import { isVideoId } from './video-id.js';

const PAGES = new Set(['home', 'watch', 'search', 'channel']);
const MAX_TEXT = 300;

export function shouldSave({ views, outlierScore }, { threshold, minViews }) {
  return typeof outlierScore === 'number' && outlierScore >= threshold && views >= minViews;
}

const finiteOrNull = (value) => (typeof value === 'number' && Number.isFinite(value) ? value : null);
const textOrNull = (value) => (typeof value === 'string' && value.trim() ? value.trim().slice(0, MAX_TEXT) : null);
const urlOrNull = (value, prefix) => (typeof value === 'string' && value.startsWith(prefix) ? value : null);

// Validates a message coming from the content script before anything is stored.
export function sanitizeItem(raw) {
  if (!raw || !isVideoId(raw.videoId)) return null;
  const outlierScore = finiteOrNull(raw.outlierScore);
  const views = finiteOrNull(raw.views);
  if (outlierScore === null || outlierScore < 0 || views === null || views < 0) return null;
  const subscribers = finiteOrNull(raw.subscribers);
  return {
    videoId: raw.videoId,
    title: textOrNull(raw.title),
    thumbnailUrl: urlOrNull(raw.thumbnailUrl, 'https://i.ytimg.com/'),
    channelTitle: textOrNull(raw.channelTitle),
    channelUrl: urlOrNull(raw.channelUrl, 'https://www.youtube.com/'),
    subscribers: subscribers !== null && subscribers >= 0 ? subscribers : null,
    views,
    outlierScore: Math.round(outlierScore * 100) / 100,
    isShort: raw.isShort === true,
    page: PAGES.has(raw.page) ? raw.page : 'home',
  };
}

export function buildRecord(item, previous, settings, now = new Date()) {
  if (!previous && !shouldSave(item, settings)) return null;
  const nowIso = now.toISOString();
  return {
    videoId: item.videoId,
    title: item.title ?? previous?.title ?? item.videoId,
    url: `https://www.youtube.com/watch?v=${item.videoId}`,
    thumbnailUrl: item.thumbnailUrl ?? previous?.thumbnailUrl ?? null,
    channelTitle: item.channelTitle ?? previous?.channelTitle ?? null,
    channelUrl: item.channelUrl ?? previous?.channelUrl ?? null,
    subscribers: item.subscribers ?? previous?.subscribers ?? null,
    views: item.views,
    outlierScore: item.outlierScore,
    isShort: item.isShort || previous?.isShort || false,
    foundOn: previous?.foundOn ?? item.page,
    firstSeenAt: previous?.firstSeenAt ?? nowIso,
    updatedAt: nowIso,
  };
}