"use client";

import { useEffect, useRef, useState } from "react";
import { useConsent } from "../ConsentProvider";
import type { WindowLabels } from "./types";

interface Message {
  id: string;
  text: string;
  from: "user" | "bot";
}

const STORE_ID = "chatSessionId";
const STORE_MESSAGES = "chatMessages";

/**
 * KI-Chat im Fenster. Schickt erst etwas an n8n, wenn der Chatbot im
 * Datenschutz-Banner (oder hier) erlaubt wurde.
 */
export default function ChatBody({ labels }: { labels: WindowLabels }) {
  const { consent, ready, setConsent } = useConsent();
  const allowed = !!consent?.chat;
  const [messages, setMessages] = useState<Message[]>([]);
  const [input, setInput] = useState("");
  const [busy, setBusy] = useState(false);
  const [conversationId, setConversationId] = useState("default");
  const listRef = useRef<HTMLDivElement>(null);
  const inputRef = useRef<HTMLInputElement>(null);

  useEffect(() => {
    if (!allowed) return;
    try {
      let id = localStorage.getItem(STORE_ID);
      if (!id) {
        id = crypto.randomUUID();
        localStorage.setItem(STORE_ID, id);
      }
      setConversationId(id);
      const stored = localStorage.getItem(STORE_MESSAGES);
      const parsed = stored ? (JSON.parse(stored) as { id: string; text: string; sender?: string; from?: string }[]) : [];
      setMessages(
        parsed.length
          ? parsed.map((m) => ({
              id: m.id,
              // Begrüßung immer in der aktuellen Sprache, auch wenn noch eine alte gespeichert ist
              text: m.id === "welcome" ? labels.chat.welcome : m.text,
              from: (m.from ?? m.sender) === "user" ? "user" : "bot",
            }))
          : [{ id: "welcome", text: labels.chat.welcome, from: "bot" }],
      );
    } catch {
      setMessages([{ id: "welcome", text: labels.chat.welcome, from: "bot" }]);
    }
    inputRef.current?.focus({ preventScroll: true });
  }, [allowed, labels.chat.welcome]);

  useEffect(() => {
    if (!allowed || messages.length === 0) return;
    try {
      localStorage.setItem(STORE_MESSAGES, JSON.stringify(messages));
    } catch {}
    listRef.current?.scrollTo({ top: listRef.current.scrollHeight });
  }, [messages, allowed]);

  const send = async () => {
    const text = input.trim();
    if (!text || busy) return;
    const mine: Message = { id: String(Date.now()), text, from: "user" };
    const history = messages.slice(-5).map((m) => ({ role: m.from === "user" ? "user" : "assistant", content: m.text }));
    setMessages((prev) => [...prev, mine]);
    setInput("");
    setBusy(true);
    try {
      const res = await fetch("/api/n8n/chat", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ message: text, conversationId, history }),
      });
      const data = await res.json();
      setMessages((prev) => [...prev, { id: `${Date.now()}-bot`, text: data.reply || labels.chat.error, from: "bot" }]);
    } catch {
      setMessages((prev) => [...prev, { id: `${Date.now()}-bot`, text: labels.chat.error, from: "bot" }]);
    } finally {
      setBusy(false);
    }
  };

  if (!ready) return <div className="h-24 animate-pulse rounded-xl bg-paper-2" aria-hidden="true" />;

  if (!allowed) {
    return (
      <>
        <p className="text-[15px] leading-relaxed">{labels.chat.consent}</p>
        <button
          type="button"
          onClick={() => setConsent({ ...(consent ?? { chat: false }), chat: true })}
          className="w-fit rounded-full bg-ink px-4 py-2.5 text-sm font-semibold text-paper transition-transform duration-150 ease-out active:scale-[0.97]"
        >
          {labels.chat.allow}
        </button>
      </>
    );
  }

  return (
    <div className="flex min-h-[320px] flex-col gap-3">
      <div ref={listRef} className="flex max-h-[46vh] flex-1 flex-col gap-2.5 overflow-y-auto overscroll-contain pr-1" aria-live="polite">
        {messages.map((m) => (
          <div
            key={m.id}
            className={`max-w-[88%] rounded-2xl border-2 border-ink px-3.5 py-2 text-[14.5px] leading-snug ${
              m.from === "user" ? "self-end rounded-br-md bg-ink text-paper" : "self-start rounded-bl-md bg-paper"
            }`}
          >
            {m.text}
          </div>
        ))}
        {busy && (
          <div className="self-start rounded-2xl rounded-bl-md border-2 border-ink px-3.5 py-2 font-mono text-xs" aria-label={labels.chat.thinking}>
            <span className="inline-block animate-pulse">…</span>
          </div>
        )}
      </div>
      <form
        className="flex gap-2"
        onSubmit={(e) => {
          e.preventDefault();
          send();
        }}
      >
        <label htmlFor="chat-input" className="sr-only">
          {labels.chat.placeholder}
        </label>
        <input
          ref={inputRef}
          id="chat-input"
          value={input}
          onChange={(e) => setInput(e.target.value)}
          placeholder={labels.chat.placeholder}
          autoComplete="off"
          className="min-w-0 flex-1 rounded-full border-2 border-ink bg-paper px-4 py-2.5 text-base text-ink placeholder:text-ink/45 focus:outline-none focus-visible:ring-2 focus-visible:ring-signal"
        />
        <button
          type="submit"
          disabled={!input.trim() || busy}
          className="rounded-full bg-ink px-4 text-sm font-semibold text-paper transition-[opacity,transform] duration-150 ease-out active:scale-[0.97] disabled:opacity-40"
        >
          {labels.chat.send}
        </button>
      </form>
      <p className="font-mono text-[11.5px] leading-snug opacity-70">{labels.chat.note}</p>
    </div>
  );
}