// Package app is the self-hosted, Postgres-backed side of Spread: subscribers,
// users, sessions, the admin CMS, and the customer dashboard. It is imported
// only by the standalone binary (main.go), never by the Vercel function, so
// the public demo stays dependency-light.
package app

import (
	"context"
	_ "embed"
	"fmt"

	"github.com/jackc/pgx/v5/pgxpool"
)

//go:embed schema.sql
var schemaSQL string

// App holds the database pool and shared configuration for all handlers.
type App struct {
	pool         *pgxpool.Pool
	secureCookie bool
	baseURL      string
	mailer       Mailer
}

// Config configures the application. Only DSN is required; the rest have sane
// defaults so the CLI helpers can open with a bare Config.
type Config struct {
	DSN          string
	SecureCookie bool
	BaseURL      string
	Mailer       Mailer
}

// Open connects to Postgres, verifies the connection, and applies the schema.
func Open(ctx context.Context, cfg Config) (*App, error) {
	pool, err := pgxpool.New(ctx, cfg.DSN)
	if err != nil {
		return nil, fmt.Errorf("connect: %w", err)
	}
	if err := pool.Ping(ctx); err != nil {
		pool.Close()
		return nil, fmt.Errorf("ping: %w", err)
	}
	if _, err := pool.Exec(ctx, schemaSQL); err != nil {
		pool.Close()
		return nil, fmt.Errorf("apply schema: %w", err)
	}
	if cfg.Mailer == nil {
		cfg.Mailer = LogMailer{}
	}
	if cfg.BaseURL == "" {
		cfg.BaseURL = "http://localhost:8137"
	}
	return &App{pool: pool, secureCookie: cfg.SecureCookie, baseURL: cfg.BaseURL, mailer: cfg.Mailer}, nil
}

func (a *App) Close() {
	if a.pool != nil {
		a.pool.Close()
	}
}