package adapter

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

	"gitea.dwysokinski.me/twhelp/corev3/internal/bun/bunmodel"
	"gitea.dwysokinski.me/twhelp/corev3/internal/domain"
	"github.com/uptrace/bun"
)

type VersionBunRepository struct {
	db bun.IDB
}

func NewVersionBunRepository(db bun.IDB) *VersionBunRepository {
	return &VersionBunRepository{db: db}
}

func (repo *VersionBunRepository) List(
	ctx context.Context,
	params domain.ListVersionsParams,
) (domain.ListVersionsResult, error) {
	var versions bunmodel.Versions

	if err := repo.db.NewSelect().
		Model(&versions).
		Apply(listVersionsParamsApplier{params: params}.apply).
		Scan(ctx); err != nil && !errors.Is(err, sql.ErrNoRows) {
		return domain.ListVersionsResult{}, fmt.Errorf("couldn't select versions from the database: %w", err)
	}

	converted, err := versions.ToDomain()
	if err != nil {
		return domain.ListVersionsResult{}, err
	}

	return domain.NewListVersionsResult(separateListResultAndNext(converted, params.Limit()))
}

type listVersionsParamsApplier struct {
	params domain.ListVersionsParams
}

func (a listVersionsParamsApplier) apply(q *bun.SelectQuery) *bun.SelectQuery {
	if codes := a.params.Codes(); len(codes) > 0 {
		q = q.Where("version.code IN (?)", bun.In(codes))
	}

	for _, s := range a.params.Sort() {
		cursorZero := a.params.Cursor().IsZero()
		cursorCode := a.params.Cursor().Code()

		switch s {
		case domain.VersionSortCodeASC:
			if !cursorZero {
				q = q.Where("version.code >= ?", cursorCode)
			}

			q = q.Order("version.code ASC")
		case domain.VersionSortCodeDESC:
			if !cursorZero {
				q = q.Where("version.code <= ?", cursorCode)
			}

			q = q.Order("version.code DESC")
		default:
			return q.Err(errUnsupportedSortValue)
		}
	}

	return q.Limit(a.params.Limit() + 1)
}