using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Authorization;
using PlotLine.Services;
using PlotLine.ViewModels;

namespace PlotLine.Controllers;

[Authorize]
public sealed class WriterController(
    IWriterWorkspaceService writerWorkspace,
    IWritingScheduleService writingSchedule) : Controller
{
    public async Task<IActionResult> Index(int? projectId)
    {
        var model = await writerWorkspace.GetDashboardAsync(projectId);
        model.WritingSchedule = await writingSchedule.GetTodayDashboardAsync(projectId);
        return View(model);
    }

    public async Task<IActionResult> Chapter(int id)
    {
        var model = await writerWorkspace.GetChapterWorkflowAsync(id);
        return model is null ? NotFound() : View(model);
    }

    public async Task<IActionResult> SchedulePreview(int? writingPlanId)
    {
        var model = await writingSchedule.GetSchedulePreviewAsync(writingPlanId);
        return View(model);
    }

    public async Task<IActionResult> WritingPlans()
    {
        var model = await writingSchedule.GetWritingPlansForManagementAsync();
        return View(model);
    }

    public async Task<IActionResult> EditWritingPlan(int writingPlanId)
    {
        try
        {
            var model = await writingSchedule.GetWritingPlanSettingsAsync(writingPlanId);
            return View(model);
        }
        catch (InvalidOperationException)
        {
            return NotFound();
        }
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> EditWritingPlan(WritingPlanSettingsEditViewModel model)
    {
        if (!model.WritingDayAvailability.Any(x => x.IsAvailable))
        {
            ModelState.AddModelError(string.Empty, "Select at least one writing day.");
            ModelState.AddModelError(nameof(model.WritingDayAvailability), "Select at least one writing day.");
        }

        if (model.DeadlineDate.Date < model.StartDate.Date)
        {
            ModelState.AddModelError(nameof(model.DeadlineDate), "Deadline date must be on or after the start date.");
        }

        if (!ModelState.IsValid)
        {
            await PopulatePlanSettingsDisplayAsync(model);
            return View(model);
        }

        try
        {
            await writingSchedule.UpdateWritingPlanSettingsAsync(model);
            TempData["WritingPlansMessage"] = "Writing plan updated.";
            return RedirectToAction(nameof(WritingPlans));
        }
        catch (InvalidOperationException ex)
        {
            ModelState.AddModelError(string.Empty, ex.Message);
            await PopulatePlanSettingsDisplayAsync(model);
            return View(model);
        }
    }

    public async Task<IActionResult> PreviewRebalance(int writingPlanId)
    {
        var model = await writingSchedule.GetSchedulePreviewAsync(writingPlanId);
        try
        {
            model.RebalancePreview = await writingSchedule.PreviewRebalanceAsync(writingPlanId);
        }
        catch (InvalidOperationException ex)
        {
            TempData["SchedulePreviewError"] = ex.Message;
            return RedirectToAction(nameof(SchedulePreview), new { writingPlanId });
        }

        return View(nameof(SchedulePreview), model);
    }

    public async Task<IActionResult> ScheduleSetup(int? projectId)
    {
        var model = await writingSchedule.GetScheduleSetupAsync(projectId);
        return View(model);
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> ScheduleSetup(WritingScheduleSetupViewModel model)
    {
        if (!model.WritingDayAvailability.Any(x => x.IsAvailable))
        {
            ModelState.AddModelError(string.Empty, "Select at least one writing day.");
            ModelState.AddModelError(nameof(model.WritingDayAvailability), "Select at least one writing day.");
        }

        if (model.DeadlineDate.Date < model.StartDate.Date)
        {
            ModelState.AddModelError(nameof(model.DeadlineDate), "Deadline date must be on or after the start date.");
        }

        if (!ModelState.IsValid)
        {
            await writingSchedule.PopulateScheduleSetupOptionsAsync(model);
            return View(model);
        }

        try
        {
            var result = await writingSchedule.CreateScheduleFromSetupAsync(model);
            if (string.IsNullOrWhiteSpace(result.ValidationMessage))
            {
                TempData["SchedulePreviewMessage"] = $"Writing plan created. {result.GeneratedItemCount} item{(result.GeneratedItemCount == 1 ? "" : "s")} generated.";
            }
            else
            {
                TempData["SchedulePreviewError"] = result.ValidationMessage;
            }

            return RedirectToAction(nameof(SchedulePreview), new { writingPlanId = result.WritingPlanID });
        }
        catch (InvalidOperationException ex)
        {
            ModelState.AddModelError(string.Empty, ex.Message);
            await writingSchedule.PopulateScheduleSetupOptionsAsync(model);
            return View(model);
        }
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> GenerateSchedule(int writingPlanId)
    {
        try
        {
            var items = await writingSchedule.GenerateSchedule(writingPlanId);
            TempData["SchedulePreviewMessage"] = $"{items.Count} item{(items.Count == 1 ? "" : "s")} generated.";
        }
        catch (InvalidOperationException ex)
        {
            TempData["SchedulePreviewError"] = ex.Message;
        }

        return RedirectToAction(nameof(SchedulePreview), new { writingPlanId });
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> DeleteGeneratedSchedule(int writingPlanId)
    {
        try
        {
            await writingSchedule.DeleteScheduleAsync(writingPlanId);
            TempData["SchedulePreviewMessage"] = "Generated schedule deleted.";
        }
        catch (InvalidOperationException ex)
        {
            TempData["SchedulePreviewError"] = ex.Message;
        }
        catch
        {
            TempData["SchedulePreviewError"] = "Generated schedule could not be deleted.";
        }

        return RedirectToAction(nameof(SchedulePreview), new { writingPlanId });
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> ApplyRebalance(int writingPlanId)
    {
        try
        {
            await writingSchedule.ApplyRebalanceAsync(writingPlanId);
            TempData["SchedulePreviewMessage"] = "Schedule rebalanced successfully.";
        }
        catch (InvalidOperationException ex)
        {
            TempData["SchedulePreviewError"] = ex.Message;
        }

        return RedirectToAction(nameof(SchedulePreview), new { writingPlanId });
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> ActivateWritingPlan(int writingPlanId)
    {
        try
        {
            await writingSchedule.ActivateWritingPlanAsync(writingPlanId);
            TempData["WritingPlansMessage"] = "Writing plan activated.";
        }
        catch (InvalidOperationException ex)
        {
            TempData["WritingPlansError"] = ex.Message;
        }

        return RedirectToAction(nameof(WritingPlans));
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> DeactivateWritingPlan(int writingPlanId)
    {
        try
        {
            await writingSchedule.DeactivateWritingPlanAsync(writingPlanId);
            TempData["WritingPlansMessage"] = "Writing plan deactivated.";
        }
        catch (InvalidOperationException ex)
        {
            TempData["WritingPlansError"] = ex.Message;
        }

        return RedirectToAction(nameof(WritingPlans));
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> DeleteWritingPlan(int writingPlanId)
    {
        try
        {
            await writingSchedule.DeleteWritingPlanAsync(writingPlanId);
            TempData["WritingPlansMessage"] = "Writing plan deleted.";
        }
        catch (InvalidOperationException ex)
        {
            TempData["WritingPlansError"] = ex.Message;
        }

        return RedirectToAction(nameof(WritingPlans));
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> RegenerateWritingPlanSchedule(int writingPlanId)
    {
        try
        {
            var items = await writingSchedule.RegenerateScheduleAsync(writingPlanId);
            TempData["WritingPlansMessage"] = $"{items.Count} item{(items.Count == 1 ? "" : "s")} generated.";
        }
        catch (InvalidOperationException ex)
        {
            TempData["WritingPlansError"] = ex.Message;
        }

        return RedirectToAction(nameof(WritingPlans));
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> MarkScheduleItemComplete(int writingScheduleItemId, int? projectId)
    {
        var updated = await writingSchedule.MarkScheduleItemCompleteAsync(writingScheduleItemId);
        TempData[updated ? "WriterWorkspaceMessage" : "WriterWorkspaceError"] = updated
            ? "Writing task marked complete."
            : "Only planned writing tasks can be marked complete.";
        return RedirectToAction(nameof(Index), new { projectId });
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> SkipScheduleItem(int writingScheduleItemId, int? projectId)
    {
        var updated = await writingSchedule.SkipScheduleItemAsync(writingScheduleItemId);
        TempData[updated ? "WriterWorkspaceMessage" : "WriterWorkspaceError"] = updated
            ? "Writing task skipped."
            : "Only planned writing tasks can be skipped.";
        return RedirectToAction(nameof(Index), new { projectId });
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> SaveChapterGoal(ChapterGoalEditViewModel model)
    {
        await writerWorkspace.SaveChapterGoalAsync(model);
        return RedirectToAction(nameof(Chapter), new { id = model.ChapterID });
    }

    private async Task PopulatePlanSettingsDisplayAsync(WritingPlanSettingsEditViewModel model)
    {
        try
        {
            var existing = await writingSchedule.GetWritingPlanSettingsAsync(model.WritingPlanID);
            model.ProjectName = existing.ProjectName;
            model.BookName = existing.BookName;
            model.GoalType = existing.GoalType;
            model.StartDate = existing.StartDate;
            model.RebalanceModeOptions = existing.RebalanceModeOptions;
        }
        catch (InvalidOperationException)
        {
            // The service will surface the ownership/not-found validation message on submit.
        }
    }
}