use crate::static_data::Statistic;
use std::fmt::Debug;
use std::sync::Arc;

/// A nature is an attribute on a Pokemon that modifies the effective base stats on a Pokemon. They
/// can have an increased statistic and a decreased statistic, or be neutral.
pub trait Nature: Debug {
    /// The stat that should receive the increased modifier.
    fn increased_stat(&self) -> Statistic;

    /// The stat that should receive the decreased modifier.
    fn decreased_stat(&self) -> Statistic;

    /// The amount that the increased stat gets modified by.
    fn increased_modifier(&self) -> f32;

    /// The amount that the decreased stat gets modified by.
    fn decreased_modifier(&self) -> f32;

    /// Calculates the modifier for a given stat. If it's the increased stat, returns the increased
    /// modifier, if it's the decreased stat, returns the decreased modifier. Otherwise returns 1.0
    fn get_stat_modifier(&self, stat: Statistic) -> f32;

    /// Checks if two natures are equal.
    fn eq(&self, other: &dyn Nature) -> bool;
}

/// A nature is an attribute on a Pokemon that modifies the effective base stats on a Pokemon. They
/// can have an increased statistic and a decreased statistic, or be neutral.
#[derive(Debug)]
pub struct NatureImpl {
    /// The stat that should receive the increased modifier.
    increase_stat: Statistic,
    /// The stat that should receive the decreased modifier.
    decrease_stat: Statistic,
    /// The amount by which the increased stat is multiplied.
    increase_modifier: f32,
    /// The amount by which the decreased stat is multiplied.
    decrease_modifier: f32,
}

impl NatureImpl {
    /// Instantiates a new nature.
    pub fn new(
        increase_stat: Statistic,
        decrease_stat: Statistic,
        increase_modifier: f32,
        decrease_modifier: f32,
    ) -> Arc<Self> {
        Arc::new(Self {
            increase_stat,
            decrease_stat,
            increase_modifier,
            decrease_modifier,
        })
    }
}

impl Nature for NatureImpl {
    /// The stat that should receive the increased modifier.
    fn increased_stat(&self) -> Statistic {
        self.increase_stat
    }

    /// The stat that should receive the decreased modifier.
    fn decreased_stat(&self) -> Statistic {
        self.decrease_stat
    }

    fn increased_modifier(&self) -> f32 {
        self.increase_modifier
    }

    fn decreased_modifier(&self) -> f32 {
        self.decrease_modifier
    }

    /// Calculates the modifier for a given stat. If it's the increased stat, returns the increased
    /// modifier, if it's the decreased stat, returns the decreased modifier. Otherwise returns 1.0
    fn get_stat_modifier(&self, stat: Statistic) -> f32 {
        if stat == self.increase_stat && stat != self.decrease_stat {
            self.increase_modifier
        } else if stat == self.decrease_stat && stat != self.increase_stat {
            self.decrease_modifier
        } else {
            1.0
        }
    }

    fn eq(&self, other: &dyn Nature) -> bool {
        std::ptr::eq(self, other as *const dyn Nature as *const Self)
    }
}

#[cfg(test)]
#[allow(clippy::indexing_slicing)]
#[allow(clippy::unwrap_used)]
pub(crate) mod tests {
    use super::*;

    mockall::mock! {
        #[derive(Debug)]
        pub Nature {}
        impl Nature for Nature {
            fn increased_stat(&self) -> Statistic;
            fn decreased_stat(&self) -> Statistic;
            fn increased_modifier(&self) -> f32;
            fn decreased_modifier(&self) -> f32;
            fn get_stat_modifier(&self, stat: Statistic) -> f32;
            fn eq(&self, other: &dyn Nature) -> bool;
        }
    }
}