// gitea's events. The tool runtime imports this once the broker is bound. It watches the forge and
// emits what appeared.
//
// Emits (novox/hq ADR 0041/0042):
//   module.gitea.repo.created   — a repository appeared, however it was made (push, web UI, or tool)
//   module.gitea.pull.merged    — a pull request was merged, however it was merged (web UI, API, or tool)
//   module.gitea.pull.updated   — an open pull request's head moved, opened or pushed to: the mesh checks it
//                                  before it merges (novox/hq to-be 45 §9)
//
//   module.gitea.pull.closed    — a pull request closed unmerged: the delivery it was is stopped (novox/hq ADR 0239)
//
// Consumes mesh-controller.checked — a pull request's merge check, judged — and sets it as the head
// commit's statuses: `mesh/merge-gate`, the modules of the mesh's graph the change touches, and
// `mesh/repo-check`, the repository's own merge-check.sh (novox/hq ADR 0237 as amended); with a comment
// saying why when the gate is not a pass or the repository's own check failed.
//
// Every pull request the forge holds is announced, whatever its repository: the controller holds the
// module graph and decides what is checked — a repository is never asked to opt in.
//
// issue.opened is emitted from its tool (tools/index.ts). repo.created and pull.merged belong here: a
// repository or a merge is as often made by the web UI or a plain API call, which no tool sees, so
// polling is the only way to catch every path — and the only emitter, so a fact is never announced
// twice. The merge tool announced too until novox/hq issue 250, and every merge it made was heard twice.
//
// The polling is deliberately unhurried: an event a minute late is still an event, whereas hammering
// the forge for an immediacy nobody asked for is not.

import { emit, on } from "@novox/mesh-sdk/events";
import { GiteaClient, movedSince } from "./client.js";
import { CHECK_CONTEXT, REPO_CHECK_CONTEXT, commentFor, headsToAnnounce, statusesFor, type Announced, type Checked,
  type RepoCheckFacts } from "./pulls.js";

// Without a way to a token — configured, or mintable with the admin account (token.ts) — there is
// nothing to watch; log and stay quiet rather than crash the runtime. With one, the first poll mints
// or reuses the token, so the runtime's start also shows what it did about it.
let gitea: GiteaClient | null = null;
try {
  gitea = GiteaClient.fromEnv();
} catch (err) {
  console.log(`[gitea] not watching — ${err instanceof Error ? err.message : String(err)}`);
}

// New repositories, by diffing the repo list. Primed silently on the first look, or a restart would
// re-announce every existing repository as freshly created.
const seen = new Set<string>();
let primed = false;
async function pollRepos(client: GiteaClient): Promise<void> {
  const repos = await client.listAllRepos();
  for (const repo of repos) {
    if (!seen.has(repo.full_name)) {
      if (primed) {
        await emit("repo.created", {
          full_name: repo.full_name,
          owner: repo.owner,
          name: repo.name,
          private: repo.private,
          html_url: repo.html_url,
        });
      }
      seen.add(repo.full_name);
    }
  }
  primed = true;
}

// **A merge is announced whoever made it.** The merge tool below emits at the instant it acts; a
// merge made in the forge's own pages or over its API would emit nothing, and the mesh would go on
// believing every module current with its source (novox/hq 04-ISSUES/131). So merged pull requests
// are watched the way repositories are: what the forge holds, asked for on a tick, announced once.
// What has been announced is kept beside the module's state, so a restart does not announce the
// whole history again — and the first tick on a machine with no record announces nothing, because
// everything it sees then predates the watching.
import { existsSync, mkdirSync, readFileSync, renameSync, writeFileSync } from "node:fs";
import { join } from "node:path";
const mergedRecord = process.env.MESH_GITEA_STATE_DIR ? join(process.env.MESH_GITEA_STATE_DIR, "merged-announced.json") : null;
const announced = new Set<string>();
let primedMerges = false;
// since is the moment the watching began: a merge made before it is history, whatever page of the
// forge's listing it surfaces on. Without it, an old merge past the first page — pushed into view
// as newer pull requests were updated — was announced as if it had just happened, and the mesh
// rebuilt everything built from that repository, once per old merge (2026-09-28).
let since = "";
if (mergedRecord && existsSync(mergedRecord)) {
  try {
    const kept = JSON.parse(readFileSync(mergedRecord, "utf8")) as string[] | { announced: string[]; since: string };
    const list = Array.isArray(kept) ? kept : kept.announced;
    for (const sha of list) announced.add(sha);
    since = Array.isArray(kept) ? new Date().toISOString() : kept.since;
    primedMerges = true;
  } catch {
    // An unreadable record is treated as no record: prime again rather than re-announce history.
  }
}
function keepAnnounced(): void {
  if (!mergedRecord) return;
  mkdirSync(join(mergedRecord, ".."), { recursive: true });
  const tmp = mergedRecord + ".tmp";
  writeFileSync(tmp, JSON.stringify({ announced: [...announced].slice(-2000), since }));
  renameSync(tmp, mergedRecord);
}
// **Only the repositories that moved** (novox/hq issue 250). A merge is a push, and a push moves the
// repository's update time; asking every repository for its pull requests on every tick took longer than the
// tick itself, so ticks piled up and a merge was announced minutes late. A repository unchanged since a
// minute before the last look is skipped — the minute absorbs the forge's clock against this one.
let lastLook = "";
const MARGIN_MS = 60_000;
async function pollMerged(client: GiteaClient): Promise<void> {
  const began = new Date().toISOString();
  const floor = lastLook && primedMerges ? new Date(Date.parse(lastLook) - MARGIN_MS).toISOString() : "";
  const repos = movedSince(await client.listAllRepos(), floor);
  let changed = false;
  for (const repo of repos) {
    const pulls = await client.listPullRequests(repo.owner, repo.name, { state: "closed", sort: "recentupdate", limit: "20" });
    for (const pull of pulls) {
      // Closed unmerged (novox/hq ADR 0239): announced once, since the watching began, so its delivery stops.
      const closedKey = `closed:${repo.full_name}#${pull.number}`;
      if (!pull.merged && pull.state === "closed" && !announced.has(closedKey)) {
        if (primedMerges && !!pull.updated_at && !!since && pull.updated_at > since) {
          await emit("pull.closed", { owner: repo.owner, repo: repo.name, number: pull.number, title: pull.title,
            head: pull.head, head_sha: pull.head_sha, base: pull.base, html_url: pull.html_url });
          console.log(`[gitea] announced ${repo.full_name}#${pull.number} closed unmerged`);
        }
        announced.add(closedKey);
        changed = true;
        continue;
      }
      if (!pull.merged || !pull.merge_commit_sha || announced.has(pull.merge_commit_sha)) continue;
      // Announced only if merged since the watching began; recorded either way, so it is looked
      // at once.
      const fresh = !!pull.merged_at && !!since && pull.merged_at > since;
      if (primedMerges && fresh) {
        // What it changed, asked for only now: a module is rebuilt because a file inside its own
        // directory moved, and without this every module built from a repository is rebuilt for a
        // change to any of them (novox/hq 04-ISSUES/131).
        const changed = await client.listPullFiles(repo.owner, repo.name, pull.number);
        // Which of the directories they are in hold a module at the merge commit (novox/hq issue 278): a
        // change inside one is that module's, held or not, and only a file in none is shared code. Not
        // said when the list is cut or the forge could not be asked; the mesh then keeps its old rule.
        let moduleDirs: string[] | null = null;
        if (!changed.truncated) {
          try {
            moduleDirs = await client.moduleDirsAt(repo.owner, repo.name, pull.merge_commit_sha, changed.paths);
          } catch (err) {
            console.error(`[gitea] ${repo.full_name}#${pull.number}: which directories hold a module could not be read, ` +
              `so the mesh reads its files by the old rule — ${err instanceof Error ? err.message : String(err)}`);
          }
        }
        // The head it merged, and what its head was checked as (novox/hq ADR 0239): the delivery it was, made
        // from the forge's word when its owner never heard the head.
        let headChecks: Record<string, string> | null = null;
        if (pull.head_sha) {
          try {
            headChecks = await client.commitStatuses(repo.owner, repo.name, pull.head_sha);
          } catch (err) {
            console.error(`[gitea] ${repo.full_name}#${pull.number}: its head's statuses could not be read — ${err instanceof Error ? err.message : err}`);
          }
        }
        await emit("pull.merged", {
          owner: repo.owner,
          repo: repo.name,
          number: pull.number,
          title: pull.title,
          body: pull.body,
          head_sha: pull.head_sha,
          ...(headChecks ? { head_checks: headChecks } : {}),
          head: pull.head,
          base: pull.base,
          merge_commit_sha: pull.merge_commit_sha,
          merged_at: pull.merged_at,
          clone_url: repo.clone_url,
          html_url: pull.html_url,
          paths: changed.paths,
          paths_truncated: changed.truncated,
          // Which of them the merge deleted (novox/hq ADR 0236): a module whose manifest went is forgotten,
          // not built.
          removed: changed.removed,
          ...(moduleDirs ? { module_dirs: moduleDirs, module_dirs_said: true } : {}),
        });
        // Said, because a trigger that fires silently is indistinguishable from one that did not
        // fire (novox/hq 04-ISSUES/131) — this line is how an operator knows the mesh was told.
        console.log(`[gitea] announced merge ${repo.full_name}#${pull.number} (${pull.merge_commit_sha.slice(0, 8)}) into ${pull.base}`);
      }
      announced.add(pull.merge_commit_sha);
      changed = true;
    }
  }
  if (!primedMerges) since = new Date().toISOString();
  if (!primedMerges || changed) keepAnnounced();
  primedMerges = true;
  lastLook = began;
}

// **Every new head of an open pull request is announced, once** (novox/hq to-be 45 §9): the mesh checks it
// against every machine of its facts before it merges. Kept beside the merges' record, so a restart
// announces nothing twice; the first look on a machine with no record announces only what moved in the
// last day, so a forge's whole backlog is not checked at once.
const pullsRecord = process.env.MESH_GITEA_STATE_DIR ? join(process.env.MESH_GITEA_STATE_DIR, "pulls-announced.json") : null;
let heads: Announced = {};
let primedPulls = false;
if (pullsRecord && existsSync(pullsRecord)) {
  try {
    heads = (JSON.parse(readFileSync(pullsRecord, "utf8")) as { heads: Announced }).heads ?? {};
    primedPulls = true;
  } catch {
    // An unreadable record is no record: the first look announces only the last day's.
  }
}
function keepHeads(): void {
  if (!pullsRecord) return;
  mkdirSync(join(pullsRecord, ".."), { recursive: true });
  const tmp = pullsRecord + ".tmp";
  writeFileSync(tmp, JSON.stringify({ heads }));
  renameSync(tmp, pullsRecord);
}
let lastPullLook = "";
async function pollPulls(client: GiteaClient): Promise<void> {
  const began = new Date().toISOString();
  const floor = lastPullLook ? new Date(Date.parse(lastPullLook) - MARGIN_MS).toISOString() : "";
  const dayAgo = new Date(Date.now() - 24 * 3600_000).toISOString();
  let changed = false;
  for (const repo of movedSince(await client.listAllRepos(), floor)) {
    const open = await client.listPullRequests(repo.owner, repo.name, { state: "open", sort: "recentupdate", limit: "20" });
    for (const pull of headsToAnnounce(repo.full_name, open, heads)) {
      const key = `${repo.full_name}#${pull.number}`;
      const fresh = primedPulls || (!!pull.updated_at && pull.updated_at > dayAgo);
      if (fresh) {
        const files = await client.listPullFiles(repo.owner, repo.name, pull.number);
        const head = String(pull.head_sha);
        // What the controller maps the change onto the mesh's module graph with (novox/hq ADR 0237 as
        // amended): which changed directories hold a module at the head — the merge's rule (issue 278) —
        // and whether the head holds the repository's own merge-check.sh. Not said when it could not be
        // read; the controller then reads the change as touching everything built from the repository.
        let moduleDirs: string[] | null = null;
        let mergeCheck: boolean | null = null;
        try {
          if (!files.truncated) moduleDirs = await client.moduleDirsAt(repo.owner, repo.name, head, files.paths);
          mergeCheck = await client.holdsFile(repo.owner, repo.name, head, "merge-check.sh");
        } catch (err) {
          console.error(`[gitea] ${key}: what the head holds could not be read — ${err instanceof Error ? err.message : err}`);
        }
        await emit("pull.updated", {
          owner: repo.owner,
          repo: repo.name,
          number: pull.number,
          title: pull.title,
          body: pull.body,
          base: pull.base,
          head: pull.head,
          head_sha: pull.head_sha,
          clone_url: repo.clone_url,
          html_url: pull.html_url,
          paths: files.paths,
          paths_truncated: files.truncated,
          removed: files.removed,
          ...(moduleDirs ? { module_dirs: moduleDirs, module_dirs_said: true } : {}),
          ...(mergeCheck !== null ? { merge_check: mergeCheck, merge_check_said: true } : {}),
        });
        // Said, so an operator knows the mesh was asked to check it.
        console.log(`[gitea] announced ${key} at ${String(pull.head_sha).slice(0, 8)} to be checked before it merges`);
        // Pending until the verdict comes, so the pull request says a check is running rather than nothing.
        await client
          .setCommitStatus(repo.owner, repo.name, String(pull.head_sha), {
            state: "pending", context: CHECK_CONTEXT, description: "the mesh is mapping this head onto its module graph",
          })
          .catch((err) => console.error(`[gitea] ${key}: could not say a check is pending — ${err instanceof Error ? err.message : err}`));
      }
      heads[key] = String(pull.head_sha);
      changed = true;
    }
  }
  if (!primedPulls || changed) keepHeads();
  primedPulls = true;
  lastPullLook = began;
}

// **The verdict, set where the pull request shows it.** Every verdict is the head commit's status; one
// that is not a pass also leaves the check's own account as a comment, so the reason is read where the
// change is reviewed. An error — the check could not run — is the forge's `error`, never a success.
async function setVerdict(client: GiteaClient, event: { body: unknown }): Promise<void> {
  const c = (event.body ?? {}) as Checked;
  if (c.group) {
    // A delivery group's composed check (novox/hq ADR 0239): its verdict is the group owner's to say, on each
    // member's head, as mesh/delivery-group — never this head's merge gate.
    return;
  }
  if (!c.owner || !c.repo || !c.commit || !c.verdict) {
    console.error("[gitea] a merge check's verdict named no repository, commit or verdict; ignored");
    return;
  }
  // Each status links to the pull request, where the delivery's view is kept (novox/hq ADR 0239).
  let target: string | undefined;
  let base: string | undefined;
  if (c.number) {
    const pull = await client.getPullRequest(c.owner, c.repo, c.number).catch(() => undefined);
    target = pull?.html_url || undefined;
    base = pull?.base || undefined;
  }
  const facts = await repoCheckFacts(client, c, base ?? c.plan?.base);
  for (const status of statusesFor(c, facts)) {
    await client.setCommitStatus(c.owner, c.repo, c.commit, target ? { ...status, target_url: target } : status);
  }
  const comment = commentFor(c, facts);
  if (comment && c.number) await client.addComment(c.owner, c.repo, c.number, comment);
  console.log(`[gitea] ${c.owner}/${c.repo}#${c.number ?? "?"} at ${c.commit.slice(0, 8)}: merge check ${c.verdict}`);
}

// **What only the forge knows of a repository check said as a warning** (novox/hq issue 293): whether the
// head holds a merge-check.sh at all, and — when it does not — whether the base branch's protection
// requires mesh/repo-check. Asked only for a warning; unknown is left undefined, which statusesFor reads
// as possibly required: a failure on a status nothing requires blocks nothing, a success on one that is
// required would let an untested repository merge.
async function repoCheckFacts(client: GiteaClient, c: Checked, base: string | undefined): Promise<RepoCheckFacts> {
  if (c["repo-check"]?.verdict !== "warning") return {};
  const defined = await client.holdsFile(c.owner, c.repo, c.commit, "merge-check.sh").catch(() => undefined);
  if (defined !== false) return { defined };
  const rules = await client.branchProtections(c.owner, c.repo).catch(() => undefined);
  if (!rules) return { defined };
  const rule = rules.find((p) => (p.rule_name ?? p.branch_name) === (base || "main"));
  const required = !!rule?.enable_status_check && (rule.status_check_contexts ?? []).includes(REPO_CHECK_CONTEXT);
  return { defined, required };
}

if (gitea) {
  const client = gitea;
  // A poll that fails says so once, not once a minute: the same reason repeating (the forge not up
  // yet, the admin account refused on a restored forge) is one fact, and a recovery is worth a line.
  let failing: string | null = null;
  const tick = (fn: () => Promise<void>, everyMs: number): void => {
    // **One pass at a time** (novox/hq issue 250): the next pass is scheduled when this one has ended, so a
    // pass that outlasts its interval delays the next instead of running beside it — two passes at once
    // could each announce the same merge before either recorded it.
    const run = (): void =>
      void fn()
        .then(() => {
          if (failing !== null) console.log("[gitea] watching again");
          failing = null;
        })
        .catch((err) => {
          const why = err instanceof Error ? err.message : String(err);
          if (why !== failing) console.error(`[gitea] not watching until this clears — ${why}`);
          failing = why;
        })
        .finally(() => setTimeout(run, everyMs));
    run();
  };
  tick(() => pollRepos(client), 60_000);
  tick(() => pollMerged(client), 30_000);
  tick(() => pollPulls(client), 30_000);
  await on("mesh-controller.checked", (event) => setVerdict(client, event));
  console.log("[gitea] watching for new repositories and merged pull requests");
}