import type { Model } from "@mariozechner/pi-ai";
import { describe, expect, test } from "vitest";
import {
  defaultModelPerProvider,
  findInitialModel,
  parseModelPattern,
  resolveCliModel,
} from "../src/core/model-resolver.js";

// Mock models for testing
const mockModels: Model<"anthropic-messages">[] = [
  {
    id: "claude-sonnet-4-5",
    name: "Claude Sonnet 4.5",
    api: "anthropic-messages",
    provider: "anthropic",
    baseUrl: "https://api.anthropic.com",
    reasoning: true,
    input: ["text", "image"],
    cost: { input: 3, output: 15, cacheRead: 0.3, cacheWrite: 3.75 },
    contextWindow: 200000,
    maxTokens: 8192,
  },
  {
    id: "gpt-4o",
    name: "GPT-4o",
    api: "anthropic-messages", // Using same type for simplicity
    provider: "openai",
    baseUrl: "https://api.openai.com",
    reasoning: false,
    input: ["text", "image"],
    cost: { input: 5, output: 15, cacheRead: 0.5, cacheWrite: 5 },
    contextWindow: 128000,
    maxTokens: 4096,
  },
];

// Mock OpenRouter models with colons in IDs
const mockOpenRouterModels: Model<"anthropic-messages">[] = [
  {
    id: "qwen/qwen3-coder:exacto",
    name: "Qwen3 Coder Exacto",
    api: "anthropic-messages",
    provider: "openrouter",
    baseUrl: "https://openrouter.ai/api/v1",
    reasoning: true,
    input: ["text"],
    cost: { input: 1, output: 2, cacheRead: 0.1, cacheWrite: 1 },
    contextWindow: 128000,
    maxTokens: 8192,
  },
  {
    id: "openai/gpt-4o:extended",
    name: "GPT-4o Extended",
    api: "anthropic-messages",
    provider: "openrouter",
    baseUrl: "https://openrouter.ai/api/v1",
    reasoning: false,
    input: ["text", "image"],
    cost: { input: 5, output: 15, cacheRead: 0.5, cacheWrite: 5 },
    contextWindow: 128000,
    maxTokens: 4096,
  },
];

const allModels = [...mockModels, ...mockOpenRouterModels];

describe("parseModelPattern", () => {
  describe("simple patterns without colons", () => {
    test("exact match returns model with undefined thinking level", () => {
      const result = parseModelPattern("claude-sonnet-4-5", allModels);
      expect(result.model?.id).toBe("claude-sonnet-4-5");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toBeUndefined();
    });

    test("partial match returns best model with undefined thinking level", () => {
      const result = parseModelPattern("sonnet", allModels);
      expect(result.model?.id).toBe("claude-sonnet-4-5");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toBeUndefined();
    });

    test("no match returns undefined model and thinking level", () => {
      const result = parseModelPattern("nonexistent", allModels);
      expect(result.model).toBeUndefined();
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toBeUndefined();
    });
  });

  describe("patterns with valid thinking levels", () => {
    test("sonnet:high returns sonnet with high thinking level", () => {
      const result = parseModelPattern("sonnet:high", allModels);
      expect(result.model?.id).toBe("claude-sonnet-4-5");
      expect(result.thinkingLevel).toBe("high");
      expect(result.warning).toBeUndefined();
    });

    test("gpt-4o:medium returns gpt-4o with medium thinking level", () => {
      const result = parseModelPattern("gpt-4o:medium", allModels);
      expect(result.model?.id).toBe("gpt-4o");
      expect(result.thinkingLevel).toBe("medium");
      expect(result.warning).toBeUndefined();
    });

    test("all valid thinking levels work", () => {
      for (const level of [
        "off",
        "minimal",
        "low",
        "medium",
        "high",
        "xhigh",
      ]) {
        const result = parseModelPattern(`sonnet:${level}`, allModels);
        expect(result.model?.id).toBe("claude-sonnet-4-5");
        expect(result.thinkingLevel).toBe(level);
        expect(result.warning).toBeUndefined();
      }
    });
  });

  describe("patterns with invalid thinking levels", () => {
    test("sonnet:random returns sonnet with undefined thinking level and warning", () => {
      const result = parseModelPattern("sonnet:random", allModels);
      expect(result.model?.id).toBe("claude-sonnet-4-5");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toContain("Invalid thinking level");
      expect(result.warning).toContain("random");
    });

    test("gpt-4o:invalid returns gpt-4o with undefined thinking level and warning", () => {
      const result = parseModelPattern("gpt-4o:invalid", allModels);
      expect(result.model?.id).toBe("gpt-4o");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toContain("Invalid thinking level");
    });
  });

  describe("OpenRouter models with colons in IDs", () => {
    test("qwen3-coder:exacto matches the model with undefined thinking level", () => {
      const result = parseModelPattern("qwen/qwen3-coder:exacto", allModels);
      expect(result.model?.id).toBe("qwen/qwen3-coder:exacto");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toBeUndefined();
    });

    test("openrouter/qwen/qwen3-coder:exacto matches with provider prefix", () => {
      const result = parseModelPattern(
        "openrouter/qwen/qwen3-coder:exacto",
        allModels,
      );
      expect(result.model?.id).toBe("qwen/qwen3-coder:exacto");
      expect(result.model?.provider).toBe("openrouter");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toBeUndefined();
    });

    test("qwen3-coder:exacto:high matches model with high thinking level", () => {
      const result = parseModelPattern(
        "qwen/qwen3-coder:exacto:high",
        allModels,
      );
      expect(result.model?.id).toBe("qwen/qwen3-coder:exacto");
      expect(result.thinkingLevel).toBe("high");
      expect(result.warning).toBeUndefined();
    });

    test("openrouter/qwen/qwen3-coder:exacto:high matches with provider and thinking level", () => {
      const result = parseModelPattern(
        "openrouter/qwen/qwen3-coder:exacto:high",
        allModels,
      );
      expect(result.model?.id).toBe("qwen/qwen3-coder:exacto");
      expect(result.model?.provider).toBe("openrouter");
      expect(result.thinkingLevel).toBe("high");
      expect(result.warning).toBeUndefined();
    });

    test("gpt-4o:extended matches the extended model with undefined thinking level", () => {
      const result = parseModelPattern("openai/gpt-4o:extended", allModels);
      expect(result.model?.id).toBe("openai/gpt-4o:extended");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toBeUndefined();
    });
  });

  describe("invalid thinking levels with OpenRouter models", () => {
    test("qwen3-coder:exacto:random returns model with undefined thinking level and warning", () => {
      const result = parseModelPattern(
        "qwen/qwen3-coder:exacto:random",
        allModels,
      );
      expect(result.model?.id).toBe("qwen/qwen3-coder:exacto");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toContain("Invalid thinking level");
      expect(result.warning).toContain("random");
    });

    test("qwen3-coder:exacto:high:random returns model with undefined thinking level and warning", () => {
      const result = parseModelPattern(
        "qwen/qwen3-coder:exacto:high:random",
        allModels,
      );
      expect(result.model?.id).toBe("qwen/qwen3-coder:exacto");
      expect(result.thinkingLevel).toBeUndefined();
      expect(result.warning).toContain("Invalid thinking level");
      expect(result.warning).toContain("random");
    });
  });

  describe("edge cases", () => {
    test("empty pattern matches via partial matching", () => {
      // Empty string is included in all model IDs, so partial matching finds a match
      const result = parseModelPattern("", allModels);
      expect(result.model).not.toBeNull();
      expect(result.thinkingLevel).toBeUndefined();
    });

    test("pattern ending with colon treats empty suffix as invalid", () => {
      const result = parseModelPattern("sonnet:", allModels);
      // Empty string after colon is not a valid thinking level
      // So it tries to match "sonnet:" which won't match, then tries "sonnet"
      expect(result.model?.id).toBe("claude-sonnet-4-5");
      expect(result.warning).toContain("Invalid thinking level");
    });
  });
});

describe("resolveCliModel", () => {
  test("resolves --model provider/id without --provider", () => {
    const registry = {
      getAll: () => allModels,
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliModel: "openai/gpt-4o",
      modelRegistry: registry,
    });

    expect(result.error).toBeUndefined();
    expect(result.model?.provider).toBe("openai");
    expect(result.model?.id).toBe("gpt-4o");
  });

  test("resolves fuzzy patterns within an explicit provider", () => {
    const registry = {
      getAll: () => allModels,
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliProvider: "openai",
      cliModel: "4o",
      modelRegistry: registry,
    });

    expect(result.error).toBeUndefined();
    expect(result.model?.provider).toBe("openai");
    expect(result.model?.id).toBe("gpt-4o");
  });

  test("supports --model <pattern>:<thinking> (without explicit --thinking)", () => {
    const registry = {
      getAll: () => allModels,
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliModel: "sonnet:high",
      modelRegistry: registry,
    });

    expect(result.error).toBeUndefined();
    expect(result.model?.id).toBe("claude-sonnet-4-5");
    expect(result.thinkingLevel).toBe("high");
  });

  test("prefers exact model id match over provider inference (OpenRouter-style ids)", () => {
    const registry = {
      getAll: () => allModels,
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliModel: "openai/gpt-4o:extended",
      modelRegistry: registry,
    });

    expect(result.error).toBeUndefined();
    expect(result.model?.provider).toBe("openrouter");
    expect(result.model?.id).toBe("openai/gpt-4o:extended");
  });

  test("does not strip invalid :suffix as thinking level in --model (treat as raw id)", () => {
    const registry = {
      getAll: () => allModels,
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliProvider: "openai",
      cliModel: "gpt-4o:extended",
      modelRegistry: registry,
    });

    expect(result.error).toBeUndefined();
    expect(result.model?.provider).toBe("openai");
    expect(result.model?.id).toBe("gpt-4o:extended");
  });

  test("allows custom model ids for explicit providers without double prefixing", () => {
    const registry = {
      getAll: () => allModels,
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliProvider: "openrouter",
      cliModel: "openrouter/openai/ghost-model",
      modelRegistry: registry,
    });

    expect(result.error).toBeUndefined();
    expect(result.model?.provider).toBe("openrouter");
    expect(result.model?.id).toBe("openai/ghost-model");
  });

  test("returns a clear error when there are no models", () => {
    const registry = {
      getAll: () => [],
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliProvider: "openai",
      cliModel: "gpt-4o",
      modelRegistry: registry,
    });

    expect(result.model).toBeUndefined();
    expect(result.error).toContain("No models available");
  });

  test("prefers provider/model split over gateway model with matching id", () => {
    // When a user writes "zai/glm-5", and both a zai provider model (id: "glm-5")
    // and a gateway model (id: "zai/glm-5") exist, prefer the zai provider model.
    const zaiModel: Model<"anthropic-messages"> = {
      id: "glm-5",
      name: "GLM-5",
      api: "anthropic-messages",
      provider: "zai",
      baseUrl: "https://open.bigmodel.cn/api/paas/v4",
      reasoning: true,
      input: ["text"],
      cost: { input: 1, output: 2, cacheRead: 0.1, cacheWrite: 1 },
      contextWindow: 128000,
      maxTokens: 8192,
    };
    const gatewayModel: Model<"anthropic-messages"> = {
      id: "zai/glm-5",
      name: "GLM-5",
      api: "anthropic-messages",
      provider: "vercel-ai-gateway",
      baseUrl: "https://ai-gateway.vercel.sh",
      reasoning: true,
      input: ["text"],
      cost: { input: 1, output: 2, cacheRead: 0.1, cacheWrite: 1 },
      contextWindow: 128000,
      maxTokens: 8192,
    };
    const registry = {
      getAll: () => [...allModels, zaiModel, gatewayModel],
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliModel: "zai/glm-5",
      modelRegistry: registry,
    });

    expect(result.error).toBeUndefined();
    expect(result.model?.provider).toBe("zai");
    expect(result.model?.id).toBe("glm-5");
  });

  test("resolves provider-prefixed fuzzy patterns (openrouter/qwen -> openrouter model)", () => {
    const registry = {
      getAll: () => allModels,
    } as unknown as Parameters<typeof resolveCliModel>[0]["modelRegistry"];

    const result = resolveCliModel({
      cliModel: "openrouter/qwen",
      modelRegistry: registry,
    });

    expect(result.error).toBeUndefined();
    expect(result.model?.provider).toBe("openrouter");
    expect(result.model?.id).toBe("qwen/qwen3-coder:exacto");
  });
});

describe("default model selection", () => {
  test("openai defaults are gpt-5.4", () => {
    expect(defaultModelPerProvider.openai).toBe("gpt-5.4");
    expect(defaultModelPerProvider["openai-codex"]).toBe("gpt-5.4");
  });

  test("ai-gateway default is opus 4.6", () => {
    expect(defaultModelPerProvider["vercel-ai-gateway"]).toBe(
      "anthropic/claude-opus-4-6",
    );
  });

  test("findInitialModel accepts explicit provider custom model ids", async () => {
    const registry = {
      getAll: () => allModels,
    } as unknown as Parameters<typeof findInitialModel>[0]["modelRegistry"];

    const result = await findInitialModel({
      cliProvider: "openrouter",
      cliModel: "openrouter/openai/ghost-model",
      scopedModels: [],
      isContinuing: false,
      modelRegistry: registry,
    });

    expect(result.model?.provider).toBe("openrouter");
    expect(result.model?.id).toBe("openai/ghost-model");
  });

  test("findInitialModel selects ai-gateway default when available", async () => {
    const aiGatewayModel: Model<"anthropic-messages"> = {
      id: "anthropic/claude-opus-4-6",
      name: "Claude Opus 4.6",
      api: "anthropic-messages",
      provider: "vercel-ai-gateway",
      baseUrl: "https://ai-gateway.vercel.sh",
      reasoning: true,
      input: ["text", "image"],
      cost: { input: 5, output: 15, cacheRead: 0.5, cacheWrite: 5 },
      contextWindow: 200000,
      maxTokens: 8192,
    };

    const registry = {
      getAvailable: async () => [aiGatewayModel],
    } as unknown as Parameters<typeof findInitialModel>[0]["modelRegistry"];

    const result = await findInitialModel({
      scopedModels: [],
      isContinuing: false,
      modelRegistry: registry,
    });

    expect(result.model?.provider).toBe("vercel-ai-gateway");
    expect(result.model?.id).toBe("anthropic/claude-opus-4-6");
  });
});
