotPath: s.screenshotPath,
    markdownPath: s.markdownPath,
    createdAt: s.createdAt?.toISOString(),
    updatedAt: s.updatedAt?.toISOString(),
  }));
  await fs.writeFile(outputPath, JSON.stringify(data, null, 2), 'utf8');
}

export async function exportToMarkdownDigest(
  screens: ExportScreen[],
  outputPath: string,
  opts: { readMarkdownFromPath?: boolean; maxScreens?: number } = {},
): Promise<void> {
  const { readMarkdownFromPath = true, maxScreens = 200 } = opts;
  await fs.mkdir(path.dirname(outputPath), { recursive: true });

  const handle = await fs.open(outputPath, 'w');
  try {
    await handle.write(`# ZeTa Crawl Digest\n\nExported: ${new Date().toISOString()}\nScreens: ${Math.min(screens.length, maxScreens)}\n\n---\n\n`);

    for (const screen of screens.slice(0, maxScreens)) {
      let md = screen.markdown ?? '';
      if (!md && readMarkdownFromPath && screen.markdownPath) {
        md = await fs.readFile(screen.markdownPath, 'utf8').catch(() => '');
      }
      await handle.write(`## ${screen.name}\n\n**URL:** ${screen.url}\n\n${md.trim()}\n\n---\n\n`);
    }
  } finally {
    await handle.close();
  }
}