use iced::button;
use iced::scrollable;
use iced::slider;
use iced::text_input;
use iced::{
    Alignment, Button, Checkbox, Column, Container, Element, Length,
    ProgressBar, Radio, Row, Rule, Sandbox, Scrollable, Settings, Slider,
    Space, Text, TextInput, Theme, Toggler,
};

pub fn main() -> iced::Result {
    Styling::run(Settings::default())
}

#[derive(Default)]
struct Styling {
    theme: style::Theme,
    scroll: scrollable::State,
    input: text_input::State,
    input_value: String,
    button: button::State,
    slider: slider::State,
    slider_value: f32,
    checkbox_value: bool,
    toggler_value: bool,
}

#[derive(Debug, Clone)]
enum Message {
    ThemeChanged(style::Theme),
    InputChanged(String),
    ButtonPressed,
    SliderChanged(f32),
    CheckboxToggled(bool),
    TogglerToggled(bool),
}

impl Sandbox for Styling {
    type Message = Message;

    fn new() -> Self {
        Styling::default()
    }

    fn title(&self) -> String {
        String::from("Styling - Iced")
    }

    fn update(&mut self, message: Message) {
        match message {
            Message::ThemeChanged(theme) => self.theme = theme,
            Message::InputChanged(value) => self.input_value = value,
            Message::ButtonPressed => {}
            Message::SliderChanged(value) => self.slider_value = value,
            Message::CheckboxToggled(value) => self.checkbox_value = value,
            Message::TogglerToggled(value) => self.toggler_value = value,
        }
    }

    fn view(&mut self) -> Element<Message> {
        let choose_theme = style::Theme::ALL.iter().fold(
            Column::new().spacing(10).push(Text::new("Choose a theme:")),
            |column, theme| {
                column.push(Radio::new(
                    *theme,
                    format!("{:?}", theme),
                    Some(self.theme),
                    Message::ThemeChanged,
                ))
            },
        );

        let text_input = TextInput::new(
            &mut self.input,
            "Type something...",
            &self.input_value,
            Message::InputChanged,
        )
        .padding(10)
        .size(20)
        .style(self.theme);

        let button = Button::new(&mut self.button, Text::new("Submit"))
            .padding(10)
            .on_press(Message::ButtonPressed);

        let slider = Slider::new(
            &mut self.slider,
            0.0..=100.0,
            self.slider_value,
            Message::SliderChanged,
        );

        let progress_bar = ProgressBar::new(0.0..=100.0, self.slider_value);

        let scrollable = Scrollable::new(&mut self.scroll)
            .width(Length::Fill)
            .height(Length::Units(100))
            .style(self.theme)
            .push(Text::new("Scroll me!"))
            .push(Space::with_height(Length::Units(800)))
            .push(Text::new("You did it!"));

        let checkbox = Checkbox::new(
            self.checkbox_value,
            "Check me!",
            Message::CheckboxToggled,
        )
        .style(self.theme);

        let toggler = Toggler::new(
            self.toggler_value,
            String::from("Toggle me!"),
            Message::TogglerToggled,
        )
        .width(Length::Shrink)
        .spacing(10);

        let content = Column::new()
            .spacing(20)
            .padding(20)
            .max_width(600)
            .push(choose_theme)
            .push(Rule::horizontal(38))
            .push(Row::new().spacing(10).push(text_input).push(button))
            .push(slider)
            .push(progress_bar)
            .push(
                Row::new()
                    .spacing(10)
                    .height(Length::Units(100))
                    .align_items(Alignment::Center)
                    .push(scrollable)
                    .push(Rule::vertical(38))
                    .push(
                        Column::new()
                            .width(Length::Shrink)
                            .spacing(20)
                            .push(checkbox)
                            .push(toggler),
                    ),
            );

        Container::new(content)
            .width(Length::Fill)
            .height(Length::Fill)
            .center_x()
            .center_y()
            .into()
    }

    fn theme(&self) -> Theme {
        match self.theme {
            style::Theme::Light => Theme::Light,
            style::Theme::Dark => Theme::Dark,
        }
    }
}

mod style {
    use iced::{checkbox, scrollable, text_input};

    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
    pub enum Theme {
        Light,
        Dark,
    }

    impl Theme {
        pub const ALL: [Theme; 2] = [Theme::Light, Theme::Dark];
    }

    impl Default for Theme {
        fn default() -> Theme {
            Theme::Light
        }
    }

    impl<'a> From<Theme> for Box<dyn text_input::StyleSheet + 'a> {
        fn from(theme: Theme) -> Self {
            match theme {
                Theme::Light => Default::default(),
                Theme::Dark => dark::TextInput.into(),
            }
        }
    }

    impl<'a> From<Theme> for Box<dyn scrollable::StyleSheet + 'a> {
        fn from(theme: Theme) -> Self {
            match theme {
                Theme::Light => Default::default(),
                Theme::Dark => dark::Scrollable.into(),
            }
        }
    }

    impl<'a> From<Theme> for Box<dyn checkbox::StyleSheet + 'a> {
        fn from(theme: Theme) -> Self {
            match theme {
                Theme::Light => Default::default(),
                Theme::Dark => dark::Checkbox.into(),
            }
        }
    }

    mod dark {
        use iced::{checkbox, scrollable, text_input, Color};

        const SURFACE: Color = Color::from_rgb(
            0x40 as f32 / 255.0,
            0x44 as f32 / 255.0,
            0x4B as f32 / 255.0,
        );

        const ACCENT: Color = Color::from_rgb(
            0x6F as f32 / 255.0,
            0xFF as f32 / 255.0,
            0xE9 as f32 / 255.0,
        );

        const ACTIVE: Color = Color::from_rgb(
            0x72 as f32 / 255.0,
            0x89 as f32 / 255.0,
            0xDA as f32 / 255.0,
        );

        const HOVERED: Color = Color::from_rgb(
            0x67 as f32 / 255.0,
            0x7B as f32 / 255.0,
            0xC4 as f32 / 255.0,
        );

        pub struct TextInput;

        impl text_input::StyleSheet for TextInput {
            fn active(&self) -> text_input::Style {
                text_input::Style {
                    background: SURFACE.into(),
                    border_radius: 2.0,
                    border_width: 0.0,
                    border_color: Color::TRANSPARENT,
                }
            }

            fn focused(&self) -> text_input::Style {
                text_input::Style {
                    border_width: 1.0,
                    border_color: ACCENT,
                    ..self.active()
                }
            }

            fn hovered(&self) -> text_input::Style {
                text_input::Style {
                    border_width: 1.0,
                    border_color: Color { a: 0.3, ..ACCENT },
                    ..self.focused()
                }
            }

            fn placeholder_color(&self) -> Color {
                Color::from_rgb(0.4, 0.4, 0.4)
            }

            fn value_color(&self) -> Color {
                Color::WHITE
            }

            fn selection_color(&self) -> Color {
                ACTIVE
            }
        }

        pub struct Scrollable;

        impl scrollable::StyleSheet for Scrollable {
            fn active(&self) -> scrollable::Scrollbar {
                scrollable::Scrollbar {
                    background: SURFACE.into(),
                    border_radius: 2.0,
                    border_width: 0.0,
                    border_color: Color::TRANSPARENT,
                    scroller: scrollable::Scroller {
                        color: ACTIVE,
                        border_radius: 2.0,
                        border_width: 0.0,
                        border_color: Color::TRANSPARENT,
                    },
                }
            }

            fn hovered(&self) -> scrollable::Scrollbar {
                let active = self.active();

                scrollable::Scrollbar {
                    background: Color { a: 0.5, ..SURFACE }.into(),
                    scroller: scrollable::Scroller {
                        color: HOVERED,
                        ..active.scroller
                    },
                    ..active
                }
            }

            fn dragging(&self) -> scrollable::Scrollbar {
                let hovered = self.hovered();

                scrollable::Scrollbar {
                    scroller: scrollable::Scroller {
                        color: Color::from_rgb(0.85, 0.85, 0.85),
                        ..hovered.scroller
                    },
                    ..hovered
                }
            }
        }

        pub struct Checkbox;

        impl checkbox::StyleSheet for Checkbox {
            fn active(&self, is_checked: bool) -> checkbox::Style {
                checkbox::Style {
                    background: if is_checked { ACTIVE } else { SURFACE }
                        .into(),
                    checkmark_color: Color::WHITE,
                    border_radius: 2.0,
                    border_width: 1.0,
                    border_color: ACTIVE,
                    text_color: None,
                }
            }

            fn hovered(&self, is_checked: bool) -> checkbox::Style {
                checkbox::Style {
                    background: Color {
                        a: 0.8,
                        ..if is_checked { ACTIVE } else { SURFACE }
                    }
                    .into(),
                    ..self.active(is_checked)
                }
            }
        }
    }
}