import { badRequest } from './http-error.js';

export const TARGET_SECONDS = 10;

export function defaultSettings() {
  return {
    intro: { enabled: false, volume: 100 },
    outro: { enabled: false, volume: 100 },
    speedUp: true,
    muteClips: true,
    clipVolume: 100,
    music: { enabled: false, volume: 60 },
    voiceVolume: 100,
    // Pro Clip-Index: Lautstärke des Voice-overs, 0–100
    voiceVolumes: {},
    // Clip-Indizes, die nicht ins Video sollen
    excluded: [],
  };
}

function volume(value, name) {
  if (!Number.isInteger(value) || value < 0 || value > 100) {
    throw badRequest(`${name}: Lautstärke muss zwischen 0 und 100 liegen.`);
  }
  return value;
}

function flag(value, name) {
  if (typeof value !== 'boolean') throw badRequest(`${name}: ungültiger Wert.`);
  return value;
}

function clipIndex(value, clipCount) {
  const index = Number(value);
  if (!Number.isInteger(index) || index < 0 || index >= clipCount) {
    throw badRequest('Unbekannter Clip.');
  }
  return index;
}

// Übernimmt nur bekannte Felder aus patch und prüft jedes; der Rest bleibt.
export function mergeSettings(current, patch, clipCount) {
  if (!patch || typeof patch !== 'object' || Array.isArray(patch)) {
    throw badRequest('Ungültige Einstellungen.');
  }
  const next = structuredClone({ ...defaultSettings(), ...current });

  for (const part of ['intro', 'outro', 'music']) {
    if (patch[part] === undefined) continue;
    const value = patch[part];
    if (!value || typeof value !== 'object') throw badRequest(`${part}: ungültiger Wert.`);
    if (value.enabled !== undefined) next[part].enabled = flag(value.enabled, part);
    if (value.volume !== undefined) next[part].volume = volume(value.volume, part);
  }
  for (const key of ['speedUp', 'muteClips']) {
    if (patch[key] !== undefined) next[key] = flag(patch[key], key);
  }
  for (const key of ['clipVolume', 'voiceVolume']) {
    if (patch[key] !== undefined) next[key] = volume(patch[key], key);
  }
  if (patch.voiceVolumes !== undefined) {
    if (!patch.voiceVolumes || typeof patch.voiceVolumes !== 'object') {
      throw badRequest('voiceVolumes: ungültiger Wert.');
    }
    for (const [key, value] of Object.entries(patch.voiceVolumes)) {
      next.voiceVolumes[clipIndex(key, clipCount)] = volume(value, 'Voice-over');
    }
  }
  if (patch.excluded !== undefined) {
    if (!Array.isArray(patch.excluded)) throw badRequest('excluded: ungültiger Wert.');
    next.excluded = [...new Set(patch.excluded.map((value) => clipIndex(value, clipCount)))].sort(
      (a, b) => a - b,
    );
  }
  return next;
}