var cursor_img = $(img#cursor);
is_file_transfer = handler.is_file_transfer();
var is_port_forward = handler.is_port_forward();
var input_blocked = false;
var display_width = 0;
var display_height = 0;
var display_origin_x = 0;
var display_origin_y = 0;
var display_scale = 1;
var keyboard_enabled = true; // server side
var clipboard_enabled = true; // server side
var audio_enabled = true; // server side
var file_enabled = true; // server side
var scroll_body = $(body);

handler.setDisplay = function(x, y, w, h) {
    display_width = w;
    display_height = h;
    display_origin_x = x;
    display_origin_y = y;
    adaptDisplay();
}

function adaptDisplay() {
    var w = display_width;
    var h = display_height;
    if (!w || !h) return;
    var style = handler.get_view_style();
    display_scale = 1.;
    var (sx, sy, sw, sh) = view.screenBox(view.windowState == View.WINDOW_FULL_SCREEN ? #frame : #workarea, #rectw);
    if (sw >= w && sh > h) {
        var hh = $(header).box(#height, #border);
        var el = $(div#adjust-window);
        if (sh > h + hh && el) {
            el.style.set{ display: "block" };
            el = $(li#adjust-window);
            el.style.set{ display: "block" };
            el.onClick = function() {
                view.windowState == View.WINDOW_SHOWN;
                var (x, y) = view.box(#position, #border, #screen);
                // extra for border
                var extra = 2;
                view.move(x, y, w + extra, h + hh + extra);
            }
        }
    }
    if (style != "original") {
        var bw = $(body).box(#width, #border);
        var bh = $(body).box(#height, #border);
        if (view.windowState == View.WINDOW_FULL_SCREEN) {
            bw = sw;
            bh = sh;
        }
        if (bw > 0 && bh > 0) {
            var scale_x = bw.toFloat() / w;
            var scale_y = bh.toFloat() / h;
            var scale = scale_x < scale_y ? scale_x : scale_y;
            if ((scale > 1 && style == "stretch") ||
                (scale < 1 && style == "shrink")) {
                display_scale = scale;
                w = w * scale;
                h = h * scale;
            }
        }
    }
    handler.style.set {
        width: w + "px",
        height: h + "px",
    };
}

// https://sciter.com/event-handling/
// https://sciter.com/docs/content/sciter/Event.htm

var entered = false;
if (!is_file_transfer && !is_port_forward) {
    self.onKey = function(evt) {
        if (!entered) return false;
        // so that arrow key not move scrollbar
        return true; 
    }
}

var wait_window_toolbar = false;
var last_mouse_mask;
var acc_wheel_delta_x = 0;
var acc_wheel_delta_y = 0;
var last_wheel_time = 0;
var inertia_velocity_x = 0;
var inertia_velocity_y = 0;
var acc_wheel_delta_x0 = 0;
var acc_wheel_delta_y0 = 0;
var total_wheel_time = 0;
var wheeling = false;
var dragging = false;

// https://stackoverflow.com/questions/5833399/calculating-scroll-inertia-momentum
function resetWheel() {
    acc_wheel_delta_x = 0;
    acc_wheel_delta_y = 0;
    last_wheel_time = 0;
    inertia_velocity_x = 0;
    inertia_velocity_y = 0;
    acc_wheel_delta_x0 = 0;
    acc_wheel_delta_y0 = 0;
    total_wheel_time = 0;
    wheeling = false;
}

var INERTIA_ACCELERATION = 30;

// not good, precision not enough to simulate accelation effect,
// seems have to use pixel based rather line based delta
function accWheel(v, is_x) {
    if (wheeling) return;
    var abs_v = Math.abs(v);
    var max_t = abs_v / INERTIA_ACCELERATION;
    for (var t = 0.1; t < max_t; t += 0.1) {
        var d = Math.round((abs_v - t * INERTIA_ACCELERATION / 2) * t).toInteger();
        if (d >= 1) {
            abs_v -= t * INERTIA_ACCELERATION;
            if (v < 0) {
                d = -d;
                v = -abs_v;
            } else {
                v = abs_v;
            }
            handler.send_mouse(3, is_x ? d : 0, !is_x ? d : 0, false, false, false, false);
            accWheel(v, is_x);
            break;
        }
    }
}

function handler.onMouse(evt)
{
    if (is_file_transfer || is_port_forward) return false;
    if (view.windowState == View.WINDOW_FULL_SCREEN && !dragging) {
        var dy = evt.y - scroll_body.scroll(#top);
        if (dy <= 1) {
            if (!wait_window_toolbar) {
                wait_window_toolbar = true;
                self.timer(300ms, function() {
                    if (!wait_window_toolbar) return;
                    var extra = 0;
                    // workaround for stupid Sciter, without this, click
                    // event not triggered on top part of buttons on toolbar
                    if (is_osx) extra = 10; 
                    if (view.windowState == View.WINDOW_FULL_SCREEN) {
                        $(header).style.set {
                          display: "block",
                          padding: (2 * workarea_offset + extra) + "px 0 0 0",
                        };
                    }
                    wait_window_toolbar = false;
                });
            }
        } else {
            wait_window_toolbar = false;
            var h = $(header).style;
            if (dy > 20 && h#display != "none") {
              h.set {
                  display: "none",
              };
            }
        } 
    }
    if (!got_mouse_control) {
        if (Math.abs(evt.x - cur_local_x) > 12 || Math.abs(evt.y - cur_local_y) > 12) {
            got_mouse_control = true;
        } else {
            return;
        }
    }
    var mask = 0;
    var wheel_delta_x;
    var wheel_delta_y;
    switch(evt.type) {
      case Event.MOUSE_DOWN:
        mask = 1;
        dragging = true;
        break; 
      case Event.MOUSE_UP:
        mask = 2;
        dragging = false;
        break;
      case Event.MOUSE_MOVE:
        if (cursor_img.style#display != "none" && keyboard_enabled) {
            cursor_img.style#display = "none";
        }
        if (!keyboard_enabled && !useSystemCursor) {
            updateCursor(true);
        }
        if (keyboard_enabled && useSystemCursor) {
            updateCursor();
        }
        break;
      case Event.MOUSE_WHEEL:
        // mouseWheelDistance = 8 * [currentUserDefs floatForKey:@"com.apple.scrollwheel.scaling"];
        mask = 3; 
        {
            var (dx, dy) = evt.wheelDeltas;
            if (dx > 0) dx = 1;
            else if (dx < 0) dx = -1;
            if (dy > 0) dy = 1;
            else if (dy < 0) dy = -1;
            if (Math.abs(dx) > Math.abs(dy)) {
                dy = 0;
            } else {
                dx = 0;
            }
            acc_wheel_delta_x += dx;
            acc_wheel_delta_y += dy;
            wheel_delta_x = acc_wheel_delta_x.toInteger();
            wheel_delta_y = acc_wheel_delta_y.toInteger();
            acc_wheel_delta_x -= wheel_delta_x;
            acc_wheel_delta_y -= wheel_delta_y;
            var now = getTime();
            var dt = last_wheel_time > 0 ? (now - last_wheel_time) / 1000 : 0;
            if (dt > 0) {
                var vx = dx / dt;
                var vy = dy / dt;
                if (vx != 0 || vy != 0) {
                    inertia_velocity_x = vx;
                    inertia_velocity_y = vy;
                }
            }
            acc_wheel_delta_x0 += dx;
            acc_wheel_delta_y0 += dy;
            total_wheel_time += dt;
            if (dx == 0 && dy == 0) {
                wheeling = false;
                if (dt < 0.1 && total_wheel_time > 0) {
                    var v2 = (acc_wheel_delta_y0 / total_wheel_time) * inertia_velocity_y;
                    if (v2 > 0) {
                        v2 = Math.sqrt(v2);
                        inertia_velocity_y = inertia_velocity_y < 0 ? -v2  : v2;
                        accWheel(inertia_velocity_y, false);
                    }
                    v2 = (acc_wheel_delta_x0 / total_wheel_time) * inertia_velocity_x;
                    if (v2 > 0) {
                        v2 = Math.sqrt(v2);
                        inertia_velocity_x = inertia_velocity_x < 0 ? -v2  : v2;
                        accWheel(inertia_velocity_x, true);
                    }
                }
                resetWheel();
            } else {
                wheeling = true;
            }
            last_wheel_time = now;
            if (wheel_delta_x == 0 && wheel_delta_y == 0) return keyboard_enabled;
        }
        break;
      case Event.MOUSE_DCLICK: // seq: down, up, dclick, up
        mask = 1;
        break;
      case Event.MOUSE_ENTER:
        entered = true;
        stdout.println("enter");
        handler.enter();
        return keyboard_enabled;
      case Event.MOUSE_LEAVE:
        entered = false;
        stdout.println("leave");
        handler.leave();
        return keyboard_enabled;
      default:
        return false;
    }
    var x = evt.x;
    var y = evt.y;
    if (mask != 0) {
        // to gain control of the mouse, user must move mouse
        if (cur_x != x || cur_y != y) {
            return keyboard_enabled;
        }
        // save bandwidth
        x = 0;
        y = 0;
    } else {
        cur_local_x = cur_x = x;
        cur_local_y = cur_y = y;
    }
    if (mask != 3) {
        resetWheel();
    }
    if (!keyboard_enabled) return false;
    x = (x / display_scale).toInteger();
    y = (y / display_scale).toInteger();
    // insert down between two up, osx has this behavior for triple click
    if (last_mouse_mask == 2 && mask == 2) {
        handler.send_mouse((evt.buttons << 3) | 1, x + display_origin_x, y + display_origin_y, evt.altKey,
                evt.ctrlKey, evt.shiftKey, evt.commandKey);
    }
    last_mouse_mask = mask;
    // to-do: altKey, ctrlKey etc
    handler.send_mouse((evt.buttons << 3) | mask,
                mask == 3 ? wheel_delta_x : x + display_origin_x,
                mask == 3 ? wheel_delta_y : y + display_origin_y,
                evt.altKey,
                evt.ctrlKey, evt.shiftKey, evt.commandKey);
    return true;
};

var cur_hotx = 0;
var cur_hoty = 0;
var cur_img = null;
var cur_x = 0;
var cur_y = 0;
var cur_local_x = 0;
var cur_local_y = 0;
var cursors = {};
var image_binded;

function scaleCursorImage(img) {
    var w = (img.width * display_scale).toInteger();
    var h = (img.height * display_scale).toInteger();
    cursor_img.style.set {
        width: w + "px",
        height: h + "px",
    };
    self.bindImage("in-memory:cursor", img);
    if (display_scale == 1) return img;
    function paint(gfx) {
        gfx.drawImage(img, 0, 0, w, h);
    }
    return new Image(w, h, paint);
}

var useSystemCursor = true;
function updateCursor(system=false) {
    stdout.println("Update cursor, system: " + system);
    useSystemCursor= system;
    if (system) {
        handler.style#cursor = undefined;
    } else if (cur_img) {
        handler.style.cursor(cur_img, (cur_hotx * display_scale).toInteger(), (cur_hoty * display_scale).toInteger());
    }
}

handler.setCursorData = function(id, hotx, hoty, width, height, colors) {
    cur_hotx = hotx;
    cur_hoty = hoty;
    var img = Image.fromBytes(colors);
    if (img) {
        image_binded = true;
        cursors[id] = [img, hotx, hoty, width, height];
        img = scaleCursorImage(img);
        if (cursor_img.style#display == 'none') {
            self.timer(1ms, updateCursor);
        }
        cur_img = img;
    }
}

handler.setCursorId = function(id) {
    var img = cursors[id];
    if (img) {
        image_binded = true;
        cur_hotx = img[1];
        cur_hoty = img[2];
        img = scaleCursorImage(img[0]);
        if (cursor_img.style#display == 'none') {
            self.timer(1ms, updateCursor);
        }
        cur_img = img;
    }
}

var got_mouse_control = true;
handler.setCursorPosition = function(x, y) {
    if (!image_binded) return;
    got_mouse_control = false;
    cur_x = x - display_origin_x;
    cur_y = y - display_origin_y;
    var x = cur_x - cur_hotx;
    var y = cur_y - cur_hoty;
    x *= display_scale;
    y *= display_scale;
    cursor_img.style.set {
        left: x + "px",
        top: y + "px",
    };
    if (cursor_img.style#display == 'none') {
        cursor_img.style#display = "block";
    }
}

function self.ready() {
    var w = 960;
    var h = 640;
    if (is_file_transfer || is_port_forward) {
        var r = handler.get_size();
        if (isReasonableSize(r) && r[2] > 0) {
            view.move(r[0], r[1], r[2], r[3]);
        } else {
            centerize(w, h);
        }
    } else {
        centerize(w, h);
    }
    if (!is_port_forward) connecting();
    if (is_file_transfer) initializeFileTransfer();
    if (is_port_forward) initializePortForward();
}

var workarea_offset = 0;
var size_adapted;
handler.adaptSize = function() {
    if (size_adapted) return;
    size_adapted = true;
    var (sx, sy, sw, sh) = view.screenBox(#workarea, #rectw);
    var (fx, fy, fw, fh) = view.screenBox(#frame, #rectw);
    if (is_osx) workarea_offset = sy;
    var r = handler.get_size();
    if (isReasonableSize(r) && r[2] > 0) {
        if (r[2] >= fw && r[3] >= fh && !is_linux) {
            view.windowState = View.WINDOW_FULL_SCREEN;
            stdout.println("Initialize to full screen");
        } else if (r[2] >= sw && r[3] >= sh) {
            view.windowState = View.WINDOW_MAXIMIZED;
            stdout.println("Initialize to full screen");
        } else {
            view.move(r[0], r[1], r[2], r[3]);
        }
    } else {
        var w = handler.box(#width, #border)
        var h = handler.box(#height, #border)
        if (w >= sw || h >= sh) {
            view.windowState = View.WINDOW_MAXIMIZED;
            return;
        }
        // extra for border
        var extra = 2;
        centerize(w + extra, handler.box(#height, #border) + h + extra);
    }
}

function self.closing() {
    var (x, y, w, h) = view.box(#rectw, #border, #screen);
    if (is_file_transfer) save_file_transfer_close_state();
    if (is_file_transfer || is_port_forward || size_adapted) handler.save_size(x, y, w, h);
}

handler.setPermission = function(name, enabled) {
    if (name == "keyboard") keyboard_enabled = enabled;
    if (name == "audio") audio_enabled = enabled;
    if (name == "file") file_enabled = enabled;
    if (name == "clipboard") clipboard_enabled = enabled;
    input_blocked = false;
    header.update();
}

handler.closeSuccess = function() {
    // handler.msgbox("success", "Successful", "Ready to go.");
    handler.msgbox("", "", "");
}