// src/AssistantMessage.jsx
import React, { useState, useEffect } from "react";
import ReactMarkdown from "react-markdown";
import remarkGfm from "remark-gfm";
import remarkMath from "remark-math";
import rehypeKatex from "rehype-katex";

// Prism.js per syntax highlight
import Prism from "prismjs";
import "prismjs/themes/prism.css";

// Linguaggi base
import "prismjs/components/prism-sql";
import "prismjs/components/prism-javascript";
import "prismjs/components/prism-css";
import "prismjs/components/prism-json";
import "prismjs/components/prism-markdown";
import "prismjs/components/prism-csharp";
import "prismjs/components/prism-lua";
import "prismjs/components/prism-c";
import "prismjs/components/prism-cpp";
import "prismjs/components/prism-python";
import "prismjs/components/prism-basic";
import "prismjs/components/prism-javascript";

// Aggiungo alias "vb" che punta a "vbnet"
Prism.languages.vb = Prism.languages.vbnet;

export default function AssistantMessage({
  content,
  theme,
  timestamp,
  startedAt,
  endedAt,
  isFinal
}) {
  const [showThink, setShowThink] = useState(false);
  const [fadeOut, setFadeOut] = useState(false);

  const ts = timestamp ?? endedAt ?? startedAt;

  const thinkMatch = content?.match(/<think>([\s\S]*?)<\/think>/i);
  const thinkContent = thinkMatch ? thinkMatch[1].trim() : null;

  const isComplete = isFinal || Boolean(timestamp || endedAt);

  const visibleContent = isComplete
    ? content?.replace(/<think>[\s\S]*?<\/think>/i, "").trim()
    : content;

  useEffect(() => {
    if (thinkContent && !isComplete) {
      setShowThink(true);
      setFadeOut(false);
    }
    if (thinkContent && isComplete) {
      setFadeOut(true);
      const timer = setTimeout(() => setShowThink(false), 600);
      return () => clearTimeout(timer);
    }
  }, [thinkContent, isComplete]);

  return (
    <div className="mb-2 text-start">
      <div
        className={`d-inline-block p-2 rounded ${theme.assistantBg}`}
        style={{ maxWidth: "75%" }}
      >
        {showThink && (
          <div
            className={`think-block${fadeOut ? " fade-out" : ""}`}
            style={{
              fontStyle: "italic",
              opacity: 0.7,
              marginBottom: "0.5rem",
              whiteSpace: "pre-wrap"
            }}
          >
            🤔 {thinkContent}
          </div>
        )}

        <ReactMarkdown
          remarkPlugins={[remarkGfm, remarkMath]}
          rehypePlugins={[rehypeKatex]}
          components={{
            table: (props) => (
              <table className="table table-sm table-bordered" {...props} />
            ),
            th: (props) => <th className="bg-light" {...props} />,
            code: CodeWithCopy
          }}
        >
          {visibleContent}
        </ReactMarkdown>
      </div>
      {ts != null && (
        <div
          style={{
            fontSize: "0.75rem",
            color: "#666",
            marginTop: "0.2rem",
            marginLeft: "0.25rem"
          }}
        >
          {formatDateTime(ts)}
        </div>
      )}
    </div>
  );
}

function CodeWithCopy({ inline, className = "", children, ...props }) {
  const [copied, setCopied] = useState(false);
  const codeText = String(children).replace(/\n$/, "");
  const isFencedBlock = !inline && /^language-/.test(className);

  // Evidenziazione con Prism
  useEffect(() => {
    if (isFencedBlock) {
      Prism.highlightAll();
    }
  }, [codeText, isFencedBlock]);

  if (!isFencedBlock) {
    return (
      <code className={className} {...props}>
        {children}
      </code>
    );
  }

  const handleCopy = async () => {
    try {
      await navigator.clipboard.writeText(codeText);
      setCopied(true);
      setTimeout(() => setCopied(false), 1500);
    } catch (err) {
      console.error("Copy failed", err);
    }
  };

  return (
    <div style={{ position: "relative" }}>
      <pre className={className} {...props} style={{ paddingRight: "2rem" }}>
        <code className={className}>{codeText}</code>
      </pre>
      <button
        onClick={handleCopy}
        style={{
          position: "absolute",
          top: "0.25rem",
          right: "0.25rem",
          border: "none",
          background: "transparent",
          cursor: "pointer"
        }}
        className="btn-copy"
        title="Copy to clipboard"
      >
        📋
      </button>
      {copied && (
        <span
          style={{
            position: "absolute",
            top: "0.25rem",
            right: "2rem",
            fontSize: "0.8rem",
            color: "green"
          }}
        >
          Copied!
        </span>
      )}
    </div>
  );
}

function formatDateTime(dateTime) {
  const date = dateTime instanceof Date ? dateTime : new Date(dateTime);
  if (Number.isNaN(date.getTime())) return String(dateTime);
  return date.toLocaleString(undefined, {
    year: "numeric",
    month: "short",
    day: "numeric",
    hour: "2-digit",
    minute: "2-digit",
    second: "2-digit"
  });
}