<?php

class HardwareQuery
{

	private $id = 0;
	private $joins = [];
	private $where = [];
	private $args = [];
	private $columns = [];

	/**
	 * @param string $type hardware type form HardwareInfo
	 * @param ?string $uuid If set, only return data for specific client
	 */
	public function __construct(string $type, string $uuid = null, $connectedOnly = true)
	{
		if ($connectedOnly) {
			$this->joins['mxhw_join'] = "INNER JOIN machine_x_hw mxhw ON (mxhw.hwid = shw.hwid AND mxhw.disconnecttime = 0)";
		} else {
			$this->joins['mxhw_join'] = "INNER JOIN machine_x_hw mxhw ON (mxhw.hwid = shw.hwid)";
		}
		if ($uuid !== null) {
			$this->where[] = 'mxhw.machineuuid = :uuid';
			$this->args['uuid'] = $uuid;
		}
		$this->where[] = 'shw.hwtype = :hwtype';
		$this->args['hwtype'] = $type;
	}

	private function id(): string
	{
		return 'b' . (++$this->id);
	}

	/**
	 * Add join of a virtual column (hw property) to an arbitrary table and column.
	 * @param bool $global Is the virtual column global or local to machine?
	 * @param string $prop Name of property/virtual column
	 * @param string $jTable Table to join on
	 * @param string $jColumn Column to join on
	 * @param string $condColumn optionally, another column from the joined table to match against $condVal
	 * @param string|array $condVal optionally, a literal, or array of literals, to match foreign column against
	 * @return void
	 */
	public function addForeignJoin(bool $global, string $prop, string $jTable, string $jColumn, string $condColumn = '', $condVal = null)
	{
		if (isset($this->columns["$jTable.$prop"]))
			return;
		if ($global) {
			$srcTable = 'shw';
			$table = 'statistic_hw_prop';
			$column = 'hwid';
		} else {
			$srcTable = 'mxhw';
			$table = 'machine_x_hw_prop';
			$column = 'machinehwid';
		}
		$tid = $this->id();
		$pid = $this->id();
		$this->joins[$prop] = "INNER JOIN $table $tid ON ($srcTable.$column = $tid.$column
			AND $tid.prop = :$pid)";
		$this->args[$pid] = $prop;
		$this->columns[$prop] = "$tid.`value` AS `$prop`";
		$jtid = $this->id();
		$cond = '';
		if (!empty($condColumn)) {
			$vid = $this->id();
			if (is_array($condVal)) {
				$cond = " AND $jtid.`$condColumn` IN (:$vid)";
			} else {
				$cond = " AND $jtid.`$condColumn` = :$vid";
			}
			$this->args[$vid] = $condVal;
		}
		$this->joins[$jTable] = "INNER JOIN $jTable $jtid ON ($jtid.$jColumn = $tid.`value` $cond)";
	}

	public function addMachineWhere(string $column, string $op, $value)
	{
		if (isset($this->columns[$column]))
			return;
		$vid = $this->id();
		$this->joins['machine'] = 'INNER JOIN machine m USING (machineuuid)';
		$this->where[] = "m.$column $op (:$vid)";
		$this->args[$vid] = $value;
		$this->columns[$column] = "m.$column";
	}

	public function addGlobalColumn(string $prop): HardwareQueryColumn
	{
		return $this->addColumn(true, $prop);
	}

	public function addLocalColumn(string $prop): HardwareQueryColumn
	{
		return $this->addColumn(false, $prop);
	}

	public function addColumn(bool $global, string $prop, string $alias = null): HardwareQueryColumn
	{
		return $this->columns[] = new HardwareQueryColumn($global, $prop, $alias);
	}

	/**
	 * Join the machine table and add the given column from it to the SELECT
	 */
	public function addMachineColumn(string $column): void
	{
		if (isset($this->columns[$column]))
			return;
		$this->joins['machine'] = 'INNER JOIN machine m USING (machineuuid)';
		$this->columns[$column] = "m.$column";
	}

	/**
	 * @return false|PDOStatement
	 */
	public function query($groupBy = '')
	{
		return Database::simpleQuery($this->buildQuery($groupBy), $this->args);
	}

	/**
	 * Build query string
	 * @param string[]|string $groupBy Column to group by
	 */
	public function buildQuery($groupBy = ''): string
	{
		if (empty($groupBy)) {
			$groupBy = [];
		} elseif (!is_array($groupBy)) {
			$groupBy = [$groupBy];
		}
		foreach ($groupBy as &$gb) {
			if ($gb[0] !== '`') {
				$gb = "`$gb`";
			}
		}
		$columns = [];
		foreach ($this->columns as $column) {
			if ($column instanceof HardwareQueryColumn) {
				$column->generate($this->joins, $columns, $this->args, $groupBy);
			} else {
				$columns[] = $column;
			}
		}
		$columns[] = 'mxhw.machineuuid';
		$columns[] = 'shw.hwid';
		// TODO: Untangle this implicit magic
		if (empty($groupBy) || $groupBy[0] === 'mxhw.machinehwid') {
			$columns[] = 'mxhw.disconnecttime';
		} else {
			$columns[] = 'Sum(If(mxhw.disconnecttime = 0, 1, 0)) AS connected_count';
		}
		if (!empty($groupBy)) {
			$columns[] = 'Count(*) AS group_count';
			$groupBy = " GROUP BY " . implode(', ', $groupBy);
		} else {
			$groupBy = '';
		}
		return 'SELECT ' . implode(', ', $columns)
			. ' FROM statistic_hw shw '
			. implode(' ', $this->joins)
			. ' WHERE ' . implode(' AND ', $this->where)
			. $groupBy;
	}

}