const ParameterizedSQL = require('loopback-connector').ParameterizedSQL;

module.exports = Self => {
    Self.remoteMethod('getLeaves', {
        description: 'Returns the first shipped and landed possible for params',
        accessType: '',
        accepts: [{
            arg: 'filter',
            type: 'Object',
            description: 'Filter defining where, order, offset, and limit - must be a JSON-encoded string',
            http: {source: 'query'}
        },
        {
            arg: 'zoneFk',
            type: 'Number',
            required: true,
        },
        {
            arg: 'parentFk',
            type: 'Number',
            default: 1,
            required: false,
        }],
        returns: {
            type: ['object'],
            root: true
        },
        http: {
            path: `/getLeaves`,
            verb: 'GET'
        }
    });

    Self.getLeaves = async(filter, zoneFk, parentFk = 1) => {
        let conn = Self.dataSource.connector;
        let stmts = [];

        stmts.push(new ParameterizedSQL(
            `SELECT lft, rgt, depth + 1 INTO @lft, @rgt, @depth
                FROM zoneTreeview WHERE id = ?`, [parentFk]));

        stmts.push(`DROP TEMPORARY TABLE IF EXISTS tChilds`);

        let stmt = new ParameterizedSQL(
            `CREATE TEMPORARY TABLE tChilds
                ENGINE = MEMORY
                SELECT id, lft, rgt
                    FROM zoneTreeview pt`);
        stmt.merge(conn.makeSuffix(filter));

        if (!filter.where) {
            stmt.merge(`WHERE pt.lft > @lft AND pt.rgt < @rgt
                AND pt.depth = @depth`);
        }

        stmts.push(stmt);

        stmts.push(`DROP TEMPORARY TABLE IF EXISTS tZones`);
        stmts.push(new ParameterizedSQL(
            `CREATE TEMPORARY TABLE tZones
                (INDEX (id))
                ENGINE = MEMORY
                SELECT t.id
                    FROM tChilds t
                        JOIN zoneTreeview zt 
                            ON zt.lft > t.lft AND zt.rgt < t.rgt
                        JOIN zoneIncluded zi
                            ON zi.geoFk = zt.id AND zi.zoneFk = ?
                    GROUP BY t.id`, [zoneFk]));

        const resultIndex = stmts.push(new ParameterizedSQL(
            `SELECT 
                    pt.id, 
                    pt.name,
                    pt.lft, 
                    pt.rgt, 
                    pt.depth, 
                    pt.sons,
                    ti.id IS NOT NULL hasCheckedChilds,
                    zi.geoFk IS NOT NULL AS selected,
                    zi.isIncluded AS excluded
                FROM zoneTreeview pt
                    LEFT JOIN vn.zoneIncluded zi 
                        ON zi.geoFk = pt.id AND zi.zoneFk = ?
                    JOIN tChilds c ON c.id = pt.id
                    LEFT JOIN tZones ti ON ti.id = pt.id
                ORDER BY selected DESC, name`, [zoneFk])) - 1;

        const sql = ParameterizedSQL.join(stmts, ';');
        const result = await Self.rawStmt(sql);

        return result[resultIndex];
    };
};