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"
	"github.com/uptrace/bun/dialect"
)

type PlayerBunRepository struct {
	db bun.IDB
}

func NewPlayerBunRepository(db bun.IDB) *PlayerBunRepository {
	return &PlayerBunRepository{db: db}
}

func (repo *PlayerBunRepository) CreateOrUpdate(ctx context.Context, params ...domain.CreatePlayerParams) error {
	if len(params) == 0 {
		return nil
	}

	now := time.Now()
	players := make(bunmodel.Players, 0, len(params))

	for _, p := range params {
		base := p.Base()
		players = append(players, bunmodel.Player{
			ID:                base.ID(),
			ServerKey:         p.ServerKey(),
			Name:              base.Name(),
			NumVillages:       base.NumVillages(),
			Points:            base.Points(),
			Rank:              base.Rank(),
			TribeID:           base.TribeID(),
			ProfileURL:        base.ProfileURL().String(),
			BestRank:          p.BestRank(),
			BestRankAt:        p.BestRankAt(),
			MostPoints:        p.MostPoints(),
			MostPointsAt:      p.MostPointsAt(),
			MostVillages:      p.MostVillages(),
			MostVillagesAt:    p.MostVillagesAt(),
			LastActivityAt:    p.LastActivityAt(),
			CreatedAt:         now,
			OpponentsDefeated: bunmodel.NewOpponentsDefeated(base.OD()),
		})
	}

	q := repo.db.NewInsert().
		Model(&players)

	//nolint:exhaustive
	switch q.Dialect().Name() {
	case dialect.PG:
		q = q.On("CONFLICT ON CONSTRAINT players_pkey DO UPDATE")
	case dialect.SQLite:
		q = q.On("CONFLICT(id, server_key) DO UPDATE")
	default:
		q = q.Err(errors.New("unsupported dialect"))
	}

	if _, err := q.
		Set("name = EXCLUDED.name").
		Set("num_villages = EXCLUDED.num_villages").
		Set("points = EXCLUDED.points").
		Set("rank = EXCLUDED.rank").
		Set("tribe_id = EXCLUDED.tribe_id").
		Set("profile_url = EXCLUDED.profile_url").
		Set("best_rank = EXCLUDED.best_rank").
		Set("best_rank_at = EXCLUDED.best_rank_at").
		Set("most_villages = EXCLUDED.most_villages").
		Set("most_villages_at = EXCLUDED.most_villages_at").
		Set("most_points = EXCLUDED.most_points").
		Set("most_points_at = EXCLUDED.most_points_at").
		Set("last_activity_at = EXCLUDED.last_activity_at").
		Set("deleted_at = EXCLUDED.deleted_at").
		Apply(appendODSetClauses).
		Returning("").
		Exec(ctx); err != nil {
		return fmt.Errorf("something went wrong while inserting players into the db: %w", err)
	}

	return nil
}

func (repo *PlayerBunRepository) List(
	ctx context.Context,
	params domain.ListPlayersParams,
) (domain.ListPlayersResult, error) {
	var players bunmodel.Players

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

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

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

func (repo *PlayerBunRepository) ListWithRelations(
	ctx context.Context,
	params domain.ListPlayersParams,
) (domain.ListPlayersWithRelationsResult, error) {
	var players bunmodel.Players

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

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

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

func (repo *PlayerBunRepository) Delete(ctx context.Context, serverKey string, ids ...int) error {
	if len(ids) == 0 {
		return nil
	}

	if _, err := repo.db.NewUpdate().
		Model((*bunmodel.Player)(nil)).
		Where("deleted_at IS NULL").
		Where("id IN (?)", bun.In(ids)).
		Where("server_key = ?", serverKey).
		Set("deleted_at = ?", time.Now()).
		Set("tribe_id = NULL").
		Returning("").
		Exec(ctx); err != nil {
		return fmt.Errorf("couldn't delete players: %w", err)
	}

	return nil
}

type listPlayersParamsApplier struct {
	params           domain.ListPlayersParams
	includeRelations bool
}

func (a listPlayersParamsApplier) apply(q *bun.SelectQuery) *bun.SelectQuery {
	if ids := a.params.IDs(); len(ids) > 0 {
		q = q.Where("player.id IN (?)", bun.In(ids))
	}

	if serverKeys := a.params.ServerKeys(); len(serverKeys) > 0 {
		q = q.Where("player.server_key IN (?)", bun.In(serverKeys))
	}

	if names := a.params.Names(); len(names) > 0 {
		q = q.Where("player.name IN (?)", bun.In(names))
	}

	if tribeIDs := a.params.TribeIDs(); len(tribeIDs) > 0 {
		q = q.Where("player.tribe_id IN (?)", bun.In(tribeIDs))
	}

	if deleted := a.params.Deleted(); deleted.Valid {
		if deleted.V {
			q = q.Where("player.deleted_at IS NOT NULL")
		} else {
			q = q.Where("player.deleted_at IS NULL")
		}
	}

	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).
		Apply(a.applyRelations)
}

func (a listPlayersParamsApplier) applyRelations(q *bun.SelectQuery) *bun.SelectQuery {
	if a.includeRelations {
		q = q.Relation("Tribe", func(q *bun.SelectQuery) *bun.SelectQuery {
			return q.Column(bunmodel.TribeMetaColumns...)
		})
	}

	if versionCodes := a.params.VersionCodes(); len(versionCodes) > 0 || a.includeRelations {
		q = q.Join("INNER JOIN servers as server").JoinOn("server.key = player.server_key")

		// according to EXPLAIN ANALYZE (https://www.postgresql.org/docs/current/sql-explain.html)
		// this way of filtering servers is much more efficient compared to
		// using the WHERE clause
		if len(versionCodes) > 0 {
			q = q.JoinOn("server.version_code IN (?)", bun.In(versionCodes))
		}

		if a.includeRelations {
			q = q.ColumnExpr("?TableColumns")
			for _, col := range bunmodel.ServerMetaColumns {
				safeCol := bun.Safe(col)
				q = q.ColumnExpr("server.? as server__?", safeCol, safeCol)
			}
		}
	}

	return q
}

//nolint:gocyclo
func (a listPlayersParamsApplier) 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.PlayerSortIDASC,
			domain.PlayerSortIDDESC:
			el.value = cursor.ID()
			el.unique = true
		case domain.PlayerSortServerKeyASC,
			domain.PlayerSortServerKeyDESC:
			el.value = cursor.ServerKey()
		case domain.PlayerSortODScoreAttASC,
			domain.PlayerSortODScoreAttDESC:
			el.value = cursor.ODScoreAtt()
		case domain.PlayerSortODScoreDefASC,
			domain.PlayerSortODScoreDefDESC:
			el.value = cursor.ODScoreDef()
		case domain.PlayerSortODScoreSupASC,
			domain.PlayerSortODScoreSupDESC:
			el.value = cursor.ODScoreSup()
		case domain.PlayerSortODScoreTotalASC,
			domain.PlayerSortODScoreTotalDESC:
			el.value = cursor.ODScoreTotal()
		case domain.PlayerSortPointsASC,
			domain.PlayerSortPointsDESC:
			el.value = cursor.Points()
		case domain.PlayerSortDeletedAtASC,
			domain.PlayerSortDeletedAtDESC:
			el.value = cursor.DeletedAt()
		default:
			return q.Err(fmt.Errorf("%s: %w", s.String(), errInvalidSortValue))
		}

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

	return q.Apply(cursorApplier.apply)
}

//nolint:gocyclo
func (a listPlayersParamsApplier) sortToColumnAndDirection(
	s domain.PlayerSort,
) (bun.Safe, sortDirection, error) {
	switch s {
	case domain.PlayerSortIDASC:
		return "player.id", sortDirectionASC, nil
	case domain.PlayerSortIDDESC:
		return "player.id", sortDirectionDESC, nil
	case domain.PlayerSortServerKeyASC:
		return "player.server_key", sortDirectionASC, nil
	case domain.PlayerSortServerKeyDESC:
		return "player.server_key", sortDirectionDESC, nil
	case domain.PlayerSortODScoreAttASC:
		return "player.score_att", sortDirectionASC, nil
	case domain.PlayerSortODScoreAttDESC:
		return "player.score_att", sortDirectionDESC, nil
	case domain.PlayerSortODScoreDefASC:
		return "player.score_def", sortDirectionASC, nil
	case domain.PlayerSortODScoreDefDESC:
		return "player.score_def", sortDirectionDESC, nil
	case domain.PlayerSortODScoreSupASC:
		return "player.score_sup", sortDirectionASC, nil
	case domain.PlayerSortODScoreSupDESC:
		return "player.score_sup", sortDirectionDESC, nil
	case domain.PlayerSortODScoreTotalASC:
		return "player.score_total", sortDirectionASC, nil
	case domain.PlayerSortODScoreTotalDESC:
		return "player.score_total", sortDirectionDESC, nil
	case domain.PlayerSortPointsASC:
		return "player.points", sortDirectionASC, nil
	case domain.PlayerSortPointsDESC:
		return "player.points", sortDirectionDESC, nil
	case domain.PlayerSortDeletedAtASC:
		return "COALESCE(player.deleted_at, '0001-01-01 00:00:00+00:00')", sortDirectionASC, nil
	case domain.PlayerSortDeletedAtDESC:
		return "COALESCE(player.deleted_at, '0001-01-01 00:00:00+00:00')", sortDirectionDESC, nil
	default:
		return "", 0, fmt.Errorf("%s: %w", s.String(), errInvalidSortValue)
	}
}