let selectedFile = null;

function handleFileSelect(e) {
    const file = e.target.files[0];
    if (!file) return;

    if (file.size > 15 * 1024 * 1024) {
        alert("Файл слишком большой. Максимальный размер: 15 МБ");
        e.target.value = "";
        return;
    }

    selectedFile = file;
    const fileNameEl = document.getElementById("file-name-display");
    const fileSizeEl = document.getElementById("file-size-display");
    const previewContainer = document.getElementById("file-preview-container");

    if (fileNameEl) fileNameEl.innerText = file.name;
    if (fileSizeEl) fileSizeEl.innerText = `(${(file.size / 1024).toFixed(1)} KB)`;
    if (previewContainer) previewContainer.classList.remove("hidden");
}

function clearAttachedFile() {
    selectedFile = null;
    const fileInput = document.getElementById("file-input");
    const previewContainer = document.getElementById("file-preview-container");
    if (fileInput) fileInput.value = "";
    if (previewContainer) previewContainer.classList.add("hidden");
}

async function sendMessage(e) {
    if (e && e.preventDefault) e.preventDefault();

    const input = document.getElementById("user-input");
    const chatWindow = document.getElementById("chat-window");
    const sendBtn = document.getElementById("send-btn");
    
    if (!input || !chatWindow) return;
    const text = input.value.trim();

    if (!text && !selectedFile) return;

    let userDisplayHtml = escapeHtml(text);
    if (selectedFile) {
        userDisplayHtml = `<div class="font-bold border-b border-indigo-400/40 pb-1 mb-1 text-[11px] flex items-center gap-1.5">
            <i class="fa-solid fa-file"></i> ${escapeHtml(selectedFile.name)}
        </div>` + userDisplayHtml;
    }

    const userMsgHtml = `
        <div class="flex justify-end mb-3">
            <div class="bg-indigo-600 text-white rounded-2xl px-4 py-2.5 max-w-2xl text-xs sm:text-sm shadow-sm">
                ${userDisplayHtml}
            </div>
        </div>
    `;
    chatWindow.insertAdjacentHTML("beforeend", userMsgHtml);
    
    input.value = "";
    input.style.height = "auto";
    chatWindow.scrollTop = chatWindow.scrollHeight;

    if (sendBtn) {
        sendBtn.disabled = true;
        sendBtn.classList.add("opacity-50");
    }

    const token = typeof API_TOKEN !== 'undefined' && API_TOKEN ? API_TOKEN : localStorage.getItem("scud_api_auth_token");
    const isGuest = typeof IS_GUEST !== 'undefined' ? IS_GUEST : (localStorage.getItem("scud_is_guest") === "true");

    const endpoint = isGuest ? "/api/v1/chat/guest" : "/api/v1/chat";
    
    // Формируем единый FormData без дублирования
    const formData = new FormData();
    formData.append("session_id", "web_session_main");
    formData.append("message", text || "Проанализируй прикрепленный файл");
    
    if (selectedFile instanceof File) {
        formData.append("file", selectedFile, selectedFile.name);
    }

    const headers = {};
    if (!isGuest && token) {
        headers["Authorization"] = "Bearer " + token;
    }

    try {
        const res = await fetch(endpoint, {
            method: "POST",
            headers: headers,
            body: formData
        });

        if (res.status === 401 && !isGuest) {
            if (typeof logout === 'function') logout();
            return;
        }

        const data = await res.json();
        const assistantTitle = isGuest ? "Локальная нейросеть (Гость)" : "ИИ-Ассистент SCUD Orion AI";
        const replyText = data.reply || "Пустой ответ от нейросети";

        const botMsgHtml = `
            <div class="bg-white border border-slate-200 rounded-2xl p-3.5 shadow-sm max-w-2xl mb-3">
                <p class="text-[11px] font-bold text-indigo-600 uppercase tracking-wider mb-1">
                    <i class="fa-solid fa-robot mr-1"></i> ${assistantTitle}
                </p>
                <p class="text-slate-800 text-xs sm:text-sm whitespace-pre-wrap leading-relaxed">${escapeHtml(replyText)}</p>
            </div>
        `;
        chatWindow.insertAdjacentHTML("beforeend", botMsgHtml);
        chatWindow.scrollTop = chatWindow.scrollHeight;

        clearAttachedFile();

        if (!isGuest && typeof loadTasks === 'function') {
            loadTasks();
        }

    } catch (err) {
        console.error("[Chat Error]", err);
        const errorHtml = `
            <div class="bg-red-50 border border-red-200 rounded-2xl p-3.5 max-w-2xl text-red-700 text-xs sm:text-sm mb-3">
                Ошибка связи с сервером.
            </div>
        `;
        chatWindow.insertAdjacentHTML("beforeend", errorHtml);
        chatWindow.scrollTop = chatWindow.scrollHeight;
    } finally {
        if (sendBtn) {
            sendBtn.disabled = false;
            sendBtn.classList.remove("opacity-50");
        }
    }
}

function escapeHtml(text) {
    if (!text) return "";
    return text
        .replace(/&/g, "&amp;")
        .replace(/</g, "&lt;")
        .replace(/>/g, "&gt;")
        .replace(/"/g, "&quot;")
        .replace(/'/g, "&#039;");
}