using System.Text.Json;
using HrynCo.NotificationService.DAL.Abstract.Repositories;
using HrynCo.NotificationService.DAL.Abstract.Templates;
using HrynCo.NotificationService.Web.Controllers.Admin.ViewModels;
using Microsoft.AspNetCore.Mvc;

namespace HrynCo.NotificationService.Web.Controllers.Admin;

[Route("admin/services/{serviceId:guid}/push-templates")]
public sealed class AdminPushTemplatesController(IPushTemplateDefinitionRepository pushes,
    IEmailTemplateDefinitionRepository emails, INotificationServiceRepository services,
    ILogger<AdminPushTemplatesController> logger) : Controller
{
    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web) { WriteIndented = true };

    [HttpGet("email")]
    public async Task<IActionResult> Email([FromRoute] Guid serviceId, string? key, string? keyFilter, CancellationToken ct)
    {
        var service = await services.GetAsync(serviceId, ct);
        if (service is null) return NotFound();
        if (string.IsNullOrEmpty(key))
            return RedirectToAction("Create", "AdminTemplates", new { serviceId, keyFilter });
        var email = await emails.GetDefinitionAsync(serviceId, key, ct);
        if (email is not null)
            return RedirectToAction("Edit", "AdminTemplates", new { serviceId, definitionId = email.Id, keyFilter });
        return Missing(service, key, keyFilter, false);
    }

    [HttpGet("edit")]
    public async Task<IActionResult> Edit([FromRoute] Guid serviceId, string? key, string? keyFilter, CancellationToken ct)
    {
        var service = await services.GetAsync(serviceId, ct);
        if (service is null) return NotFound();
        if (string.IsNullOrEmpty(key))
            return RedirectToAction(nameof(Create), new { serviceId, keyFilter });
        var definition = await pushes.GetAsync(serviceId, key, ct);
        return definition is null ? Missing(service, key, keyFilter, true)
            : Editor(ToModel(definition, service, keyFilter), service);
    }

    [HttpGet("create")]
    public async Task<IActionResult> Create([FromRoute] Guid serviceId, string? key, string? keyFilter, CancellationToken ct)
    {
        var service = await services.GetAsync(serviceId, ct);
        if (service is null) return NotFound();
        if (key is not null && await pushes.GetAsync(serviceId, key, ct) is not null)
            return RedirectToAction(nameof(Edit), new { serviceId, key, keyFilter });
        return Editor(new PushTemplateEditViewModel
        {
            ServiceId = serviceId, ServiceName = service.Name, Key = key ?? "", KeyFilter = keyFilter,
            LockKey = key is not null && await emails.GetDefinitionAsync(serviceId, key, ct) is not null
        }, service);
    }

    [HttpPost("save"), ValidateAntiForgeryToken]
    public async Task<IActionResult> Save([FromRoute] Guid serviceId, PushTemplateEditViewModel model, CancellationToken ct)
    {
        var service = await services.GetAsync(serviceId, ct);
        if (service is null || serviceId != model.ServiceId) return NotFound();
        model.ServiceName = service.Name;
        var persisted = await pushes.GetAsync(serviceId, model.Key, ct);
        if (model.Id is not null && persisted?.Id != model.Id) return NotFound();
        model.LockKey = model.Id is not null || await emails.GetDefinitionAsync(serviceId, model.Key, ct) is not null;
        SetSavedStatuses(model, persisted);
        ValidateCatalog(model, service);
        if (!ModelState.IsValid) return Editor(model, service);
        return await SaveModelAsync(model, service, ct);
    }

    private async Task<IActionResult> SaveModelAsync(PushTemplateEditViewModel model, NotificationServiceInfo service, CancellationToken ct)
    {
        try
        {
            await pushes.SaveAsync(new PushTemplateDefinition
            {
                Id = model.Id ?? Guid.Empty, ServiceId = service.Id, Key = model.Key, Revision = model.Revision,
                Variables = EmailTemplateValidation.ParseVariables(model.VariablesJson),
                Languages = model.Languages.Where(l => l.HasContent).Select(l => new PushTemplateTranslation
                {
                    LanguageCode = l.LanguageCode, Title = l.Title, Body = l.Body, ActionsJson = l.ActionsJson
                }).ToList()
            }, model.IsNew, ct);
            return RedirectToAction("Index", "AdminTemplates", new { serviceId = service.Id, key = model.KeyFilter });
        }
        catch (JsonException) { ModelState.AddModelError("VariablesJson", "Invalid variables JSON. Use name and required properties."); }
        catch (EmailTemplateWriteException error) { ModelState.AddModelError("", error.Message); }
        catch (Exception error) when (error is not OperationCanceledException)
        {
            logger.LogError(error, "Failed to save push template definition");
            ModelState.AddModelError("", "Could not save the push template. Your entered values are retained; try again.");
        }
        return Editor(model, service);
    }

    [HttpGet("delete")]
    public async Task<IActionResult> ConfirmDelete([FromRoute] Guid serviceId, string key, string? keyFilter, CancellationToken ct)
    {
        var service = await services.GetAsync(serviceId, ct);
        var definition = await pushes.GetAsync(serviceId, key, ct);
        return service is null || definition is null ? NotFound() : View("Delete", ToModel(definition, service, keyFilter));
    }

    [HttpPost("delete"), ValidateAntiForgeryToken]
    public async Task<IActionResult> Delete([FromRoute] Guid serviceId, PushTemplateEditViewModel model, CancellationToken ct)
    {
        var service = await services.GetAsync(serviceId, ct);
        var definition = await pushes.GetAsync(serviceId, model.Key, ct);
        if (service is null || definition is null) return NotFound();
        if (!model.ConfirmDelete || !ModelState.IsValid)
            ModelState.AddModelError("", "Confirm deletion of this push template to continue.");
        else
        {
            try
            {
                await pushes.DeleteAsync(serviceId, model.Key, model.Revision, ct);
                return RedirectToAction("Index", "AdminTemplates", new { serviceId, key = model.KeyFilter });
            }
            catch (EmailTemplateWriteException error) { ModelState.AddModelError("", error.Message); }
        }
        var errors = ModelState.Values.SelectMany(v => v.Errors).Select(e => e.ErrorMessage).ToList();
        ModelState.Clear();
        foreach (var error in errors) ModelState.AddModelError("", error);
        return View("Delete", ToModel(definition, service, model.KeyFilter));
    }

    private IActionResult Missing(NotificationServiceInfo service, string key, string? keyFilter, bool isPush) => View("Missing", new TemplateChannelNavigationViewModel
    {
        ServiceId = service.Id, ServiceName = service.Name, Key = key, KeyFilter = keyFilter, IsPush = isPush
    });

    private IActionResult Editor(PushTemplateEditViewModel model, NotificationServiceInfo service)
    {
        foreach (var language in service.Languages)
            if (!model.Languages.Any(l => l.LanguageCode == language.Code))
                model.Languages.Add(new PushTemplateLanguageEditViewModel { LanguageCode = language.Code });
        return View("Edit", model);
    }

    private void ValidateCatalog(PushTemplateEditViewModel model, NotificationServiceInfo service)
    {
        var codes = model.Languages.Select(l => l.LanguageCode).ToHashSet(StringComparer.Ordinal);
        if (codes.Count != model.Languages.Count || !codes.SetEquals(service.Languages.Select(l => l.Code)))
            ModelState.AddModelError("", "The service language catalog changed or the submitted tabs are invalid. Reload before saving.");
    }

    private static void SetSavedStatuses(PushTemplateEditViewModel model, PushTemplateDefinition? persisted)
    {
        var codes = persisted?.Languages.Select(l => l.LanguageCode).ToHashSet(StringComparer.Ordinal) ?? [];
        foreach (var language in model.Languages) language.IsPresent = codes.Contains(language.LanguageCode);
    }

    private static PushTemplateEditViewModel ToModel(PushTemplateDefinition definition, NotificationServiceInfo service, string? keyFilter) => new()
    {
        Id = definition.Id, ServiceId = service.Id, ServiceName = service.Name, Key = definition.Key,
        Revision = definition.Revision, KeyFilter = keyFilter, LockKey = true,
        VariablesJson = JsonSerializer.Serialize(definition.Variables, JsonOptions),
        Languages = definition.Languages.Select(l => new PushTemplateLanguageEditViewModel
        {
            LanguageCode = l.LanguageCode, Title = l.Title, Body = l.Body, ActionsJson = l.ActionsJson, IsPresent = true
        }).ToList()
    };
}