"use client";

import { useState, useCallback, useMemo } from "react";
import { motion, AnimatePresence } from "framer-motion";
import type { ChatMessage, ImageAsset } from "@/lib/types";
import { ImageGrid } from "./image-grid";
import { messageEnter, assistantEnter } from "@/components/ui/motion-presets";

function StreamingLines({ text }: { text: string }) {
  const lines = useMemo(() => text.split("\n"), [text]);
  const total = lines.length;
  return (
    <div className="whitespace-pre-wrap text-sm leading-relaxed">
      {lines.map((line, i) => {
        const fromEnd = total - 1 - i;
        const opacity = fromEnd <= 0 ? 1 : fromEnd === 1 ? 0.85 : fromEnd === 2 ? 0.7 : 0.6;
        return (
          <span key={i} style={{ opacity, transition: "opacity 0.3s ease" }}>
            {line}
            {i < total - 1 && "\n"}
          </span>
        );
      })}
    </div>
  );
}

function CopyButton({ text }: { text: string }) {
  const [copied, setCopied] = useState(false);

  const handleCopy = useCallback(async () => {
    try {
      await navigator.clipboard.writeText(text);
      setCopied(true);
      setTimeout(() => setCopied(false), 1500);
    } catch {
      // fallback
    }
  }, [text]);

  return (
    <button
      onClick={handleCopy}
      className="p-1 rounded-md text-[var(--text-secondary)] hover:text-[var(--accent)]
                 hover:bg-[var(--accent)]/5 transition-colors cursor-pointer btn-hover-lift"
      title="复制文本"
    >
      {copied ? (
        <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="var(--accent)" strokeWidth="2">
          <polyline points="20 6 9 17 4 12" />
        </svg>
      ) : (
        <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
          <rect x="9" y="9" width="13" height="13" rx="2" ry="2" />
          <path d="M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1" />
        </svg>
      )}
    </button>
  );
}

interface ChatMessagesProps {
  messages: ChatMessage[];
  isLoading: boolean;
  streamingText: string;
  streamingImages: ImageAsset[];
  statusText: string;
}

export function ChatMessages({
  messages,
  isLoading,
  streamingText,
  streamingImages,
  statusText,
}: ChatMessagesProps) {
  return (
    <div className="flex-1 overflow-y-auto px-3 md:px-5 py-4 md:py-6 space-y-4 md:space-y-5">
      {messages.map((msg) => (
        <motion.div
          key={msg.id}
          variants={msg.role === "user" ? messageEnter : assistantEnter}
          initial="hidden"
          animate="visible"
          className={`group/msg flex ${msg.role === "user" ? "justify-end" : "justify-start"}`}
        >
          <div className="flex flex-col items-start gap-0.5">
            <div
              className={`max-w-[90vw] md:max-w-[80vw] px-4 md:px-5 py-3 ${
                msg.role === "user"
                  ? "user-bubble bg-gradient-to-r from-[var(--accent)]/8 to-[var(--accent)]/15 text-[var(--text-primary)]"
                  : "rounded-2xl surface-2 text-[var(--text-primary)] border-l-2 border-l-[var(--accent)]/40"
              }`}
            >
              {/* 多图参考（新格式） */}
              {msg.refImageUrls && msg.refImageUrls.length > 0 && (
                <div className="mb-2">
                  <div className="flex flex-wrap gap-1.5">
                    {msg.refImageUrls.map((url, i) => (
                      <img
                        key={i}
                        src={url}
                        alt={`参考图 ${i + 1}`}
                        className="max-w-[120px] max-h-[90px] rounded-lg object-cover
                                   border border-[var(--accent)]/20
                                   shadow-[0_0_10px_rgba(46,139,122,0.08)]"
                      />
                    ))}
                  </div>
                  <span className="text-[10px] text-[var(--accent)]/60 mt-1 block typo-micro" style={{ textTransform: "none" }}>
                    参考图（{msg.refImageUrls.length} 张）
                  </span>
                </div>
              )}
              {/* 兼容旧数据：单图 */}
              {!msg.refImageUrls && msg.refImageUrl && (
                <div className="mb-2">
                  <img
                    src={msg.refImageUrl}
                    alt="参考图"
                    className="max-w-[160px] max-h-[120px] rounded-lg object-cover
                               border border-[var(--accent)]/20
                               shadow-[0_0_10px_rgba(46,139,122,0.08)]"
                  />
                  <span className="text-[10px] text-[var(--accent)]/60 mt-1 block">参考图</span>
                </div>
              )}
              <div className="whitespace-pre-wrap text-sm leading-relaxed">{msg.content}</div>
              {msg.images && msg.images.length > 0 && (
                <>
                  <ImageGrid images={msg.images} />
                  {msg.modelName && (
                    <div className="mt-1.5 text-[10px] text-[var(--accent)]/50 typo-caption">
                      由 {msg.modelName} 生成
                    </div>
                  )}
                </>
              )}
            </div>
            {msg.content && (
              <div className={`opacity-0 group-hover/msg:opacity-100 transition-opacity
                              ${msg.role === "user" ? "mr-1 self-end" : "ml-1"}`}>
                <CopyButton text={msg.content} />
              </div>
            )}
          </div>
        </motion.div>
      ))}

      {/* AI 正在回复（流式） */}
      <AnimatePresence>
        {isLoading && (
          <motion.div
            key="streaming"
            variants={assistantEnter}
            initial="hidden"
            animate="visible"
            exit={{ opacity: 0, transition: { duration: 0.15 } }}
            className="flex justify-start"
          >
            <div className="max-w-[90%] md:max-w-[80%] rounded-2xl px-4 md:px-5 py-3 surface-2 border-l-2 border-l-[var(--accent)]/40">
              {statusText && (
                <div className="text-xs text-[var(--accent)] mb-2 flex items-center gap-2">
                  <span className="inline-block w-2 h-2 rounded-full bg-[var(--accent)] animate-pulse
                                   shadow-[0_0_8px_rgba(46,139,122,0.4)]" />
                  {statusText}
                </div>
              )}
              {streamingText && (
                <StreamingLines text={streamingText} />
              )}
              {streamingImages.length > 0 && <ImageGrid images={streamingImages} />}
              {!streamingText && !statusText && (
                <div className="flex items-end gap-1 h-5">
                  <div className="wave-dot" style={{ animationDelay: "0s" }} />
                  <div className="wave-dot" style={{ animationDelay: "0.15s" }} />
                  <div className="wave-dot" style={{ animationDelay: "0.3s" }} />
                </div>
              )}
            </div>
          </motion.div>
        )}
      </AnimatePresence>
    </div>
  );
}