package clans

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"time"

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

// Service composes validation on top of PgStore.
type Service struct {
	pg *PgStore
	now func() time.Time
}

// NewService wires a service.
func NewService(pg *PgStore) *Service {
	return &Service{pg: pg, now: time.Now}
}

// CreateInput is what the HTTP handler hands to the service.
type CreateInput struct {
	ID        string
	Tag       string
	Name      string
	AvatarURL string
}

// Create validates and inserts a clan.
func (s *Service) Create(ctx context.Context, in CreateInput) (Clan, error) {
	tag := strings.ToUpper(strings.TrimSpace(in.Tag))
	if !IsValidTag(tag) {
		return Clan{}, fmt.Errorf("%w: tag must be 3 uppercase ASCII letters", ErrInvalidInput)
	}
	name := strings.TrimSpace(in.Name)
	if name == "" {
		return Clan{}, fmt.Errorf("%w: name required", ErrInvalidInput)
	}
	c := Clan{
		ID:        in.ID,
		Tag:       tag,
		Name:      name,
		AvatarURL: in.AvatarURL,
	}
	if c.ID == "" {
		c.ID = fmt.Sprintf("clan-%d-%d", s.now().UnixMilli(), time.Now().UnixNano()%1000)
	}
	if err := s.pg.Create(ctx, c); err != nil {
		var pgErr *pgconn.PgError
		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
			return Clan{}, fmt.Errorf("%w: %s", ErrAlreadyExists, tag)
		}
		return Clan{}, err
	}
	return s.pg.Get(ctx, c.ID)
}

// Get loads a clan by id.
func (s *Service) Get(ctx context.Context, id string) (Clan, error) {
	return s.pg.Get(ctx, id)
}

// GetByTag loads a clan by tag.
func (s *Service) GetByTag(ctx context.Context, tag string) (Clan, error) {
	tag = strings.ToUpper(strings.TrimSpace(tag))
	return s.pg.GetByTag(ctx, tag)
}

// List returns clans with limit/offset.
func (s *Service) List(ctx context.Context, limit, offset int) ([]Clan, error) {
	return s.pg.List(ctx, limit, offset)
}

// UpdateInput is the patch payload.
type UpdateInput struct {
	Name      string
	AvatarURL string
}

// Update applies a partial patch.
func (s *Service) Update(ctx context.Context, id string, in UpdateInput) (Clan, error) {
	cur, err := s.pg.Get(ctx, id)
	if err != nil {
		return Clan{}, err
	}
	if in.Name != "" {
		cur.Name = in.Name
	}
	if in.AvatarURL != "" {
		cur.AvatarURL = in.AvatarURL
	}
	if err := s.pg.Update(ctx, cur); err != nil {
		return Clan{}, err
	}
	return s.pg.Get(ctx, id)
}

// Delete removes a clan.
func (s *Service) Delete(ctx context.Context, id string) error {
	return s.pg.Delete(ctx, id)
}