mod serde {
    use serde::{Deserialize, Serialize};
    use serde_dhall::{from_str, serialize, FromDhall, StaticType, ToDhall};

    fn assert_de<T>(s: &str, x: T)
    where
        T: FromDhall + StaticType + PartialEq + std::fmt::Debug,
    {
        assert_eq!(
            from_str(s)
                .static_type_annotation()
                .parse::<T>()
                .map_err(|e| e.to_string()),
            Ok(x)
        );
    }
    fn assert_ser<T>(s: &str, x: T)
    where
        T: ToDhall + StaticType + PartialEq + std::fmt::Debug,
    {
        assert_eq!(
            serialize(&x)
                .static_type_annotation()
                .to_string()
                .map_err(|e| e.to_string()),
            Ok(s.to_string())
        );
    }
    fn assert_serde<T>(s: &str, x: T)
    where
        T: ToDhall
            + FromDhall
            + StaticType
            + PartialEq
            + std::fmt::Debug
            + Clone,
    {
        assert_de(s, x.clone());
        assert_ser(s, x);
    }

    #[test]
    fn numbers() {
        assert_serde("True", true);

        assert_serde("1", 1u64);
        assert_serde("1", 1u32);
        assert_serde("1", 1usize);

        assert_serde("+1", 1i64);
        assert_serde("+1", 1i32);
        assert_serde("+1", 1isize);

        assert_serde("1.0", 1.0f64);
        assert_serde("1.0", 1.0f32);
    }

    #[test]
    fn text() {
        assert_serde(r#""foo""#, "foo".to_owned());
        assert_ser(r#""foo""#, "foo");
    }

    #[test]
    fn list() {
        assert_serde("[] : List Natural", <Vec<u64>>::new());
        assert_serde("[] : List Text", <Vec<String>>::new());
        assert_serde(
            r#"["foo", "bar"]"#,
            vec!["foo".to_owned(), "bar".to_owned()],
        );
        assert_ser(r#"["foo", "bar"]"#, vec!["foo", "bar"]);
        assert_serde::<Vec<u64>>("[1, 2]", vec![1, 2]);
    }

    #[test]
    fn optional() {
        assert_serde("None Natural", None::<u64>);
        assert_serde("None Text", None::<String>);
        assert_serde("Some 1", Some(1u64));
        assert_eq!(
            serialize(&None::<u64>).to_string().map_err(|e| e.to_string()),
            Err("cannot serialize value without a type annotation: Optional(None)".to_string())
        );
    }

    #[test]
    fn tuple() {
        assert_serde::<()>(r#"{=}"#, ());
        assert_serde::<(u64, String)>(
            r#"{ _1 = 1, _2 = "foo" }"#,
            (1, "foo".to_owned()),
        );
        assert_serde::<(u64, u64, u64, u64)>(
            r#"{ _1 = 1, _2 = 2, _3 = 3, _4 = 4 }"#,
            (1, 2, 3, 4),
        );
    }

    #[test]
    fn structs() {
        // #[derive(
        //     Debug, Clone, PartialEq, Eq, Deserialize, Serialize, StaticType,
        // )]
        // struct Foo;
        // assert_serde::<Foo>("{=}", Foo);

        // #[derive(
        //     Debug, Clone, PartialEq, Eq, Deserialize, Serialize, StaticType,
        // )]
        // struct Bar(u64);
        // assert_serde::<Bar>("{ _1 = 1 }", Bar (1));

        #[derive(
            Debug, Clone, PartialEq, Eq, Deserialize, Serialize, StaticType,
        )]
        struct Baz {
            x: u64,
            y: i64,
        }
        assert_serde::<Baz>("{ x = 1, y = -2 }", Baz { x: 1, y: -2 });
    }

    #[test]
    fn enums() {
        #[derive(
            Debug, Clone, PartialEq, Eq, Deserialize, Serialize, StaticType,
        )]
        enum Foo {
            X(u64),
            Y(i64),
        }
        assert_serde::<Foo>("< X: Natural | Y: Integer >.X 1", Foo::X(1));

        #[derive(
            Debug, Clone, PartialEq, Eq, Deserialize, Serialize, StaticType,
        )]
        enum Bar {
            X,
            Y(i64),
        }
        assert_serde::<Bar>("< X | Y: Integer >.X", Bar::X);

        assert!(from_str("< X | Y: Integer >.Y")
            .static_type_annotation()
            .parse::<Bar>()
            .is_err());
    }

    #[test]
    fn test_de_untyped() {
        use std::collections::BTreeMap;
        use std::collections::HashMap;

        fn parse<T: FromDhall>(s: &str) -> T {
            from_str(s).parse().unwrap()
        }

        // Test tuples on record of wrong type. Fields are just taken in alphabetic order.
        assert_eq!(
            parse::<(u64, String, i64)>(r#"{ y = "foo", x = 1, z = +42 }"#),
            (1, "foo".to_owned(), 42)
        );

        let mut expected_map = HashMap::new();
        expected_map.insert("x".to_string(), 1);
        expected_map.insert("y".to_string(), 2);
        assert_eq!(
            parse::<HashMap<String, u64>>("{ x = 1, y = 2 }"),
            expected_map
        );
        assert_eq!(
            parse::<HashMap<String, u64>>("toMap { x = 1, y = 2 }"),
            expected_map
        );

        let mut expected_map = HashMap::new();
        expected_map.insert("if".to_string(), 1);
        expected_map.insert("FOO_BAR".to_string(), 2);
        expected_map.insert("baz-kux".to_string(), 3);
        assert_eq!(
            parse::<HashMap<String, u64>>(
                "{ `if` = 1, FOO_BAR = 2, baz-kux = 3 }"
            ),
            expected_map
        );

        let mut expected_map = BTreeMap::new();
        expected_map.insert("x".to_string(), 1);
        expected_map.insert("y".to_string(), 2);
        assert_eq!(
            parse::<BTreeMap<String, u64>>("{ x = 1, y = 2 }"),
            expected_map
        );

        #[derive(Debug, PartialEq, Eq, Deserialize)]
        struct Foo {
            x: u64,
            y: Option<u64>,
        }
        // Omit optional field
        assert_eq!(parse::<Foo>("{ x = 1 }"), Foo { x: 1, y: None });

        // https://github.com/Nadrieril/dhall-rust/issues/155
        assert!(from_str("List/length [True, 42]").parse::<bool>().is_err());
    }

    // TODO: test various builder configurations
    // In particular test cloning and reusing builder
}