import { describe, it, expect, vi, beforeEach } from "vitest";
import { FeatureLoader } from "@/services/feature-loader.js";
import * as fs from "fs/promises";
import path from "path";

vi.mock("fs/promises");

describe("feature-loader.ts", () => {
  let loader: FeatureLoader;
  const testProjectPath = "/test/project";

  beforeEach(() => {
    vi.clearAllMocks();
    loader = new FeatureLoader();
  });

  describe("getFeaturesDir", () => {
    it("should return features directory path", () => {
      const result = loader.getFeaturesDir(testProjectPath);
      expect(result).toContain("test");
      expect(result).toContain("project");
      expect(result).toContain(".automaker");
      expect(result).toContain("features");
    });
  });

  describe("getFeatureImagesDir", () => {
    it("should return feature images directory path", () => {
      const result = loader.getFeatureImagesDir(testProjectPath, "feature-123");
      expect(result).toContain("features");
      expect(result).toContain("feature-123");
      expect(result).toContain("images");
    });
  });

  describe("getFeatureDir", () => {
    it("should return feature directory path", () => {
      const result = loader.getFeatureDir(testProjectPath, "feature-123");
      expect(result).toContain("features");
      expect(result).toContain("feature-123");
    });
  });

  describe("getFeatureJsonPath", () => {
    it("should return feature.json path", () => {
      const result = loader.getFeatureJsonPath(testProjectPath, "feature-123");
      expect(result).toContain("features");
      expect(result).toContain("feature-123");
      expect(result).toContain("feature.json");
    });
  });

  describe("getAgentOutputPath", () => {
    it("should return agent-output.md path", () => {
      const result = loader.getAgentOutputPath(testProjectPath, "feature-123");
      expect(result).toContain("features");
      expect(result).toContain("feature-123");
      expect(result).toContain("agent-output.md");
    });
  });

  describe("generateFeatureId", () => {
    it("should generate unique feature ID with timestamp", () => {
      const id1 = loader.generateFeatureId();
      const id2 = loader.generateFeatureId();

      expect(id1).toMatch(/^feature-\d+-[a-z0-9]+$/);
      expect(id2).toMatch(/^feature-\d+-[a-z0-9]+$/);
      expect(id1).not.toBe(id2);
    });

    it("should start with 'feature-'", () => {
      const id = loader.generateFeatureId();
      expect(id).toMatch(/^feature-/);
    });
  });

  describe("getAll", () => {
    it("should return empty array when features directory doesn't exist", async () => {
      vi.mocked(fs.access).mockRejectedValue(new Error("ENOENT"));

      const result = await loader.getAll(testProjectPath);

      expect(result).toEqual([]);
    });

    it("should load all features from feature directories", async () => {
      vi.mocked(fs.access).mockResolvedValue(undefined);
      vi.mocked(fs.readdir).mockResolvedValue([
        { name: "feature-1", isDirectory: () => true } as any,
        { name: "feature-2", isDirectory: () => true } as any,
        { name: "file.txt", isDirectory: () => false } as any,
      ]);

      vi.mocked(fs.readFile)
        .mockResolvedValueOnce(
          JSON.stringify({
            id: "feature-1",
            category: "ui",
            description: "Feature 1",
          })
        )
        .mockResolvedValueOnce(
          JSON.stringify({
            id: "feature-2",
            category: "backend",
            description: "Feature 2",
          })
        );

      const result = await loader.getAll(testProjectPath);

      expect(result).toHaveLength(2);
      expect(result[0].id).toBe("feature-1");
      expect(result[1].id).toBe("feature-2");
    });

    it("should skip features without id field", async () => {
      vi.mocked(fs.access).mockResolvedValue(undefined);
      vi.mocked(fs.readdir).mockResolvedValue([
        { name: "feature-1", isDirectory: () => true } as any,
        { name: "feature-2", isDirectory: () => true } as any,
      ]);

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

      vi.mocked(fs.readFile)
        .mockResolvedValueOnce(
          JSON.stringify({
            category: "ui",
            description: "Missing ID",
          })
        )
        .mockResolvedValueOnce(
          JSON.stringify({
            id: "feature-2",
            category: "backend",
            description: "Feature 2",
          })
        );

      const result = await loader.getAll(testProjectPath);

      expect(result).toHaveLength(1);
      expect(result[0].id).toBe("feature-2");
      expect(consoleSpy).toHaveBeenCalledWith(
        "[FeatureLoader]",
        expect.stringContaining("missing required 'id' field")
      );

      consoleSpy.mockRestore();
    });

    it("should skip features with missing feature.json", async () => {
      vi.mocked(fs.access).mockResolvedValue(undefined);
      vi.mocked(fs.readdir).mockResolvedValue([
        { name: "feature-1", isDirectory: () => true } as any,
        { name: "feature-2", isDirectory: () => true } as any,
      ]);

      const error: any = new Error("File not found");
      error.code = "ENOENT";

      vi.mocked(fs.readFile)
        .mockRejectedValueOnce(error)
        .mockResolvedValueOnce(
          JSON.stringify({
            id: "feature-2",
            category: "backend",
            description: "Feature 2",
          })
        );

      const result = await loader.getAll(testProjectPath);

      expect(result).toHaveLength(1);
      expect(result[0].id).toBe("feature-2");
    });

    it("should handle malformed JSON gracefully", async () => {
      vi.mocked(fs.access).mockResolvedValue(undefined);
      vi.mocked(fs.readdir).mockResolvedValue([
        { name: "feature-1", isDirectory: () => true } as any,
      ]);

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

      vi.mocked(fs.readFile).mockResolvedValue("invalid json{");

      const result = await loader.getAll(testProjectPath);

      expect(result).toEqual([]);
      expect(consoleSpy).toHaveBeenCalledWith(
        "[FeatureLoader]",
        expect.stringContaining("Failed to parse feature.json")
      );

      consoleSpy.mockRestore();
    });

    it("should sort features by creation order (timestamp)", async () => {
      vi.mocked(fs.access).mockResolvedValue(undefined);
      vi.mocked(fs.readdir).mockResolvedValue([
        { name: "feature-3", isDirectory: () => true } as any,
        { name: "feature-1", isDirectory: () => true } as any,
        { name: "feature-2", isDirectory: () => true } as any,
      ]);

      vi.mocked(fs.readFile)
        .mockResolvedValueOnce(
          JSON.stringify({
            id: "feature-3000-xyz",
            category: "ui",
          })
        )
        .mockResolvedValueOnce(
          JSON.stringify({
            id: "feature-1000-abc",
            category: "ui",
          })
        )
        .mockResolvedValueOnce(
          JSON.stringify({
            id: "feature-2000-def",
            category: "ui",
          })
        );

      const result = await loader.getAll(testProjectPath);

      expect(result).toHaveLength(3);
      expect(result[0].id).toBe("feature-1000-abc");
      expect(result[1].id).toBe("feature-2000-def");
      expect(result[2].id).toBe("feature-3000-xyz");
    });
  });

  describe("get", () => {
    it("should return feature by ID", async () => {
      const featureData = {
        id: "feature-123",
        category: "ui",
        description: "Test feature",
      };

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

      const result = await loader.get(testProjectPath, "feature-123");

      expect(result).toEqual(featureData);
    });

    it("should return null when feature doesn't exist", async () => {
      const error: any = new Error("File not found");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);

      const result = await loader.get(testProjectPath, "feature-123");

      expect(result).toBeNull();
    });

    it("should throw on other errors", async () => {
      vi.mocked(fs.readFile).mockRejectedValue(new Error("Permission denied"));

      await expect(
        loader.get(testProjectPath, "feature-123")
      ).rejects.toThrow("Permission denied");
    });
  });

  describe("create", () => {
    it("should create new feature", async () => {
      vi.mocked(fs.mkdir).mockResolvedValue(undefined);
      vi.mocked(fs.writeFile).mockResolvedValue(undefined);

      const featureData = {
        category: "ui",
        description: "New feature",
      };

      const result = await loader.create(testProjectPath, featureData);

      expect(result).toMatchObject({
        category: "ui",
        description: "New feature",
        id: expect.stringMatching(/^feature-/),
      });
      expect(fs.writeFile).toHaveBeenCalled();
    });

    it("should use provided ID if given", async () => {
      vi.mocked(fs.mkdir).mockResolvedValue(undefined);
      vi.mocked(fs.writeFile).mockResolvedValue(undefined);

      const result = await loader.create(testProjectPath, {
        id: "custom-id",
        category: "ui",
        description: "Test",
      });

      expect(result.id).toBe("custom-id");
    });

    it("should set default category if not provided", async () => {
      vi.mocked(fs.mkdir).mockResolvedValue(undefined);
      vi.mocked(fs.writeFile).mockResolvedValue(undefined);

      const result = await loader.create(testProjectPath, {
        description: "Test",
      });

      expect(result.category).toBe("Uncategorized");
    });
  });

  describe("update", () => {
    it("should update existing feature", async () => {
      vi.mocked(fs.readFile).mockResolvedValue(
        JSON.stringify({
          id: "feature-123",
          category: "ui",
          description: "Old description",
        })
      );
      vi.mocked(fs.writeFile).mockResolvedValue(undefined);

      const result = await loader.update(testProjectPath, "feature-123", {
        description: "New description",
      });

      expect(result.description).toBe("New description");
      expect(result.category).toBe("ui");
      expect(fs.writeFile).toHaveBeenCalled();
    });

    it("should throw if feature doesn't exist", async () => {
      const error: any = new Error("File not found");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);

      await expect(
        loader.update(testProjectPath, "feature-123", {})
      ).rejects.toThrow("not found");
    });
  });

  describe("delete", () => {
    it("should delete feature directory", async () => {
      vi.mocked(fs.rm).mockResolvedValue(undefined);

      const result = await loader.delete(testProjectPath, "feature-123");

      expect(result).toBe(true);
      expect(fs.rm).toHaveBeenCalledWith(
        expect.stringContaining("feature-123"),
        { recursive: true, force: true }
      );
    });

    it("should return false on error", async () => {
      vi.mocked(fs.rm).mockRejectedValue(new Error("Permission denied"));

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

      const result = await loader.delete(testProjectPath, "feature-123");

      expect(result).toBe(false);
      expect(consoleSpy).toHaveBeenCalledWith(
        "[FeatureLoader]",
        expect.stringContaining("Failed to delete feature"),
        expect.objectContaining({ message: "Permission denied" })
      );
      consoleSpy.mockRestore();
    });
  });

  describe("getAgentOutput", () => {
    it("should return agent output content", async () => {
      vi.mocked(fs.readFile).mockResolvedValue("Agent output content");

      const result = await loader.getAgentOutput(testProjectPath, "feature-123");

      expect(result).toBe("Agent output content");
    });

    it("should return null when file doesn't exist", async () => {
      const error: any = new Error("File not found");
      error.code = "ENOENT";
      vi.mocked(fs.readFile).mockRejectedValue(error);

      const result = await loader.getAgentOutput(testProjectPath, "feature-123");

      expect(result).toBeNull();
    });

    it("should throw on other errors", async () => {
      vi.mocked(fs.readFile).mockRejectedValue(new Error("Permission denied"));

      await expect(
        loader.getAgentOutput(testProjectPath, "feature-123")
      ).rejects.toThrow("Permission denied");
    });
  });

  describe("saveAgentOutput", () => {
    it("should save agent output to file", async () => {
      vi.mocked(fs.mkdir).mockResolvedValue(undefined);
      vi.mocked(fs.writeFile).mockResolvedValue(undefined);

      await loader.saveAgentOutput(
        testProjectPath,
        "feature-123",
        "Output content"
      );

      expect(fs.writeFile).toHaveBeenCalledWith(
        expect.stringContaining("agent-output.md"),
        "Output content",
        "utf-8"
      );
    });
  });

  describe("deleteAgentOutput", () => {
    it("should delete agent output file", async () => {
      vi.mocked(fs.unlink).mockResolvedValue(undefined);

      await loader.deleteAgentOutput(testProjectPath, "feature-123");

      expect(fs.unlink).toHaveBeenCalledWith(
        expect.stringContaining("agent-output.md")
      );
    });

    it("should handle missing file gracefully", async () => {
      const error: any = new Error("File not found");
      error.code = "ENOENT";
      vi.mocked(fs.unlink).mockRejectedValue(error);

      // Should not throw
      await expect(
        loader.deleteAgentOutput(testProjectPath, "feature-123")
      ).resolves.toBeUndefined();
    });

    it("should throw on other errors", async () => {
      vi.mocked(fs.unlink).mockRejectedValue(new Error("Permission denied"));

      await expect(
        loader.deleteAgentOutput(testProjectPath, "feature-123")
      ).rejects.toThrow("Permission denied");
    });
  });
});