export interface DictionaryEntry {
  from: string;
  to: string;
}

export interface DictationSettings {
  spokenPunctuation: boolean;
  removeFillerWords: boolean;
  dictionary: DictionaryEntry[];
}

const SPOKEN_PUNCTUATION: Record<string, string> = {
  comma: ',',
  period: '.',
  'full stop': '.',
  'question mark': '?',
  'exclamation mark': '!',
  'exclamation point': '!',
  'new line': '\n',
  'new paragraph': '\n\n',
  colon: ':',
  semicolon: ';',
  'open quote': '"',
  'close quote': '"',
  hyphen: '-',
  dash: '-',
};

const FILLER_WORDS = ['um', 'uh', 'erm', 'you know', 'like,', 'i mean,'];

export const DEFAULT_DICTATION_SETTINGS: DictationSettings = {
  spokenPunctuation: true,
  removeFillerWords: false,
  dictionary: [
    { from: 'neura vault', to: 'NeuraVault' },
    { from: 'open ai', to: 'OpenAI' },
  ],
};

function applySpokenPunctuation(text: string): string {
  let out = text;
  for (const [phrase, symbol] of Object.entries(SPOKEN_PUNCTUATION)) {
    const re = new RegExp(`\\s*\\b${phrase}\\b\\s*`, 'gi');
    out = out.replace(re, symbol === '\n' || symbol === '\n\n' ? symbol : `${symbol} `);
  }
  return out.replace(/ +([.,!?;:])/g, '$1').replace(/[ \t]+/g, ' ');
}

function removeFillers(text: string): string {
  let out = text;
  for (const filler of FILLER_WORDS) {
    const re = new RegExp(`\\b${filler.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}\\b`, 'gi');
    out = out.replace(re, '');
  }
  return out.replace(/[ \t]+/g, ' ').trim();
}

function applyDictionary(text: string, dictionary: DictionaryEntry[]): string {
  let out = text;
  for (const { from, to } of dictionary) {
    if (!from.trim()) continue;
    const re = new RegExp(`\\b${from.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}\\b`, 'gi');
    out = out.replace(re, to);
  }
  return out;
}

/** Full pipeline applied to each finalized speech segment, in the order dedicated
 * dictation tools apply them: custom vocabulary first, then voice commands, then cleanup. */
export function processSpeechSegment(raw: string, settings: DictationSettings): string {
  let text = raw;
  text = applyDictionary(text, settings.dictionary);
  if (settings.spokenPunctuation) text = applySpokenPunctuation(text);
  if (settings.removeFillerWords) text = removeFillers(text);
  // Capitalize first letter of the segment for readability
  text = text.replace(/^\s*([a-z])/, (m) => m.toUpperCase());
  return text.trim();
}

const STORAGE_KEY = 'neuravault:dictation-settings';

export function loadDictationSettings(): DictationSettings {
  try {
    const raw = localStorage.getItem(STORAGE_KEY);
    if (!raw) return DEFAULT_DICTATION_SETTINGS;
    const parsed = JSON.parse(raw);
    return { ...DEFAULT_DICTATION_SETTINGS, ...parsed };
  } catch {
    return DEFAULT_DICTATION_SETTINGS;
  }
}

export function saveDictationSettings(settings: DictationSettings) {
  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify(settings));
  } catch {
    /* storage unavailable */
  }
}