use serde::{Deserialize, Serialize};

#[derive(Debug, Clone, PartialEq, Eq, Default, Serialize, Deserialize)]
#[serde(tag = "kind", rename_all = "lowercase")]
pub enum Patch<T> {
    #[default]
    Unchanged,
    Clear,
    Set(T),
}

impl<T> Patch<T> {
    pub fn is_unchanged(&self) -> bool {
        matches!(self, Self::Unchanged)
    }

    pub fn apply_to_option(&self, slot: &mut Option<T>)
    where
        T: Clone,
    {
        match self {
            Self::Unchanged => {}
            Self::Clear => *slot = None,
            Self::Set(value) => *slot = Some(value.clone()),
        }
    }

    pub fn into_db_patch(self) -> Option<Option<T>> {
        match self {
            Self::Unchanged => None,
            Self::Clear => Some(None),
            Self::Set(value) => Some(Some(value)),
        }
    }
}

impl Patch<String> {
    pub fn apply_to_command_option(&self, slot: &mut Option<String>) {
        match self {
            Self::Unchanged => {}
            Self::Clear => *slot = None,
            Self::Set(value) => *slot = Some(value.trim().to_owned()),
        }
    }
}

impl Patch<&str> {
    pub fn apply_to_command_option(&self, slot: &mut Option<String>) {
        match self {
            Self::Unchanged => {}
            Self::Clear => *slot = None,
            Self::Set(value) => *slot = Some(value.trim().to_owned()),
        }
    }
}