/**
 * Property-Based Tests for API Client
 * Feature: admin-ui-modernization, Property 14: Backend API integration
 * Validates: Requirements 15.1, 15.2, 15.4
 */

import fc from 'fast-check';

// Mock fetch for testing
class MockFetch {
    constructor() {
        this.calls = [];
        this.mockResponse = null;
    }

    reset() {
        this.calls = [];
        this.mockResponse = null;
    }

    setMockResponse(response) {
        this.mockResponse = response;
    }

    async fetch(url, options) {
        this.calls.push({ url, options });
        
        if (this.mockResponse) {
            return this.mockResponse;
        }

        // Default mock response
        return {
            ok: true,
            status: 200,
            headers: {
                get: (key) => {
                    if (key === 'content-type') return 'application/json';
                    return null;
                }
            },
            json: async () => ({ success: true, data: {} })
        };
    }
}

// Simple ApiClient implementation for testing
class ApiClient {
    constructor(baseURL = 'https://test-backend.example.com') {
        this.baseURL = baseURL.replace(/\/$/, '');
        this.cache = new Map();
        this.requestLogs = [];
        this.errorLogs = [];
        this.fetchImpl = null;
    }

    setFetchImpl(fetchImpl) {
        this.fetchImpl = fetchImpl;
    }

    buildUrl(endpoint) {
        if (!endpoint.startsWith('/')) {
            return `${this.baseURL}/${endpoint}`;
        }
        return `${this.baseURL}${endpoint}`;
    }

    async request(method, endpoint, { body, cache = true, ttl = 60000 } = {}) {
        const url = this.buildUrl(endpoint);
        const cacheKey = `${method}:${url}`;

        if (method === 'GET' && cache && this.cache.has(cacheKey)) {
            const cached = this.cache.get(cacheKey);
            if (Date.now() - cached.timestamp < ttl) {
                return { ok: true, data: cached.data, cached: true };
            }
        }

        const started = Date.now();
        const entry = {
            id: `${Date.now()}-${Math.random()}`,
            method,
            endpoint,
            status: 'pending',
            duration: 0,
            time: new Date().toISOString(),
        };

        try {
            const fetchFn = this.fetchImpl || fetch;
            const response = await fetchFn(url, {
                method,
                headers: {
                    'Content-Type': 'application/json',
                },
                body: body ? JSON.stringify(body) : undefined,
            });

            const duration = Date.now() - started;
            entry.duration = Math.round(duration);
            entry.status = response.status;

            const contentType = response.headers.get('content-type') || '';
            let data = null;
            if (contentType.includes('application/json')) {
                data = await response.json();
            } else if (contentType.includes('text')) {
                data = await response.text();
            }

            if (!response.ok) {
                const error = new Error((data && data.message) || response.statusText || 'Unknown error');
                error.status = response.status;
                throw error;
            }

            if (method === 'GET' && cache) {
                this.cache.set(cacheKey, { timestamp: Date.now(), data });
            }

            this.requestLogs.push({ ...entry, success: true });
            return { ok: true, data };
        } catch (error) {
            const duration = Date.now() - started;
            entry.duration = Math.round(duration);
            entry.status = error.status || 'error';
            this.requestLogs.push({ ...entry, success: false, error: error.message });
            this.errorLogs.push({
                message: error.message,
                endpoint,
                method,
                time: new Date().toISOString(),
            });
            return { ok: false, error: error.message };
        }
    }

    get(endpoint, options) {
        return this.request('GET', endpoint, options);
    }

    post(endpoint, body, options = {}) {
        return this.request('POST', endpoint, { ...options, body });
    }
}

// Generators for property-based testing
const httpMethodGen = fc.constantFrom('GET', 'POST');
const endpointGen = fc.oneof(
    fc.constant('/api/health'),
    fc.constant('/api/market'),
    fc.constant('/api/coins'),
    fc.webPath().map(p => `/api/${p}`)
);
const baseURLGen = fc.webUrl({ withFragments: false, withQueryParameters: false });

/**
 * Property 14: Backend API integration
 * For any API request made through apiClient, it should:
 * 1. Use the configured baseURL
 * 2. Return a standardized response format ({ ok, data } or { ok: false, error })
 * 3. Log the request for debugging
 */

console.log('Running Property-Based Tests for API Client...\n');

// Property 1: All requests use the configured baseURL
console.log('Property 1: All requests use the configured baseURL');
fc.assert(
    fc.asyncProperty(
        baseURLGen,
        httpMethodGen,
        endpointGen,
        async (baseURL, method, endpoint) => {
            const client = new ApiClient(baseURL);
            const mockFetch = new MockFetch();
            client.setFetchImpl(mockFetch.fetch.bind(mockFetch));

            await client.request(method, endpoint);

            // Check that the URL starts with the baseURL
            const expectedBase = baseURL.replace(/\/$/, '');
            const actualURL = mockFetch.calls[0].url;
            
            return actualURL.startsWith(expectedBase);
        }
    ),
    { numRuns: 100 }
);
console.log('✓ Property 1 passed: All requests use the configured baseURL\n');

// Property 2: All successful responses have standardized format { ok: true, data }
console.log('Property 2: All successful responses have standardized format');
fc.assert(
    fc.asyncProperty(
        httpMethodGen,
        endpointGen,
        fc.jsonValue(),
        async (method, endpoint, responseData) => {
            const client = new ApiClient('https://test.example.com');
            const mockFetch = new MockFetch();
            
            mockFetch.setMockResponse({
                ok: true,
                status: 200,
                headers: {
                    get: (key) => key === 'content-type' ? 'application/json' : null
                },
                json: async () => responseData
            });
            
            client.setFetchImpl(mockFetch.fetch.bind(mockFetch));

            const result = await client.request(method, endpoint);

            // Check standardized response format
            return (
                typeof result === 'object' &&
                result !== null &&
                'ok' in result &&
                result.ok === true &&
                'data' in result
            );
        }
    ),
    { numRuns: 100 }
);
console.log('✓ Property 2 passed: All successful responses have standardized format\n');

// Property 3: All error responses have standardized format { ok: false, error }
console.log('Property 3: All error responses have standardized format');
fc.assert(
    fc.asyncProperty(
        httpMethodGen,
        endpointGen,
        fc.integer({ min: 400, max: 599 }),
        fc.string({ minLength: 1, maxLength: 100 }),
        async (method, endpoint, statusCode, errorMessage) => {
            const client = new ApiClient('https://test.example.com');
            const mockFetch = new MockFetch();
            
            mockFetch.setMockResponse({
                ok: false,
                status: statusCode,
                statusText: errorMessage,
                headers: {
                    get: (key) => key === 'content-type' ? 'application/json' : null
                },
                json: async () => ({ message: errorMessage })
            });
            
            client.setFetchImpl(mockFetch.fetch.bind(mockFetch));

            const result = await client.request(method, endpoint);

            // Check standardized error response format
            return (
                typeof result === 'object' &&
                result !== null &&
                'ok' in result &&
                result.ok === false &&
                'error' in result &&
                typeof result.error === 'string'
            );
        }
    ),
    { numRuns: 100 }
);
console.log('✓ Property 3 passed: All error responses have standardized format\n');

// Property 4: All requests are logged for debugging
console.log('Property 4: All requests are logged for debugging');
fc.assert(
    fc.asyncProperty(
        httpMethodGen,
        endpointGen,
        async (method, endpoint) => {
            const client = new ApiClient('https://test.example.com');
            const mockFetch = new MockFetch();
            client.setFetchImpl(mockFetch.fetch.bind(mockFetch));

            const initialLogCount = client.requestLogs.length;
            await client.request(method, endpoint);
            const finalLogCount = client.requestLogs.length;

            // Check that a log entry was added
            if (finalLogCount !== initialLogCount + 1) {
                return false;
            }

            // Check that the log entry has required fields
            const logEntry = client.requestLogs[client.requestLogs.length - 1];
            return (
                typeof logEntry === 'object' &&
                logEntry !== null &&
                'method' in logEntry &&
                'endpoint' in logEntry &&
                'status' in logEntry &&
                'duration' in logEntry &&
                'time' in logEntry &&
                'success' in logEntry
            );
        }
    ),
    { numRuns: 100 }
);
console.log('✓ Property 4 passed: All requests are logged for debugging\n');

// Property 5: Error requests are logged in errorLogs
console.log('Property 5: Error requests are logged in errorLogs');
fc.assert(
    fc.asyncProperty(
        httpMethodGen,
        endpointGen,
        fc.integer({ min: 400, max: 599 }),
        async (method, endpoint, statusCode) => {
            const client = new ApiClient('https://test.example.com');
            const mockFetch = new MockFetch();
            
            mockFetch.setMockResponse({
                ok: false,
                status: statusCode,
                statusText: 'Error',
                headers: {
                    get: () => 'application/json'
                },
                json: async () => ({ message: 'Test error' })
            });
            
            client.setFetchImpl(mockFetch.fetch.bind(mockFetch));

            const initialErrorCount = client.errorLogs.length;
            await client.request(method, endpoint);
            const finalErrorCount = client.errorLogs.length;

            // Check that an error log entry was added
            if (finalErrorCount !== initialErrorCount + 1) {
                return false;
            }

            // Check that the error log entry has required fields
            const errorEntry = client.errorLogs[client.errorLogs.length - 1];
            return (
                typeof errorEntry === 'object' &&
                errorEntry !== null &&
                'message' in errorEntry &&
                'endpoint' in errorEntry &&
                'method' in errorEntry &&
                'time' in errorEntry
            );
        }
    ),
    { numRuns: 100 }
);
console.log('✓ Property 5 passed: Error requests are logged in errorLogs\n');

console.log('All property-based tests passed! ✓');