# Prisma Writer

Generates Prisma schema files from database schema information.

## Overview

The Prisma Writer converts RelSpec's internal database model representation into Prisma schema language (`.prisma` files), complete with models, fields, relationships, and attributes.

## Features

- Generates Prisma schema syntax
- Creates model definitions with proper field types
- Adds Prisma attributes (@id, @unique, @default, etc.)
- Generates relationship fields
- Includes datasource and generator configurations
- Maps table/column names with @map and @@map

## Usage

### Basic Example

```go
package main

import (
    "git.warky.dev/wdevs/relspecgo/pkg/models"
    "git.warky.dev/wdevs/relspecgo/pkg/writers"
    "git.warky.dev/wdevs/relspecgo/pkg/writers/prisma"
)

func main() {
    options := &writers.WriterOptions{
        OutputPath: "schema.prisma",
        Metadata: map[string]interface{}{
            "datasource_provider": "postgresql",
        },
    }

    writer := prisma.NewWriter(options)
    err := writer.WriteDatabase(db)
    if err != nil {
        panic(err)
    }
}
```

### CLI Examples

```bash
# Generate Prisma schema from PostgreSQL database
relspec --input pgsql \
  --conn "postgres://localhost/mydb" \
  --output prisma \
  --out-file schema.prisma

# Convert GORM models to Prisma
relspec --input gorm --in-file models.go --output prisma --out-file schema.prisma

# Convert JSON to Prisma schema
relspec --input json --in-file database.json --output prisma --out-file prisma/schema.prisma
```

## Generated Code Example

```prisma
datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

generator client {
  provider = "prisma-client-js"
}

model User {
  id        Int      @id @default(autoincrement())
  username  String   @unique @db.VarChar(50)
  email     String   @db.VarChar(100)
  bio       String?  @db.Text
  createdAt DateTime @default(now()) @map("created_at")

  posts Post[]

  @@map("users")
}

model Post {
  id      Int     @id @default(autoincrement())
  userId  Int     @map("user_id")
  title   String  @db.VarChar(200)
  content String? @db.Text

  user User @relation(fields: [userId], references: [id], onDelete: Cascade)

  @@map("posts")
}
```

## Supported Prisma Attributes

### Field Attributes
- `@id` - Primary key
- `@unique` - Unique constraint
- `@default()` - Default value
- `@map()` - Column name mapping
- `@db.*` - Database-specific types
- `@relation()` - Relationship definition

### Model Attributes
- `@@map()` - Table name mapping
- `@@unique()` - Composite unique constraints
- `@@index()` - Index definitions
- `@@id()` - Composite primary keys

## Type Mapping

| SQL Type | Prisma Type | Database Type |
|----------|-------------|---------------|
| bigint | Int | @db.BigInt |
| integer | Int | - |
| varchar(n) | String | @db.VarChar(n) |
| text | String | @db.Text |
| boolean | Boolean | - |
| timestamp | DateTime | @db.Timestamp |
| uuid | String | @db.Uuid |
| json | Json | - |

## Notes

- Model names are PascalCase (e.g., `User`, `Post`)
- Field names are camelCase with `@map` for snake_case columns
- Table names use `@@map` when different from model name
- Nullable fields are marked with `?`
- Relationship fields are automatically generated
- Datasource provider defaults to `postgresql`