1 files changed, 111 insertions, 0 deletions
diff --git a/server/monitor-conditions/expression.js b/server/monitor-conditions/expression.js
new file mode 100644
index 0000000..1e70369
--- /dev/null
+++ b/server/monitor-conditions/expression.js
@@ -0,0 +1,111 @@
+/**
+ * @readonly
+ * @enum {string}
+ */
+const LOGICAL = {
+    AND: "and",
+    OR: "or",
+};
+
+/**
+ * Recursively processes an array of raw condition objects and populates the given parent group with
+ * corresponding ConditionExpression or ConditionExpressionGroup instances.
+ * @param {Array} conditions Array of raw condition objects, where each object represents either a group or an expression.
+ * @param {ConditionExpressionGroup} parentGroup The parent group to which the instantiated ConditionExpression or ConditionExpressionGroup objects will be added.
+ * @returns {void}
+ */
+function processMonitorConditions(conditions, parentGroup) {
+    conditions.forEach(condition => {
+        const andOr = condition.andOr === LOGICAL.OR ? LOGICAL.OR : LOGICAL.AND;
+
+        if (condition.type === "group") {
+            const group = new ConditionExpressionGroup([], andOr);
+
+            // Recursively process the group's children
+            processMonitorConditions(condition.children, group);
+
+            parentGroup.children.push(group);
+        } else if (condition.type === "expression") {
+            const expression = new ConditionExpression(condition.variable, condition.operator, condition.value, andOr);
+            parentGroup.children.push(expression);
+        }
+    });
+}
+
+class ConditionExpressionGroup {
+    /**
+     * @type {ConditionExpressionGroup[]|ConditionExpression[]} Groups and/or expressions to test
+     */
+    children = [];
+
+    /**
+     * @type {LOGICAL} Connects group result with previous group/expression results
+     */
+    andOr;
+
+    /**
+     * @param {ConditionExpressionGroup[]|ConditionExpression[]} children Groups and/or expressions to test
+     * @param {LOGICAL} andOr Connects group result with previous group/expression results
+     */
+    constructor(children = [], andOr = LOGICAL.AND) {
+        this.children = children;
+        this.andOr = andOr;
+    }
+
+    /**
+     * @param {Monitor} monitor Monitor instance
+     * @returns {ConditionExpressionGroup|null} A ConditionExpressionGroup with the Monitor's conditions
+     */
+    static fromMonitor(monitor) {
+        const conditions = JSON.parse(monitor.conditions);
+        if (conditions.length === 0) {
+            return null;
+        }
+
+        const root = new ConditionExpressionGroup();
+        processMonitorConditions(conditions, root);
+
+        return root;
+    }
+}
+
+class ConditionExpression {
+    /**
+     * @type {string} ID of variable
+     */
+    variable;
+
+    /**
+     * @type {string} ID of operator
+     */
+    operator;
+
+    /**
+     * @type {string} Value to test with the operator
+     */
+    value;
+
+    /**
+     * @type {LOGICAL} Connects expression result with previous group/expression results
+     */
+    andOr;
+
+    /**
+     * @param {string} variable ID of variable to test against
+     * @param {string} operator ID of operator to test the variable with
+     * @param {string} value Value to test with the operator
+     * @param {LOGICAL} andOr Connects expression result with previous group/expression results
+     */
+    constructor(variable, operator, value, andOr = LOGICAL.AND) {
+        this.variable = variable;
+        this.operator = operator;
+        this.value = value;
+        this.andOr = andOr;
+    }
+}
+
+module.exports = {
+    LOGICAL,
+    ConditionExpressionGroup,
+    ConditionExpression,
+};