package drivers

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
	Nickname  string
	Name      string
	AvatarURL string
	ClanID    string
}

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

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

// GetByNickname loads a driver by nickname.
func (s *Service) GetByNickname(ctx context.Context, nick string) (Driver, error) {
	nick = strings.ToUpper(strings.TrimSpace(nick))
	return s.pg.GetByNickname(ctx, nick)
}

// List returns drivers with limit/offset and optional clan filter.
func (s *Service) List(ctx context.Context, limit, offset int, clanID string) ([]Driver, error) {
	return s.pg.List(ctx, limit, offset, clanID)
}

// UpdateInput is the patch payload.
type UpdateInput struct {
	Name      string
	AvatarURL string
	ClanID    *string // nil = leave unchanged, &"" = clear, &"..." = set
}

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

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