using FlatRender.IdentitySvc.Domain.Entities;
using FlatRender.IdentitySvc.Domain.Enums;
using FlatRender.IdentitySvc.Infrastructure.Data;
using FlatRender.IdentitySvc.Models;
using Microsoft.EntityFrameworkCore;

namespace FlatRender.IdentitySvc.Application.Services;

/// <summary>Admin CRM analytics, customer notes/tags, and per-user power-actions.</summary>
public class AdminService(IdentityDbContext db)
{
    // ── CRM acquisition / conversion analytics ──────────────────────────────

    public async Task<CrmAnalyticsResponse> GetCrmAnalyticsAsync(Guid tenantId, DateTime start, DateTime end)
    {
        // Query-bound dates arrive Kind=Unspecified; Npgsql requires UTC for timestamptz.
        start = DateTime.SpecifyKind(start.Date, DateTimeKind.Utc);
        end = DateTime.SpecifyKind(end.Date.AddDays(1), DateTimeKind.Utc); // inclusive of the end day
        if ((end - start).TotalDays > 366) end = start.AddDays(366);

        var signups = await db.Users
            .Where(u => u.TenantId == tenantId && u.DeletedAt == null && u.RegisterDate >= start && u.RegisterDate < end)
            .Select(u => new { u.Id, u.RegisterDate })
            .ToListAsync();
        var ids = signups.Select(s => s.Id).ToList();

        var buyerIds = await db.Payments
            .Where(p => p.TenantId == tenantId && p.Status == PaymentStatus.Succeeded && ids.Contains(p.UserId))
            .Select(p => p.UserId).Distinct().ToListAsync();

        var pays = await db.Payments
            .Where(p => p.TenantId == tenantId && p.Status == PaymentStatus.Succeeded && p.CreatedAt >= start && p.CreatedAt < end)
            .Select(p => new { p.UserId, p.AmountMinor, p.CreatedAt })
            .ToListAsync();

        var payingAllTime = await db.Payments
            .Where(p => p.TenantId == tenantId && p.Status == PaymentStatus.Succeeded)
            .Select(p => p.UserId).Distinct().CountAsync();

        var daily = new List<CrmDailyPoint>();
        for (var d = start; d < end; d = d.AddDays(1))
        {
            var de = d.AddDays(1);
            var dayPays = pays.Where(p => p.CreatedAt >= d && p.CreatedAt < de).ToList();
            daily.Add(new CrmDailyPoint(
                d.ToString("yyyy-MM-dd"),
                signups.Count(u => u.RegisterDate >= d && u.RegisterDate < de),
                dayPays.Select(p => p.UserId).Distinct().Count(),
                dayPays.Sum(p => p.AmountMinor)));
        }

        var total = signups.Count;
        var buyers = buyerIds.Count;
        return new CrmAnalyticsResponse(
            total, buyers, total - buyers,
            total > 0 ? Math.Round((double)buyers / total * 100, 1) : 0,
            pays.Sum(p => p.AmountMinor), payingAllTime, daily);
    }

    // ── Plan statistics ──────────────────────────────────────────────────────

    public async Task<List<PlanStatRow>> GetPlanStatisticsAsync(Guid tenantId)
    {
        var now = DateTime.UtcNow;
        return await db.UserPlans
            .Where(p => p.TenantId == tenantId)
            .GroupBy(p => p.PlanName)
            .Select(g => new PlanStatRow(
                g.Key,
                g.Count(),
                g.Count(x => x.ExpiresAt > now && x.CancelledAt == null),
                g.Sum(x => x.PriceMinorPaid)))
            .OrderByDescending(r => r.RevenueMinor)
            .ToListAsync();
    }

    // ── CRM notes / tags ────────────────────────────────────────────────────

    public async Task<UserCrmResponse> GetUserCrmAsync(Guid userId)
    {
        var c = await db.Set<UserCrm>().FindAsync(userId);
        return c == null
            ? new UserCrmResponse([], null, "new")
            : new UserCrmResponse(c.Tags, c.Note, c.Status);
    }

    public async Task<UserCrmResponse> UpsertUserCrmAsync(Guid userId, UpsertUserCrmRequest req)
    {
        var c = await db.Set<UserCrm>().FindAsync(userId);
        var isNew = c == null;
        c ??= new UserCrm { UserId = userId };
        if (req.Tags != null) c.Tags = req.Tags;
        if (req.Note != null) c.Note = req.Note;
        if (req.Status != null) c.Status = req.Status;
        c.UpdatedAt = DateTime.UtcNow;
        if (isNew) db.Add(c);
        await db.SaveChangesAsync();
        return new UserCrmResponse(c.Tags, c.Note, c.Status);
    }

    // ── Per-user power-actions ──────────────────────────────────────────────

    private async Task<User> RequireUser(Guid id) =>
        await db.Users.FindAsync(id) ?? throw new KeyNotFoundException("User not found");

    public async Task SetBalanceAsync(Guid userId, long amountMinor, bool add)
    {
        var u = await RequireUser(userId);
        u.BalanceMinor = add ? u.BalanceMinor + amountMinor : amountMinor;
        u.UpdatedAt = DateTime.UtcNow;
        await db.SaveChangesAsync();
    }

    public async Task ResetPasswordAsync(Guid userId, string newPassword)
    {
        var u = await RequireUser(userId);
        u.PasswordHash = BCrypt.Net.BCrypt.HashPassword(newPassword);
        u.PasswordSetAt = DateTime.UtcNow;
        u.UpdatedAt = DateTime.UtcNow;
        await db.SaveChangesAsync();
    }

    public async Task AddChargeAsync(Guid userId, int seconds, int renderCount)
    {
        var u = await RequireUser(userId);
        if (seconds != 0) u.UserDailyFreeChargeSec += seconds;
        if (renderCount != 0)
        {
            u.MaxDailyRenderCount += renderCount;
            u.DailyRemainRenderCount += renderCount;
        }
        u.UpdatedAt = DateTime.UtcNow;
        await db.SaveChangesAsync();
    }

    public async Task SetModeratorAsync(Guid userId, bool enabled)
    {
        var u = await RequireUser(userId);
        u.IsTenantAdmin = enabled;
        u.UpdatedAt = DateTime.UtcNow;
        await db.SaveChangesAsync();
    }

    public async Task GrantPlanDaysAsync(Guid userId, Guid planId, int days)
    {
        var plan = await db.UserPlans
            .Where(p => p.UserId == userId && (planId == Guid.Empty || p.PlanId == planId))
            .OrderByDescending(p => p.ExpiresAt).FirstOrDefaultAsync()
            ?? throw new KeyNotFoundException("No plan found for this user to extend");
        var baseDate = plan.ExpiresAt > DateTime.UtcNow ? plan.ExpiresAt : DateTime.UtcNow;
        plan.ExpiresAt = baseDate.AddDays(days);
        plan.UpdatedAt = DateTime.UtcNow;
        await db.SaveChangesAsync();
    }
}