package admin

import (
	"context"
	"encoding/json"
	"strings"

	"github.com/google/uuid"

	"github.com/yuxingu/digital-psychology/apps/api/internal/repository"
)

var (
	ErrPlanNotFound = errString("plan not found")
	ErrInvalidPlanU = errString("invalid plan update")
)

// ListMembershipPlans returns catalog.
func (s *Service) ListMembershipPlans(ctx context.Context) ([]repository.MembershipPlanRow, error) {
	items, err := s.Repo.ListMembershipPlans(ctx)
	if err != nil {
		return nil, err
	}
	if items == nil {
		items = []repository.MembershipPlanRow{}
	}
	return items, nil
}

// GetMembershipPlan returns one plan.
func (s *Service) GetMembershipPlan(ctx context.Context, code string) (*repository.MembershipPlanRow, error) {
	p, err := s.Repo.GetMembershipPlan(ctx, code)
	if err != nil {
		return nil, err
	}
	if p == nil {
		return nil, ErrPlanNotFound
	}
	return p, nil
}

// UpdateMembershipPlan updates mutable fields.
func (s *Service) UpdateMembershipPlan(
	ctx context.Context, adminID uuid.UUID, code, title string, days, amount int, active bool,
) (*repository.MembershipPlanRow, error) {
	code = strings.TrimSpace(code)
	title = strings.TrimSpace(title)
	if title == "" || days <= 0 || amount < 0 {
		return nil, ErrInvalidPlanU
	}
	if _, err := s.GetMembershipPlan(ctx, code); err != nil {
		return nil, err
	}
	meta, _ := json.Marshal(map[string]any{
		"title": title, "duration_days": days, "amount_cents": amount, "active": active,
	})
	if err := s.Repo.UpdateMembershipPlanWithAudit(ctx, adminID, code, title, days, amount, active, meta); err != nil {
		return nil, err
	}
	return s.GetMembershipPlan(ctx, code)
}

// PlanDurationDays resolves grant length from catalog with hardcoded fallback.
func (s *Service) PlanDurationDays(ctx context.Context, plan string) (int, error) {
	p, err := s.Repo.GetMembershipPlan(ctx, plan)
	if err != nil {
		return 0, err
	}
	if p != nil && p.Active && p.DurationDays > 0 {
		return p.DurationDays, nil
	}
	return planDaysFallback(plan)
}

func planDaysFallback(plan string) (int, error) {
	switch plan {
	case "month":
		return 31, nil
	case "quarter":
		return 92, nil
	case "year":
		return 366, nil
	default:
		return 0, ErrInvalidPlan
	}
}