using AutoMapper;
using Mws.Application.Auth;
using Mws.Application.Common;
using Mws.Application.Permissions;
using Mws.Domain.Users;

namespace Mws.Application.Accounts;

public class AccountService(IUnitOfWork uow, IPasswordHasher passwordHasher, IPermissionService permissions, IMapper mapper) : IAccountService
{
    private const string Screen = "accounts";

    public async Task<List<AccountDto>> GetAccountsAsync(Guid actorUserId, string? term, CancellationToken ct = default)
    {
        await permissions.EnsureAsync(actorUserId, Screen, PermissionAction.View, ct);

        var users = await uow.Users.SearchWithRoleAsync(term, null, ct);
        return mapper.Map<List<AccountDto>>(users);
    }

    public async Task<AccountDto> CreateAccountAsync(Guid actorUserId, CreateAccountRequest request, CancellationToken ct = default)
    {
        await permissions.EnsureAsync(actorUserId, Screen, PermissionAction.Create, ct);

        var username = request.Username.Trim();
        if (string.IsNullOrWhiteSpace(username) || string.IsNullOrWhiteSpace(request.Password))
        {
            throw new BadRequestException("Username and password are required");
        }

        if (await uow.Users.ExistsByUsernameAsync(username, ct))
        {
            throw new BadRequestException("Username already exists");
        }

        var role = await uow.Roles.GetByIdAsync(request.RoleId, ct)
            ?? throw new BadRequestException("Role not found");

        var now = DateTime.UtcNow;
        var user = new User
        {
            Id = Guid.NewGuid(),
            Username = username,
            PasswordHash = passwordHasher.Hash(request.Password),
            DisplayName = request.DisplayName.Trim(),
            RoleId = role.Id,
            IsActive = true,
            CreatedAt = now,
            UpdatedAt = now,
        };

        uow.Users.Add(user);
        await uow.SaveChangesAsync(ct);
        user.Role = role;
        return mapper.Map<AccountDto>(user);
    }

    public async Task<AccountDto> UpdateAccountAsync(Guid actorUserId, Guid id, UpdateAccountRequest request, CancellationToken ct = default)
    {
        await permissions.EnsureAsync(actorUserId, Screen, PermissionAction.Edit, ct);

        var user = await uow.Users.GetByIdWithRoleAsync(id, ct)
            ?? throw new NotFoundException("Account not found");

        var role = await uow.Roles.GetByIdAsync(request.RoleId, ct)
            ?? throw new BadRequestException("Role not found");

        user.DisplayName = request.DisplayName.Trim();
        user.RoleId = role.Id;
        user.Role = role;
        user.IsActive = request.IsActive;
        user.UpdatedAt = DateTime.UtcNow;

        await uow.SaveChangesAsync(ct);
        return mapper.Map<AccountDto>(user);
    }

    public async Task DeleteAccountAsync(Guid actorUserId, Guid id, CancellationToken ct = default)
    {
        await permissions.EnsureAsync(actorUserId, Screen, PermissionAction.Delete, ct);

        var user = await uow.Users.GetByIdAsync(id, ct)
            ?? throw new NotFoundException("Account not found");

        var soleOwnerProjectIds = await uow.Projects.GetOwnedProjectIdsAsync(id, ct);

        foreach (var projectId in soleOwnerProjectIds)
        {
            var ownerCount = await uow.Projects.CountOwnersAsync(projectId, ct);
            if (ownerCount <= 1)
            {
                throw new BadRequestException("Cannot delete an account that is the sole owner of a project");
            }
        }

        uow.Users.Remove(user);
        await uow.SaveChangesAsync(ct);
    }

    public async Task ResetPasswordAsync(Guid actorUserId, Guid id, ResetPasswordRequest request, CancellationToken ct = default)
    {
        await permissions.EnsureAsync(actorUserId, Screen, PermissionAction.Edit, ct);

        if (string.IsNullOrWhiteSpace(request.NewPassword))
        {
            throw new BadRequestException("New password is required");
        }

        var user = await uow.Users.GetByIdAsync(id, ct)
            ?? throw new NotFoundException("Account not found");

        user.PasswordHash = passwordHasher.Hash(request.NewPassword);
        user.UpdatedAt = DateTime.UtcNow;
        await uow.SaveChangesAsync(ct);
    }
}