// 负责聊天区域滚动控制的通用方法，解耦 App.vue 中的 DOM 操作

type ScrollContext = {
  getMessagesAreaElement?: () => HTMLElement | null;
  getThinkingContentElement?: (blockId: string) => HTMLElement | null;
  chatToggleScrollLockState?: () => boolean;
  thinkingScrollLocks?: Map<string, boolean>;
  _setScrollingFlag?: (value: boolean) => void;
  autoScrollEnabled?: boolean;
  userScrolling?: boolean;
};

export function scrollToBottom(ctx: ScrollContext) {
  setTimeout(() => {
    const messagesArea = ctx.getMessagesAreaElement?.();
    if (!messagesArea) {
      return;
    }
    if (typeof ctx._setScrollingFlag === 'function') {
      ctx._setScrollingFlag(true);
    }
    messagesArea.scrollTop = messagesArea.scrollHeight;
    setTimeout(() => {
      if (typeof ctx._setScrollingFlag === 'function') {
        ctx._setScrollingFlag(false);
      }
    }, 100);
  }, 50);
}

export function conditionalScrollToBottom(ctx: ScrollContext) {
  if (ctx.autoScrollEnabled === true && ctx.userScrolling === false) {
    scrollToBottom(ctx);
  }
}

export function toggleScrollLock(ctx: ScrollContext) {
  const nextState = ctx.chatToggleScrollLockState?.() ?? false;
  if (nextState) {
    scrollToBottom(ctx);
  }
  return nextState;
}

export function scrollThinkingToBottom(ctx: ScrollContext, blockId: string) {
  if (!blockId) {
    return;
  }
  if (!ctx.thinkingScrollLocks?.get(blockId)) {
    return;
  }
  const el = ctx.getThinkingContentElement?.(blockId);
  if (el) {
    el.scrollTop = el.scrollHeight;
  }
}