/**
 * @param {{ github: ReturnType<typeof import('@actions/github').getOctokit>, context: typeof import('@actions/github').context, core: typeof import('@actions/core') }} githubScript
 * @returns {Promise<void>}
 */
export default async function checkPr({ github, context, core }) {
    const author = context.payload.pull_request.user.login;
    const prNumber = context.payload.pull_request.number;

    // Skip bots
    if (author.endsWith('[bot]')) {
        core.info(`Skipping bot: ${author}`);
        return;
    }

    // Read the VOUCHED.td file via API (no checkout needed)
    let content;
    try {
        const response = await github.rest.repos.getContent({
            owner: context.repo.owner,
            repo: context.repo.repo,
            path: '.github/VOUCHED.td',
        });
        content = Buffer.from(response.data.content, 'base64').toString('utf-8');
    } catch (error) {
        if (error.status === 404) {
            core.info('No .github/VOUCHED.td file found, skipping check.');
            return;
        }
        throw error;
    }

    // Parse the .td file for vouched and denounced users
    const vouched = new Set();
    const denounced = new Map();
    for (const line of content.split('\n')) {
        const trimmed = line.trim();
        if (!trimmed || trimmed.startsWith('#')) {
            continue;
        }

        const isDenounced = trimmed.startsWith('-');
        const rest = isDenounced ? trimmed.slice(1).trim() : trimmed;
        if (!rest) {
            continue;
        }

        const spaceIdx = rest.indexOf(' ');
        const handle = spaceIdx === -1 ? rest : rest.slice(0, spaceIdx);
        const reason = spaceIdx === -1 ? null : rest.slice(spaceIdx + 1).trim();

        // Handle platform:username or bare username
        // Only match bare usernames or github: prefix (skip other platforms)
        const colonIdx = handle.indexOf(':');
        if (colonIdx !== -1) {
            const platform = handle.slice(0, colonIdx).toLowerCase();
            if (platform !== 'github') {
                continue;
            }
        }
        const username = colonIdx === -1 ? handle : handle.slice(colonIdx + 1);
        if (!username) {
            continue;
        }

        if (isDenounced) {
            denounced.set(username.toLowerCase(), reason);
            continue;
        }

        vouched.add(username.toLowerCase());
    }

    // Check if the author is denounced
    const reason = denounced.get(author.toLowerCase());
    if (reason !== undefined) {
        // Author is denounced — close the PR
        await github.rest.issues.createComment({
            owner: context.repo.owner,
            repo: context.repo.repo,
            issue_number: prNumber,
            body: 'This pull request has been automatically closed.',
        });

        await github.rest.pulls.update({
            owner: context.repo.owner,
            repo: context.repo.repo,
            pull_number: prNumber,
            state: 'closed',
        });

        core.info(`Closed PR #${prNumber} from denounced user ${author}`);
        return;
    }

    // Author is positively vouched — add label
    if (!vouched.has(author.toLowerCase())) {
        core.info(`User ${author} is not denounced or vouched. Allowing PR.`);
        return;
    }

    const association = context.payload.pull_request.author_association;
    if (association === 'OWNER' || association === 'MEMBER' || association === 'COLLABORATOR') {
        core.info(`Skipping vouched label for collaborator ${author} (${association}).`);
        return;
    }

    await github.rest.issues.addLabels({
        owner: context.repo.owner,
        repo: context.repo.repo,
        issue_number: prNumber,
        labels: ['vouched'],
    });

    core.info(`Added vouched label to PR #${prNumber} from ${author}`);
}