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use std::cmp::Ordering;
use crate::modes::FileInfo;
/// Different kind of sort
#[derive(Debug, Clone, Default, Copy)]
enum SortBy {
#[default]
/// Directory first
Kind,
/// by filename
File,
/// by date
Date,
/// by size
Size,
/// by extension
Exte,
}
impl std::fmt::Display for SortBy {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
let sort_by = match &self {
Self::Exte => "Exte",
Self::Date => "Date",
Self::File => "File",
Self::Size => "Size",
Self::Kind => "Kind",
};
write!(f, "{sort_by}")
}
}
/// Ascending or descending sort
#[derive(Debug, Clone, Default, Copy)]
enum Order {
#[default]
/// Ascending order
Ascending,
/// Descending order
Descending,
}
impl Order {
const fn reverse(self) -> Self {
match self {
Self::Descending => Self::Ascending,
Self::Ascending => Self::Descending,
}
}
}
#[derive(Debug, Clone, Default, Copy)]
/// Describe a way of sorting
pub struct SortKind {
/// The key used to sort the files
sort_by: SortBy,
/// Ascending or descending order
order: Order,
}
impl SortKind {
/// Default kind of sort for a tree view.
/// Since files are in reverse order, we need to sort in descending order.
#[must_use]
pub const fn tree_default() -> Self {
Self {
sort_by: SortBy::Kind,
order: Order::Descending,
}
}
/// Updates itself from a given character.
/// If the character describes a kind of sort, we apply it. (k n m s e -- K N M S E)
/// If the character is lowercase, we sort by Ascending order, else Descending order.
/// If the character is 'r' or 'R' we reverse current kind of sort.
pub fn update_from_char(&mut self, c: char) {
match c.to_ascii_uppercase() {
'K' => self.sort_by = SortBy::Kind,
'N' => self.sort_by = SortBy::File,
'M' => self.sort_by = SortBy::Date,
'S' => self.sort_by = SortBy::Size,
'E' => self.sort_by = SortBy::Exte,
'R' => self.order = self.order.reverse(),
_ => {
return;
}
}
if c != 'r' {
if c.is_uppercase() {
self.order = Order::Descending;
} else {
self.order = Order::Ascending;
}
}
}
/// Use Higher Rank Trait Bounds
/// Avoid using slices to sort a collection.
/// It allows use to use references to `String` (`&str`) instead of cloning the `String`.
/// Reference: [StackOverflow](https://stackoverflow.com/questions/56105305/how-to-sort-a-vec-of-structs-by-a-string-field)
fn sort_by_key_hrtb<T, F, K>(slice: &mut [T], f: F)
where
F: for<'a> Fn(&'a T) -> &'a K,
K: Ord + ?Sized,
{
slice.sort_unstable_by(|a, b| f(a).cmp(f(b)));
}
/// Use Higher Rank Trait Bounds
/// Avoid using slices to sort a collection.
/// It allows use to use references to `String` (`&str`) instead of cloning the `String`.
/// Reference: [StackOverflow](https://stackoverflow.com/questions/56105305/how-to-sort-a-vec-of-structs-by-a-string-field)
/// This version uses a reversed comparaison, allowing a descending sort.
fn reversed_sort_by_key_hrtb<T, F, K>(slice: &mut [T], f: F)
where
F: for<'a> Fn(&'a T) -> &'a K,
K: Ord + ?Sized,
{
slice.sort_unstable_by(|a, b| Ordering::reverse(f(a).cmp(f(b))));
}
// A second version should take 2 parameters.
// 1. the way to access the data depending on T where files: &mut [T],
// 2. a closure returning the correct data.
/// Sort a collection of file depending of enum variants.
#[rustfmt::skip]
pub fn sort(&self, files: &mut [FileInfo]) {
if matches!(self.order, Order::Ascending) {
match self.sort_by {
SortBy::Kind => files.sort_unstable_by(|a, b| natord::compare(&a.kind_format(), &b.kind_format())),
SortBy::File => files.sort_unstable_by(|a, b| natord::compare(&a.filename, &b.filename)),
SortBy::Date => Self::sort_by_key_hrtb(files, |f| &f.system_time),
SortBy::Size => Self::sort_by_key_hrtb(files, |f| &f.true_size),
SortBy::Exte => Self::sort_by_key_hrtb(files, |f| &f.extension),
}
} else {
match self.sort_by {
SortBy::Kind => files.sort_unstable_by(|a, b| natord::compare(&b.kind_format(), &a.kind_format())),
SortBy::File => files.sort_unstable_by(|a, b| natord::compare(&b.filename, &a.filename)),
SortBy::Date => Self::reversed_sort_by_key_hrtb(files, |f| &f.system_time),
SortBy::Size => Self::reversed_sort_by_key_hrtb(files, |f| &f.true_size),
SortBy::Exte => Self::reversed_sort_by_key_hrtb(files, |f| &f.extension),
}
}
}
}
impl std::fmt::Display for SortKind {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
let sort_order = match &self.order {
Order::Ascending => "↓",
Order::Descending => "↑",
};
write!(f, "{sort_by} {sort_order}", sort_by = &self.sort_by)
}
}