#909 Add OpenRouter prompt cost calculation

public/index.html

@@ -1750,6 +1750,9 @@
                                 <select id="model_openrouter_select">
                                     <option data-i18n="Connect to the API">-- Connect to the API --</option>
                                 </select>
+                                <small>
+                                    Max prompt cost: <span id="openrouter_max_prompt_cost">Unknown</span> <span id="openrouter_max_prompt_cost_currency">USD</span>
+                                </small>
                             </div>
                             <h4 data-i18n="OpenRouter API Key">OpenRouter API Key</h4>
                             <div>

public/scripts/openai.js

@@ -692,8 +692,30 @@ function getChatCompletionModel() {
     }
 }
 
+function calculateOpenRouterCost() {
+    if (oai_settings.chat_completion_source !== chat_completion_sources.OPENROUTER) {
+        return;
+    }
+
+    let cost = 'Unknown';
+    const model = model_list.find(x => x.id === oai_settings.openrouter_model);
+
+    if (model?.pricing) {
+        const completionCost = Number(model.pricing.completion);
+        const promptCost = Number(model.pricing.prompt);
+        const completionTokens = oai_settings.openai_max_tokens;
+        const promptTokens = (oai_settings.openai_max_context - completionTokens);
+        const totalCost = (completionCost * completionTokens) + (promptCost * promptTokens);
+        if (!isNaN(totalCost)) {
+            cost = totalCost.toFixed(2);
+        }
+    }
+
+    $('#openrouter_max_prompt_cost').text(cost);
+}
+
 function saveModelList(data) {
-    model_list = data.map((model) => ({ id: model.id, context_length: model.context_length }));
+    model_list = data.map((model) => ({ id: model.id, context_length: model.context_length, pricing: model.pricing }));
     model_list.sort((a, b) => a?.id && b?.id && a.id.localeCompare(b.id));
 
     if (oai_settings.chat_completion_source == chat_completion_sources.OPENROUTER) {
@@ -1801,6 +1823,8 @@ async function onModelChange() {
             oai_settings.temp_openai = Math.min(oai_max_temp, oai_settings.temp_openai);
             $('#temp_openai').attr('max', oai_max_temp).val(oai_settings.temp_openai).trigger('input');
         }
+
+        calculateOpenRouterCost();
     }
 
     if (oai_settings.chat_completion_source == chat_completion_sources.CLAUDE) {
@@ -2038,11 +2062,13 @@ $(document).ready(function () {
     $(document).on('input', '#openai_max_context', function () {
         oai_settings.openai_max_context = parseInt($(this).val());
         $('#openai_max_context_counter').text(`${$(this).val()}`);
+        calculateOpenRouterCost();
         saveSettingsDebounced();
     });
 
     $(document).on('input', '#openai_max_tokens', function () {
         oai_settings.openai_max_tokens = parseInt($(this).val());
+        calculateOpenRouterCost();
         saveSettingsDebounced();
     });