master-ai/vibn-frontend/app/api/projects/[projectId]/plan/generate/route.ts

import { NextResponse } from "next/server";
import { authSession } from "@/lib/auth/session-server";
import { query, queryOne } from "@/lib/db-postgres";
import { callVibnChat } from "@/lib/ai/vibn-chat-model";

// Generate a complete PRD, Tech Architecture, and Execution Plan based on the objective

export async function POST(
  req: Request,
  ctx: { params: Promise<{ projectId: string }> }
) {
  const { projectId } = await ctx.params;
  const session = await authSession();
  if (!session?.user?.email) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  const projectRow = await queryOne<{ data: any; slug: string }>(
    `SELECT fs_projects.data, fs_projects.slug FROM fs_projects
     JOIN fs_users u ON u.id = fs_projects.user_id
     WHERE fs_projects.id = $1 AND u.data->>'email' = $2 LIMIT 1`,
    [projectId, session.user.email]
  );
  if (!projectRow) return NextResponse.json({ error: "Project not found" }, { status: 404 });

  const body = await req.json().catch(() => ({}));
  const objective = String(body.objective || projectRow.data?.plan?.vision || "").trim();

  if (!objective) {
    return NextResponse.json({ error: "Objective is required to generate a PRD." }, { status: 400 });
  }

  // We run three sequential LLM calls to construct the complete Spec Kit documentation

  // 1. Generate the Product Spec (User Stories & Requirements)
  const specPrompt = `You are a Principal Product Manager writing a Product Requirements Document (PRD).
Based on the following Objective, generate a structured PRD using Markdown.
DO NOT talk about technology (databases, frameworks, APIs). Focus purely on user value and capabilities.

OBJECTIVE:
${objective}

You MUST follow this exact structure:

## User Scenarios & Testing
List the 3-5 most critical User Stories, prioritized.
### User Story 1 - [Brief Title] (Priority: P1)
[Description]
**Acceptance Scenarios**:
1. **Given** [state], **When** [action], **Then** [outcome]

### User Story 2 - [Brief Title] (Priority: P2)
[Repeat...]

## Functional Requirements
- **FR-001**: System MUST [capability]
- **FR-002**: Users MUST be able to [interaction]

## Success Criteria
- **SC-001**: [Measurable business outcome]`;

  const specResponse = await callVibnChat({
    systemPrompt: specPrompt,
    messages: [{ role: "user", content: "Generate the PRD." }],
    temperature: 0.2
  });
  const specMd = specResponse.text || "Failed to generate PRD.";

  // 2. Generate the Technical Architecture (Plan)
  const planPrompt = `You are a Principal Software Architect.
Based on the following PRD, define the Technical Architecture required to build it.
Your choices must default to: Next.js (App Router), Postgres, Tailwind CSS, NextAuth, and Stripe (if payments).

PRD:
${specMd}

You MUST follow this exact structure:

## Technical Context
- **Language/Framework**: Next.js 15 (App Router), TypeScript
- **Database**: Postgres (via Prisma or raw SQL)
- **Styling**: Tailwind CSS
- **Authentication**: [Decide auth strategy]

## Data Model
List the core database tables and their relationships.
- **[EntityName]**: [fields...]

## File Structure
Provide a high-level file tree representing the required Next.js pages and API routes.
\`\`\`text
src/app/
  page.tsx
  api/
\`\`\``;

  const planResponse = await callVibnChat({
    systemPrompt: planPrompt,
    messages: [{ role: "user", content: "Generate the Technical Architecture." }],
    temperature: 0.1
  });
  const planMd = planResponse.text || "Failed to generate Architecture.";

  // 3. Generate the Execution Plan (Tasks)
  const tasksPrompt = `You are a Technical Project Manager.
Based on the PRD and Technical Architecture, break the implementation down into an atomic, dependency-ordered Task List.
You MUST format each task EXACTLY as a markdown bullet with a checkbox, a phase tag, and a description containing the file paths.

PRD:
${specMd}

ARCHITECTURE:
${planMd}

You MUST follow this exact structure:

## Phase 1: Setup & Foundation
- [ ] [Phase 1] Initialize Next.js project and layout
- [ ] [Phase 1] Setup Postgres database schema

## Phase 2: [User Story 1 Title]
- [ ] [US1] Build API route for [feature]
- [ ] [US1] Build frontend UI component in src/app/[route]/page.tsx

## Phase 3: [User Story 2 Title]
- [ ] [US2] ...`;

  const tasksResponse = await callVibnChat({
    systemPrompt: tasksPrompt,
    messages: [{ role: "user", content: "Generate the Execution Plan tasks." }],
    temperature: 0.1
  });
  const tasksMd = tasksResponse.text || "";

  // 4. Parse the tasks string into the JSON array expected by the DB
  // Extract all `- [ ] [Group] Task description` lines
  const taskLines = tasksMd.match(/- \[[ x]\] \[(.*?)\] (.*)/g) || [];
  const parsedTasks = taskLines.map(line => {
    const match = line.match(/- \[[ x]\] \[(.*?)\] (.*)/);
    if (!match) return null;
    return {
      id: Math.random().toString(36).slice(2, 11),
      title: `[${match[1]}] ${match[2]}`, // Fixed backticks
      description: "",
      status: "open",
      createdAt: new Date().toISOString()
    };
  }).filter(Boolean);

  // 5. Update the Database Plan
  const currentPlan = projectRow.data?.plan || {};
  
  // Save the PRD under decisions (we can render it specially in the UI)
  const newDecisions = [
    { id: "prd_spec", title: "Product Specification", choice: "Auto-generated PRD", why: specMd },
    { id: "prd_arch", title: "Technical Architecture", choice: "Auto-generated Plan", why: planMd }
  ];

  const updatedPlan = {
    ...currentPlan,
    vision: objective,
    tasks: parsedTasks.length > 0 ? parsedTasks : currentPlan.tasks,
    decisions: newDecisions
  };

  await query(
    `UPDATE fs_projects SET data = jsonb_set(data, '{plan}', $2::jsonb) WHERE id = $1`,
    [projectId, JSON.stringify(updatedPlan)]
  );

  return NextResponse.json({ plan: updatedPlan });
}