package adapter

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

	"gitea.dwysokinski.me/twhelp/dcbot/internal/adapter/internal/bunmodel"
	"gitea.dwysokinski.me/twhelp/dcbot/internal/domain"
	"github.com/google/uuid"
	"github.com/jackc/pgerrcode"
	"github.com/uptrace/bun"
	"github.com/uptrace/bun/driver/pgdriver"
)

type GroupBunRepository struct {
	db *bun.DB
}

func NewGroupBunRepository(db *bun.DB) *GroupBunRepository {
	return &GroupBunRepository{db: db}
}

func (g *GroupBunRepository) Create(ctx context.Context, params domain.CreateGroupParams) (domain.GroupWithMonitors, error) {
	group := bunmodel.Group{
		ServerID:      params.ServerID(),
		VersionCode:   params.VersionCode(),
		ChannelGains:  params.ChannelGains(),
		ChannelLosses: params.ChannelLosses(),
		ServerKey:     params.ServerKey(),
		Barbarians:    params.Barbarians(),
		Internals:     params.Internals(),
		LanguageTag:   params.LanguageTag(),
	}

	if _, err := g.db.NewInsert().
		Model(&group).
		Returning("*").
		Exec(ctx); err != nil {
		return domain.GroupWithMonitors{}, fmt.Errorf("something went wrong while inserting group into the db: %w", err)
	}

	return group.ToDomain(), nil
}

func (g *GroupBunRepository) Update(ctx context.Context, id string, params domain.UpdateGroupParams) (domain.GroupWithMonitors, error) {
	if params.IsZero() {
		return domain.GroupWithMonitors{}, domain.ErrNothingToUpdate
	}

	if _, err := uuid.Parse(id); err != nil {
		return domain.GroupWithMonitors{}, domain.GroupNotFoundError{ID: id}
	}

	var group bunmodel.Group

	res, err := g.db.NewUpdate().
		Model(&group).
		Returning("NULL").
		Where("id = ?", id).
		Apply(updateGroupsParamsApplier{params}.apply).
		Exec(ctx)
	if err != nil && !errors.Is(err, sql.ErrNoRows) {
		return domain.GroupWithMonitors{}, fmt.Errorf("couldn't update group (id=%s): %w", id, err)
	}
	if affected, _ := res.RowsAffected(); affected == 0 {
		return domain.GroupWithMonitors{}, domain.GroupNotFoundError{ID: id}
	}

	return g.Get(ctx, id)
}

func (g *GroupBunRepository) AddMonitor(ctx context.Context, id string, tribeID int64) (domain.GroupWithMonitors, error) {
	parsedID, err := uuid.Parse(id)
	if err != nil {
		return domain.GroupWithMonitors{}, domain.GroupDoesNotExistError{ID: id}
	}

	monitor := bunmodel.Monitor{
		GroupID: parsedID,
		TribeID: tribeID,
	}

	if _, err = g.db.NewInsert().
		Model(&monitor).
		Returning("NULL").
		Exec(ctx); err != nil {

		return domain.GroupWithMonitors{}, fmt.Errorf(
			"something went wrong while inserting monitor into the db: %w",
			mapAddMonitorError(err, id, tribeID),
		)
	}

	return g.Get(ctx, id)
}

func (g *GroupBunRepository) DeleteMonitors(ctx context.Context, id string, monitorIDs ...string) (domain.GroupWithMonitors, error) {
	if _, err := uuid.Parse(id); err != nil {
		return domain.GroupWithMonitors{}, domain.GroupNotFoundError{ID: id}
	}

	for _, monitorID := range monitorIDs {
		if _, err := uuid.Parse(monitorID); err != nil {
			return domain.GroupWithMonitors{}, domain.MonitorNotFoundError{ID: monitorID}
		}
	}

	_, err := g.db.NewDelete().
		Model(&bunmodel.Monitor{}).
		Returning("NULL").
		Where("id IN (?)", bun.In(monitorIDs)).
		Where("group_id = ?", id).
		Exec(ctx)
	if err != nil && !errors.Is(err, sql.ErrNoRows) {
		return domain.GroupWithMonitors{}, fmt.Errorf("couldn't delete monitors: %w", err)
	}

	return g.Get(ctx, id)
}

func (g *GroupBunRepository) List(ctx context.Context, params domain.ListGroupsParams) ([]domain.GroupWithMonitors, error) {
	var groups []bunmodel.Group

	if err := g.db.NewSelect().
		Model(&groups).
		Order("created_at ASC").
		Relation("Monitors", func(q *bun.SelectQuery) *bun.SelectQuery {
			return q.Order("created_at ASC")
		}).
		Apply(listGroupsParamsApplier{params}.apply).
		Scan(ctx); err != nil && !errors.Is(err, sql.ErrNoRows) {
		return nil, fmt.Errorf("couldn't select groups from the db: %w", err)
	}

	result := make([]domain.GroupWithMonitors, 0, len(groups))
	for _, group := range groups {
		result = append(result, group.ToDomain())
	}

	return result, nil
}

func (g *GroupBunRepository) Get(ctx context.Context, id string) (domain.GroupWithMonitors, error) {
	group, err := g.get(ctx, id, true)
	if err != nil {
		return domain.GroupWithMonitors{}, err
	}
	return group.ToDomain(), nil
}

func (g *GroupBunRepository) get(ctx context.Context, id string, withMonitors bool) (bunmodel.Group, error) {
	if _, err := uuid.Parse(id); err != nil {
		return bunmodel.Group{}, domain.GroupNotFoundError{ID: id}
	}

	var group bunmodel.Group

	q := g.db.NewSelect().
		Model(&group).
		Where("id = ?", id)
	if withMonitors {
		q = q.Relation("Monitors", func(q *bun.SelectQuery) *bun.SelectQuery {
			return q.Order("created_at ASC")
		})
	}

	if err := q.Scan(ctx); err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return bunmodel.Group{}, domain.GroupNotFoundError{ID: id}
		}
		return bunmodel.Group{}, fmt.Errorf("couldn't select group (id=%s) from the db: %w", id, err)
	}

	return group, nil
}

func (g *GroupBunRepository) Delete(ctx context.Context, id string) error {
	if _, err := uuid.Parse(id); err != nil {
		return domain.GroupNotFoundError{ID: id}
	}

	res, err := g.db.NewDelete().
		Model(&bunmodel.Group{}).
		Returning("NULL").
		Where("id = ?", id).
		Exec(ctx)
	if err != nil && !errors.Is(err, sql.ErrNoRows) {
		return fmt.Errorf("couldn't delete group (id=%s): %w", id, err)
	}
	if affected, _ := res.RowsAffected(); affected == 0 {
		return domain.GroupNotFoundError{ID: id}
	}

	return nil
}

func (g *GroupBunRepository) DeleteMany(ctx context.Context, ids ...string) error {
	if len(ids) == 0 {
		return nil
	}

	_, err := g.db.NewDelete().
		Model(&bunmodel.Group{}).
		Returning("NULL").
		Where("id IN (?)", bun.In(ids)).
		Exec(ctx)
	if err != nil && !errors.Is(err, sql.ErrNoRows) {
		return fmt.Errorf("couldn't delete groups: %w", err)
	}
	return nil
}

type updateGroupsParamsApplier struct {
	params domain.UpdateGroupParams
}

func (u updateGroupsParamsApplier) apply(q *bun.UpdateQuery) *bun.UpdateQuery {
	if u.params.ChannelGains.Valid {
		if u.params.ChannelGains.String != "" {
			q = q.Set("channel_gains = ?", u.params.ChannelGains.String)
		} else {
			q = q.Set("channel_gains = NULL")
		}
	}

	if u.params.ChannelLosses.Valid {
		if u.params.ChannelLosses.String != "" {
			q = q.Set("channel_losses = ?", u.params.ChannelLosses.String)
		} else {
			q = q.Set("channel_losses = NULL")
		}
	}

	if u.params.LanguageTag.Valid {
		if u.params.LanguageTag.String != "" {
			q = q.Set("language_tag = ?", u.params.LanguageTag.String)
		} else {
			q = q.Set("language_tag = NULL")
		}
	}

	if u.params.Barbarians.Valid {
		q = q.Set("barbarians = ?", u.params.Barbarians.Bool)
	}

	if u.params.Internals.Valid {
		q = q.Set("internals = ?", u.params.Internals.Bool)
	}

	return q
}

type listGroupsParamsApplier struct {
	params domain.ListGroupsParams
}

func (l listGroupsParamsApplier) apply(q *bun.SelectQuery) *bun.SelectQuery {
	if len(l.params.ServerIDs) > 0 {
		q = q.Where("server_id IN (?)", bun.In(l.params.ServerIDs))
	}

	if l.params.EnabledNotifications.Valid {
		if l.params.EnabledNotifications.Bool {
			q = q.WhereGroup(" AND ", func(query *bun.SelectQuery) *bun.SelectQuery {
				return q.WhereOr("channel_gains IS NOT NULL").
					WhereOr("channel_losses IS NOT NULL")
			})
		} else {
			q = q.Where("channel_gains IS NULL").Where("channel_losses IS NULL")
		}
	}

	if l.params.VersionCode.Valid {
		q = q.Where("version_code = ?", l.params.VersionCode.String)
	}

	if len(l.params.ServerKeys) > 0 {
		q = q.Where("server_key IN (?)", bun.In(l.params.ServerKeys))
	}

	if !l.params.CreatedAtLTE.IsZero() {
		q = q.Where("created_at <= ?", l.params.CreatedAtLTE)
	}

	return q
}

func mapAddMonitorError(err error, groupID string, tribeID int64) 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 == "monitors_group_id_fkey":
		return domain.GroupDoesNotExistError{
			ID: groupID,
		}
	case code == pgerrcode.UniqueViolation && constraint == "monitors_group_id_tribe_id_key":
		return domain.MonitorAlreadyExistsError{
			TribeID: tribeID,
			GroupID: groupID,
		}
	default:
		return err
	}
}