//! Provides some operations to be used on the [`Text`] or [`Rich`].
//!
//! [`Text`]: crate::text::Text
//! [`Rich`]: crate::text::Rich

use crate::core::widget::operation::{self, Operation};

/// Some selected text
pub struct Selection(pub String);

/// Some mutable independent selection field of a [`Text`] or [`Rich`] that can be changed through
/// an operation.
///
/// [`Text`]: crate::text::Text
/// [`Rich`]: crate::text::Rich
pub struct IndependentSelection(pub std::cell::RefCell<bool>);

impl IndependentSelection {
    /// Creates a new [`IndependentSelection`] with the given value.
    pub fn new(value: bool) -> Self {
        Self(std::cell::RefCell::new(value))
    }

    /// Gets the inner bool value of this [`IndependentSelection`].
    pub fn get(&self) -> bool {
        *self.0.borrow()
    }
}

/// Gets all the currently selected text
pub fn selected() -> impl Operation<String> {
    struct CopySelection {
        contents: Vec<String>,
    }

    impl Operation<String> for CopySelection {
        fn traverse(
            &mut self,
            operate: &mut dyn FnMut(&mut dyn Operation<String>),
        ) {
            operate(self);
        }

        fn custom(
            &mut self,
            _id: Option<&iced_widget::Id>,
            _bounds: iced_widget::core::Rectangle,
            _state: &mut dyn std::any::Any,
        ) {
            if let Some(selection) = _state.downcast_ref::<Selection>() {
                self.contents.push(selection.0.clone());
            }
        }

        fn finish(&self) -> operation::Outcome<String> {
            if !self.contents.is_empty() {
                let clipboard =
                    self.contents.iter().fold(String::new(), |mut str, s| {
                        if str.is_empty() {
                            str = s.to_owned();
                        } else {
                            str.push('\n');
                            str.push_str(s);
                        }
                        str
                    });
                operation::Outcome::Some(clipboard)
            } else {
                operation::Outcome::None
            }
        }
    }

    CopySelection {
        contents: Vec::new(),
    }
}

/// Sets all children instances of [`Text`] or [`Rich`] to be globally selectable instead of
/// independently selectable.
///
/// [`Text`]: crate::text::Text
/// [`Rich`]: crate::text::Rich
pub fn global_selection() -> impl Operation {
    struct SetGlobalSelection;

    impl Operation for SetGlobalSelection {
        fn traverse(&mut self, operate: &mut dyn FnMut(&mut dyn Operation)) {
            operate(self);
        }

        fn custom(
            &mut self,
            _id: Option<&iced_widget::Id>,
            _bounds: iced_widget::core::Rectangle,
            _state: &mut dyn std::any::Any,
        ) {
            if let Some(selection) =
                _state.downcast_mut::<IndependentSelection>()
            {
                let _ = selection.0.replace(false);
            }
        }
    }

    SetGlobalSelection
}