3 files changed, 199 insertions, 0 deletions
diff --git a/src/cli/cmd/mod.rs b/src/cli/cmd/mod.rs
new file mode 100644
index 0000000..29063e8
--- /dev/null
+++ b/src/cli/cmd/mod.rs
@@ -0,0 +1,53 @@
+//! The commands that can be performed in the CLI
+
+pub mod save;
+
+pub use save::*;
+
+use crate::Editor;
+use std::ops::RangeInclusive;
+
+/// Errors that can occur when parsing a command. This is for syntax checking, the
+/// semantics are checked when trying to execute the command.
+#[allow(missing_docs)]
+#[derive(thiserror::Error, Debug)]
+pub enum CmdParseError {
+    #[error("no command specified")]
+    StringEmpty,
+    #[error("the command {0} is unknown")]
+    NoSuchCmd(String),
+    #[error("wrong number of arguments. Expected in range {1:?}, but received {0}")]
+    WrongNumberOfArgs(usize, RangeInclusive<usize>),
+    #[error("{0} cannot be converted into a {1}, which is required")]
+    InvalidArgType(String, &'static str),
+}
+
+/// Attempts to parse a command from the given string. If it is unsuccessful, it returns a
+/// [CmdParseError].
+pub fn parse_command(string: &str) -> Result<Box<dyn Command>, CmdParseError> {
+    if string.is_empty() {
+        return Err(CmdParseError::StringEmpty);
+    }
+
+    let parts: Vec<&str> = string.split_whitespace().collect();
+    match parts[0] {
+        "w" => Ok(Box::new(Save::from_args(&parts[1..])?)),
+        other => Err(CmdParseError::NoSuchCmd(other.to_owned())),
+    }
+}
+
+/// Indicates that this entity (command) can be created from arguments. Make sure to check what is
+/// expected, to pass the arguments to the correct command.
+pub trait FromArgs: Sized {
+    /// Creates a new instance from the arguments provided. If for whatever reason the syntax of the
+    /// given arguments is correct an [ArgParseError] is returned.
+    fn from_args(args: &[&str]) -> Result<Self, CmdParseError>;
+}
+
+/// A common trait for all commands.
+pub trait Command {
+    /// Process this command on the provided context. Returns either a string with the output of the
+    /// command when everything went right with it, or an error string explaining what went wrong,
+    /// which can be displayed to the user.
+    fn process(&self, editor: &mut Editor) -> Result<String, String>;
+}
diff --git a/src/cli/cmd/save.rs b/src/cli/cmd/save.rs
new file mode 100644
index 0000000..2c022cf
--- /dev/null
+++ b/src/cli/cmd/save.rs
@@ -0,0 +1,42 @@
+//! Save the contents of the map to disk
+
+use super::Command;
+use super::{CmdParseError, FromArgs};
+use crate::map::MapData;
+use crate::Editor;
+use std::path::PathBuf;
+
+/// The save command can take any destination in the filesystem the user can write to. Processing
+/// will then save the map contents to that destination, overwriting anything that may be there.
+pub struct Save {
+    destination: PathBuf,
+}
+
+impl FromArgs for Save {
+    fn from_args(args: &[&str]) -> Result<Self, CmdParseError> {
+        if args.len() != 1 {
+            return Err(CmdParseError::WrongNumberOfArgs(args.len(), 1..=1));
+        }
+
+        Ok(Self {
+            destination: PathBuf::from(args[0]),
+        })
+    }
+}
+
+impl Command for Save {
+    fn process(&self, editor: &mut Editor) -> Result<String, String> {
+        let data = MapData::extract_data(editor.map());
+
+        match data.write_to_file(&self.destination) {
+            Ok(_) => Ok(format!(
+                "Successfully wrote contents to `{:?}`",
+                &self.destination
+            )),
+            Err(e) => Err(format!(
+                "Unable to write to `{:?}`. Error: {:?}",
+                &self.destination, e
+            )),
+        }
+    }
+}
diff --git a/src/cli/mod.rs b/src/cli/mod.rs
new file mode 100644
index 0000000..e96070f
--- /dev/null
+++ b/src/cli/mod.rs
@@ -0,0 +1,104 @@
+//! In-window Command line interface. Used for operations that are just easier than with GUI.
+//!
+//! Sometimes it is nice to have a GUI, for instance when a selection has to be made, things have to
+//! be moved etc., however for operations like saving/loading and exporting, no such thing has to be
+//! done and the GUI is really just slowing you down (at least in my opinion). For these operations,
+//! it is much better to simply have a command do that specific thing. It is also much easier to
+//! implement a new command, so features can be tested more quickly. For some things, there should
+//! still be a GUI option. With the example of saving/loading, it is much easier to find some hidden
+//! folder in a GUI, so that is definitely a consideration for the future.
+
+pub mod cmd;
+pub use self::cmd::*;
+
+use crate::colours::DEFAULT_COLOURS;
+use crate::math::Vec2;
+use crate::Editor;
+use raylib::drawing::{RaylibDraw, RaylibDrawHandle};
+use raylib::ffi::KeyboardKey;
+use raylib::RaylibHandle;
+
+/// The command line interface. Should be created only once per program instance.
+pub struct CLI {
+    text: String,
+    active: bool,
+}
+
+impl CLI {
+    /// Create a CLI for this instance
+    pub fn new() -> Self {
+        Self {
+            text: String::new(),
+            active: false,
+        }
+    }
+
+    /// Activates the CLI, which will now capture keyboard input and execute commands accordingly.
+    pub fn activate(&mut self) {
+        if !self.active {
+            self.text = ";".to_owned();
+            self.active = true;
+        }
+    }
+
+    /// Handle input for the command line and perform any commands the user may want to run.
+    pub fn update(&mut self, rl: &mut RaylibHandle, editor: &mut Editor) {
+        /* Check if the CLI is currently active. If not and it should not be activated according to
+         * keyboard input, there is nothing to do.
+         */
+        if !self.active {
+            if rl.is_key_pressed(KeyboardKey::KEY_SEMICOLON) {
+                // Don't write the keypress again.
+                rl.get_key_pressed();
+                self.activate();
+            } else {
+                return;
+            }
+        }
+
+        // The CLI is currently active. Handle input to it.
+        if let Some(key) = rl.get_key_pressed_number() {
+            self.text.push(key as u8 as char);
+        } else if rl.is_key_pressed(KeyboardKey::KEY_BACKSPACE) {
+            self.text.pop();
+        } else if rl.is_key_pressed(KeyboardKey::KEY_ESCAPE) {
+            self.text.clear();
+        }
+
+        // When the text is empty, there is also no command marker, so set as inactive and leave.
+        if self.text.is_empty() {
+            self.active = false;
+            return;
+        }
+
+        // Perform the entered command, when the enter-key is pressed.
+        if rl.is_key_pressed(KeyboardKey::KEY_ENTER) {
+            self.active = false;
+            match cmd::parse_command(&self.text[1..]) {
+                Ok(cmd) => match cmd.process(editor) {
+                    Ok(res) => self.text = format!("SUCCESS: {}", res),
+                    Err(err) => self.text = format!("ERROR: {}", err),
+                },
+                Err(err) => self.text = format!("SYNTAX ERROR: {}", err),
+            }
+        }
+    }
+
+    /// Draw the command line at the bottom of the window.
+    pub fn draw(&self, rld: &mut RaylibDrawHandle) {
+        let pos = Vec2::new(150., rld.get_screen_height() as f32 - 25.);
+
+        rld.draw_rectangle_v(
+            pos,
+            Vec2::new(rld.get_screen_width() as f32 - pos.x, 25.),
+            DEFAULT_COLOURS.cli_background,
+        );
+        rld.draw_text(
+            &self.text,
+            155,
+            rld.get_screen_height() - 22,
+            20,
+            DEFAULT_COLOURS.cli_foreground,
+        );
+    }
+}