package adapter

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

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

type ServerSnapshotBunRepository struct {
	db bun.IDB
}

func NewServerSnapshotBunRepository(db bun.IDB) *ServerSnapshotBunRepository {
	return &ServerSnapshotBunRepository{db: db}
}

func (repo *ServerSnapshotBunRepository) Create(
	ctx context.Context,
	params ...domain.CreateServerSnapshotParams,
) error {
	if len(params) == 0 {
		return nil
	}

	now := time.Now()
	snapshots := make(bunmodel.ServerSnapshots, 0, len(params))

	for _, p := range params {
		snapshots = append(snapshots, bunmodel.ServerSnapshot{
			ServerKey:            p.ServerKey(),
			NumPlayers:           p.NumPlayers(),
			NumActivePlayers:     p.NumActivePlayers(),
			NumInactivePlayers:   p.NumInactivePlayers(),
			NumTribes:            p.NumTribes(),
			NumActiveTribes:      p.NumActiveTribes(),
			NumInactiveTribes:    p.NumInactiveTribes(),
			NumVillages:          p.NumVillages(),
			NumPlayerVillages:    p.NumPlayerVillages(),
			NumBarbarianVillages: p.NumBarbarianVillages(),
			NumBonusVillages:     p.NumBonusVillages(),
			Date:                 p.Date(),
			CreatedAt:            now,
		})
	}

	if _, err := repo.db.NewInsert().
		Model(&snapshots).
		Ignore().
		Returning("").
		Exec(ctx); err != nil {
		return fmt.Errorf("something went wrong while inserting server snapshots into the db: %w", err)
	}

	return nil
}

func (repo *ServerSnapshotBunRepository) List(
	ctx context.Context,
	params domain.ListServerSnapshotsParams,
) (domain.ListServerSnapshotsResult, error) {
	var serverSnapshots bunmodel.ServerSnapshots

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

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

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

func (repo *ServerSnapshotBunRepository) ListWithRelations(
	ctx context.Context,
	params domain.ListServerSnapshotsParams,
) (domain.ListServerSnapshotsWithRelationsResult, error) {
	var serverSnapshots bunmodel.ServerSnapshots

	if err := repo.db.NewSelect().
		Model(&serverSnapshots).
		Apply(listServerSnapshotsParamsApplier{params: params}.apply).
		Relation("Server", func(q *bun.SelectQuery) *bun.SelectQuery {
			return q.Column(bunmodel.ServerMetaColumns...)
		}).
		Scan(ctx); err != nil && !errors.Is(err, sql.ErrNoRows) {
		return domain.ListServerSnapshotsWithRelationsResult{}, fmt.Errorf(
			"couldn't select server snapshots from the db: %w",
			err,
		)
	}

	converted, err := serverSnapshots.ToDomainWithRelations()
	if err != nil {
		return domain.ListServerSnapshotsWithRelationsResult{}, err
	}

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

func (repo *ServerSnapshotBunRepository) Delete(ctx context.Context, serverKey string, dateLTE time.Time) error {
	if _, err := repo.db.NewDelete().
		Model((*bunmodel.ServerSnapshot)(nil)).
		Where("server_key = ?", serverKey).
		Where("date <= ?", dateLTE).
		Returning("NULL").
		Exec(ctx); err != nil {
		return fmt.Errorf("couldn't delete server snapshots: %w", err)
	}

	return nil
}

type listServerSnapshotsParamsApplier struct {
	params domain.ListServerSnapshotsParams
}

func (a listServerSnapshotsParamsApplier) apply(q *bun.SelectQuery) *bun.SelectQuery {
	if serverKeys := a.params.ServerKeys(); len(serverKeys) > 0 {
		q = q.Where("ss.server_key IN (?)", bun.In(serverKeys))
	}

	for _, s := range a.params.Sort() {
		column, dir, err := a.sortToColumnAndDirection(s)
		if err != nil {
			return q.Err(err)
		}

		q.OrderExpr("? ?", column, dir.Bun())
	}

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

func (a listServerSnapshotsParamsApplier) applyCursor(q *bun.SelectQuery) *bun.SelectQuery {
	cursor := a.params.Cursor()

	if cursor.IsZero() {
		return q
	}

	sort := a.params.Sort()
	cursorApplier := cursorPaginationApplier{
		data: make([]cursorPaginationApplierDataElement, 0, len(sort)),
	}

	for _, s := range sort {
		var err error
		var el cursorPaginationApplierDataElement

		el.column, el.direction, err = a.sortToColumnAndDirection(s)
		if err != nil {
			return q.Err(err)
		}

		switch s {
		case domain.ServerSnapshotSortIDASC,
			domain.ServerSnapshotSortIDDESC:
			el.value = cursor.ID()
			el.unique = true
		case domain.ServerSnapshotSortServerKeyASC,
			domain.ServerSnapshotSortServerKeyDESC:
			el.value = cursor.ServerKey()
		case domain.ServerSnapshotSortDateASC,
			domain.ServerSnapshotSortDateDESC:
			el.value = cursor.Date()
		default:
			return q.Err(fmt.Errorf("%s: %w", s.String(), errInvalidSortValue))
		}

		cursorApplier.data = append(cursorApplier.data, el)
	}

	return q.Apply(cursorApplier.apply)
}

func (a listServerSnapshotsParamsApplier) sortToColumnAndDirection(
	s domain.ServerSnapshotSort,
) (bun.Safe, sortDirection, error) {
	switch s {
	case domain.ServerSnapshotSortDateASC:
		return "ss.date", sortDirectionASC, nil
	case domain.ServerSnapshotSortDateDESC:
		return "ss.date", sortDirectionDESC, nil
	case domain.ServerSnapshotSortIDASC:
		return "ss.id", sortDirectionASC, nil
	case domain.ServerSnapshotSortIDDESC:
		return "ss.id", sortDirectionDESC, nil
	case domain.ServerSnapshotSortServerKeyASC:
		return "ss.server_key", sortDirectionASC, nil
	case domain.ServerSnapshotSortServerKeyDESC:
		return "ss.server_key", sortDirectionDESC, nil
	default:
		return "", 0, fmt.Errorf("%s: %w", s.String(), errInvalidSortValue)
	}
}