import { useRef, useState } from "react";
import { View, Text, TextInput, Pressable, ScrollView, StyleSheet } from "react-native";
import { Ionicons } from "@expo/vector-icons";
import * as Speech from "expo-speech";
import { useAuth } from "@/auth";
import { api, ApiError } from "@/api";
import { C } from "@/theme";

interface Msg {
  role: "user" | "assistant";
  text: string;
}

export default function Chat() {
  const { token, logout } = useAuth();
  const [messages, setMessages] = useState<Msg[]>([]);
  const [input, setInput] = useState("");
  const [busy, setBusy] = useState(false);
  const [speak, setSpeak] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const scroll = useRef<ScrollView>(null);

  const send = async (): Promise<void> => {
    const t = input.trim();
    if (!t || busy || !token) return;
    setInput("");
    setError(null);
    setMessages((m) => [...m, { role: "user", text: t }]);
    setBusy(true);
    try {
      const { reply } = await api.chat(token, t);
      setMessages((m) => [...m, { role: "assistant", text: reply }]);
      if (speak) Speech.speak(reply, { language: "fr-FR" });
    } catch (err) {
      if (err instanceof ApiError && err.status === 401) {
        await logout();
        return;
      }
      setError(err instanceof Error ? err.message : "Erreur");
    } finally {
      setBusy(false);
    }
  };

  return (
    <View style={s.wrap}>
      <ScrollView
        ref={scroll}
        style={s.list}
        contentContainerStyle={{ padding: 12, gap: 8 }}
        onContentSizeChange={() => scroll.current?.scrollToEnd({ animated: true })}
      >
        {messages.length === 0 && <Text style={s.muted}>Pose une question à CHLOVA…</Text>}
        {messages.map((m, i) => (
          <View key={i} style={[s.bubble, m.role === "user" ? s.user : s.assistant]}>
            <Text style={s.bubbleText}>{m.text}</Text>
          </View>
        ))}
        {busy && <Text style={s.muted}>CHLOVA réfléchit…</Text>}
        {error && <Text style={s.error}>{error}</Text>}
      </ScrollView>

      <View style={s.bar}>
        <Pressable onPress={() => setSpeak((v) => !v)} style={s.iconBtn} accessibilityLabel="Voix">
          <Ionicons name={speak ? "volume-high" : "volume-mute"} size={20} color={speak ? C.accent : C.muted} />
        </Pressable>
        <TextInput
          style={s.input}
          placeholder="Message…"
          placeholderTextColor={C.muted}
          value={input}
          onChangeText={setInput}
          editable={!busy}
        />
        <Pressable onPress={send} disabled={busy || !input.trim()} style={[s.send, (busy || !input.trim()) && s.disabled]}>
          <Ionicons name="send" size={18} color={C.bg} />
        </Pressable>
      </View>
    </View>
  );
}

const s = StyleSheet.create({
  wrap: { flex: 1, backgroundColor: C.bg },
  list: { flex: 1 },
  muted: { color: C.muted, fontSize: 13 },
  error: { color: C.danger, fontSize: 13 },
  bubble: { maxWidth: "85%", borderRadius: 10, padding: 10, borderWidth: 1 },
  user: { alignSelf: "flex-end", backgroundColor: C.surface2, borderColor: C.accent },
  assistant: { alignSelf: "flex-start", backgroundColor: C.surface, borderColor: C.border },
  bubbleText: { color: C.fg, fontSize: 14 },
  bar: { flexDirection: "row", alignItems: "center", gap: 8, padding: 10, borderTopWidth: 1, borderTopColor: C.border, backgroundColor: C.surface },
  iconBtn: { padding: 8, borderRadius: 8, borderWidth: 1, borderColor: C.border },
  input: { flex: 1, backgroundColor: C.surface2, borderColor: C.border, borderWidth: 1, borderRadius: 8, color: C.fg, paddingHorizontal: 12, paddingVertical: 8 },
  send: { backgroundColor: C.accent, borderRadius: 8, padding: 10 },
  disabled: { opacity: 0.5 },
});