/**
 * Neurodivergent-friendly notification messaging system.
 *
 * Encouraging tone, adaptive frequency, forbidden phrases.
 * Pure client-side TS — no backend dependency.
 */

import type { GentleMessage, GentleNotificationConfig, GentleNotificationEngine } from './types.js';

export const FORBIDDEN_PHRASES: readonly string[] = [
  "You haven't",
  'You forgot',
  "Don't forget",
  'You should have',
  "Why didn't you",
  'You missed',
  'You failed',
  'You need to',
] as const;

const DEFAULT_MESSAGES: Record<string, GentleMessage[]> = {
  reminder: [
    {
      title: 'Gentle Reminder',
      body: 'Whenever you are ready, there is something waiting for you.',
      tone: 'encouraging',
    },
    {
      title: 'Quick Note',
      body: 'No rush — just a friendly nudge when the time feels right.',
      tone: 'encouraging',
    },
    {
      title: 'Hey there',
      body: 'Take your time. We will be here when you are ready.',
      tone: 'neutral',
    },
  ],
  progress: [
    {
      title: 'Nice Progress',
      body: 'Look at what you have accomplished — every step matters!',
      tone: 'encouraging',
    },
    {
      title: 'Moving Forward',
      body: 'You are making progress at your own pace. That is perfect.',
      tone: 'encouraging',
    },
  ],
  check_in: [
    {
      title: 'Check In',
      body: 'How are you feeling? Remember, there is no wrong answer.',
      tone: 'encouraging',
    },
    { title: 'Quick Check', body: 'Just checking in — hope you are doing well!', tone: 'neutral' },
  ],
  streak: [
    {
      title: 'Streak Update',
      body: 'Your consistency is impressive — keep it going if it feels right!',
      tone: 'encouraging',
    },
  ],
  idle: [
    {
      title: 'Welcome Back',
      body: 'Great to see you again — no judgment, just glad you are here!',
      tone: 'encouraging',
    },
    {
      title: 'Hi Again',
      body: 'Whenever you are ready to jump back in, we are here.',
      tone: 'neutral',
    },
  ],
};

export function createGentleNotificationEngine(
  initialConfig?: Partial<GentleNotificationConfig>
): GentleNotificationEngine {
  const messagePools: Record<string, GentleMessage[]> = { ...DEFAULT_MESSAGES };

  function getDefaultConfig(): GentleNotificationConfig {
    return {
      maxPerHour: 3,
      tone: 'encouraging',
      adaptiveFrequency: true,
      dismissCount: 0,
      suppressThreshold: 5,
      ...initialConfig,
    };
  }

  function getMessage(type: string, config?: GentleNotificationConfig): GentleMessage {
    const tone = config?.tone ?? 'encouraging';
    const pool = messagePools[type];

    if (!pool || pool.length === 0) {
      return {
        title: 'Hey',
        body: 'Hope you are having a good day!',
        tone,
      };
    }

    // Filter by tone if possible, fallback to any
    const toneFiltered = pool.filter(m => m.tone === tone);
    const candidates = toneFiltered.length > 0 ? toneFiltered : pool;
    const index = Math.floor(Math.random() * candidates.length);
    return candidates[index];
  }

  function shouldSuppress(config: GentleNotificationConfig): boolean {
    if (config.adaptiveFrequency && config.dismissCount >= config.suppressThreshold) {
      return true;
    }
    return false;
  }

  function recordDismissal(config: GentleNotificationConfig): GentleNotificationConfig {
    const newConfig = { ...config, dismissCount: config.dismissCount + 1 };
    if (newConfig.adaptiveFrequency && newConfig.dismissCount >= newConfig.suppressThreshold) {
      newConfig.maxPerHour = Math.max(1, Math.floor(newConfig.maxPerHour / 2));
    }
    return newConfig;
  }

  function resetDismissals(config: GentleNotificationConfig): GentleNotificationConfig {
    return { ...config, dismissCount: 0 };
  }

  function registerMessages(type: string, messages: GentleMessage[]): void {
    messagePools[type] = [...(messagePools[type] ?? []), ...messages];
  }

  function getForbiddenPhrases(): readonly string[] {
    return FORBIDDEN_PHRASES;
  }

  function containsForbiddenPhrase(text: string): boolean {
    const lower = text.toLowerCase();
    return FORBIDDEN_PHRASES.some(phrase => lower.includes(phrase.toLowerCase()));
  }

  return {
    getDefaultConfig,
    getMessage,
    shouldSuppress,
    recordDismissal,
    resetDismissals,
    registerMessages,
    getForbiddenPhrases,
    containsForbiddenPhrase,
  };
}