cargo-kconfig 0.0.1

/*
 Cargo KConfig - KConfig parser
 Copyright (C) 2022  Sjoerd van Leent

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Licensed under the Apache License, Version 2.0 (the "License"); you may not use
this file except in compliance with the License. You may obtain a copy of the
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Unless required by applicable law or agreed to in writing, software distributed
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it under the terms of the GNU General Public License as published by
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This program is distributed in the hope that it will be useful,
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

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along with this program.  If not, see <https://www.gnu.org/licenses/>.

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the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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*/
use std::{fmt::Debug, vec::IntoIter};

use unicode_width::UnicodeWidthChar;

/// Cursor position of a text input
#[derive(Debug)]
pub(crate) struct CursorPos {
    x_left: usize,
    y_top: usize,
    x_right: usize,
    y_bottom: usize,
    x: usize,
    y: usize,
    lines_omitted: usize,
    codepoints: Vec<char>,
}

impl CursorPos {
    /// Creates a new cursor position, given the text bounds
    pub(crate) fn new(
        x_left: usize,
        y_top: usize,
        x_right: usize,
        y_bottom: usize,
        codepoints: &Vec<char>,
        offset: usize,
    ) -> Self {
        let mut pos = Self {
            x_left,
            y_top,
            x_right,
            y_bottom,
            x: x_left,
            y: y_top,
            lines_omitted: 0,
            codepoints: codepoints.clone(),
        };

        let mut index = 0;
        for i in codepoints {
            if index < offset {
                pos.next(i);
                index += 1;
            }
        }

        pos
    }

    pub(crate) fn x(&self) -> usize {
        self.x
    }

    pub(crate) fn y(&self) -> usize {
        self.y
    }

    fn next(&mut self, c: &char) {
        match c {
            '\n' => self.newline(),
            ' '.. => {
                self.x += match c.width() {
                    Some(n) => n,
                    None => 0,
                }
            }
            _ => (),
        }

        if self.x_right < self.x {
            self.x = self.x_left;
            self.y += 1;
        }

        if (self.y_bottom / 2) < self.y {
            self.y = self.y_bottom / 2;
            self.lines_omitted += 1;
        }
    }

    fn newline(&mut self) {
        self.y += 1;
        self.x = self.x_left;
    }
}

/// Determines the character positions given the cursor position and
/// the place the characters need to be rendered
pub(crate) struct CharPositions {
    v: Vec<CharPos>,
}

impl CharPositions {
    pub(crate) fn new(cursor_pos: &CursorPos) -> CharPositions {
        let mut cp = CharPositions { v: Vec::new() };

        let mut lines_ommitted = 0;
        let mut x = cursor_pos.x_left;
        let mut y = cursor_pos.y_top;

        for c in &cursor_pos.codepoints {
            if y > cursor_pos.y_bottom {
                break;
            }

            match c {
                '\n' => {
                    if cursor_pos.lines_omitted > lines_ommitted {
                        lines_ommitted += 1;
                        cp.v = Vec::new()
                    } else {
                        y += 1;
                        x = cursor_pos.x_left;
                    }
                }
                ' '.. => {
                    if x > cursor_pos.x_right {
                        if cursor_pos.lines_omitted > lines_ommitted {
                            lines_ommitted += 1;
                            cp.v = Vec::new();
                        } else {
                            x = cursor_pos.x_left;
                            y += 1;
                        }
                    } else {
                        cp.v.push(CharPos { x, y, c: *c });
                        x += 1;
                    }
                }
                _ => (),
            }
        }

        cp
    }
}

impl IntoIterator for CharPositions {
    type Item = CharPos;
    type IntoIter = IntoIter<Self::Item>;
    fn into_iter(self) -> Self::IntoIter {
        IntoIterator::into_iter(self.v)
    }
}

/// Character position of text input
pub(crate) struct CharPos {
    pub(self) x: usize,
    pub(self) y: usize,
    pub(self) c: char,
}

impl CharPos {
    pub fn x(&self) -> usize {
        self.x
    }

    pub fn y(&self) -> usize {
        self.y
    }

    pub fn c(&self) -> char {
        self.c
    }
}