//! Types for communicating with niri via IPC.
#![warn(missing_docs)]

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

use serde::{Deserialize, Serialize};

/// Name of the environment variable containing the niri IPC socket path.
pub const SOCKET_PATH_ENV: &str = "NIRI_SOCKET";

/// Request from client to niri.
#[derive(Debug, Serialize, Deserialize, Clone)]
pub enum Request {
    /// Request information about connected outputs.
    Outputs,
    /// Perform an action.
    Action(Action),
}

/// 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)]
pub enum Response {
    /// A request that does not need a response was handled successfully.
    Handled,
    /// Information about connected outputs.
    ///
    /// Map from connector name to output info.
    Outputs(HashMap<String, Output>),
}

/// 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"))]
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,
    /// Spawn a command.
    Spawn {
        /// Command to spawn.
        #[cfg_attr(feature = "clap", arg(last = true, required = true))]
        command: Vec<String>,
    },
    /// Open the screenshot UI.
    Screenshot,
    /// Screenshot the focused screen.
    ScreenshotScreen,
    /// Screenshot the focused window.
    ScreenshotWindow,
    /// Close the focused window.
    CloseWindow,
    /// Toggle fullscreen on the focused window.
    FullscreenWindow,
    /// 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 window below.
    FocusWindowDown,
    /// Focus the window above.
    FocusWindowUp,
    /// 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 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 the focused window left.
    ConsumeOrExpelWindowLeft,
    /// Consume or expel the focused window right.
    ConsumeOrExpelWindowRight,
    /// 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 index.
    FocusWorkspace {
        /// Index of the workspace to focus.
        #[cfg_attr(feature = "clap", arg())]
        index: u8,
    },
    /// Move the focused window to the workspace below.
    MoveWindowToWorkspaceDown,
    /// Move the focused window to the workspace above.
    MoveWindowToWorkspaceUp,
    /// Move the focused window to a workspace by index.
    MoveWindowToWorkspace {
        /// Index of the target workspace.
        #[cfg_attr(feature = "clap", arg())]
        index: u8,
    },
    /// 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 index.
    MoveColumnToWorkspace {
        /// Index of the target workspace.
        #[cfg_attr(feature = "clap", arg())]
        index: u8,
    },
    /// 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 the focused window.
    SetWindowHeight {
        /// How to change the height.
        #[cfg_attr(feature = "clap", arg())]
        change: SizeChange,
    },
    /// Switch between preset column widths.
    SwitchPresetColumnWidth,
    /// 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,
}

/// Change in window or column size.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq)]
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),
}

/// Layout to switch to.
#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq)]
pub enum LayoutSwitchTarget {
    /// The next configured layout.
    Next,
    /// The previous configured layout.
    Prev,
}

/// Connected output.
#[derive(Debug, Serialize, Deserialize, Clone)]
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,
    /// 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>,
}

/// Output mode.
#[derive(Debug, Serialize, Deserialize, Clone, Copy)]
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,
}

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""#),
        }
    }
}