refactor(layouts): extract independent komorebi-layouts crate

This commit moves layout-related code into a new workspace crate
komorebi-layouts, with the intention of re-using it all in komorebi for
Mac instead of maintaining two separate implementations.

komorebi-layouts/src/custom_layout.rs

@@ -0,0 +1,278 @@
+use color_eyre::eyre;
+use color_eyre::eyre::bail;
+use serde::Deserialize;
+use serde::Serialize;
+use std::collections::HashMap;
+use std::fs::File;
+use std::io::BufReader;
+use std::ops::Deref;
+use std::ops::DerefMut;
+use std::path::Path;
+
+use super::Rect;
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+pub struct CustomLayout(Vec<Column>);
+
+impl Deref for CustomLayout {
+    type Target = Vec<Column>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for CustomLayout {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl CustomLayout {
+    pub fn from_path<P: AsRef<Path>>(path: P) -> eyre::Result<Self> {
+        let path = path.as_ref();
+        let layout: Self = match path.extension() {
+            Some(extension) if extension == "yaml" || extension == "yml" => {
+                serde_json::from_reader(BufReader::new(File::open(path)?))?
+            }
+            Some(extension) if extension == "json" => {
+                serde_json::from_reader(BufReader::new(File::open(path)?))?
+            }
+            _ => bail!("custom layouts must be json or yaml files"),
+        };
+
+        if !layout.is_valid() {
+            bail!("the layout file provided was invalid");
+        }
+
+        Ok(layout)
+    }
+
+    #[must_use]
+    pub fn column_with_idx(&self, idx: usize) -> (usize, Option<&Column>) {
+        let column_idx = self.column_for_container_idx(idx);
+        let column = self.get(column_idx);
+        (column_idx, column)
+    }
+
+    #[must_use]
+    pub fn primary_idx(&self) -> Option<usize> {
+        for (i, column) in self.iter().enumerate() {
+            if let Column::Primary(_) = column {
+                return Option::from(i);
+            }
+        }
+
+        None
+    }
+
+    #[must_use]
+    pub fn primary_width_percentage(&self) -> Option<f32> {
+        for column in self.iter() {
+            if let Column::Primary(Option::Some(ColumnWidth::WidthPercentage(percentage))) = column
+            {
+                return Option::from(*percentage);
+            }
+        }
+
+        None
+    }
+
+    pub fn set_primary_width_percentage(&mut self, percentage: f32) {
+        for column in self.iter_mut() {
+            if let Column::Primary(Option::Some(ColumnWidth::WidthPercentage(current))) = column {
+                *current = percentage;
+            }
+        }
+    }
+
+    #[must_use]
+    pub fn is_valid(&self) -> bool {
+        // A valid layout must have at least one column
+        if self.is_empty() {
+            return false;
+        };
+
+        // Vertical column splits aren't supported at the moment
+        for column in self.iter() {
+            match column {
+                Column::Tertiary(ColumnSplit::Vertical)
+                | Column::Secondary(Some(ColumnSplitWithCapacity::Vertical(_))) => return false,
+                _ => {}
+            }
+        }
+
+        // The final column must not have a fixed capacity
+        match self.last() {
+            Some(Column::Tertiary(_)) => {}
+            _ => return false,
+        }
+
+        let mut primaries = 0;
+        let mut tertiaries = 0;
+
+        for column in self.iter() {
+            match column {
+                Column::Primary(_) => primaries += 1,
+                Column::Tertiary(_) => tertiaries += 1,
+                Column::Secondary(_) => {}
+            }
+        }
+
+        // There must only be one primary and one tertiary column
+        matches!(primaries, 1) && matches!(tertiaries, 1)
+    }
+
+    pub(crate) fn column_container_counts(&self) -> HashMap<usize, usize> {
+        let mut count_map = HashMap::new();
+
+        for (idx, column) in self.iter().enumerate() {
+            match column {
+                Column::Primary(_) | Column::Secondary(None) => {
+                    count_map.insert(idx, 1);
+                }
+                Column::Secondary(Some(split)) => {
+                    count_map.insert(
+                        idx,
+                        match split {
+                            ColumnSplitWithCapacity::Vertical(n)
+                            | ColumnSplitWithCapacity::Horizontal(n) => *n,
+                        },
+                    );
+                }
+                Column::Tertiary(_) => {}
+            }
+        }
+
+        count_map
+    }
+
+    #[must_use]
+    pub fn first_container_idx(&self, col_idx: usize) -> usize {
+        let count_map = self.column_container_counts();
+        let mut container_idx_accumulator = 0;
+
+        for i in 0..col_idx {
+            if let Some(n) = count_map.get(&i) {
+                container_idx_accumulator += n;
+            }
+        }
+
+        container_idx_accumulator
+    }
+
+    #[must_use]
+    pub fn column_for_container_idx(&self, idx: usize) -> usize {
+        let count_map = self.column_container_counts();
+        let mut container_idx_accumulator = 0;
+
+        // always -1 because we don't insert the tertiary column in the count_map
+        for i in 0..self.len() - 1 {
+            if let Some(n) = count_map.get(&i) {
+                container_idx_accumulator += n;
+
+                // The accumulator becomes greater than the window container index
+                // for the first time when we reach a column that contains that
+                // window container index
+                if container_idx_accumulator > idx {
+                    return i;
+                }
+            }
+        }
+
+        // If the accumulator never reaches a point where it is greater than the
+        // window container index, then the only remaining possibility is the
+        // final tertiary column
+        self.len() - 1
+    }
+
+    #[must_use]
+    pub fn column_area(&self, work_area: &Rect, idx: usize, offset: Option<usize>) -> Rect {
+        let divisor = offset.map_or_else(|| self.len(), |offset| self.len() - offset);
+
+        #[allow(clippy::cast_possible_wrap, clippy::cast_possible_truncation)]
+        let equal_width = work_area.right / divisor as i32;
+        let mut left = work_area.left;
+        let right = equal_width;
+
+        for _ in 0..idx {
+            left += right;
+        }
+
+        Rect {
+            left,
+            top: work_area.top,
+            right,
+            bottom: work_area.bottom,
+        }
+    }
+
+    #[must_use]
+    pub fn column_area_with_last(
+        len: usize,
+        work_area: &Rect,
+        primary_right: i32,
+        last_column: Option<Rect>,
+        offset: Option<usize>,
+    ) -> Rect {
+        let divisor = offset.map_or_else(|| len - 1, |offset| len - offset - 1);
+
+        #[allow(clippy::cast_possible_wrap, clippy::cast_possible_truncation)]
+        let equal_width = (work_area.right - primary_right) / divisor as i32;
+        let left = last_column.map_or(work_area.left, |last| last.left + last.right);
+        let right = equal_width;
+
+        Rect {
+            left,
+            top: work_area.top,
+            right,
+            bottom: work_area.bottom,
+        }
+    }
+
+    #[must_use]
+    pub fn main_column_area(
+        work_area: &Rect,
+        primary_right: i32,
+        last_column: Option<Rect>,
+    ) -> Rect {
+        let left = last_column.map_or(work_area.left, |last| last.left + last.right);
+
+        Rect {
+            left,
+            top: work_area.top,
+            right: primary_right,
+            bottom: work_area.bottom,
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq)]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+#[serde(tag = "column", content = "configuration")]
+pub enum Column {
+    Primary(Option<ColumnWidth>),
+    Secondary(Option<ColumnSplitWithCapacity>),
+    Tertiary(ColumnSplit),
+}
+
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq)]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+pub enum ColumnWidth {
+    WidthPercentage(f32),
+}
+
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq)]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+pub enum ColumnSplit {
+    Horizontal,
+    Vertical,
+}
+
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq)]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+pub enum ColumnSplitWithCapacity {
+    Horizontal(usize),
+    Vertical(usize),
+}