const { appendFile, readFile, readdir, writeFile } = require('node:fs/promises');
const path = require('node:path');

function releaseEnvironment(context) {
  const env = context.env ?? process.env;
  const serverUrl = env.GITEA_URL?.replace(/\/$/, '');
  const repository = env.GITEA_REPOSITORY;
  const token = env.GITEA_TOKEN;

  if (!serverUrl || !repository || !token) {
    throw new Error('GITEA_URL, GITEA_REPOSITORY, and GITEA_TOKEN are required');
  }
  if (!/^https?:\/\//.test(serverUrl)) {
    throw new Error('GITEA_URL must be an HTTP(S) URL');
  }
  if (!/^[^/]+\/[^/]+$/.test(repository)) {
    throw new Error('GITEA_REPOSITORY must use the owner/repository format');
  }

  return { serverUrl, repository, token };
}

async function giteaRequest(url, token, options = {}) {
  const response = await fetch(url, {
    ...options,
    headers: {
      Authorization: `token ${token}`,
      ...options.headers,
    },
  });

  if (!response.ok) {
    const body = (await response.text()).slice(0, 2_000);
    throw new Error(`Gitea API request failed (${response.status} ${response.statusText}): ${body}`);
  }

  return response;
}

module.exports.verifyConditions = async (_pluginConfig, context) => {
  releaseEnvironment(context);
};

module.exports.prepare = async (pluginConfig, context) => {
  const { nextRelease, cwd } = context;
  const notes = nextRelease.notes?.trim();
  if (!notes) return;

  const { serverUrl, repository } = releaseEnvironment(context);
  const changelogPath = path.resolve(cwd, pluginConfig.changelogFile ?? 'CHANGELOG.md');
  const releaseJsonPath = path.resolve(cwd, pluginConfig.releaseJsonPath ?? 'patches-bundle.json');

  let currentChangelog = '';
  try {
    currentChangelog = (await readFile(changelogPath, 'utf8')).trim();
  } catch (error) {
    if (error.code !== 'ENOENT') throw error;
  }

  await writeFile(
    changelogPath,
    `${notes}\n${currentChangelog ? `\n${currentChangelog}\n` : ''}`,
  );

  const version = nextRelease.version;
  const assetName = `patches-${version}.mpp`;
  const releaseData = {
    created_at: new Date().toISOString().replace(/\.\d{3}Z$/, ''),
    description: notes,
    download_url: `${serverUrl}/${repository}/releases/download/${nextRelease.gitTag}/${assetName}`,
    signature_download_url: '',
    version,
  };
  await writeFile(releaseJsonPath, `${JSON.stringify(releaseData, null, 2)}\n`);
};

module.exports.publish = async (pluginConfig, context) => {
  const { serverUrl, repository, token } = releaseEnvironment(context);
  const { branch, cwd, nextRelease } = context;
  const repositoryPath = repository.split('/').map(encodeURIComponent).join('/');
  const apiUrl = `${serverUrl}/api/v1/repos/${repositoryPath}`;

  const assetDirectory = path.resolve(
    cwd,
    pluginConfig.assetDirectory ?? 'patches/build/libs',
  );
  const assetNames = (await readdir(assetDirectory))
    .filter((name) => /\.mpp(?:\.asc)?$/.test(name))
    .filter((name) => !/(?:sources|javadoc)/.test(name))
    .sort();

  if (assetNames.length === 0) {
    throw new Error(`No release assets found in ${assetDirectory}`);
  }
  const releaseResponse = await giteaRequest(`${apiUrl}/releases`, token, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      body: nextRelease.notes,
      draft: false,
      name: nextRelease.name,
      prerelease: Boolean(branch.prerelease),
      tag_name: nextRelease.gitTag,
      target_commitish: branch.name,
    }),
  });
  const release = await releaseResponse.json();

  for (const assetName of assetNames) {
    const contents = await readFile(path.join(assetDirectory, assetName));
    const form = new FormData();
    form.append('attachment', new Blob([contents]), assetName);
    await giteaRequest(
      `${apiUrl}/releases/${release.id}/assets?name=${encodeURIComponent(assetName)}`,
      token,
      { method: 'POST', body: form },
    );
  }

  if (process.env.GITHUB_OUTPUT) {
    await appendFile(
      process.env.GITHUB_OUTPUT,
      `new_release_published=true\nnew_release_git_tag=${nextRelease.gitTag}\n`,
    );
  }

  return { name: release.name, url: release.html_url };
};