// frontend/tests/api.test.js

// Import the function to test (adjust path if your structure is different)
// We might need to configure Jest or use Babel for ES module syntax if this causes issues.
import { getSpeakers, addSpeaker, deleteSpeaker, generateDialog } from '../js/api.js';

// Mock the global fetch function
global.fetch = jest.fn();

const API_BASE_URL = 'http://localhost:8000/api'; // Centralize for all tests

describe('API Client - getSpeakers', () => {
    beforeEach(() => {
        // Clear all instances and calls to constructor and all methods:
        fetch.mockClear();
    });

    it('should fetch speakers successfully', async () => {
        const mockSpeakers = [{ id: '1', name: 'Speaker 1' }, { id: '2', name: 'Speaker 2' }];
        fetch.mockResolvedValueOnce({
            ok: true,
            json: async () => mockSpeakers,
        });

        const speakers = await getSpeakers();
        expect(fetch).toHaveBeenCalledTimes(1);
        expect(fetch).toHaveBeenCalledWith(`${API_BASE_URL}/speakers`);
        expect(speakers).toEqual(mockSpeakers);
    });

    it('should throw an error if the network response is not ok', async () => {
        fetch.mockResolvedValueOnce({
            ok: false,
            statusText: 'Not Found',
            json: async () => ({ detail: 'Speakers not found' }) // Simulate FastAPI error response
        });

        await expect(getSpeakers()).rejects.toThrow('Failed to fetch speakers: Speakers not found');
        expect(fetch).toHaveBeenCalledTimes(1);
    });

    it('should throw a generic error if parsing error response fails', async () => {
        fetch.mockResolvedValueOnce({
            ok: false,
            statusText: 'Internal Server Error',
            json: async () => { throw new Error('Failed to parse error JSON'); } // Simulate error during .json()
        });

        await expect(getSpeakers()).rejects.toThrow('Failed to fetch speakers: Internal Server Error');
        expect(fetch).toHaveBeenCalledTimes(1);
    });
    
    it('should throw an error if fetch itself fails (network error)', async () => {
        fetch.mockRejectedValueOnce(new TypeError('Network failed'));

        await expect(getSpeakers()).rejects.toThrow('Network failed'); // This will be the original fetch error
        expect(fetch).toHaveBeenCalledTimes(1);
    });
});

describe('API Client - addSpeaker', () => {
    beforeEach(() => {
        fetch.mockClear();
    });

    it('should add a speaker successfully', async () => {
        const mockFormData = new FormData(); // In a real scenario, this would have data
        mockFormData.append('name', 'Test Speaker');
        // mockFormData.append('audio_sample_file', new File([''], 'sample.wav')); // File creation in Node test needs more setup or a mock

        const mockResponse = { id: '3', name: 'Test Speaker', message: 'Speaker added successfully' };
        fetch.mockResolvedValueOnce({
            ok: true,
            json: async () => mockResponse,
        });

        const result = await addSpeaker(mockFormData);
        expect(fetch).toHaveBeenCalledTimes(1);
        expect(fetch).toHaveBeenCalledWith(`${API_BASE_URL}/speakers`, {
            method: 'POST',
            body: mockFormData,
        });
        expect(result).toEqual(mockResponse);
    });

    it('should throw an error if adding a speaker fails', async () => {
        const mockFormData = new FormData();
        fetch.mockResolvedValueOnce({
            ok: false,
            statusText: 'Bad Request',
            json: async () => ({ detail: 'Invalid speaker data' }),
        });

        await expect(addSpeaker(mockFormData)).rejects.toThrow('Failed to add speaker: Invalid speaker data');
        expect(fetch).toHaveBeenCalledTimes(1);
    });
});

describe('API Client - deleteSpeaker', () => {
    beforeEach(() => {
        fetch.mockClear();
    });

    it('should delete a speaker successfully with JSON response', async () => {
        const speakerId = 'test-speaker-id-123';
        const mockResponse = { message: `Speaker ${speakerId} deleted successfully` };
        fetch.mockResolvedValueOnce({
            ok: true,
            status: 200, // Or any 2xx status that might return JSON
            json: async () => mockResponse,
        });

        const result = await deleteSpeaker(speakerId);
        expect(fetch).toHaveBeenCalledTimes(1);
        expect(fetch).toHaveBeenCalledWith(`${API_BASE_URL}/speakers/${speakerId}`, {
            method: 'DELETE',
        });
        expect(result).toEqual(mockResponse);
    });

    it('should handle successful deletion with 204 No Content response', async () => {
        const speakerId = 'test-speaker-id-204';
        fetch.mockResolvedValueOnce({
            ok: true,
            status: 204,
            statusText: 'No Content',
            // .json() is not called by the function if status is 204
        });

        const result = await deleteSpeaker(speakerId);
        expect(fetch).toHaveBeenCalledTimes(1);
        expect(fetch).toHaveBeenCalledWith(`${API_BASE_URL}/speakers/${speakerId}`, {
            method: 'DELETE',
        });
        expect(result).toEqual({ message: `Speaker ${speakerId} deleted successfully.` });
    });

    it('should throw an error if deleting a speaker fails (e.g., speaker not found)', async () => {
        const speakerId = 'non-existent-speaker-id';
        fetch.mockResolvedValueOnce({
            ok: false,
            status: 404,
            statusText: 'Not Found',
            json: async () => ({ detail: 'Speaker not found' }),
        });

        await expect(deleteSpeaker(speakerId)).rejects.toThrow(`Failed to delete speaker ${speakerId}: Speaker not found`);
        expect(fetch).toHaveBeenCalledTimes(1);
    });
});

describe('API Client - generateDialog', () => {
    beforeEach(() => {
        fetch.mockClear();
    });

    it('should generate dialog successfully', async () => {
        const mockPayload = {
            output_base_name: "test_dialog",
            dialog_items: [
                { type: "speech", speaker_id: "spk_1", text: "Hello.", exaggeration: 1.0, cfg_weight: 3.0, temperature: 0.5 },
                { type: "silence", duration_ms: 250 }
            ]
        };
        const mockResponse = {
            log: "Dialog generated.",
            concatenated_audio_url: "/audio/test_dialog_concatenated.wav",
            zip_archive_url: "/audio/test_dialog.zip"
        };
        fetch.mockResolvedValueOnce({
            ok: true,
            json: async () => mockResponse,
        });

        const result = await generateDialog(mockPayload);
        expect(fetch).toHaveBeenCalledTimes(1);
        expect(fetch).toHaveBeenCalledWith(`${API_BASE_URL}/dialog/generate`, {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify(mockPayload),
        });
        expect(result).toEqual(mockResponse);
    });

    it('should throw an error if dialog generation fails', async () => {
        const mockPayload = { output_base_name: "fail_dialog", dialog_items: [] }; // Example invalid payload
        fetch.mockResolvedValueOnce({
            ok: false,
            statusText: 'Bad Request',
            json: async () => ({ detail: 'Invalid dialog data' }),
        });

        await expect(generateDialog(mockPayload)).rejects.toThrow('Failed to generate dialog: Invalid dialog data');
        expect(fetch).toHaveBeenCalledTimes(1);
    });
});