[statistics] Make query builder a bit more OOP

1 files changed, 88 insertions, 0 deletions

diff --git a/modules-available/statistics/inc/hardwarequerycolumn.inc.php b/modules-available/statistics/inc/hardwarequerycolumn.inc.php
new file mode 100644
index 00000000..d073530b
--- /dev/null
+++ b/modules-available/statistics/inc/hardwarequerycolumn.inc.php
@@ -0,0 +1,88 @@
+<?php
+
+class HardwareQueryColumn
+{
+	/** @var int For unique table names in join */
+	private static $id = 0;
+
+	private $global;
+	private $tableAlias;
+	private $virtualColumnName;
+	private $alias;
+	private $conditions = [];
+	private $params = [];
+	private $classId;
+
+	private static function getId(): string
+	{
+		return 't' . ++self::$id;
+	}
+
+	public function __construct(bool $global, string $column, string $alias = null)
+	{
+		$this->classId = ++self::$id;
+		$this->global = $global;
+		$this->tableAlias = self::getId();
+		$this->virtualColumnName = $column;
+		$this->alias = $alias ?? $column;
+	}
+
+	/**
+	 * Add necessary conditions, joins, columns to final SQL arrays. To be called
+	 * from HardwareQuery::buildQuery().
+	 * @param bool $groupConcat whether to add distinct GROUP_CONCAT to column.
+	 */
+	public function generate(array &$joins, array &$columns, array &$params, bool $groupConcat)
+	{
+		if ($this->global) {
+			$srcTable = 'shw';
+			$table = 'statistic_hw_prop';
+			$column = 'hwid';
+		} else {
+			$srcTable = 'mxhw';
+			$table = 'machine_x_hw_prop';
+			$column = 'machinehwid';
+		}
+		$tid = $this->tableAlias;
+		$pid = self::getId();
+		$this->conditions[] = "$srcTable.$column = $tid.$column AND $tid.prop = :$pid";
+		$params[$pid] = $this->virtualColumnName; // value of property column is our virtual column
+		// If we have just one condition, it's the join condition itself. Since we pretend we're just adding
+		// a column to the query, do a left join, so the "column" is NULL if the join doesn't match.
+		// If however any conditions were added to this class via the addCondition() method, do a regular
+		// INNER JOIN, so the result will be empty if the condition doesn't match.
+		$type = count($this->conditions) === 1 ? 'LEFT' : 'INNER';
+		$joins[] = "$type JOIN $table $tid ON (" . implode(' AND ', $this->conditions) . ")";
+		if ($groupConcat) {
+			$columns[] = "Group_Concat(DISTINCT $tid.`value` SEPARATOR ', ') AS `{$this->alias}`";
+		} else {
+			$columns[] = "$tid.`value` AS `{$this->alias}`";
+		}
+		$params += $this->params;
+	}
+
+	/**
+	 * @param string $op Operator (<>=, IN, LIKE)
+	 * @param string|string[]|HardwareQueryColumn $other value to compare with.
+	 * 	Can be a literal, an array (if opererator is IN), or another Column
+	 * @return void
+	 */
+	public function addCondition(string $op, $other)
+	{
+		$valueCol = ($op === '<' || $op === '>' || $op === '<=' || $op === '>=') ? 'numeric' : 'value';
+		if ($other instanceof HardwareQueryColumn) {
+			$cond = "{$this->tableAlias}.`$valueCol` $op {$other->tableAlias}.`$valueCol`";
+			// Don't reference a column of a table that hasn't been joined yet
+			if ($this->classId > $other->classId) {
+				$this->conditions[] = $cond;
+			} else {
+				$other->conditions[] = $cond;
+			}
+		} else {
+			$pid = self::getId();
+			$this->conditions[] = "{$this->tableAlias}.`$valueCol` $op (:$pid)";
+			$this->params[$pid] = $other;
+		}
+	}
+
+}
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