#![allow(dead_code)]
use super::*;

pub fn fit_text(text: &str, t: &Theme, size: Vec2) -> (Vec2, f32) {
	let scale = t.font_size;
	let text_size = Text::size(text, &t.font, scale);
	if text_size.x() > 0. {
		let r = size.div(text_size);
		let r = r.x().min(r.y() * 2.).min(1.);
		(size.sub(text_size.mul(r)).mul(0.5), scale * r)
	} else {
		((size.x(), size.y() - scale).mul(0.5), scale)
	}
}

type LinesWraps = (Box<[STR]>, Box<[u32]>);

pub fn parse_text(t: &str, f: &Font, s: f32, m: f32) -> LinesWraps {
	parse_text_impl(t, f, s, m, false, |_| false)
}
pub fn parse_text_by(t: &str, f: &Font, s: f32, m: f32, linebreak: impl Fn(char) -> bool) -> LinesWraps {
	parse_text_impl(t, f, s, m, true, linebreak)
}
fn parse_text_impl(text: &str, font: &Font, scale: f32, max_w: f32, split: bool, split_by: impl Fn(char) -> bool) -> LinesWraps {
	if text.is_empty() {
		return (Box([""]), Box([1]));
	}

	let (mut lnum, mut lines, mut wraps) = (1, vec![], vec![]);

	for mut l in text.lines() {
		if l.is_empty() {
			lines.push("");
			wraps.push(lnum);
			lnum += 1;
		}
		while !l.is_empty() {
			let (head, tail) = {
				let (_, (head, tail)) = Text::substr(l, font, scale, max_w);
				match tail {
					"" => (head, tail),
					_ if l.len() == tail.len() => {
						let second_char = l.char_indices().map(|(i, _)| i).nth(1).unwrap_or(l.len());
						l.split_at(second_char)
					}
					_ if !split || tail.starts_with(&split_by) => (head, tail),
					_ => {
						/* Traditional   ^head.ends  V.map(|h| l[h..].char_indices().map(|(i, _)| h + i).nth(1)).flatten() */
						let h = head.rfind(&split_by).unwrap_or(head.len());
						if h > 0 {
							l.split_at(h)
						} else {
							(head, tail)
						}
					}
				}
			};
			let e = tail.is_empty();
			lines.push(unsafe { mem::transmute(head) });
			wraps.push(lnum.or_def(e));
			lnum += u32(e);
			l = tail;
		}
	}
	(lines.into(), wraps.into())
}

pub fn caret_x(text: &str, t: &Theme, scale: f32, at: usize, pad: f32) -> f32 {
	let font = &t.font;
	let past_end = at > text.utf8_len();
	let last_ch = Text::char_at(text, font, scale, at);
	let adv = Text::adv_at(text, font, scale, at);
	let last_w = (last_ch.adv - pad).or_def(past_end);
	let empty_x = pad.or_def(text.is_empty());
	adv + last_ch.coord.x() + last_w + empty_x
}

pub fn move_caret(lines: &[&str], (x, y): Caret, (ox, oy): iVec2, clamp_x: bool) -> Caret {
	let (x, ox, y, oy) = ilVec4((x, ox, y, oy));
	let last_idx = lines.last_idx();
	let y = usize((y + oy).clamp(0, isize(last_idx)));
	let text = lines[y];
	let x = {
		let x = x + ox;
		if x + ox < 1 {
			if y == 0 {
				return (1, 0);
			};
			let skip = isize(lines[y - 1].utf8_len() + 1);
			return move_caret(lines, (0, y - 1), iVec2((x + skip, 0)), true);
		}
		if clamp_x && x > isize(text.utf8_len() + 1) {
			if y == last_idx {
				return (lines[last_idx].utf8_len() + 1, last_idx);
			};
			return move_caret(lines, Caret::to((x - isize(text.utf8_len() + 1), y + 1)), (0, 0), true);
		}
		x
	};
	Caret::to((x, y))
}

pub fn caret_to_cursor(lines: &[&str], (start, len): Vec2, t: &Theme, scale: f32, pos: Vec2, (x, y): Vec2) -> Caret {
	let (b, e) = ilVec2((start, start + len));
	let y = isize(start + (pos.y() - y) / scale).clamp(b - 1, e);
	let text = line(lines, (0, y));
	let ((caret_x, _), (str, _)) = Text::substr(text, &t.font, scale, x - pos.x());
	let past_end = x > pos.x() + caret_x;
	let c = (str.utf8_len(), usize(y.max(0)));
	let o = (1.or_def(past_end), 0);
	move_caret(lines, c, o, true)
}

pub fn clamp(lines: &[&str], c: Caret) -> Caret {
	c.clmp((1, 0), (line(lines, c).utf8_len() + 1, lines.last_idx()))
}

pub fn line<'a, X, Y>(lines: &'a [&str], caret: (X, Y)) -> &'a str
where
	vec2<isize>: Cast<(X, Y)>,
{
	let (_, y) = ilVec2(caret);
	let y = y.clamp(0, isize(lines.last_idx()));
	if !lines.is_empty() {
		lines.at(y)
	} else {
		""
	}
}

pub type Caret = ulVec2;