use std::fs;

use iced::{
    Color, Element, Renderer, Subscription, Task, Theme,
    alignment::{Horizontal, Vertical},
    color, event,
    keyboard::{self, Key, key},
    theme, widget,
};

mod data;

macro_rules! data {
    () => {
        dirs::data_dir().unwrap().join("fridge.ron")
    };
}

#[derive(Clone, Debug)]
enum Message {
    AddCategory,
    RemoveCategory {
        i_category: usize,
    },
    CategoryChanged {
        i_category: usize,
        new_value: String,
    },

    AddElement {
        i_category: usize,
    },
    RemoveElement {
        i_category: usize,
        i_element: usize,
    },
    MoveElement {
        i_category: usize,
        i_element: usize,
        target_category: usize,
    },
    ElementChanged {
        i_category: usize,
        i_element: usize,
        new_value: String,
    },

    EditNotes(widget::text_editor::Action),

    Event(iced::Event),
}

#[derive(Clone, Debug, Default)]
struct State {
    table: data::Table,
    content: widget::text_editor::Content,

    /// has the application initialized successfully?
    ok: bool,
}
impl State {
    fn new() -> Self {
        let mut state = Self::default();
        if let Ok(str) =
            fs::read_to_string(data!()).inspect_err(|e| eprintln!("failed to open data file: {e}"))
        {
            let saved = ron::de::from_str::<data::Saved>(&str).unwrap();
            state.table = saved.table;
            state.content = widget::text_editor::Content::with_text(&saved.notes);
        }

        state.ok = true;

        state
    }
    fn view(&self) -> Element<'_, Message, Theme, Renderer> {
        widget::column([
            widget::button("add category")
                .on_press(Message::AddCategory)
                .into(),
            widget::row(self.table.iter().enumerate().map(|(i_category, category)| {
                widget::column([
                    widget::row([
                        widget::text_input("category", &category.header)
                            .on_input(move |new_value| Message::CategoryChanged {
                                i_category,
                                new_value,
                            })
                            .size(30)
                            .into(),
                        widget::button("X")
                            .style(widget::button::danger)
                            .on_press(Message::RemoveCategory { i_category })
                            .height(50)
                            .into(),
                    ])
                    .align_y(Vertical::Center)
                    .into(),
                    widget::scrollable(
                        widget::column(category.elements.iter().enumerate().map(
                            |(i_element, element)| {
                                widget::row([
                                    widget::text_input("content", element)
                                        .on_input(move |new_value| Message::ElementChanged {
                                            i_category,
                                            i_element,
                                            new_value,
                                        })
                                        .into(),
                                    widget::button("◄")
                                        .on_press_maybe(if i_category > 0 {
                                            Some(Message::MoveElement {
                                                i_category,
                                                i_element,
                                                target_category: i_category - 1,
                                            })
                                        } else {
                                            None
                                        })
                                        .into(),
                                    widget::button("►")
                                        .on_press_maybe(if i_category < self.table.len() - 1 {
                                            Some(Message::MoveElement {
                                                i_category,
                                                i_element,
                                                target_category: i_category + 1,
                                            })
                                        } else {
                                            None
                                        })
                                        .into(),
                                    widget::button("X")
                                        .style(widget::button::warning)
                                        .on_press(Message::RemoveElement {
                                            i_category,
                                            i_element,
                                        })
                                        .into(),
                                ])
                                .into()
                            },
                        ))
                        .align_x(Horizontal::Center)
                        .push(
                            widget::button("add element")
                                .on_press(Message::AddElement { i_category }),
                        ),
                    )
                    .into(),
                ])
                .align_x(Horizontal::Center)
                .into()
            }))
            .spacing(15)
            .into(),
        ])
        .push(widget::text_editor(&self.content).on_action(Message::EditNotes))
        .align_x(Horizontal::Center)
        .spacing(15)
        .padding(15)
        .into()
    }
    fn update(&mut self, message: Message) -> Task<Message> {
        match message {
            Message::AddCategory => {
                self.table.push(Default::default());
            }
            Message::RemoveCategory { i_category } => {
                self.table.remove(i_category);
            }
            Message::CategoryChanged {
                i_category,
                new_value,
            } => {
                self.table[i_category].header = new_value;
            }

            Message::AddElement { i_category } => {
                self.table[i_category].elements.push(Default::default());
            }
            Message::RemoveElement {
                i_category,
                i_element,
            } => {
                self.table[i_category].elements.remove(i_element);
            }
            Message::MoveElement {
                i_category,
                i_element,
                target_category,
            } => {
                let moved_element = self.table[i_category].elements.remove(i_element);
                self.table[target_category].elements.reverse();
                self.table[target_category].elements.push(moved_element);
                self.table[target_category].elements.reverse();
            }
            Message::ElementChanged {
                i_category,
                i_element,
                new_value,
            } => {
                self.table[i_category].elements[i_element] = new_value;
            }

            Message::EditNotes(action) => {
                self.content.perform(action);
            }

            Message::Event(iced::Event::Keyboard(keyboard::Event::KeyPressed {
                key,
                modifiers,
                ..
            })) => match key.as_ref() {
                // input field cycling
                Key::Named(key::Named::Tab) => {
                    if modifiers.shift() {
                        return widget::operation::focus_previous();
                    } else {
                        return widget::operation::focus_next();
                    }
                }

                // ignore unused keys
                _ => {}
            },

            // ignore unused events
            Message::Event(_) => {}
        }

        Task::none()
    }

    fn subscription(&self) -> Subscription<Message> {
        event::listen().map(Message::Event)
    }
}
impl Drop for State {
    fn drop(&mut self) {
        if !self.ok {
            eprintln!("app failed to start, not saving data");
            return;
        }

        ron::Options::default()
            .to_io_writer(
                fs::File::create(data!()).unwrap(),
                &data::Saved {
                    table: self.table.clone(),
                    notes: self.content.text(),
                },
            )
            .unwrap();

        eprintln!("successfully saved data");
    }
}

fn main() -> Result<(), iced::Error> {
    iced::application(State::new, State::update, State::view)
        .subscription(State::subscription)
        .theme(Theme::custom(
            "custom",
            theme::Palette {
                background: color!(0x080808),
                text: Color::WHITE,
                primary: color!(0xff00ff),
                success: color!(0x00ff00),
                warning: color!(0x880000),
                danger: color!(0xff0000),
            },
        ))
        .run()
}