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,
      template_key text,
      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(`ALTER TABLE templates ADD COLUMN IF NOT EXISTS template_key text`)
  await db.query(`
    UPDATE templates
    SET template_key = 'template-' || substr(replace(id, '-', ''), 1, 12)
    WHERE template_key IS NULL
  `)
  await db.query(`ALTER TABLE templates ALTER COLUMN template_key SET NOT NULL`)

  await db.query(`
    CREATE TABLE IF NOT EXISTS folders (
      id text PRIMARY KEY,
      tenant_id text NOT NULL,
      name text NOT NULL,
      parent_id text REFERENCES folders(id) ON DELETE CASCADE,
      created_by text,
      created_at timestamptz NOT NULL DEFAULT now(),
      updated_at timestamptz NOT NULL DEFAULT now()
    )
  `)
  await db.query(`ALTER TABLE templates ADD COLUMN IF NOT EXISTS folder_id text REFERENCES folders(id) ON DELETE SET NULL`)

  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 TABLE IF NOT EXISTS template_assets (
      id text PRIMARY KEY,
      tenant_id text NOT NULL,
      template_id text NOT NULL REFERENCES templates(id) ON DELETE CASCADE,
      asset_key text NOT NULL,
      filename text NOT NULL,
      mime_type text NOT NULL,
      byte_size integer NOT NULL,
      public_token text NOT NULL UNIQUE,
      data bytea NOT NULL,
      created_at timestamptz NOT NULL DEFAULT now(),
      UNIQUE(template_id, asset_key)
    )
  `)

  await db.query(`
    CREATE TABLE IF NOT EXISTS themes (
      id text PRIMARY KEY,
      tenant_id text NOT NULL,
      name text NOT NULL,
      applies_to text NOT NULL DEFAULT 'all' CHECK (applies_to IN ('all', 'report', 'email')),
      theme jsonb NOT NULL,
      created_by text,
      created_at timestamptz NOT NULL DEFAULT now(),
      updated_at timestamptz NOT NULL DEFAULT now()
    )
  `)

  await db.query(`
    CREATE TABLE IF NOT EXISTS theme_assets (
      id text PRIMARY KEY,
      tenant_id text NOT NULL,
      theme_id text NOT NULL REFERENCES themes(id) ON DELETE CASCADE,
      asset_key text NOT NULL,
      filename text NOT NULL,
      mime_type text NOT NULL,
      byte_size integer NOT NULL,
      public_token text NOT NULL UNIQUE,
      data bytea NOT NULL,
      created_at timestamptz NOT NULL DEFAULT now(),
      UNIQUE(theme_id, asset_key)
    )
  `)

  await db.query(`
    CREATE TABLE IF NOT EXISTS api_keys (
      id text PRIMARY KEY,
      tenant_id text NOT NULL,
      name text NOT NULL,
      key_prefix text NOT NULL,
      key_hash text NOT NULL UNIQUE,
      created_by text,
      created_at timestamptz NOT NULL DEFAULT now(),
      last_used_at timestamptz,
      revoked_at timestamptz
    )
  `)

  await db.query(`
    CREATE INDEX IF NOT EXISTS templates_tenant_updated_idx
    ON templates (tenant_id, updated_at DESC)
  `)
  await db.query(`
    CREATE INDEX IF NOT EXISTS templates_folder_idx
    ON templates (tenant_id, folder_id, updated_at DESC)
  `)
  await db.query(`
    CREATE INDEX IF NOT EXISTS folders_parent_idx
    ON folders (tenant_id, parent_id, name)
  `)
  await db.query(`
    CREATE UNIQUE INDEX IF NOT EXISTS folders_unique_sibling_name_idx
    ON folders (tenant_id, COALESCE(parent_id, ''), lower(name))
  `)
  await db.query(`
    CREATE UNIQUE INDEX IF NOT EXISTS templates_tenant_key_idx
    ON templates (tenant_id, template_key)
  `)
  await db.query(`
    CREATE INDEX IF NOT EXISTS api_keys_tenant_created_idx
    ON api_keys (tenant_id, created_at DESC)
  `)
  await db.query(`
    CREATE INDEX IF NOT EXISTS template_assets_template_idx
    ON template_assets (template_id)
  `)
  await db.query(`
    CREATE INDEX IF NOT EXISTS themes_tenant_created_idx
    ON themes (tenant_id, created_at DESC)
  `)
  await db.query(`
    CREATE INDEX IF NOT EXISTS theme_assets_theme_idx
    ON theme_assets (theme_id)
  `)
}