import { existsSync, mkdirSync, readFileSync, writeFileSync, renameSync } from 'node:fs';
import { dirname } from 'node:path';
import { getAgentPath } from './_agent-dir.ts';

export interface McpOnboardingState {
  version: 1;
  sharedConfigHintShown: boolean;
  setupCompleted: boolean;
  lastDiscoveryFingerprint?: string;
}

const DEFAULT_STATE: McpOnboardingState = {
  version: 1,
  sharedConfigHintShown: false,
  setupCompleted: false,
};

export function getOnboardingStatePath(): string {
  return getAgentPath('mcp-onboarding.json');
}

export function loadOnboardingState(): McpOnboardingState {
  const path = getOnboardingStatePath();

  if (!existsSync(path)) {
    return { ...DEFAULT_STATE };
  }

  try {
    const raw = JSON.parse(readFileSync(path, 'utf-8')) as Partial<McpOnboardingState>;

    if (!raw || typeof raw !== 'object') {
      return { ...DEFAULT_STATE };
    }

    return {
      version: 1,
      sharedConfigHintShown: raw.sharedConfigHintShown === true,
      setupCompleted: raw.setupCompleted === true,
      lastDiscoveryFingerprint:
        typeof raw.lastDiscoveryFingerprint === 'string' ? raw.lastDiscoveryFingerprint : undefined,
    };
  } catch {
    return { ...DEFAULT_STATE };
  }
}

export function saveOnboardingState(state: McpOnboardingState): void {
  const path = getOnboardingStatePath();

  mkdirSync(dirname(path), { recursive: true });
  const tmpPath = `${path}.${process.pid}.tmp`;

  writeFileSync(tmpPath, `${JSON.stringify(state, null, 2)}\n`, 'utf-8');
  renameSync(tmpPath, path);
}

export function updateOnboardingState(updater: (state: McpOnboardingState) => McpOnboardingState): McpOnboardingState {
  const next = updater(loadOnboardingState());

  saveOnboardingState(next);

  return next;
}

export function markSharedConfigHintShown(fingerprint?: string): McpOnboardingState {
  return updateOnboardingState((state) => ({
    ...state,
    sharedConfigHintShown: true,
    lastDiscoveryFingerprint: fingerprint ?? state.lastDiscoveryFingerprint,
  }));
}

export function markSetupCompleted(fingerprint?: string): McpOnboardingState {
  return updateOnboardingState((state) => ({
    ...state,
    setupCompleted: true,
    lastDiscoveryFingerprint: fingerprint ?? state.lastDiscoveryFingerprint,
  }));
}