Implement the choosing system.

js/choosing.js

@@ -0,0 +1,55 @@
+const construct_choices = () => {
+    let choices = document.getElementById("choices").children;
+    let start_of_next_range = 1;
+    let options = [];
+
+    // Construct the array for choosing
+    for (choice of choices) {
+        let name = choice.children[0].value;
+        let weight = parseInt(choice.children[1].value);
+
+        if (Number.isNaN(weight)) {
+            break;
+        };
+
+        options.push({
+            "name": name,
+            "min": start_of_next_range,
+            "max": start_of_next_range + weight - 1
+        });
+        start_of_next_range += weight;
+    };
+
+    return {
+        "choices": options,
+        "max_value": start_of_next_range - 1
+    };
+};
+
+
+const choose_option = () => {
+    let {choices, max_value} = construct_choices();
+
+    // No options, error
+    if (choices.length === 0 && max_value === 0) {
+        document.getElementById("result").innerText = "\nERROR: No Choices to pick from";
+        return;
+    }
+    
+    // Only one option exists, no need to waste time with randomness
+    else if (choices.length === 1) {
+        document.getElementById("result").innerText = choices[0].name
+    };
+
+
+    let chosen_value = Math.round(Math.random() * max_value);
+
+
+    // Find the choice which the randomly chosen number fits within
+    for (choice of choices) {
+        if (choice.min <= chosen_value <= choice.max) {
+            document.getElementById("result").innerText = choice.name;
+            return;
+        };
+    };
+};