import { assert, assertEquals, assertRejects, assertStringIncludes } from "@std/assert";
import { BACKGROUND_CONTEXT as context } from "@earendil-works/chord/context";
import { Type } from "@earendil-works/pi-ai";
import { fauxAssistantMessage, fauxToolCall } from "@earendil-works/pi-ai/providers/faux";
import { mkdir, symlink, writeFile } from "node:fs/promises";
import { homedir } from "node:os";
import { join } from "node:path";
import { defineExtension } from "@berry/api";
import { type Environment, localEnvironment } from "@berry/api/environment.ts";
import { BerryError, Settings } from "./berry.ts";
import { type Environments, type EnvironmentSettings, localOnly } from "./environment.ts";
import { lastToolResult, script, sectionsSeen, setup, turn } from "./fixture.ts";
import { tempDir } from "@berry/util";

/**
 * This machine as `local`, a directory of it posing as a machine named `other`, and a machine named `down` that
 * cannot be reached.
 */
function twoMachines(otherHome: string): Environments {
  return {
    open(name, cwd, during) {
      if (name === "down") return Promise.reject(new Error("down is unreachable"));
      if (name !== "other") return localOnly.open(name, cwd, during);
      const env: Environment = Object.assign(localEnvironment(cwd ?? otherHome), {
        name,
        home: otherHome,
      });
      return Promise.resolve(env);
    },
    close: () => Promise.resolve(),
  };
}

async function withDirectories(test: (root: string) => Promise<void>) {
  await using rootDir = await tempDir({ prefix: "berry-environment-" });
  const root = rootDir.path;
  await mkdir(join(root, "a"));
  await mkdir(join(root, "b"));
  await mkdir(join(root, "other"));
  await writeFile(join(root, "file"), "");
  await symlink(join(root, "a"), join(root, "link"));
  await test(root);
}

Deno.test("a conversation works in the local home until bound to a directory its machine resolves, which /cd moves", () =>
  withDirectories(async (root) => {
    await using harness = await setup(twoMachines(join(root, "other")));
    const { berry, model } = harness;
    const home = await berry.create({ extensions: {}, model });
    assertEquals(await berry.state(home, "environment"), { environment: "local", cwd: null });
    const env = await berry.environment(home);
    assertEquals([env.name, env.cwd], ["local", homedir()]);

    const tid = await berry.create({
      extensions: { environment: { cwd: join(root, "link") } },
      model,
    });
    assertEquals((await berry.environment(tid)).cwd, join(root, "a"));
    for (const cwd of [join(root, "file"), join(root, "missing")]) {
      await assertRejects(() => berry.create({ extensions: { environment: { cwd } }, model }));
    }
    await assertRejects(
      () => berry.create({ extensions: { environment: { environment: "elsewhere" } }, model }),
      BerryError,
      "No environment named elsewhere",
    );
    await berry.configureExtension(tid, "environment", { cwd: "../b" });
    assertEquals((await berry.environment(tid)).cwd, join(root, "b"));

    const other = await berry.create({
      extensions: { environment: { environment: "other", cwd: join(root, "a") } },
      model,
    });
    assertEquals(await berry.command(other, "cd", "../link"), join(root, "a"));
    assertEquals(await berry.command(other, "cd", " ../b "), join(root, "b"));
    await assertRejects(() => berry.command(other, "cd", "../file"), BerryError, "Not a directory");
    await assertRejects(() => berry.command(other, "cd", "missing"), BerryError);
    // home is the machine's
    assertEquals(await berry.command(other, "cd", ""), join(root, "other"));
    assertEquals(await berry.state(other, "environment"), {
      environment: "other",
      cwd: join(root, "other"),
    });
  }));

Deno.test("the code extension's working directory carries over from old history", async () => {
  await using harness = await setup();
  const { berry, model } = harness;
  const tid = await berry.create({ extensions: {}, model });
  await (await berry.emit(tid, "coding", { type: "cd", cwd: "/first" })).wait(context);
  assertEquals(await berry.state(tid, "environment"), { environment: "local", cwd: "/first" });
  await (await berry.emit(tid, "code", { type: "cd", cwd: "/second" })).wait(context);
  assertEquals(await berry.state(tid, "environment"), { environment: "local", cwd: "/second" });
});

Deno.test("only an idle conversation moves to another machine; a new directory waits for the boundary", () =>
  withDirectories(async (root) => {
    await using harness = await setup(twoMachines(join(root, "other")));
    const { berry, model, faux, gate } = harness;
    const tid = await berry.create({
      extensions: { environment: { cwd: join(root, "a") }, gate: {} },
      model,
    });
    faux.setResponses([
      fauxAssistantMessage(fauxToolCall("hold", {}), { stopReason: "toolUse" }),
      fauxAssistantMessage("done"),
    ]);
    const conversation = (await berry.conversation(tid))!;
    await conversation.submit({ type: "input", content: "go" }, context);
    await gate.entered.promise;

    await assertRejects(
      () => berry.configureExtension(tid, "environment", { environment: "other" }),
      BerryError,
      "busy",
    );
    const moved = berry.configureExtension(tid, "environment", { cwd: join(root, "b") });
    assertEquals(await berry.state(tid, "environment"), {
      environment: "local",
      cwd: join(root, "a"),
    });
    gate.release.resolve("released");
    assertEquals(await moved, { environment: "local", cwd: join(root, "b") });
    await conversation.waitForIdle(context);

    // the form still holds this machine's directory, which means nothing on the other
    assertEquals(
      await berry.configureExtension(tid, "environment", {
        environment: "other",
        cwd: join(root, "b"),
      }),
      { environment: "other", cwd: join(root, "other") },
    );
    const env = await berry.environment(tid);
    assertEquals([env.name, env.cwd], ["other", join(root, "other")]);
  }));

/** Reports the environment wherever an extension meets it. */
const probe = defineExtension({
  name: "probe",
  initial: () => null,
  setup(ext) {
    const where = (env: Environment) => `${env.name}:${env.cwd}`;
    ext.tool({
      name: "where",
      description: "where calls run",
      parameters: Type.Object({}),
      execute: (_, ctx) => where(ctx.env),
    });
    ext.prompt("named", ({ env }) => env && `named ${where(env)}`);
    return (conv) => {
      conv.prompt(({ env }) => env && `in ${where(env)}`);
      conv.command({ name: "go", description: "", execute: (path, ctx) => ctx.cd(path) });
      conv.command({ name: "here", description: "", execute: (_, ctx) => where(ctx.env) });
      conv.command({ name: "ping", description: "", execute: () => "pong" });
    };
  },
});

Deno.test("calls, prompts, and commands all meet the conversation's environment, and fail with a machine out of reach", () =>
  withDirectories(async (root) => {
    await using harness = await setup(twoMachines(join(root, "other")));
    const { berry, model } = harness;
    await berry.install(probe);
    const tid = await berry.create({
      extensions: { environment: { cwd: join(root, "a") }, probe: {} },
      model,
    });
    const seen = await turn(harness, tid, [script("text(await tools.where({}))")]);
    assertEquals(lastToolResult(seen[1]).text, `Script completed\nlocal:${join(root, "a")}`);
    const sections = sectionsSeen(seen[0])[0];
    assertEquals(sections.probe, `<probe>\nin local:${join(root, "a")}\n</probe>`);
    assertEquals(
      sections.probe_named,
      `<probe_named>\nnamed local:${join(root, "a")}\n</probe_named>`,
    );
    assertEquals(sections.environment, undefined);

    assertEquals(await berry.command(tid, "go", "../b"), join(root, "b"));
    assertEquals(await berry.command(tid, "here", ""), `local:${join(root, "b")}`);
    await berry.configureExtension(tid, "environment", { environment: "other" });
    const [moved] = await turn(harness, tid, []);
    assertEquals(
      sectionsSeen(moved).at(-1)?.probe,
      `<probe>\nin other:${join(root, "other")}\n</probe>`,
    );
    assertEquals(
      sectionsSeen(moved).at(-1)?.environment?.includes("files and commands are on other"),
      true,
    );

    // as though it went down after the conversation moved there
    await (await berry.emit(tid, "environment", { type: "bind", environment: "down", cwd: "/" }))
      .wait(context);
    const down = await turn(harness, tid, [script("text(await tools.where({}))")]);
    const result = lastToolResult(down[1]);
    assertEquals(result.isError, true);
    assertEquals(result.text.includes("down is unreachable"), true);
    const unreachable = sectionsSeen(down[0]).at(-1)!;
    assertEquals(unreachable.probe, null);
    assertEquals(unreachable.environment?.includes("down cannot be reached"), true);
    assertEquals(await berry.command(tid, "ping", ""), "pong");
    await assertRejects(() => berry.command(tid, "here", ""), BerryError, "down is unreachable");
  }));

Deno.test("disabling local fails its turns without contacting the model, but remote turns and recovery still work", async () => {
  await using root = await tempDir();
  await using harness = await setup(twoMachines(root.path));
  const { berry, model, faux } = harness;
  const tid = await berry.create({ extensions: {}, model });
  await berry.setAllowLocalEnvironment(false);

  const calls = faux.state.callCount;
  assertEquals(await turn(harness, tid, []), []);
  assertEquals(faux.state.callCount, calls);
  const conversation = (await berry.conversation(tid))!;
  const entries = await conversation.entries({ order: "ascending" }, 100, undefined, context);
  const failure = entries.items.flatMap((entry) => entry.model ?? []).findLast((message) =>
    message.role === "assistant"
  );
  assert(failure?.role === "assistant");
  assertEquals(failure.stopReason, "error");
  assertStringIncludes(failure.errorMessage ?? "", "local environment is disabled");
  await assertRejects(() => berry.environment(tid), BerryError, "local environment is disabled");
  await assertRejects(
    () => berry.command(tid, "cd", ""),
    BerryError,
    "local environment is disabled",
  );

  await berry.configureExtension(tid, "environment", { environment: "other" });
  assertEquals((await turn(harness, tid, [])).length, 1);
  await assertRejects(
    () => berry.configureExtension(tid, "environment", { environment: "local" }),
    BerryError,
    "local environment is disabled",
  );
  await berry.setAllowLocalEnvironment(true);
  await berry.configureExtension(tid, "environment", { environment: "local" });
  assertEquals((await turn(harness, tid, [])).length, 1);
});

Deno.test("settings name the other machines, and nothing ssh could take for an option", async () => {
  await using harness = await setup();
  const { berry } = harness;
  const refusals: Record<string, EnvironmentSettings>[] = [
    { local: { ssh: "elsewhere" } },
    { "-oProxyCommand=x": { ssh: "elsewhere" } },
    { devbox: { ssh: "-oProxyCommand=x" } },
    { devbox: { ssh: " " } },
    { devbox: { ssh: "devbox", deno: "" } },
  ];
  for (const refused of refusals) {
    await assertRejects(() => berry.setEnvironments(refused), BerryError);
  }
  await berry.setEnvironments({ devbox: { ssh: " me@devbox ", deno: "/opt/deno" } });
  assertEquals((await berry.harness.snapshot(Settings, context))?.environments, {
    devbox: { ssh: "me@devbox", deno: "/opt/deno" },
  });
});