use anyhow_ext::Result;
use std::sync::Arc;

use indexmap::IndexMap;

use crate::Random;
use crate::StringKey;

/// A data library is a collection of methods to set up a default library, where values are stored
/// by both key, while keeping their insertion order.
pub trait DataLibrary<T: ?Sized> {
    /// Returns the underlying map.
    fn map(&self) -> &IndexMap<StringKey, Arc<T>>;
    /// Returns the underlying map in mutable manner.
    fn get_modify(&mut self) -> &mut IndexMap<StringKey, Arc<T>>;

    /// Adds a new value to the library.
    fn add(&self, key: &StringKey, value: Arc<T>) {
        #[allow(clippy::unwrap_used)] // We know this cant fail.
        let self_mut = unsafe { (self as *const Self as *mut Self).as_mut() }.unwrap();
        self_mut.get_modify().insert(key.clone(), value);
    }

    /// Removes a value from the library.
    fn remove(&self, key: &StringKey) {
        #[allow(clippy::unwrap_used)] // We know this cant fail.
        let self_mut = unsafe { (self as *const Self as *mut Self).as_mut() }.unwrap();
        self_mut.get_modify().remove(key);
    }

    /// Gets a value from the library.
    fn get(&self, key: &StringKey) -> Option<Arc<T>> {
        self.map().get::<StringKey>(key).cloned()
    }

    /// Gets a value from the library.
    fn get_by_hash(&self, key: u32) -> Option<Arc<T>> {
        self.map().get::<u32>(&key).cloned()
    }

    /// Gets a value from the library by the index where it is stored.
    fn get_key_by_index(&self, index: usize) -> Option<StringKey> {
        self.map().get_index(index).map(|a| a.0.clone())
    }

    /// Gets the amount of values in the library.
    fn len(&self) -> usize {
        self.map().len()
    }
    /// Returns whether the library has no values.
    fn is_empty(&self) -> bool {
        self.map().is_empty()
    }

    /// Gets a random value from the library.
    fn random_value(&self, rand: &mut Random) -> Result<&Arc<T>> {
        let i = rand.get_between(0, self.len() as i32);
        match self.map().get_index(i as usize) {
            Some(v) => Ok(v.1),
            None => anyhow::bail!("No value found for index {}", i),
        }
    }
}