package bundb

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

	"gitea.dwysokinski.me/twhelp/dcbot/internal/bundb/internal/model"
	"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 Monitor struct {
	db *bun.DB
}

func NewMonitor(db *bun.DB) *Monitor {
	return &Monitor{db: db}
}

func (m *Monitor) Create(ctx context.Context, params domain.CreateMonitorParams) (domain.Monitor, error) {
	groupID, err := uuid.Parse(params.GroupID())
	if err != nil {
		return domain.Monitor{}, domain.GroupDoesNotExistError{
			ID: params.GroupID(),
		}
	}

	monitor := model.Monitor{
		GroupID: groupID,
		TribeID: params.TribeID(),
	}

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

		return domain.Monitor{}, fmt.Errorf(
			"something went wrong while inserting monitor into the db: %w",
			mapCreateMonitorError(err, params),
		)
	}

	return monitor.ToDomain(), nil
}

func (m *Monitor) List(ctx context.Context, groupID string) ([]domain.Monitor, error) {
	if _, err := uuid.Parse(groupID); err != nil {
		return nil, nil
	}

	var monitors []model.Monitor

	if err := m.db.NewSelect().
		Model(&monitors).
		Order("created_at ASC").
		Where("group_id = ?", groupID).
		Scan(ctx); err != nil && !errors.Is(err, sql.ErrNoRows) {
		return nil, fmt.Errorf("couldn't select monitors from the db: %w", err)
	}

	result := make([]domain.Monitor, 0, len(monitors))
	for _, monitor := range monitors {
		result = append(result, monitor.ToDomain())
	}

	return result, nil
}

func (m *Monitor) Get(ctx context.Context, id string) (domain.Monitor, error) {
	if _, err := uuid.Parse(id); err != nil {
		return domain.Monitor{}, domain.MonitorNotFoundError{ID: id}
	}

	var monitor model.Monitor

	err := m.db.NewSelect().
		Model(&monitor).
		Where("id = ?", id).
		Scan(ctx)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return domain.Monitor{}, domain.MonitorNotFoundError{ID: id}
		}
		return domain.Monitor{}, fmt.Errorf("couldn't select monitor from the db (id=%s): %w", id, err)
	}

	return monitor.ToDomain(), nil
}

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

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

	return nil
}

func mapCreateMonitorError(err error, params domain.CreateMonitorParams) 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: params.GroupID(),
		}
	case code == pgerrcode.UniqueViolation && constraint == "monitors_group_id_tribe_id_key":
		return domain.MonitorAlreadyExistsError{
			TribeID: params.TribeID(),
			GroupID: params.GroupID(),
		}
	default:
		return err
	}
}