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//! Configurations related to the the search order.
use super::{Config, Coord, Symmetry};
use auto_enums::auto_enum;
use std::{borrow::Cow, cmp::Ordering};
#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};
/// The order to find a new unknown cell.
///
/// It will always search all generations of one cell
/// before going to another cell.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum SearchOrder {
/// Searches all cells of one row before going to the next row.
///
/// ```plaintext
/// 123
/// 456
/// 789
/// ```
RowFirst,
/// Searches all cells of one column before going to the next column.
///
/// ```plaintext
/// 147
/// 258
/// 369
/// ```
ColumnFirst,
/// Diagonal.
///
/// ```plaintext
/// 136
/// 258
/// 479
/// ```
///
/// This search order requires the world to be square.
Diagonal,
/// Specify the search order by a vector of coordinates.
///
/// This vector should cover every cell in the search range,
/// and should not have any duplication, otherwise rlifesrc
/// would give a wrong result.
FromVec(Vec<Coord>),
}
impl Config {
/// Automatically determines the search order if `search_order` is `None`.
pub(crate) fn auto_search_order(&self) -> Cow<'_, SearchOrder> {
if let Some(search_order) = &self.search_order {
Cow::Borrowed(search_order)
} else {
let (width, height) = match self.symmetry {
Symmetry::D2Row => (self.width, (self.height + 1) / 2),
Symmetry::D2Col => ((self.width + 1) / 2, self.height),
_ => (self.width, self.height),
};
let search_order = match width.cmp(&height) {
Ordering::Greater => SearchOrder::ColumnFirst,
Ordering::Less => SearchOrder::RowFirst,
Ordering::Equal => {
if self.diagonal_width.is_some()
&& 2 * self.diagonal_width.unwrap() <= self.width
{
SearchOrder::Diagonal
} else if self.dx.abs() >= self.dy.abs() {
SearchOrder::ColumnFirst
} else {
SearchOrder::RowFirst
}
}
};
Cow::Owned(search_order)
}
}
/// Generates an iterator over cells coordinates from the search order.
#[auto_enum(Iterator)]
pub(crate) fn search_order_iter(
&self,
search_order: &SearchOrder,
) -> impl Iterator<Item = Coord> {
let width = self.width;
let height = self.height;
let period = self.period;
let x_start = if self.symmetry >= Symmetry::D2Col {
self.width / 2
} else {
0
};
let y_start = if self.symmetry >= Symmetry::D2Row {
self.height / 2
} else {
0
};
match search_order {
SearchOrder::ColumnFirst => (0..width).rev().flat_map(move |x| {
(y_start..height)
.rev()
.flat_map(move |y| (0..period).rev().map(move |t| (x, y, t)))
}),
SearchOrder::RowFirst => (0..height).rev().flat_map(move |y| {
(x_start..width)
.rev()
.flat_map(move |x| (0..period).rev().map(move |t| (x, y, t)))
}),
#[nested]
SearchOrder::Diagonal => {
if self.symmetry >= Symmetry::D2Diag {
(0..width)
.rev()
.flat_map(move |d| {
((width + d + 1) / 2..width).rev().flat_map(move |x| {
(0..period).rev().map(move |t| (x, width + d - x, t))
})
})
.chain((0..width).rev().flat_map(move |d| {
((d + 1) / 2..=d)
.rev()
.flat_map(move |x| (0..period).rev().map(move |t| (x, d - x, t)))
}))
} else {
(0..width)
.rev()
.flat_map(move |d| {
(d + 1..width).rev().flat_map(move |x| {
(0..period).rev().map(move |t| (x, width + d - x, t))
})
})
.chain((0..width).rev().flat_map(move |d| {
(0..=d)
.rev()
.flat_map(move |x| (0..period).rev().map(move |t| (x, d - x, t)))
}))
}
}
SearchOrder::FromVec(vec) => vec.clone().into_iter().rev(),
}
}
/// Generates a closure to determine whether a cell is in the front.
///
/// Return `None` when we should not force the front to be nonempty,
/// or there isn't a well-defined 'front'.
pub(crate) fn fn_is_front(
&self,
rule_is_b0: bool,
rule_gen: usize,
rule_symmetry: Symmetry,
search_order: &SearchOrder,
) -> Option<Box<dyn Fn(Coord) -> bool>> {
let dx = self.dx;
let dy = self.dy;
let width = self.width;
let height = self.height;
let max_t = if rule_is_b0 { rule_gen as i32 } else { 1 };
if !self.known_cells.is_empty() {
return None;
}
match search_order {
SearchOrder::RowFirst => {
if self.symmetry <= Symmetry::D2Col
&& self.transform.is_in(Symmetry::D2Col)
&& self.diagonal_width.is_none()
{
if dx == 0 && dy >= 0 {
if rule_symmetry >= Symmetry::D2Col {
Some(Box::new(move |(x, y, t)| {
y == (dy - 1).max(0) && t < max_t && x <= width / 2
}))
} else {
Some(Box::new(move |(_, y, t)| y == (dy - 1).max(0) && t < max_t))
}
} else if rule_symmetry >= Symmetry::D2Col && dx == 0 {
Some(Box::new(move |(x, y, _)| y == 0 && x <= width / 2))
} else {
Some(Box::new(|(_, y, _)| y == 0))
}
} else {
None
}
}
SearchOrder::ColumnFirst => {
if self.symmetry <= Symmetry::D2Row
&& self.transform.is_in(Symmetry::D2Row)
&& self.diagonal_width.is_none()
{
if dx >= 0 && dy == 0 {
if rule_symmetry >= Symmetry::D2Row {
Some(Box::new(move |(x, y, t)| {
x == (dx - 1).max(0) && t < max_t && y <= height / 2
}))
} else {
Some(Box::new(move |(x, _, t)| x == (dx - 1).max(0) && t < max_t))
}
} else if rule_symmetry >= Symmetry::D2Row && dy == 0 {
Some(Box::new(move |(x, y, _)| x == 0 && y <= height / 2))
} else {
Some(Box::new(|(x, _, _)| x == 0))
}
} else {
None
}
}
SearchOrder::Diagonal => {
if self.symmetry <= Symmetry::D2Diag && self.transform.is_in(Symmetry::D2Diag) {
if dx >= 0 && dx == dy {
if rule_symmetry >= Symmetry::D2Diag && self.width == self.height {
Some(Box::new(move |(x, _, t)| x == (dx - 1).max(0) && t < max_t))
} else {
Some(Box::new(move |(x, y, t)| {
(x == (dx - 1).max(0) || y == (dy - 1).max(0)) && t < max_t
}))
}
} else if rule_symmetry >= Symmetry::D2Diag
&& dx == dy
&& self.width == self.height
{
Some(Box::new(|(x, _, _)| x == 0))
} else {
Some(Box::new(|(x, y, _)| x == 0 || y == 0))
}
} else {
None
}
}
SearchOrder::FromVec(_) => None,
}
}
}