package personas

import (
	"context"
	"errors"
	"strings"

	"Yimaru-Backend/internal/domain"
	"Yimaru-Backend/internal/ports"

	"github.com/jackc/pgx/v5"
)

var ErrPersonaNotFound = domain.ErrPersonaNotFound

// ErrNameRequired indicates a missing trim-empty name on create.
var ErrNameRequired = errors.New("name is required")

// ErrNameEmptyUpdate indicates an update attempted to clear the persona name.
var ErrNameEmptyUpdate = errors.New("name cannot be empty")

type Service struct {
	store ports.LmsPersonaStore
}

func NewService(store ports.LmsPersonaStore) *Service {
	return &Service{store: store}
}

func clampPage(limit, offset int32) (int32, int32) {
	if limit <= 0 {
		limit = 20
	}
	if limit > 200 {
		limit = 200
	}
	if offset < 0 {
		offset = 0
	}
	return limit, offset
}

func (s *Service) Create(ctx context.Context, in domain.CreateLmsPersonaInput) (domain.LmsPersona, error) {
	name := strings.TrimSpace(in.Name)
	if name == "" {
		return domain.LmsPersona{}, ErrNameRequired
	}
	in.Name = name
	if in.Gender != nil {
		t := strings.TrimSpace(*in.Gender)
		if t == "" {
			in.Gender = nil
		} else {
			in.Gender = &t
		}
	}
	return s.store.CreateLmsPersona(ctx, in)
}

func (s *Service) GetByID(ctx context.Context, id int64) (domain.LmsPersona, error) {
	p, err := s.store.GetLmsPersonaByID(ctx, id)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.LmsPersona{}, ErrPersonaNotFound
		}
		return domain.LmsPersona{}, err
	}
	return p, nil
}

func (s *Service) Update(ctx context.Context, id int64, in domain.UpdateLmsPersonaInput) (domain.LmsPersona, error) {
	if in.Name != nil {
		t := strings.TrimSpace(*in.Name)
		if t == "" {
			return domain.LmsPersona{}, ErrNameEmptyUpdate
		}
		in.Name = &t
	}
	if in.Gender != nil {
		t := strings.TrimSpace(*in.Gender)
		in.Gender = &t // empty string clears stored gender when client sends gender: ""
	}
	p, err := s.store.UpdateLmsPersona(ctx, id, in)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.LmsPersona{}, ErrPersonaNotFound
		}
		return domain.LmsPersona{}, err
	}
	return p, nil
}

func (s *Service) Delete(ctx context.Context, id int64) error {
	if err := s.store.DeleteLmsPersona(ctx, id); err != nil {
		return err
	}
	return nil
}

func (s *Service) List(ctx context.Context, activeOnly bool, limit, offset int32) ([]domain.LmsPersona, int64, error) {
	limit, offset = clampPage(limit, offset)
	return s.store.ListLmsPersonas(ctx, activeOnly, limit, offset)
}