using line_gestao_api.Models;
using line_gestao_api.Services;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;

namespace line_gestao_api.Data;

public class SeedOptions
{
    public bool Enabled { get; set; } = true;
    public string AdminMasterName { get; set; } = "System Admin";
    public string? AdminMasterEmail { get; set; } = "sysadmin@linegestao.local";
    public string? AdminMasterPassword { get; set; } = "DevSysAdmin123!";
    public bool ReapplyAdminCredentialsOnStartup { get; set; } = false;
}

public static class SeedData
{
    public static async Task EnsureSeedDataAsync(IServiceProvider services)
    {
        using var scope = services.CreateScope();
        var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
        var userManager = scope.ServiceProvider.GetRequiredService<UserManager<ApplicationUser>>();
        var roleManager = scope.ServiceProvider.GetRequiredService<RoleManager<IdentityRole<Guid>>>();
        var tenantProvider = scope.ServiceProvider.GetRequiredService<ITenantProvider>();
        var options = scope.ServiceProvider.GetRequiredService<IOptions<SeedOptions>>().Value;

        if (db.Database.IsRelational())
        {
            await db.Database.MigrateAsync();
        }
        else
        {
            await db.Database.EnsureCreatedAsync();
        }

        // Mantem o contrato de roles atualizado em todos os ambientes, inclusive
        // quando o seed de usuario master estiver desabilitado.
        var roles = AppRoles.All;
        foreach (var role in roles)
        {
            if (!await roleManager.RoleExistsAsync(role))
            {
                var roleResult = await roleManager.CreateAsync(new IdentityRole<Guid>(role));
                EnsureIdentitySucceeded(roleResult, $"Falha ao criar role '{role}'.");
            }
        }

        await MigrateLegacyRolesAsync(db, roleManager);

        if (!options.Enabled)
        {
            return;
        }

        var systemTenantId = SystemTenantConstants.SystemTenantId;
        var systemTenant = await db.Tenants.FirstOrDefaultAsync(t => t.Id == systemTenantId);
        if (systemTenant == null)
        {
            systemTenant = new Tenant
            {
                Id = systemTenantId,
                NomeOficial = SystemTenantConstants.SystemTenantNomeOficial,
                IsSystem = true,
                Ativo = true,
                CreatedAt = DateTime.UtcNow
            };
            db.Tenants.Add(systemTenant);
        }
        else
        {
            systemTenant.NomeOficial = SystemTenantConstants.SystemTenantNomeOficial;
            systemTenant.IsSystem = true;
            systemTenant.Ativo = true;
        }

        await db.SaveChangesAsync();

        var emailFromEnv = Environment.GetEnvironmentVariable("SYSADMIN_EMAIL")
                           ?? Environment.GetEnvironmentVariable("ADMIN_MASTER_EMAIL");
        var passwordFromEnv = Environment.GetEnvironmentVariable("SYSADMIN_PASSWORD")
                              ?? Environment.GetEnvironmentVariable("ADMIN_MASTER_PASSWORD");

        var adminMasterEmail = (emailFromEnv ?? options.AdminMasterEmail ?? string.Empty).Trim().ToLowerInvariant();
        var adminMasterPassword = passwordFromEnv ?? options.AdminMasterPassword ?? string.Empty;

        if (string.IsNullOrWhiteSpace(adminMasterEmail) || string.IsNullOrWhiteSpace(adminMasterPassword))
        {
            throw new InvalidOperationException(
                "Credenciais do sysadmin ausentes. Defina SYSADMIN_EMAIL e SYSADMIN_PASSWORD (ou Seed:AdminMasterEmail/Seed:AdminMasterPassword).");
        }

        var normalizedEmail = userManager.NormalizeEmail(adminMasterEmail);

        var previousTenant = tenantProvider.TenantId;
        tenantProvider.SetTenantId(systemTenantId);

        try
        {
            var existingAdminMaster = await userManager.Users
                .IgnoreQueryFilters()
                .FirstOrDefaultAsync(u => u.TenantId == systemTenantId && u.NormalizedEmail == normalizedEmail);

            if (existingAdminMaster == null)
            {
                var adminMaster = new ApplicationUser
                {
                    Name = options.AdminMasterName,
                    Email = adminMasterEmail,
                    UserName = adminMasterEmail,
                    TenantId = systemTenantId,
                    EmailConfirmed = true,
                    IsActive = true,
                    LockoutEnabled = true
                };

                var createResult = await userManager.CreateAsync(adminMaster, adminMasterPassword);
                EnsureIdentitySucceeded(createResult, "Falha ao criar usuário sysadmin.");

                var addRoleResult = await userManager.AddToRoleAsync(adminMaster, SystemTenantConstants.SystemRole);
                EnsureIdentitySucceeded(addRoleResult, "Falha ao associar role sysadmin ao usuário inicial.");
            }
            else
            {
                existingAdminMaster.Name = options.AdminMasterName;
                existingAdminMaster.Email = adminMasterEmail;
                existingAdminMaster.UserName = adminMasterEmail;
                existingAdminMaster.EmailConfirmed = true;
                existingAdminMaster.IsActive = true;
                existingAdminMaster.LockoutEnabled = true;

                var updateResult = await userManager.UpdateAsync(existingAdminMaster);
                EnsureIdentitySucceeded(updateResult, "Falha ao atualizar usuário sysadmin.");

                if (options.ReapplyAdminCredentialsOnStartup)
                {
                    await userManager.SetLockoutEndDateAsync(existingAdminMaster, null);
                    await userManager.ResetAccessFailedCountAsync(existingAdminMaster);

                    var resetToken = await userManager.GeneratePasswordResetTokenAsync(existingAdminMaster);
                    var resetPasswordResult = await userManager.ResetPasswordAsync(existingAdminMaster, resetToken, adminMasterPassword);
                    if (!resetPasswordResult.Succeeded)
                    {
                        var removePasswordResult = await userManager.RemovePasswordAsync(existingAdminMaster);
                        if (removePasswordResult.Succeeded)
                        {
                            var addPasswordResult = await userManager.AddPasswordAsync(existingAdminMaster, adminMasterPassword);
                            EnsureIdentitySucceeded(addPasswordResult, "Falha ao definir senha do sysadmin.");
                        }
                        else
                        {
                            var addPasswordResult = await userManager.AddPasswordAsync(existingAdminMaster, adminMasterPassword);
                            EnsureIdentitySucceeded(addPasswordResult, "Falha ao definir senha do sysadmin.");
                        }
                    }
                }

                if (!await userManager.IsInRoleAsync(existingAdminMaster, SystemTenantConstants.SystemRole))
                {
                    var addRoleResult = await userManager.AddToRoleAsync(existingAdminMaster, SystemTenantConstants.SystemRole);
                    EnsureIdentitySucceeded(addRoleResult, "Falha ao associar role sysadmin ao usuário inicial.");
                }
            }
        }
        finally
        {
            tenantProvider.SetTenantId(previousTenant);
        }
    }

    private static void EnsureIdentitySucceeded(IdentityResult result, string message)
    {
        if (result.Succeeded)
        {
            return;
        }

        var details = string.Join("; ", result.Errors.Select(e => e.Description));
        throw new InvalidOperationException($"{message} Detalhes: {details}");
    }

    private static async Task MigrateLegacyRolesAsync(AppDbContext db, RoleManager<IdentityRole<Guid>> roleManager)
    {
        await MigrateLegacyRoleAsync(db, roleManager, "admin_master", AppRoles.SysAdmin);
        await MigrateLegacyRoleAsync(db, roleManager, "admin", AppRoles.SysAdmin);
        await MigrateLegacyRoleAsync(db, roleManager, "leitura", AppRoles.Cliente);
        await MigrateLegacyRoleAsync(db, roleManager, "operador", AppRoles.Cliente);
    }

    private static async Task MigrateLegacyRoleAsync(
        AppDbContext db,
        RoleManager<IdentityRole<Guid>> roleManager,
        string legacyRole,
        string newRole)
    {
        var legacyRoleId = await roleManager.Roles
            .Where(r => r.Name == legacyRole)
            .Select(r => (Guid?)r.Id)
            .FirstOrDefaultAsync();
        if (!legacyRoleId.HasValue)
        {
            return;
        }

        var newRoleId = await roleManager.Roles
            .Where(r => r.Name == newRole)
            .Select(r => (Guid?)r.Id)
            .FirstOrDefaultAsync();
        if (!newRoleId.HasValue)
        {
            return;
        }

        var legacyUserIds = await db.UserRoles
            .Where(ur => ur.RoleId == legacyRoleId.Value)
            .Select(ur => ur.UserId)
            .Distinct()
            .ToListAsync();
        if (legacyUserIds.Count == 0)
        {
            return;
        }

        var alreadyInNewRole = await db.UserRoles
            .Where(ur => ur.RoleId == newRoleId.Value && legacyUserIds.Contains(ur.UserId))
            .Select(ur => ur.UserId)
            .ToListAsync();
        var existingSet = alreadyInNewRole.ToHashSet();

        foreach (var userId in legacyUserIds)
        {
            if (!existingSet.Contains(userId))
            {
                db.UserRoles.Add(new IdentityUserRole<Guid>
                {
                    UserId = userId,
                    RoleId = newRoleId.Value
                });
            }
        }

        var legacyAssignments = await db.UserRoles
            .Where(ur => ur.RoleId == legacyRoleId.Value)
            .ToListAsync();
        if (legacyAssignments.Count > 0)
        {
            db.UserRoles.RemoveRange(legacyAssignments);
        }

        await db.SaveChangesAsync();

        var legacyRoleStillUsed = await db.UserRoles.AnyAsync(ur => ur.RoleId == legacyRoleId.Value);
        if (!legacyRoleStillUsed)
        {
            var legacyRoleEntity = await roleManager.Roles.FirstOrDefaultAsync(r => r.Id == legacyRoleId.Value);
            if (legacyRoleEntity != null)
            {
                await roleManager.DeleteAsync(legacyRoleEntity);
            }
        }
    }
}