import type { ReconfigureContext, ReconfigureOptions } from "../types/context";
import { fileExists, readText, writeText } from "../lib/fs";
import { info, setOperationContext, step, stepDone } 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, cancelFirewallRollback, rollbackFirewallNow } from "../steps/firewall";
import { ensureBootstrapAdminSecret, writePostInstallEnv } from "../steps/env";
import { smoke } from "../steps/smoke";
import { runVisible } from "../lib/process";
import { readInstalledHysteriaVersion, readPackageValue } from "../lib/packageMeta";
import { diagnosticsCollect } from "./diagnostics";

const INSTALL_STATE_PATH = "/var/lib/hy2xs/install-state.json";

type InstallState = {
  installed: boolean;
  phase: string;
  version?: string;
  build_id?: string;
  op_id?: string;
  started_at?: string;
  updated_at?: string;
  owned_paths?: string[];
  last_error?: string;
  repair_hint?: string;
};

type ReconfigurePhase =
  | "reconfiguring"
  | "repairing"
  | "config_generated"
  | "units_deployed"
  | "firewall_applied"
  | "runtime_env_written"
  | "smoke_ok"
  | "firewall_connectivity_failure"
  | "smoke_failed"
  | "installed";

function operationKey(context: ReconfigureContext): string {
  return context.installDate;
}

function ownedPaths(context: ReconfigureContext): string[] {
  return [
    context.options.runtimeConfigPath,
    "/etc/hysteria/config.yaml",
    "/etc/hysteria/post-install.env",
    context.config.bootstrapAdminSecretPath,
    "/etc/systemd/system/hy2xs-admin.service",
    "/etc/systemd/system/hysteria-server.service",
    "/etc/nftables.conf",
    "/etc/nftables.d/hy2xs.nft",
    context.config.installDir
  ];
}

async function writeInstallState(state: InstallState): Promise<void> {
  await writeText(INSTALL_STATE_PATH, `${JSON.stringify(state, null, 2)}\n`, 0o644);
  await runVisible`chown root:root ${INSTALL_STATE_PATH}`;
}

async function markPhase(context: ReconfigureContext, phase: ReconfigurePhase, lastError = ""): Promise<void> {
  await writeInstallState({
    installed: phase === "installed",
    phase,
    version: context.packageVersion,
    build_id: context.packageBuildId,
    op_id: operationKey(context),
    started_at: context.installDate,
    updated_at: new Date().toISOString(),
    owned_paths: ownedPaths(context),
    last_error: lastError,
    repair_hint: phase === "installed" ? "" : "run: hy2xs-orchestrator repair --package-dir <path> --config /etc/hy2xs/hy2xs.env"
  });
}

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/hy2xs/hy2xs.env /etc/hy2xs/backups/hy2xs.env.bak 2>/dev/null || true`;
  await runVisible`cp -a /etc/hysteria/post-install.env /etc/hy2xs/backups/post-install.env.bak 2>/dev/null || true`;
  await runVisible`cp -a /etc/nftables.conf /etc/hy2xs/backups/nftables.conf.bak 2>/dev/null || true`;
  await runVisible`cp -a /etc/nftables.d/hy2xs.nft /etc/hy2xs/backups/hy2xs.nft.bak 2>/dev/null || true`;

  await runVisible`test -f /etc/hy2xs/hy2xs.env && echo 1 > /etc/hy2xs/backups/hy2xs.env.existed || rm -f /etc/hy2xs/backups/hy2xs.env.existed`;
  await runVisible`test -f /etc/hysteria/post-install.env && echo 1 > /etc/hy2xs/backups/post-install.env.existed || rm -f /etc/hy2xs/backups/post-install.env.existed`;
  await runVisible`test -f /etc/nftables.conf && echo 1 > /etc/hy2xs/backups/nftables.conf.existed || rm -f /etc/hy2xs/backups/nftables.conf.existed`;
  await runVisible`test -f /etc/nftables.d/hy2xs.nft && echo 1 > /etc/hy2xs/backups/hy2xs.nft.existed || rm -f /etc/hy2xs/backups/hy2xs.nft.existed`;
}

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`if [ -f /etc/hy2xs/backups/hy2xs.env.existed ]; then cp -a /etc/hy2xs/backups/hy2xs.env.bak /etc/hy2xs/hy2xs.env 2>/dev/null || true; else rm -f /etc/hy2xs/hy2xs.env; fi`;
  await runVisible`if [ -f /etc/hy2xs/backups/post-install.env.existed ]; then cp -a /etc/hy2xs/backups/post-install.env.bak /etc/hysteria/post-install.env 2>/dev/null || true; else rm -f /etc/hysteria/post-install.env; fi`;
  await runVisible`if [ -f /etc/hy2xs/backups/nftables.conf.existed ]; then cp -a /etc/hy2xs/backups/nftables.conf.bak /etc/nftables.conf 2>/dev/null || true; fi`;
  await runVisible`if [ -f /etc/hy2xs/backups/hy2xs.nft.existed ]; then cp -a /etc/hy2xs/backups/hy2xs.nft.bak /etc/nftables.d/hy2xs.nft 2>/dev/null || true; else rm -f /etc/nftables.d/hy2xs.nft; fi`;

  await runVisible`nft -f /etc/nftables.conf >/dev/null 2>&1 || true`;
  await runVisible`systemctl daemon-reload`;
  await runVisible`systemctl restart hysteria-server hy2xs-admin || true`;
}

async function ensureInstallStateExists(): Promise<void> {
  if (!(await fileExists(INSTALL_STATE_PATH))) {
    throw new Error(`install state marker is missing: ${INSTALL_STATE_PATH}. Run install first.`);
  }

  const raw = await readText(INSTALL_STATE_PATH);
  let parsed: InstallState;
  try {
    parsed = JSON.parse(raw) as InstallState;
  } catch {
    throw new Error(`invalid install state marker format: ${INSTALL_STATE_PATH}`);
  }
  if (!parsed.installed) {
    throw new Error(`install state marker does not indicate successful installation: ${INSTALL_STATE_PATH}`);
  }
}

async function readInstallState(): Promise<InstallState | null> {
  if (!(await fileExists(INSTALL_STATE_PATH))) {
    return null;
  }
  try {
    return JSON.parse(await readText(INSTALL_STATE_PATH)) as InstallState;
  } catch {
    return null;
  }
}

async function ensureInstallStateForOperation(options: ReconfigureOptions): Promise<void> {
  const state = await readInstallState();
  if (!state) {
    throw new Error(`install state marker is missing: ${INSTALL_STATE_PATH}. Run install first.`);
  }
  if (state.installed) {
    return;
  }
  if (options.allowPartialState) {
    info(`repair mode: proceeding with partial install state (phase=${state.phase ?? "unknown"})`);
    return;
  }
  throw new Error(`install state marker does not indicate successful installation: ${INSTALL_STATE_PATH}`);
}

async function warnBootstrapDrift(nextConfigRaw: string): Promise<void> {
  if (!(await fileExists("/etc/hy2xs/hy2xs.env"))) {
    return;
  }

  const prev = parseRuntimeEnv(await readText("/etc/hy2xs/hy2xs.env"));
  const next = parseRuntimeEnv(nextConfigRaw);
  if (prev.adminInitialPassword !== next.adminInitialPassword || prev.adminConPass !== next.adminConPass) {
    info("warning: Admin bootstrap fields are install-only and will not rotate existing credentials.");
    info("warning: Use a dedicated password rotation flow in application/account layer.");
  }
}

export async function reconfigure(options: ReconfigureOptions): Promise<void> {
  setOperationContext(`reconfigure-${Date.now().toString(36)}`);
  const configRaw = await readText(options.sourceConfigPath);
  const config = parseRuntimeEnv(configRaw);

  const context: ReconfigureContext = {
    mode: "reconfigure",
    options,
    config,
    packageVersion: await readPackageValue(options.packageDir, "package.version", "unknown"),
    packageBuildId: await readPackageValue(options.packageDir, "package.build_id", "unknown"),
    installDate: new Date().toISOString(),
    hysteriaVersion: await readInstalledHysteriaVersion()
  };

  step("preflight");
  await preflight(context);
  stepDone("preflight");
  step("install state marker");
  await ensureInstallStateForOperation(options);
  stepDone("install state marker");
  await warnBootstrapDrift(configRaw);

  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();
  stepDone("backup");

  try {
    await markPhase(context, options.allowPartialState ? "repairing" : "reconfiguring");
    step("config generation");
    await generateConfig(context);
    stepDone("config generation");
    await markPhase(context, "config_generated");
    step("systemd units");
    await deploySystemd(context);
    stepDone("systemd units");
    await markPhase(context, "units_deployed");
    step("firewall");
    await applyFirewall(context);
    stepDone("firewall");
    await markPhase(context, "firewall_applied");
    step("write env artifacts");
    await writeText(options.runtimeConfigPath, renderRuntimeEnv(config), 0o600);
    await runVisible`chown root:root ${options.runtimeConfigPath}`;
    await runVisible`chmod 0600 ${options.runtimeConfigPath}`;
    await ensureBootstrapAdminSecret(context);
    await writePostInstallEnv(context);
    stepDone("write env artifacts");
    await markPhase(context, "runtime_env_written");
    step("smoke checks");
    await smoke(context);
    stepDone("smoke checks");
    await markPhase(context, "smoke_ok");
    step("finalize firewall rollback guard");
    await cancelFirewallRollback(context);
    stepDone("finalize firewall rollback guard");
    await markPhase(context, "installed");

    const finalState = await readInstallState();
    if (!finalState?.installed || finalState.phase !== "installed") {
      throw new Error("deterministic state violation: reconfigure/repair finished without installed phase");
    }
  } catch (error) {
    info("reconfigure failed, rollback in progress");
    const message = error instanceof Error ? error.message : String(error);
    const phase: ReconfigurePhase = /firewall|nft|ssh port check failed/i.test(message)
      ? "firewall_connectivity_failure"
      : "smoke_failed";
    await markPhase(context, phase, message);
    await diagnosticsCollect(options);
    await rollbackFirewallNow(context);
    await rollbackCurrentState();
    throw error;
  }
}

export async function repair(options: ReconfigureOptions): Promise<void> {
  const effective: ReconfigureOptions = {
    ...options,
    dryRun: false,
    apply: true,
    allowPartialState: true,
    skipSmoke: options.skipSmoke ?? false,
    skipServiceStart: options.skipServiceStart ?? false
  };
  await reconfigure(effective);
}