document.addEventListener('DOMContentLoaded', () => {
    const startBtn = document.getElementById('startBtn');
    const topicInput = document.getElementById('topicInput');
    const arena = document.getElementById('arena');
    const globalStatus = document.getElementById('globalStatus');
    const modelStatusList = document.getElementById('modelStatusList');

    const MODELS = [
        'openai/gpt-oss-120b',
        'llama-3.3-70b-versatile',
        'qwen/qwen3-32b',
        'gemini-2.5-flash',
        'Gemma 4 (Architect)'
    ];

    function initSidebar() {
        modelStatusList.innerHTML = '';
        MODELS.forEach(m => {
            const li = document.createElement('li');
            li.id = `status-${m.replace(/[^a-zA-Z0-9]/g, '')}`;
            li.innerHTML = `
                <span class="model-name">${m}</span>
                <span class="model-status">Awaiting task</span>
            `;
            modelStatusList.appendChild(li);
        });
    }

    initSidebar();

    startBtn.addEventListener('click', async () => {
        const topic = topicInput.value.trim();
        if (!topic) return;

        startBtn.disabled = true;
        arena.innerHTML = '';
        initSidebar();

        try {
            const response = await fetch('/api/debate', {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ topic })
            });

            const reader = response.body.getReader();
            const decoder = new TextDecoder("utf-8");

            let buffer = "";

            while (true) {
                const { done, value } = await reader.read();
                if (done) break;

                buffer += decoder.decode(value, { stream: true });
                const lines = buffer.split('\n\n');
                
                buffer = lines.pop() || "";

                for (const chunk of lines) {
                    if (chunk.trim() === '') continue;
                    
                    const eventMatch = chunk.match(/event: (.*)\n/);
                    const dataMatch = chunk.match(/data: (.*)/);

                    if (eventMatch && dataMatch) {
                        const event = eventMatch[1];
                        const data = JSON.parse(dataMatch[1]);
                        handleEvent(event, data);
                    }
                }
            }
        } catch (error) {
            console.error(error);
            globalStatus.innerText = "Error occurred.";
        } finally {
            startBtn.disabled = false;
        }
    });

    function handleEvent(event, data) {
        if (event === 'status') {
            globalStatus.innerText = data.message;
        } 
        else if (event === 'model_start') {
            const id = `status-${data.model.replace(/[^a-zA-Z0-9]/g, '')}`;
            const el = document.getElementById(id);
            if (el) {
                el.className = 'active';
                el.querySelector('.model-status').innerHTML = `<span class="pulse-text">Thinking (Round ${data.round})...</span>`;
            }
        }
        else if (event === 'model_end') {
            const id = `status-${data.model.replace(/[^a-zA-Z0-9]/g, '')}`;
            const el = document.getElementById(id);
            if (el) {
                el.className = 'done';
                el.querySelector('.model-status').innerText = `Finished Round ${data.round}`;
            }
            appendMessage(data.model, data.round, data.content);
        }
        else if (event === 'done') {
            globalStatus.innerText = "Debate Concluded. Final Verdict Delivered.";
            globalStatus.classList.remove('pulse-text');
            MODELS.forEach(m => {
                const id = `status-${m.replace(/[^a-zA-Z0-9]/g, '')}`;
                const el = document.getElementById(id);
                if (el) { el.classList.remove('active'); el.classList.remove('done'); }
            });
        }
    }

    function appendMessage(model, round, markdownContent) {
        const div = document.createElement('div');
        div.className = `message-bubble ${model.includes('Architect') ? 'architect' : ''}`;
        div.style.animationDelay = `${0.1 * document.querySelectorAll('.message-bubble').length}s`;
        
        let roundLabel = round === 'Final' ? 'VERDICT' : `Round ${round}`;
        
        div.innerHTML = `
            <div class="bubble-header">
                <span>${model}</span>
                <span class="round">${roundLabel}</span>
            </div>
            <div class="bubble-content">
                ${marked.parse(markdownContent)}
            </div>
        `;
        arena.appendChild(div);
        arena.scrollTop = arena.scrollHeight;
    }
});