// ============================================
// Session Management
// ============================================

async function fetchSessions() {
    try {
        const response = await apiFetch('/api/sessions');
        if (response.ok) {
            return await response.json();
        }
    } catch (e) {
        console.error('Failed to fetch sessions:', e);
    }
    return { sessions: [], current: null };
}

function showSessionSelector(sessions) {
    const selector = document.getElementById('sessionSelector');
    const welcome = document.getElementById('welcomeMessage');
    const sessionIndicator = document.getElementById('sessionIndicator');
    const inputArea = document.getElementById('commandInputArea');

    // Show welcome message and session selector, hide sidebar
    if (welcome) welcome.style.display = 'block';
    if (selector) selector.style.display = 'block';
    if (sessionIndicator) sessionIndicator.style.display = 'none';
    if (inputArea) inputArea.style.display = 'none';
    const sidebar = document.getElementById('agentsSidebar');
    if (sidebar) sidebar.style.display = 'none';

    // Populate existing sessions dropdown
    const select = document.getElementById('existingSessionSelect');
    if (select) {
        select.innerHTML = '<option value="">-- Select session --</option>';
        sessions.forEach(session => {
            const option = document.createElement('option');
            option.value = session.name;
            option.textContent = `${session.name} (${formatDate(session.modified)})`;
            select.appendChild(option);
        });
    }
}

function hideSessionSelector() {
    const selector = document.getElementById('sessionSelector');
    const welcome = document.getElementById('welcomeMessage');
    const sessionIndicator = document.getElementById('sessionIndicator');
    const inputArea = document.getElementById('commandInputArea');

    // Hide session selector, show session indicator, input, and sidebar
    if (selector) selector.style.display = 'none';
    if (welcome) welcome.style.display = 'block';
    if (sessionIndicator) sessionIndicator.style.display = 'block';
    if (inputArea) inputArea.style.display = 'block';
    const sidebar = document.getElementById('agentsSidebar');
    if (sidebar) sidebar.style.display = '';
}

async function onSessionSelected(sessionName) {
    currentSession = sessionName;
    hideSessionSelector();

    // Update session name display
    const nameEl = document.getElementById('currentSessionName');
    if (nameEl) nameEl.textContent = sessionName;

    const renameInput = document.getElementById('currentSessionRename');
    if (renameInput) renameInput.value = sessionName;

    // Update timeline title to show session name
    if (timelineData[0]) {
        timelineData[0].title = sessionName;
        renderTimeline();
    }

    // Load workspace for this session
    await loadWorkspace();

    // Refresh sessions panel list
    await refreshSessionsList();
}

async function createSession(name) {
    try {
        const response = await apiFetch('/api/sessions', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ name })
        });
        if (response.ok) {
            const data = await response.json();
            await onSessionSelected(data.name);
            return true;
        } else {
            const error = await response.json();
            alert(error.detail || 'Failed to create session');
        }
    } catch (e) {
        console.error('Failed to create session:', e);
        alert('Failed to create session');
    }
    return false;
}

async function selectSession(name) {
    try {
        const response = await apiFetch('/api/sessions/select', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ name })
        });
        if (response.ok) {
            // Reset local state and load the selected session
            resetLocalState();
            await onSessionSelected(name);
            return true;
        } else {
            const error = await response.json();
            alert(error.detail || 'Failed to select session');
        }
    } catch (e) {
        console.error('Failed to select session:', e);
        alert('Failed to select session');
    }
    return false;
}

async function renameSession(oldName, newName) {
    try {
        const response = await apiFetch('/api/sessions/rename', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ oldName, newName })
        });
        if (response.ok) {
            const data = await response.json();
            currentSession = data.name;

            // Update displays
            const nameEl = document.getElementById('currentSessionName');
            if (nameEl) nameEl.textContent = data.name;

            // Update timeline title
            if (timelineData[0]) {
                timelineData[0].title = data.name;
                renderTimeline();
            }

            await refreshSessionsList();
            return true;
        } else {
            const error = await response.json();
            alert(error.detail || 'Failed to rename session');
        }
    } catch (e) {
        console.error('Failed to rename session:', e);
        alert('Failed to rename session');
    }
    return false;
}

function openSessionsPanel() {
    const sessionsBtn = document.getElementById('sessionsBtn');
    if (sessionsBtn) {
        sessionsBtn.click();
    }
}

async function refreshSessionsList() {
    const sessionsData = await fetchSessions();
    const listEl = document.getElementById('sessionsList');

    // Update the current session rename input
    const renameInput = document.getElementById('currentSessionRename');
    if (renameInput && currentSession) {
        renameInput.value = currentSession;
    }

    if (!listEl) return;

    if (sessionsData.sessions.length === 0) {
        listEl.innerHTML = '<div class="sessions-loading">No other sessions</div>';
        return;
    }

    listEl.innerHTML = '';
    sessionsData.sessions.forEach(session => {
        const item = document.createElement('div');
        item.className = 'sessions-list-item' + (session.name === currentSession ? ' current' : '');

        const isCurrent = session.name === currentSession;
        item.innerHTML = `
            <span class="sessions-list-item-name">${escapeHtml(session.name)}</span>
            <span class="sessions-list-item-date">${formatDate(session.modified)}</span>
            ${!isCurrent ? `<button class="sessions-delete-btn" title="Delete session">×</button>` : ''}
        `;

        if (!isCurrent) {
            // Click on name/date to select
            item.querySelector('.sessions-list-item-name').addEventListener('click', () => selectSession(session.name));
            item.querySelector('.sessions-list-item-date').addEventListener('click', () => selectSession(session.name));

            // Click on delete button to delete
            const deleteBtn = item.querySelector('.sessions-delete-btn');
            if (deleteBtn) {
                deleteBtn.addEventListener('click', (e) => {
                    e.stopPropagation();
                    deleteSession(session.name);
                });
            }
        }

        listEl.appendChild(item);
    });
}

async function deleteSession(sessionName) {
    if (!confirm(`Delete session "${sessionName}"? This cannot be undone.`)) {
        return;
    }

    try {
        const response = await apiFetch(`/api/sessions/${encodeURIComponent(sessionName)}`, {
            method: 'DELETE'
        });

        if (!response.ok) {
            try {
                const error = await response.json();
                alert(error.detail || 'Failed to delete session');
            } catch {
                alert('Failed to delete session');
            }
            return;
        }

        // Refresh the sessions list in the panel
        refreshSessionsList();

        // Also refresh the welcome page dropdown
        const sessionsData = await fetchSessions();
        const select = document.getElementById('existingSessionSelect');
        if (select) {
            select.innerHTML = '<option value="">-- Select session --</option>';
            sessionsData.sessions.forEach(session => {
                const option = document.createElement('option');
                option.value = session.name;
                option.textContent = `${session.name} (${formatDate(session.modified)})`;
                select.appendChild(option);
            });
        }
    } catch (error) {
        console.error('Error deleting session:', error);
        alert('Failed to delete session');
    }
}


function initializeSessionListeners() {
    // Welcome page session selector
    const createBtn = document.getElementById('createSessionBtn');
    const newNameInput = document.getElementById('newSessionName');
    const existingSelect = document.getElementById('existingSessionSelect');

    // Pre-populate with a cool random name
    if (newNameInput) {
        generateSessionName().then(name => newNameInput.value = name);
    }

    // Regenerate button
    const regenerateBtn = document.getElementById('regenerateNameBtn');
    if (regenerateBtn && newNameInput) {
        regenerateBtn.addEventListener('click', async () => {
            newNameInput.value = await generateSessionName();
        });
    }

    if (createBtn) {
        createBtn.addEventListener('click', async () => {
            const name = newNameInput?.value.trim();
            if (name) {
                createSession(name);
            } else {
                // Auto-generate name
                createSession(await generateSessionName());
            }
        });
    }

    if (newNameInput) {
        newNameInput.addEventListener('keydown', (e) => {
            if (e.key === 'Enter') {
                createBtn?.click();
            }
        });
    }

    if (existingSelect) {
        existingSelect.addEventListener('change', () => {
            const name = existingSelect.value;
            if (name) {
                selectSession(name);
            }
        });
    }

    // Sessions panel handlers are set up at the end of the file with other panels

    // Panel rename button
    const renameBtn = document.getElementById('renameSessionBtn');
    const renameInput = document.getElementById('currentSessionRename');

    if (renameBtn && renameInput) {
        renameBtn.addEventListener('click', () => {
            const newName = renameInput.value.trim();
            if (newName && newName !== currentSession) {
                renameSession(currentSession, newName);
            }
        });
    }

    // Panel create new session
    const panelCreateBtn = document.getElementById('panelCreateSessionBtn');
    const panelNewNameInput = document.getElementById('panelNewSessionName');
    const panelRegenerateBtn = document.getElementById('panelRegenerateNameBtn');

    // Pre-populate panel input with cool name too
    if (panelNewNameInput) {
        generateSessionName().then(name => panelNewNameInput.value = name);
    }

    // Panel regenerate button
    if (panelRegenerateBtn && panelNewNameInput) {
        panelRegenerateBtn.addEventListener('click', async () => {
            panelNewNameInput.value = await generateSessionName();
        });
    }

    if (panelCreateBtn) {
        panelCreateBtn.addEventListener('click', async () => {
            const name = panelNewNameInput?.value.trim();
            if (name) {
                resetLocalState();
                await createSession(name);
                // Pre-populate a new name for next time
                if (panelNewNameInput) {
                    panelNewNameInput.value = await generateSessionName();
                }
            }
        });
    }
}