import { describe, it, expect, vi, beforeEach } from "vitest";
import { AgentService } from "@/services/agent-service.js";
import { ProviderFactory } from "@/providers/provider-factory.js";
import * as fs from "fs/promises";
import * as imageHandler from "@/lib/image-handler.js";
import * as promptBuilder from "@/lib/prompt-builder.js";
import { collectAsyncGenerator } from "../../utils/helpers.js";

vi.mock("fs/promises");
vi.mock("@/providers/provider-factory.js");
vi.mock("@/lib/image-handler.js");
vi.mock("@/lib/prompt-builder.js");

describe("agent-service.ts", () => {
  let service: AgentService;
  const mockEvents = {
    subscribe: vi.fn(),
    emit: vi.fn(),
  };

  beforeEach(() => {
    vi.clearAllMocks();
    service = new AgentService("/test/data", mockEvents as any);
  });

  describe("initialize", () => {
    it("should create state directory", async () => {
      vi.mocked(fs.mkdir).mockResolvedValue(undefined);

      await service.initialize();

      expect(fs.mkdir).toHaveBeenCalledWith(
        expect.stringContaining("agent-sessions"),
        { recursive: true }
      );
    });
  });

  describe("startConversation", () => {
    it("should create new session with empty messages", async () => {
      const error: any = new Error("ENOENT");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);

      const result = await service.startConversation({
        sessionId: "session-1",
        workingDirectory: "/test/dir",
      });

      expect(result.success).toBe(true);
      expect(result.messages).toEqual([]);
      expect(result.sessionId).toBe("session-1");
    });

    it("should load existing session", async () => {
      const existingMessages = [
        {
          id: "msg-1",
          role: "user",
          content: "Hello",
          timestamp: "2024-01-01T00:00:00Z",
        },
      ];

      vi.mocked(fs.readFile).mockResolvedValue(
        JSON.stringify(existingMessages)
      );

      const result = await service.startConversation({
        sessionId: "session-1",
        workingDirectory: "/test/dir",
      });

      expect(result.success).toBe(true);
      expect(result.messages).toEqual(existingMessages);
    });

    it("should use process.cwd() if no working directory provided", async () => {
      const error: any = new Error("ENOENT");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);

      const result = await service.startConversation({
        sessionId: "session-1",
      });

      expect(result.success).toBe(true);
    });

    it("should reuse existing session if already started", async () => {
      const error: any = new Error("ENOENT");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);

      // Start session first time
      await service.startConversation({
        sessionId: "session-1",
      });

      // Start again with same ID
      const result = await service.startConversation({
        sessionId: "session-1",
      });

      expect(result.success).toBe(true);
      // First call reads session file and metadata file (2 calls)
      // Second call should reuse in-memory session (no additional calls)
      expect(fs.readFile).toHaveBeenCalledTimes(2);
    });
  });

  describe("sendMessage", () => {
    beforeEach(async () => {
      const error: any = new Error("ENOENT");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);
      vi.mocked(fs.writeFile).mockResolvedValue(undefined);
      vi.mocked(fs.mkdir).mockResolvedValue(undefined);

      await service.startConversation({
        sessionId: "session-1",
        workingDirectory: "/test/dir",
      });
    });

    it("should throw if session not found", async () => {
      await expect(
        service.sendMessage({
          sessionId: "nonexistent",
          message: "Hello",
        })
      ).rejects.toThrow("Session nonexistent not found");
    });


    it("should process message and stream responses", async () => {
      const mockProvider = {
        getName: () => "claude",
        executeQuery: async function* () {
          yield {
            type: "assistant",
            message: {
              role: "assistant",
              content: [{ type: "text", text: "Response" }],
            },
          };
          yield {
            type: "result",
            subtype: "success",
          };
        },
      };

      vi.mocked(ProviderFactory.getProviderForModel).mockReturnValue(
        mockProvider as any
      );

      vi.mocked(promptBuilder.buildPromptWithImages).mockResolvedValue({
        content: "Hello",
        hasImages: false,
      });

      const result = await service.sendMessage({
        sessionId: "session-1",
        message: "Hello",
        workingDirectory: "/custom/dir",
      });

      expect(result.success).toBe(true);
      expect(mockEvents.emit).toHaveBeenCalled();
    });

    it("should handle images in message", async () => {
      const mockProvider = {
        getName: () => "claude",
        executeQuery: async function* () {
          yield {
            type: "result",
            subtype: "success",
          };
        },
      };

      vi.mocked(ProviderFactory.getProviderForModel).mockReturnValue(
        mockProvider as any
      );

      vi.mocked(imageHandler.readImageAsBase64).mockResolvedValue({
        base64: "base64data",
        mimeType: "image/png",
        filename: "test.png",
        originalPath: "/path/test.png",
      });

      vi.mocked(promptBuilder.buildPromptWithImages).mockResolvedValue({
        content: "Check image",
        hasImages: true,
      });

      await service.sendMessage({
        sessionId: "session-1",
        message: "Check this",
        imagePaths: ["/path/test.png"],
      });

      expect(imageHandler.readImageAsBase64).toHaveBeenCalledWith(
        "/path/test.png"
      );
    });

    it("should handle failed image loading gracefully", async () => {
      const mockProvider = {
        getName: () => "claude",
        executeQuery: async function* () {
          yield {
            type: "result",
            subtype: "success",
          };
        },
      };

      vi.mocked(ProviderFactory.getProviderForModel).mockReturnValue(
        mockProvider as any
      );

      vi.mocked(imageHandler.readImageAsBase64).mockRejectedValue(
        new Error("Image not found")
      );

      vi.mocked(promptBuilder.buildPromptWithImages).mockResolvedValue({
        content: "Check image",
        hasImages: false,
      });

      const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});

      await service.sendMessage({
        sessionId: "session-1",
        message: "Check this",
        imagePaths: ["/path/test.png"],
      });

      expect(consoleSpy).toHaveBeenCalled();
      consoleSpy.mockRestore();
    });

    it("should use custom model if provided", async () => {
      const mockProvider = {
        getName: () => "claude",
        executeQuery: async function* () {
          yield {
            type: "result",
            subtype: "success",
          };
        },
      };

      vi.mocked(ProviderFactory.getProviderForModel).mockReturnValue(
        mockProvider as any
      );

      vi.mocked(promptBuilder.buildPromptWithImages).mockResolvedValue({
        content: "Hello",
        hasImages: false,
      });

      await service.sendMessage({
        sessionId: "session-1",
        message: "Hello",
        model: "claude-sonnet-4-20250514",
      });

      expect(ProviderFactory.getProviderForModel).toHaveBeenCalledWith("claude-sonnet-4-20250514");
    });

    it("should save session messages", async () => {
      const mockProvider = {
        getName: () => "claude",
        executeQuery: async function* () {
          yield {
            type: "result",
            subtype: "success",
          };
        },
      };

      vi.mocked(ProviderFactory.getProviderForModel).mockReturnValue(
        mockProvider as any
      );

      vi.mocked(promptBuilder.buildPromptWithImages).mockResolvedValue({
        content: "Hello",
        hasImages: false,
      });

      await service.sendMessage({
        sessionId: "session-1",
        message: "Hello",
      });

      expect(fs.writeFile).toHaveBeenCalled();
    });
  });

  describe("stopExecution", () => {
    it("should stop execution for a session", async () => {
      const error: any = new Error("ENOENT");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);

      await service.startConversation({
        sessionId: "session-1",
      });

      // Should return success
      const result = await service.stopExecution("session-1");
      expect(result.success).toBeDefined();
    });
  });

  describe("getHistory", () => {
    it("should return message history", async () => {
      const error: any = new Error("ENOENT");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);

      await service.startConversation({
        sessionId: "session-1",
      });

      const history = service.getHistory("session-1");

      expect(history).toBeDefined();
      expect(history?.messages).toEqual([]);
    });

    it("should handle non-existent session", () => {
      const history = service.getHistory("nonexistent");
      expect(history).toBeDefined(); // Returns error object
    });
  });

  describe("clearSession", () => {
    it("should clear session messages", async () => {
      const error: any = new Error("ENOENT");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);
      vi.mocked(fs.writeFile).mockResolvedValue(undefined);
      vi.mocked(fs.mkdir).mockResolvedValue(undefined);

      await service.startConversation({
        sessionId: "session-1",
      });

      await service.clearSession("session-1");

      const history = service.getHistory("session-1");
      expect(history?.messages).toEqual([]);
      expect(fs.writeFile).toHaveBeenCalled();
    });
  });
});