import { AnthropicBackend } from "../backends/anthropic.js";
import { ChatCompletionResponse } from "../backends/llm-base.js";

describe("AnthropicBackend", () => {
  const originalFetch = globalThis.fetch;
  let fetchCalls: Array<{ url: string; headers: Record<string, string>; body: string }>;

  beforeEach(() => {
    fetchCalls = [];
  });

  afterEach(() => {
    globalThis.fetch = originalFetch;
    delete process.env.TEST_ANTHROPIC_KEY;
    delete process.env.TEST_ANTHROPIC_KEY_EMPTY;
  });

  function mockFetch(response: Record<string, unknown>, status = 200): void {
    globalThis.fetch = ((url: string, init: RequestInit) => {
      fetchCalls.push({
        url,
        headers: (init.headers as Record<string, string>) || {},
        body: init.body as string,
      });
      return Promise.resolve({
        ok: status >= 200 && status < 300,
        status,
        text: () => Promise.resolve(JSON.stringify(response)),
        json: () => Promise.resolve(response),
      } as Response);
    }) as typeof fetch;
  }

  function makeAnthropicResponse(text: string, usage = { input_tokens: 10, output_tokens: 20 }): Record<string, unknown> {
    return {
      content: [{ type: "text", text }],
      usage,
      model: "claude-sonnet-4-20250514",
    };
  }

  describe("isAvailable", () => {
    it("returns true when API key is present", async () => {
      process.env.TEST_ANTHROPIC_KEY = "sk-ant-test-key-123";
      const backend = new AnthropicBackend({
        base_url: "https://api.anthropic.com",
        api_key_env: "TEST_ANTHROPIC_KEY",
        model: "claude-sonnet-4-20250514",
        model_profile: "quality",
      });
      expect(await backend.isAvailable()).toBe(true);
    });

    it("returns false when API key is absent", async () => {
      const backend = new AnthropicBackend({
        base_url: "https://api.anthropic.com",
        api_key_env: "NONEXISTENT_ANTHROPIC_KEY_VAR_99999",
        model: "claude-sonnet-4-20250514",
        model_profile: "quality",
      });
      expect(await backend.isAvailable()).toBe(false);
    });
  });

  describe("resolveModel", () => {
    it("returns config.model when set", async () => {
      process.env.TEST_ANTHROPIC_KEY = "sk-ant-test";
      mockFetch(makeAnthropicResponse('{"success": true, "output": "done"}'));
      const backend = new AnthropicBackend({
        base_url: "https://api.anthropic.com",
        api_key_env: "TEST_ANTHROPIC_KEY",
        model: "claude-3-haiku-20240307",
        model_profile: "speed",
      });
      const request = {
        persona: "executor" as const,
        workflow: "execute",
        task: "test",
        context: {
          project_path: "/tmp",
          phase: 1,
          stage: "execute" as const,
          specification: "",
          config_path: "",
        },
        autonomy: "full" as const,
      };
      await backend.execute(request);
      const body = JSON.parse(fetchCalls[0].body);
      expect(body.model).toBe("claude-3-haiku-20240307");
    });

    it("defaults to claude-sonnet-4-20250514 when model not specified", async () => {
      process.env.TEST_ANTHROPIC_KEY = "sk-ant-test";
      mockFetch(makeAnthropicResponse('{"success": true, "output": "done"}'));
      const backend = new AnthropicBackend({
        base_url: "https://api.anthropic.com",
        api_key_env: "TEST_ANTHROPIC_KEY",
        model: "",
        model_profile: "quality",
      });
      const request = {
        persona: "executor" as const,
        workflow: "execute",
        task: "test",
        context: {
          project_path: "/tmp",
          phase: 1,
          stage: "execute" as const,
          specification: "",
          config_path: "",
        },
        autonomy: "full" as const,
      };
      await backend.execute(request);
      const body = JSON.parse(fetchCalls[0].body);
      expect(body.model).toBe("claude-sonnet-4-20250514");
    });
  });

  describe("callModel request format", () => {
    it("sends correct URL, x-api-key header, anthropic-version header, system field, max_tokens", async () => {
      process.env.TEST_ANTHROPIC_KEY = "sk-ant-test-key-abc";
      mockFetch(makeAnthropicResponse('{"success": true, "output": "done"}'));

      const backend = new AnthropicBackend({
        base_url: "https://api.anthropic.com",
        api_key_env: "TEST_ANTHROPIC_KEY",
        model: "claude-sonnet-4-20250514",
        model_profile: "quality",
      });

      const request = {
        persona: "executor" as const,
        workflow: "execute",
        task: "Do the thing",
        context: {
          project_path: "/tmp",
          phase: 1,
          stage: "execute" as const,
          specification: "",
          config_path: "",
        },
        autonomy: "full" as const,
      };

      await backend.execute(request);

      expect(fetchCalls.length).toBe(1);
      expect(fetchCalls[0].url).toBe("https://api.anthropic.com/v1/messages");
      expect(fetchCalls[0].headers["x-api-key"]).toBe("sk-ant-test-key-abc");
      expect(fetchCalls[0].headers["anthropic-version"]).toBe("2023-06-01");
      expect(fetchCalls[0].headers["Content-Type"]).toBe("application/json");
      expect(fetchCalls[0].headers["Authorization"]).toBeUndefined();

      const body = JSON.parse(fetchCalls[0].body);
      expect(body.model).toBe("claude-sonnet-4-20250514");
      expect(body.max_tokens).toBe(4096);
      expect(typeof body.system).toBe("string");
      expect(body.system.length).toBeGreaterThan(0);
      expect(Array.isArray(body.messages)).toBe(true);
      expect(body.messages.length).toBeGreaterThanOrEqual(1);
    });
  });

  describe("custom base_url override", () => {
    it("sends request to custom base_url", async () => {
      process.env.TEST_ANTHROPIC_KEY = "sk-ant-test";
      mockFetch(makeAnthropicResponse('{"success": true, "output": "done"}'));

      const backend = new AnthropicBackend({
        base_url: "https://custom-proxy.example.com/api",
        api_key_env: "TEST_ANTHROPIC_KEY",
        model: "claude-sonnet-4-20250514",
        model_profile: "quality",
      });

      const request = {
        persona: "executor" as const,
        workflow: "execute",
        task: "test",
        context: {
          project_path: "/tmp",
          phase: 1,
          stage: "execute" as const,
          specification: "",
          config_path: "",
        },
        autonomy: "full" as const,
      };

      await backend.execute(request);
      expect(fetchCalls[0].url).toBe("https://custom-proxy.example.com/api/v1/messages");
    });
  });
});