using Microsoft.EntityFrameworkCore;
using Socialize.Api.Data;

namespace Socialize.Api.Modules.CalendarIntegrations.Services;

public class CalendarExportFeedService(AppDbContext dbContext, CalendarExportFeedBuilder feedBuilder)
{
    public async Task<string> BuildUserFeedAsync(Guid userId, string? userEmail, string appBaseUrl, CancellationToken ct)
    {
        string normalizedEmail = userEmail?.Trim().ToUpperInvariant() ?? string.Empty;
        Guid[] workspaceIds = await dbContext.Workspaces
            .Where(workspace =>
                workspace.OwnerUserId == userId ||
                dbContext.OrganizationMemberships.Any(membership =>
                    membership.OrganizationId == workspace.OrganizationId &&
                    membership.UserId == userId))
            .Select(workspace => workspace.Id)
            .ToArrayAsync(ct);

        List<CalendarExportFeedEvent> events = [];

        events.AddRange(await dbContext.ContentItems
            .Where(item => workspaceIds.Contains(item.WorkspaceId) && item.DueDate.HasValue)
            .Join(
                dbContext.Workspaces,
                item => item.WorkspaceId,
                workspace => workspace.Id,
                (item, workspace) => new { item, workspace })
            .Join(
                dbContext.Clients,
                itemWorkspace => itemWorkspace.item.ClientId,
                client => client.Id,
                (itemWorkspace, client) => new { itemWorkspace.item, itemWorkspace.workspace, client })
            .Join(
                dbContext.Campaigns,
                itemWorkspaceClient => itemWorkspaceClient.item.CampaignId,
                campaign => campaign.Id,
                (itemWorkspaceClient, campaign) => new { itemWorkspaceClient.item, itemWorkspaceClient.workspace, itemWorkspaceClient.client, campaign })
            .Select(candidate => ToContentFeedEvent(
                candidate.item.Id,
                candidate.item.Title,
                candidate.item.Status,
                candidate.item.DueDate!.Value,
                candidate.workspace.Name,
                candidate.client.Name,
                candidate.campaign.Name,
                appBaseUrl))
            .ToListAsync(ct));

        events.AddRange(await dbContext.ApprovalRequests
            .Where(approval =>
                approval.DueAt.HasValue &&
                (approval.RequestedByUserId == userId ||
                 (!string.IsNullOrEmpty(normalizedEmail) && approval.ReviewerEmail.ToUpper() == normalizedEmail)))
            .Join(
                dbContext.ContentItems,
                approval => approval.ContentItemId,
                item => item.Id,
                (approval, item) => new { approval, item })
            .Where(candidate => workspaceIds.Contains(candidate.approval.WorkspaceId))
            .Join(
                dbContext.Workspaces,
                approvalItem => approvalItem.approval.WorkspaceId,
                workspace => workspace.Id,
                (approvalItem, workspace) => new { approvalItem.approval, approvalItem.item, workspace })
            .Select(candidate => ToApprovalFeedEvent(
                candidate.approval.Id,
                candidate.item.Id,
                candidate.item.Title,
                candidate.approval.Stage,
                candidate.approval.State,
                candidate.approval.DueAt!.Value,
                candidate.workspace.Name,
                appBaseUrl))
            .ToListAsync(ct));

        events.AddRange(await dbContext.Campaigns
            .Where(campaign => workspaceIds.Contains(campaign.WorkspaceId))
            .Join(
                dbContext.Workspaces,
                campaign => campaign.WorkspaceId,
                workspace => workspace.Id,
                (campaign, workspace) => new { campaign, workspace })
            .Select(candidate => ToCampaignFeedEvent(
                candidate.campaign.Id,
                candidate.campaign.Name,
                candidate.campaign.Status,
                candidate.campaign.StartDate,
                candidate.campaign.EndDate,
                candidate.workspace.Name,
                appBaseUrl))
            .ToListAsync(ct));

        return feedBuilder.Build("Socialize my work", events);
    }

    private static CalendarExportFeedEvent ToContentFeedEvent(
        Guid contentItemId,
        string title,
        string status,
        DateTimeOffset dueDate,
        string workspaceName,
        string clientName,
        string campaignName,
        string appBaseUrl)
    {
        (DateTimeOffset start, DateTimeOffset end, bool isAllDay) = NormalizeEventTime(dueDate);

        return new CalendarExportFeedEvent(
            $"content-{contentItemId}@socialize",
            title,
            start,
            end,
            isAllDay,
            $"Status: {status}\nWorkspace: {workspaceName}\nClient: {clientName}\nCampaign: {campaignName}",
            $"{appBaseUrl.TrimEnd('/')}/app/content/{contentItemId}");
    }

    private static CalendarExportFeedEvent ToApprovalFeedEvent(
        Guid approvalId,
        Guid contentItemId,
        string contentTitle,
        string stage,
        string state,
        DateTimeOffset dueAt,
        string workspaceName,
        string appBaseUrl)
    {
        (DateTimeOffset start, DateTimeOffset end, bool isAllDay) = NormalizeEventTime(dueAt);

        return new CalendarExportFeedEvent(
            $"approval-{approvalId}@socialize",
            $"Approval due: {contentTitle}",
            start,
            end,
            isAllDay,
            $"Stage: {stage}\nState: {state}\nWorkspace: {workspaceName}",
            $"{appBaseUrl.TrimEnd('/')}/app/content/{contentItemId}");
    }

    private static CalendarExportFeedEvent ToCampaignFeedEvent(
        Guid campaignId,
        string name,
        string status,
        DateTimeOffset startDate,
        DateTimeOffset endDate,
        string workspaceName,
        string appBaseUrl)
    {
        DateTimeOffset start = new(startDate.Date, startDate.Offset);
        DateTimeOffset end = new(endDate.Date.AddDays(1), endDate.Offset);

        return new CalendarExportFeedEvent(
            $"campaign-{campaignId}@socialize",
            $"Campaign: {name}",
            start,
            end <= start ? start.AddDays(1) : end,
            true,
            $"Status: {status}\nWorkspace: {workspaceName}",
            $"{appBaseUrl.TrimEnd('/')}/app/campaigns/{campaignId}");
    }

    private static (DateTimeOffset Start, DateTimeOffset End, bool IsAllDay) NormalizeEventTime(DateTimeOffset value)
    {
        if (value.TimeOfDay == TimeSpan.Zero)
        {
            DateTimeOffset start = new(value.Date, value.Offset);
            return (start, start.AddDays(1), true);
        }

        return (value, value.AddMinutes(30), false);
    }
}