/**
 * The work after the response: a drawing row is made at once (status
 * `drawing`) and this fills it in when Claude answers — `done` with its SVGs,
 * or `failed` with a sentence a person can act on. Each change is emitted,
 * so the page updates live.
 *
 * The drawer is set once at boot (`src/server.ts`) from the environment; a
 * test sets its own. With no token there is still a drawer: one that says
 * what to set, so the page never just spins.
 */

import type { Database } from "bun:sqlite";
import { claudeRunner, drawArgs, resultText, type RunClaude } from "./claude.ts";
import { ask, COUNT, parseReply, type Kind } from "./glyph.ts";
import { emit } from "./live.ts";

/** A prompt and a kind in, the kept SVGs out — or a thrown Error whose message a person reads. */
export type Drawer = (prompt: string, kind: Kind) => Promise<string[]>;

export const NO_TOKEN =
  "Drawing needs a Claude token: set CLAUDE_CODE_OAUTH_TOKEN in Settings → App → Environment (from `claude setup-token`), then try again.";

let drawer: Drawer = async () => {
  throw new Error(NO_TOKEN);
};

export function setDrawer(next: Drawer): void {
  drawer = next;
}

/** A drawer over Claude Code. */
export function claudeDrawer(run: RunClaude): Drawer {
  return async (prompt, kind) => {
    const answer = resultText(await run(drawArgs(), ask(prompt, kind)));
    if (!answer.ok) throw new Error(answer.why);
    const svgs = parseReply(answer.text);
    if (svgs.length === 0) throw new Error("Claude answered, but no drawing in it passed the checks. Try again.");
    return svgs.slice(0, COUNT);
  };
}

/** The drawer this process uses, from what the forge told it. */
export function drawerFromEnv(
  dataDir: string,
  from: Readonly<Record<string, string | undefined>> = process.env,
): Drawer | undefined {
  const token = from.CLAUDE_CODE_OAUTH_TOKEN ?? "";
  return token === "" ? undefined : claudeDrawer(claudeRunner(token, dataDir));
}

/** The work in flight, so a test (or a shutdown) can wait for it. */
const running = new Set<Promise<void>>();
export const settled = (): Promise<unknown> => Promise.all([...running]);

/** Fill in drawing `id` in the background. */
export function kick(db: Database, id: number, prompt: string, kind: Kind): void {
  const job = (async () => {
    let row: { id: number; status: string } | null;
    try {
      const svgs = await drawer(prompt, kind);
      row = db
        .query("UPDATE drawing SET status = 'done', svgs = ?1, error = NULL, updated_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now') WHERE id = ?2 AND status = 'drawing' RETURNING *")
        .get(JSON.stringify(svgs), id);
    } catch (error) {
      const message = error instanceof Error ? error.message : String(error);
      row = db
        .query("UPDATE drawing SET status = 'failed', error = ?1, updated_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now') WHERE id = ?2 AND status = 'drawing' RETURNING *")
        .get(message.slice(0, 500), id);
    }
    if (row !== null) emit("drawing.changed", { id: row.id, status: row.status });
  })().catch((error) => console.error("drawing", id, error));
  running.add(job);
  void job.finally(() => running.delete(job));
}

/** Drawings a stopped process left half done are failed, so nobody waits on them forever. */
export function recover(db: Database): number {
  return db
    .query("UPDATE drawing SET status = 'failed', error = 'Interrupted: the app restarted while drawing. Try again.' WHERE status = 'drawing'")
    .run().changes;
}