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use crate::config::CONFIG;
use crate::wiki::article::{Element, ElementType};
use cursive::theme::Style;
use cursive::Vec2;
use std::collections::HashMap;
use std::mem;
use std::rc::Rc;
/// An element only containing the neccessary information for rendering (and an id so that it can
/// be referenced to an article element
#[derive(Debug)]
pub struct RenderedElement {
/// The id of the ArticleElement this element belongs to
pub id: usize,
/// The content of the element
pub content: String,
/// The style of the element
pub style: Style,
/// The width of the element. Measured by the amount of characters in the content
pub width: usize,
}
impl RenderedElement {
/// Appends a string to the content of the element
pub fn push_str(&mut self, string: &str) {
self.width += string.chars().count();
self.content.push_str(string);
}
/// Appends a character to the content of the element
pub fn push(&mut self, char: char) {
self.width += 1;
self.content.push(char);
}
}
pub type Line = Vec<RenderedElement>;
/// Generates lines of elements in constrained width
pub struct LinesWrapper {
/// The line that is currently being rendered
current_line: Line,
/// The width of the current line
current_width: usize,
/// The maximal width a line can have
width: usize,
/// The length of the longest rendered line
pub max_width: usize,
/// Are any lines wrapped?
pub is_wrapped: bool,
/// A referece to the article elements
elements: Rc<Vec<Element>>,
/// The rendered lines
pub rendered_lines: Vec<Line>,
/// The y-coordinates of every anchor encountered
pub anchors: HashMap<String, usize>,
/// The ids and positions of the links
pub links: Vec<(usize, Vec2)>,
}
impl LinesWrapper {
/// Creates a new LinesWrapper with a content and constraint
pub fn new(width: usize, elements: Rc<Vec<Element>>) -> Self {
LinesWrapper {
current_line: Line::new(),
current_width: 0,
width,
max_width: 0,
is_wrapped: false,
elements,
rendered_lines: Vec::new(),
links: Vec::new(),
anchors: HashMap::new(),
}
}
/// Wraps the lines and returns the required width. This method is way cheaper than wrap_lines
/// because it only calculates the required width and nothing else
pub fn required_width(mut self) -> usize {
debug!("calculating the required with");
// go through every elment
for element in self.elements.iter() {
// does this element go onto a new line?
if element.kind() == ElementType::Newline {
// "add" the element onto a new line
self.current_line = Line::new();
self.current_width = element.width();
// store the width of the element if it is the biggest one yet
if element.width() > self.max_width {
self.max_width = element.width();
continue;
}
}
// does it fit into the current line?
if element.width() + self.current_width < self.width {
// yay, it fits
// add its width to the current line
self.current_width += element.width();
// store the width of the element if it is the biggest one yet
if element.width() > self.max_width {
self.max_width = element.width();
continue;
}
}
// if it doesn't fit, return 0
debug!("the lines are wrapped, returning 0");
return 0;
}
debug!("finished with a required size of '{}'", self.max_width);
self.max_width
}
/// Starts the wrapping process
#[must_use]
pub fn wrap_lines(mut self) -> Self {
debug!("wrapping the lines");
let mut last_type: ElementType = ElementType::Text;
// go through every element
for element in self.elements.clone().iter() {
// is this a link?
let is_link = element.kind() == ElementType::Link;
// does this element go onto a new line?
if element.kind() == ElementType::Newline {
// fill the current line and make the next one blank
self.fill_line();
self.newline();
last_type = element.kind();
continue;
}
// what we do here is fairly simple:
// First, we split the content into words and then we merge these words together until the
// line is full. Then we create a new one and do the same thing over and over again until
// we run out of words.
let mut merged_element = RenderedElement {
id: element.id(),
style: element.style(),
content: String::new(),
width: 0,
};
// now our lines are wrapped
self.is_wrapped = true;
// if the element does not have a leading special character and we are not at the beginning
// of a line, add a leading whitespace
if (!element.content().starts_with([',', '.', ';', ':'])
&& !self.current_line.is_empty())
|| last_type == ElementType::ListMarker
{
self.push_whitespace();
}
for span in element.content().split_whitespace() {
// does the span fit onto the current line?
if span.chars().count() + merged_element.width + self.current_width < self.width {
// only add a leading whitespace if the merged element is not empty
if !merged_element.content.is_empty() {
merged_element.push(' ');
}
// then add it to the merged element
merged_element.push_str(span);
last_type = element.kind();
continue;
}
// now we have to do the following things:
// - add the merged element to the current line
// - fill the current line and replace it with a new one
// - add the span to a new merged element
self.current_width += merged_element.width;
self.current_line.push(merged_element);
// if its a link, add it
if is_link {
self.register_link(element.id())
}
if let Some(anchor) = element.attr("anchor") {
self.anchors
.insert(anchor.to_string(), self.rendered_lines.len());
}
self.fill_line();
self.newline();
merged_element = RenderedElement {
id: element.id(),
style: element.style(),
content: String::new(),
width: 0,
};
// does the span fit onto the current line?
if span.chars().count() + merged_element.width + self.current_width < self.width {
// only add a leading whitespace if the merged element is not empty
if !merged_element.content.is_empty() {
merged_element.push(' ');
}
// then add it to the merged element
merged_element.push_str(span);
last_type = element.kind();
continue;
}
}
// if there are still some spans in the merged_element, add it to the current line and
// register a link if it is one
if !merged_element.content.is_empty() {
self.current_width += merged_element.width;
self.current_line.push(merged_element);
if is_link {
self.register_link(element.id());
}
if let Some(anchor) = element.attr("anchor") {
self.anchors
.insert(anchor.to_string(), self.rendered_lines.len());
}
}
}
debug!("'{}' anchors found and registered", self.anchors.len());
debug!("'{}' links found", self.links.len());
debug!("wrapped '{}' lines", self.rendered_lines.len());
self
}
/// Registers a new link with the given id
fn register_link(&mut self, id: usize) {
self.links
.push((id, Vec2::new(self.current_width, self.rendered_lines.len())))
}
/// Adds an element to the current line and if needed, registers a link to it
fn push_element(&mut self, element: RenderedElement) {
self.current_width += element.width;
self.current_line.push(element);
}
/// Adds a whitespacde to the current line
fn push_whitespace(&mut self) {
// check if we can add a whitespace
if self.current_width == self.width {
return;
}
// create a rendered element with the id -1 and push it to the current line
self.push_element(RenderedElement {
id: usize::MAX,
content: " ".to_string(),
style: Style::from(CONFIG.theme.text),
width: 1,
});
}
/// Adds the current line to the rendered lines and replaces it with a new, empty one
fn newline(&mut self) {
// add the current line to the rendered lines
self.rendered_lines.push(mem::take(&mut self.current_line));
// and reset the current line afterwards
self.current_width = 0;
}
/// Fills the remaining space of the line with spaces
fn fill_line(&mut self) {
// if our current line is wider than allowed, we really messed up
assert!(self.current_width <= self.width);
// change the max width, if neccessary
if self.current_width > self.max_width {
self.max_width = self.current_width;
}
// just create an empty element that filles the whole line
let remaining_width = self.width - self.current_width;
self.create_rendered_element(
&usize::MAX,
&Style::none(),
&" ".repeat(remaining_width),
&remaining_width,
);
}
/// Creates a rendered element and adds it to the current line
fn create_rendered_element(&mut self, id: &usize, style: &Style, content: &str, width: &usize) {
// we can just clone the whole thing and call the push_element function
self.push_element(RenderedElement {
id: *id,
style: *style,
content: {
// if the line is empty, remove leading whitespace
if self.current_line.is_empty() {
content.trim_start().to_string()
} else {
content.to_string()
}
},
width: *width,
});
}
}