package service

import (
	"context"
	"errors"
	"slices"

	"gitrepo.ru/neonxp/nquest/pkg/models"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

var (
	ErrTeamNotFound = errors.New("team not found")
)

type Team struct {
	DB *gorm.DB
}

// NewTeam returns new Team.
func NewTeam(db *gorm.DB) *Team {
	return &Team{
		DB: db,
	}
}

func (ts *Team) List(ctx context.Context) ([]*models.Team, error) {
	teams := []*models.Team{}

	return teams, ts.DB.WithContext(ctx).Preload("Members").Find(&teams).Error
}

func (ts *Team) Create(ctx context.Context, name string, user *models.User) (*models.Team, error) {
	t := &models.Team{
		Name: name,
		Members: []*models.TeamMember{{
			User: user,
			Role: models.Captain,
		}},
	}

	db := ts.DB.WithContext(ctx)

	if err := db.Delete(&models.TeamRequest{}, `user_id = ?`, user.ID).Error; err != nil {
		return t, err
	}

	return t, db.Create(t).Error
}

func (ts *Team) GetByID(ctx context.Context, id uint) (*models.Team, error) {
	t := new(models.Team)

	err := ts.DB.
		WithContext(ctx).
		Preload("Members").
		Preload("Members.User").
		Preload("Requests").
		Preload("Requests.User").
		First(t, id).
		Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrTeamNotFound
		}

		return nil, err
	}

	return t, nil
}

func (ts *Team) Request(ctx context.Context, team *models.Team, user *models.User) error {
	return ts.DB.
		WithContext(ctx).
		Clauses(clause.OnConflict{DoNothing: true}).
		Create(&models.TeamRequest{
			Team: team,
			User: user,
		}).
		Error
}

func (ts *Team) ApproveMember(ctx context.Context, team *models.Team, user *models.User) error {
	team.Requests = slices.DeleteFunc(team.Requests, func(tr *models.TeamRequest) bool {
		return tr.UserID == user.ID
	})

	team.Members = append(team.Members, &models.TeamMember{
		Team: team,
		User: user,
		Role: models.Member,
	})

	db := ts.DB.WithContext(ctx)
	if err := db.Delete(&models.TeamRequest{}, `user_id = ?`, user.ID).Error; err != nil {
		return err
	}

	return db.Save(team).Error
}

func (ts *Team) DeclineMember(ctx context.Context, team *models.Team, user *models.User) error {
	team.Requests = slices.DeleteFunc(team.Requests, func(tr *models.TeamRequest) bool {
		return tr.UserID == user.ID
	})
	db := ts.DB.WithContext(ctx)
	if err := db.Delete(&models.TeamRequest{}, `user_id = ?`, user.ID).Error; err != nil {
		return err
	}

	return db.Session(&gorm.Session{FullSaveAssociations: true}).Updates(team).Error
}

func (ts *Team) RemoveMember(ctx context.Context, team *models.Team, user *models.User) error {
	return ts.DB.WithContext(ctx).Delete(&models.TeamMember{}, `user_id = ? and team_id = ?`, user.ID, team.ID).Error
}