using Microsoft.AspNetCore.Mvc;
using TaskTracker.Core.DTOs;
using TaskTracker.Core.Entities;
using TaskTracker.Core.Enums;
using TaskTracker.Core.Interfaces;

namespace TaskTracker.Api.Controllers;

[ApiController]
[Route("api/[controller]")]
public class TasksController(ITaskRepository taskRepo, ILogger<TasksController> logger) : ControllerBase
{
    [HttpGet]
    public async Task<IActionResult> GetAll([FromQuery] WorkTaskStatus? status, [FromQuery] int? parentId, [FromQuery] bool includeSubTasks = false)
    {
        var tasks = await taskRepo.GetAllAsync(status, parentId, includeSubTasks);
        return Ok(ApiResponse<List<WorkTask>>.Ok(tasks));
    }

    [HttpGet("active")]
    public async Task<IActionResult> GetActive()
    {
        var task = await taskRepo.GetActiveTaskAsync();
        if (task is null)
            return Ok(ApiResponse<WorkTask?>.Ok(null));
        return Ok(ApiResponse<WorkTask>.Ok(task));
    }

    [HttpGet("{id:int}")]
    public async Task<IActionResult> GetById(int id)
    {
        var task = await taskRepo.GetByIdAsync(id);
        if (task is null)
            return NotFound(ApiResponse.Fail("Task not found"));
        return Ok(ApiResponse<WorkTask>.Ok(task));
    }

    [HttpPost]
    public async Task<IActionResult> Create([FromBody] CreateTaskRequest request)
    {
        if (request.ParentTaskId.HasValue)
        {
            var parent = await taskRepo.GetByIdAsync(request.ParentTaskId.Value);
            if (parent is null)
                return BadRequest(ApiResponse.Fail("Parent task not found"));
        }

        var task = new WorkTask
        {
            Title = request.Title,
            Description = request.Description,
            Category = request.Category,
            ParentTaskId = request.ParentTaskId,
            EstimatedMinutes = request.EstimatedMinutes,
            Status = WorkTaskStatus.Pending
        };

        var created = await taskRepo.CreateAsync(task);
        logger.LogInformation("Created task {TaskId}: {Title}", created.Id, created.Title);
        return CreatedAtAction(nameof(GetById), new { id = created.Id }, ApiResponse<WorkTask>.Ok(created));
    }

    [HttpPut("{id:int}/start")]
    public async Task<IActionResult> Start(int id)
    {
        var task = await taskRepo.GetByIdAsync(id);
        if (task is null)
            return NotFound(ApiResponse.Fail("Task not found"));

        // Pause any currently active task
        var active = await taskRepo.GetActiveTaskAsync();
        if (active is not null && active.Id != id)
        {
            active.Status = WorkTaskStatus.Paused;
            await taskRepo.UpdateAsync(active);
        }

        task.Status = WorkTaskStatus.Active;
        task.StartedAt ??= DateTime.UtcNow;
        await taskRepo.UpdateAsync(task);

        logger.LogInformation("Started task {TaskId}", id);
        return Ok(ApiResponse<WorkTask>.Ok(task));
    }

    [HttpPut("{id:int}/pause")]
    public async Task<IActionResult> Pause(int id, [FromBody] TaskActionRequest? request)
    {
        var task = await taskRepo.GetByIdAsync(id);
        if (task is null)
            return NotFound(ApiResponse.Fail("Task not found"));

        task.Status = WorkTaskStatus.Paused;

        if (!string.IsNullOrWhiteSpace(request?.Note))
        {
            task.Notes.Add(new TaskNote
            {
                Content = request.Note,
                Type = NoteType.PauseNote,
                CreatedAt = DateTime.UtcNow
            });
        }

        await taskRepo.UpdateAsync(task);
        logger.LogInformation("Paused task {TaskId}", id);
        return Ok(ApiResponse<WorkTask>.Ok(task));
    }

    [HttpPut("{id:int}/resume")]
    public async Task<IActionResult> Resume(int id, [FromBody] TaskActionRequest? request)
    {
        var task = await taskRepo.GetByIdAsync(id);
        if (task is null)
            return NotFound(ApiResponse.Fail("Task not found"));

        // Pause any currently active task
        var active = await taskRepo.GetActiveTaskAsync();
        if (active is not null && active.Id != id)
        {
            active.Status = WorkTaskStatus.Paused;
            await taskRepo.UpdateAsync(active);
        }

        task.Status = WorkTaskStatus.Active;

        if (!string.IsNullOrWhiteSpace(request?.Note))
        {
            task.Notes.Add(new TaskNote
            {
                Content = request.Note,
                Type = NoteType.ResumeNote,
                CreatedAt = DateTime.UtcNow
            });
        }

        await taskRepo.UpdateAsync(task);
        logger.LogInformation("Resumed task {TaskId}", id);
        return Ok(ApiResponse<WorkTask>.Ok(task));
    }

    [HttpPut("{id:int}/complete")]
    public async Task<IActionResult> Complete(int id)
    {
        var task = await taskRepo.GetByIdAsync(id);
        if (task is null)
            return NotFound(ApiResponse.Fail("Task not found"));

        // Block completion if any subtasks are not completed/abandoned
        var incompleteSubTasks = task.SubTasks
            .Where(st => st.Status != WorkTaskStatus.Completed && st.Status != WorkTaskStatus.Abandoned)
            .ToList();

        if (incompleteSubTasks.Count > 0)
            return BadRequest(ApiResponse.Fail($"Cannot complete task: {incompleteSubTasks.Count} subtask(s) are still incomplete"));

        task.Status = WorkTaskStatus.Completed;
        task.CompletedAt = DateTime.UtcNow;
        await taskRepo.UpdateAsync(task);

        logger.LogInformation("Completed task {TaskId}", id);
        return Ok(ApiResponse<WorkTask>.Ok(task));
    }

    [HttpPut("{id:int}")]
    public async Task<IActionResult> Update(int id, [FromBody] UpdateTaskRequest request)
    {
        var task = await taskRepo.GetByIdAsync(id);
        if (task is null)
            return NotFound(ApiResponse.Fail("Task not found"));

        if (request.Title is not null) task.Title = request.Title;
        if (request.Description is not null) task.Description = request.Description;
        if (request.Category is not null) task.Category = request.Category;
        if (request.EstimatedMinutes.HasValue) task.EstimatedMinutes = request.EstimatedMinutes;

        await taskRepo.UpdateAsync(task);
        return Ok(ApiResponse<WorkTask>.Ok(task));
    }

    [HttpDelete("{id:int}")]
    public async Task<IActionResult> Delete(int id)
    {
        await taskRepo.DeleteAsync(id);
        logger.LogInformation("Abandoned task {TaskId}", id);
        return Ok(ApiResponse.Ok());
    }
}