/* Atlus — Terminal app (xterm.js + persistent PTY sessions) */
(function () {
    'use strict';

    let sessions = [];  // {terminalId, ws, term, fitAddon, title}
    let activeTerminalId = null;
    let container = null;
    let termContainer = null;
    let tabsContainer = null;
    let kbdVisible = true;
    let resizeObserver = null;

    // ---- Create or attach to a terminal ----

    async function createNewTerminal() {
        // Ask backend to create a persistent terminal
        try {
            const res = await Atlus.apiFetch('/api/session/terminals', {
                method: 'POST',
                body: { cols: 120, rows: 30 },
            });
            if (!res.ok) return null;
            const data = await res.json();
            return attachToTerminal(data.terminal_id, data.title);
        } catch (e) {
            console.error('Failed to create terminal:', e);
            return null;
        }
    }

    function attachToTerminal(terminalId, title) {
        // Don't attach twice
        const existing = sessions.find(s => s.terminalId === terminalId);
        if (existing) {
            switchSession(terminalId);
            return existing;
        }

        const term = new Terminal({
            cursorBlink: true,
            fontSize: 14,
            fontFamily: "'IBM Plex Mono', monospace",
            theme: {
                background: '#111318',
                foreground: '#c8ccd8',
                cursor: '#6ea6f0',
                selectionBackground: 'rgba(110, 166, 240, 0.3)',
                black: '#0d0f14',
                red: '#e05a4a',
                green: '#3ab86a',
                yellow: '#e09a2a',
                blue: '#6ea6f0',
                magenta: '#c678dd',
                cyan: '#56b6c2',
                white: '#c8ccd8',
                brightBlack: '#4a5068',
                brightRed: '#e05a4a',
                brightGreen: '#3ab86a',
                brightYellow: '#e09a2a',
                brightBlue: '#6ea6f0',
                brightMagenta: '#c678dd',
                brightCyan: '#56b6c2',
                brightWhite: '#ffffff',
            },
            allowProposedApi: true,
        });

        const fitAddon = new FitAddon.FitAddon();
        term.loadAddon(fitAddon);

        // Connect WebSocket to the persistent terminal
        const wsUrl = Atlus.wsUrl(`/api/terminal/ws?terminal_id=${terminalId}`);
        const ws = new WebSocket(wsUrl);

        ws.onopen = () => {
            setTimeout(() => {
                fitAddon.fit();
                ws.send(JSON.stringify({
                    type: 'resize',
                    cols: term.cols,
                    rows: term.rows,
                }));
            }, 100);
        };

        ws.onmessage = (e) => {
            const msg = JSON.parse(e.data);
            if (msg.type === 'output') {
                term.write(msg.data);
            } else if (msg.type === 'scrollback') {
                // Replay scrollback from server
                term.write(msg.data);
            } else if (msg.type === 'error') {
                term.write(`\r\n\x1b[31m[Error: ${msg.data}]\x1b[0m\r\n`);
            }
        };

        ws.onclose = () => {
            term.write('\r\n\x1b[33m[Disconnected — refresh to reconnect]\x1b[0m\r\n');
        };

        // Send input to PTY
        term.onData((data) => {
            if (ws.readyState === WebSocket.OPEN) {
                ws.send(JSON.stringify({ type: 'input', data }));
            }
        });

        // Handle resize
        term.onResize(({ cols, rows }) => {
            if (ws.readyState === WebSocket.OPEN) {
                ws.send(JSON.stringify({ type: 'resize', cols, rows }));
            }
        });

        const session = { terminalId, ws, term, fitAddon, title: title || 'Shell' };
        sessions.push(session);

        // Connect on-screen keyboard
        if (Atlus.keyboard) {
            Atlus.keyboard.setTerminal({
                input: (data) => {
                    if (ws.readyState === WebSocket.OPEN) {
                        ws.send(JSON.stringify({ type: 'input', data }));
                    }
                },
            });
        }

        return session;
    }

    function switchSession(terminalId) {
        activeTerminalId = terminalId;
        renderTabs();
        renderTerminal();
        if (Atlus.saveDesktopState) Atlus.saveDesktopState();
    }

    async function closeSession(terminalId) {
        const idx = sessions.findIndex(s => s.terminalId === terminalId);
        if (idx === -1) return;

        const session = sessions[idx];

        // Close WebSocket (doesn't kill PTY)
        if (session.ws.readyState === WebSocket.OPEN) {
            session.ws.close();
        }
        session.term.dispose();
        sessions.splice(idx, 1);

        // Tell server to kill the PTY
        try {
            await Atlus.apiFetch(`/api/session/terminals/${terminalId}`, {
                method: 'DELETE',
            });
        } catch (e) { /* best effort */ }

        if (sessions.length === 0) {
            Atlus.closeApp('terminal');
            return;
        }

        if (activeTerminalId === terminalId) {
            activeTerminalId = sessions[sessions.length - 1].terminalId;
        }
        renderTabs();
        renderTerminal();
        if (Atlus.saveDesktopState) Atlus.saveDesktopState();
    }

    function renderTabs() {
        if (!tabsContainer) return;
        tabsContainer.innerHTML = '';
        sessions.forEach((s, i) => {
            const tab = document.createElement('button');
            tab.className = 'terminal-tab' + (s.terminalId === activeTerminalId ? ' active' : '');
            tab.innerHTML = `<span>${s.title || 'Shell ' + (i + 1)}</span>`;
            if (sessions.length > 1) {
                tab.innerHTML += `<span class="terminal-tab-close">&times;</span>`;
            }
            tab.addEventListener('click', (e) => {
                if (e.target.classList.contains('terminal-tab-close')) {
                    closeSession(s.terminalId);
                } else {
                    switchSession(s.terminalId);
                }
            });
            tabsContainer.appendChild(tab);
        });
    }

    function renderTerminal() {
        if (!termContainer) return;
        termContainer.innerHTML = '';

        const session = sessions.find(s => s.terminalId === activeTerminalId);
        if (!session) return;

        const wrap = document.createElement('div');
        wrap.className = 'terminal-container';
        termContainer.appendChild(wrap);
        session.term.open(wrap);

        requestAnimationFrame(() => {
            session.fitAddon.fit();
        });

        // Update keyboard terminal ref
        if (Atlus.keyboard) {
            Atlus.keyboard.setTerminal({
                input: (data) => {
                    if (session.ws.readyState === WebSocket.OPEN) {
                        session.ws.send(JSON.stringify({ type: 'input', data }));
                    }
                },
            });
        }
    }

    // ---- Session restore logic ----

    async function initTerminals() {
        const restored = Atlus._restoredTerminals || [];
        const tabInfo = Atlus._restoredTerminalTabs || [];

        if (restored.length > 0) {
            // Re-attach to existing server-side terminals
            for (const t of restored) {
                // Find title from tab info if available
                const info = tabInfo.find(ti => ti.terminal_id === t.terminal_id);
                const title = (info && info.title) || t.title || 'Shell';
                attachToTerminal(t.terminal_id, title);
            }
            if (sessions.length > 0) {
                activeTerminalId = sessions[0].terminalId;
            }
        }

        // If no terminals were restored, create a fresh one
        if (sessions.length === 0) {
            const s = await createNewTerminal();
            if (s) activeTerminalId = s.terminalId;
        }

        // Clear restored data so re-opening terminal app doesn't double-attach
        delete Atlus._restoredTerminals;
        delete Atlus._restoredTerminalTabs;

        renderTabs();
        renderTerminal();
    }

    // ---- App registration ----

    Atlus.registerApp('terminal', {
        title: 'Terminal',

        init(el) {
            container = el;
            container.classList.add('app-terminal');

            // Toolbar
            const toolbar = document.createElement('div');
            toolbar.className = 'terminal-toolbar';

            tabsContainer = document.createElement('div');
            tabsContainer.className = 'terminal-tabs';
            toolbar.appendChild(tabsContainer);

            const newTabBtn = document.createElement('button');
            newTabBtn.className = 'terminal-new-tab';
            newTabBtn.textContent = '+';
            newTabBtn.title = 'New tab';
            newTabBtn.addEventListener('click', async () => {
                const s = await createNewTerminal();
                if (s) switchSession(s.terminalId);
            });
            toolbar.appendChild(newTabBtn);

            const kbdBtn = document.createElement('button');
            kbdBtn.className = 'terminal-kbd-toggle' + (kbdVisible ? ' active' : '');
            kbdBtn.textContent = '⌨';
            kbdBtn.title = 'Toggle keyboard';
            kbdBtn.addEventListener('click', () => {
                kbdVisible = !kbdVisible;
                kbdBtn.classList.toggle('active', kbdVisible);
                if (Atlus.keyboard) Atlus.keyboard.toggle();
                const session = sessions.find(s => s.terminalId === activeTerminalId);
                if (session) {
                    requestAnimationFrame(() => session.fitAddon.fit());
                }
            });
            toolbar.appendChild(kbdBtn);

            container.appendChild(toolbar);

            // Terminal area
            termContainer = document.createElement('div');
            termContainer.style.flex = '1';
            termContainer.style.overflow = 'hidden';
            termContainer.style.display = 'flex';
            termContainer.style.flexDirection = 'column';
            container.appendChild(termContainer);

            // On-screen keyboard
            if (Atlus.keyboard) {
                const kbdEl = Atlus.keyboard.create();
                if (!kbdVisible) kbdEl.classList.add('hidden');
                container.appendChild(kbdEl);
            }

            // Initialize — restore or create terminals
            initTerminals();

            // Resize observer
            resizeObserver = new ResizeObserver(() => {
                const session = sessions.find(s => s.terminalId === activeTerminalId);
                if (session) {
                    try { session.fitAddon.fit(); } catch (e) {}
                }
            });
            resizeObserver.observe(termContainer);
        },

        destroy() {
            if (resizeObserver) {
                resizeObserver.disconnect();
                resizeObserver = null;
            }
            // Close WebSockets but do NOT kill PTYs — they persist on server
            sessions.forEach(s => {
                if (s.ws.readyState === WebSocket.OPEN) s.ws.close();
                s.term.dispose();
            });
            sessions = [];
            activeTerminalId = null;
            container = null;
            termContainer = null;
            tabsContainer = null;
        },

        onFocus() {
            const session = sessions.find(s => s.terminalId === activeTerminalId);
            if (session) {
                requestAnimationFrame(() => {
                    session.fitAddon.fit();
                    session.term.focus();
                });
            }
        },

        /** Public API: get terminal IDs for session state saving */
        getTerminalIds() {
            return sessions.map(s => ({
                terminal_id: s.terminalId,
                title: s.title,
            }));
        },
    });
})();