using FastEndpoints;
using Microsoft.EntityFrameworkCore;
using Socialize.Api.Data;
using Socialize.Api.Infrastructure.Security;
using Socialize.Api.Modules.CalendarIntegrations.Data;
using Socialize.Api.Modules.CalendarIntegrations.Services;
using Socialize.Api.Modules.Organizations.Services;

namespace Socialize.Api.Modules.CalendarIntegrations.Handlers;

public class CreateCalendarSourceHandler(
    AppDbContext dbContext,
    AccessScopeService accessScopeService,
    OrganizationAccessService organizationAccessService)
    : Endpoint<UpsertCalendarSourceRequest, CalendarSourceDto>
{
    public override void Configure()
    {
        Post("/api/calendar-integrations/sources");
        Options(o => o.WithTags("Calendar Integrations"));
    }

    public override async Task HandleAsync(UpsertCalendarSourceRequest request, CancellationToken ct)
    {
        ArgumentNullException.ThrowIfNull(request);

        Guid currentUserId = User.GetUserId();
        string scope = request.Scope.Trim();
        Guid? organizationId = request.OrganizationId;
        Guid? workspaceId = request.WorkspaceId;

        if (!await CanCreateAsync(scope, organizationId, workspaceId, currentUserId, ct))
        {
            await SendForbiddenAsync(ct);
            return;
        }

        string? sourceUrl = NormalizeOptional(request.SourceUrl);
        string? catalogSourceReference = NormalizeOptional(request.CatalogSourceReference);
        if (await SourceAlreadyExistsAsync(scope, organizationId, workspaceId, currentUserId, sourceUrl, catalogSourceReference, ct))
        {
            AddError(request => request.SourceUrl, "This calendar source has already been added.");
            await SendErrorsAsync(cancellation: ct);
            return;
        }

        CalendarSource source = new()
        {
            Id = Guid.NewGuid(),
            Scope = scope,
            OrganizationId = scope == CalendarSourceScopes.Organization ? organizationId : null,
            WorkspaceId = scope == CalendarSourceScopes.Workspace ? workspaceId : null,
            UserId = scope == CalendarSourceScopes.User ? currentUserId : null,
            SourceUrl = sourceUrl,
            CatalogSourceReference = catalogSourceReference,
            DisplayTitle = request.DisplayTitle.Trim(),
            Color = request.Color.Trim(),
            Category = request.Category.Trim(),
            IsEnabled = request.IsEnabled,
            InheritanceMode = scope == CalendarSourceScopes.Organization
                ? NormalizeOptional(request.InheritanceMode) ?? CalendarSourceInheritanceModes.Optional
                : null,
            UpdatedAt = DateTimeOffset.UtcNow,
        };

        dbContext.CalendarSources.Add(source);
        await dbContext.SaveChangesAsync(ct);

        await SendAsync(CalendarSourceDto.FromSource(source, isReadOnly: false), StatusCodes.Status201Created, ct);
    }

    private async Task<bool> CanCreateAsync(
        string scope,
        Guid? organizationId,
        Guid? workspaceId,
        Guid currentUserId,
        CancellationToken ct)
    {
        return scope switch
        {
            CalendarSourceScopes.Organization when organizationId.HasValue =>
                await dbContext.Organizations.AnyAsync(organization => organization.Id == organizationId.Value, ct) &&
                await organizationAccessService.HasOrganizationPermissionAsync(
                    User,
                    organizationId.Value,
                    OrganizationPermissions.ManageConnectors,
                    ct),
            CalendarSourceScopes.Workspace when workspaceId.HasValue =>
                await dbContext.Workspaces.AnyAsync(workspace => workspace.Id == workspaceId.Value, ct) &&
                await accessScopeService.CanManageWorkspaceAsync(User, workspaceId.Value, ct),
            CalendarSourceScopes.User => currentUserId != Guid.Empty,
            _ => false,
        };
    }

    private Task<bool> SourceAlreadyExistsAsync(
        string scope,
        Guid? organizationId,
        Guid? workspaceId,
        Guid currentUserId,
        string? sourceUrl,
        string? catalogSourceReference,
        CancellationToken ct)
    {
        IQueryable<CalendarSource> query = dbContext.CalendarSources
            .Where(source => source.Scope == scope);

        query = scope switch
        {
            CalendarSourceScopes.Organization => query.Where(source => source.OrganizationId == organizationId),
            CalendarSourceScopes.Workspace => query.Where(source => source.WorkspaceId == workspaceId),
            CalendarSourceScopes.User => query.Where(source => source.UserId == currentUserId),
            _ => query.Where(_ => false),
        };

        string? normalizedUrl = sourceUrl?.Trim();
        string? normalizedCatalogReference = catalogSourceReference?.Trim();

        return query.AnyAsync(source =>
            (!string.IsNullOrWhiteSpace(normalizedCatalogReference) &&
             source.CatalogSourceReference == normalizedCatalogReference) ||
            (!string.IsNullOrWhiteSpace(normalizedUrl) &&
             source.SourceUrl != null &&
             source.SourceUrl.ToUpper() == normalizedUrl.ToUpper()),
            ct);
    }

    private static string? NormalizeOptional(string? value)
    {
        return string.IsNullOrWhiteSpace(value) ? null : value.Trim();
    }
}