var term;
var ws;
var connected = false;
var binary_state = 0;
var put_file_name = null;
var put_file_data = null;
var get_file_name = null;
var get_file_data = null;

function calculate_size(win) {
    var cols = Math.max(80, Math.min(150, (win.innerWidth - 280) / 7)) | 0;
    var rows = Math.max(24, Math.min(80, (win.innerHeight - 180) / 12)) | 0;
    return [cols, rows];
}

(function() {
    window.onload = function() {
      var url = window.location.hash.substring(1);
      if (!url) {
          // pre-populate the url based on the host that served this page.
          url = document.location.host;
      }
      document.getElementById('url').value = 'ws://' + url;
      var size = calculate_size(self);
      term = new Terminal({
        cols: size[0],
        rows: size[1],
        useStyle: true,
        screenKeys: true,
        cursorBlink: false
      });
      term.open(document.getElementById("term"));
      show_https_warning();
    };
    window.addEventListener('resize', function() {
        var size = calculate_size(self);
        term.resize(size[0], size[1]);
    });
}).call(this);

function show_https_warning() {
    if (window.location.protocol == 'https:') {
        var warningDiv = document.createElement('div');
        warningDiv.style.cssText = 'background:#f99;padding:5px;margin-bottom:10px;line-height:1.5em;text-align:center';
        warningDiv.innerHTML = [
            'The WebREPL client cannot be accessed over HTTPS connections.',
            'Load the WebREPL client from the device instead.'
        ].join('<br>');
        document.body.insertBefore(warningDiv, document.body.childNodes[0]);
        term.resize(term.cols, term.rows - 7);
    }
}

function button_click() {
    if (connected) {
        ws.close();
    } else {
        document.getElementById('url').disabled = true;
        document.getElementById('button').value = "Disconnect";
        connected = true;
        connect(document.getElementById('url').value);
    }
}

function prepare_for_connect() {
    document.getElementById('url').disabled = false;
    document.getElementById('button').value = "Connect";
}

function update_file_status(s) {
    document.getElementById('file-status').innerHTML = s;
}

function connect(url) {
    var hostport = url.substring(5);
    if (hostport === document.location.host) {
        hostport = '';
    }

    window.location.hash = hostport;
    ws = new WebSocket(url);
    ws.binaryType = 'arraybuffer';
    ws.onopen = function() {
        term.removeAllListeners('data');
        term.on('data', function(data) {
            // Pasted data from clipboard will likely contain
            // LF as EOL chars.
            data = data.replace(/\n/g, "\r");
            ws.send(data);
        });

        term.on('title', function(title) {
            document.title = title;
        });

        term.focus();
        term.element.focus();
        term.write('\x1b[31mWelcome to MicroPython!\x1b[m\r\n');

        ws.onmessage = function(event) {
            if (event.data instanceof ArrayBuffer) {
                var data = new Uint8Array(event.data);
                switch (binary_state) {
                    case 11:
                        // first response for put
                        if (decode_resp(data) == 0) {
                            // send file data in chunks
                            for (var offset = 0; offset < put_file_data.length; offset += 1024) {
                                ws.send(put_file_data.slice(offset, offset + 1024));
                            }
                            binary_state = 12;
                        }
                        break;
                    case 12:
                        // final response for put
                        if (decode_resp(data) == 0) {
                            update_file_status('Sent ' + put_file_name + ', ' + put_file_data.length + ' bytes');
                        } else {
                            update_file_status('Failed sending ' + put_file_name);
                        }
                        binary_state = 0;
                        break;

                    case 21:
                        // first response for get
                        if (decode_resp(data) == 0) {
                            binary_state = 22;
                            var rec = new Uint8Array(1);
                            rec[0] = 0;
                            ws.send(rec);
                        }
                        break;
                    case 22: {
                        // file data
                        var sz = data[0] | (data[1] << 8);
                        if (data.length == 2 + sz) {
                            // we assume that the data comes in single chunks
                            if (sz == 0) {
                                // end of file
                                binary_state = 23;
                            } else {
                                // accumulate incoming data to get_file_data
                                var new_buf = new Uint8Array(get_file_data.length + sz);
                                new_buf.set(get_file_data);
                                new_buf.set(data.slice(2), get_file_data.length);
                                get_file_data = new_buf;
                                update_file_status('Getting ' + get_file_name + ', ' + get_file_data.length + ' bytes');

                                var rec = new Uint8Array(1);
                                rec[0] = 0;
                                ws.send(rec);
                            }
                        } else {
                            binary_state = 0;
                        }
                        break;
                    }
                    case 23:
                        // final response
                        if (decode_resp(data) == 0) {
                            update_file_status('Got ' + get_file_name + ', ' + get_file_data.length + ' bytes');
                            saveAs(new Blob([get_file_data], {type: "application/octet-stream"}), get_file_name);
                        } else {
                            update_file_status('Failed getting ' + get_file_name);
                        }
                        binary_state = 0;
                        break;
                    case 31:
                        // first (and last) response for GET_VER
                        console.log('GET_VER', data);
                        binary_state = 0;
                        break;
                }
            }
            term.write(event.data);
        };
    };

    ws.onclose = function() {
        connected = false;
        if (term) {
            term.write('\x1b[31mDisconnected\x1b[m\r\n');
        }
        term.off('data');
        prepare_for_connect();
    }
}

function decode_resp(data) {
    if (data[0] == 'W'.charCodeAt(0) && data[1] == 'B'.charCodeAt(0)) {
        var code = data[2] | (data[3] << 8);
        return code;
    } else {
        return -1;
    }
}

function put_file() {
    var dest_fname = put_file_name;
    var dest_fsize = put_file_data.length;

    // WEBREPL_FILE = "<2sBBQLH64s"
    var rec = new Uint8Array(2 + 1 + 1 + 8 + 4 + 2 + 64);
    rec[0] = 'W'.charCodeAt(0);
    rec[1] = 'A'.charCodeAt(0);
    rec[2] = 1; // put
    rec[3] = 0;
    rec[4] = 0; rec[5] = 0; rec[6] = 0; rec[7] = 0; rec[8] = 0; rec[9] = 0; rec[10] = 0; rec[11] = 0;
    rec[12] = dest_fsize & 0xff; rec[13] = (dest_fsize >> 8) & 0xff; rec[14] = (dest_fsize >> 16) & 0xff; rec[15] = (dest_fsize >> 24) & 0xff;
    rec[16] = dest_fname.length & 0xff; rec[17] = (dest_fname.length >> 8) & 0xff;
    for (var i = 0; i < 64; ++i) {
        if (i < dest_fname.length) {
            rec[18 + i] = dest_fname.charCodeAt(i);
        } else {
            rec[18 + i] = 0;
        }
    }

    // initiate put
    binary_state = 11;
    update_file_status('Sending ' + put_file_name + '...');
    ws.send(rec);
}

function get_file() {
    var src_fname = document.getElementById('get_filename').value;

    // WEBREPL_FILE = "<2sBBQLH64s"
    var rec = new Uint8Array(2 + 1 + 1 + 8 + 4 + 2 + 64);
    rec[0] = 'W'.charCodeAt(0);
    rec[1] = 'A'.charCodeAt(0);
    rec[2] = 2; // get
    rec[3] = 0;
    rec[4] = 0; rec[5] = 0; rec[6] = 0; rec[7] = 0; rec[8] = 0; rec[9] = 0; rec[10] = 0; rec[11] = 0;
    rec[12] = 0; rec[13] = 0; rec[14] = 0; rec[15] = 0;
    rec[16] = src_fname.length & 0xff; rec[17] = (src_fname.length >> 8) & 0xff;
    for (var i = 0; i < 64; ++i) {
        if (i < src_fname.length) {
            rec[18 + i] = src_fname.charCodeAt(i);
        } else {
            rec[18 + i] = 0;
        }
    }

    // initiate get
    binary_state = 21;
    get_file_name = src_fname;
    get_file_data = new Uint8Array(0);
    update_file_status('Getting ' + get_file_name + '...');
    ws.send(rec);
}

function get_ver() {
    // WEBREPL_REQ_S = "<2sBBQLH64s"
    var rec = new Uint8Array(2 + 1 + 1 + 8 + 4 + 2 + 64);
    rec[0] = 'W'.charCodeAt(0);
    rec[1] = 'A'.charCodeAt(0);
    rec[2] = 3; // GET_VER
    // rest of "rec" is zero

    // initiate GET_VER
    binary_state = 31;
    ws.send(rec);
}

function handle_put_file_select(evt) {
    // The event holds a FileList object which is a list of File objects,
    // but we only support single file selection at the moment.
    var files = evt.target.files;

    // Get the file info and load its data.
    var f = files[0];
    put_file_name = f.name;
    var reader = new FileReader();
    reader.onload = function(e) {
        put_file_data = new Uint8Array(e.target.result);
        document.getElementById('put-file-list').innerHTML = '' + escape(put_file_name) + ' - ' + put_file_data.length + ' bytes';
        document.getElementById('put-file-button').disabled = false;
    };
    reader.readAsArrayBuffer(f);
}

document.getElementById('put-file-select').addEventListener('click', function(){
    this.value = null;
}, false);

document.getElementById('put-file-select').addEventListener('change', handle_put_file_select, false);
document.getElementById('put-file-button').disabled = true;