package livechat

import (
	"context"
	"strings"
	"time"

	kratoserrors "github.com/go-kratos/kratos/v3/errors"
)

const (
	TypeSystem = "system"
	TypeChat   = "chat"
	TypeGift   = "gift"
)

var (
	ErrInvalidMessage = kratoserrors.BadRequest("LIVE_CHAT_INVALID", "invalid chat message")
	ErrRoomNotFound   = kratoserrors.NotFound("LIVE_CHAT_ROOM_NOT_FOUND", "live room not found")
	ErrUserNotFound   = kratoserrors.NotFound("LIVE_CHAT_USER_NOT_FOUND", "chat user not found")
)

type Message struct {
	ID           uint
	RoomID       uint
	Type         string
	UserID       uint
	Username     string
	Nickname     string
	Avatar       string
	Content      string
	GiftID       uint
	GiftName     string
	GiftIcon     string
	Quantity     int
	DiamondTotal int64
	CreatedAt    time.Time
}

type GiftSnapshot struct {
	RoomID       uint
	UserID       uint
	Username     string
	Nickname     string
	GiftID       uint
	GiftName     string
	GiftIcon     string
	Quantity     int
	DiamondTotal int64
}

type Repo interface {
	ListRecent(context.Context, uint, int) ([]*Message, error)
	CreateChat(context.Context, uint, uint, string) (*Message, error)
	CreateGift(context.Context, *GiftSnapshot) (*Message, error)
	Clear(context.Context, uint) error
}

type Usecase struct{ repo Repo }

func NewUsecase(repo Repo) *Usecase { return &Usecase{repo: repo} }

func (uc *Usecase) ListRecent(ctx context.Context, roomID uint, limit int) ([]*Message, error) {
	if roomID == 0 {
		return nil, ErrRoomNotFound
	}
	if limit < 1 || limit > 100 {
		limit = 100
	}
	return uc.repo.ListRecent(ctx, roomID, limit)
}

func (uc *Usecase) Send(ctx context.Context, roomID, userID uint, content string) (*Message, error) {
	content = strings.TrimSpace(content)
	if roomID == 0 || userID == 0 || len([]rune(content)) < 1 || len([]rune(content)) > 50 {
		return nil, ErrInvalidMessage
	}
	return uc.repo.CreateChat(ctx, roomID, userID, content)
}

func (uc *Usecase) RecordGift(ctx context.Context, gift *GiftSnapshot) (*Message, error) {
	if gift == nil || gift.RoomID == 0 || gift.UserID == 0 || gift.GiftID == 0 || gift.Quantity < 1 || gift.DiamondTotal < 1 {
		return nil, ErrInvalidMessage
	}
	return uc.repo.CreateGift(ctx, gift)
}

func (uc *Usecase) Clear(ctx context.Context, roomID uint) error {
	if roomID == 0 {
		return ErrRoomNotFound
	}
	return uc.repo.Clear(ctx, roomID)
}