import type { PlatformDb } from "./platform_db.ts";
import { config } from "./config.ts";

export type SmtpSettings = {
  host: string;
  port: number;
  username: string;
  password: string;
  from_address: string;
  enabled: boolean;
  updated_at?: string;
};

export type SmtpPublic = {
  host: string;
  port: number;
  username: string;
  from_address: string;
  enabled: boolean;
  configured: boolean;
  has_password: boolean;
  updated_at: string | null;
  source: "db" | "env" | "none";
};

type SmtpRow = {
  host: string;
  port: number;
  username: string;
  password: string;
  from_address: string;
  enabled: number;
  updated_at: string;
};

function trim(v: unknown): string {
  return (v ?? "").toString().trim();
}

function fromEnv(): SmtpSettings {
  return {
    host: config.smtpHost,
    port: config.smtpPort || 587,
    username: config.smtpUser,
    password: config.smtpPass,
    from_address: config.smtpFrom,
    enabled: Boolean(config.smtpHost && config.smtpFrom),
  };
}

function readRow(platformDb: PlatformDb): SmtpRow | undefined {
  try {
    return platformDb.prepare(
      `SELECT host, port, username, password, from_address, enabled, updated_at
       FROM smtp_settings WHERE id = 1`,
    ).get() as SmtpRow | undefined;
  } catch {
    return undefined;
  }
}

/** Config efectiva: fila en platform.db si hay host; si no, variables de entorno. */
export function resolveSmtp(platformDb: PlatformDb): SmtpSettings & { source: "db" | "env" | "none" } {
  const row = readRow(platformDb);
  if (row && trim(row.host)) {
    return {
      host: trim(row.host),
      port: Number(row.port) || 587,
      username: trim(row.username),
      password: row.password ?? "",
      from_address: trim(row.from_address) || config.smtpFrom,
      enabled: Number(row.enabled) === 1,
      updated_at: row.updated_at,
      source: "db",
    };
  }
  const env = fromEnv();
  if (env.host) return { ...env, source: "env" };
  return { ...env, enabled: false, source: "none" };
}

export function smtpConfigured(platformDb: PlatformDb): boolean {
  const s = resolveSmtp(platformDb);
  return s.enabled && Boolean(s.host && s.from_address);
}

export function smtpPublicView(platformDb: PlatformDb): SmtpPublic {
  const s = resolveSmtp(platformDb);
  return {
    host: s.host,
    port: s.port,
    username: s.username,
    from_address: s.from_address,
    enabled: s.enabled,
    configured: smtpConfigured(platformDb),
    has_password: Boolean(s.password),
    updated_at: s.updated_at ?? null,
    source: s.source,
  };
}

export type SaveSmtpInput = {
  host?: string;
  port?: number | string;
  username?: string;
  password?: string;
  from_address?: string;
  enabled?: boolean;
  /** Si true y password vacío, conserva la contraseña actual. */
  keep_password?: boolean;
};

function looksLikeEmailFrom(value: string): boolean {
  // Acepta "user@dom.com" o "Nombre <user@dom.com>"
  return /(?:^|<)[^\s<>@]+@[^\s<>@]+\.[^\s<>@]+(?:>|$)/.test(value);
}

export function saveSmtpSettings(
  platformDb: PlatformDb,
  input: SaveSmtpInput,
): { error?: string; settings?: SmtpPublic } {
  const host = trim(input.host);
  const fromAddress = trim(input.from_address);
  const username = trim(input.username);
  const port = Number(input.port ?? 587);
  if (!Number.isFinite(port) || port < 1 || port > 65535) {
    return { error: "Puerto SMTP inválido" };
  }

  const enabled = input.enabled !== false;
  if (enabled && !host) return { error: "Host SMTP obligatorio si está habilitado" };
  if (enabled && !fromAddress) return { error: "Remitente (From) obligatorio si está habilitado" };
  if (enabled && fromAddress && !looksLikeEmailFrom(fromAddress)) {
    return {
      error: 'Remitente inválido. Use un correo, ej. PANELS <noreply@tudominio.com>',
    };
  }

  const current = readRow(platformDb);
  let password = input.password ?? "";
  if ((input.keep_password || password === "") && current?.password) {
    password = current.password;
  }

  platformDb.prepare(
    `INSERT INTO smtp_settings (id, host, port, username, password, from_address, enabled, updated_at)
     VALUES (1, ?, ?, ?, ?, ?, ?, datetime('now'))
     ON CONFLICT(id) DO UPDATE SET
       host = excluded.host,
       port = excluded.port,
       username = excluded.username,
       password = excluded.password,
       from_address = excluded.from_address,
       enabled = excluded.enabled,
       updated_at = datetime('now')`,
  ).run(host, port, username, password, fromAddress, enabled ? 1 : 0);

  return { settings: smtpPublicView(platformDb) };
}