import sharp from "sharp";
import path from "path";
import { mkdirSync } from "fs";
import { runAgentStep } from "./claude";

const PIPELINE_ROOT = process.env.PIPELINE_ROOT || path.join(process.cwd(), "pipeline");

const PLATFORM_FORMATS: Record<string, { width: number; height: number; label: string }> = {
  "instagram-feed": { width: 1080, height: 1080, label: "Instagram Feed" },
  "instagram-stories": { width: 1080, height: 1920, label: "Instagram Stories" },
  tiktok: { width: 1080, height: 1920, label: "TikTok" },
  "nextdoor-spotlight": { width: 1200, height: 1200, label: "Nextdoor Spotlight" },
  "nextdoor-display": { width: 1200, height: 628, label: "Nextdoor Display" },
};

export function getAvailableFormats(currentDimensions: string | null): string[] {
  return Object.keys(PLATFORM_FORMATS).filter((key) => {
    const fmt = PLATFORM_FORMATS[key];
    return `${fmt.width}x${fmt.height}` !== currentDimensions;
  });
}

export function getPlatformFormat(key: string) {
  return PLATFORM_FORMATS[key] || null;
}

/**
 * Resize an image to target platform dimensions using Sharp.
 * Uses cover fit + center crop for aspect ratio changes.
 */
export async function resizeImage(
  sourcePath: string,
  targetFormat: string,
  outputDir: string
): Promise<{ filePath: string; fileName: string; dimensions: string; platform: string }> {
  const fmt = PLATFORM_FORMATS[targetFormat];
  if (!fmt) throw new Error(`Unknown format: ${targetFormat}`);

  mkdirSync(path.join(PIPELINE_ROOT, outputDir), { recursive: true });

  const sourceBase = path.basename(sourcePath, path.extname(sourcePath));
  const fileName = `${sourceBase}_${targetFormat}_${fmt.width}x${fmt.height}.png`;
  const outputPath = path.join(outputDir, fileName);
  const fullOutputPath = path.join(PIPELINE_ROOT, outputPath);
  const fullSourcePath = path.join(PIPELINE_ROOT, sourcePath);

  await sharp(fullSourcePath)
    .resize(fmt.width, fmt.height, { fit: "cover", position: "centre" })
    .png()
    .toFile(fullOutputPath);

  const platform = targetFormat.split("-")[0];

  return { filePath: outputPath, fileName, dimensions: `${fmt.width}x${fmt.height}`, platform };
}

/**
 * Re-tone a caption for a different platform using Claude CLI.
 */
export async function retoneCaption(
  originalCaption: string,
  originalPlatform: string,
  targetPlatform: string
): Promise<string> {
  const prompt = `You are a social media copywriter. Adapt this ${originalPlatform} caption for ${targetPlatform}.

Original caption:
${originalCaption}

Rules:
- ${targetPlatform === "tiktok" ? "Raw, authentic tone. Short. Trending hashtags. Hook in first line." : ""}
- ${targetPlatform === "instagram" ? "Polished, aspirational. Hook → Value → CTA → Hashtags. 150-300 chars." : ""}
- ${targetPlatform === "nextdoor" ? "Warm, neighborly. No hashtags. Reference local/community context." : ""}
- Keep the core message but match the platform's voice.
- Return ONLY the new caption text, nothing else.`;

  const { output } = await runAgentStep("caption-retone", prompt, PIPELINE_ROOT, {});
  return output.trim();
}

/**
 * Repurpose an image asset to specific platform formats.
 */
export async function repurposeImage(
  sourcePath: string,
  targetFormats: string[],
  outputDir: string
): Promise<Array<{ filePath: string; fileName: string; dimensions: string; platform: string }>> {
  const results = [];
  for (const fmt of targetFormats) {
    const result = await resizeImage(sourcePath, fmt, outputDir);
    results.push(result);
  }
  return results;
}