const API_BASE = '/api';

async function request(url: string, options?: RequestInit) {
    const res = await fetch(`${API_BASE}${url}`, {
        headers: { 'Content-Type': 'application/json' },
        ...options,
    });
    if (!res.ok) {
        const err = await res.json().catch(() => ({ error: res.statusText }));
        throw new Error(err.error || 'Request failed');
    }
    return res.json();
}

// Auth
export async function apiLogin(email: string, password: string) {
    return request('/auth/login', {
        method: 'POST',
        body: JSON.stringify({ email, password }),
    });
}

export async function apiRegister(data: {
    name: string; email: string; password: string; role?: string; dept?: string;
}) {
    return request('/auth/register', {
        method: 'POST',
        body: JSON.stringify(data),
    });
}

export async function apiFetchUsers() {
    return request('/auth/users');
}

export async function apiCreateUser(data: {
    name: string; email: string; password: string; role?: string; dept?: string;
}) {
    return request('/auth/users', {
        method: 'POST',
        body: JSON.stringify(data),
    });
}

export async function apiDeleteUser(id: string) {
    return request(`/auth/users/${id}`, {
        method: 'DELETE',
    });
}

export async function apiExportCsv(type: 'tasks' | 'users' | 'activities', month?: string) {
    const params = month ? `?month=${month}` : '';
    const res = await fetch(`${API_BASE}/export/${type}${params}`);
    if (!res.ok) throw new Error('Export failed');
    const blob = await res.blob();
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = month ? `${type}_${month}.csv` : `${type}_all.csv`;
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
    URL.revokeObjectURL(url);
}

// Tasks
export async function apiFetchTasks() {
    return request('/tasks');
}

export async function apiCreateTask(task: {
    title: string; description?: string; status?: string; priority?: string;
    assignee?: string; reporter?: string; dueDate?: string; tags?: string[];
    subtasks?: { title: string; done: boolean }[];
    dependencies?: { dependsOnUserId: string; description: string }[];
}) {
    return request('/tasks', {
        method: 'POST',
        body: JSON.stringify(task),
    });
}

export async function apiUpdateTask(id: string, updates: Record<string, unknown>) {
    return request(`/tasks/${id}`, {
        method: 'PUT',
        body: JSON.stringify(updates),
    });
}

export async function apiAddSubtask(taskId: string, title: string) {
    return request(`/tasks/${taskId}/subtasks`, {
        method: 'POST',
        body: JSON.stringify({ title }),
    });
}

export async function apiToggleSubtask(taskId: string, subtaskId: string, done: boolean) {
    return request(`/tasks/${taskId}/subtasks/${subtaskId}`, {
        method: 'PUT',
        body: JSON.stringify({ done }),
    });
}

export async function apiAddComment(taskId: string, userId: string, text: string) {
    return request(`/tasks/${taskId}/comments`, {
        method: 'POST',
        body: JSON.stringify({ userId, text }),
    });
}

export async function apiAddActivity(taskId: string, text: string) {
    return request(`/tasks/${taskId}/activity`, {
        method: 'POST',
        body: JSON.stringify({ text }),
    });
}

// Dependencies
export async function apiAddDependency(taskId: string, dep: { dependsOnUserId: string; description: string }) {
    return request(`/tasks/${taskId}/dependencies`, {
        method: 'POST',
        body: JSON.stringify(dep),
    });
}

export async function apiToggleDependency(taskId: string, depId: string, resolved: boolean) {
    return request(`/tasks/${taskId}/dependencies/${depId}`, {
        method: 'PUT',
        body: JSON.stringify({ resolved }),
    });
}

export async function apiRemoveDependency(taskId: string, depId: string) {
    return request(`/tasks/${taskId}/dependencies/${depId}`, {
        method: 'DELETE',
    });
}