import { assertEquals, assertRejects } from "@std/assert";
import { BACKGROUND_CONTEXT as context } from "@earendil-works/chord/context";
import { type Message, Type } from "@earendil-works/pi-ai";
import { fauxAssistantMessage, fauxToolCall } from "@earendil-works/pi-ai/providers/faux";
import { defineExtension, type JsonValue } from "@berry/api";
import { BerryError } from "./berry.ts";
import { sectionsSeen, setup } from "./fixture.ts";

const configurable = defineExtension<
  { cwd: string; verbose: boolean; edits: number },
  { cwd: string; verbose: boolean }
>({
  name: "configurable",
  initial: () => ({ cwd: "/", verbose: false, edits: 0 }),
  apply: (state, event) => ({ ...state, ...event, edits: state.edits + 1 }),
  setup(ext) {
    ext.configuration({
      parameters: Type.Object({
        cwd: Type.String({ default: "/" }),
        verbose: Type.Boolean({ default: false }),
      }),
      values: ({ cwd, verbose }) => ({ cwd, verbose }),
      events: ({ cwd, verbose }) => {
        if (!cwd.startsWith("/")) throw new Error(`not absolute: ${cwd}`);
        return [{ cwd, verbose }];
      },
    });
    return (conv) => conv.prompt(() => `cwd: ${conv.state.cwd}`);
  },
});

Deno.test("configuration seeds new conversations and exposes only editable state", async () => {
  await using harness = await setup();
  const { berry } = harness;
  await berry.install(configurable);
  const tid = await berry.create({ extensions: { configurable: { cwd: "/seed" } } });
  const feed = (await berry.watchConfiguration(tid, "configurable"))!;
  assertEquals(feed.value, { cwd: "/seed", verbose: false });
  await feed.stop();
  const defaults = await berry.create({ extensions: { configurable: {} } });
  assertEquals(await berry.state(defaults, "configurable"), {
    cwd: "/",
    verbose: false,
    edits: 1,
  });
  await assertRejects(
    () => berry.create({ extensions: { configurable: { cwd: 5 } } }),
    BerryError,
    "cwd",
  );
  await assertRejects(
    () => berry.create({ extensions: { configurable: { cwd: "relative" } } }),
    BerryError,
    "not absolute",
  );
});

Deno.test("configuration patches preserve other fields, validate before writing, and replay from events", async () => {
  await using harness = await setup();
  const { berry } = harness;
  await berry.install(configurable);
  const tid = await berry.create({ extensions: { configurable: { cwd: "/seed" } } });
  assertEquals(await berry.configureExtension(tid, "configurable", { verbose: true }), {
    cwd: "/seed",
    verbose: true,
  });
  const invalid: Record<string, JsonValue>[] = [{ cwd: 5 }, { cwd: "relative" }, { edits: 999 }];
  for (const change of invalid) {
    await assertRejects(() => berry.configureExtension(tid, "configurable", change), BerryError);
  }
  await berry.install(configurable);
  assertEquals(await berry.state(tid, "configurable"), { cwd: "/seed", verbose: true, edits: 2 });
  await berry.configure(tid, { extensions: [] });
  await assertRejects(
    () => berry.configureExtension(tid, "configurable", { cwd: "/disabled" }),
    BerryError,
    "no enabled configuration",
  );
  await assertRejects(() => berry.configureExtension(tid, "missing", {}), BerryError);
});

Deno.test("a configuration edit lands at once while busy and reaches the turn's next request", async () => {
  await using harness = await setup();
  const { berry, faux, model, gate } = harness;
  try {
    await berry.install(configurable);
    const tid = await berry.create({ extensions: { configurable: {}, gate: {} }, model });
    let next: readonly Message[] = [];
    faux.setResponses([
      fauxAssistantMessage(fauxToolCall("hold", {}), { stopReason: "toolUse" }),
      (ctx) => (next = ctx.messages, fauxAssistantMessage("done")),
    ]);
    const conversation = (await berry.conversation(tid))!;
    const submission = await conversation.submit({ type: "input", content: "go" }, context);
    await gate.entered.promise;
    assertEquals(await berry.configureExtension(tid, "configurable", { cwd: "/mid" }), {
      cwd: "/mid",
      verbose: false,
    });
    assertEquals(await berry.state(tid, "configurable"), { cwd: "/mid", verbose: false, edits: 2 });
    gate.release.resolve("released");
    await submission.wait(context);
    await conversation.waitForIdle(context);
    assertEquals(
      sectionsSeen(next).at(-1)?.configurable,
      "<configurable>\ncwd: /mid\n</configurable>",
    );
  } finally {
    gate.release.resolve("released");
  }
});