kajam_10/src/main.rs

/// As a dare to myself, I won't use any error-handling crates.

#[derive (Debug)]
enum GameError {
	IoError,
}

impl From <std::io::Error> for GameError {
	fn from (_: std::io::Error) -> Self {
		Self::IoError
	}
}

type Result <T> = std::result::Result <T, GameError>;

/// Prints a string, naively wrapping at 80-character boundaries
/// This means a period might be wrapped separate from the sentence it ends
/// , and frankly I think that's part of the charm.

fn print (mut s: &str) {
	const COLS: usize = 80;
	
	while s.len () > COLS {
		println! ("{}", &s [0..80]);
		s = &s [80..];
	}
	
	println! ("{}", s);
}

fn read_input () -> Result <String> {
	{
		use std::io::Write;
		let mut stdout = std::io::stdout ();
		stdout.write_all (b"> ")?;
		stdout.flush ()?;
	}
	
	let mut buffer = String::new ();
	std::io::stdin ().read_line (&mut buffer)?;
	
	// I don't know why I need the type annotation here, but I do.
	let x: &[_] = &['\r', '\n'];
	let buffer = buffer.trim_end_matches (x).to_string ();
	
	Ok (buffer)
}

fn print_help () -> Response {
	Response::PrintMany (vec! [
		"All commands are ASCII and case-insensitive.",
		"Commands should start with a verb like LOOK.",
		"e.g. `look table`",
		"Single-word verbs are better, e.g. prefer `hint` over `give me a hint`",
		"When in doubt, try generic verbs like `look` or `use` over specific verbs like `actuate`, `type`, or `consolidate`.",
	])
}

fn line_response <S: Into <String>> (line: S) -> Response {
	Response::Print (line.into ())
}

fn undetected_item () -> Response {
	line_response ("That ITEM does not exist in this ROOM, or you have not noticed it.")
}

fn just <T> (t: T) -> Vec <T> {
	vec! [t]
}

#[derive (Debug, PartialEq)]
enum PlayerAction {
	Quit,
	Help,
	Hint,
	Nonsense,
	Wait,
	Look (ItemName),
	LookAround,
	Use (ItemName),
}

#[derive (Clone, Copy, Debug, PartialEq)]
enum ItemName {
	Nonsense,
	
	Door,
	EmergencyExit,
	Keypad,
	Note,
	Table,
}

fn _item_name_display (x: ItemName) -> &'static str {
	match x {
		ItemName::Nonsense => "NONSENSE",
		
		ItemName::Door => "DOOR",
		ItemName::EmergencyExit => "EMERGENCY EXIT",
		ItemName::Keypad => "KEYPAD",
		ItemName::Note => "NOTE",
		ItemName::Table => "TABLE",
	}
}

fn parse_input (s: &str) -> PlayerAction {
	let s = s.to_lowercase ();
	
	if s == "quit" || s == "quit game" {
		return PlayerAction::Quit;
	}
	
	if s == "look" || s == "look around" {
		return PlayerAction::LookAround;
	}
	
	if let Some (rest) = s.strip_prefix ("look at the ") {
		return PlayerAction::Look (parse_item_name (rest));
	}
	
	if let Some (rest) = s.strip_prefix ("look at ") {
		return PlayerAction::Look (parse_item_name (rest));
	}
	
	if let Some (rest) = s.strip_prefix ("look ") {
		return PlayerAction::Look (parse_item_name (rest));
	}
	
	if let Some (rest) = s.strip_prefix ("examine ") {
		return PlayerAction::Look (parse_item_name (rest));
	}
	
	if let Some (rest) = s.strip_prefix ("use the ") {
		return PlayerAction::Use (parse_item_name (rest));
	}
	
	if let Some (rest) = s.strip_prefix ("use ") {
		return PlayerAction::Use (parse_item_name (rest));
	}
	
	if s == "do nothing" {
		return PlayerAction::Wait;
	}
	if s == "wait" {
		return PlayerAction::Wait;
	}
	
	if s == "help" {
		return PlayerAction::Help;
	}
	if s == "hint" {
		return PlayerAction::Hint;
	}
	
	PlayerAction::Nonsense
}

fn parse_item_name (s: &str) -> ItemName {
	if s == "door" {
		return ItemName::Door;
	}
	
	if s == "emergency exit" {
		return ItemName::EmergencyExit;
	}
	
	if s == "keypad" {
		return ItemName::Keypad;
	}
	
	if s == "note" {
		return ItemName::Note;
	}
	
	if s == "table" {
		return ItemName::Table;
	}
	
	ItemName::Nonsense
}

#[derive (Clone, Default)]
struct StateRoom1 {
	detected_keypad: bool,
	detected_note: bool,
}

#[derive (PartialEq)]
enum Response {
	Print (String),
	PrintMany (Vec <&'static str>),
	Sleep (u32),
	Quit,
	JokeEnding,
}

#[derive (Clone, Default)]
struct State {
	room_1: StateRoom1,
}

impl State {
	fn room_1 (&mut self, input: &str) -> Vec <Response> {
		use Response::*;
		
		let action = parse_input (input);
		
		match action {
			PlayerAction::Quit => {
				vec! [
					line_response ("Bye."),
					Quit,
				]
			}
			PlayerAction::Help => {
				just (print_help ())
			},
			PlayerAction::Hint => {
				just (line_response ("Hint for this room: Try using the `help` command."))
			},
			PlayerAction::Nonsense => {
				vec! [
					line_response ("I couldn't understand that. Try `help` or `hint`."),
					line_response ("`hint` may contain spoilers. `help` will not."),
				]
			},
			PlayerAction::Wait => {
				just (line_response ("You wait around a bit. You can hear humming from the electrical lights, and the distant rumble of the building's HVAC system. The room smells faintly of fresh paint. Nothing has changed."))
			},
			PlayerAction::LookAround => {
				let mut output = vec! [
					line_response ("You are in a small room. In one corner is a TABLE. Obvious exits are a DOOR, and an EMERGENCY EXIT."),
				];
				
				if self.room_1.detected_note {
					output.push (line_response ("You have noticed a NOTE on the TABLE."));
				}
				if self.room_1.detected_keypad {
					output.push (line_response ("You have noticed the DOOR is locked by an electronic KEYPAD."));
				}
				
				output
			}
			PlayerAction::Look (item_name) => {
				match item_name {
					ItemName::Door => {
						self.room_1.detected_keypad = true;
						just (line_response ("You examine the DOOR. It is firmly locked, and you don't have any lock-picking tools. On the DOOR is an electronic KEYPAD."))
					},
					ItemName::EmergencyExit => {
						just (line_response ("The EMERGENCY EXIT reads, \"Emergency exit. Push bar to open. Alarm will sound. Door will unlock in 10 seconds.\". The EMERGENCY EXIT is period-accurate for an American Wal-Mart c. 2020 C.E."))
					},
					ItemName::Keypad => {
						if ! self.room_1.detected_keypad {
							return just (undetected_item ());
						}
						
						just (line_response ("The DOOR is locked by an electronic KEYPAD. A soft amber power light indicates that the KEYPAD is likely functional. The KEYPAD buttons are the digits 0-9, Enter, and Clear. Experience tells you that the key code is likely 4 or 5 digits long."))
					},
					ItemName::Note => {
						if ! self.room_1.detected_note {
							return vec! [
								undetected_item (),
							];
						}
						
						just (Response::PrintMany (vec! [
							"You read the NOTE.",
							"",
							"Welcome to SEROTONIN DEPOSITORY.",
							"As you play, keep in mind:",
							"- LOOKing at ITEMS is not always safe",
							"- TAKEing an item may be bad long-term",
							"- WAITing counts as an action",
							"- LOOKing AROUND is always safe",
							"- Other NOTEs may contain non-truths",
							"The code for this first KEYPAD is 1234.",
							"",
							"    -- Phayle Sayf",
							"",
							"You notice that the NOTE is _not_ period-accurate.",
						]))
					},
					ItemName::Table => {
						self.room_1.detected_note = true;
						vec! [
							Response::Print ("You look at the TABLE. Your instincts tell you that it is period-accurate. Upon the TABLE sits a NOTE.".into ()),
						]
					},
					_ => {
						vec! [
							undetected_item (),
						]
					},
				}
			},
			PlayerAction::Use (item_name) => {
				match item_name {
					ItemName::Door => {
						let mut output = vec! [
							line_response ("You can't USE the DOOR, it is locked."),
						];
						
						if ! self.room_1.detected_keypad {
							self.room_1.detected_keypad = true;
							output.push (Response::Print ("You notice an electronic KEYPAD on the DOOR.".into ()));
						}
						
						output
					},
					ItemName::EmergencyExit => {
						vec! [
							Response::Print ("You push on the emergency exit. An alarm starts sounding. Your ADVENTURE GAME ENTHUSIAST friend is going to be very mad at you.".into ()),
							Response::Sleep (5000),
							Response::Print ("The alarm is still sounding. You are getting embarrassed, but you have committed to this path of action.".into ()),
							Response::Sleep (5000),
							Response::Print ("The emergency exit unlocks, and you walk out of the game. Bye.".into ()),
							Response::JokeEnding,
							Response::Quit,
						]
					},
					_ => {
						vec! [
							undetected_item (),
						]
					},
				}
			},
		}
	}
}

fn game () -> Result <()> {
	for line in [
		"Welcome to SEROTONIN DEPOSITORY, the only adventure game ever made.",
		"",
		"You have been consensually kidnapped by a diabolical ADVENTURE GAME ENTHUSIAST and encouraged to solve PUZZLES for their sick PLEASURE. The only winning move is to solve all the PUZZLES.",
		"",
		"Press ENTER if you dare to begin.",
	] {
		print (line);
	}
	
	let input = read_input ()?;
	
	if ! input.is_empty () {
		print ("That was more than just ENTER but OKAY, overachiever.");
	}
	
	print ("");
	
	let mut state = State::default ();
	
	print ("You are in a small room. In one corner is a TABLE.");
	
	'main_loop: loop {
		let input = read_input ()?;
		let responses = state.room_1 (&input);
		
		for response in responses.into_iter () {
			match response {
				Response::Print (line) => print (&line),
				Response::PrintMany (lines) => {
					for line in lines {
						print (line);
					}
				},
				Response::Sleep (x) => std::thread::sleep (std::time::Duration::from_millis (x.into ())),
				Response::Quit => break 'main_loop,
				_ => (),
			}
		}
	}
	
	Ok (())
}

fn main () -> Result <()> {
	game ()?;
	
	Ok (())
}

#[cfg (test)]
mod test {
	#[test]
	fn parse_input () {
		use super::{
			ItemName,
			PlayerAction::*,
		};
		
		for (input, expected) in [
			 ("", Nonsense),
			 ("look at the table", Look (ItemName::Table)),
			 ("look at table", Look (ItemName::Table)),
			 ("look table", Look (ItemName::Table)),
			 ("LOOK TABLE", Look (ItemName::Table)),
			 ("wait", Wait),
			 ("help", Help),
			 ("hint", Hint),
		].into_iter () {
			let actual = super::parse_input (input);
			assert_eq! (actual, expected);
		}
	}
	
	#[test]
	fn joke_ending () {
		use super::{
			Response,
			State,
		};
		
		let mut state = State::default ();
		
		let responses = state.room_1 ("use emergency exit");
		
		assert! (responses.contains (&Response::Quit));
		assert! (responses.contains (&Response::JokeEnding));
	}
}