using HelpDesk.Models.Entities;
using HelpDesk.Models.Enums;
using Microsoft.EntityFrameworkCore;

namespace HelpDesk.Data.Repositories;

public class TicketRepository : ITicketRepository
{
    private readonly HelpDeskDbContext _context;

    public TicketRepository(HelpDeskDbContext context)
    {
        _context = context;
    }

    private IQueryable<Ticket> GetQueryable()
        => _context.Tickets
            .Include(t => t.Requester)
            .Include(t => t.Assignee)
            .Include(t => t.Group)
            .Include(t => t.SlaPolicy)
            .Include(t => t.Comments);

    public async Task<Ticket?> GetByIdAsync(Guid id)
        => await GetQueryable().FirstOrDefaultAsync(t => t.Id == id);

    public async Task<IEnumerable<Ticket>> GetAllAsync(TicketStatus? status, TicketPriority? priority, Guid? assigneeId, Guid? requesterId, int page = 1, int pageSize = 20)
    {
        var query = GetQueryable().AsQueryable();

        if (status.HasValue) query = query.Where(t => t.Status == status.Value);
        if (priority.HasValue) query = query.Where(t => t.Priority == priority.Value);
        if (assigneeId.HasValue) query = query.Where(t => t.AssigneeId == assigneeId.Value);
        if (requesterId.HasValue) query = query.Where(t => t.RequesterId == requesterId.Value);

        return await query.OrderByDescending(t => t.CreatedAt)
            .Skip((page - 1) * pageSize)
            .Take(pageSize)
            .ToListAsync();
    }

    public async Task<int> GetCountAsync(TicketStatus? status, TicketPriority? priority, Guid? assigneeId, Guid? requesterId)
    {
        var query = _context.Tickets.AsQueryable();

        if (status.HasValue) query = query.Where(t => t.Status == status.Value);
        if (priority.HasValue) query = query.Where(t => t.Priority == priority.Value);
        if (assigneeId.HasValue) query = query.Where(t => t.AssigneeId == assigneeId.Value);
        if (requesterId.HasValue) query = query.Where(t => t.RequesterId == requesterId.Value);

        return await query.CountAsync();
    }

    public async Task<Ticket> CreateAsync(Ticket ticket)
    {
        _context.Tickets.Add(ticket);
        await _context.SaveChangesAsync();
        return ticket;
    }

    public async Task<Ticket?> UpdateAsync(Ticket ticket)
    {
        var existing = await _context.Tickets.FindAsync(ticket.Id);
        if (existing == null) return null;

        existing.Title = ticket.Title;
        existing.Description = ticket.Description;
        existing.Priority = ticket.Priority;
        existing.Status = ticket.Status;
        existing.AssigneeId = ticket.AssigneeId;
        existing.GroupId = ticket.GroupId;
        existing.SlaPolicyId = ticket.SlaPolicyId;
        existing.UpdatedAt = DateTime.UtcNow;

        if (ticket.Status == TicketStatus.Resolved && existing.ResolvedAt == null)
            existing.ResolvedAt = DateTime.UtcNow;
        if (ticket.Status == TicketStatus.Closed && existing.ClosedAt == null)
            existing.ClosedAt = DateTime.UtcNow;

        await _context.SaveChangesAsync();
        return existing;
    }

    public async Task<bool> DeleteAsync(Guid id)
    {
        var ticket = await _context.Tickets.FindAsync(id);
        if (ticket == null) return false;
        _context.Tickets.Remove(ticket);
        await _context.SaveChangesAsync();
        return true;
    }

    public async Task<int> GetTotalCountAsync()
        => await _context.Tickets.CountAsync();

    public async Task<int> GetCountByStatusAsync(TicketStatus status)
        => await _context.Tickets.CountAsync(t => t.Status == status);

    public async Task<int> GetCountByPriorityAsync(TicketPriority priority)
        => await _context.Tickets.CountAsync(t => t.Priority == priority);

    public async Task<double> GetAverageResponseTimeAsync()
    {
        var tickets = await _context.Tickets
            .Where(t => t.Comments.Any())
            .Select(t => new
            {
                t.CreatedAt,
                FirstCommentAt = t.Comments.OrderBy(c => c.CreatedAt).Select(c => c.CreatedAt).FirstOrDefault()
            })
            .Where(t => t.FirstCommentAt != default(DateTime))
            .ToListAsync();

        if (!tickets.Any()) return 0;
        return tickets.Average(t => (t.FirstCommentAt - t.CreatedAt).TotalMinutes);
    }

    public async Task<double> GetAverageResolutionTimeAsync()
    {
        var tickets = await _context.Tickets
            .Where(t => t.ResolvedAt.HasValue)
            .Select(t => new { t.CreatedAt, t.ResolvedAt })
            .ToListAsync();

        if (!tickets.Any()) return 0;
        return tickets.Average(t => (t.ResolvedAt!.Value - t.CreatedAt).TotalMinutes);
    }
}