#![allow(clippy::useless_conversion)]
#![allow(clippy::unnecessary_cast)]

use std::collections::{BTreeMap, HashMap};

use comparable::{assert_changes, Changed::*, I32Change, MapChange};

pub struct HashMapBuilder {
	elements: Vec<(i32, i32)>,
}

impl HashMapBuilder {
	fn new() -> Self {
		HashMapBuilder { elements: Vec::new() }
	}

	fn add_element(mut self, key: i32, value: i32) -> Self {
		self.elements.push((key, value));
		self
	}

	fn create(self) -> HashMap<i32, i32> {
		self.elements.into_iter().collect()
	}
}

#[test]
fn test_hashmap_example_old() {
	let mut map = HashMap::<i32, i32>::new();
	map.insert(1, 100);
	map.insert(2, 200);

	map.remove(&2);

	// But what if `map.remove` had other side-effects? We wouldn't know.
	assert_eq!(map.get(&2), None);
}

#[test]
fn test_hashmap_example_new() {
	let mut map = HashMapBuilder::new().add_element(1, 100).add_element(2, 200).create();
	let initial_map = map.clone();

	map.remove(&2);

	// We assert here that map.remove can only have had one effect.
	assert_changes!(&initial_map, &map, Changed(vec![MapChange::Removed(2)]));
}

#[test]
fn test_hashmap() {
	assert_changes!(&HashMap::<i32, i32>::new(), &HashMap::<i32, i32>::new(), Unchanged,);
	assert_changes!(
		&HashMap::new(),
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		Changed(vec![MapChange::Added(0, 1), MapChange::Added(1, 2), MapChange::Added(2, 3),]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		&HashMap::new(),
		Changed(vec![MapChange::Removed(0), MapChange::Removed(1), MapChange::Removed(2),]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2)].into_iter().collect::<HashMap<_, _>>(),
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		Changed(vec![MapChange::Added(2, 3)]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		&vec![(0, 1 as i32), (1, 2)].into_iter().collect::<HashMap<_, _>>(),
		Changed(vec![MapChange::Removed(2)]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		Changed(vec![MapChange::Added(1, 2)]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		&vec![(0, 1 as i32), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		Changed(vec![MapChange::Removed(1)]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		&vec![(0, 1 as i32), (1, 4), (2, 3)].into_iter().collect::<HashMap<_, _>>(),
		Changed(vec![MapChange::Changed(1, I32Change(2, 4))]),
	);
}

#[test]
fn test_btreemap() {
	assert_changes!(&BTreeMap::<i32, i32>::new(), &BTreeMap::<i32, i32>::new(), Unchanged,);
	assert_changes!(
		&BTreeMap::new(),
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		Changed(vec![MapChange::Added(0, 1), MapChange::Added(1, 2), MapChange::Added(2, 3),]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		&BTreeMap::new(),
		Changed(vec![MapChange::Removed(0), MapChange::Removed(1), MapChange::Removed(2),]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2)].into_iter().collect::<BTreeMap<_, _>>(),
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		Changed(vec![MapChange::Added(2, 3)]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		&vec![(0, 1 as i32), (1, 2)].into_iter().collect::<BTreeMap<_, _>>(),
		Changed(vec![MapChange::Removed(2)]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		Changed(vec![MapChange::Added(1, 2)]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		&vec![(0, 1 as i32), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		Changed(vec![MapChange::Removed(1)]),
	);
	assert_changes!(
		&vec![(0, 1 as i32), (1, 2), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		&vec![(0, 1 as i32), (1, 4), (2, 3)].into_iter().collect::<BTreeMap<_, _>>(),
		Changed(vec![MapChange::Changed(1, I32Change(2, 4))]),
	);
}