package bundb

import (
	"context"
	"database/sql"
	"errors"
	"fmt"

	"gitea.dwysokinski.me/twhelp/sessions/internal/bundb/internal/model"
	"gitea.dwysokinski.me/twhelp/sessions/internal/domain"
	"github.com/jackc/pgerrcode"
	"github.com/uptrace/bun"
	"github.com/uptrace/bun/driver/pgdriver"
)

type Session struct {
	db *bun.DB
}

func NewSession(db *bun.DB) *Session {
	return &Session{db: db}
}

func (s *Session) CreateOrUpdate(ctx context.Context, params domain.CreateSessionParams) (domain.Session, error) {
	sess := model.NewSession(params)

	if _, err := s.db.NewInsert().
		Model(&sess).
		On("CONFLICT ON CONSTRAINT sessions_user_id_server_key_key DO UPDATE").
		Set("sid = EXCLUDED.sid").
		Set("updated_at = EXCLUDED.updated_at").
		Returning("*").
		Exec(ctx); err != nil {
		return domain.Session{}, fmt.Errorf(
			"something went wrong while inserting session into the db: %w",
			mapCreateSessionError(err, params),
		)
	}

	return sess.ToDomain(), nil
}

func (s *Session) Get(ctx context.Context, userID int64, serverKey string) (domain.Session, error) {
	var sess model.Session

	if err := s.db.NewSelect().
		Model(&sess).
		Where("user_id = ?", userID).
		Where("server_key = ?", serverKey).
		Scan(ctx); err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return domain.Session{}, domain.SessionNotFoundError{ServerKey: serverKey}
		}
		return domain.Session{}, fmt.Errorf(
			"something went wrong while selecting sess (userID=%d,serverKey=%s) from the db: %w",
			userID,
			serverKey,
			err,
		)
	}

	return sess.ToDomain(), nil
}

func mapCreateSessionError(err error, params domain.CreateSessionParams) error {
	var pgError pgdriver.Error
	if !errors.As(err, &pgError) {
		return err
	}

	code := pgError.Field('C')
	constraint := pgError.Field('n')
	switch {
	case code == pgerrcode.ForeignKeyViolation && constraint == "sessions_user_id_fkey":
		return domain.UserDoesNotExistError{
			ID: params.UserID(),
		}
	default:
		return err
	}
}