import pg from 'pg'

const { Pool } = pg
let pool

export function getPool() {
  if (!pool) {
    if (!process.env.DATABASE_URL) throw new Error('DATABASE_URL is required')
    pool = new Pool({
      connectionString: process.env.DATABASE_URL,
      max: 10,
      ssl: process.env.DATABASE_SSL === 'true' ? { rejectUnauthorized: false } : undefined
    })
  }
  return pool
}

export async function initDb() {
  const db = getPool()
  await db.query(`
    CREATE TABLE IF NOT EXISTS templates (
      id text PRIMARY KEY,
      tenant_id text NOT NULL,
      name text NOT NULL,
      type text NOT NULL CHECK (type IN ('email', 'report')),
      status text NOT NULL DEFAULT 'draft',
      draft_document jsonb NOT NULL,
      sample_data jsonb NOT NULL DEFAULT '{}'::jsonb,
      published_version integer,
      created_by text,
      updated_by text,
      created_at timestamptz NOT NULL DEFAULT now(),
      updated_at timestamptz NOT NULL DEFAULT now()
    )
  `)
  await db.query(`
    CREATE TABLE IF NOT EXISTS template_versions (
      id text PRIMARY KEY,
      template_id text NOT NULL REFERENCES templates(id) ON DELETE CASCADE,
      version integer NOT NULL,
      document jsonb NOT NULL,
      sample_data jsonb NOT NULL DEFAULT '{}'::jsonb,
      created_by text,
      created_at timestamptz NOT NULL DEFAULT now(),
      UNIQUE(template_id, version)
    )
  `)
  await db.query(`
    CREATE INDEX IF NOT EXISTS templates_tenant_updated_idx
    ON templates (tenant_id, updated_at DESC)
  `)
}