const MINDSPACE_ASSET_ID_RE = /\/mindspace\/v1\/assets\/([^/?#]+)/i;
const PUBLIC_IMAGE_PATH_RE = /\/public\/images\/([^?#\s"'<>]+)/i;

const IMAGE_URL_LINE_RE = /^\[图片\d+]: (.+)$/;
const IMAGE_URL_LINES_RE = /\n*\[图片\d+]: [^\n]+/g;
const TKMIND_VISION_NOTE_RE = /\n*【TKMind 图片分析结果[\s\S]*$/;

export function extractImageAssetKey(url) {
  const value = String(url ?? '').trim();
  if (!value) return '';
  const assetMatch = value.match(MINDSPACE_ASSET_ID_RE);
  if (assetMatch?.[1]) return `asset:${decodeURIComponent(assetMatch[1])}`;
  const publicMatch = value.match(PUBLIC_IMAGE_PATH_RE);
  if (publicMatch?.[1]) return `public:${decodeURIComponent(publicMatch[1])}`;
  try {
    const parsed = value.startsWith('http://') || value.startsWith('https://')
      ? new URL(value)
      : new URL(value, 'http://local');
    return `path:${parsed.pathname}${parsed.search}`;
  } catch {
    return `raw:${value}`;
  }
}

export function dedupeImageUrlsByAssetKey(urls) {
  const seen = new Set();
  const result = [];
  for (const raw of urls) {
    const url = String(raw ?? '').trim();
    if (!url) continue;
    const key = extractImageAssetKey(url);
    if (seen.has(key)) continue;
    seen.add(key);
    result.push(url);
  }
  return result;
}

export function collectImageUrlsFromMessageContent(content) {
  const urls = [];
  if (!Array.isArray(content)) return urls;
  for (const item of content) {
    if (item?.type === 'image_url' && item.image_url?.url) {
      urls.push(String(item.image_url.url).trim());
      continue;
    }
    if (item?.type !== 'text' || typeof item.text !== 'string') continue;
    for (const line of item.text.split('\n')) {
      const match = line.trim().match(IMAGE_URL_LINE_RE);
      if (match?.[1]) urls.push(match[1].trim());
    }
  }
  return urls;
}

/**
 * Current-turn image URLs: metadata.imageUrls is authoritative when present.
 */
export function extractCurrentTurnImageUrls(userMessage) {
  const fromMetadata = Array.isArray(userMessage?.metadata?.imageUrls)
    ? userMessage.metadata.imageUrls
        .filter((url) => typeof url === 'string' && url.trim())
        .map((url) => url.trim())
    : [];
  if (fromMetadata.length > 0) {
    return dedupeImageUrlsByAssetKey(fromMetadata);
  }
  return dedupeImageUrlsByAssetKey(collectImageUrlsFromMessageContent(userMessage?.content));
}

function stripAgentImageText(text) {
  return String(text ?? '')
    .replace(TKMIND_VISION_NOTE_RE, '')
    .replace(IMAGE_URL_LINES_RE, '')
    .trim();
}

/**
 * Remove image attachments from a persisted user message so later turns cannot reuse them.
 * UI displayText / previewImageUrls are preserved for chat history rendering.
 */
export function scrubUserMessageImageAttachments(message) {
  if (!message || message.role !== 'user') return { message, changed: false };

  const metadata =
    message.metadata && typeof message.metadata === 'object' && !Array.isArray(message.metadata)
      ? { ...message.metadata }
      : {};
  const hadImageMetadata =
    Array.isArray(metadata.imageUrls) && metadata.imageUrls.length > 0
    || Array.isArray(metadata.previewImageUrls) && metadata.previewImageUrls.length > 0;

  if (Array.isArray(metadata.imageUrls) && metadata.imageUrls.length > 0) {
    metadata.archivedImageUrls = metadata.imageUrls;
  }
  if (Array.isArray(metadata.previewImageUrls) && metadata.previewImageUrls.length > 0) {
    metadata.archivedPreviewImageUrls = metadata.previewImageUrls;
  }
  delete metadata.imageUrls;
  delete metadata.previewImageUrls;

  let contentChanged = false;
  const content = Array.isArray(message.content)
    ? message.content.map((item) => {
        if (item?.type !== 'text' || typeof item.text !== 'string') return item;
        const nextText = stripAgentImageText(item.text);
        if (nextText === item.text) return item;
        contentChanged = true;
        return nextText ? { ...item, text: nextText } : null;
      }).filter(Boolean)
    : message.content;

  const displayText =
    typeof metadata.displayText === 'string' ? metadata.displayText : null;
  const changed = hadImageMetadata || contentChanged;
  if (!changed) return { message, changed: false };

  return {
    message: {
      ...message,
      content,
      metadata,
      ...(displayText != null ? {} : {}),
    },
    changed: true,
  };
}

export function scrubConversationHistoricalImageAttachments(conversation, activeMessageId) {
  const activeId = String(activeMessageId ?? '').trim();
  if (!Array.isArray(conversation) || !activeId) {
    return { conversation, changed: false };
  }

  let changed = false;
  const nextConversation = conversation.map((message) => {
    if (message?.role !== 'user') return message;
    if (String(message?.id ?? '').trim() === activeId) return message;
    const scrubbed = scrubUserMessageImageAttachments(message);
    if (scrubbed.changed) changed = true;
    return scrubbed.message;
  });

  return {
    conversation: nextConversation,
    changed,
  };
}

export function buildCurrentTurnImageScopeNote(imageItems) {
  if (!Array.isArray(imageItems) || imageItems.length === 0) return '';

  const lines = imageItems.map((item, index) => {
    const assetKey = extractImageAssetKey(item.rawUrl ?? item.embedUrl ?? '');
    const assetId = assetKey.startsWith('asset:') ? assetKey.slice('asset:'.length) : `图片${index + 1}`;
    return `  ${index + 1}. asset=${assetId}  页面嵌入=${item.embedUrl ?? item.rawUrl ?? ''}`;
  });

  return (
    '【本轮图片主题（硬性）】\n' +
    `- 本轮用户仅上传 ${imageItems.length} 张图片；每次上传都是独立主题，不得与历史轮次混用。\n` +
    `- 用户说「这个图片 / 根据这张图 / 这张」时，只能使用下列本轮附件：\n${lines.join('\n')}\n` +
    '- 对话历史中更早消息里出现过的图片、asset、<img> 路径均已作废，禁止用于本轮任务。\n\n'
  );
}

export const chatImageTurnScopeInternals = {
  IMAGE_URL_LINE_RE,
  TKMIND_VISION_NOTE_RE,
};