fp-library 0.17.0

use fp_library::{
	brands::*,
	classes::{
		optics::*,
		profunctor::*,
	},
	functions::*,
	types::optics::*,
};

#[test]
fn test_lens_optic() {
	#[derive(Clone, Debug, PartialEq)]
	struct Person {
		name: String,
		age: i32,
	}

	let age_lens: LensPrime<RcBrand, Person, i32> = LensPrime::from_view_set(
		|p: Person| p.age,
		|(p, age)| Person {
			age,
			..p
		},
	);

	let person = Person {
		name: "Alice".to_string(),
		age: 30,
	};

	// To use 'evaluate', we must provide a concrete Profunctor implementation.
	// `RcFnBrand` provides a Strong + Choice Profunctor for reference-counted closures.
	//
	// Profunctor encoding of a Lens:
	//   Lens S A = forall p. Strong p => p A A -> p S S
	//
	// When p is a Function (->):
	//   evaluate :: (A -> A) -> (S -> S)
	//
	// Passing a modification function `f: A -> A` returns a function `S -> S`
	// that applies `f` to the focused field.

	let modify_age = |x: i32| x + 1;

	// Wrap the closure in the Profunctor (RcFnBrand)
	let p_modify = lift_fn_new::<RcFnBrand, _, _>(modify_age);

	// Evaluate the optic to get the modifier function
	let modifier = Optic::<RcFnBrand, _, _, _, _>::evaluate(&age_lens, p_modify);

	let updated = modifier(person.clone());
	assert_eq!(updated.age, 31);
	assert_eq!(updated.name, "Alice");
}

#[test]
fn test_composition() {
	#[derive(Clone, Debug, PartialEq)]
	struct Inner {
		val: i32,
	}

	#[derive(Clone, Debug, PartialEq)]
	struct Outer {
		inner: Inner,
	}

	let outer_lens: LensPrime<RcBrand, Outer, Inner> = LensPrime::from_view_set(
		|o: Outer| o.inner.clone(),
		|(_, i)| Outer {
			inner: i,
		},
	);
	let inner_lens: LensPrime<RcBrand, Inner, i32> = LensPrime::from_view_set(
		|i: Inner| i.val,
		|(_, v)| Inner {
			val: v,
		},
	);

	// Compose: Outer -> Inner -> i32
	// O1: Lens<Outer, Inner>
	// O2: Lens<Inner, i32>
	let composed = optics_compose(outer_lens, inner_lens);

	let obj = Outer {
		inner: Inner {
			val: 10,
		},
	};

	let modify_val = |x: i32| x * 2;
	let p_modify = lift_fn_new::<RcFnBrand, _, _>(modify_val);

	let modifier = Optic::<RcFnBrand, _, _, _, _>::evaluate(&composed, p_modify);

	let result = modifier(obj);
	assert_eq!(result.inner.val, 20);
}

#[test]
fn test_profunctor_dimap() {
	// Test that functions are profunctors
	let f = lift_fn_new::<RcFnBrand, _, _>(|x: i32| x + 1);
	let g = dimap::<RcFnBrand, _, _, _, _>(|x: i32| x * 2, |x: i32| x - 1, f);

	assert_eq!(g(10), 20); // (10 * 2) + 1 - 1 = 20
}

#[test]
fn test_strong_first() {
	let f = lift_fn_new::<RcFnBrand, _, _>(|x: i32| x + 1);
	let g = first::<RcFnBrand, _, _, i32>(f);

	assert_eq!(g((10, 20)), (11, 20));
}

#[test]
fn test_strong_second() {
	let f = lift_fn_new::<RcFnBrand, _, _>(|x: i32| x + 1);
	let g = second::<RcFnBrand, _, _, i32>(f);

	assert_eq!(g((20, 10)), (20, 11));
}

#[test]
fn test_choice_left() {
	let f = lift_fn_new::<RcFnBrand, _, _>(|x: i32| x + 1);
	let g = left::<RcFnBrand, _, _, String>(f);

	// `left` lifts a profunctor transformation `p a b` to `p (Result a c) (Result b c)`.
	// Following the PureScript/Haskell convention for Choice:
	//   left  :: p a b -> p (Either a c) (Either b c)
	//   Err(a) -> Err(f(a))
	//   Ok(c)  -> Ok(c)

	assert_eq!(g(Err(10)), Err(11));
	assert_eq!(g(Ok("success".to_string())), Ok("success".to_string()));
}

#[test]
fn test_choice_right() {
	let f = lift_fn_new::<RcFnBrand, _, _>(|x: i32| x + 1);
	let g = right::<RcFnBrand, _, _, String>(f);

	// `right` lifts a profunctor transformation `p a b` to `p (Result c a) (Result c b)`.
	//   right :: p a b -> p (Either c a) (Either c b)
	//   Ok(a)  -> Ok(f(a))
	//   Err(c) -> Err(c)

	assert_eq!(g(Ok(10)), Ok(11));
	assert_eq!(g(Err("error".to_string())), Err("error".to_string()));
}

#[test]
fn test_lens_polymorphic() {
	#[derive(Clone, Debug, PartialEq)]
	struct Poly<A> {
		val: A,
	}

	// Lens that changes Poly<i32> to Poly<String>
	let l: Lens<RcBrand, Poly<i32>, Poly<String>, i32, String> = Lens::from_view_set(
		|p: Poly<i32>| p.val,
		|(_, s)| Poly {
			val: s,
		},
	);

	let p = Poly {
		val: 42,
	};
	assert_eq!(l.view(p.clone()), 42);

	let p2 = l.set(p, "hello".to_string());
	assert_eq!(p2.val, "hello".to_string());
}

#[test]
fn test_lens_prime_over() {
	let l: LensPrime<RcBrand, i32, i32> = LensPrime::from_view_set(|x: i32| x, |(_, y)| y);
	assert_eq!(l.over(10, |x| x + 5), 15);
}

#[test]
fn test_composed_deep() {
	#[derive(Clone, Debug, PartialEq)]
	struct C {
		val: i32,
	}
	#[derive(Clone, Debug, PartialEq)]
	struct B {
		c: C,
	}
	#[derive(Clone, Debug, PartialEq)]
	struct A {
		b: B,
	}

	let a_b: LensPrime<RcBrand, A, B> = LensPrime::from_view_set(
		|a: A| a.b.clone(),
		|(_, b)| A {
			b,
		},
	);
	let b_c: LensPrime<RcBrand, B, C> = LensPrime::from_view_set(
		|b: B| b.c.clone(),
		|(_, c)| B {
			c,
		},
	);
	let c_val: LensPrime<RcBrand, C, i32> = LensPrime::from_view_set(
		|c: C| c.val,
		|(_, val)| C {
			val,
		},
	);

	let a_c = optics_compose(a_b, b_c);
	let a_val = optics_compose(a_c, c_val);

	let obj = A {
		b: B {
			c: C {
				val: 1,
			},
		},
	};

	// Composed optics don't have .view()/.set() directly, but can be used via evaluate
	let modifier = Optic::<RcFnBrand, _, _, _, _>::evaluate(
		&a_val,
		lift_fn_new::<RcFnBrand, _, _>(|x: i32| x + 10),
	);
	let result = modifier(obj.clone());
	assert_eq!(result.b.c.val, 11);

	// We can also use evaluate with Category::identity to just view (using Forget profunctor would be better but we don't have it here)
	// For now, let's just test that evaluate works on the composed optic.
}

#[test]
fn test_polymorphic_view_composed() {
	#[derive(Clone, Debug, PartialEq)]
	struct Address {
		street: String,
	}

	#[derive(Clone, Debug, PartialEq)]
	struct User {
		address: Address,
	}

	let address_lens: LensPrime<RcBrand, User, Address> = LensPrime::from_view_set(
		|u: User| u.address.clone(),
		|(_, a)| User {
			address: a,
		},
	);
	let street_lens: LensPrime<RcBrand, Address, String> = LensPrime::from_view_set(
		|a: Address| a.street.clone(),
		|(_, s)| Address {
			street: s,
		},
	);

	let user_street = optics_compose(address_lens, street_lens);
	let user = User {
		address: Address {
			street: "High St".to_string(),
		},
	};

	// Now we can use optics_view on a Composed optic!
	// This was not possible before Approach 4.
	let street = optics_view::<RcBrand, _, _>(&user_street, user);
	assert_eq!(street, "High St");
}

#[test]
fn test_polymorphic_set_composed() {
	#[derive(Clone, Debug, PartialEq)]
	struct Address {
		street: String,
	}

	#[derive(Clone, Debug, PartialEq)]
	struct User {
		address: Address,
	}

	let address_lens: LensPrime<RcBrand, User, Address> = LensPrime::from_view_set(
		|u: User| u.address.clone(),
		|(_, a)| User {
			address: a,
		},
	);
	let street_lens: LensPrime<RcBrand, Address, String> = LensPrime::from_view_set(
		|a: Address| a.street.clone(),
		|(_, s)| Address {
			street: s,
		},
	);

	let user_street = optics_compose(address_lens, street_lens);
	let user = User {
		address: Address {
			street: "High St".to_string(),
		},
	};

	let updated = optics_set::<RcBrand, _, _>(&user_street, user, "Main St".to_string());
	assert_eq!(updated.address.street, "Main St");
}

#[test]
fn test_polymorphic_preview_prism() {
	let ok_prism: PrismPrime<RcBrand, Result<i32, String>, i32> =
		PrismPrime::from_option(|r: Result<i32, String>| r.ok(), Ok);

	assert_eq!(optics_preview::<RcBrand, _, _>(&ok_prism, Ok(42)), Some(42));
	assert_eq!(optics_preview::<RcBrand, _, _>(&ok_prism, Err("error".to_string())), None);
}

#[test]
fn test_polymorphic_preview_composed_lens_prism() {
	#[derive(Clone, Debug, PartialEq)]
	struct Address {
		street: String,
	}

	#[derive(Clone, Debug, PartialEq)]
	struct User {
		address: Address,
	}

	let address_lens: LensPrime<RcBrand, User, Address> = LensPrime::from_view_set(
		|u: User| u.address.clone(),
		|(_, a)| User {
			address: a,
		},
	);

	let street_prism: PrismPrime<RcBrand, Address, String> = PrismPrime::from_option(
		|a: Address| Some(a.street.clone()),
		|s| Address {
			street: s,
		},
	);

	let user_street = optics_compose(address_lens, street_prism);
	let user = User {
		address: Address {
			street: "High St".to_string(),
		},
	};

	let street = optics_preview::<RcBrand, _, _>(&user_street, user);
	assert_eq!(street, Some("High St".to_string()));
}