import type { ReconfigureContext, ReconfigureOptions } from "../types/context";
import { readText, writeText } from "../lib/fs";
import { info, step } from "../lib/log";
import { parseRuntimeEnv, renderRuntimeEnv } from "../config/env";
import { preflight } from "../steps/preflight";
import { generateConfig } from "../steps/config";
import { deploySystemd } from "../steps/systemd";
import { applyFirewall } from "../steps/firewall";
import { writePostInstallEnv } from "../steps/env";
import { smoke } from "../steps/smoke";
import { runVisible } from "../lib/process";

async function backupCurrentState(): Promise<void> {
  await runVisible`mkdir -p /etc/hy2xs/backups`;
  await runVisible`cp -a /etc/hysteria/config.yaml /etc/hy2xs/backups/config.yaml.bak 2>/dev/null || true`;
  await runVisible`cp -a /etc/systemd/system/hy2xs-admin.service /etc/hy2xs/backups/hy2xs-admin.service.bak 2>/dev/null || true`;
  await runVisible`cp -a /etc/systemd/system/hysteria-server.service /etc/hy2xs/backups/hysteria-server.service.bak 2>/dev/null || true`;
  await runVisible`cp -a /etc/nftables.d/hy2xs.nft /etc/hy2xs/backups/hy2xs.nft.bak 2>/dev/null || true`;
}

async function rollbackCurrentState(): Promise<void> {
  await runVisible`cp -a /etc/hy2xs/backups/config.yaml.bak /etc/hysteria/config.yaml 2>/dev/null || true`;
  await runVisible`cp -a /etc/hy2xs/backups/hy2xs-admin.service.bak /etc/systemd/system/hy2xs-admin.service 2>/dev/null || true`;
  await runVisible`cp -a /etc/hy2xs/backups/hysteria-server.service.bak /etc/systemd/system/hysteria-server.service 2>/dev/null || true`;
  await runVisible`cp -a /etc/hy2xs/backups/hy2xs.nft.bak /etc/nftables.d/hy2xs.nft 2>/dev/null || true`;
  await runVisible`systemctl daemon-reload`;
  await runVisible`systemctl restart hysteria-server hy2xs-admin || true`;
}

export async function reconfigure(options: ReconfigureOptions): Promise<void> {
  const configRaw = await readText(options.sourceConfigPath);
  const config = parseRuntimeEnv(configRaw);

  const context: ReconfigureContext & { packageVersion: string; packageBuildId: string; installDate: string; hysteriaAuthPassword: string; hysteriaVersion: string } = {
    options,
    config,
    packageVersion: "reconfigure",
    packageBuildId: "reconfigure",
    installDate: new Date().toISOString(),
    hysteriaAuthPassword: "managed-by-ui-auth",
    hysteriaVersion: "unknown"
  };

  step("preflight");
  await preflight(context);

  if (options.dryRun) {
    info("reconfigure dry-run: validated config and execution graph");
    info(`config source: ${options.sourceConfigPath}`);
    info(`runtime file: ${options.runtimeConfigPath}`);
    info(`ui bind: ${config.uiBindHost}:${config.uiPort}`);
    info(`hysteria bind: ${config.hysteriaBindHost}:${config.hysteriaPort}`);
    info(`public endpoint: ${config.publicHost}:${config.publicPort}`);
    return;
  }

  step("backup");
  await backupCurrentState();

  try {
    step("config generation");
    await generateConfig(context);
    step("systemd units");
    await deploySystemd(context);
    step("firewall");
    await applyFirewall(context);
    step("write env artifacts");
    await writeText(options.runtimeConfigPath, renderRuntimeEnv(config), 0o600);
    await writePostInstallEnv(context);
    step("smoke checks");
    await smoke(context);
  } catch (error) {
    info("reconfigure failed, rollback in progress");
    await rollbackCurrentState();
    throw error;
  }
}