document.addEventListener("DOMContentLoaded", () => {
    // --- DOM Element Selection ---
    const generateBtn = document.getElementById("generate-btn");
    const saveVideoBtn = document.getElementById("save-video-btn");
    const soundToggleBtn = document.getElementById("sound-toggle-btn");
    const loader = document.getElementById("loader");
    const errorContainer = document.getElementById("error-container");
    const placeholder = document.querySelector(".video-container .placeholder");

    // Form Inputs
    const apiKeyInput = document.getElementById("api-key");
    const promptInput = document.getElementById("prompt");
    const negativePromptInput = document.getElementById("negative-prompt");
    const modelSelect = document.getElementById("model");
    const aspectRatioSelect = document.getElementById("aspect-ratio");
    const resolutionSelect = document.getElementById("resolution");
    const personGenSelect = document.getElementById("person-generation");
    const seedInput = document.getElementById("seed");
    const sampleCountInput = document.getElementById("sample-count");
    const durationInput = document.getElementById("duration");
    const generateAudioSwitch = document.getElementById("generate-audio");
    const threadCountInput = document.getElementById("thread-count");
    const enhancePromptSwitch = document.getElementById("enhance-prompt");
    const imagePromptInput = document.getElementById("image-prompt");
    const videoPromptInput = document.getElementById("video-prompt");
    const imageProcessModeSelect = document.getElementById("image-process-mode");
    const imageFillColorGroup = document.getElementById("image-fill-color-group");
    const imageFillColorPicker = document.getElementById("image-fill-color-picker");
    const imageFillColorInput = document.getElementById("image-fill-color");
    
    // Carousel Elements
    const videoCarousel = document.getElementById("video-carousel");
    const prevBtn = document.getElementById("prev-btn");
    const nextBtn = document.getElementById("next-btn");
    const carouselDots = document.getElementById("carousel-dots");

    // Prompt Saving Elements
    const savePromptBtn = document.getElementById("save-prompt-btn");
    const savedPromptsToggle = document.getElementById("saved-prompts-toggle");
    const savedPromptsList = document.getElementById("saved-prompts-list");

   // Key Saving Elements
   const saveKeyBtn = document.getElementById("save-key-btn");
   const savedKeysToggle = document.getElementById("saved-keys-toggle");
   const savedKeysList = document.getElementById("saved-keys-list");

    // --- State ---
    let currentIndex = 0;
    let videoItems = [];
    const SETTINGS_KEY = 'veoGeneratorSettings';
    let currentPasteTarget = null; // 'image' or 'video'
    let savedVideos = []; // To track URLs of saved videos
    const SAVED_PROMPTS_KEY = 'veoGeneratorSavedPrompts';
    const SAVED_KEYS_KEY = 'veoGeneratorSavedKeys';
    const SOUND_SETTINGS_KEY = 'veoGeneratorSoundEnabled';
    let soundEnabled = false; // Default to disabled

   const PRESET_KEYS = [];

    // --- Notification Sound ---
    function playNotificationSound() {
        if (!soundEnabled) return; // 如果声音被禁用则直接返回
        
        try {
            // 完成音效 - 上升琶音 (C5→E5→G5→C6)
            const audioContext = new (window.AudioContext || window.webkitAudioContext)();
            const notes = [523.25, 659.25, 783.99, 1046.50]; // C5, E5, G5, C6
            
            notes.forEach((frequency, index) => {
                setTimeout(() => {
                    const oscillator = audioContext.createOscillator();
                    const gainNode = audioContext.createGain();
                    
                    oscillator.connect(gainNode);
                    gainNode.connect(audioContext.destination);
                    
                    oscillator.frequency.setValueAtTime(frequency, audioContext.currentTime);
                    oscillator.type = 'sine';
                    
                    // 最大音量设置
                    gainNode.gain.setValueAtTime(0, audioContext.currentTime);
                    gainNode.gain.linearRampToValueAtTime(1.0, audioContext.currentTime + 0.01);
                    gainNode.gain.exponentialRampToValueAtTime(0.01, audioContext.currentTime + 0.3);
                    
                    oscillator.start(audioContext.currentTime);
                    oscillator.stop(audioContext.currentTime + 0.3);
                }, index * 100);
            });
        } catch (error) {
            console.log('无法播放提示音:', error);
        }
    }

    // --- Sound Toggle Logic ---
    function updateSoundButtonState() {
        if (soundEnabled) {
            soundToggleBtn.classList.remove('disabled');
            soundToggleBtn.innerHTML = feather.icons['volume-2'].toSvg();
            soundToggleBtn.title = "提示音已开启，点击关闭";
        } else {
            soundToggleBtn.classList.add('disabled');
            soundToggleBtn.innerHTML = feather.icons['volume-x'].toSvg();
            soundToggleBtn.title = "提示音已关闭，点击开启";
        }
    }

    function toggleSound() {
        soundEnabled = !soundEnabled;
        localStorage.setItem(SOUND_SETTINGS_KEY, JSON.stringify(soundEnabled));
        updateSoundButtonState();
        
        // 如果开启了声音，播放一次提示音作为反馈
        if (soundEnabled) {
            playNotificationSound();
        }
    }

    function loadSoundSettings() {
        const savedSoundSettings = localStorage.getItem(SOUND_SETTINGS_KEY);
        if (savedSoundSettings !== null) {
            soundEnabled = JSON.parse(savedSoundSettings);
        }
        updateSoundButtonState();
    }

    soundToggleBtn.addEventListener('click', toggleSound);
 
    // --- Functions ---

    // --- Saved Prompts Logic ---
    function updateSaveButtonState() {
        const currentPrompt = promptInput.value.trim();
        const prompts = getSavedPrompts();
        if (currentPrompt && prompts.includes(currentPrompt)) {
            savePromptBtn.innerHTML = feather.icons['check-circle'].toSvg();
            savePromptBtn.title = "提示词已保存";
            savePromptBtn.disabled = true;
        } else {
            savePromptBtn.innerHTML = feather.icons['plus-circle'].toSvg();
            savePromptBtn.title = "保存当前提示词";
            savePromptBtn.disabled = false;
        }
    }

    function getSavedPrompts() {
        return JSON.parse(localStorage.getItem(SAVED_PROMPTS_KEY)) || [];
    }

    function savePrompts(prompts) {
        localStorage.setItem(SAVED_PROMPTS_KEY, JSON.stringify(prompts));
    }

    function renderSavedPrompts() {
        const prompts = getSavedPrompts();
        savedPromptsList.innerHTML = ''; // Clear the list first

        if (prompts.length === 0) {
            savedPromptsList.innerHTML = `<div class="saved-prompts-list-empty">没有已保存的提示词</div>`;
            return;
        }

        prompts.forEach((promptText, index) => {
            const item = document.createElement('div');
            item.className = 'saved-prompt-item';
            item.dataset.index = index;

            const text = document.createElement('span');
            text.className = 'saved-prompt-text';
            text.textContent = promptText;
            text.title = promptText; // Show full prompt on hover
            text.addEventListener('click', () => {
                promptInput.value = promptText;
                saveSettings(); // Also save to main settings
                savedPromptsList.classList.add('hidden');
                updateSaveButtonState();
            });

            const deleteBtn = document.createElement('button');
            deleteBtn.className = 'delete-prompt-btn';
            deleteBtn.innerHTML = feather.icons['trash-2'].toSvg({ width: 14, height: 14 });
            deleteBtn.title = '删除此提示词';
            deleteBtn.addEventListener('click', (e) => {
                e.stopPropagation(); // Prevent item click event
                deletePrompt(index);
            });

            item.appendChild(text);
            item.appendChild(deleteBtn);
            savedPromptsList.appendChild(item);
        });
    }

    function addNewPrompt() {
        const currentPrompt = promptInput.value.trim();
        if (!currentPrompt) {
            // Silently return if prompt is empty
            return;
        }

        let prompts = getSavedPrompts();
        if (prompts.includes(currentPrompt)) {
            // Silently return if prompt already exists
            return;
        }

        prompts.unshift(currentPrompt); // Add to the beginning
        savePrompts(prompts);
        renderSavedPrompts();
        updateSaveButtonState();
    }

    function deletePrompt(indexToDelete) {
        let prompts = getSavedPrompts();
        prompts.splice(indexToDelete, 1);
        savePrompts(prompts);
        renderSavedPrompts();
        updateSaveButtonState();
    }

    savePromptBtn.addEventListener('click', addNewPrompt);

    savedPromptsToggle.addEventListener('click', () => {
        const isHidden = savedPromptsList.classList.toggle('hidden');
        if (!isHidden) {
            renderSavedPrompts(); // Re-render when opening
        }
    });

    // Hide dropdown if clicked outside
    document.addEventListener('click', (event) => {
        if (!savedPromptsToggle.contains(event.target) && !savedPromptsList.contains(event.target)) {
            savedPromptsList.classList.add('hidden');
        }
    });

   // --- Saved Keys Logic ---
   function getSavedKeys() {
       return JSON.parse(localStorage.getItem(SAVED_KEYS_KEY)) || [];
   }

   function saveKeys(keys) {
       localStorage.setItem(SAVED_KEYS_KEY, JSON.stringify(keys));
   }

   function getAllKeys() {
       const customKeys = getSavedKeys();
       // Add a 'preset' flag to distinguish them
       const presetKeys = PRESET_KEYS.map(k => ({ ...k, preset: true }));
       return [...presetKeys, ...customKeys];
   }

   function renderSavedKeys() {
       const keys = getAllKeys();
       savedKeysList.innerHTML = ''; // Clear the list

       if (keys.length === 0) {
           savedKeysList.innerHTML = `<div class="saved-keys-list-empty">没有已保存的 Key</div>`;
           return;
       }

       keys.forEach((keyData, index) => {
           const item = document.createElement('div');
           item.className = 'saved-key-item';
           if (keyData.preset) {
               item.classList.add('preset');
           }

           const alias = document.createElement('span');
           alias.className = 'saved-key-alias';
           alias.textContent = keyData.alias;
           alias.title = keyData.alias;

           const value = document.createElement('span');
           value.className = 'saved-key-value';
           // Show partial key for preview
           value.textContent = `...${keyData.value.slice(-6)}`;
           value.title = keyData.value;
           
           const textContainer = document.createElement('div');
           textContainer.style.display = 'flex';
           textContainer.style.alignItems = 'center';
           textContainer.style.overflow = 'hidden';
           textContainer.style.flexGrow = '1';
           textContainer.appendChild(alias);
           textContainer.appendChild(value);

           item.addEventListener('click', () => {
               apiKeyInput.value = keyData.value;
               saveSettings();
               savedKeysList.classList.add('hidden');
               updateSaveKeyButtonState();
           });

           const deleteBtn = document.createElement('button');
           deleteBtn.className = 'delete-key-btn';
           deleteBtn.innerHTML = feather.icons['trash-2'].toSvg({ width: 14, height: 14 });
           deleteBtn.title = '删除此 Key';
           deleteBtn.addEventListener('click', (e) => {
               e.stopPropagation();
               // We need to find the index in the *custom* keys array
               const customKeys = getSavedKeys();
               const customIndexToDelete = customKeys.findIndex(k => k.value === keyData.value);
               if (customIndexToDelete > -1) {
                   deleteKey(customIndexToDelete);
               }
           });

           item.appendChild(textContainer);
           item.appendChild(deleteBtn);
           savedKeysList.appendChild(item);
       });
   }

   function addNewKey() {
       const currentKey = apiKeyInput.value.trim();
       if (!currentKey) return;

       const allKeys = getAllKeys();
       if (allKeys.some(k => k.value === currentKey)) {
           return; // Key already exists
       }

       const alias = prompt("为这个新的 Key 输入一个别名:", "");
       if (alias === null || alias.trim() === "") {
           return; // User cancelled or entered empty alias
       }

       let customKeys = getSavedKeys();
       customKeys.unshift({ alias: alias.trim(), value: currentKey });
       saveKeys(customKeys);
       renderSavedKeys();
       updateSaveKeyButtonState();
   }

   function deleteKey(indexToDelete) {
       let customKeys = getSavedKeys();
       customKeys.splice(indexToDelete, 1);
       saveKeys(customKeys);
       renderSavedKeys();
       updateSaveKeyButtonState();
   }
   
   function updateSaveKeyButtonState() {
       const currentKey = apiKeyInput.value.trim();
       const allKeys = getAllKeys();
       if (currentKey && allKeys.some(k => k.value === currentKey)) {
           saveKeyBtn.innerHTML = feather.icons['check-circle'].toSvg();
           saveKeyBtn.title = "Key 已保存";
           saveKeyBtn.disabled = true;
       } else {
           saveKeyBtn.innerHTML = feather.icons['plus-circle'].toSvg();
           saveKeyBtn.title = "保存当前 Key";
           saveKeyBtn.disabled = false;
       }
   }

   saveKeyBtn.addEventListener('click', addNewKey);

   savedKeysToggle.addEventListener('click', () => {
       const isHidden = savedKeysList.classList.toggle('hidden');
       if (!isHidden) {
           renderSavedKeys();
       }
   });

   document.addEventListener('click', (event) => {
       if (!savedKeysToggle.contains(event.target) && !savedKeysList.contains(event.target)) {
           savedKeysList.classList.add('hidden');
       }
   });

    // --- Settings Persistence ---
    function saveSettings() {
        const settings = {
            apiKey: apiKeyInput.value,
            prompt: promptInput.value,
            negativePrompt: negativePromptInput.value,
            model: modelSelect.value,
            aspectRatio: aspectRatioSelect.value,
            resolution: resolutionSelect.value,
            personGeneration: personGenSelect.value,
            seed: seedInput.value,
            sampleCount: sampleCountInput.value,
            duration: durationInput.value,
            generateAudio: generateAudioSwitch.checked,
            enhancePrompt: enhancePromptSwitch.checked,
            threadCount: threadCountInput.value,
            imageProcessMode: imageProcessModeSelect.value,
            imageFillColor: imageFillColorInput.value,
        };
        localStorage.setItem(SETTINGS_KEY, JSON.stringify(settings));
    }

    function loadSettings() {
        const savedSettings = localStorage.getItem(SETTINGS_KEY);
        if (savedSettings) {
            const settings = JSON.parse(savedSettings);
            apiKeyInput.value = settings.apiKey || '';
            promptInput.value = settings.prompt || '';
            negativePromptInput.value = settings.negativePrompt || '';
            modelSelect.value = settings.model || 'veo-3.0-generate-preview';
            aspectRatioSelect.value = settings.aspectRatio || '16:9';
            resolutionSelect.value = settings.resolution || '1080p';
            personGenSelect.value = settings.personGeneration || 'allow_all';
            seedInput.value = settings.seed || '';
            sampleCountInput.value = settings.sampleCount || '1';
            durationInput.value = settings.duration || '8';
            generateAudioSwitch.checked = settings.generateAudio !== false; // default to true if undefined
            enhancePromptSwitch.checked = settings.enhancePrompt !== false; // default to true if undefined
            threadCountInput.value = settings.threadCount || '1';
            imageProcessModeSelect.value = settings.imageProcessMode || 'none';
            imageFillColorInput.value = settings.imageFillColor || '#000000';
            imageFillColorPicker.value = settings.imageFillColor || '#000000';
            // Update UI state based on loaded settings
            updateImageProcessingState();
            updateSaveButtonState();
        } else {
           // If no settings, load the default preset key
           if (PRESET_KEYS.length > 0) {
               apiKeyInput.value = PRESET_KEYS[0].value;
               saveSettings(); // Save this default state
           }
        }
       updateSaveKeyButtonState(); // Also update key button state on load
    }

    // Attach listeners to save settings on change
    const inputsToSave = [
        apiKeyInput, promptInput, negativePromptInput, modelSelect, aspectRatioSelect,
        resolutionSelect, personGenSelect, seedInput, sampleCountInput, durationInput,
        generateAudioSwitch, threadCountInput, enhancePromptSwitch,
        imageProcessModeSelect, imageFillColorInput
    ];
    inputsToSave.forEach(input => {
        input.addEventListener('change', saveSettings);
        // For text inputs, 'input' event is more responsive
        if (input.type === 'textarea' || input.type === 'text' || input.type === 'password' || input.type === 'number') {
            input.addEventListener('input', saveSettings);
        }
    });

    promptInput.addEventListener('input', updateSaveButtonState);
    apiKeyInput.addEventListener('input', updateSaveKeyButtonState);

   // File Drop Zone Logic V2: With Preview and Delete
   function setupFileDropZone(zoneId, inputId, previewId) {
       const dropZone = document.getElementById(zoneId);
       const fileInput = document.getElementById(inputId);
       const previewContainer = document.getElementById(previewId);
       let currentObjectURL = null;

       const handleFile = (file) => {
           if (currentObjectURL) {
               URL.revokeObjectURL(currentObjectURL);
           }

           if (!file) {
               previewContainer.innerHTML = '';
               dropZone.classList.remove('has-file');
               fileInput.value = ''; // Ensure file is cleared
               return;
           }

           currentObjectURL = URL.createObjectURL(file);
           previewContainer.innerHTML = ''; // Clear previous preview

           let previewElement;
           if (file.type.startsWith('image/')) {
               previewElement = document.createElement('img');
               previewElement.src = currentObjectURL;
           } else if (file.type.startsWith('video/')) {
               previewElement = document.createElement('video');
               previewElement.src = currentObjectURL;
               previewElement.muted = true;
               previewElement.playsInline = true;
               previewElement.setAttribute('preload', 'metadata'); // For poster frame
           }
           
           if(previewElement) {
               previewContainer.appendChild(previewElement);
           }

           const deleteBtn = document.createElement('button');
           deleteBtn.className = 'delete-file-btn';
           deleteBtn.innerHTML = feather.icons['x'].toSvg({ width: 16, height: 16 });
           deleteBtn.setAttribute('aria-label', 'Remove file');
           
           deleteBtn.addEventListener('click', (e) => {
               e.stopPropagation(); // VERY IMPORTANT: Prevents the click from bubbling up to the dropZone
               e.preventDefault();
               handleFile(null); // Clear the file
           });

           previewContainer.appendChild(deleteBtn);
           dropZone.classList.add('has-file');
       };

       dropZone.addEventListener("click", (e) => {
           // If the click is on the delete button, do nothing.
           if (e.target.closest('.delete-file-btn')) {
               return;
           }
           // If the click is on the file input itself, let the browser handle it.
           if (e.target === fileInput) {
               return;
           }
           // Otherwise, for any other part of the zone, trigger the file input.
           fileInput.click();
       });

       dropZone.addEventListener("dragover", (e) => {
           e.preventDefault();
           dropZone.classList.add("dragover");
       });

       dropZone.addEventListener("dragleave", () => {
           dropZone.classList.remove("dragover");
       });

       dropZone.addEventListener("drop", (e) => {
           e.preventDefault();
           dropZone.classList.remove("dragover");
           if (e.dataTransfer.files.length) {
               fileInput.files = e.dataTransfer.files;
               handleFile(fileInput.files[0]);
           }
       });

       fileInput.addEventListener("change", () => {
            if (fileInput.files.length > 0) {
               handleFile(fileInput.files[0]);
           } else {
               handleFile(null);
           }
       });
   }

   setupFileDropZone("image-drop-zone", "image-prompt", "image-preview");
   setupFileDropZone("video-drop-zone", "video-prompt", "video-preview");

   // --- Image Processing UI Logic ---
   function updateImageProcessingState() {
       const isFillMode = imageProcessModeSelect.value === 'fill';
       const processGroup = imageProcessModeSelect.closest('.form-group');

       // 移除了基于宽高比的禁用限制，现在所有宽高比都可以使用图片处理功能
       processGroup.classList.remove('disabled');
       imageProcessModeSelect.disabled = false;

       // Color picker is enabled only in fill mode
       if (isFillMode) {
           imageFillColorGroup.classList.remove('disabled');
           imageFillColorPicker.disabled = false;
           imageFillColorInput.disabled = false;
       } else {
           imageFillColorGroup.classList.add('disabled');
           imageFillColorPicker.disabled = true;
           imageFillColorInput.disabled = true;
       }
   }

   aspectRatioSelect.addEventListener('change', updateImageProcessingState);
   imageProcessModeSelect.addEventListener('change', updateImageProcessingState);

   imageFillColorPicker.addEventListener('input', () => {
       imageFillColorInput.value = imageFillColorPicker.value;
       saveSettings(); // Save on color change
   });

   imageFillColorInput.addEventListener('input', () => {
       const value = imageFillColorInput.value;
       // A simple regex to check for valid hex color format
       if (/^#[0-9a-fA-F]{6}$/.test(value)) {
           imageFillColorPicker.value = value;
           saveSettings(); // Save on text input change
       }
   });

   // Carousel Logic
   function updateCarousel() {
        videoCarousel.style.transform = `translateX(-${currentIndex * 100}%)`;
        updateSaveVideoButtonState(); // Update save button state when carousel changes
        
        const dots = carouselDots.querySelectorAll('.carousel-dot');
        dots.forEach((dot, index) => {
            dot.classList.toggle('active', index === currentIndex);
        });

        const videos = videoCarousel.querySelectorAll('video');
        videos.forEach((video, index) => {
            if (index !== currentIndex) {
                video.pause();
            }
        });
    }

    function resetCarousel() {
        videoCarousel.innerHTML = '';
        carouselDots.innerHTML = '';
        videoItems = [];
        currentIndex = 0;
        prevBtn.classList.add('hidden');
        nextBtn.classList.add('hidden');
        placeholder.style.display = 'flex';
        saveVideoBtn.disabled = true; // Disable button when there are no videos
        savedVideos = []; // Reset saved videos tracker
    }

    prevBtn.addEventListener('click', () => {
        currentIndex = (currentIndex > 0) ? currentIndex - 1 : videoItems.length - 1;
        updateCarousel();
    });

    nextBtn.addEventListener('click', () => {
        currentIndex = (currentIndex < videoItems.length - 1) ? currentIndex + 1 : 0;
        updateCarousel();
    });

    // --- Video Handling ---
    function addVideoToCarousel(videoUrl) {
        const index = videoItems.length;
        videoItems.push(videoUrl);

        const item = document.createElement('div');
        item.className = 'carousel-item';
        const video = document.createElement('video');
        video.src = videoUrl;
        video.controls = true;
        video.addEventListener('click', (e) => {
            e.preventDefault();
            if (video.paused) {
                video.play();
            } else {
                video.pause();
            }
        });
        item.appendChild(video);
        videoCarousel.appendChild(item);

        const dot = document.createElement('div');
        dot.className = 'carousel-dot';
        dot.addEventListener('click', () => {
            currentIndex = index;
            updateCarousel();
        });
        carouselDots.appendChild(dot);

        if (videoItems.length > 1) {
            prevBtn.classList.remove('hidden');
            nextBtn.classList.remove('hidden');
        }
        
        // If it's the first video, hide loader and update display
        if (videoItems.length === 1) {
            loader.classList.add("hidden");
            placeholder.style.display = "none";
            updateCarousel();
            saveVideoBtn.disabled = false; // Enable the save button
        }
    }


    // --- Form Submission ---
    generateBtn.addEventListener("click", async () => {
        resetCarousel();
        loader.classList.remove("hidden");
        placeholder.style.display = "none";
        errorContainer.classList.add("hidden");

        const threadCount = parseInt(threadCountInput.value, 10) || 1;
        const sampleCount = parseInt(sampleCountInput.value, 10) || 1;

        const baseFormData = () => {
            const formData = new FormData();
            formData.append("api_key", apiKeyInput.value);
            formData.append("prompt", promptInput.value);
            formData.append("negative_prompt", negativePromptInput.value);
            formData.append("model", modelSelect.value);
            formData.append("aspect_ratio", aspectRatioSelect.value);
            formData.append("duration", durationInput.value);
            formData.append("resolution", resolutionSelect.value);
            if (seedInput.value) {
                formData.append("seed", seedInput.value);
            }
            formData.append("person_generation", personGenSelect.value);
            formData.append("generate_audio", generateAudioSwitch.checked);
            formData.append("enhance_prompt", enhancePromptSwitch.checked);

            if (imagePromptInput.files[0]) {
                formData.append("image", imagePromptInput.files[0]);
            }
            if (videoPromptInput.files[0]) {
                formData.append("video", videoPromptInput.files[0]);
            }
            
            // 现在所有宽高比都支持图片处理参数
            formData.append("image_process_mode", imageProcessModeSelect.value);
            formData.append("image_fill_color", imageFillColorInput.value);

            return formData;
        };

        if (threadCount > 1) {
            const requests = [];
            for (let i = 0; i < threadCount; i++) {
                const formData = baseFormData();
                formData.append("sample_count", String(sampleCount)); // 每个线程生成 sampleCount 个视频

                const request = fetch("/api/generate_video", {
                    method: "POST",
                    body: formData,
                })
                .then(response => {
                    if (!response.ok) {
                        return response.json().then(err => Promise.reject(err));
                    }
                    return response.json();
                })
                .then(data => {
                    if (data.video_urls && data.video_urls.length > 0) {
                        // 将该线程返回的全部视频加入轮播
                        data.video_urls.forEach(addVideoToCarousel);
                    }
                })
                .catch(error => {
                    console.error(`Thread ${i + 1} failed:`, error.detail || error.message);
                });
                requests.push(request);
            }

            Promise.allSettled(requests).then(() => {
                if (videoItems.length === 0) {
                    // All requests failed
                    errorContainer.textContent = "所有视频生成请求均失败。";
                    errorContainer.classList.remove("hidden");
                    resetCarousel();
                } else {
                    // At least one video was generated successfully
                    playNotificationSound();
                }
                loader.classList.add("hidden");
            });

        } else {
            // --- Single Request Logic (Original Flow) ---
            const formData = baseFormData();
            formData.append("sample_count", sampleCountInput.value);

            try {
                const response = await fetch("/api/generate_video", {
                    method: "POST",
                    body: formData,
                });

                const data = await response.json();
                if (!response.ok) {
                    throw new Error(data.detail || "发生未知错误。");
                }
                
                const urls = data.video_urls;
                if (!urls || !Array.isArray(urls) || urls.length === 0) {
                    throw new Error("API响应格式不正确或未返回视频。");
                }

                urls.forEach(addVideoToCarousel);
                
                if (videoItems.length > 0) {
                    currentIndex = 0;
                    updateCarousel();
                    playNotificationSound(); // Play notification sound for successful generation
                } else {
                    resetCarousel(); // No videos were successfully added
                }

            } catch (error) {
                errorContainer.textContent = error.message;
                errorContainer.classList.remove("hidden");
                resetCarousel();
            } finally {
                loader.classList.add("hidden");
            }
        }
    });

    // --- Save Video Logic ---
    function updateSaveVideoButtonState() {
        if (videoItems.length === 0) {
            saveVideoBtn.disabled = true;
            saveVideoBtn.classList.remove('saved');
            saveVideoBtn.querySelector('span').textContent = '保存此视频到服务器';
            return;
        }

        const currentVideoUrl = videoItems[currentIndex];
        if (savedVideos.includes(currentVideoUrl)) {
            saveVideoBtn.disabled = true;
            saveVideoBtn.classList.add('saved');
            saveVideoBtn.querySelector('span').textContent = '已保存至服务器';
        } else {
            saveVideoBtn.disabled = false;
            saveVideoBtn.classList.remove('saved');
            saveVideoBtn.querySelector('span').textContent = '保存此视频到服务器';
        }
    }

    async function saveCurrentVideo() {
        if (videoItems.length === 0) return;

        const videoUrlToSave = videoItems[currentIndex];
        if (savedVideos.includes(videoUrlToSave)) return;

        // Temporarily disable to prevent double-clicking
        saveVideoBtn.disabled = true;
        const originalText = saveVideoBtn.querySelector('span').textContent;
        saveVideoBtn.querySelector('span').textContent = '保存中...';

        try {
            const formData = new FormData();
            formData.append('video_url', videoUrlToSave);

            const response = await fetch('/api/save_video', {
                method: 'POST',
                body: formData,
            });

            const data = await response.json();

            if (!response.ok) {
                throw new Error(data.detail || '保存失败');
            }

            // Success
            savedVideos.push(videoUrlToSave);
            updateSaveVideoButtonState();

        } catch (error) {
            // Show a temporary error message on the button
            saveVideoBtn.querySelector('span').textContent = '保存失败!';
            console.error('Save video error:', error);
            // Revert button state after a delay
            setTimeout(() => {
                saveVideoBtn.querySelector('span').textContent = originalText;
                updateSaveVideoButtonState(); // Re-evaluates the correct state
            }, 2000);
        }
    }

    saveVideoBtn.addEventListener('click', saveCurrentVideo);



    // --- Paste to Upload Logic ---
    const imageDropZone = document.getElementById("image-drop-zone");
    const videoDropZone = document.getElementById("video-drop-zone");

    imageDropZone.addEventListener('mouseenter', () => currentPasteTarget = 'image');
    imageDropZone.addEventListener('mouseleave', () => currentPasteTarget = null);

    videoDropZone.addEventListener('mouseenter', () => currentPasteTarget = 'video');
    videoDropZone.addEventListener('mouseleave', () => currentPasteTarget = null);

    document.addEventListener('paste', (event) => {
        if (!currentPasteTarget) return;

        // Don't interfere with text inputs
        const activeElement = document.activeElement;
        if (activeElement && (activeElement.tagName === 'INPUT' || activeElement.tagName === 'TEXTAREA')) {
            return;
        }

        const items = event.clipboardData.items;
        if (!items) return;

        for (let i = 0; i < items.length; i++) {
            if (items[i].kind === 'file') {
                const file = items[i].getAsFile();
                if (!file) continue;

                event.preventDefault(); // Prevent default paste behavior

                if (currentPasteTarget === 'image' && file.type.startsWith('image/')) {
                    // Create a new FileList and assign it to the input
                    const dataTransfer = new DataTransfer();
                    dataTransfer.items.add(file);
                    imagePromptInput.files = dataTransfer.files;
                    // Manually trigger the change event to update the UI
                    imagePromptInput.dispatchEvent(new Event('change'));
                    break; // Handle only the first valid file
                }

                if (currentPasteTarget === 'video' && file.type.startsWith('video/')) {
                    const dataTransfer = new DataTransfer();
                    dataTransfer.items.add(file);
                    videoPromptInput.files = dataTransfer.files;
                    videoPromptInput.dispatchEvent(new Event('change'));
                    break; // Handle only the first valid file
                }
            }
        }
    });

    // --- Initial Load ---
    loadSettings();
    loadSoundSettings(); // Load sound settings
    // Set initial state for image processing UI
    updateImageProcessingState();
    updateSaveButtonState();
    renderSavedKeys(); // Initial render of the key list
});