// Wire types mirror the moments-entities types serialised by the API.
// Hand-maintained for now; if drift becomes a problem, generate them
// from the Rust crate via ts-rs or specta.

export type Source = 'github' | 'gitea' | 'hg' | 'bugzilla';

export type TitleSegment =
  | { kind: 'text'; text: string }
  | { kind: 'link'; text: string; url: string };

export interface CommitSummary {
  sha: string;
  short_sha: string;
  message: string;
  url: string;
  author: string | null;
}

export type TimelineBody =
  | { kind: 'markdown'; text: string }
  | { kind: 'commits'; commits: CommitSummary[] }
  | { kind: 'links'; items: TitleSegment[] };

export type TimelineIcon =
  | 'git-push'
  | 'git-commit'
  | 'git-merge'
  | 'git-fork'
  | 'git-branch-create'
  | 'git-branch-delete'
  | 'pull-request'
  | 'issue'
  | 'comment'
  | 'star'
  | 'release'
  | 'bug'
  | 'generic';

export interface TimelineItem {
  id: string;
  source: Source;
  action: string;
  occurred_at: string;
  icon: TimelineIcon;
  title: TitleSegment[];
  subtitle: TitleSegment[] | null;
  body: TimelineBody | null;
}

export interface SourceSummary {
  source: Source;
  count: number;
  earliest: string | null;
  latest: string | null;
}

export interface ProjectSummary {
  repo: string;
  source: Source;
  host: string;
  commit_count: number;
  issue_count: number;
  pr_count: number;
  first_activity: string | null;
  last_activity: string | null;
}

export interface DailyCount {
  date: string;
  count: number;
}

export interface EventQuery {
  from?: Date;
  to?: Date;
  sources?: Source[];
  repo?: string;
  limit?: number;
}

const API_BASE = '/api/v1';

/** Decode base64 content as UTF-8 (atob only handles Latin-1). */
function decodeBase64Utf8(b64: string): string {
  const bytes = Uint8Array.from(atob(b64), (c) => c.charCodeAt(0));
  return new TextDecoder().decode(bytes);
}

export async function fetchEvents(q: EventQuery): Promise<TimelineItem[]> {
  const params = new URLSearchParams();
  if (q.from) params.set('from', q.from.toISOString());
  if (q.to) params.set('to', q.to.toISOString());
  if (q.sources && q.sources.length > 0) {
    params.set('source', q.sources.join(','));
  }
  if (q.repo) params.set('repo', q.repo);
  if (q.limit) params.set('limit', String(q.limit));

  const resp = await fetch(`${API_BASE}/events?${params}`);
  if (!resp.ok) throw new Error(`events: HTTP ${resp.status}`);
  return resp.json();
}

export async function fetchSources(): Promise<SourceSummary[]> {
  const resp = await fetch(`${API_BASE}/sources`);
  if (!resp.ok) throw new Error(`sources: HTTP ${resp.status}`);
  return resp.json();
}

export async function fetchDailyCounts(from: string, to: string): Promise<DailyCount[]> {
  const resp = await fetch(`${API_BASE}/activity/daily?from=${from}&to=${to}`);
  if (!resp.ok) throw new Error(`daily-counts: HTTP ${resp.status}`);
  return resp.json();
}

export async function fetchProjects(): Promise<ProjectSummary[]> {
  const resp = await fetch(`${API_BASE}/projects`);
  if (!resp.ok) throw new Error(`projects: HTTP ${resp.status}`);
  return resp.json();
}

/** Fetch repo README as raw markdown via the forge proxy. */
export async function fetchReadme(source: Source, host: string, repo: string): Promise<string | null> {
  if (source === 'github') {
    const resp = await fetch(`${API_BASE}/forge/github/repos/${repo}/readme`);
    if (!resp.ok) return null;
    const data = await resp.json();
    if (data.encoding === 'base64' && data.content) {
      return decodeBase64Utf8(data.content);
    }
    return data.content ?? null;
  }
  if (source === 'gitea') {
    for (const name of ['README.md', 'readme.md', 'Readme.md']) {
      const resp = await fetch(`${API_BASE}/forge/gitea/repos/${repo}/contents/${name}?host=${encodeURIComponent(host)}`);
      if (!resp.ok) continue;
      const data = await resp.json();
      if (data.encoding === 'base64' && data.content) {
        return decodeBase64Utf8(data.content);
      }
      if (data.content) return data.content;
    }
    return null;
  }
  return null;
}

/** Fetch repo languages as { language: bytes } map via the forge proxy. */
export async function fetchLanguages(source: Source, host: string, repo: string): Promise<Record<string, number> | null> {
  if (source !== 'github' && source !== 'gitea') return null;
  const hostParam = source === 'gitea' ? `?host=${encodeURIComponent(host)}` : '';
  const resp = await fetch(`${API_BASE}/forge/${source}/repos/${repo}/languages${hostParam}`);
  if (!resp.ok) return null;
  return resp.json();
}