refactor: split architecture, deduplicate code + add README

apps/api/package.json

@@ -7,7 +7,7 @@
   "scripts": {
     "build": "rimraf dist && npx tsc",
     "start": "node dist/server.js",
-    "test": "NODE_OPTIONS=--experimental-vm-modules jest --runInBand",
+    "test": "node --experimental-vm-modules ../../node_modules/jest/bin/jest.js --runInBand",
     "test:watch": "jest --watch",
     "predev": "npm run build",
     "dev": "concurrently \"npx tsc -w\" \"nodemon --ext js,yml dist/server.js\"",

apps/api/src/modules/ai/controller.ts

@@ -1,8 +1,8 @@
 import type { Request, Response, NextFunction } from "express";
 import { AppError } from "../../middleware/errorHandler.js";
-import { prisma } from "../../prisma/client.js";
 import {
   getAiResponse,
+  getAIHistory as getAIHistoryFromService,
   AiServiceError,
   ensureAiAccessOrThrow,
   getAiAccessStatus,
@@ -19,27 +19,8 @@ export async function getAIHistory(
     if (!userId)
       throw new AppError("Unauthorized: User not found in request", 401);
 
-    const messages = await prisma.message.findMany({
-      where: { userId },
-      orderBy: { created_at: "asc" },
-    });
-
-    const paired = [];
-    for (let i = 0; i < messages.length; i++) {
-      const currentMsg = messages[i];
-      if (currentMsg && currentMsg.role === "user") {
-        const nextMsg = messages[i + 1];
-        paired.push({
-          id: currentMsg.id,
-          prompt: currentMsg.content,
-          result: nextMsg?.role === "assistant" ? nextMsg.content : "",
-          created_at: currentMsg.created_at,
-        });
-        if (nextMsg?.role === "assistant") i++;
-      }
-    }
-
-    return res.json(paired.reverse());
+    const history = await getAIHistoryFromService(userId);
+    return res.json(history);
   } catch (err) {
     next(err);
   }

apps/api/src/modules/ai/service.ts

@@ -15,6 +15,30 @@ Ukrainian → Ukrainian. English → English. NEVER mention the language, NEVER
 NEVER meta-comment. Just answer directly.
 Format rules: plain text only, no markdown, no tables, no bold, no emojis, no bullet points. 2–3 sentences max. Use exact numbers from the data.`;
 
+function truncateData(data: object, maxTokens = 1500): string {
+  const full = JSON.stringify(data);
+  const maxChars = maxTokens * 4;
+
+  if (full.length <= maxChars) return full;
+
+  if (Array.isArray(data)) {
+    const result = [];
+    let totalChars = 0;
+    for (const item of data) {
+      const itemStr = JSON.stringify(item);
+      if (totalChars + itemStr.length > maxChars) break;
+      result.push(item);
+      totalChars += itemStr.length;
+    }
+    return (
+      JSON.stringify(result) +
+      ` /* +${data.length - result.length} more items truncated */`
+    );
+  }
+
+  return full.slice(0, maxChars) + "... [truncated]";
+}
+
 type ServiceAiErrorCode = Exclude<AiErrorCode, "USING_DEFAULT_KEY">;
 
 export type AiAccessTier = "user" | "donor" | "admin";
@@ -157,6 +181,30 @@ export async function incrementAiAnalysisUsage(
   });
 }
 
+export async function getAIHistory(userId: string) {
+  const messages = await prisma.message.findMany({
+    where: { userId },
+    orderBy: { created_at: "asc" },
+  });
+
+  const paired = [];
+  for (let i = 0; i < messages.length; i++) {
+    const currentMsg = messages[i];
+    if (currentMsg && currentMsg.role === "user") {
+      const nextMsg = messages[i + 1];
+      paired.push({
+        id: currentMsg.id,
+        prompt: currentMsg.content,
+        result: nextMsg?.role === "assistant" ? nextMsg.content : "",
+        created_at: currentMsg.created_at,
+      });
+      if (nextMsg?.role === "assistant") i++;
+    }
+  }
+
+  return paired.reverse();
+}
+
 async function callGroq(
   apiKey: string,
   modelToUse: string,
@@ -173,7 +221,10 @@ async function callGroq(
     messages: [
       { role: "system", content: systemContent },
       ...contextMessages,
-      { role: "user", content: `${prompt}\n\nData:\n${JSON.stringify(data)}` },
+      {
+        role: "user",
+        content: `${prompt}\n\nData:\n${truncateData(data, 1500)}`,
+      },
     ],
   });
   return completion;
@@ -195,7 +246,10 @@ async function callGemini(
     messages: [
       { role: "system", content: systemContent },
       ...contextMessages,
-      { role: "user", content: `${prompt}\n\nData:\n${JSON.stringify(data)}` },
+      {
+        role: "user",
+        content: `${prompt}\n\nData:\n${truncateData(data, 4000)}`,
+      },
     ],
   });
   return completion;
@@ -239,22 +293,22 @@ export async function getAiResponse(
   data: object,
   model?: string,
 ) {
+  const activeUserKey = await prisma.userApiKey.findFirst({
+    where: { userId, isActive: true },
+    orderBy: { updatedAt: "desc" },
+  });
+
   const historyMessages = await prisma.message.findMany({
     where: { userId },
     orderBy: { created_at: "desc" },
-    take: CONTEXT_LIMIT,
+    take: activeUserKey?.provider === "GROQ" ? 6 : CONTEXT_LIMIT,
   });
   historyMessages.reverse();
   const contextMessages = historyMessages.map((msg) => ({
     role: msg.role as "user" | "assistant",
     content: msg.content,
   }));
 
-  const activeUserKey = await prisma.userApiKey.findFirst({
-    where: { userId, isActive: true },
-    orderBy: { updatedAt: "desc" },
-  });
-
   if (activeUserKey) {
     try {
       const decrypted = decryptApiKey(activeUserKey.apiKey);
@@ -296,29 +350,46 @@ export async function getAiResponse(
       await saveMessages(userId, prompt, content);
       return { model: completion.model, result: content };
     } catch (err: unknown) {
+      console.error("[AI] Provider error:", {
+        status: (err as { status?: number }).status,
+        code: (err as { code?: string }).code,
+        message: err instanceof Error ? err.message : String(err),
+        userId,
+      });
       const msg = err instanceof Error ? err.message : String(err);
       const status = (err as { status?: number }).status;
-      if (status === 429 || msg.includes("rate_limit")) {
+
+      const code = (err as { code?: string }).code;
+      if (
+        status === 429 ||
+        code === "rate_limit_exceeded" ||
+        msg.includes("rate_limit")
+      ) {
         throw new AiServiceError(
           "USER_KEY_LIMIT",
           "Your API key has reached its rate limit.",
         );
       }
-      if (
-        status === 400 ||
-        status === 401 ||
-        status === 403 ||
-        status === 404
-      ) {
+      if (status === 401 || status === 403) {
         throw new AiServiceError(
           "USER_KEY_INVALID",
-          "Your API key is invalid, unauthorized, or model access is unavailable.",
+          "Your API key is invalid or unauthorized.",
         );
       }
-      throw new AiServiceError(
-        "USER_KEY_INVALID",
-        "Your API key is invalid or expired.",
-      );
+      if (status === 404) {
+        throw new AiServiceError(
+          "USER_KEY_INVALID",
+          "Model not found. Check your selected model.",
+        );
+      }
+      if (status === 400) {
+        throw new AiServiceError(
+          "USER_KEY_INVALID",
+          "Bad request to AI provider.",
+        );
+      }
+      // Network / unknown — не кажемо "invalid key"
+      throw new AiServiceError("USER_KEY_INVALID", `AI provider error: ${msg}`);
     }
   }
 

apps/api/src/modules/donation/service.ts

@@ -1,5 +1,6 @@
 import Stripe from "stripe";
 import { Prisma } from "@prisma/client";
+import type { DonationLeaderboardItem } from "@fintrack/types";
 import { ENV } from "../../config/env.js";
 import { prisma } from "../../prisma/client.js";
 import { AppError } from "../../middleware/errorHandler.js";
@@ -180,14 +181,6 @@ export async function createDonationCheckoutSession(
   };
 }
 
-export interface DonationLeaderboardItem {
-  userId: string;
-  name: string;
-  photoUrl: string | null;
-  totalAmountMinor: number;
-  currency: string;
-}
-
 export async function getDonationLeaderboard(
   limit = 20,
 ): Promise<DonationLeaderboardItem[]> {