amoxide-tui 0.10.0

use crate::model::{Column, TreeNode, TuiMessage, TuiModel};

pub fn handle(model: &mut TuiModel, msg: TuiMessage) {
    match msg {
        TuiMessage::CursorDown => {
            // Extract cursor and tree length before any mutable borrow.
            let (cursor, tree_len, next) = {
                let tree = active_tree(model);
                let cursor = *active_cursor(model);
                let next = (cursor + 1..tree.len()).find(|&i| tree[i].kind.is_navigable());
                (cursor, tree.len(), next)
            };
            let _ = (cursor, tree_len); // suppress unused-variable warnings
            if let Some(next_idx) = next {
                *active_cursor_mut(model) = next_idx;
            }
        }
        TuiMessage::CursorUp => {
            let (cursor, prev) = {
                let tree = active_tree(model);
                let cursor = *active_cursor(model);
                let prev = (0..cursor).rev().find(|&i| tree[i].kind.is_navigable());
                (cursor, prev)
            };
            let _ = cursor;
            if let Some(prev_idx) = prev {
                *active_cursor_mut(model) = prev_idx;
            }
        }
        TuiMessage::JumpTop => {
            let first = {
                let tree = active_tree(model);
                (0..tree.len()).find(|&i| tree[i].kind.is_navigable())
            };
            if let Some(first_idx) = first {
                *active_cursor_mut(model) = first_idx;
            }
        }
        TuiMessage::JumpBottom => {
            let last = {
                let tree = active_tree(model);
                (0..tree.len()).rev().find(|&i| tree[i].kind.is_navigable())
            };
            if let Some(last_idx) = last {
                *active_cursor_mut(model) = last_idx;
            }
        }
        TuiMessage::SwitchColumn => {
            if matches!(model.mode, crate::model::Mode::Transfer(_)) {
                model.active_column = match model.active_column {
                    Column::Left => Column::Right,
                    Column::Right => Column::Left,
                };
            }
        }
        _ => {}
    }
}

pub fn active_tree(model: &TuiModel) -> &[TreeNode] {
    match model.active_column {
        Column::Left => &model.tree,
        Column::Right => &model.dest_tree,
    }
}

pub fn active_cursor(model: &TuiModel) -> &usize {
    match model.active_column {
        Column::Left => &model.cursor,
        Column::Right => &model.dest_cursor,
    }
}

pub fn active_cursor_mut(model: &mut TuiModel) -> &mut usize {
    match model.active_column {
        Column::Left => &mut model.cursor,
        Column::Right => &mut model.dest_cursor,
    }
}