use std::{
	ops::{Deref, DerefMut},
	sync::LazyLock,
};

use dioxus::{
	desktop::{Config, WindowBuilder},
	prelude::*,
};
use rand::seq::SliceRandom;
use serde::Deserialize;

// const FAVICON: Asset = asset!("/assets/favicon.ico");
const MAIN_CSS: Asset = asset!("/assets/main.css");
// const HEADER_SVG: Asset = asset!("/assets/header.svg");

#[derive(Debug, Deserialize)]
pub struct Questions {
	questions: Vec<Question>,
}

impl Deref for Questions {
	type Target = Vec<Question>;

	fn deref(&self) -> &Self::Target {
		&self.questions
	}
}

impl DerefMut for Questions {
	fn deref_mut(&mut self) -> &mut Self::Target {
		&mut self.questions
	}
}

#[derive(Debug, Clone, PartialEq, Deserialize)]
pub struct Question {
	message: String,
	answers: Vec<Answer>,
}

#[derive(Debug, Clone, PartialEq, Deserialize)]
pub struct Answer {
	message: String,

	#[serde(default)]
	is_correct: Option<bool>,

	#[serde(default, skip)]
	checked: bool,
}

#[derive(Debug, Props, PartialEq, Clone)]
struct QuestionProps {
	current: Question,
}

pub static QUESTIONS: LazyLock<Questions> = LazyLock::new(|| {
	let questions_str = std::fs::read_to_string("questions.toml").unwrap();
	let questions: Questions = toml::from_str(&questions_str).unwrap();
	questions
});

fn get_questions() -> Vec<Question> {
	let mut questions = QUESTIONS.questions.clone();
	let mut rng = rand::rng();

	// Randomize the answers
	questions
		.iter_mut()
		.for_each(|q| q.answers.shuffle(&mut rng));

	// Randomize the questions list
	questions.shuffle(&mut rng);

	questions
}

fn main() {
	dioxus::LaunchBuilder::new()
		.with_cfg(
			Config::default().with_menu(None).with_window(
				WindowBuilder::new()
					.with_maximized(true)
					.with_title("Flashcards"),
			),
		)
		.launch(App)
}

#[component]
fn App() -> Element {
	rsx! {
		// document::Link { rel: "icon", href: FAVICON }
		document::Link { rel: "stylesheet", href: MAIN_CSS }
		QuestionPrompt {}
	}
}

#[component]
pub fn QuestionPrompt() -> Element {
	let mut questions = use_signal(get_questions);
	let mut current = use_signal(move || questions.remove(0));

	let total_correct = use_memo(move || {
		current
			.read()
			.answers
			.iter()
			.filter(|a| a.is_correct.unwrap_or_default())
			.count()
	});
	let actual_correct = use_memo(move || {
		current
			.read()
			.answers
			.iter()
			.filter(|a| a.is_correct.unwrap_or_default() && a.checked)
			.count()
	});

	let total_questions = QUESTIONS.len();
	let current_question = use_memo(move || questions().len());
	let left_questions = use_memo(move || total_questions - current_question());

	let answer_buttons = current()
		.answers
		.into_iter()
		.enumerate()
		.map(|(i, _answer)| {
			rsx! {
				AnswerCheckbox { current, id: i }
			}
		});

	rsx! {
		div { "{left_questions}/{total_questions}" },
		form {
			id: "form",
			onsubmit: move |_| {
				if actual_correct() == total_correct() {
					current().answers.iter_mut().for_each(|a| a.checked = false);
					if !questions().is_empty() {
						current.set(questions.remove(0));
					}
					else {
						questions.set(get_questions());
						current.set(questions.remove(0));
					}
				}
			},

			h1 { "{current().message}" }
			{ answer_buttons }
			input {
				type: "submit",
			}
		}
	}
}

#[component]
pub fn AnswerCheckbox(current: Signal<Question>, id: usize) -> Element {
	let message = use_memo(move || {
		current
			.read()
			.answers
			.get(id)
			.map(|a| a.message.clone())
			.unwrap_or("???".to_string())
	});

	let checked = use_memo(move || {
		current
			.read()
			.answers
			.get(id)
			.map(|a| a.checked)
			.unwrap_or(false)
	});

	rsx! {
		div {
			class: if checked() { "selected" } else { "" },
			onclick: move |_| {
				let mut write_lock = current.write();
				if let Some(answer) = write_lock.answers.get_mut(id) {
					answer.checked = !answer.checked;
				}
			},

			input {
				id: "a{id}",
				name: "a{id}",
				type: "checkbox",
				value: "{id}",
				checked: "{checked}",
				onclick: move |event| event.prevent_default(),
			}
			label {
				for: "a{id}",
				onclick: move |event| event.prevent_default(),
				"{message}"
			},
		}
	}
}