import { chmod, copyFile, mkdtemp, rm } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join, resolve } from "node:path";
import { expect, it } from "vitest";
import { OpenCodeServerDriver } from "./opencode-server-driver.js";
import type { PrpEvent } from "../../protocol/replay-contract.js";

it.each(["reply", "empty-again", "request-fails", "normal", "foreign-idle"] as const)("handles an empty OpenCode response: %s", async mode => {
  const root = await mkdtemp(join(tmpdir(), "opencode-empty-response-"));
  const command = join(root, "fake-opencode.mjs");
  await copyFile(resolve("test/fixtures/fake-opencode-server.mjs"), command);
  await chmod(command, 0o755);
  const prompts: Record<string, any>[] = [];
  let stream: ReadableStreamDefaultController<Uint8Array> | undefined;
  const queued: Uint8Array[] = [];
  const emit = (value: unknown) => { const frame = new TextEncoder().encode(`data: ${JSON.stringify(value)}\n\n`); if (stream) stream.enqueue(frame); else queued.push(frame); };
  const driver = new OpenCodeServerDriver({
    model: "openrouter/controlled-model", runtimeDirectory: join(root, "runtime"), command,
    environment: { PATH: process.env.PATH, OPENROUTER_API_KEY: "controlled-fixture-key" },
    fetch: async (input, init) => {
      const url = new URL(String(input));
      if (url.pathname === "/event") return new Response(new ReadableStream<Uint8Array>({ start(controller) { stream = controller; for (const frame of queued.splice(0)) controller.enqueue(frame); } }), { headers: { "Content-Type": "text/event-stream" } });
      if (url.pathname.endsWith("/prompt_async")) {
        const prompt = JSON.parse(String(init?.body)); prompts.push(prompt);
        if (prompts.length === 2 && mode === "request-fails") throw new Error("controlled correction request failed");
        const sessionID = decodeURIComponent(url.pathname.split("/")[2]!);
        const number = prompts.length, messageID = `assistant-${number}`;
        queueMicrotask(() => {
          if (mode === "foreign-idle") emit({ type: "session.idle", properties: { sessionID: "foreign-session" } });
          emit({ type: "message.updated", properties: { info: { id: messageID, sessionID, role: "assistant", finish: "stop", time: { completed: Date.now() } } } });
          const answer = mode === "normal" || mode === "foreign-idle" || number === 2 && mode === "reply";
          emit({ type: "message.part.updated", properties: { sessionID, part: { id: `part-${number}`, messageID,
            type: answer ? "text" : "reasoning", text: answer ? "Here is the actual final answer." : "Synthetic reasoning must not become the answer.", time: { start: 1, end: 2 } } } });
          emit({ type: "session.idle", properties: { sessionID } });
          emit({ type: "session.status", properties: { sessionID, status: { type: "idle" } } });
        });
        return new Response(null, { status: 204 });
      }
      return fetch(input, init);
    },
  });
  const session = await driver.openSession({ runId: "owned-run", normalizedSessionId: "owned-session", workingDirectory: root });
  try {
    const collected = (async () => { const rows: PrpEvent[] = []; for await (const event of session.events()) {
      rows.push(event); if (["turn.completed", "turn.failed"].includes(event.eventType)) break;
    } return rows; })();
    const { turnId } = await session.startTurn({ message: { role: "user", text: "Answer the current request." }, reasoningMode: "disabled" });
    const events = await collected;
    const succeeds = ["reply", "normal", "foreign-idle"].includes(mode);
    expect(events.at(-1)?.eventType).toBe(succeeds ? "turn.completed" : "turn.failed");
    expect(events.filter(event => event.eventType === "turn.started")).toHaveLength(1);
    expect(events.every(event => !event.turnId || event.turnId === turnId)).toBe(true);
    const final = events.filter(event => event.eventType === "item.completed" && event.payload.kind === "agentMessage" && event.payload.channel === "final");
    expect(final.map(event => event.payload.text)).toEqual(succeeds ? ["Here is the actual final answer."] : []);
    expect(prompts).toHaveLength(["normal", "foreign-idle"].includes(mode) ? 1 : 2);
    if (prompts.length === 2) {
      expect(prompts[1]).toMatchObject({ providerID: prompts[0]!.providerID, modelID: prompts[0]!.modelID, system: prompts[0]!.system, variant: "paperclip-no-reasoning" });
      expect(JSON.stringify(prompts[1]!.parts)).toContain("Do not repeat completed actions");
    }
  } finally {
    await session.close({ reason: "controlled test complete" });
    await rm(root, { recursive: true, force: true });
  }
}, 30_000);