var sshTerm = null;
var sshFit = null;
var sshWS = null;
var sshResizeTimer = null;

function initPage8() {
    var el = document.getElementById("ssh-terminal");
    if (!el || sshTerm) {
        return;
    }
    // xterm.js 不支持 IE 等老浏览器, 优雅降级提示
    if (typeof Terminal === "undefined") {
        el.innerHTML =
            '<div style="padding:24px;text-align:center;color:#94a3b8;line-height:1.8;">' +
            "当前浏览器不支持 SSH 终端组件。<br>" +
            "请使用 Chrome、Edge、Firefox 等现代浏览器访问该功能。</div>";
        return;
    }
    sshTerm = new Terminal({
        cursorBlink: true,
        scrollback: 2000,
        fontSize: 14,
        convertEol: true,
        theme: {
            background: "#111111",
        },
    });
    sshFit = new FitAddon.FitAddon();
    sshTerm.loadAddon(sshFit);
    sshTerm.open(el);
    sshTerm.onData(function (data) {
        if ((sshWS && sshWS.readyState) === WebSocket.OPEN) {
            sshWS.send(
                JSON.stringify({
                    type: "input",
                    data: data,
                })
            );
        }
    });
    connectSSH();
    window.addEventListener("resize", resizeSSH);
    resizeSSH();
}

function connectSSH() {
    sshWS = new WebSocket(
        (location.protocol === "https:" ? "wss://" : "ws://") + location.host + "/api/ssh/ws"
    );
    sshWS.binaryType = "arraybuffer";
    sshWS.onopen = function () {
        resizeSSH();
        sshTerm && sshTerm.focus();
    };
    sshWS.onmessage = function (e) {
        sshTerm && sshTerm.write(new Uint8Array(e.data));
    };
    sshWS.onclose = function () {
        sshWS = null;
        sshTerm && sshTerm.write("\r\n\x1b[33m[Connection closed]\x1b[0m\r\n");
    };
}

function resizeSSH() {
    if (!sshFit || !sshTerm) {
        return;
    }
    clearTimeout(sshResizeTimer);
    sshResizeTimer = null;
    sshResizeTimer = setTimeout(function () {
        if (!sshTerm || !sshFit) {
            return;
        }
        sshFit.fit();
        if ((sshWS && sshWS.readyState) === WebSocket.OPEN) {
            sshWS.send(
                JSON.stringify({
                    type: "resize",
                    cols: sshTerm.cols,
                    rows: sshTerm.rows,
                })
            );
        }
    }, 100);
}

function exitPage8() {
    window.removeEventListener("resize", resizeSSH);
    clearTimeout(sshResizeTimer);
    if (sshWS) {
        sshWS.onclose = null;
        sshWS.close();
        sshWS = null;
    }
    sshTerm && sshTerm.dispose();
    sshTerm = null;
    sshFit = null;
}