import { ChatInput } from '@/components/chat/ChatInput';
import { EmptyState } from '@/components/chat/EmptyState';
import { MessageList } from '@/components/chat/MessageList';
import { OfflineBanner } from '@/components/chat/OfflineBanner';
import { useLMStudio } from '@/hooks/useLMStudio';
import { useThemeColor } from '@/hooks/useThemeColor';
import { useAppStore } from '@/store/useAppStore';
import React, { useCallback } from 'react';
import { KeyboardAvoidingView, Platform, StyleSheet } from 'react-native';

export default function ChatScreen() {
    const colors = useThemeColor(); // Dynamic theme
    const messages = useAppStore(state => state.messages);
    const editingMessageId = useAppStore(state => state.editingMessageId);
    const setEditingMessageId = useAppStore(state => state.setEditingMessageId);
    const deleteMessagesAfter = useAppStore(state => state.deleteMessagesAfter);
    const deleteMessage = useAppStore(state => state.deleteMessage);
    const editMessage = useAppStore(state => state.editMessage);
    const { sendMessage, stopStreaming, regenerateResponse, isStreaming, isConnected } = useLMStudio();

    // Find the editing message content
    const editingMessage = editingMessageId
        ? messages.find(m => m.id === editingMessageId)
        : null;

    const handleSend = useCallback((text: string) => {
        if (editingMessageId && editingMessage) {
            editMessage(editingMessageId, text);
            deleteMessagesAfter(editingMessageId);
            setEditingMessageId(null);
            // The edited message is now the last one, so regenerating answers it.
            regenerateResponse();
        } else {
            sendMessage(text);
        }
    }, [editingMessageId, editingMessage, editMessage, deleteMessagesAfter, setEditingMessageId, regenerateResponse, sendMessage]);

    const handleEdit = useCallback((id: string) => setEditingMessageId(id), [setEditingMessageId]);
    const handleCancelEdit = useCallback(() => setEditingMessageId(null), [setEditingMessageId]);
    const handleDelete = useCallback((id: string) => deleteMessage(id), [deleteMessage]);

    return (
        <KeyboardAvoidingView
            style={[styles.container, { backgroundColor: colors.backgroundColor }]}
            behavior={Platform.OS === 'ios' ? 'padding' : undefined}
            keyboardVerticalOffset={Platform.OS === 'ios' ? 90 : 0}
        >
            {!isConnected && <OfflineBanner />}

            {messages.length === 0 ? (
                <EmptyState onSelectPrompt={sendMessage} />
            ) : (
                <MessageList
                    messages={messages}
                    isStreaming={isStreaming}
                    onEdit={handleEdit}
                    onDelete={handleDelete}
                    onRegenerate={regenerateResponse}
                />
            )}

            <ChatInput
                onSend={handleSend}
                onStop={stopStreaming}
                isLoading={isStreaming}
                editingText={editingMessage?.content ?? null}
                onCancelEdit={handleCancelEdit}
            />
        </KeyboardAvoidingView>
    );
}

const styles = StyleSheet.create({
    container: {
        flex: 1,
    },
});