import type { AgentMessage } from "@earendil-works/pi-agent-core";
import { beforeEach, describe, expect, it, vi } from "vitest";

const fakeAgentState = vi.hoisted(() => ({
  thinkingLevels: [] as string[],
  transforms: [] as Array<(messages: AgentMessage[]) => Promise<AgentMessage[]>>,
  models: [] as Array<{
    id: string;
    provider: string;
    reasoning: boolean;
    contextWindow?: number;
    maxTokens?: number;
  }>,
  sessionIds: [] as Array<string | undefined>,
  subagentArgs: { name: "helper", task: "help" } as Record<string, unknown>,
  lastSubagentResult: undefined as unknown,
  failPrompt: false,
  abortCalls: 0,
}));

type FakeAgentTool = {
  name: string;
  execute: (toolCallId: string, params: Record<string, unknown>) => Promise<unknown>;
};

vi.mock("@earendil-works/pi-agent-core", () => ({
  Agent: class {
    state = { errorMessage: undefined, messages: [] };
    private readonly tools: FakeAgentTool[];

    constructor(options: {
      sessionId?: string;
      transformContext: (messages: AgentMessage[]) => Promise<AgentMessage[]>;
      initialState: {
        thinkingLevel: string;
        tools: FakeAgentTool[];
        model: (typeof fakeAgentState.models)[number];
      };
    }) {
      this.tools = options.initialState.tools;
      fakeAgentState.transforms.push(options.transformContext);
      fakeAgentState.sessionIds.push(options.sessionId);
      fakeAgentState.thinkingLevels.push(options.initialState.thinkingLevel);
      fakeAgentState.models.push(options.initialState.model);
    }

    subscribe(_listener: unknown) {}
    async prompt() {
      if (fakeAgentState.failPrompt) throw new Error("prompt failed");
      const runSubagent = this.tools.find((tool) => tool.name === "run_subagent");
      fakeAgentState.lastSubagentResult = await runSubagent?.execute(
        "subagent-call",
        fakeAgentState.subagentArgs,
      );
    }
    async waitForIdle() {}
    abort() {
      fakeAgentState.abortCalls += 1;
    }
  },
}));

vi.mock("@earendil-works/pi-ai/providers/all", () => ({
  builtinModels: () => ({
    getModel: (_provider: string, modelId: string) => {
      if (modelId === "reasoning-model") return { provider: "test", id: modelId, reasoning: true };
      if (modelId === "plain-model") return { provider: "test", id: modelId, reasoning: false };
      if (modelId === "grok-4.6") {
        return {
          provider: "xai",
          id: modelId,
          reasoning: true,
          thinkingLevelMap: {
            off: null,
            minimal: null,
            low: "low",
            medium: "medium",
            high: "high",
            xhigh: "xhigh",
            max: null,
          },
        };
      }
      return undefined;
    },
    streamSimple: () => {
      throw new Error("the fake agent must not call a provider");
    },
  }),
}));

vi.mock("./pi-local-provider.js", () => ({
  registerLocalProvider: (models: unknown) => models,
}));

vi.mock("./pi-openai-compatible-provider.js", () => ({
  OPENAI_COMPATIBLE_PROVIDER_ID: "openai-compatible",
  registerOpenAiCompatibleCatalog: (models: unknown) => models,
  registerOpenAiCompatibleRuntime: (models: unknown) => models,
}));

import { PiAgentRuntime } from "./pi-runtime.js";

async function runWithModel(
  modelId: string,
  provider = "test",
  signal = new AbortController().signal,
  thinkingLevel?: "off" | "minimal" | "low" | "medium" | "high" | "xhigh" | "max" | null,
  resolveModel?: (
    provider: string,
    modelId: string,
  ) => Promise<{
    provider: string;
    id: string;
    apiKey?: string;
    maxImagesPerPrompt?: number;
    thinkingLevel?: "off" | "minimal" | "low" | "medium" | "high" | "xhigh" | "max" | null;
  }>,
  maxImagesPerPrompt?: number,
) {
  const runtime = new PiAgentRuntime();
  for await (const _event of runtime.run(
    {
      botId: "b",
      threadId: "t",
      runId: "r",
      prompt: "hello",
      instructions: "",
      history: [],
      tools: [],
      model: { provider, id: modelId, thinkingLevel, maxImagesPerPrompt },
      executeTool: vi.fn(async () => ({ ok: true })),
      resolveModel,
    },
    {
      operationId: "1",
      traceId: "1",
      spaceId: "w",
      userId: "u",
      signal,
    },
  )) {
    // Exhaust the runtime event stream so the run completes.
  }
  return fakeAgentState.thinkingLevels;
}

describe("Pi agent thinking level", () => {
  beforeEach(() => {
    fakeAgentState.thinkingLevels = [];
    fakeAgentState.transforms = [];
    fakeAgentState.models = [];
    fakeAgentState.sessionIds = [];
    fakeAgentState.subagentArgs = { name: "helper", task: "help" };
    fakeAgentState.lastSubagentResult = undefined;
    fakeAgentState.failPrompt = false;
    vi.unstubAllEnvs();
  });

  it("uses medium reasoning for the main agent and subagent", async () => {
    // Regression for OpenRouter mandatory-reasoning models (#114): forcing
    // thinkingLevel "off" becomes effort "none" and the provider returns 400.
    const levels = await runWithModel("reasoning-model");
    expect(levels).toEqual(["medium", "medium"]);
    expect(levels.every((level) => level !== "off")).toBe(true);
  });

  it("uses a stable provider session for each bot thread", async () => {
    await runWithModel("plain-model");

    expect(fakeAgentState.sessionIds[0]).toBe("t:b");
  });

  it("honors a per-bot thinking level on reasoning models", async () => {
    const levels = await runWithModel("grok-4.6", "xai", new AbortController().signal, "high");
    expect(levels).toEqual(["high", "high"]);
  });

  it("resolves and runs an explicitly selected subagent model", async () => {
    fakeAgentState.subagentArgs = {
      name: "helper",
      task: "help",
      model_provider: "xai",
      model_id: "grok-4.6",
    };
    const resolveModel = vi.fn(async (provider: string, modelId: string) => ({
      provider,
      id: modelId,
      apiKey: "subagent-key",
      thinkingLevel: "high" as const,
    }));

    const levels = await runWithModel(
      "plain-model",
      "test",
      new AbortController().signal,
      null,
      resolveModel,
    );

    expect(resolveModel).toHaveBeenCalledWith("xai", "grok-4.6");
    expect(fakeAgentState.models.map((model) => `${model.provider}/${model.id}`)).toEqual([
      "test/plain-model",
      "xai/grok-4.6",
    ]);
    expect(levels).toEqual(["off", "high"]);
  });

  it.each([
    { parentLimit: 2, childLimit: 1, expected: 1 },
    { parentLimit: 1, childLimit: 2, expected: 2 },
    { parentLimit: 2, childLimit: 0, expected: 0 },
    { parentLimit: 0, childLimit: undefined, expected: 2 },
  ])(
    "uses the selected subagent image budget: $parentLimit -> $childLimit",
    async ({ parentLimit, childLimit, expected }) => {
      fakeAgentState.subagentArgs = {
        name: "helper",
        task: "inspect screenshots",
        model_provider: "test",
        model_id: "plain-model",
      };
      await runWithModel(
        "plain-model",
        "test",
        new AbortController().signal,
        null,
        async () => ({ provider: "test", id: "plain-model", maxImagesPerPrompt: childLimit }),
        parentLimit,
      );
      const screenshots: AgentMessage[] = [0, 1].map((index) => ({
        role: "toolResult",
        toolCallId: `capture-${index}`,
        toolName: "computer_observe",
        content: [{ type: "image", data: "fake-image", mimeType: "image/png" }],
        details: { frameId: `frame-${index}` },
        isError: false,
        timestamp: index,
      }));
      const countImages = (messages: AgentMessage[]) =>
        messages.reduce(
          (count, message) =>
            count +
            ("content" in message && Array.isArray(message.content)
              ? message.content.filter((part) => part.type === "image").length
              : 0),
          0,
        );
      const [parentTransform, childTransform] = fakeAgentState.transforms;
      if (!parentTransform || !childTransform) throw new Error("missing agent transforms");
      expect(countImages(await parentTransform(screenshots))).toBe(parentLimit);
      expect(countImages(await childTransform(screenshots))).toBe(expected);
    },
  );

  it("rejects an incomplete per-call subagent model pair", async () => {
    fakeAgentState.subagentArgs = {
      name: "helper",
      task: "help",
      model_provider: "xai",
    };
    const resolveModel = vi.fn();

    await runWithModel("plain-model", "test", new AbortController().signal, null, resolveModel);

    expect(resolveModel).not.toHaveBeenCalled();
    expect(fakeAgentState.lastSubagentResult).toMatchObject({
      details: { result: "Subagent failed: model_provider and model_id must both be set" },
    });
  });

  it("surfaces a scoped model-resolution failure without starting the helper", async () => {
    fakeAgentState.subagentArgs = {
      name: "helper",
      task: "help",
      model_provider: "anthropic",
      model_id: "claude-opus-4-6",
    };
    const resolveModel = vi.fn(async () => {
      throw new Error("Connect that model provider first");
    });

    await runWithModel("plain-model", "test", new AbortController().signal, null, resolveModel);

    expect(resolveModel).toHaveBeenCalledWith("anthropic", "claude-opus-4-6");
    expect(fakeAgentState.models).toHaveLength(1);
    expect(fakeAgentState.lastSubagentResult).toMatchObject({
      details: { result: "Subagent failed: Connect that model provider first" },
    });
  });

  it("keeps reasoning off for the main agent and subagent", async () => {
    expect(await runWithModel("plain-model")).toEqual(["off", "off"]);
  });

  it("normalizes and runs a configured OpenRouter model absent from the static catalog", async () => {
    vi.stubEnv("PI_DEFAULT_PROVIDER", " openrouter ");
    vi.stubEnv("PI_DEFAULT_MODEL", "  stealth/ox-alpha  ");

    const levels = await runWithModel("  stealth/ox-alpha  ", "openrouter");

    expect(fakeAgentState.models).toHaveLength(2);
    expect(fakeAgentState.models[0]).toMatchObject({
      id: "stealth/ox-alpha",
      provider: "openrouter",
      reasoning: true,
      contextWindow: 16_384,
      maxTokens: 4_096,
    });
    // Unknown OpenRouter PI_DEFAULT_MODEL must not force thinking off (#114).
    expect(levels).toEqual(["medium", "medium"]);
    expect(levels.every((level) => level !== "off")).toBe(true);
  });

  it("uses the trimmed configured default for scripted requests", async () => {
    vi.stubEnv("PI_DEFAULT_MODEL", "  stealth/ox-alpha  ");

    await runWithModel("scripted", "scripted");

    expect(fakeAgentState.models[0]?.id).toBe("stealth/ox-alpha");
  });

  it("removes the abort listener when prompting fails", async () => {
    const controller = new AbortController();
    fakeAgentState.abortCalls = 0;
    fakeAgentState.failPrompt = true;

    await expect(runWithModel("plain-model", "test", controller.signal)).rejects.toThrow(
      "prompt failed",
    );

    controller.abort();
    expect(fakeAgentState.abortCalls).toBe(0);
  });
});