# RD Curve AI - Copilot Instructions

You are assisting with "RD Curve AI", a Next.js 16 application for video/image compression researchers to manage datasets and plot Rate-Distortion (RD) curves.

## Tech Stack & Key Libraries
- **Framework:** Next.js 16 (App Router), React 19
- **Database:** PostgreSQL, Drizzle ORM (`lib/schema.ts`, `lib/db.ts`)
- **Auth:** Better-Auth (`lib/auth.ts`, `lib/auth-client.ts`)
- **UI:** Tailwind CSS, shadcn/ui, Recharts (`components/rd-chart.tsx`)
- **Validation:** Zod (`lib/types.ts`)
- **AI:** OpenAI (for data parsing)

## Architecture Overview

### Data Model (`lib/schema.ts`)
The core hierarchy is **Dataset -> Method -> DataPoint**.
- **Dataset:** A collection of methods (e.g., "Kodak Dataset").
- **Method:** A specific algorithm (e.g., "JPEG", "HEVC").
- **DataPoint:** A single result with `bpp` (x-axis) and dynamic `metrics` (y-axis) stored in a `jsonb` column.
- **Metric:** Custom definitions for y-axis values (e.g., "PSNR", "MS-SSIM") with a `mapping_function` string for display transformation.

### Authentication Pattern
- **Server-side:** Use `auth.api.getSession({ headers: await headers() })` in API routes/Server Components.
- **Client-side:** Use `authClient` hooks (e.g., `useSession`).
- **Protection:** Always check `if (!session)` in API routes before sensitive operations.

### API Route Pattern (`app/api/**`)
Follow this pattern for Route Handlers:
1. **Auth Check:** Verify session immediately.
2. **Validation:** Parse request body with Zod schemas from `lib/types.ts`.
3. **DB Operation:** Use Drizzle to query/mutate.
4. **Response:** Return `NextResponse.json`.

## Critical Conventions

### Database & Drizzle
- **Schema:** Define all tables in `lib/schema.ts`.
- **IDs:** Use `uuid` with `.defaultRandom()`.
- **Relations:** Use `drizzle-orm` relations for cleaner queries.
- **JSONB:** Use the `metrics` jsonb column in `data_point` for flexible metric storage.

### Frontend Components
- **UI:** Use `components/ui` (shadcn) for primitives, install new ones with `npx shadcn@latest add <component>`.
- **Charts:** Use `Recharts` in `components/rd-chart.tsx`. Handle the `mapping_function` logic (likely via `lib/safe-eval.ts`) when rendering axes.
- **Icons:** Use `lucide-react`.
- **MCP:** Use `context7` mcp for documentation if needed. Use `shadcn` mcp for UI components. Use `lucide-icons` mcp for searching icons.

### Configuration
- **Env Vars:** Access via `lib/config.ts` (e.g., `CONFIG.OPENAI_API_KEY`), NOT `process.env` directly.
- **Types:** Keep shared Zod schemas and TS interfaces in `lib/types.ts`.

### Language
- All API responses and frontend text must be in English.

## Developer Workflows
- **Migrations:** Run `pnpm db:generate` and `pnpm db:migrate` when changing schema.
- **AI Parsing:** The parsing logic (converting text to JSON) should handle unstructured input and map it to the `data_point` structure.