mod navigate_navigation;
mod navigation_find;
mod navigation_insert_options;
mod navigation_remove_options;
mod navigation_replace_options;
mod navigation_select_option;
mod navigation_set_options;
mod update_navigation;
mod view_navigation;
mod view_navigation_button;

#[cfg(test)]
mod dummy_navigation_option;

use std::fmt::Debug;

pub use navigation_insert_options::InsertOptionResult;

#[derive(Clone, Debug)]
pub struct Navigation<TOption> {
    options_before_active: Vec<TOption>,
    pub active_option: Option<TOption>,
    options_after_active: Vec<TOption>,
}

#[derive(Clone, Debug, PartialEq)]
pub enum Message<TOption> {
    ActivateOption(TOption),
    SelectNext,
    SelectOption(TOption),
    SelectPrev,
    SetOptions(Vec<TOption>),
}

pub enum Action<TOption> {
    ActivateOption(TOption),
    SelectOption(TOption),
    None,
}

impl<TOption: Clone + Debug + PartialEq> Navigation<TOption> {
    pub fn new(active_option: Option<TOption>, options: Vec<TOption>) -> Self {
        let active_option_index = active_option.clone().map_or(Option::None, |active_option| {
            options.iter().position(|option| option.eq(&active_option))
        });
        if let Some(active_option_index) = active_option_index {
            let split = options.split_at(active_option_index);
            Navigation {
                options_before_active: split.0.to_vec(),
                active_option: active_option,
                options_after_active: split.1.split_at(1).1.to_vec(),
            }
        } else {
            Navigation {
                options_before_active: options,
                active_option: active_option,
                options_after_active: vec![],
            }
        }
    }
}

#[cfg(test)]
mod test {
    use super::Navigation;

    #[test]
    fn when_active_option_at_start_of_options_then_finds_active_option() {
        let navigation = Navigation::new(Some(1), vec![1, 2, 3, 4, 5]);
        assert_eq!(Vec::<i32>::new(), navigation.options_before_active);
        assert_eq!(Some(1), navigation.active_option);
        assert_eq!(vec![2, 3, 4, 5], navigation.options_after_active);
    }

    #[test]
    fn when_active_option_in_middle_of_options_then_finds_active_option() {
        let navigation = Navigation::new(Some(3), vec![1, 2, 3, 4, 5]);
        assert_eq!(vec![1, 2], navigation.options_before_active);
        assert_eq!(Some(3), navigation.active_option);
        assert_eq!(vec![4, 5], navigation.options_after_active);
    }

    #[test]
    fn when_active_option_at_end_of_options_then_finds_active_option() {
        let navigation = Navigation::new(Some(5), vec![1, 2, 3, 4, 5]);
        assert_eq!(vec![1, 2, 3, 4], navigation.options_before_active);
        assert_eq!(Some(5), navigation.active_option);
        assert_eq!(Vec::<i32>::new(), navigation.options_after_active);
    }

    #[test]
    fn when_active_option_not_in_options_then_appends_active_option() {
        let navigation = Navigation::new(Some(6), vec![1, 2, 3, 4, 5]);
        assert_eq!(vec![1, 2, 3, 4, 5], navigation.options_before_active);
        assert_eq!(Some(6), navigation.active_option);
        assert_eq!(Vec::<i32>::new(), navigation.options_after_active);
    }

    #[test]
    fn when_no_active_option_then_all_options_are_before_active_option() {
        let navigation = Navigation::new(None, vec![1, 2, 3, 4, 5]);
        assert_eq!(vec![1, 2, 3, 4, 5], navigation.options_before_active);
        assert_eq!(None, navigation.active_option);
        assert_eq!(Vec::<i32>::new(), navigation.options_after_active);
    }
}