import { NextResponse } from "next/server";
import { boardConfig } from "../../../board.config";

type GithubContent = {
  name: string;
  path: string;
  type: "file" | "dir";
  download_url: string | null;
  html_url: string;
};

type ShamePhoto = {
  name: string;
  path: string;
  url: string;
  htmlUrl: string;
};

const imageExtensionPattern = /\.(avif|gif|jpe?g|png|webp)$/i;

function parseRepo(value: string | null) {
  const clean = value?.trim().replace(/^https:\/\/github\.com\//, "") ?? "";
  const [owner, repo] = clean.split("/");

  if (!owner || !repo) {
    return null;
  }

  return {
    owner,
    repo: repo.replace(/\.git$/, "")
  };
}

async function fetchDirectory(owner: string, repo: string, path: string, branch?: string) {
  const encodedPath = path
    .split("/")
    .filter(Boolean)
    .map((part) => encodeURIComponent(part))
    .join("/");
  const url = new URL(`https://api.github.com/repos/${owner}/${repo}/contents/${encodedPath}`);

  if (branch) {
    url.searchParams.set("ref", branch);
  }

  const response = await fetch(url, {
    headers: {
      Accept: "application/vnd.github+json",
      "X-GitHub-Api-Version": "2022-11-28"
    },
    next: { revalidate: 60 }
  });

  if (!response.ok) {
    return {
      ok: false as const,
      status: response.status,
      message: response.status === 404 ? "Repository or folder was not found." : "GitHub did not return the photo list."
    };
  }

  const content = (await response.json()) as GithubContent[] | GithubContent;
  const items = Array.isArray(content) ? content : [content];

  return {
    ok: true as const,
    items
  };
}

export async function GET() {
  const branch = boardConfig.branch || undefined;
  const path = boardConfig.photosPath;
  const parsedRepo = parseRepo(boardConfig.repo);

  if (!parsedRepo) {
    return NextResponse.json({
      photos: [],
      repo: null,
      path,
      message: "Set a GitHub repository to load the board."
    });
  }

  const directory = await fetchDirectory(parsedRepo.owner, parsedRepo.repo, path, branch);

  if (!directory.ok) {
    return NextResponse.json(
      {
        photos: [],
        repo: `${parsedRepo.owner}/${parsedRepo.repo}`,
        path,
        message: directory.message
      },
      { status: directory.status }
    );
  }

  const photos: ShamePhoto[] = directory.items
    .filter((item) => item.type === "file" && item.download_url && imageExtensionPattern.test(item.name))
    .map((item) => ({
      name: item.name.replace(imageExtensionPattern, ""),
      path: item.path,
      url: item.download_url as string,
      htmlUrl: item.html_url
    }));

  return NextResponse.json({
    photos,
    repo: `${parsedRepo.owner}/${parsedRepo.repo}`,
    path,
    branch: branch ?? null,
    message: photos.length ? null : "No image files were found in that GitHub folder."
  });
}