import { Metrics } from '../entities/Metrics';
import { Task } from '../entities/Task';
import {
    handleAuthResponse,
    getDefaultHeaders,
    getPostHeaders,
} from './authUtils';
import { getApiPath } from '../config/paths';

export interface GroupedTasks {
    [groupName: string]: Task[];
}

export const fetchTasks = async (
    query = ''
): Promise<{
    tasks: Task[];
    metrics: Metrics;
    groupedTasks?: GroupedTasks;
    tasks_in_progress?: Task[];
    tasks_due_today?: Task[];
    suggested_tasks?: Task[];
    tasks_completed_today?: Task[];
    pagination?: {
        total: number;
        limit: number;
        offset: number;
        hasMore: boolean;
    };
}> => {
    // For today view, include dashboard task lists
    const includeLists = query.includes('type=today');
    const tasksQuery =
        includeLists && !query.includes('include_lists')
            ? `${query}${query.includes('?') ? '&' : '?'}include_lists=true`
            : query;

    // Fetch tasks and metrics in parallel for better performance
    const [tasksResponse, metricsResponse] = await Promise.all([
        fetch(getApiPath(`tasks${tasksQuery}`), {
            credentials: 'include',
            headers: getDefaultHeaders(),
        }),
        fetch(getApiPath('tasks/metrics'), {
            credentials: 'include',
            headers: getDefaultHeaders(),
        }),
    ]);

    await handleAuthResponse(tasksResponse, 'Failed to fetch tasks.');
    await handleAuthResponse(metricsResponse, 'Failed to fetch metrics.');

    const tasksResult = await tasksResponse.json();
    const metrics = await metricsResponse.json();

    if (!Array.isArray(tasksResult.tasks)) {
        throw new Error('Resulting tasks are not an array.');
    }

    return {
        tasks: tasksResult.tasks,
        metrics: metrics,
        groupedTasks: tasksResult.groupedTasks,
        // Dashboard task lists (only present when include_lists=true)
        tasks_in_progress: tasksResult.tasks_in_progress,
        tasks_due_today: tasksResult.tasks_due_today,
        suggested_tasks: tasksResult.suggested_tasks,
        tasks_completed_today: tasksResult.tasks_completed_today,
        // Pagination metadata
        pagination: tasksResult.pagination,
    };
};

export const createTask = async (taskData: Task): Promise<Task> => {
    const response = await fetch(getApiPath('task'), {
        method: 'POST',
        credentials: 'include',
        headers: getPostHeaders(),
        body: JSON.stringify(taskData),
    });

    await handleAuthResponse(response, 'Failed to create task.');
    return await response.json();
};

export const updateTask = async (
    taskId: number,
    taskData: Partial<Task>
): Promise<Task> => {
    const response = await fetch(getApiPath(`task/${taskId}`), {
        method: 'PATCH',
        credentials: 'include',
        headers: getPostHeaders(),
        body: JSON.stringify(taskData),
    });

    await handleAuthResponse(response, 'Failed to update task.');
    return await response.json();
};

export const toggleTaskCompletion = async (
    taskId: number,
    currentTask?: Task
): Promise<Task> => {
    const task = currentTask ?? (await fetchTaskById(taskId));

    const newStatus =
        task.status === 2 || task.status === 'done' ? (task.note ? 1 : 0) : 2;

    return await updateTask(taskId, { status: newStatus });
};

export const deleteTask = async (taskId: number): Promise<void> => {
    const response = await fetch(getApiPath(`task/${taskId}`), {
        method: 'DELETE',
        credentials: 'include',
        headers: getDefaultHeaders(),
    });

    await handleAuthResponse(response, 'Failed to delete task.');
};

export const fetchTaskById = async (taskId: number): Promise<Task> => {
    const response = await fetch(getApiPath(`task/${taskId}`), {
        credentials: 'include',
        headers: getDefaultHeaders(),
    });

    await handleAuthResponse(response, 'Failed to fetch task.');
    return await response.json();
};

export const fetchTaskByUid = async (uid: string): Promise<Task> => {
    const response = await fetch(
        getApiPath(`task/${encodeURIComponent(uid)}`),
        {
            credentials: 'include',
            headers: getDefaultHeaders(),
        }
    );

    await handleAuthResponse(response, 'Failed to fetch task.');
    return await response.json();
};

export const fetchSubtasks = async (parentTaskId: number): Promise<Task[]> => {
    const response = await fetch(getApiPath(`task/${parentTaskId}/subtasks`), {
        credentials: 'include',
        headers: getDefaultHeaders(),
    });

    await handleAuthResponse(response, 'Failed to fetch subtasks.');
    return await response.json();
};

export const toggleTaskToday = async (
    taskId: number,
    currentTask?: Task
): Promise<Task> => {
    if (!currentTask) {
        currentTask = await fetchTaskById(taskId);
    }

    return await updateTask(taskId, {
        ...currentTask,
        today: !currentTask.today,
    });
};

export interface TaskIteration {
    date: string;
    utc_date: string;
}

export const fetchTaskNextIterations = async (
    taskId: number,
    startFromDate?: string
): Promise<TaskIteration[]> => {
    const url = startFromDate
        ? getApiPath(
              `task/${taskId}/next-iterations?startFromDate=${startFromDate}`
          )
        : getApiPath(`task/${taskId}/next-iterations`);

    const response = await fetch(url, {
        credentials: 'include',
        headers: getDefaultHeaders(),
    });

    await handleAuthResponse(response, 'Failed to fetch task iterations.');
    const result = await response.json();
    return result.iterations || [];
};