package postgres

import (
	"database/sql"

	"gardomatic.kleiax.de/internal/storage"
)

// LocationModel stores garden locations in PostgreSQL.
// LocationModel implements storage.LocationModelInterface for PostgreSQL and
// scopes hierarchical locations to their garden.
type LocationModel struct{ DB *sql.DB }

const locationColumns = `l.id, l.garden_id, l.parent_id, l.name, l.description, l.kind, l.area_sqm,
    l.sun_exposure, l.soil_condition, l.soil_reaction, l.attributes, COALESCE('data:'||i.media_type||';base64,'||replace(encode(i.data,'base64'), E'\n', ''), ''), l.image_id, l.created_at, l.updated_at, l.version,
    COALESCE(l.created_by, 0), COALESCE(l.updated_by, 0)`

func scanLocation(s scanner) (storage.Location, error) {
	var location storage.Location
	err := s.Scan(
		&location.ID, &location.GardenID, &location.ParentID, &location.Name,
		&location.Description, &location.Kind, &location.AreaSQM, &location.SunExposure, &location.SoilCondition, &location.SoilReaction,
		&location.Attributes, &location.ImageData, &location.ImageID, &location.CreatedAt, &location.UpdatedAt, &location.Version, &location.CreatedBy, &location.UpdatedBy,
	)
	return location, err
}

// Insert creates a location in its garden.
func (m LocationModel) Insert(location storage.Location) (storage.Location, error) {
	ctx, cancel := contextWithTimeout()
	defer cancel()
	err := m.DB.QueryRowContext(ctx, `
		INSERT INTO locations
			(garden_id, parent_id, name, description, kind, area_sqm, sun_exposure, soil_condition, soil_reaction, attributes, image_data, image_id, created_by, updated_by)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, '', $11, $12, $13)
        RETURNING id, created_at, updated_at, version`,
		location.GardenID, location.ParentID, location.Name, location.Description,
		location.Kind, location.AreaSQM, location.SunExposure, location.SoilCondition, location.SoilReaction, jsonValue(location.Attributes), location.ImageID, nullableUserID(location.CreatedBy), nullableUserID(location.UpdatedBy),
	).Scan(&location.ID, &location.CreatedAt, &location.UpdatedAt, &location.Version)
	if err != nil {
		return storage.Location{}, err
	}
	return location, nil
}

// Get returns a location within its garden.
func (m LocationModel) Get(gardenID, id int) (storage.Location, error) {
	ctx, cancel := contextWithTimeout()
	defer cancel()
	location, err := scanLocation(m.DB.QueryRowContext(ctx, `SELECT `+locationColumns+` FROM locations l LEFT JOIN images i ON i.id=l.image_id WHERE l.garden_id = $1 AND l.id = $2`, gardenID, id))
	if err != nil {
		return storage.Location{}, recordError(err)
	}
	return location, nil
}

// GetAllForGarden lists locations in a garden.
func (m LocationModel) GetAllForGarden(gardenID int) ([]storage.Location, error) {
	ctx, cancel := contextWithTimeout()
	defer cancel()
	rows, err := m.DB.QueryContext(ctx, `SELECT `+locationColumns+`
		FROM locations l LEFT JOIN images i ON i.id=l.image_id WHERE l.garden_id = $1 ORDER BY l.name, l.id`, gardenID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	locations := []storage.Location{}
	for rows.Next() {
		location, err := scanLocation(rows)
		if err != nil {
			return nil, err
		}
		locations = append(locations, location)
	}
	return locations, rows.Err()
}

// Update changes a location using optimistic locking.
func (m LocationModel) Update(gardenID int, location storage.Location) (storage.Location, error) {
	ctx, cancel := contextWithTimeout()
	defer cancel()
	err := m.DB.QueryRowContext(ctx, `
        UPDATE locations SET parent_id = $1, name = $2, description = $3, kind = $4,
		area_sqm = $5, sun_exposure = $6, soil_condition = $7, soil_reaction = $8, attributes = $9, image_data = '', image_id = $10, updated_by = $11,
			updated_at = CURRENT_TIMESTAMP, version = version + 1
		WHERE garden_id = $12 AND id = $13 AND version = $14
        RETURNING updated_at, version`,
		location.ParentID, location.Name, location.Description, location.Kind,
		location.AreaSQM, location.SunExposure, location.SoilCondition, location.SoilReaction, jsonValue(location.Attributes), location.ImageID, nullableUserID(location.UpdatedBy),
		gardenID, location.ID, location.Version,
	).Scan(&location.UpdatedAt, &location.Version)
	if err != nil {
		if err == sql.ErrNoRows {
			return storage.Location{}, storage.ErrEditConflict
		}
		return storage.Location{}, err
	}
	return location, nil
}

// Delete removes a location within its garden.
func (m LocationModel) Delete(gardenID, id int) error {
	ctx, cancel := contextWithTimeout()
	defer cancel()
	result, err := m.DB.ExecContext(ctx, `DELETE FROM locations WHERE garden_id = $1 AND id = $2`, gardenID, id)
	if err != nil {
		return err
	}
	rows, err := result.RowsAffected()
	if err != nil {
		return err
	}
	if rows == 0 {
		return storage.ErrRecordNotFound
	}
	return nil
}