use std::collections::vec_deque::IntoIter as VecDequeIter;

use {
    CreationError,
    EventsLoop,
    Icon,
    LogicalPosition,
    LogicalSize,
    MouseCursor,
    PhysicalPosition,
    PhysicalSize,
    platform,
    Window,
    WindowBuilder,
    WindowId,
};

impl WindowBuilder {
    /// Initializes a new `WindowBuilder` with default values.
    #[inline]
    pub fn new() -> WindowBuilder {
        WindowBuilder {
            window: Default::default(),
            platform_specific: Default::default(),
        }
    }

    /// Requests the window to be of specific dimensions.
    #[inline]
    pub fn with_dimensions(mut self, size: LogicalSize) -> WindowBuilder {
        self.window.dimensions = Some(size);
        self
    }

    /// Sets a minimum dimension size for the window
    #[inline]
    pub fn with_min_dimensions(mut self, min_size: LogicalSize) -> WindowBuilder {
        self.window.min_dimensions = Some(min_size);
        self
    }

    /// Sets a maximum dimension size for the window
    #[inline]
    pub fn with_max_dimensions(mut self, max_size: LogicalSize) -> WindowBuilder {
        self.window.max_dimensions = Some(max_size);
        self
    }

    /// Sets whether the window is resizable or not
    ///
    /// Note that making the window unresizable doesn't exempt you from handling `Resized`, as that event can still be
    /// triggered by DPI scaling, entering fullscreen mode, etc.
    ///
    /// ## Platform-specific
    ///
    /// This only has an effect on desktop platforms.
    ///
    /// Due to a bug in XFCE, this has no effect on Xfwm.
    #[inline]
    pub fn with_resizable(mut self, resizable: bool) -> WindowBuilder {
        self.window.resizable = resizable;
        self
    }

    /// Requests a specific title for the window.
    #[inline]
    pub fn with_title<T: Into<String>>(mut self, title: T) -> WindowBuilder {
        self.window.title = title.into();
        self
    }

    /// Sets the window fullscreen state. None means a normal window, Some(MonitorId)
    /// means a fullscreen window on that specific monitor
    #[inline]
    pub fn with_fullscreen(mut self, monitor: Option<MonitorId>) -> WindowBuilder {
        self.window.fullscreen = monitor;
        self
    }

    /// Requests maximized mode.
    #[inline]
    pub fn with_maximized(mut self, maximized: bool) -> WindowBuilder {
        self.window.maximized = maximized;
        self
    }

    /// Sets whether the window will be initially hidden or visible.
    #[inline]
    pub fn with_visibility(mut self, visible: bool) -> WindowBuilder {
        self.window.visible = visible;
        self
    }

    /// Sets whether the background of the window should be transparent.
    #[inline]
    pub fn with_transparency(mut self, transparent: bool) -> WindowBuilder {
        self.window.transparent = transparent;
        self
    }

    /// Sets whether the window should have a border, a title bar, etc.
    #[inline]
    pub fn with_decorations(mut self, decorations: bool) -> WindowBuilder {
        self.window.decorations = decorations;
        self
    }

    /// Sets whether or not the window will always be on top of other windows.
    #[inline]
    pub fn with_always_on_top(mut self, always_on_top: bool) -> WindowBuilder {
        self.window.always_on_top = always_on_top;
        self
    }

    /// Sets the window icon. On Windows and X11, this is typically the small icon in the top-left
    /// corner of the titlebar.
    ///
    /// ## Platform-specific
    ///
    /// This only has an effect on Windows and X11.
    ///
    /// On Windows, this sets `ICON_SMALL`. The base size for a window icon is 16x16, but it's
    /// recommended to account for screen scaling and pick a multiple of that, i.e. 32x32.
    ///
    /// X11 has no universal guidelines for icon sizes, so you're at the whims of the WM. That
    /// said, it's usually in the same ballpark as on Windows.
    #[inline]
    pub fn with_window_icon(mut self, window_icon: Option<Icon>) -> WindowBuilder {
        self.window.window_icon = window_icon;
        self
    }

    /// Enables multitouch.
    #[inline]
    pub fn with_multitouch(mut self) -> WindowBuilder {
        self.window.multitouch = true;
        self
    }

    /// Builds the window.
    ///
    /// Error should be very rare and only occur in case of permission denied, incompatible system,
    /// out of memory, etc.
    #[inline]
    pub fn build(mut self, events_loop: &EventsLoop) -> Result<Window, CreationError> {
        self.window.dimensions = Some(self.window.dimensions.unwrap_or_else(|| {
            if let Some(ref monitor) = self.window.fullscreen {
                // resizing the window to the dimensions of the monitor when fullscreen
                LogicalSize::from_physical(monitor.get_dimensions(), 1.0)
            } else {
                // default dimensions
                (1024, 768).into()
            }
        }));

        // building
        platform::Window::new(
            &events_loop.events_loop,
            self.window,
            self.platform_specific,
        ).map(|window| Window { window })
    }
}

impl Window {
    /// Creates a new Window for platforms where this is appropriate.
    ///
    /// This function is equivalent to `WindowBuilder::new().build(events_loop)`.
    ///
    /// Error should be very rare and only occur in case of permission denied, incompatible system,
    ///  out of memory, etc.
    #[inline]
    pub fn new(events_loop: &EventsLoop) -> Result<Window, CreationError> {
        let builder = WindowBuilder::new();
        builder.build(events_loop)
    }

    /// Modifies the title of the window.
    ///
    /// This is a no-op if the window has already been closed.
    #[inline]
    pub fn set_title(&self, title: &str) {
        self.window.set_title(title)
    }

    /// Shows the window if it was hidden.
    ///
    /// ## Platform-specific
    ///
    /// - Has no effect on Android
    ///
    #[inline]
    pub fn show(&self) {
        self.window.show()
    }

    /// Hides the window if it was visible.
    ///
    /// ## Platform-specific
    ///
    /// - Has no effect on Android
    ///
    #[inline]
    pub fn hide(&self) {
        self.window.hide()
    }

    /// Returns the position of the top-left hand corner of the window relative to the
    ///  top-left hand corner of the desktop.
    ///
    /// Note that the top-left hand corner of the desktop is not necessarily the same as
    ///  the screen. If the user uses a desktop with multiple monitors, the top-left hand corner
    ///  of the desktop is the top-left hand corner of the monitor at the top-left of the desktop.
    ///
    /// The coordinates can be negative if the top-left hand corner of the window is outside
    ///  of the visible screen region.
    ///
    /// Returns `None` if the window no longer exists.
    #[inline]
    pub fn get_position(&self) -> Option<LogicalPosition> {
        self.window.get_position()
    }

    /// Returns the position of the top-left hand corner of the window's client area relative to the
    /// top-left hand corner of the desktop.
    ///
    /// The same conditions that apply to `get_position` apply to this method.
    #[inline]
    pub fn get_inner_position(&self) -> Option<LogicalPosition> {
        self.window.get_inner_position()
    }

    /// Modifies the position of the window.
    ///
    /// See `get_position` for more information about the coordinates.
    ///
    /// This is a no-op if the window has already been closed.
    #[inline]
    pub fn set_position(&self, position: LogicalPosition) {
        self.window.set_position(position)
    }

    /// Returns the logical size of the window's client area.
    ///
    /// The client area is the content of the window, excluding the title bar and borders.
    ///
    /// Converting the returned `LogicalSize` to `PhysicalSize` produces the size your framebuffer should be.
    ///
    /// Returns `None` if the window no longer exists.
    #[inline]
    pub fn get_inner_size(&self) -> Option<LogicalSize> {
        self.window.get_inner_size()
    }

    /// Returns the logical size of the entire window.
    ///
    /// These dimensions include the title bar and borders. If you don't want that (and you usually don't),
    /// use `get_inner_size` instead.
    ///
    /// Returns `None` if the window no longer exists.
    #[inline]
    pub fn get_outer_size(&self) -> Option<LogicalSize> {
        self.window.get_outer_size()
    }

    /// Modifies the inner size of the window.
    ///
    /// See `get_inner_size` for more information about the values.
    ///
    /// This is a no-op if the window has already been closed.
    #[inline]
    pub fn set_inner_size(&self, size: LogicalSize) {
        self.window.set_inner_size(size)
    }

    /// Sets a minimum dimension size for the window.
    #[inline]
    pub fn set_min_dimensions(&self, dimensions: Option<LogicalSize>) {
        self.window.set_min_dimensions(dimensions)
    }

    /// Sets a maximum dimension size for the window.
    #[inline]
    pub fn set_max_dimensions(&self, dimensions: Option<LogicalSize>) {
        self.window.set_max_dimensions(dimensions)
    }

    /// Sets whether the window is resizable or not.
    ///
    /// Note that making the window unresizable doesn't exempt you from handling `Resized`, as that event can still be
    /// triggered by DPI scaling, entering fullscreen mode, etc.
    ///
    /// ## Platform-specific
    ///
    /// This only has an effect on desktop platforms.
    ///
    /// Due to a bug in XFCE, this has no effect on Xfwm.
    #[inline]
    pub fn set_resizable(&self, resizable: bool) {
        self.window.set_resizable(resizable)
    }

    /// Returns the DPI factor that can be used to map logical pixels to physical pixels, and vice versa.
    ///
    /// See the [`dpi`](dpi/index.html) module for more information.
    ///
    /// Note that this value can change depending on user action (for example if the window is
    /// moved to another screen); as such, tracking `WindowEvent::HiDpiFactorChanged` events is
    /// the most robust way to track the DPI you need to use to draw.
    ///
    /// ## Platform-specific
    ///
    /// - **X11:** Can be overridden using the `WINIT_HIDPI_FACTOR` environment variable.
    /// - **Android:** Always returns 1.0.
    #[inline]
    pub fn get_hidpi_factor(&self) -> f64 {
        self.window.get_hidpi_factor()
    }

    /// Modifies the mouse cursor of the window.
    /// Has no effect on Android.
    #[inline]
    pub fn set_cursor(&self, cursor: MouseCursor) {
        self.window.set_cursor(cursor);
    }

    /// Changes the position of the cursor in window coordinates.
    #[inline]
    pub fn set_cursor_position(&self, position: LogicalPosition) -> Result<(), String> {
        self.window.set_cursor_position(position)
    }

    /// Grabs the cursor, preventing it from leaving the window.
    ///
    /// ## Platform-specific
    ///
    /// On macOS, this presently merely locks the cursor in a fixed location, which looks visually awkward.
    ///
    /// This has no effect on Android or iOS.
    #[inline]
    pub fn grab_cursor(&self, grab: bool) -> Result<(), String> {
        self.window.grab_cursor(grab)
    }

    /// Hides the cursor, making it invisible but still usable.
    ///
    /// ## Platform-specific
    ///
    /// On Windows and X11, the cursor is only hidden within the confines of the window.
    ///
    /// On macOS, the cursor is hidden as long as the window has input focus, even if the cursor is outside of the
    /// window.
    ///
    /// This has no effect on Android or iOS.
    #[inline]
    pub fn hide_cursor(&self, hide: bool) {
        self.window.hide_cursor(hide)
    }

    /// Sets the window to maximized or back
    #[inline]
    pub fn set_maximized(&self, maximized: bool) {
        self.window.set_maximized(maximized)
    }

    /// Sets the window to fullscreen or back
    #[inline]
    pub fn set_fullscreen(&self, monitor: Option<MonitorId>) {
        self.window.set_fullscreen(monitor)
    }

    /// Turn window decorations on or off.
    #[inline]
    pub fn set_decorations(&self, decorations: bool) {
        self.window.set_decorations(decorations)
    }

    /// Change whether or not the window will always be on top of other windows.
    #[inline]
    pub fn set_always_on_top(&self, always_on_top: bool) {
        self.window.set_always_on_top(always_on_top)
    }

    /// Sets the window icon. On Windows and X11, this is typically the small icon in the top-left
    /// corner of the titlebar.
    ///
    /// For more usage notes, see `WindowBuilder::with_window_icon`.
    ///
    /// ## Platform-specific
    ///
    /// This only has an effect on Windows and X11.
    #[inline]
    pub fn set_window_icon(&self, window_icon: Option<Icon>) {
        self.window.set_window_icon(window_icon)
    }

    /// Sets location of IME candidate box in client area coordinates relative to the top left.
    #[inline]
    pub fn set_ime_spot(&self, position: LogicalPosition) {
        self.window.set_ime_spot(position)
    }

    /// Returns the monitor on which the window currently resides
    #[inline]
    pub fn get_current_monitor(&self) -> MonitorId {
        self.window.get_current_monitor()
    }

    /// Returns the list of all the monitors available on the system.
    ///
    /// This is the same as `EventsLoop::get_available_monitors`, and is provided for convenience.
    #[inline]
    pub fn get_available_monitors(&self) -> AvailableMonitorsIter {
        let data = self.window.get_available_monitors();
        AvailableMonitorsIter { data: data.into_iter() }
    }

    /// Returns the primary monitor of the system.
    ///
    /// This is the same as `EventsLoop::get_primary_monitor`, and is provided for convenience.
    #[inline]
    pub fn get_primary_monitor(&self) -> MonitorId {
        MonitorId { inner: self.window.get_primary_monitor() }
    }

    #[inline]
    pub fn id(&self) -> WindowId {
        WindowId(self.window.id())
    }
}

/// An iterator for the list of available monitors.
// Implementation note: we retrieve the list once, then serve each element by one by one.
// This may change in the future.
#[derive(Debug)]
pub struct AvailableMonitorsIter {
    pub(crate) data: VecDequeIter<platform::MonitorId>,
}

impl Iterator for AvailableMonitorsIter {
    type Item = MonitorId;

    #[inline]
    fn next(&mut self) -> Option<MonitorId> {
        self.data.next().map(|id| MonitorId { inner: id })
    }

    #[inline]
    fn size_hint(&self) -> (usize, Option<usize>) {
        self.data.size_hint()
    }
}

/// Identifier for a monitor.
#[derive(Debug, Clone)]
pub struct MonitorId {
    pub(crate) inner: platform::MonitorId
}

impl MonitorId {
    /// Returns a human-readable name of the monitor.
    ///
    /// Returns `None` if the monitor doesn't exist anymore.
    #[inline]
    pub fn get_name(&self) -> Option<String> {
        self.inner.get_name()
    }

    /// Returns the monitor's resolution.
    #[inline]
    pub fn get_dimensions(&self) -> PhysicalSize {
        self.inner.get_dimensions()
    }

    /// Returns the top-left corner position of the monitor relative to the larger full
    /// screen area.
    #[inline]
    pub fn get_position(&self) -> PhysicalPosition {
        self.inner.get_position()
    }

    /// Returns the DPI factor that can be used to map logical pixels to physical pixels, and vice versa.
    ///
    /// See the [`dpi`](dpi/index.html) module for more information.
    ///
    /// ## Platform-specific
    ///
    /// - **X11:** This respects Xft.dpi XResource, and can be overridden using the `WINIT_HIDPI_FACTOR` environment variable.
    /// - **Android:** Always returns 1.0.
    #[inline]
    pub fn get_hidpi_factor(&self) -> f64 {
        self.inner.get_hidpi_factor()
    }
}