use serde::Deserialize;

#[derive(Debug, Deserialize, PartialEq)]
struct OuterStruct {
    inner: TheEnum,
}

#[derive(Debug, Deserialize, PartialEq)]
enum TheEnum {
    Plain,
    Tuple(i64, bool),
    NewType(String),
    Struct { value: i64 },
}

#[derive(Debug, Deserialize, PartialEq)]
struct Val {
    val: TheEnum,
}

#[derive(Debug, Deserialize, PartialEq)]
struct Multi {
    enums: Vec<TheEnum>,
}

fn value_from_str<T>(s: &'_ str) -> Result<T, toml::de::Error>
where
    T: serde::de::DeserializeOwned,
{
    T::deserialize(toml::de::ValueDeserializer::new(s))
}

#[test]
fn invalid_variant_returns_error_with_good_message_string() {
    let error = value_from_str::<TheEnum>("\"NonExistent\"").unwrap_err();
    snapbox::assert_eq(
        r#"unknown variant `NonExistent`, expected one of `Plain`, `Tuple`, `NewType`, `Struct`
"#,
        error.to_string(),
    );

    let error = toml::from_str::<Val>("val = \"NonExistent\"").unwrap_err();
    snapbox::assert_eq(
        r#"TOML parse error at line 1, column 7
  |
1 | val = "NonExistent"
  |       ^^^^^^^^^^^^^
unknown variant `NonExistent`, expected one of `Plain`, `Tuple`, `NewType`, `Struct`
"#,
        error.to_string(),
    );
}

#[test]
fn invalid_variant_returns_error_with_good_message_inline_table() {
    let error = value_from_str::<TheEnum>("{ NonExistent = {} }").unwrap_err();
    snapbox::assert_eq(
        r#"unknown variant `NonExistent`, expected one of `Plain`, `Tuple`, `NewType`, `Struct`
"#,
        error.to_string(),
    );

    let error = toml::from_str::<Val>("val = { NonExistent = {} }").unwrap_err();
    snapbox::assert_eq(
        r#"TOML parse error at line 1, column 9
  |
1 | val = { NonExistent = {} }
  |         ^^^^^^^^^^^
unknown variant `NonExistent`, expected one of `Plain`, `Tuple`, `NewType`, `Struct`
"#,
        error.to_string(),
    );
}

#[test]
fn extra_field_returns_expected_empty_table_error() {
    let error = value_from_str::<TheEnum>("{ Plain = { extra_field = 404 } }").unwrap_err();
    snapbox::assert_eq(
        r#"expected empty table
"#,
        error.to_string(),
    );

    let error = toml::from_str::<Val>("val = { Plain = { extra_field = 404 } }").unwrap_err();
    snapbox::assert_eq(
        r#"TOML parse error at line 1, column 17
  |
1 | val = { Plain = { extra_field = 404 } }
  |                 ^^^^^^^^^^^^^^^^^^^^^
expected empty table
"#,
        error.to_string(),
    );
}

#[test]
fn extra_field_returns_expected_empty_table_error_struct_variant() {
    let error = value_from_str::<TheEnum>("{ Struct = { value = 123, extra_0 = 0, extra_1 = 1 } }")
        .unwrap_err();

    snapbox::assert_eq(
        r#"unexpected keys in table: extra_0, extra_1, available keys: value
"#,
        error.to_string(),
    );

    let error =
        toml::from_str::<Val>("val = { Struct = { value = 123, extra_0 = 0, extra_1 = 1 } }")
            .unwrap_err();

    snapbox::assert_eq(
        r#"TOML parse error at line 1, column 33
  |
1 | val = { Struct = { value = 123, extra_0 = 0, extra_1 = 1 } }
  |                                 ^^^^^^^
unexpected keys in table: extra_0, extra_1, available keys: value
"#,
        error.to_string(),
    );
}

mod enum_unit {
    use super::*;

    #[test]
    fn from_str() {
        assert_eq!(TheEnum::Plain, value_from_str("\"Plain\"").unwrap());

        assert_eq!(
            Val {
                val: TheEnum::Plain
            },
            toml::from_str("val = \"Plain\"").unwrap()
        );
    }

    #[test]
    fn from_inline_table() {
        assert_eq!(TheEnum::Plain, value_from_str("{ Plain = {} }").unwrap());
        assert_eq!(
            Val {
                val: TheEnum::Plain
            },
            toml::from_str("val = { Plain = {} }").unwrap()
        );
    }

    #[test]
    fn from_std_table() {
        assert_eq!(TheEnum::Plain, toml::from_str("[Plain]\n").unwrap());
    }
}

mod enum_tuple {
    use super::*;

    #[test]
    fn from_inline_table() {
        assert_eq!(
            TheEnum::Tuple(-123, true),
            value_from_str("{ Tuple = { 0 = -123, 1 = true } }").unwrap()
        );
        assert_eq!(
            Val {
                val: TheEnum::Tuple(-123, true)
            },
            toml::from_str("val = { Tuple = { 0 = -123, 1 = true } }").unwrap()
        );
    }

    #[test]
    fn from_std_table() {
        assert_eq!(
            TheEnum::Tuple(-123, true),
            toml::from_str(
                r#"[Tuple]
                0 = -123
                1 = true
                "#
            )
            .unwrap()
        );
    }
}

mod enum_newtype {
    use super::*;

    #[test]
    fn from_inline_table() {
        assert_eq!(
            TheEnum::NewType("value".to_string()),
            value_from_str(r#"{ NewType = "value" }"#).unwrap()
        );
        assert_eq!(
            Val {
                val: TheEnum::NewType("value".to_string()),
            },
            toml::from_str(r#"val = { NewType = "value" }"#).unwrap()
        );
    }

    #[test]
    fn from_std_table() {
        assert_eq!(
            TheEnum::NewType("value".to_string()),
            toml::from_str(r#"NewType = "value""#).unwrap()
        );
        assert_eq!(
            Val {
                val: TheEnum::NewType("value".to_string()),
            },
            toml::from_str(
                r#"[val]
                NewType = "value"
                "#
            )
            .unwrap()
        );
    }
}

mod enum_struct {
    use super::*;

    #[test]
    fn from_inline_table() {
        assert_eq!(
            TheEnum::Struct { value: -123 },
            value_from_str("{ Struct = { value = -123 } }").unwrap()
        );
        assert_eq!(
            Val {
                val: TheEnum::Struct { value: -123 }
            },
            toml::from_str("val = { Struct = { value = -123 } }").unwrap()
        );
    }

    #[test]
    fn from_std_table() {
        assert_eq!(
            TheEnum::Struct { value: -123 },
            toml::from_str(
                r#"[Struct]
                value = -123
                "#
            )
            .unwrap()
        );
    }

    #[test]
    fn from_nested_std_table() {
        assert_eq!(
            OuterStruct {
                inner: TheEnum::Struct { value: -123 }
            },
            toml::from_str(
                r#"[inner.Struct]
                value = -123
                "#
            )
            .unwrap()
        );
    }
}

mod enum_array {
    use super::*;

    #[test]
    fn from_inline_tables() {
        let toml_str = r#"
            enums = [
                { Plain = {} },
                { Tuple = { 0 = -123, 1 = true } },
                { NewType = "value" },
                { Struct = { value = -123 } }
            ]"#;
        assert_eq!(
            Multi {
                enums: vec![
                    TheEnum::Plain,
                    TheEnum::Tuple(-123, true),
                    TheEnum::NewType("value".to_string()),
                    TheEnum::Struct { value: -123 },
                ]
            },
            toml::from_str(toml_str).unwrap()
        );
    }

    #[test]
    fn from_std_table() {
        let toml_str = r#"[[enums]]
            Plain = {}

            [[enums]]
            Tuple = { 0 = -123, 1 = true }

            [[enums]]
            NewType = "value"

            [[enums]]
            Struct = { value = -123 }
            "#;
        assert_eq!(
            Multi {
                enums: vec![
                    TheEnum::Plain,
                    TheEnum::Tuple(-123, true),
                    TheEnum::NewType("value".to_string()),
                    TheEnum::Struct { value: -123 },
                ]
            },
            toml::from_str(toml_str).unwrap()
        );
    }
}
