/*! Color [`Palette`] and [`Tags`]

# Customization

The color [`Palette`] and decorative [`Tags`] used by the [`Conciliator`] can be customized at compile-time through environment variables. `CONCILIATOR_PALETTE` and `CONCILIATOR_TAGS` will be parsed by `const` functions to determine the default palette and tags.

## Custom Palette

The `CONCILIATOR_PALETTE` environment variable can be set to override the default [`Palette`].
It should contain the names of all 8 [`ColorCode`]s you want to use, separated by a comma and a space (`, `).
The order is the same as the fields in the [`Palette`] struct: the color of the `[ ]` brackets, then Alpha, Beta, Gamma, Delta, Zeta, Iota and Omega.

Note that the capitalization has to match the [`ColorCode`] exactly: `IntenseBlue` & `Red` will work, `intenseblue`, `intense_blue`, `red`, `RED` and so on will not.
Alternatively, you can use the numeric representation of the [`ColorCode`], which is an integer from 0 to 15 (inclusive).
See the [`ColorCode`] documentation for a table of all colors and their associated numbers.

```toml
[env]
# default color palette
CONCILIATOR_PALETTE = "White, Blue, Green, Red, IntenseRed, Yellow, Cyan, IntenseBlack";
# same color palette using numeric representation
CONCILIATOR_PALETTE = "7, 4, 2, 1, 9, 3, 6, 8";
```

## Custom Tags

As described in the [`Conciliator`] docs, the **`[ > ]`** tags are purely decorative.
Additionally, glyphs may look completely different depending on the terminal font that is used, or may not be available at all.
Because of this, and because everyone has different tastes, the characters / strings that are used can be customized.

By default, the [`Tags`] use only basic characters (`>`, `+` and letters) that should be available in all terminal fonts.
This is a very conservative choice for maximum compatibility out-of-the-box, which you are welcome to override by setting the `CONCILIATOR_TAGS` environment variable at compile-time.

The `CONCILIATOR_TAGS` environment variable needs to contain all the tags (status, info, warn & error) in comma-separated (`, `) square brackets (`[ … ]`).
Additionally, it needs to begin with `[ Tags ], ` like in the two examples given below.

```toml
[env]
# default tags, should be compatible with all terminal fonts
CONCILIATOR_TAGS = "[ Tags ], [ > ], [ + ], [ WARN ], [ ERROR ]"
# prettier status & info tags using glyphs that may not be available
CONCILIATOR_TAGS = "[ Tags ], [ ➤ ], [ → ], [ WARN ], [ ERROR ]"
```

## Environment Variables

There are many ways to set these environment variable during your build, but the recommended way is to use the `[env]` section of [`.cargo/config.toml`](https://doc.rust-lang.org/cargo/reference/config.html) configuration files for Cargo.

As you can read in the [Cargo book], this offers a lot of flexibility: you can place these configuration files in the crate, workspace, or even under the home directory.
Unfortunately, the precedence of these files is not quite what we would want here, since the user's personal configuration in their home directory gets overruled by anything set at the crate and workspace level.

On top of that, Cargo might fail to recompile the dependency when you change the environment variables (possibly related to [cargo#13280]).
If this happens to you, you can run `cargo clean -p conciliator` in your crate/workspace directory to force it to recompile the dependency in the next `cargo build`.

Please note that there are currently no error messages if the `CONCILIATOR_TAGS` or `CONCILIATOR_PALETTE` strings are invalid.
If the tags or palette can't be parsed, it will just silently fall back to the default.
Finally, remember that the environment variables will only be read and parsed at **compile-time**.

[Cargo book]: https://doc.rust-lang.org/cargo/reference/config.html
[cargo#13280]: https://github.com/rust-lang/cargo/issues/13280
*/

use std::fmt::{
	self,
	Display
};
use std::io::Write;
use std::mem::{
	needs_drop,
	size_of
};
use std::str::from_utf8;

use crate::{
	Conciliator,
	Buffer,
	Print
};
use crate::data::tree;
use crate::term::{
	ColorCode,
	EmitEscapes
};

const CUSTOM_PACKED_TAGS: Option<&str> = option_env!("CONCILIATOR_TAGS");
const DEFAULT_TAGS: Tags = Tags {
	status: ">",
	info: "+",
	warn: "WARN",
	error: "ERROR"
};
const CUSTOM_PACKED_PALETTE: Option<&str> = option_env!("CONCILIATOR_PALETTE");
const DEFAULT_PALETTE: Palette = Palette {
	tag: ColorCode::White,

	alpha: ColorCode::Blue,
	beta: ColorCode::Green,
	gamma: ColorCode::Red,
	delta: ColorCode::IntenseRed,

	zeta: ColorCode::Yellow,
	iota: ColorCode::Cyan,

	omega: ColorCode::IntenseBlack
};

static mut PALETTE: Palette = match Palette::unpack(CUSTOM_PACKED_PALETTE) {
	Some(custom_palette) => custom_palette,
	None => DEFAULT_PALETTE
};

pub(crate) static TAGS: Tags = match Tags::unpack(CUSTOM_PACKED_TAGS) {
	Some(custom_tags) => custom_tags,
	None => DEFAULT_TAGS
};

/// Provides a simplified and unified set of [`ColorCode`]s, i.e. a *color palette*
///
/// It simplifies the use of a small and consistent color palette across the entire application (or even many different applications).
/// Additionally, it becomes possible to swap out the entire color palette to suit the users tastes and terminal color scheme.
///
/// Currently implemented (subject to change) using a `static PALETTE` which can be read using [`Color::get_from_static`].
#[derive(Clone, Copy, Eq, PartialEq)]
pub struct Palette {
	/// Color of the tag brackets `[ ]`
	pub tag: ColorCode,

	/// Color of the `status` tag symbol
	pub alpha: ColorCode,
	/// Color of the `info` tag symbol
	pub beta: ColorCode,
	/// Color of the `warn` tag symbol
	pub gamma: ColorCode,
	/// Color of the `error` tag symbol
	pub delta: ColorCode,

	/// Spare color
	pub zeta: ColorCode,
	/// Spare color
	pub iota: ColorCode,

	/// Color of the tree branches
	pub omega: ColorCode
}

/// Stores the strings used as tags by the [`Conciliator`]
pub struct Tags {
	/// Tag for general status messages, default: `>`
	pub status: &'static str,
	/// Tag for general information messages, default: `+`
	pub info: &'static str,
	/// Tag for warning messages, default: `WARN`
	pub warn: &'static str,
	/// Tag for error messages, default: `ERROR`
	pub error: &'static str
}

/// Color in the color [`Palette`]
///
/// The variants are not named after any (actual) colors, since these come from the [`Palette`] and may be changed.
/// Nonetheless, it is intended that the variants specify some meaning / intention about the *actual colors* they will be resolved to and, importantly, the role and visual impact they have *in relation to* the color scheme as a whole.
///
/// Currently these semantics are not very fleshed out, except to say that:
///    - `Alpha` and `Beta` are used for the most common [`Tags`], which makes them the most generally suitable
///    - `Gamma` and `Delta` are used for warnings and errors respectively and should therefore only be used sparingly
///    - `Zeta` and `Iota` are ill-defined, but perhaps they can be considered niche versions of `Alpha` and `Beta`
///    - `Omega` is used for various decorations and is a color with *low visual impact*, specifically that it is less prominent (i.e. closer to the background color) than plain/normal text.
///
/// There are some implications for the amount of contrast between pairs of colors (perhaps `Gamma` and `Delta` should be fairly similar colors), but this needs to be refined.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum Color {
	/// Used for the [status](Tags::status) tag, generally suitable
	Alpha,
	/// Used for the [info](Tags::info) tag, generally suitable
	Beta,
	/// Used for the [warn](Tags::warn) tag, use sparingly
	Gamma,
	/// Used for the [error](Tags::error) tag, use sparingly
	Delta,
	/// Spare color
	Zeta,
	/// Spare color
	Iota,
	/// Low intensity color
	Omega
}

/// Retrieve the current global `static` color [`Palette`]
///
/// This returns a copy of the global `static` as it is at that time.
pub fn get_palette() -> Palette {
	unsafe {PALETTE}
}
/// Overwrite the global `static` color [`Palette`]
///
/// # Safety
///
/// In a multi-threaded context this is technically undefined behavior, because another thread might be reading from (or writing to) it at the same time.
/// Still, there's nothing to go (catastrophically) wrong: the [`Palette`] is simply being overwritten in-place -- even if another read or write was interleaved with this, there's no way an invalid [`ColorCode`] could be produced since each of them fits into a single byte.
///
/// It is, however, plausible that overlapping reads and writes produce a novel combination of [`ColorCode`]s that is a mash-up of (the) old and new [`Palette`]s.
/// This may be undesired, but it shouldn't violate memory safety.
///
/// With all that said, it is completely fine to call this function in a single-threaded application.
/// Ideally, it would be called once, at the beginning, before calling [`conciliator::init`](crate::init).
pub unsafe fn set_palette(new: Palette) {
	assert!(!needs_drop::<Palette>());
	assert!(size_of::<ColorCode>() == 1);
	assert!(size_of::<Palette>() == 8);

	// both compile to `mov qword ptr …`, might be different on 32bit
	//std::ptr::write(&mut PALETTE, new);
	PALETTE = new;
}

/// Extends [`EmitEscapes`] to easily *push* (colored) text onto a buffer
///
/// The `push*` methods take and return `&mut Self` to enable method chaining:
/// ```
/// # let con = conciliator::init();
/// # use conciliator::Conciliator;
/// use conciliator::Paint;
/// let mut buffer = con.status(..);
/// buffer.push_beta("Hello")
///     .push_plain(" ")
///     .push_alpha_bold("World")
///     .push_bold("!");
/// ```
/// Additionally this trait provides a method for adding a [`tag`](Self::tag) to the buffer, used by the [`Conciliator`].
pub trait Paint: EmitEscapes {
	/// Add a tag to this buffer: `[ $tag ] `
	fn tag(&mut self, color: Color, tag: &str) -> &mut Self {
		let tag_color = unsafe {PALETTE.tag};
		self.set_bold().unwrap();

		self.set_color(tag_color).unwrap();
		write!(self, "[ ").unwrap();

		self.set_color(color.get_from_static()).unwrap();
		self.write_all(tag.as_bytes()).unwrap();

		self.set_color(tag_color).unwrap();
		write!(self, " ] ").unwrap();

		self.reset().unwrap();
		self
	}

	/// Append `thing` onto the buffer using the [`Display`] trait (plain uncolored text)
	fn push_plain<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		write!(self, "{thing}").unwrap();
		self
	}
	/// Append `thing` onto the buffer using the [`Display`] trait (plain uncolored text but in **bold**)
	fn push_bold<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.set_bold().unwrap();
		write!(self, "{thing}").unwrap();
		self.reset().unwrap();
		self
	}

	/// [`push_with_color`](Self::push_with_color) with [`Color::Alpha`]
	fn push_alpha<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color(Color::Alpha, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Beta`]
	fn push_beta<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color(Color::Beta, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Gamma`]
	fn push_gamma<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color(Color::Gamma, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Delta`]
	fn push_delta<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color(Color::Delta, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Zeta`]
	fn push_zeta<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color(Color::Zeta, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Iota`]
	fn push_iota<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color(Color::Iota, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Omega`]
	fn push_omega<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color(Color::Omega, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Alpha`]
	fn push_alpha_bold<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color_bold(Color::Alpha, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Beta`]
	fn push_beta_bold<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color_bold(Color::Beta, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Gamma`]
	fn push_gamma_bold<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color_bold(Color::Gamma, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Delta`]
	fn push_delta_bold<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color_bold(Color::Delta, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Zeta`]
	fn push_zeta_bold<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color_bold(Color::Zeta, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Iota`]
	fn push_iota_bold<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color_bold(Color::Iota, thing)
	}
	/// [`push_with_color`](Self::push_with_color) with [`Color::Omega`]
	fn push_omega_bold<T: Display + ?Sized>(&mut self, thing: &T) -> &mut Self {
		self.push_with_color_bold(Color::Omega, thing)
	}
	/// Append to the buffer using [`Display`] but use the provided [`Color`].
	fn push_with_color<T: Display + ?Sized>(
		&mut self,
		color: Color,
		thing: &T)
		-> &mut Self
	{
		self.write_with_color(color.get_from_static(), thing);
		self
	}
	/// Same as [`push_with_color`](Self::push_with_color) but **bold**
	fn push_with_color_bold<T: Display + ?Sized>(
		&mut self,
		color: Color,
		thing: &T)
		-> &mut Self
	{
		self.write_with_color_bold(color.get_from_static(), thing);
		self
	}

	/// Append to the buffer using [`Display`] but use any [`ColorCode`].
	fn push_with_any_color<T: Display + ?Sized>(
		&mut self,
		color: ColorCode,
		thing: &T)
		-> &mut Self
	{
		self.write_with_color(color, thing);
		self
	}
	/// Same as [`push_with_any_color`](Self::push_with_any_color) but **bold**
	fn push_with_any_color_bold<T: Display + ?Sized>(
		&mut self,
		color: ColorCode,
		thing: &T)
		-> &mut Self
	{
		self.write_with_color_bold(color, thing);
		self
	}
}

impl<T: EmitEscapes> Paint for T {}


impl Color {
	/// Retrieves the [`ColorCode`] associated with this color from the `static` [`Palette`]
	pub fn get_from_static(self) -> ColorCode {
		use Color::*;
		unsafe {
			match self {
				Alpha => PALETTE.alpha,
				Beta => PALETTE.beta,
				Gamma => PALETTE.gamma,
				Delta => PALETTE.delta,
				Zeta => PALETTE.zeta,
				Iota => PALETTE.iota,
				Omega => PALETTE.omega,
			}
		}
	}
}

impl Buffer {
	/// Add an opening tag bracket to this buffer: `[`
	pub(crate) fn tag_open(&mut self) -> &mut Self {
		self.push_with_any_color_bold(unsafe {PALETTE.tag}, "[")
	}
	/// Add a closing tag bracket to this buffer: `] `
	pub(crate) fn tag_close(&mut self) -> &mut Self {
		self.push_with_any_color_bold(unsafe {PALETTE.tag}, "] ")
	}
}

impl Palette {
	/// Get the [`ColorCode`] associated with a [`Color`]
	fn get(self, color: Color) -> ColorCode {
		use Color::*;
		match color {
			Alpha => self.alpha,
			Beta => self.beta,
			Gamma => self.gamma,
			Delta => self.delta,
			Zeta => self.zeta,
			Iota => self.iota,
			Omega => self.omega,
		}
	}
	/// *Tag* a [`Buffer`] with the colors from this [`Palette`] ([`tag`](Self::tag) and `color`)
	fn write_tag(self, buffer: &mut Buffer, color: Color, tag: &str) {
		buffer.set_bold().unwrap();

		buffer.set_color(self.tag).unwrap();
		write!(buffer, "[ ").unwrap();

		buffer.set_color(self.get(color)).unwrap();
		buffer.write_all(tag.as_bytes()).unwrap();

		buffer.set_color(self.tag).unwrap();
		write!(buffer, " ] ").unwrap();

		buffer.reset().unwrap();
	}
	const fn unpack(packed: Option<&str>) -> Option<Self> {
		let mut codes = [None; 8];
		let Some(mut unparsed) = packed else {return None};
		let mut i = 0;
		while i < (codes.len() - 1) {
			let Some((s, rest)) = split_once(unparsed, ", ") else {return None};
			codes[i] = ColorCode::from_str(s);
			i += 1;
			unparsed = rest;
		}
		codes[7] = ColorCode::from_str(unparsed);
		let [
			Some(tag),
			Some(alpha),
			Some(beta),
			Some(gamma),
			Some(delta),
			Some(zeta),
			Some(iota),
			Some(omega)
		] = codes else {return None};

		Some(Self {tag, alpha, beta, gamma, delta, zeta, iota, omega})
	}
}

impl fmt::Debug for Palette {
	/// Writes out the colors in the format expected by [`CONCILIATOR_PALETTE`](self#custom-palette).
	/// If the alternate flag is specified (i.e. `{:#?}`), the compact numeric representation is used instead.
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		let Self { tag, alpha, beta, gamma, delta, zeta, iota, omega } = self;
		let colors = [ tag, alpha, beta, gamma, delta, zeta, iota, omega ];
		if f.alternate() {
			write!(f, "{}", tag.as_number())?;
			for color in &colors[1..] {
				write!(f, ", {}", color.as_number())?;
			}
		}
		else {
			write!(f, "{tag:?}")?;
			for color in &colors[1..] {
				write!(f, ", {color:?}")?;
			}
		}
		Ok(())
	}
}

impl Print for Palette {
	fn print<C: Conciliator + ?Sized>(self, con: &C) {
		let omega = self.get(Color::Omega);
		self.write_tag(&mut con.get_line(), Color::Omega, tree::ROOT);

		let main_colors = [
			(Color::Alpha, TAGS.status),
			(Color::Beta, TAGS.info),
			(Color::Gamma, TAGS.warn),
			(Color::Delta, TAGS.error),
		];

		for (color, tag) in main_colors {
			let code = self.get(color);
			let name = format!("{color:?}");

			let mut line = con.get_line();
			line
				.push("  ")
				.push_with_any_color(omega, tree::KNOT);
			self.write_tag(&mut line, color, tag);
			line.push("\t")
				.push_with_any_color(code, "███")
				.push(" ")
				.push_with_any_color_bold(code, &format_args!("{name:6}"))
				.push(format_args!("({code:?})"));
		}
		con.get_line()
			.push("  ")
			.push_with_any_color_bold(omega, tree::STEM);

		for color in [Color::Iota, Color::Zeta] {
			let code = self.get(color);
			let name = format!("{color:?}");
			con.get_line()
				.push("  ")
				.push_with_any_color(omega, tree::KNOT)
				.push_with_any_color(code, " spare ")
				.push("\t")
				.push_with_any_color(code, "███")
				.push(" ")
				.push_with_any_color_bold(code, &format_args!("{name:6}"))
				.push(format_args!("({code:?})"));
		}
		con.get_line()
			.push("  ")
			.push_with_any_color_bold(omega, tree::TAIL)
			.push_with_any_color(omega, " branches")
			.push("\t")
			.push_with_any_color(omega, "███")
			.push(" ")
			.push_with_any_color_bold(omega, "Omega")
			.push(format_args!(" ({omega:?})"));
	}
}

const fn slice_eq(mut a: &[u8], mut b: &[u8]) -> bool {
	if a.len() != b.len() {return false;}
	while let ([a_byte, a_rest @ ..], [b_byte, b_rest @ ..]) = (a, b) {
		if *a_byte != *b_byte {return false;}
		(a, b) = (a_rest, b_rest);
	}
	true
}
const fn strip_prefix<'a>(s: &'a str, prefix: &str) -> Option<&'a str> {
	// taken from core/str/mod.rs & adapted for const as freestanding method
	// https://doc.rust-lang.org/1.76.0/src/core/str/mod.rs.html#213-236
	const fn is_char_boundary(s: &str, index: usize) -> bool {
		if index == 0 || index == s.len() {true}
		else if index > s.len() {false}
		else {is_utf8_char_boundary(s.as_bytes()[index])}
	}
	// taken from core/num/mod.rs & adapted as freestanding method
	// https://doc.rust-lang.org/1.76.0/src/core/num/mod.rs.html#1089
	const fn is_utf8_char_boundary(byte: u8) -> bool {
		// This is bit magic equivalent to: b < 128 || b >= 192
		(byte as i8) >= -0x40
	}

	if prefix.len() > s.len() {return None;}
	if !is_char_boundary(s, prefix.len()) {return None;}
	let (maybe_prefix, rest) = s.as_bytes().split_at(prefix.len());
	if !slice_eq(prefix.as_bytes(), maybe_prefix) {None}
	else {
		match from_utf8(rest) {
			Ok(stripped) => Some(stripped),
			Err(_err) => None
		}
	}
}
/// If `s` contains `delim`, return everything before and everything after it
const fn split_once<'a>(s: &'a str, delim: &str) -> Option<(&'a str, &'a str)> {
	let haystack = s.as_bytes();
	let needle = delim.as_bytes();

	if haystack.len() < needle.len() {return None;}
	let mut index = 0;
	while index + needle.len() <= haystack.len() {
		let (prefix, rest) = haystack.split_at(index);
		let (maybe_needle, rest) = rest.split_at(needle.len());
		index += 1;
		if !slice_eq(maybe_needle, needle) {continue;}

		let (Ok(prefix), Ok(rest)) = (from_utf8(prefix), from_utf8(rest)) else {
			return None;
		};
		return Some((prefix, rest));
	}
	None
}

impl Tags {
	const fn unpack(packed: Option<&'static str>) -> Option<Self> {
		let Some(packed) = packed else {return None};
		let Some(rest) = strip_prefix(packed, "[ Tags ], [ ") else {
			return None
		};
		let Some((status, rest)) = split_once(rest, " ], [ ") else {
			return None
		};
		let Some((info, rest)) = split_once(rest, " ], [ ") else {return None};
		let Some((warn, rest)) = split_once(rest, " ], [ ") else {return None};
		let Some((error, rest)) = split_once(rest, " ]") else {return None};
		if !rest.is_empty() {return None;}

		Some(Tags {status, info, warn, error})
	}
}

#[test]
fn change_palette() {
	let con = crate::init();
	con.status("Test").push_alpha("123");

	let old = get_palette();

	let new_palette = Palette {
		tag: ColorCode::IntenseWhite,

		alpha: ColorCode::Green,
		beta: ColorCode::Blue,
		gamma: ColorCode::IntenseRed,
		delta: ColorCode::Red,

		zeta: ColorCode::Magenta,
		iota: ColorCode::Cyan,

		omega: ColorCode::IntenseBlack
	};
	assert_ne!(old, new_palette);
	unsafe {set_palette(new_palette);}
	assert_eq!(new_palette, get_palette());
	con.status("Test").push_alpha("123");
}

#[test]
fn slice_eq_test() {
	let tests: [(&[u8], &[u8], bool); 7] = [
		(b"abc", b"abc", true),
		(b"", b"", true),
		(b"", b" ", false),
		(b" ", b"", false),
		(b"abc", b"123", false),
		(b"abc", b"abc123", false),
		(b"abc123", b"abc", false)
	];

	for (a, b, result) in tests {
		assert_eq!(slice_eq(a, b), result);
	}
}

#[test]
fn split_once_test() {
	let tests = [
		("x ] abc", " ] ", Some(("x", "abc"))),
		("x ]abc", " ] ", None),
		("[123] ] abc", " ] ", Some(("[123]", "abc"))),
		("x ]", " ]", Some(("x", ""))),
	];

	for (s, delim, result) in tests {
		assert_eq!(split_once(s, delim), result);
	}
}

#[test]
fn unpack_tags() {
	const PACKED_TAGS: &str = "[ Tags ], [ > ], [ + ], [ WARN ], [ ERROR ]";

	const UNPACKED: Tags = match Tags::unpack(Some(PACKED_TAGS)) {
		Some(t) => t,
		None => panic!("unpacking failed")
	};
	let Tags { status, info, warn, error } = UNPACKED;

	assert_eq!(DEFAULT_TAGS.status, status);
	assert_eq!(DEFAULT_TAGS.info, info);
	assert_eq!(DEFAULT_TAGS.warn, warn);
	assert_eq!(DEFAULT_TAGS.error, error);
}

#[test]
fn unpack_palette() {
	const PACKED_PALETTE: &str =
		"White, Blue, Green, Red, IntenseRed, Yellow, Cyan, IntenseBlack";

	const UNPACKED: Palette = match Palette::unpack(Some(PACKED_PALETTE)) {
		Some(t) => t,
		None => panic!("unpacking failed")
	};
	assert_eq!(DEFAULT_PALETTE, UNPACKED);

	const NUM_PACKED: &str = "7, 4, 2, 1, 9, 3, 6, 8";

	const NUM_UNPACKED: Palette = match Palette::unpack(Some(NUM_PACKED)) {
		Some(t) => t,
		None => panic!("unpacking failed")
	};
	assert_eq!(DEFAULT_PALETTE, NUM_UNPACKED);
}