using FastEndpoints;
using Microsoft.EntityFrameworkCore;
using Socialize.Api.Data;
using Socialize.Api.Infrastructure.Security;
using Socialize.Api.Modules.ContentItems.Data;
using Socialize.Api.Modules.ContentItems.Contracts;
using Socialize.Api.Modules.Approvals.Data;
using Socialize.Api.Modules.Approvals.Services;
using Socialize.Api.Modules.Notifications.Contracts;
using Socialize.Api.Modules.Workspaces.Data;
using System.Text.Json;

namespace Socialize.Api.Modules.Approvals.Handlers;

public record SubmitApprovalDecisionRequest(
    string Decision,
    string? ReviewerName,
    string? ReviewerEmail);

public class SubmitApprovalDecisionRequestValidator
    : Validator<SubmitApprovalDecisionRequest>
{
    public SubmitApprovalDecisionRequestValidator()
    {
        RuleFor(x => x.Decision)
            .NotEmpty()
            .Equal("Approved")
            .WithMessage("Only approved decisions are supported.");
        RuleFor(x => x.ReviewerName).MaximumLength(256);
        RuleFor(x => x.ReviewerEmail).MaximumLength(256).EmailAddress().When(x => !string.IsNullOrWhiteSpace(x.ReviewerEmail));
    }
}

public class SubmitApprovalDecisionHandler(
    AppDbContext dbContext,
    AccessScopeService accessScopeService,
    ApprovalWorkflowRuntimeService approvalWorkflowRuntimeService,
    IContentItemActivityWriter activityWriter,
    INotificationEventWriter notificationEventWriter)
    : Endpoint<SubmitApprovalDecisionRequest, ApprovalRequestDto>
{
    public override void Configure()
    {
        Post("/api/approvals/{id}/decisions");
        AllowAnonymous();
        Options(o => o.WithTags("Approvals"));
    }

    public override async Task HandleAsync(SubmitApprovalDecisionRequest request, CancellationToken ct)
    {
        Guid id = Route<Guid>("id");

        ApprovalRequest? approval = await dbContext.ApprovalRequests.SingleOrDefaultAsync(candidate => candidate.Id == id, ct);
        if (approval is null)
        {
            await SendNotFoundAsync(ct);
            return;
        }

        ContentItem? contentItem = await dbContext.ContentItems.SingleOrDefaultAsync(candidate => candidate.Id == approval.ContentItemId, ct);
        if (contentItem is null)
        {
            await SendNotFoundAsync(ct);
            return;
        }

        if (User?.Identity?.IsAuthenticated == true &&
            !await accessScopeService.CanReviewContentAsync(User, contentItem.WorkspaceId, contentItem.ClientId, contentItem.CampaignId, ct))
        {
            await SendForbiddenAsync(ct);
            return;
        }

        Workspace? workspace = await dbContext.Workspaces.SingleOrDefaultAsync(candidate => candidate.Id == contentItem.WorkspaceId, ct);
        if (workspace is null)
        {
            await SendNotFoundAsync(ct);
            return;
        }

        string normalizedDecision = request.Decision.Trim();
        string decidedByName = User?.Identity?.IsAuthenticated == true
            ? User.GetAlias() ?? User.GetName()
            : string.IsNullOrWhiteSpace(request.ReviewerName) ? approval.ReviewerName : request.ReviewerName.Trim();
        string decidedByEmail = User?.Identity?.IsAuthenticated == true
            ? User.GetEmail()
            : string.IsNullOrWhiteSpace(request.ReviewerEmail) ? approval.ReviewerEmail : request.ReviewerEmail.Trim();

        ApprovalDecision decision = new()
        {
            Id = Guid.NewGuid(),
            ApprovalRequestId = approval.Id,
            Decision = normalizedDecision,
            Comment = null,
            DecidedByUserId = User?.Identity?.IsAuthenticated == true ? User.GetUserId() : null,
            DecidedByName = decidedByName,
            DecidedByEmail = decidedByEmail,
            CreatedAt = DateTimeOffset.UtcNow,
        };

        ApprovalWorkflowDecisionResult workflowDecisionResult = await approvalWorkflowRuntimeService
            .ApplyWorkflowStepDecisionAsync(approval, contentItem, workspace, User!, decision, ct);

        if (!workflowDecisionResult.Succeeded)
        {
            AddError(request => request.Decision, workflowDecisionResult.ErrorMessage ?? "The approval decision could not be recorded.");
            await SendErrorsAsync(workflowDecisionResult.StatusCode, ct);
            return;
        }

        if (!workflowDecisionResult.IsWorkflowStep)
        {
            approval.State = normalizedDecision;
            approval.CompletedAt = DateTimeOffset.UtcNow;

            if (normalizedDecision == "Approved")
            {
                contentItem.Status = ApprovalWorkflowRules.GetFinalApprovalStatus(
                    workspace.SchedulePostsAutomaticallyOnApproval,
                    contentItem.DueDate);
            }

            dbContext.ApprovalDecisions.Add(decision);
            await dbContext.SaveChangesAsync(ct);

            await activityWriter.WriteAsync(
                new ContentItemActivityWriteModel(
                    approval.WorkspaceId,
                    approval.ContentItemId,
                    "approval.decision.recorded",
                    "ApprovalDecision",
                    decision.Id,
                    $"{decidedByName} recorded {normalizedDecision} for {contentItem.Title}.",
                    decision.DecidedByUserId,
                    decidedByEmail,
                    JsonSerializer.Serialize(new
                    {
                        stage = approval.Stage,
                        status = contentItem.Status,
                        decision = normalizedDecision,
                    })),
                ct);

            await notificationEventWriter.WriteAsync(
                new NotificationEventWriteModel(
                    approval.WorkspaceId,
                    approval.ContentItemId,
                    "approval.decision.recorded",
                    "ApprovalDecision",
                    decision.Id,
                    $"{decidedByName} recorded {normalizedDecision} for {contentItem.Title}.",
                    null,
                    decidedByEmail,
                    $$"""{"stage":"{{approval.Stage}}","status":"{{contentItem.Status}}"}"""),
                ct);
        }

        List<ApprovalDecision> decisions = await dbContext.ApprovalDecisions
            .Where(candidate => candidate.ApprovalRequestId == approval.Id)
            .OrderByDescending(candidate => candidate.CreatedAt)
            .ToListAsync(ct);

        List<Guid> decidedByUserIds = decisions
            .Where(candidate => candidate.DecidedByUserId.HasValue)
            .Select(candidate => candidate.DecidedByUserId!.Value)
            .Distinct()
            .ToList();

        Dictionary<Guid, string?> decisionPortraits = await dbContext.Users
            .Where(user => decidedByUserIds.Contains(user.Id))
            .ToDictionaryAsync(user => user.Id, user => user.PortraitUrl, ct);

        List<ApprovalDecisionDto> decisionDtos = decisions
            .Select(candidate => new ApprovalDecisionDto(
                candidate.Id,
                candidate.ApprovalRequestId,
                candidate.Decision,
                candidate.Comment,
                candidate.DecidedByUserId,
                candidate.DecidedByName,
                candidate.DecidedByEmail,
                candidate.DecidedByUserId.HasValue
                    ? decisionPortraits.GetValueOrDefault(candidate.DecidedByUserId.Value)
                    : null,
                candidate.CreatedAt))
            .ToList();

        ApprovalRequestDto dto = new(
            approval.Id,
            approval.WorkspaceId,
            approval.ContentItemId,
            approval.WorkflowInstanceId,
            approval.WorkflowStepSortOrder,
            approval.WorkflowStepTargetType,
            approval.WorkflowStepTargetValue,
            approval.WorkflowStepRequiredApproverCount,
            approval.Stage,
            approval.ReviewerName,
            approval.ReviewerEmail,
            approval.RequestedByUserId,
            approval.DueAt,
            approval.State,
            approval.AccessToken,
            approval.SentAt,
            approval.CompletedAt,
            decisionDtos);

        await SendOkAsync(dto, ct);
    }
}