import { sessionId, setSessionId, setCurrentPersona, currentPersona, dom } from './state.js';
import { clearMessages, addMessage, initChat } from './chat.js';
import { highlightPersona } from './personas.js';

function escapeTitle(t) {
    const d = document.createElement('div');
    d.textContent = t;
    return d.innerHTML;
}

export async function loadSessions() {
    const res = await fetch('/sessions/');
    const sessions = await res.json();
    dom.sessionList.innerHTML = '';

    sessions.forEach(s => {
        const item = document.createElement('div');
        item.className = 'session-item' + (s.session_id === sessionId ? ' active' : '');
        item.innerHTML = `
            <div class="s-title">${escapeTitle(s.title || 'Новый чат')}</div>
            <div class="s-meta">${s.message_count} сообщ.</div>
            <button class="s-del" type="button">🗑</button>
        `;
        item.addEventListener('click', () => switchSession(s.session_id));
        item.querySelector('.s-del').addEventListener('click', async (e) => {
            e.stopPropagation();
            await fetch(`/sessions/${s.session_id}`, { method: 'DELETE' });
            if (s.session_id === sessionId) createNewChat();
            else loadSessions();
        });
        dom.sessionList.appendChild(item);
    });
}

export async function switchSession(id) {
    setSessionId(id);
    clearMessages();
    await loadSessions();
    await loadChatHistory(id);
}

export async function loadChatHistory(id) {
    const sessionRes = await fetch(`/sessions/${id}`);
    if (sessionRes.ok) {
        const s = await sessionRes.json();
        dom.headerTitle.textContent = s.title || 'Новый чат';
        if (s.persona_id) {
            setCurrentPersona(s.persona_id);
            highlightPersona(s.persona_id);
        }
    }

    const histRes = await fetch(`/chat/history/${id}`);
    if (!histRes.ok) return;

    const messages = await histRes.json();
    clearMessages();
    messages.filter(m => m.role !== 'system').forEach(m => {
        addMessage(
            m.role === 'user' ? 'user' : 'assistant',
            m.content,
            m.image_prompt,
            m.image_path ? `/static/${m.image_path}` : null,
        );
    });
}

export async function createNewChat() {
    setSessionId('sess_' + Math.random().toString(36).slice(2, 10));
    clearMessages();
    dom.headerTitle.textContent = 'Новый чат';
    highlightPersona(currentPersona);
    await initChat();
    loadSessions();
}

export async function initSessions() {
    await loadSessions();
    if (sessionId) {
        const check = await fetch(`/sessions/${sessionId}`);
        if (check.ok) await switchSession(sessionId);
        else createNewChat();
    } else {
        createNewChat();
    }
}