//! Types for communicating with niri via IPC.
//!
//! After connecting to the niri socket, you can send a single [`Request`] and receive a single
//! [`Reply`], which is a `Result` wrapping a [`Response`]. If you requested an event stream, you
//! can keep reading [`Event`]s from the socket after the response.
//!
//! You can use the [`socket::Socket`] helper if you're fine with blocking communication. However,
//! it is a fairly simple helper, so if you need async, or if you're using a different language,
//! you are encouraged to communicate with the socket manually.
//!
//! 1. Read the socket filesystem path from [`socket::SOCKET_PATH_ENV`] (`$NIRI_SOCKET`).
//! 2. Connect to the socket and write a JSON-formatted [`Request`] on a single line. You can follow
//!    up with a line break and a flush, or just flush and shutdown the write end of the socket.
//! 3. Niri will respond with a single line JSON-formatted [`Reply`].
//! 4. If you requested an event stream, niri will keep responding with JSON-formatted [`Event`]s,
//!    on a single line each.
//!
//! ## Backwards compatibility
//!
//! This crate follows the niri version. It is **not** API-stable in terms of the Rust semver. In
//! particular, expect new struct fields and enum variants to be added in patch version bumps.
#![warn(missing_docs)]

use std::collections::HashMap;
use std::str::FromStr;

use serde::{Deserialize, Serialize};

pub mod socket;
pub mod state;

/// Request from client to niri.
#[derive(Debug, Serialize, Deserialize, Clone)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum Request {
    /// Request the version string for the running niri instance.
    Version,
    /// Request information about connected outputs.
    Outputs,
    /// Request information about workspaces.
    Workspaces,
    /// Request information about open windows.
    Windows,
    /// Request information about the configured keyboard layouts.
    KeyboardLayouts,
    /// Request information about the focused output.
    FocusedOutput,
    /// Request information about the focused window.
    FocusedWindow,
    /// Perform an action.
    Action(Action),
    /// Change output configuration temporarily.
    ///
    /// The configuration is changed temporarily and not saved into the config file. If the output
    /// configuration subsequently changes in the config file, these temporary changes will be
    /// forgotten.
    Output {
        /// Output name.
        output: String,
        /// Configuration to apply.
        action: OutputAction,
    },
    /// Start continuously receiving events from the compositor.
    ///
    /// The compositor should reply with `Reply::Ok(Response::Handled)`, then continuously send
    /// [`Event`]s, one per line.
    ///
    /// The event stream will always give you the full current state up-front. For example, the
    /// first workspace-related event you will receive will be [`Event::WorkspacesChanged`]
    /// containing the full current workspaces state. You *do not* need to separately send
    /// [`Request::Workspaces`] when using the event stream.
    ///
    /// Where reasonable, event stream state updates are atomic, though this is not always the
    /// case. For example, a window may end up with a workspace id for a workspace that had already
    /// been removed. This can happen if the corresponding [`Event::WorkspacesChanged`] arrives
    /// before the corresponding [`Event::WindowOpenedOrChanged`].
    EventStream,
    /// Respond with an error (for testing error handling).
    ReturnError,
}

/// Reply from niri to client.
///
/// Every request gets one reply.
///
/// * If an error had occurred, it will be an `Reply::Err`.
/// * If the request does not need any particular response, it will be
///   `Reply::Ok(Response::Handled)`. Kind of like an `Ok(())`.
/// * Otherwise, it will be `Reply::Ok(response)` with one of the other [`Response`] variants.
pub type Reply = Result<Response, String>;

/// Successful response from niri to client.
#[derive(Debug, Serialize, Deserialize, Clone)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum Response {
    /// A request that does not need a response was handled successfully.
    Handled,
    /// The version string for the running niri instance.
    Version(String),
    /// Information about connected outputs.
    ///
    /// Map from output name to output info.
    Outputs(HashMap<String, Output>),
    /// Information about workspaces.
    Workspaces(Vec<Workspace>),
    /// Information about open windows.
    Windows(Vec<Window>),
    /// Information about the keyboard layout.
    KeyboardLayouts(KeyboardLayouts),
    /// Information about the focused output.
    FocusedOutput(Option<Output>),
    /// Information about the focused window.
    FocusedWindow(Option<Window>),
    /// Output configuration change result.
    OutputConfigChanged(OutputConfigChanged),
}

/// Actions that niri can perform.
// Variants in this enum should match the spelling of the ones in niri-config. Most, but not all,
// variants from niri-config should be present here.
#[derive(Serialize, Deserialize, Debug, Clone)]
#[cfg_attr(feature = "clap", derive(clap::Parser))]
#[cfg_attr(feature = "clap", command(subcommand_value_name = "ACTION"))]
#[cfg_attr(feature = "clap", command(subcommand_help_heading = "Actions"))]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum Action {
    /// Exit niri.
    Quit {
        /// Skip the "Press Enter to confirm" prompt.
        #[cfg_attr(feature = "clap", arg(short, long))]
        skip_confirmation: bool,
    },
    /// Power off all monitors via DPMS.
    PowerOffMonitors {},
    /// Power on all monitors via DPMS.
    PowerOnMonitors {},
    /// Spawn a command.
    Spawn {
        /// Command to spawn.
        #[cfg_attr(feature = "clap", arg(last = true, required = true))]
        command: Vec<String>,
    },
    /// Do a screen transition.
    DoScreenTransition {
        /// Delay in milliseconds for the screen to freeze before starting the transition.
        #[cfg_attr(feature = "clap", arg(short, long))]
        delay_ms: Option<u16>,
    },
    /// Open the screenshot UI.
    Screenshot {},
    /// Screenshot the focused screen.
    ScreenshotScreen {},
    /// Screenshot a window.
    #[cfg_attr(feature = "clap", clap(about = "Screenshot the focused window"))]
    ScreenshotWindow {
        /// Id of the window to screenshot.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        id: Option<u64>,
    },
    /// Close a window.
    #[cfg_attr(feature = "clap", clap(about = "Close the focused window"))]
    CloseWindow {
        /// Id of the window to close.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        id: Option<u64>,
    },
    /// Toggle fullscreen on a window.
    #[cfg_attr(
        feature = "clap",
        clap(about = "Toggle fullscreen on the focused window")
    )]
    FullscreenWindow {
        /// Id of the window to toggle fullscreen of.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        id: Option<u64>,
    },
    /// Focus a window by id.
    FocusWindow {
        /// Id of the window to focus.
        #[cfg_attr(feature = "clap", arg(long))]
        id: u64,
    },
    /// Focus the column to the left.
    FocusColumnLeft {},
    /// Focus the column to the right.
    FocusColumnRight {},
    /// Focus the first column.
    FocusColumnFirst {},
    /// Focus the last column.
    FocusColumnLast {},
    /// Focus the next column to the right, looping if at end.
    FocusColumnRightOrFirst {},
    /// Focus the next column to the left, looping if at start.
    FocusColumnLeftOrLast {},
    /// Focus the window or the monitor above.
    FocusWindowOrMonitorUp {},
    /// Focus the window or the monitor below.
    FocusWindowOrMonitorDown {},
    /// Focus the column or the monitor to the left.
    FocusColumnOrMonitorLeft {},
    /// Focus the column or the monitor to the right.
    FocusColumnOrMonitorRight {},
    /// Focus the window below.
    FocusWindowDown {},
    /// Focus the window above.
    FocusWindowUp {},
    /// Focus the window below or the column to the left.
    FocusWindowDownOrColumnLeft {},
    /// Focus the window below or the column to the right.
    FocusWindowDownOrColumnRight {},
    /// Focus the window above or the column to the left.
    FocusWindowUpOrColumnLeft {},
    /// Focus the window above or the column to the right.
    FocusWindowUpOrColumnRight {},
    /// Focus the window or the workspace above.
    FocusWindowOrWorkspaceDown {},
    /// Focus the window or the workspace above.
    FocusWindowOrWorkspaceUp {},
    /// Move the focused column to the left.
    MoveColumnLeft {},
    /// Move the focused column to the right.
    MoveColumnRight {},
    /// Move the focused column to the start of the workspace.
    MoveColumnToFirst {},
    /// Move the focused column to the end of the workspace.
    MoveColumnToLast {},
    /// Move the focused column to the left or to the monitor to the left.
    MoveColumnLeftOrToMonitorLeft {},
    /// Move the focused column to the right or to the monitor to the right.
    MoveColumnRightOrToMonitorRight {},
    /// Move the focused window down in a column.
    MoveWindowDown {},
    /// Move the focused window up in a column.
    MoveWindowUp {},
    /// Move the focused window down in a column or to the workspace below.
    MoveWindowDownOrToWorkspaceDown {},
    /// Move the focused window up in a column or to the workspace above.
    MoveWindowUpOrToWorkspaceUp {},
    /// Consume or expel a window left.
    #[cfg_attr(
        feature = "clap",
        clap(about = "Consume or expel the focused window left")
    )]
    ConsumeOrExpelWindowLeft {
        /// Id of the window to consume or expel.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        id: Option<u64>,
    },
    /// Consume or expel a window right.
    #[cfg_attr(
        feature = "clap",
        clap(about = "Consume or expel the focused window right")
    )]
    ConsumeOrExpelWindowRight {
        /// Id of the window to consume or expel.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        id: Option<u64>,
    },
    /// Consume the window to the right into the focused column.
    ConsumeWindowIntoColumn {},
    /// Expel the focused window from the column.
    ExpelWindowFromColumn {},
    /// Center the focused column on the screen.
    CenterColumn {},
    /// Focus the workspace below.
    FocusWorkspaceDown {},
    /// Focus the workspace above.
    FocusWorkspaceUp {},
    /// Focus a workspace by reference (index or name).
    FocusWorkspace {
        /// Reference (index or name) of the workspace to focus.
        #[cfg_attr(feature = "clap", arg())]
        reference: WorkspaceReferenceArg,
    },
    /// Focus the previous workspace.
    FocusWorkspacePrevious {},
    /// Move the focused window to the workspace below.
    MoveWindowToWorkspaceDown {},
    /// Move the focused window to the workspace above.
    MoveWindowToWorkspaceUp {},
    /// Move a window to a workspace.
    #[cfg_attr(
        feature = "clap",
        clap(about = "Move the focused window to a workspace by reference (index or name)")
    )]
    MoveWindowToWorkspace {
        /// Id of the window to move.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        window_id: Option<u64>,

        /// Reference (index or name) of the workspace to move the window to.
        #[cfg_attr(feature = "clap", arg())]
        reference: WorkspaceReferenceArg,
    },
    /// Move the focused column to the workspace below.
    MoveColumnToWorkspaceDown {},
    /// Move the focused column to the workspace above.
    MoveColumnToWorkspaceUp {},
    /// Move the focused column to a workspace by reference (index or name).
    MoveColumnToWorkspace {
        /// Reference (index or name) of the workspace to move the column to.
        #[cfg_attr(feature = "clap", arg())]
        reference: WorkspaceReferenceArg,
    },
    /// Move the focused workspace down.
    MoveWorkspaceDown {},
    /// Move the focused workspace up.
    MoveWorkspaceUp {},
    /// Focus the monitor to the left.
    FocusMonitorLeft {},
    /// Focus the monitor to the right.
    FocusMonitorRight {},
    /// Focus the monitor below.
    FocusMonitorDown {},
    /// Focus the monitor above.
    FocusMonitorUp {},
    /// Move the focused window to the monitor to the left.
    MoveWindowToMonitorLeft {},
    /// Move the focused window to the monitor to the right.
    MoveWindowToMonitorRight {},
    /// Move the focused window to the monitor below.
    MoveWindowToMonitorDown {},
    /// Move the focused window to the monitor above.
    MoveWindowToMonitorUp {},
    /// Move the focused column to the monitor to the left.
    MoveColumnToMonitorLeft {},
    /// Move the focused column to the monitor to the right.
    MoveColumnToMonitorRight {},
    /// Move the focused column to the monitor below.
    MoveColumnToMonitorDown {},
    /// Move the focused column to the monitor above.
    MoveColumnToMonitorUp {},
    /// Change the height of a window.
    #[cfg_attr(
        feature = "clap",
        clap(about = "Change the height of the focused window")
    )]
    SetWindowHeight {
        /// Id of the window whose height to set.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        id: Option<u64>,

        /// How to change the height.
        #[cfg_attr(feature = "clap", arg())]
        change: SizeChange,
    },
    /// Reset the height of a window back to automatic.
    #[cfg_attr(
        feature = "clap",
        clap(about = "Reset the height of the focused window back to automatic")
    )]
    ResetWindowHeight {
        /// Id of the window whose height to reset.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        id: Option<u64>,
    },
    /// Switch between preset column widths.
    SwitchPresetColumnWidth {},
    /// Switch between preset window heights.
    SwitchPresetWindowHeight {
        /// Id of the window whose height to switch.
        ///
        /// If `None`, uses the focused window.
        #[cfg_attr(feature = "clap", arg(long))]
        id: Option<u64>,
    },
    /// Toggle the maximized state of the focused column.
    MaximizeColumn {},
    /// Change the width of the focused column.
    SetColumnWidth {
        /// How to change the width.
        #[cfg_attr(feature = "clap", arg())]
        change: SizeChange,
    },
    /// Switch between keyboard layouts.
    SwitchLayout {
        /// Layout to switch to.
        #[cfg_attr(feature = "clap", arg())]
        layout: LayoutSwitchTarget,
    },
    /// Show the hotkey overlay.
    ShowHotkeyOverlay {},
    /// Move the focused workspace to the monitor to the left.
    MoveWorkspaceToMonitorLeft {},
    /// Move the focused workspace to the monitor to the right.
    MoveWorkspaceToMonitorRight {},
    /// Move the focused workspace to the monitor below.
    MoveWorkspaceToMonitorDown {},
    /// Move the focused workspace to the monitor above.
    MoveWorkspaceToMonitorUp {},
    /// Toggle a debug tint on windows.
    ToggleDebugTint {},
    /// Toggle visualization of render element opaque regions.
    DebugToggleOpaqueRegions {},
    /// Toggle visualization of output damage.
    DebugToggleDamage {},
}

/// Change in window or column size.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum SizeChange {
    /// Set the size in logical pixels.
    SetFixed(i32),
    /// Set the size as a proportion of the working area.
    SetProportion(f64),
    /// Add or subtract to the current size in logical pixels.
    AdjustFixed(i32),
    /// Add or subtract to the current size as a proportion of the working area.
    AdjustProportion(f64),
}

/// Workspace reference (id, index or name) to operate on.
#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum WorkspaceReferenceArg {
    /// Id of the workspace.
    Id(u64),
    /// Index of the workspace.
    Index(u8),
    /// Name of the workspace.
    Name(String),
}

/// Layout to switch to.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum LayoutSwitchTarget {
    /// The next configured layout.
    Next,
    /// The previous configured layout.
    Prev,
}

/// Output actions that niri can perform.
// Variants in this enum should match the spelling of the ones in niri-config. Most thigs from
// niri-config should be present here.
#[derive(Serialize, Deserialize, Debug, Clone)]
#[cfg_attr(feature = "clap", derive(clap::Parser))]
#[cfg_attr(feature = "clap", command(subcommand_value_name = "ACTION"))]
#[cfg_attr(feature = "clap", command(subcommand_help_heading = "Actions"))]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum OutputAction {
    /// Turn off the output.
    Off,
    /// Turn on the output.
    On,
    /// Set the output mode.
    Mode {
        /// Mode to set, or "auto" for automatic selection.
        ///
        /// Run `niri msg outputs` to see the available modes.
        #[cfg_attr(feature = "clap", arg())]
        mode: ModeToSet,
    },
    /// Set the output scale.
    Scale {
        /// Scale factor to set, or "auto" for automatic selection.
        #[cfg_attr(feature = "clap", arg())]
        scale: ScaleToSet,
    },
    /// Set the output transform.
    Transform {
        /// Transform to set, counter-clockwise.
        #[cfg_attr(feature = "clap", arg())]
        transform: Transform,
    },
    /// Set the output position.
    Position {
        /// Position to set, or "auto" for automatic selection.
        #[cfg_attr(feature = "clap", command(subcommand))]
        position: PositionToSet,
    },
    /// Set the variable refresh rate mode.
    Vrr {
        /// Variable refresh rate mode to set.
        #[cfg_attr(feature = "clap", command(flatten))]
        vrr: VrrToSet,
    },
}

/// Output mode to set.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum ModeToSet {
    /// Niri will pick the mode automatically.
    Automatic,
    /// Specific mode.
    Specific(ConfiguredMode),
}

/// Output mode as set in the config file.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct ConfiguredMode {
    /// Width in physical pixels.
    pub width: u16,
    /// Height in physical pixels.
    pub height: u16,
    /// Refresh rate.
    pub refresh: Option<f64>,
}

/// Output scale to set.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum ScaleToSet {
    /// Niri will pick the scale automatically.
    Automatic,
    /// Specific scale.
    Specific(f64),
}

/// Output position to set.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "clap", derive(clap::Subcommand))]
#[cfg_attr(feature = "clap", command(subcommand_value_name = "POSITION"))]
#[cfg_attr(feature = "clap", command(subcommand_help_heading = "Position Values"))]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum PositionToSet {
    /// Position the output automatically.
    #[cfg_attr(feature = "clap", command(name = "auto"))]
    Automatic,
    /// Set a specific position.
    #[cfg_attr(feature = "clap", command(name = "set"))]
    Specific(ConfiguredPosition),
}

/// Output position as set in the config file.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "clap", derive(clap::Args))]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct ConfiguredPosition {
    /// Logical X position.
    pub x: i32,
    /// Logical Y position.
    pub y: i32,
}

/// Output VRR to set.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "clap", derive(clap::Args))]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct VrrToSet {
    /// Whether to enable variable refresh rate.
    #[cfg_attr(
        feature = "clap",
        arg(
            value_name = "ON|OFF",
            action = clap::ArgAction::Set,
            value_parser = clap::builder::BoolishValueParser::new(),
            hide_possible_values = true,
        ),
    )]
    pub vrr: bool,
    /// Only enable when the output shows a window matching the variable-refresh-rate window rule.
    #[cfg_attr(feature = "clap", arg(long))]
    pub on_demand: bool,
}

/// Connected output.
#[derive(Debug, Serialize, Deserialize, Clone)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct Output {
    /// Name of the output.
    pub name: String,
    /// Textual description of the manufacturer.
    pub make: String,
    /// Textual description of the model.
    pub model: String,
    /// Serial of the output, if known.
    pub serial: Option<String>,
    /// Physical width and height of the output in millimeters, if known.
    pub physical_size: Option<(u32, u32)>,
    /// Available modes for the output.
    pub modes: Vec<Mode>,
    /// Index of the current mode in [`Self::modes`].
    ///
    /// `None` if the output is disabled.
    pub current_mode: Option<usize>,
    /// Whether the output supports variable refresh rate.
    pub vrr_supported: bool,
    /// Whether variable refresh rate is enabled on the output.
    pub vrr_enabled: bool,
    /// Logical output information.
    ///
    /// `None` if the output is not mapped to any logical output (for example, if it is disabled).
    pub logical: Option<LogicalOutput>,
}

/// Output mode.
#[derive(Debug, Serialize, Deserialize, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct Mode {
    /// Width in physical pixels.
    pub width: u16,
    /// Height in physical pixels.
    pub height: u16,
    /// Refresh rate in millihertz.
    pub refresh_rate: u32,
    /// Whether this mode is preferred by the monitor.
    pub is_preferred: bool,
}

/// Logical output in the compositor's coordinate space.
#[derive(Debug, Serialize, Deserialize, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct LogicalOutput {
    /// Logical X position.
    pub x: i32,
    /// Logical Y position.
    pub y: i32,
    /// Width in logical pixels.
    pub width: u32,
    /// Height in logical pixels.
    pub height: u32,
    /// Scale factor.
    pub scale: f64,
    /// Transform.
    pub transform: Transform,
}

/// Output transform, which goes counter-clockwise.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq)]
#[cfg_attr(feature = "clap", derive(clap::ValueEnum))]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum Transform {
    /// Untransformed.
    Normal,
    /// Rotated by 90°.
    #[serde(rename = "90")]
    _90,
    /// Rotated by 180°.
    #[serde(rename = "180")]
    _180,
    /// Rotated by 270°.
    #[serde(rename = "270")]
    _270,
    /// Flipped horizontally.
    Flipped,
    /// Rotated by 90° and flipped horizontally.
    #[cfg_attr(feature = "clap", value(name("flipped-90")))]
    Flipped90,
    /// Flipped vertically.
    #[cfg_attr(feature = "clap", value(name("flipped-180")))]
    Flipped180,
    /// Rotated by 270° and flipped horizontally.
    #[cfg_attr(feature = "clap", value(name("flipped-270")))]
    Flipped270,
}

/// Toplevel window.
#[derive(Serialize, Deserialize, Debug, Clone)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct Window {
    /// Unique id of this window.
    ///
    /// This id remains constant while this window is open.
    ///
    /// Do not assume that window ids will always increase without wrapping, or start at 1. That is
    /// an implementation detail subject to change. For example, ids may change to be randomly
    /// generated for each new window.
    pub id: u64,
    /// Title, if set.
    pub title: Option<String>,
    /// Application ID, if set.
    pub app_id: Option<String>,
    /// Id of the workspace this window is on, if any.
    pub workspace_id: Option<u64>,
    /// Whether this window is currently focused.
    ///
    /// There can be either one focused window or zero (e.g. when a layer-shell surface has focus).
    pub is_focused: bool,
}

/// Output configuration change result.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum OutputConfigChanged {
    /// The target output was connected and the change was applied.
    Applied,
    /// The target output was not found, the change will be applied when it is connected.
    OutputWasMissing,
}

/// A workspace.
#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct Workspace {
    /// Unique id of this workspace.
    ///
    /// This id remains constant regardless of the workspace moving around and across monitors.
    ///
    /// Do not assume that workspace ids will always increase without wrapping, or start at 1. That
    /// is an implementation detail subject to change. For example, ids may change to be randomly
    /// generated for each new workspace.
    pub id: u64,
    /// Index of the workspace on its monitor.
    ///
    /// This is the same index you can use for requests like `niri msg action focus-workspace`.
    ///
    /// This index *will change* as you move and re-order workspace. It is merely the workspace's
    /// current position on its monitor. Workspaces on different monitors can have the same index.
    ///
    /// If you need a unique workspace id that doesn't change, see [`Self::id`].
    pub idx: u8,
    /// Optional name of the workspace.
    pub name: Option<String>,
    /// Name of the output that the workspace is on.
    ///
    /// Can be `None` if no outputs are currently connected.
    pub output: Option<String>,
    /// Whether the workspace is currently active on its output.
    ///
    /// Every output has one active workspace, the one that is currently visible on that output.
    pub is_active: bool,
    /// Whether the workspace is currently focused.
    ///
    /// There's only one focused workspace across all outputs.
    pub is_focused: bool,
    /// Id of the active window on this workspace, if any.
    pub active_window_id: Option<u64>,
}

/// Configured keyboard layouts.
#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub struct KeyboardLayouts {
    /// XKB names of the configured layouts.
    pub names: Vec<String>,
    /// Index of the currently active layout in `names`.
    pub current_idx: u8,
}

/// A compositor event.
#[derive(Serialize, Deserialize, Debug, Clone)]
#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))]
pub enum Event {
    /// The workspace configuration has changed.
    WorkspacesChanged {
        /// The new workspace configuration.
        ///
        /// This configuration completely replaces the previous configuration. I.e. if any
        /// workspaces are missing from here, then they were deleted.
        workspaces: Vec<Workspace>,
    },
    /// A workspace was activated on an output.
    ///
    /// This doesn't always mean the workspace became focused, just that it's now the active
    /// workspace on its output. All other workspaces on the same output become inactive.
    WorkspaceActivated {
        /// Id of the newly active workspace.
        id: u64,
        /// Whether this workspace also became focused.
        ///
        /// If `true`, this is now the single focused workspace. All other workspaces are no longer
        /// focused, but they may remain active on their respective outputs.
        focused: bool,
    },
    /// An active window changed on a workspace.
    WorkspaceActiveWindowChanged {
        /// Id of the workspace on which the active window changed.
        workspace_id: u64,
        /// Id of the new active window, if any.
        active_window_id: Option<u64>,
    },
    /// The window configuration has changed.
    WindowsChanged {
        /// The new window configuration.
        ///
        /// This configuration completely replaces the previous configuration. I.e. if any windows
        /// are missing from here, then they were closed.
        windows: Vec<Window>,
    },
    /// A new toplevel window was opened, or an existing toplevel window changed.
    WindowOpenedOrChanged {
        /// The new or updated window.
        ///
        /// If the window is focused, all other windows are no longer focused.
        window: Window,
    },
    /// A toplevel window was closed.
    WindowClosed {
        /// Id of the removed window.
        id: u64,
    },
    /// Window focus changed.
    ///
    /// All other windows are no longer focused.
    WindowFocusChanged {
        /// Id of the newly focused window, or `None` if no window is now focused.
        id: Option<u64>,
    },
    /// The configured keyboard layouts have changed.
    KeyboardLayoutsChanged {
        /// The new keyboard layout configuration.
        keyboard_layouts: KeyboardLayouts,
    },
    /// The keyboard layout switched.
    KeyboardLayoutSwitched {
        /// Index of the newly active layout.
        idx: u8,
    },
}

impl FromStr for WorkspaceReferenceArg {
    type Err = &'static str;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let reference = if let Ok(index) = s.parse::<i32>() {
            if let Ok(idx) = u8::try_from(index) {
                Self::Index(idx)
            } else {
                return Err("workspace index must be between 0 and 255");
            }
        } else {
            Self::Name(s.to_string())
        };

        Ok(reference)
    }
}

impl FromStr for SizeChange {
    type Err = &'static str;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.split_once('%') {
            Some((value, empty)) => {
                if !empty.is_empty() {
                    return Err("trailing characters after '%' are not allowed");
                }

                match value.bytes().next() {
                    Some(b'-' | b'+') => {
                        let value = value.parse().map_err(|_| "error parsing value")?;
                        Ok(Self::AdjustProportion(value))
                    }
                    Some(_) => {
                        let value = value.parse().map_err(|_| "error parsing value")?;
                        Ok(Self::SetProportion(value))
                    }
                    None => Err("value is missing"),
                }
            }
            None => {
                let value = s;
                match value.bytes().next() {
                    Some(b'-' | b'+') => {
                        let value = value.parse().map_err(|_| "error parsing value")?;
                        Ok(Self::AdjustFixed(value))
                    }
                    Some(_) => {
                        let value = value.parse().map_err(|_| "error parsing value")?;
                        Ok(Self::SetFixed(value))
                    }
                    None => Err("value is missing"),
                }
            }
        }
    }
}

impl FromStr for LayoutSwitchTarget {
    type Err = &'static str;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "next" => Ok(Self::Next),
            "prev" => Ok(Self::Prev),
            _ => Err(r#"invalid layout action, can be "next" or "prev""#),
        }
    }
}

impl FromStr for Transform {
    type Err = &'static str;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "normal" => Ok(Self::Normal),
            "90" => Ok(Self::_90),
            "180" => Ok(Self::_180),
            "270" => Ok(Self::_270),
            "flipped" => Ok(Self::Flipped),
            "flipped-90" => Ok(Self::Flipped90),
            "flipped-180" => Ok(Self::Flipped180),
            "flipped-270" => Ok(Self::Flipped270),
            _ => Err(concat!(
                r#"invalid transform, can be "90", "180", "270", "#,
                r#""flipped", "flipped-90", "flipped-180" or "flipped-270""#
            )),
        }
    }
}

impl FromStr for ModeToSet {
    type Err = &'static str;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if s.eq_ignore_ascii_case("auto") {
            return Ok(Self::Automatic);
        }

        let mode = s.parse()?;
        Ok(Self::Specific(mode))
    }
}

impl FromStr for ConfiguredMode {
    type Err = &'static str;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let Some((width, rest)) = s.split_once('x') else {
            return Err("no 'x' separator found");
        };

        let (height, refresh) = match rest.split_once('@') {
            Some((height, refresh)) => (height, Some(refresh)),
            None => (rest, None),
        };

        let width = width.parse().map_err(|_| "error parsing width")?;
        let height = height.parse().map_err(|_| "error parsing height")?;
        let refresh = refresh
            .map(str::parse)
            .transpose()
            .map_err(|_| "error parsing refresh rate")?;

        Ok(Self {
            width,
            height,
            refresh,
        })
    }
}

impl FromStr for ScaleToSet {
    type Err = &'static str;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if s.eq_ignore_ascii_case("auto") {
            return Ok(Self::Automatic);
        }

        let scale = s.parse().map_err(|_| "error parsing scale")?;
        Ok(Self::Specific(scale))
    }
}