import { createFileRoute } from "@tanstack/react-router";
import { zipSync, strToU8 } from "fflate";
import { z } from "zod";

const PostSchema = z.object({
  id: z.string(),
  fileUrl: z.string().url(),
  ext: z.string().default("jpg"),
  previewUrl: z.string().optional(),
  sampleUrl: z.string().optional(),
  tags: z.array(z.string()).default([]),
  source: z.string().optional(),
  rating: z.string().optional(),
  score: z.number().optional(),
  fileSize: z.number().optional(),
  width: z.number().optional(),
  height: z.number().optional(),
  md5: z.string().optional(),
  uploader: z.union([z.string(), z.number()]).optional(),
  createdAt: z.string().optional(),
  rawJson: z.string().optional(),
});

const BodySchema = z.object({
  siteName: z.string().default("grabber"),
  posts: z.array(PostSchema).min(1).max(200),
  excludeTags: z.array(z.string()).default([]),
});

function sanitize(s: string) {
  return s.replace(/[^a-zA-Z0-9._-]+/g, "_").slice(0, 60);
}

function humanSize(n?: number): string {
  if (n == null || !Number.isFinite(n)) return "";
  if (n < 1024) return `${n} B`;
  if (n < 1024 * 1024) return `${(n / 1024).toFixed(1)} KB`;
  if (n < 1024 * 1024 * 1024) return `${(n / 1024 / 1024).toFixed(2)} MB`;
  return `${(n / 1024 / 1024 / 1024).toFixed(2)} GB`;
}

function buildMarkdown(post: z.infer<typeof PostSchema>, excludeSet: Set<string>): string {
  const dims = post.width && post.height ? `${post.width} x ${post.height}` : "";
  const rows: [string, string][] = [
    ["Source", post.source ?? ""],
    ["Rating", post.rating ?? ""],
    ["Score", post.score != null ? String(post.score) : ""],
    ["Dimensions", dims],
    ["File size", humanSize(post.fileSize)],
    ["MD5", post.md5 ?? ""],
    ["Uploader", post.uploader != null ? String(post.uploader) : ""],
    ["Created at", post.createdAt ?? ""],
    ["Original file", post.fileUrl],
    ["Sample", post.sampleUrl ?? ""],
    ["Preview", post.previewUrl ?? ""],
    ["Ext", post.ext],
  ];

  const meta = rows.map(([k, v]) => `- **${k}:** ${v}`).join("\n");
  const filteredTags = post.tags.filter((t) => !excludeSet.has(t.toLowerCase()));
  const tags = filteredTags.length ? filteredTags.join(" ") : "";
  let raw = "{}";
  if (post.rawJson) {
    try {
      raw = JSON.stringify(JSON.parse(post.rawJson), null, 2);
    } catch {
      raw = post.rawJson;
    }
  }

  return `# Post ${post.id}

${meta}

## Tags

${tags}

## Raw metadata

\`\`\`json
${raw}
\`\`\`
`;
}

export const Route = createFileRoute("/api/download-zip")({
  server: {
    handlers: {
      POST: async ({ request }) => {
        let body: z.infer<typeof BodySchema>;
        try {
          body = BodySchema.parse(await request.json());
        } catch (err) {
          return new Response(
            JSON.stringify({ error: err instanceof Error ? err.message : "Invalid body" }),
            { status: 400, headers: { "Content-Type": "application/json" } },
          );
        }

        const files: Record<string, Uint8Array> = {};
        const errors: string[] = [];
        const siteName = sanitize(body.siteName);
        const excludeSet = new Set((body.excludeTags || []).map((t) => t.toLowerCase()));

        await Promise.all(
          body.posts.map(async (post) => {
            const idSafe = sanitize(post.id);
            const extSafe = sanitize(post.ext || "jpg");
            const base = `${siteName}_${idSafe}`;

            // Filter out tags that user specified to be missing
            const filteredTags = post.tags.filter((t) => !excludeSet.has(t.toLowerCase()));

            // tags .txt — same basename as the image
            files[`${base}.txt`] = strToU8(filteredTags.join(" "));

            // per-post markdown metadata
            files[`${idSafe}.md`] = strToU8(buildMarkdown(post, excludeSet));

            // fetch the image itself
            try {
              const res = await fetch(post.fileUrl, {
                headers: { "User-Agent": "LovableGrabber/1.0" },
              });
              if (!res.ok) {
                errors.push(`${post.id}: HTTP ${res.status}`);
                return;
              }
              const buf = new Uint8Array(await res.arrayBuffer());
              files[`${base}.${extSafe}`] = buf;
            } catch (err) {
              errors.push(`${post.id}: ${err instanceof Error ? err.message : "fetch failed"}`);
            }
          }),
        );

        if (errors.length) {
          files["_errors.txt"] = strToU8(errors.join("\n"));
        }

        if (Object.keys(files).length === 0) {
          return new Response(JSON.stringify({ error: "No files downloaded" }), {
            status: 502,
            headers: { "Content-Type": "application/json" },
          });
        }

        const zipped = zipSync(files, { level: 0 });
        const ts = new Date().toISOString().replace(/[:.]/g, "-");
        return new Response(zipped, {
          status: 200,
          headers: {
            "Content-Type": "application/zip",
            "Content-Disposition": `attachment; filename="grabber-${ts}.zip"`,
            "Cache-Control": "no-store",
          },
        });
      },
    },
  },
});