// Copyright 2019-2021 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0

//! Types useful for interacting with a user's monitors.
//!
//! If you want to get basic information about a monitor, you can use the [`MonitorHandle`][monitor_handle]
//! type. This is retrieved from one of the following methods, which return an iterator of
//! [`MonitorHandle`][monitor_handle]:
//! - [`EventLoopWindowTarget::available_monitors`][loop_get]
//! - [`Window::available_monitors`][window_get].
//!
//! [monitor_handle]: crate::monitor::MonitorHandle
//! [loop_get]: crate::event_loop::EventLoopWindowTarget::available_monitors
//! [window_get]: crate::window::Window::available_monitors
use crate::{
  dpi::{PhysicalPosition, PhysicalSize},
  platform_impl,
};

/// Describes a fullscreen video mode of a monitor.
///
/// Can be acquired with:
/// - [`MonitorHandle::video_modes`][monitor_get].
///
/// [monitor_get]: crate::monitor::MonitorHandle::video_modes
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct VideoMode {
  pub(crate) video_mode: platform_impl::VideoMode,
}

impl std::fmt::Debug for VideoMode {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    self.video_mode.fmt(f)
  }
}

impl PartialOrd for VideoMode {
  fn partial_cmp(&self, other: &VideoMode) -> Option<std::cmp::Ordering> {
    Some(self.cmp(other))
  }
}

impl Ord for VideoMode {
  fn cmp(&self, other: &VideoMode) -> std::cmp::Ordering {
    // TODO: we can impl `Ord` for `PhysicalSize` once we switch from `f32`
    // to `u32` there
    let size: (u32, u32) = self.size().into();
    let other_size: (u32, u32) = other.size().into();
    self.monitor().cmp(&other.monitor()).then(
      size
        .cmp(&other_size)
        .then(
          self
            .refresh_rate()
            .cmp(&other.refresh_rate())
            .then(self.bit_depth().cmp(&other.bit_depth())),
        )
        .reverse(),
    )
  }
}

impl VideoMode {
  /// Returns the resolution of this video mode.
  #[inline]
  pub fn size(&self) -> PhysicalSize<u32> {
    self.video_mode.size()
  }

  /// Returns the bit depth of this video mode, as in how many bits you have
  /// available per color. This is generally 24 bits or 32 bits on modern
  /// systems, depending on whether the alpha channel is counted or not.
  ///
  /// ## Platform-specific
  /// - **iOS:** Always returns 32.
  #[inline]
  pub fn bit_depth(&self) -> u16 {
    self.video_mode.bit_depth()
  }

  /// Returns the refresh rate of this video mode. **Note**: the returned
  /// refresh rate is an integer approximation, and you shouldn't rely on this
  /// value to be exact.
  #[inline]
  pub fn refresh_rate(&self) -> u16 {
    self.video_mode.refresh_rate()
  }

  /// Returns the monitor that this video mode is valid for. Each monitor has
  /// a separate set of valid video modes.
  #[inline]
  pub fn monitor(&self) -> MonitorHandle {
    self.video_mode.monitor()
  }
}

impl std::fmt::Display for VideoMode {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    write!(
      f,
      "{}x{} @ {} Hz ({} bpp)",
      self.size().width,
      self.size().height,
      self.refresh_rate(),
      self.bit_depth()
    )
  }
}

/// Handle to a monitor.
///
/// Allows you to retrieve information about a given monitor and can be used in [`Window`] creation.
///
/// [`Window`]: crate::window::Window
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub struct MonitorHandle {
  pub(crate) inner: platform_impl::MonitorHandle,
}

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

  /// Returns the monitor's resolution.
  #[inline]
  pub fn size(&self) -> PhysicalSize<u32> {
    self.inner.size()
  }

  /// Returns the top-left corner position of the monitor relative to the larger full
  /// screen area.
  #[inline]
  pub fn position(&self) -> PhysicalPosition<i32> {
    self.inner.position()
  }

  /// Returns the scale factor that can be used to map logical pixels to physical pixels, and vice versa.
  ///
  /// See the [`dpi`](crate::dpi) module for more information.
  ///
  /// ## Platform-specific
  ///
  /// - **Android:** Always returns 1.0.
  #[inline]
  pub fn scale_factor(&self) -> f64 {
    self.inner.scale_factor()
  }

  /// Returns all fullscreen video modes supported by this monitor.
  #[inline]
  pub fn video_modes(&self) -> impl Iterator<Item = VideoMode> {
    self.inner.video_modes()
  }
}
