/**
 * stitch-export.ts — Export Stitch designs as HTML, image, or DESIGN.md.
 *
 * Usage:
 *   npx tsx stitch-export.ts <screen-id> [--project <id>] [--format html|image|all] [--output <dir>]
 *
 * Env: STITCH_API_KEY (required), STITCH_PROJECT_ID (optional default)
 */

import { stitch } from "@google/stitch-sdk";
import fs from "fs";
import path from "path";

// -- Argument parsing --

const args = process.argv.slice(2);

function getFlag(name: string): string | undefined {
  const idx = args.indexOf(`--${name}`);
  if (idx === -1 || idx + 1 >= args.length) return undefined;
  return args[idx + 1];
}

// Extract positional args (skip flags and their values)
function getPositionalArgs(): string[] {
  const positional: string[] = [];
  for (let i = 0; i < args.length; i++) {
    if (args[i].startsWith("--")) {
      i++; // skip flag value
    } else {
      positional.push(args[i]);
    }
  }
  return positional;
}

const screenId = getPositionalArgs()[0];
const projectId =
  getFlag("project") || process.env.STITCH_PROJECT_ID || "claudekit-default";
const format = getFlag("format") || "all";
const outputDir = getFlag("output") || "./stitch-exports";

if (!screenId) {
  console.error("Usage: npx tsx stitch-export.ts <screen-id> [--project <id>] [--format html|image|all] [--output <dir>]");
  process.exit(1);
}

if (!process.env.STITCH_API_KEY) {
  console.error("[X] STITCH_API_KEY not set. Get one at https://stitch.withgoogle.com/settings/api");
  process.exit(1);
}

// -- Helpers --

async function downloadFile(url: string, dest: string): Promise<void> {
  const response = await fetch(url);
  if (!response.ok) throw new Error(`Download failed: ${response.status} ${response.statusText}`);
  const buffer = Buffer.from(await response.arrayBuffer());
  fs.writeFileSync(dest, buffer);
}

/**
 * Generate a DESIGN.md from HTML content by extracting Tailwind classes,
 * color values, typography patterns, and component structure.
 */
function generateDesignMd(html: string): string {
  const lines: string[] = ["# Design System", "", "Auto-generated from Google Stitch export.", ""];

  // Extract colors from Tailwind classes and inline styles
  const colorMatches = html.match(/(?:bg|text|border)-(?:\w+)-(\d+)/g) || [];
  const uniqueColors = [...new Set(colorMatches)].slice(0, 20);
  if (uniqueColors.length > 0) {
    lines.push("## Colors", "");
    uniqueColors.forEach((c) => lines.push(`- \`${c}\``));
    lines.push("");
  }

  // Extract typography classes
  const textMatches = html.match(/(?:text-(?:xs|sm|base|lg|xl|2xl|3xl|4xl|5xl)|font-(?:thin|light|normal|medium|semibold|bold|extrabold))/g) || [];
  const uniqueText = [...new Set(textMatches)].slice(0, 15);
  if (uniqueText.length > 0) {
    lines.push("## Typography", "");
    uniqueText.forEach((t) => lines.push(`- \`${t}\``));
    lines.push("");
  }

  // Extract spacing patterns
  const spacingMatches = html.match(/(?:p|m|gap|space)-(?:x|y)?-?\d+/g) || [];
  const uniqueSpacing = [...new Set(spacingMatches)].slice(0, 15);
  if (uniqueSpacing.length > 0) {
    lines.push("## Spacing", "");
    uniqueSpacing.forEach((s) => lines.push(`- \`${s}\``));
    lines.push("");
  }

  // Extract component-level structure from HTML tags
  const componentMatches = html.match(/<(section|nav|header|footer|main|aside|form|button|input|table|dialog)[^>]*>/gi) || [];
  const uniqueComponents = [...new Set(componentMatches.map((c) => c.match(/<(\w+)/)?.[1] || ""))].filter(Boolean);
  if (uniqueComponents.length > 0) {
    lines.push("## Components", "");
    uniqueComponents.forEach((c) => lines.push(`- \`<${c}>\``));
    lines.push("");
  }

  lines.push("## Notes", "", "- Generated by Google Stitch AI", "- Tailwind CSS utility classes used throughout", "- Review and customize colors/typography for brand alignment");

  return lines.join("\n");
}

// -- Main --

async function main() {
  try {
    fs.mkdirSync(outputDir, { recursive: true });

    console.error(`[i] Exporting screen ${screenId} from project ${projectId}`);
    // Resolve project handle — for default project, find by title first
    let project;
    if (projectId === "claudekit-default") {
      const projects = await stitch.projects();
      const found = projects.find(p => p.data?.title === "claudekit-default");
      project = found || stitch.project(projectId);
    } else {
      project = stitch.project(projectId);
    }
    const screen = await project.getScreen(screenId!);

    const exported: Record<string, string> = {};

    // Export HTML
    if (format === "html" || format === "all") {
      const htmlUrl = await screen.getHtml();
      const htmlPath = path.join(outputDir, "design.html");
      await downloadFile(htmlUrl, htmlPath);
      exported.html = htmlPath;
      console.error(`[OK] HTML exported: ${htmlPath}`);

      // Generate DESIGN.md from HTML
      if (format === "all") {
        const htmlContent = fs.readFileSync(htmlPath, "utf-8");
        const designMd = generateDesignMd(htmlContent);
        const designPath = path.join(outputDir, "DESIGN.md");
        fs.writeFileSync(designPath, designMd);
        exported.designMd = designPath;
        console.error(`[OK] DESIGN.md generated: ${designPath}`);
      }
    }

    // Export image
    if (format === "image" || format === "all") {
      const imageUrl = await screen.getImage();
      const imagePath = path.join(outputDir, "design.png");
      await downloadFile(imageUrl, imagePath);
      exported.image = imagePath;
      console.error(`[OK] Image exported: ${imagePath}`);
    }

    // Output result JSON to stdout
    console.log(JSON.stringify({ screenId, projectId, format, exported }, null, 2));
  } catch (error: unknown) {
    const err = error as { code?: string; message?: string };
    if (err.code === "NOT_FOUND") {
      console.error(`[X] Screen "${screenId}" not found in project "${projectId}".`);
    } else if (err.code === "AUTH_FAILED") {
      console.error("[X] Authentication failed. Check STITCH_API_KEY env var.");
    } else {
      console.error(`[X] Export error: ${err.message || error}`);
    }
    process.exit(1);
  }
}

main();