// State
let currentEventSource = null;
let currentTab = 'observation'; // Track which tab we're writing to
let currentSection = 'reasoning'; // 'reasoning' | 'conclusion', 由 SSE section 事件驱动

// DOM elements
const scopeSelect = document.getElementById('scopeSelect');
const questionInput = document.getElementById('questionInput');
const startBtn = document.getElementById('startBtn');
const presetBtns = document.querySelectorAll('.preset-btn');

const observationContent = document.getElementById('observationContent');
const promptContent = document.getElementById('promptContent');
const reasoningContent = document.getElementById('reasoningContent');
const conclusionContent = document.getElementById('conclusionContent');

// Programmatic tab switching (Bootstrap tabs)
function switchTab(name) {
    const btn = document.getElementById(name + '-tab');
    if (btn) btn.click();
}

// Tab switching
document.querySelectorAll('#outputTabs button').forEach(button => {
    button.addEventListener('click', (e) => {
        const tabId = e.target.id.replace('-tab', '');
        currentTab = tabId;
    });
});

// Preset button click
presetBtns.forEach(btn => {
    btn.addEventListener('click', () => {
        const preset = btn.dataset.preset;
        startAnalysis(null, preset);
    });
});

// Start button click
startBtn.addEventListener('click', () => {
    const question = questionInput.value.trim();
    if (!question) {
        alert('请输入自定义问题或选择预设分析');
        return;
    }
    startAnalysis(question, null);
});

function startAnalysis(question, preset) {
    // Close existing connection
    if (currentEventSource) {
        currentEventSource.close();
        currentEventSource = null;
    }
    
    // Reset content
    observationContent.innerHTML = '<div class="text-muted">正在收集上下文...</div>';
    promptContent.innerHTML = '<div class="text-muted">等待...</div>';
    reasoningContent.innerHTML = '<div class="text-muted">等待...</div>';
    conclusionContent.innerHTML = '<div class="text-muted">等待...</div>';
    currentSection = 'reasoning';
    
    // Build URL
    const scope = scopeSelect.value;
    const params = new URLSearchParams({scope});
    if (question) params.append('question', question);
    if (preset) params.append('preset', preset);
    
    const url = `/api/analyze/stream?${params.toString()}`;
    
    // Start SSE
    currentEventSource = new EventSource(url);
    
    // Handle step events
    currentEventSource.addEventListener('step', (e) => {
        const data = JSON.parse(e.data);
        const step = data.step;
        const content = data.content;
        
        if (step === 'context') {
            observationContent.innerHTML = `<div class="alert alert-info">${escapeHtml(content)}</div>`;
        } else if (step === 'prompt') {
            promptContent.innerHTML = `<pre class="bg-light p-3 rounded" style="white-space: pre-wrap;">${escapeHtml(content)}</pre>`;
        } else if (step === 'complete') {
            // 追加提示, 不覆盖已流式写入的结论内容
            conclusionContent.innerHTML += `<div class="alert alert-success">${escapeHtml(content)}</div>`;
            currentEventSource.close();
            currentEventSource = null;
        }
    });

    // Section 事件: 后端识别 ===REASONING=== / ===CONCLUSION=== 后显式下发
    currentEventSource.addEventListener('reasoning_start', () => {
        currentSection = 'reasoning';
        reasoningContent.innerHTML = '';
        switchTab('reasoning');
    });

    currentEventSource.addEventListener('conclusion_start', () => {
        currentSection = 'conclusion';
        conclusionContent.innerHTML = '';
        switchTab('conclusion');
    });

    // Handle token events (streaming LLM output, 分隔符已被后端剥离)
    currentEventSource.addEventListener('token', (e) => {
        const data = JSON.parse(e.data);
        const text = data.text;
        const pane = currentSection === 'conclusion' ? conclusionContent : reasoningContent;
        if (pane.querySelector('.text-muted')) pane.innerHTML = '';
        pane.innerHTML += escapeHtml(text);
        pane.scrollTop = pane.scrollHeight;
    });
    
    // Handle errors
    currentEventSource.addEventListener('error', (e) => {
        const data = JSON.parse(e.data);
        const errorMsg = data.error || '未知错误';
        observationContent.innerHTML = `<div class="alert alert-danger">错误: ${escapeHtml(errorMsg)}</div>`;
        currentEventSource.close();
        currentEventSource = null;
    });
    
    currentEventSource.onerror = (e) => {
        observationContent.innerHTML = `<div class="alert alert-danger">连接错误, 请检查后端日志</div>`;
        currentEventSource.close();
        currentEventSource = null;
    };
}

// Helper: escape HTML
function escapeHtml(text) {
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
}