use iced::Element;
use crate::styles::Theme;
use crate::app::Message;

use iced::Align;
use iced::Length;
use iced::widget::text_input::{self, TextInput};
use iced::widget::scrollable::{self, Scrollable};

#[derive(Clone, Debug)]
pub struct Lyrics {
	lines: Vec<Lyric>,
	scroll_state: scrollable::State,
}

impl Lyrics {
	pub fn new() -> Self {
		let mut lyric = Lyric::new();
		lyric.select();
		Lyrics {
			lines: vec![lyric],
			scroll_state: scrollable::State::new()
		}
	}

	pub fn insert_text(&mut self, text: String) {

		let mut pieces = text.trim_end()
			.split('\n')
			.map(str::trim);

		let (line_no, current_line) = self.current_line_mut();

		current_line.deselect();
		current_line.value.push_str(pieces.next().unwrap());

		let pieces = pieces
			.collect::<Vec<_>>()
			.into_iter()
			.map(str::to_owned)
			.map(Lyric::new_with_value);
		let n_pieces = pieces.size_hint().0;

		self.lines.splice((line_no + 1)..(line_no + 1), pieces);

		self.lines[line_no + n_pieces].select();
	}

	pub fn update_line(&mut self, new_content: String, line_no: usize) {
		self.lines[line_no].value = new_content;
	}

	pub fn advance_line(&mut self, current_line: usize) {
		let new_line = current_line + 1;

		let line = if new_line == self.lines.len() {
			self.insert_line(new_line, None)
		} else {
			self.lines.get_mut(new_line)
				.expect("Unexpected .advance_line with index beyond # of lines")
		};

		line.select();

		self.lines.get_mut(current_line)
			.unwrap()
			.deselect();
	}

	pub fn insert_line(&mut self, index: usize, content: Option<String>) -> &mut Lyric {
		self.lines.insert(index, match content {
			Some(content) => Lyric::new_with_value(content),
			None => Lyric::new(),
		});
		self.lines.get_mut(index).unwrap()
	}

	pub fn current_line_mut(&mut self) -> (usize, &mut Lyric) {
		self.lines
			.iter_mut()
			.enumerate()
			.filter(|(_, l)| l.is_selected())
			.next()
			.expect("no line currently selected")
	}

	pub fn view(&mut self, theme: Theme) -> Element<Message> {
		let is_sole_line = self.lines.len() == 1;
		self.lines.iter_mut()
			.enumerate()
			.map(|(i, l)| l.view(is_sole_line, i, theme))
			.fold(Scrollable::new(&mut self.scroll_state), |s, l| s.push(l))
			.width(Length::Fill)
			.align_items(Align::Center)
			.into()
	}
}

#[derive(Clone, Debug)]
pub struct Lyric {
	state: text_input::State,
	pub value: String,
}

impl Lyric {
	pub fn new() -> Self {
		Self::new_with_value(String::with_capacity(70))
	}

	pub fn new_with_value(val: String) -> Self {
		Lyric {
			state: text_input::State::new(),
			value: val,
		}
	}

	pub fn view(&mut self, show_placeholder: bool, line_no: usize, theme: Theme) -> Element<Message> {

		let placeholder = if show_placeholder {
			"Paste some lyrics to get started"
		} else if self.state.is_focused() {
			"..."
		} else { "" };

		let size = if self.state.is_focused() { 30 } else { 20 };

		TextInput::new(
			&mut self.state,
			placeholder,
			&self.value,
			move|new_value| Message::LyricChanged { line_no, new_value },
		)
			.style(theme)
			.size(size)
			.width(Length::Units(350))
			.on_submit(Message::LineAdvanced(line_no))
			.into()
	}

	pub fn select(&mut self) {
		self.state.focus();
		self.state.move_cursor_to_end();
	}

	pub fn is_selected(&self) -> bool {
		self.state.is_focused()
	}

	pub fn deselect(&mut self) {
		self.state.unfocus();
	}
}