// Вспомогательная функция для автоматического изменения высоты текстового поля
function updateInputHeight(el) {
    if (!el) return;
    el.style.height = "24px";
    const newHeight = Math.min(el.scrollHeight, 120);
    el.style.height = newHeight + "px";
}

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");
}

// Функция симуляции отправки системной команды по кнопке
function sendQuickAction(actionText) {
    const input = document.getElementById("user-input");
    if (input) {
        input.value = actionText;
        sendMessage();
    }
}

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;

    // Удаляем старые активные плашки кнопок, чтобы не висели предыдущие подтверждения
    document.querySelectorAll('.confirm-action-bar').forEach(el => el.remove());

    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 = "";
    updateInputHeight(input);
    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";
    
    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";

        // Кнопки генерируем СТРОГО если бэкенд вернул флаг data.needs_confirmation === true
        let buttonsHtml = "";
        if (data.needs_confirmation === true) {
            buttonsHtml = `
                <div class="confirm-action-bar mt-3 pt-2.5 border-t border-slate-200 flex items-center justify-end gap-2">
                    <button type="button" onclick="sendQuickAction('отмена')" 
                        class="bg-slate-100 hover:bg-slate-200 active:bg-slate-300 text-slate-700 font-semibold px-3 py-1.5 rounded-xl text-xs transition border border-slate-300 flex items-center gap-1.5 shadow-sm">
                        <i class="fa-solid fa-xmark text-red-500"></i>
                        <span>Отменить</span>
                    </button>
                    <button type="button" onclick="sendQuickAction('подтверждаю')" 
                        class="bg-emerald-600 hover:bg-emerald-700 active:bg-emerald-800 text-white font-semibold px-3.5 py-1.5 rounded-xl text-xs transition flex items-center gap-1.5 shadow-md">
                        <i class="fa-solid fa-check"></i>
                        <span>Подтвердить</span>
                    </button>
                </div>
            `;
        }

        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>
                ${buttonsHtml}
            </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;");
}

document.addEventListener("DOMContentLoaded", () => {
    const input = document.getElementById("user-input");
    const dropZone = document.getElementById("chat-window")?.parentElement;
    const dropOverlay = document.getElementById("drop-overlay");

    if (input) {
        let historyIndex = -1;
        let localHistory = JSON.parse(localStorage.getItem("scud_chat_input_history") || "[]");

        input.addEventListener("keydown", (e) => {
            if (e.key === "Enter" && !e.shiftKey) {
                e.preventDefault();
                const text = input.value.trim();
                if (text) {
                    if (localHistory.length === 0 || localHistory[0] !== text) {
                        localHistory.unshift(text);
                        if (localHistory.length > 50) localHistory.pop();
                        localStorage.setItem("scud_chat_input_history", JSON.stringify(localHistory));
                    }
                    historyIndex = -1;
                }
                sendMessage(e);
                updateInputHeight(input);
                return;
            }

            if (e.key === "ArrowUp") {
                const textBeforeCursor = input.value.substring(0, input.selectionStart);
                const isFirstLine = !textBeforeCursor.includes("\n");

                if (isFirstLine && input.selectionStart === 0 && localHistory.length > 0) {
                    if (historyIndex < localHistory.length - 1) {
                        e.preventDefault();
                        if (historyIndex === -1) {
                            input.dataset.draft = input.value;
                        }
                        historyIndex++;
                        input.value = localHistory[historyIndex];
                        updateInputHeight(input);
                        input.setSelectionRange(input.value.length, input.value.length);
                    }
                }
            }

            if (e.key === "ArrowDown") {
                const textAfterCursor = input.value.substring(input.selectionEnd);
                const isLastLine = !textAfterCursor.includes("\n");

                if (isLastLine && input.selectionEnd === input.value.length && historyIndex >= 0) {
                    e.preventDefault();
                    if (historyIndex > 0) {
                        historyIndex--;
                        input.value = localHistory[historyIndex];
                    } else {
                        historyIndex = -1;
                        input.value = input.dataset.draft || "";
                    }
                    updateInputHeight(input);
                    input.setSelectionRange(input.value.length, input.value.length);
                }
            }
        });
    }

    if (dropZone && dropOverlay) {
        ["dragenter", "dragover", "dragleave", "drop"].forEach(eventName => {
            dropZone.addEventListener(eventName, (e) => {
                e.preventDefault();
                e.stopPropagation();
            }, false);
        });

        ["dragenter", "dragover"].forEach(eventName => {
            dropZone.addEventListener(eventName, () => {
                dropOverlay.classList.remove("hidden");
                dropOverlay.classList.add("flex");
            }, false);
        });

        ["dragleave", "drop"].forEach(eventName => {
            dropZone.addEventListener(eventName, (e) => {
                if (eventName === "drop" || e.target === dropZone || !dropZone.contains(e.relatedTarget)) {
                    dropOverlay.classList.add("hidden");
                    dropOverlay.classList.remove("flex");
                }
            }, false);
        });

        dropZone.addEventListener("drop", (e) => {
            const dt = e.dataTransfer;
            const files = dt.files;

            if (files && files.length > 0) {
                const file = files[0];
                handleFileSelect({ target: { files: [file] } });
                
                const fileInput = document.getElementById("file-input");
                if (fileInput) {
                    const dataTransfer = new DataTransfer();
                    dataTransfer.items.add(file);
                    fileInput.files = dataTransfer.files;
                }
            }
        }, false);
    }
});