document.addEventListener('DOMContentLoaded', () => {
    const numberInput = document.getElementById('numberInput');
    const fileInput = document.getElementById('fileInput');
    const dropzone = document.getElementById('dropzone');
    const splitMode = document.getElementById('splitMode');
    const splitValue = document.getElementById('splitValue');
    const splitBtn = document.getElementById('splitBtn');
    const autoDedupe = document.getElementById('autoDedupe');
    const resultsContainer = document.getElementById('resultsContainer');
    const totalCountEl = document.getElementById('totalCount');
    const uniqueCountEl = document.getElementById('uniqueCount');
    const dynamicCountsContainer = document.getElementById('dynamicCountsContainer');
    const dynamicInputsList = document.getElementById('dynamicInputsList');
    const unitText = document.getElementById('unitText');
    const batchCountBadge = document.getElementById('batchCountBadge');
    
    let allNumbers = [];

    // Helper: Extract numbers from text (Flexible digit extraction)
    const extractNumbers = (text) => {
        // First try to match standard 11-digit mobile numbers
        let matches = text.match(/1[3-9]\d{9}/g) || [];
        
        // If no mobile numbers found, try matching any sequence of 5-15 digits (IDs, account numbers, etc.)
        if (matches.length === 0) {
            matches = text.match(/\d{5,15}/g) || [];
        }
        return matches;
    };

    // Update stats and allNumbers array
    const updateStats = () => {
        const text = numberInput.value;
        const extracted = extractNumbers(text);
        const unique = [...new Set(extracted)];
        
        totalCountEl.textContent = extracted.length.toLocaleString();
        uniqueCountEl.textContent = unique.length.toLocaleString();
        
        allNumbers = autoDedupe.checked ? unique : extracted;
    };

    numberInput.addEventListener('input', updateStats);
    autoDedupe.addEventListener('change', updateStats);

    // Dynamic UI for split modes
    const updateSplitUI = () => {
        const mode = splitMode.value;
        if (mode === 'count') {
            unitText.textContent = '份';
            generateDynamicInputs();
        } else {
            unitText.textContent = '条';
            dynamicCountsContainer.classList.add('d-none');
        }
    };

    const generateDynamicInputs = () => {
        const numBatches = parseInt(splitValue.value);
        dynamicInputsList.innerHTML = '';
        
        if (isNaN(numBatches) || numBatches <= 1 || splitMode.value !== 'count') {
            dynamicCountsContainer.classList.add('d-none');
            return;
        }

        dynamicCountsContainer.classList.remove('d-none');
        
        // Create N-1 inputs because the last one is always the remainder
        for (let i = 0; i < numBatches - 1; i++) {
            const div = document.createElement('div');
            div.className = 'input-group input-group-sm mb-2';
            div.innerHTML = `
                <span class="input-group-text bg-white border-2 fw-bold" style="width: 100px;">第 ${i + 1} 份数量</span>
                <input type="number" class="form-control border-2 batch-size-input" placeholder="留空则自动分配" min="1">
            `;
            dynamicInputsList.appendChild(div);
        }
    };

    splitMode.addEventListener('change', updateSplitUI);
    splitValue.addEventListener('input', generateDynamicInputs);

    // File handling
    const handleFile = (file) => {
        if (!file) return;
        const reader = new FileReader();
        reader.onload = (event) => {
            const content = event.target.result;
            numberInput.value += (numberInput.value ? '\n' : '') + content;
            updateStats();
            fileInput.value = '';
        };
        reader.readAsText(file);
    };

    dropzone.addEventListener('click', () => fileInput.click());
    fileInput.addEventListener('change', (e) => handleFile(e.target.files[0]));

    // Drag and Drop
    ['dragenter', 'dragover', 'dragleave', 'drop'].forEach(eventName => {
        dropzone.addEventListener(eventName, (e) => {
            e.preventDefault();
            e.stopPropagation();
        }, false);
    });

    ['dragenter', 'dragover'].forEach(eventName => {
        dropzone.addEventListener(eventName, () => dropzone.classList.add('drag-active'), false);
    });

    ['dragleave', 'drop'].forEach(eventName => {
        dropzone.addEventListener(eventName, () => dropzone.classList.remove('drag-active'), false);
    });

    dropzone.addEventListener('drop', (e) => {
        const dt = e.dataTransfer;
        const file = dt.files[0];
        handleFile(file);
    }, false);

    // Splitting logic
    splitBtn.addEventListener('click', () => {
        updateStats(); 
        if (allNumbers.length === 0) {
            alert('请先导入或粘贴号码！');
            return;
        }

        const mode = splitMode.value;
        const val = parseInt(splitValue.value);

        if (isNaN(val) || val <= 0) {
            alert('请输入有效的分批数值！');
            return;
        }

        let batches = [];
        let tempNumbers = [...allNumbers];

        if (mode === 'count') {
            const sizeInputs = document.querySelectorAll('.batch-size-input');
            let hasAnySpecificSize = false;
            let specificSizes = [];
            
            sizeInputs.forEach(input => {
                const s = parseInt(input.value);
                if (!isNaN(s) && s > 0) {
                    hasAnySpecificSize = true;
                    specificSizes.push(s);
                } else {
                    specificSizes.push(null);
                }
            });

            if (hasAnySpecificSize) {
                // If some sizes are specified, follow them.
                for (let i = 0; i < val - 1; i++) {
                    const size = specificSizes[i];
                    if (size !== null && size > 0) {
                        batches.push(tempNumbers.splice(0, size));
                    } else {
                        // For empty inputs when others are filled, we calculate an average of the remaining
                        const remainingSlots = val - batches.length;
                        const avg = Math.ceil(tempNumbers.length / remainingSlots);
                        batches.push(tempNumbers.splice(0, avg));
                    }
                }
                // Last batch always gets the remainder
                batches.push(tempNumbers);
            } else {
                // Default even split if no inputs are filled
                const batchSize = Math.ceil(tempNumbers.length / val);
                for (let i = 0; i < val; i++) {
                    if (i === val - 1) {
                        batches.push(tempNumbers); // Last one takes all remainder
                    } else {
                        batches.push(tempNumbers.splice(0, batchSize));
                    }
                }
            }
        } else {
            // Split by fixed size per batch (mode === 'size')
            while (tempNumbers.length > 0) {
                batches.push(tempNumbers.splice(0, val));
            }
        }

        renderResults(batches);
    });

    const renderResults = (batches) => {
        resultsContainer.innerHTML = '';
        // Filter out empty batches if they occurred due to split logic
        const finalBatches = batches.filter(b => b.length > 0);
        
        batchCountBadge.textContent = `${finalBatches.length} 个批次`;
        batchCountBadge.classList.remove('d-none');
        
        finalBatches.forEach((batch, index) => {
            const card = document.createElement('div');
            card.className = 'card batch-card animate-fadeIn';
            
            const previewText = batch.slice(0, 15).join(', ');
            const hasMore = batch.length > 15;

            card.innerHTML = `
                <div class="card-body p-4">
                    <div class="batch-header">
                        <div class="batch-title">
                            <span class="badge bg-primary" style="background: var(--primary-gradient) !important;">第 ${index + 1} 份</span>
                            <span class="badge-count">${batch.length.toLocaleString()} 条</span>
                        </div>
                        <button class="btn btn-primary btn-sm px-3 download-btn">
                            <i data-lucide="download" style="width: 14px;"></i> 下载
                        </button>
                    </div>
                    <div class="mb-3">
                        <input type="text" class="form-control form-control-sm bg-light border-0 remark-input" placeholder="备注名称（即文件名）">
                    </div>
                    <div class="small text-muted font-monospace bg-light p-2 rounded" style="font-size: 0.75rem; word-break: break-all;">
                        预览: ${batch.length > 0 ? previewText + (hasMore ? ' ...' : '') : '无号码'}
                    </div>
                </div>
            `;
            
            resultsContainer.appendChild(card);
            
            // Download handler
            card.querySelector('.download-btn').addEventListener('click', () => {
                const remark = card.querySelector('.remark-input').value.trim() || 
`batch_${index + 1}_${batch.length}`;
                const blob = new Blob([batch.join('\n')], { type: 'text/plain;charset=utf-8' });
                const url = URL.createObjectURL(blob);
                const a = document.createElement('a');
                a.href = url;
                a.download = `${remark}.txt`;
                document.body.appendChild(a);
                a.click();
                document.body.removeChild(a);
                URL.revokeObjectURL(url);
            });
        });

        if (window.lucide) {
            lucide.createIcons();
        }
        
        resultsContainer.scrollIntoView({ behavior: 'smooth', block: 'start' });
    };

    // Initial UI Setup
    updateSplitUI();
});