use std::path::PathBuf;

use iced::advanced::widget::Id;
use iced::widget::pane_grid::{self, Pane, PaneGrid};
use iced::widget::{container, pick_list, row, text_editor, Column};
use iced::{clipboard, keyboard, Alignment, Element, Length, Task, Theme};
use iced_anim::{Animation, Spring};
use iced_builder::config::Config;
use iced_builder::dialogs::{
    error_dialog, unsaved_changes_dialog, warning_dialog,
};
use iced_builder::panes::{code_view, designer_view, element_list};
use iced_builder::types::{
    Action, DesignerPage, ElementName, Message, Project,
};
use iced_builder::{icon, Error};
use rfd::MessageDialogResult;
use tokio::runtime;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let config_load = {
        let rt = runtime::Builder::new_current_thread()
            .enable_all()
            .build()?;

        rt.block_on(Config::load())
    };

    iced::application(App::title, App::update, App::view)
        .font(icon::FONT)
        .theme(|state| state.theme.value().clone())
        .subscription(App::subscription)
        .run_with(move || App::new(config_load))?;

    Ok(())
}

struct App {
    is_dirty: bool,
    is_loading: bool,
    project_path: Option<PathBuf>,
    project: Project,
    config: Config,
    theme: Spring<Theme>,
    pane_state: pane_grid::State<Panes>,
    focus: Option<Pane>,
    designer_page: DesignerPage,
    element_list: &'static [ElementName],
    editor_content: text_editor::Content,
}

#[derive(Clone, Copy, Debug)]
enum Panes {
    Designer,
    ElementList,
}

impl App {
    fn new(config_load: Result<Config, Error>) -> (Self, Task<Message>) {
        let state = pane_grid::State::with_configuration(
            pane_grid::Configuration::Split {
                axis: pane_grid::Axis::Vertical,
                ratio: 0.8,
                a: Box::new(pane_grid::Configuration::Pane(Panes::Designer)),
                b: Box::new(pane_grid::Configuration::Pane(Panes::ElementList)),
            },
        );

        let config = match config_load {
            Ok(config) => {
                println!("{config:?}");
                config
            }
            Err(_) => Config::default(),
        };

        let theme = config.selected_theme();

        let mut task = Task::none();

        if let Some(path) = config.last_project.clone() {
            if path.exists() && path.is_file() {
                task = Task::perform(
                    Project::from_path(path),
                    Message::FileOpened,
                );
            } else {
                warning_dialog(format!(
                    "The file {} does not exist, or isn't a file.",
                    path.to_string_lossy().to_string()
                ));
            }
        }

        (
            Self {
                is_dirty: false,
                is_loading: false,
                project_path: None,
                project: Project::new(),
                config,
                theme: Spring::new(theme),
                pane_state: state,
                focus: None,
                designer_page: DesignerPage::DesignerView,
                element_list: ElementName::ALL,
                editor_content: text_editor::Content::new(),
            },
            task,
        )
    }

    fn title(&self) -> String {
        let saved_state = if !self.is_dirty { "" } else { " *" };

        let project_name = match &self.project.title {
            Some(n) => {
                format!(
                    " - {}",
                    if n.len() > 60 {
                        format!("...{}", &n[n.len() - 40..])
                    } else {
                        n.to_owned()
                    }
                )
            }
            None => "".to_owned(),
        };

        format!("iced Builder{project_name}{saved_state}")
    }

    fn update(&mut self, message: Message) -> Task<Message> {
        match message {
            Message::ToggleTheme(event) => {
                self.theme.update(event);
            }
            Message::CopyCode => {
                return clipboard::write(self.editor_content.text())
            }
            Message::SwitchPage(page) => self.designer_page = page,
            Message::EditorAction(action) => {
                if let text_editor::Action::Scroll { lines: _ } = action {
                    self.editor_content.perform(action);
                }
            }
            Message::RefreshEditorContent => {
                match self.project.clone().app_code(&self.config) {
                    Ok(code) => {
                        self.editor_content =
                            text_editor::Content::with_text(&code);
                    }
                    Err(error) => error_dialog(error.to_string()),
                }
            }
            Message::DropNewElement(name, point, _) => {
                return iced_drop::zones_on_point(
                    move |zones| Message::HandleNew(name.clone(), zones),
                    point,
                    None,
                    None,
                )
                .into()
            }
            Message::HandleNew(name, zones) => {
                let ids: Vec<Id> = zones.into_iter().map(|z| z.0).collect();
                if ids.len() > 0 {
                    let action = Action::new(
                        ids,
                        &mut self.project.element_tree.clone(),
                        None,
                    );
                    let result = name.handle_action(
                        self.project.element_tree.as_mut(),
                        action,
                    );
                    match result {
                        Ok(Some(ref element)) => {
                            self.project.element_tree = Some(element.clone())
                        }
                        Err(error) => error_dialog(error.to_string()),
                        _ => {}
                    }

                    self.is_dirty = true;
                    return Task::done(Message::RefreshEditorContent);
                }
            }
            Message::MoveElement(element, point, _) => {
                return iced_drop::zones_on_point(
                    move |zones| Message::HandleMove(element.clone(), zones),
                    point,
                    None,
                    None,
                )
                .into()
            }
            Message::HandleMove(element, zones) => {
                let ids: Vec<Id> = zones.into_iter().map(|z| z.0).collect();
                if ids.len() > 0 {
                    let action = Action::new(
                        ids,
                        &mut self.project.element_tree.clone(),
                        Some(element.get_id()),
                    );
                    let result = element.handle_action(
                        self.project.element_tree.as_mut(),
                        action,
                    );
                    if let Err(error) = result {
                        error_dialog(error.to_string());
                    }

                    self.is_dirty = true;
                    return Task::done(Message::RefreshEditorContent);
                }
            }
            Message::PaneResized(pane_grid::ResizeEvent { split, ratio }) => {
                self.pane_state.resize(split, ratio);
            }
            Message::PaneClicked(pane) => {
                self.focus = Some(pane);
            }
            Message::PaneDragged(pane_grid::DragEvent::Dropped {
                pane,
                target,
            }) => {
                self.pane_state.drop(pane, target);
            }
            Message::PaneDragged(_) => {}
            Message::NewFile => {
                if !self.is_loading {
                    if !self.is_dirty {
                        self.project = Project::new();
                        self.project_path = None;
                        self.editor_content = text_editor::Content::new();
                    } else {
                        if let MessageDialogResult::Ok = unsaved_changes_dialog("You have unsaved changes. Do you wish to discard these and create a new project?") {
                            self.is_dirty = false;
                            self.project = Project::new();
                            self.project_path = None;
                            self.editor_content = text_editor::Content::new();
                        }
                    }
                }
            }
            Message::OpenFile => {
                if !self.is_loading {
                    if !self.is_dirty {
                        self.is_loading = true;

                        return Task::perform(
                            Project::from_file(),
                            Message::FileOpened,
                        );
                    } else {
                        if let MessageDialogResult::Ok = unsaved_changes_dialog("You have unsaved changes. Do you wish to discard these and open another project?") {
                            self.is_dirty = false;
                            self.is_loading = true;
                            return Task::perform(Project::from_file(), Message::FileOpened);
                        }
                    }
                }
            }
            Message::FileOpened(result) => {
                self.is_loading = false;
                self.is_dirty = false;

                match result {
                    Ok((path, project)) => {
                        self.project = project.clone();
                        self.project_path = Some(path);
                        self.editor_content = text_editor::Content::with_text(
                            &project
                                .app_code(&self.config)
                                .unwrap_or_else(|err| err.to_string()),
                        );
                    }
                    Err(error) => error_dialog(error.to_string()),
                }
            }
            Message::SaveFile => {
                if !self.is_loading {
                    self.is_loading = true;

                    return Task::perform(
                        self.project
                            .clone()
                            .write_to_file(self.project_path.clone()),
                        Message::FileSaved,
                    );
                }
            }
            Message::SaveFileAs => {
                if !self.is_loading {
                    self.is_loading = true;

                    return Task::perform(
                        self.project.clone().write_to_file(None),
                        Message::FileSaved,
                    );
                }
            }
            Message::FileSaved(result) => {
                self.is_loading = false;

                match result {
                    Ok(path) => {
                        self.project_path = Some(path);
                        self.is_dirty = false;
                    }
                    Err(error) => error_dialog(error.to_string()),
                }
            }
        }

        Task::none()
    }

    fn subscription(&self) -> iced::Subscription<Message> {
        keyboard::on_key_press(|key, modifiers| {
            if modifiers.command() {
                match key.as_ref() {
                    keyboard::Key::Character("o") => Some(Message::OpenFile),
                    keyboard::Key::Character("s") => {
                        Some(if modifiers.shift() {
                            Message::SaveFileAs
                        } else {
                            Message::SaveFile
                        })
                    }
                    keyboard::Key::Character("n") => Some(Message::NewFile),
                    _ => None,
                }
            } else {
                None
            }
        })
    }

    fn view(&self) -> Element<'_, Message> {
        let header = row![pick_list(
            self.config.theme.all.clone(),
            Some(self.theme.target().clone()),
            |theme| { Message::ToggleTheme(theme.into()) }
        )]
        .width(200);
        let pane_grid =
            PaneGrid::new(&self.pane_state, |id, pane, _is_maximized| {
                let is_focused = Some(id) == self.focus;
                match pane {
                    Panes::Designer => match &self.designer_page {
                        DesignerPage::DesignerView => designer_view::view(
                            &self.project.element_tree,
                            self.project.get_theme(&self.config),
                            is_focused,
                        ),
                        DesignerPage::CodeView => code_view::view(
                            &self.editor_content,
                            self.theme.target().clone(),
                            is_focused,
                        ),
                    },
                    Panes::ElementList => {
                        element_list::view(self.element_list, is_focused)
                    }
                }
            })
            .width(Length::Fill)
            .height(Length::Fill)
            .spacing(10)
            .on_resize(10, Message::PaneResized)
            .on_click(Message::PaneClicked)
            .on_drag(Message::PaneDragged);

        let content = Column::new()
            .push(header)
            .push(pane_grid)
            .spacing(5)
            .align_x(Alignment::Center)
            .width(Length::Fill);

        Animation::new(&self.theme, container(content).height(Length::Fill))
            .on_update(Message::ToggleTheme)
            .into()
    }
}