Add offline monthly insights with Ollama

src/lib/insights.ts

@@ -0,0 +1,149 @@
+import type { MonthlyInsight } from "@prisma/client";
+
+import { db } from "@/lib/db";
+import { getCurrentMonthKey } from "@/lib/date";
+import { getDashboardSnapshot } from "@/lib/dashboard";
+import { generateOllamaJson, OllamaUnavailableError } from "@/lib/ollama";
+
+export type InsightResult = {
+  insight: MonthlyInsight;
+  source: "model" | "fallback";
+};
+
+type GeneratedInsightPayload = {
+  summary?: string;
+  recommendations?: string;
+};
+
+function coerceInsightText(value: unknown) {
+  if (typeof value === "string") {
+    return value.trim();
+  }
+
+  if (Array.isArray(value)) {
+    return value
+      .map((item) => (typeof item === "string" ? item.trim() : ""))
+      .filter(Boolean)
+      .join(" ")
+      .trim();
+  }
+
+  if (value && typeof value === "object") {
+    return Object.values(value)
+      .map((item) => (typeof item === "string" ? item.trim() : ""))
+      .filter(Boolean)
+      .join(" ")
+      .trim();
+  }
+
+  return "";
+}
+
+function buildFallbackInsight(month: string, reason: "sparse" | "unavailable") {
+  if (reason === "unavailable") {
+    return {
+      summary: `Local insights are unavailable for ${month} because Ollama or the selected model is not reachable right now.`,
+      recommendations:
+        "Keep tracking manually for now. Once Ollama is running again, regenerate this month to get a private offline summary.",
+    };
+  }
+
+  return {
+    summary: `There is not enough activity in ${month} yet to generate a useful insight summary.`,
+    recommendations:
+      "Add more expenses or paychecks this month, then generate insights again for stronger spending and timing guidance.",
+  };
+}
+
+function buildInsightPrompt(snapshot: Awaited<ReturnType<typeof getDashboardSnapshot>>) {
+  return [
+    "You are a private offline financial summarizer for a single-user expense tracker.",
+    "Return strict JSON with keys summary and recommendations.",
+    "Keep the tone practical, concise, and non-judgmental.",
+    "Focus on spending patterns, category spikes, paycheck timing, and next-month guidance.",
+    `Month: ${snapshot.month}`,
+    `Total expenses cents: ${snapshot.totals.expensesCents}`,
+    `Total paychecks cents: ${snapshot.totals.paychecksCents}`,
+    `Net cash flow cents: ${snapshot.totals.netCashFlowCents}`,
+    `Average daily spend cents: ${snapshot.totals.averageDailySpendCents}`,
+    `Highest category: ${snapshot.comparisons.highestCategory ? `${snapshot.comparisons.highestCategory.category} ${snapshot.comparisons.highestCategory.amountCents}` : "none"}`,
+    `Largest expense: ${snapshot.comparisons.largestExpense ? `${snapshot.comparisons.largestExpense.title} ${snapshot.comparisons.largestExpense.amountCents}` : "none"}`,
+    `Category breakdown: ${JSON.stringify(snapshot.categoryBreakdown)}`,
+    `Recent expenses: ${JSON.stringify(snapshot.recentExpenses)}`,
+    `Daily chart points: ${JSON.stringify(snapshot.chart)}`,
+  ].join("\n");
+}
+
+async function upsertMonthlyInsight(month: string, payload: { summary: string; recommendations: string; inputSnapshot: string }) {
+  const year = Number.parseInt(month.slice(0, 4), 10);
+
+  return db.monthlyInsight.upsert({
+    where: { month },
+    update: {
+      year,
+      summary: payload.summary,
+      recommendations: payload.recommendations,
+      inputSnapshot: payload.inputSnapshot,
+      generatedAt: new Date(),
+    },
+    create: {
+      month,
+      year,
+      summary: payload.summary,
+      recommendations: payload.recommendations,
+      inputSnapshot: payload.inputSnapshot,
+    },
+  });
+}
+
+export async function getStoredMonthlyInsight(month = getCurrentMonthKey()) {
+  return db.monthlyInsight.findUnique({ where: { month } });
+}
+
+export async function generateMonthlyInsight(month = getCurrentMonthKey()): Promise<InsightResult> {
+  const snapshot = await getDashboardSnapshot(month);
+  const totalEvents = snapshot.recentExpenses.length + snapshot.chart.filter((point) => point.paychecksCents > 0).length;
+
+  if (totalEvents < 2) {
+    const fallback = buildFallbackInsight(month, "sparse");
+    const insight = await upsertMonthlyInsight(month, {
+      ...fallback,
+      inputSnapshot: JSON.stringify(snapshot),
+    });
+
+    return { insight, source: "fallback" };
+  }
+
+  try {
+    const generated = await generateOllamaJson<GeneratedInsightPayload>({
+      prompt: buildInsightPrompt(snapshot),
+    });
+
+    const summary = coerceInsightText(generated.summary);
+    const recommendations = coerceInsightText(generated.recommendations);
+
+    if (!summary || !recommendations) {
+      throw new OllamaUnavailableError("The local model returned an incomplete insight response.");
+    }
+
+    const insight = await upsertMonthlyInsight(month, {
+      summary,
+      recommendations,
+      inputSnapshot: JSON.stringify(snapshot),
+    });
+
+    return { insight, source: "model" };
+  } catch (error) {
+    if (!(error instanceof OllamaUnavailableError)) {
+      throw error;
+    }
+
+    const fallback = buildFallbackInsight(month, "unavailable");
+    const insight = await upsertMonthlyInsight(month, {
+      ...fallback,
+      inputSnapshot: JSON.stringify(snapshot),
+    });
+
+    return { insight, source: "fallback" };
+  }
+}