import { env } from "cloudflare:workers";
import { all, first } from "./db";
import { branchSha, listRefs } from "./git/refs";
import { withStore } from "./git/store";
import { renderMarkdown } from "./markdown";
import { REPO_SELECT } from "./repos";
import type { RepoRow } from "~/lib/types";

const DAY_MS = 24 * 60 * 60 * 1000;
const GRAPH_WEEKS = 52;
const WEEK_DAYS = 7;
const README_NAMES = new Set(["readme.md", "readme.markdown"]);
const MAX_README_BYTES = 256 * 1024;
const README_CACHE_TTL_SECONDS = 60 * 60 * 24 * 7;
const decoder = new TextDecoder();

export type ContributionBreakdown = { commits: number; pulls: number; issues: number; reviews: number; other: number };

export type ContributionDay = {
  date: string;
  count: number;
  breakdown: ContributionBreakdown | null;
  repos: string[];
};

const MAX_DAY_REPOS = 3;

type Category = keyof ContributionBreakdown;

function categoryOf(kind: string): Category {
  if (kind === "push" || kind === "ref_created") return "commits";
  if (kind.startsWith("pull_")) return "pulls";
  if (kind.startsWith("issue_")) return "issues";
  if (kind === "comment" || kind.startsWith("review")) return "reviews";
  return "other";
}

/** Daily repository activity counts (public repos unless `includePrivate`) for roughly the last year, oldest first, aligned to whole weeks, with a per-day breakdown for hover cards. */
export async function contributionGraph(accountId: string, includePrivate: boolean): Promise<ContributionDay[]> {
  const now = Date.now();
  const today = new Date(now);
  const midnight = Date.UTC(today.getUTCFullYear(), today.getUTCMonth(), today.getUTCDate());
  const start = new Date(midnight - (GRAPH_WEEKS * WEEK_DAYS + today.getUTCDay()) * DAY_MS);
  const rows = await all<{ day: string; kind: string; repo: string; events: number; commits: number | null }>(
    `SELECT strftime('%Y-%m-%d', ac.created_at / 1000, 'unixepoch') AS day, ac.kind, a.name || '/' || r.name AS repo,
       COUNT(*) AS events,
       SUM(CASE WHEN ac.kind = 'push' THEN COALESCE(json_extract(ac.data, '$.total'), 1) ELSE 0 END) AS commits
     FROM activity ac JOIN repos r ON r.id = ac.repo_id JOIN accounts a ON a.id = r.owner_id
     WHERE ac.actor_id = ? AND ac.created_at >= ? AND ac.kind != 'view' AND (? = 1 OR r.visibility = 'public')
     GROUP BY day, ac.kind, repo`,
    accountId,
    start.getTime(),
    includePrivate ? 1 : 0,
  );
  const byDay = new Map<string, { count: number; breakdown: ContributionBreakdown; repoEvents: Map<string, number> }>();
  for (const row of rows) {
    const entry = byDay.get(row.day) ?? {
      count: 0,
      breakdown: { commits: 0, pulls: 0, issues: 0, reviews: 0, other: 0 },
      repoEvents: new Map<string, number>(),
    };
    const category = categoryOf(row.kind);
    entry.count += row.events;
    entry.breakdown[category] +=
      category === "commits" && row.kind === "push" ? (row.commits ?? row.events) : row.events;
    entry.repoEvents.set(row.repo, (entry.repoEvents.get(row.repo) ?? 0) + row.events);
    byDay.set(row.day, entry);
  }
  const days: ContributionDay[] = [];
  for (let time = start.getTime(); time <= now; time += DAY_MS) {
    const date = new Date(time).toISOString().slice(0, 10);
    const entry = byDay.get(date);
    days.push({
      date,
      count: entry?.count ?? 0,
      breakdown: entry?.breakdown ?? null,
      repos: entry
        ? [...entry.repoEvents.entries()]
            .sort((left, right) => right[1] - left[1])
            .slice(0, MAX_DAY_REPOS)
            .map(([name]) => name)
        : [],
    });
  }
  return days;
}

/** Renders README.md from the public `<name>/<name>` repo, cached in KV by commit. */
export async function profileReadme(accountName: string): Promise<string | null> {
  const repo = await first<RepoRow>(
    `${REPO_SELECT} WHERE a.name = ?1 AND r.name = ?1 AND r.visibility = 'public' AND r.status = 'ready'`,
    accountName,
  );
  if (!repo) return null;
  const refs = await listRefs(repo);
  const sha = branchSha(refs, repo.default_branch);
  if (!sha) return null;
  const cacheKey = `profile-readme:${repo.id}:${sha}`;
  const cached = await env.KV.get(cacheKey);
  if (cached !== null) return cached || null;
  const html = await withStore(repo.artifacts_name, async (store) => {
    const commit = await store.commit(sha);
    if (!commit) return "";
    const entries = await store.listTree(commit.treeSha, "");
    const entry = entries.find(
      (candidate) => candidate.type !== "tree" && README_NAMES.has(candidate.name.toLowerCase()),
    );
    if (!entry) return "";
    const bytes = await store.blob(entry.sha);
    if (!bytes || bytes.byteLength > MAX_README_BYTES) return "";
    return renderMarkdown(decoder.decode(bytes), {
      owner: repo.owner_name,
      repo: repo.name,
      ref: repo.default_branch,
      basePath: "",
    });
  });
  await env.KV.put(cacheKey, html, { expirationTtl: README_CACHE_TTL_SECONDS });
  return html || null;
}