//! Extractor that will get captures from the URL and parse them using
//! [`serde`].

mod de;

use crate::{
    extract::{rejection::*, FromRequestParts},
    routing::url_params::UrlParams,
    util::PercentDecodedStr,
};
use async_trait::async_trait;
use axum_core::response::{IntoResponse, Response};
use http::{request::Parts, StatusCode};
use serde::de::DeserializeOwned;
use std::{fmt, sync::Arc};

/// Extractor that will get captures from the URL and parse them using
/// [`serde`].
///
/// Any percent encoded parameters will be automatically decoded. The decoded
/// parameters must be valid UTF-8, otherwise `Path` will fail and return a `400
/// Bad Request` response.
///
/// # Example
///
/// These examples assume the `serde` feature of the [`uuid`] crate is enabled.
///
/// [`uuid`]: https://crates.io/crates/uuid
///
/// ```rust,no_run
/// use axum::{
///     extract::Path,
///     routing::get,
///     Router,
/// };
/// use uuid::Uuid;
///
/// async fn users_teams_show(
///     Path((user_id, team_id)): Path<(Uuid, Uuid)>,
/// ) {
///     // ...
/// }
///
/// let app = Router::new().route("/users/:user_id/team/:team_id", get(users_teams_show));
/// # async {
/// # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
/// # };
/// ```
///
/// If the path contains only one parameter, then you can omit the tuple.
///
/// ```rust,no_run
/// use axum::{
///     extract::Path,
///     routing::get,
///     Router,
/// };
/// use uuid::Uuid;
///
/// async fn user_info(Path(user_id): Path<Uuid>) {
///     // ...
/// }
///
/// let app = Router::new().route("/users/:user_id", get(user_info));
/// # async {
/// # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
/// # };
/// ```
///
/// Path segments also can be deserialized into any type that implements
/// [`serde::Deserialize`]. This includes tuples and structs:
///
/// ```rust,no_run
/// use axum::{
///     extract::Path,
///     routing::get,
///     Router,
/// };
/// use serde::Deserialize;
/// use uuid::Uuid;
///
/// // Path segment labels will be matched with struct field names
/// #[derive(Deserialize)]
/// struct Params {
///     user_id: Uuid,
///     team_id: Uuid,
/// }
///
/// async fn users_teams_show(
///     Path(Params { user_id, team_id }): Path<Params>,
/// ) {
///     // ...
/// }
///
/// // When using tuples the path segments will be matched by their position in the route
/// async fn users_teams_create(
///     Path((user_id, team_id)): Path<(String, String)>,
/// ) {
///     // ...
/// }
///
/// let app = Router::new().route(
///     "/users/:user_id/team/:team_id",
///     get(users_teams_show).post(users_teams_create),
/// );
/// # async {
/// # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
/// # };
/// ```
///
/// If you wish to capture all path parameters you can use `HashMap` or `Vec`:
///
/// ```rust,no_run
/// use axum::{
///     extract::Path,
///     routing::get,
///     Router,
/// };
/// use std::collections::HashMap;
///
/// async fn params_map(
///     Path(params): Path<HashMap<String, String>>,
/// ) {
///     // ...
/// }
///
/// async fn params_vec(
///     Path(params): Path<Vec<(String, String)>>,
/// ) {
///     // ...
/// }
///
/// let app = Router::new()
///     .route("/users/:user_id/team/:team_id", get(params_map).post(params_vec));
/// # async {
/// # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
/// # };
/// ```
///
/// # Providing detailed rejection output
///
/// If the URI cannot be deserialized into the target type the request will be rejected and an
/// error response will be returned. See [`customize-path-rejection`] for an example of how to customize that error.
///
/// [`serde`]: https://crates.io/crates/serde
/// [`serde::Deserialize`]: https://docs.rs/serde/1.0.127/serde/trait.Deserialize.html
/// [`customize-path-rejection`]: https://github.com/tokio-rs/axum/blob/main/examples/customize-path-rejection/src/main.rs
#[derive(Debug)]
pub struct Path<T>(pub T);

axum_core::__impl_deref!(Path);

#[async_trait]
impl<T, S> FromRequestParts<S> for Path<T>
where
    T: DeserializeOwned + Send,
    S: Send + Sync,
{
    type Rejection = PathRejection;

    async fn from_request_parts(parts: &mut Parts, _state: &S) -> Result<Self, Self::Rejection> {
        let params = match parts.extensions.get::<UrlParams>() {
            Some(UrlParams::Params(params)) => params,
            Some(UrlParams::InvalidUtf8InPathParam { key }) => {
                let err = PathDeserializationError {
                    kind: ErrorKind::InvalidUtf8InPathParam {
                        key: key.to_string(),
                    },
                };
                let err = FailedToDeserializePathParams(err);
                return Err(err.into());
            }
            None => {
                return Err(MissingPathParams.into());
            }
        };

        T::deserialize(de::PathDeserializer::new(params))
            .map_err(|err| {
                PathRejection::FailedToDeserializePathParams(FailedToDeserializePathParams(err))
            })
            .map(Path)
    }
}

// this wrapper type is used as the deserializer error to hide the `serde::de::Error` impl which
// would otherwise be public if we used `ErrorKind` as the error directly
#[derive(Debug)]
pub(crate) struct PathDeserializationError {
    pub(super) kind: ErrorKind,
}

impl PathDeserializationError {
    pub(super) fn new(kind: ErrorKind) -> Self {
        Self { kind }
    }

    pub(super) fn wrong_number_of_parameters() -> WrongNumberOfParameters<()> {
        WrongNumberOfParameters { got: () }
    }

    #[track_caller]
    pub(super) fn unsupported_type(name: &'static str) -> Self {
        Self::new(ErrorKind::UnsupportedType { name })
    }
}

pub(super) struct WrongNumberOfParameters<G> {
    got: G,
}

impl<G> WrongNumberOfParameters<G> {
    #[allow(clippy::unused_self)]
    pub(super) fn got<G2>(self, got: G2) -> WrongNumberOfParameters<G2> {
        WrongNumberOfParameters { got }
    }
}

impl WrongNumberOfParameters<usize> {
    pub(super) fn expected(self, expected: usize) -> PathDeserializationError {
        PathDeserializationError::new(ErrorKind::WrongNumberOfParameters {
            got: self.got,
            expected,
        })
    }
}

impl serde::de::Error for PathDeserializationError {
    #[inline]
    fn custom<T>(msg: T) -> Self
    where
        T: fmt::Display,
    {
        Self {
            kind: ErrorKind::Message(msg.to_string()),
        }
    }
}

impl fmt::Display for PathDeserializationError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.kind.fmt(f)
    }
}

impl std::error::Error for PathDeserializationError {}

/// The kinds of errors that can happen we deserializing into a [`Path`].
///
/// This type is obtained through [`FailedToDeserializePathParams::kind`] or
/// [`FailedToDeserializePathParams::into_kind`] and is useful for building
/// more precise error messages.
#[derive(Debug, PartialEq, Eq)]
#[non_exhaustive]
pub enum ErrorKind {
    /// The URI contained the wrong number of parameters.
    WrongNumberOfParameters {
        /// The number of actual parameters in the URI.
        got: usize,
        /// The number of expected parameters.
        expected: usize,
    },

    /// Failed to parse the value at a specific key into the expected type.
    ///
    /// This variant is used when deserializing into types that have named fields, such as structs.
    ParseErrorAtKey {
        /// The key at which the value was located.
        key: String,
        /// The value from the URI.
        value: String,
        /// The expected type of the value.
        expected_type: &'static str,
    },

    /// Failed to parse the value at a specific index into the expected type.
    ///
    /// This variant is used when deserializing into sequence types, such as tuples.
    ParseErrorAtIndex {
        /// The index at which the value was located.
        index: usize,
        /// The value from the URI.
        value: String,
        /// The expected type of the value.
        expected_type: &'static str,
    },

    /// Failed to parse a value into the expected type.
    ///
    /// This variant is used when deserializing into a primitive type (such as `String` and `u32`).
    ParseError {
        /// The value from the URI.
        value: String,
        /// The expected type of the value.
        expected_type: &'static str,
    },

    /// A parameter contained text that, once percent decoded, wasn't valid UTF-8.
    InvalidUtf8InPathParam {
        /// The key at which the invalid value was located.
        key: String,
    },

    /// Tried to serialize into an unsupported type such as nested maps.
    ///
    /// This error kind is caused by programmer errors and thus gets converted into a `500 Internal
    /// Server Error` response.
    UnsupportedType {
        /// The name of the unsupported type.
        name: &'static str,
    },

    /// Catch-all variant for errors that don't fit any other variant.
    Message(String),
}

impl fmt::Display for ErrorKind {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ErrorKind::Message(error) => error.fmt(f),
            ErrorKind::InvalidUtf8InPathParam { key } => write!(f, "Invalid UTF-8 in `{key}`"),
            ErrorKind::WrongNumberOfParameters { got, expected } => {
                write!(
                    f,
                    "Wrong number of path arguments for `Path`. Expected {expected} but got {got}"
                )?;

                if *expected == 1 {
                    write!(f, ". Note that multiple parameters must be extracted with a tuple `Path<(_, _)>` or a struct `Path<YourParams>`")?;
                }

                Ok(())
            }
            ErrorKind::UnsupportedType { name } => write!(f, "Unsupported type `{name}`"),
            ErrorKind::ParseErrorAtKey {
                key,
                value,
                expected_type,
            } => write!(
                f,
                "Cannot parse `{key}` with value `{value:?}` to a `{expected_type}`"
            ),
            ErrorKind::ParseError {
                value,
                expected_type,
            } => write!(f, "Cannot parse `{value:?}` to a `{expected_type}`"),
            ErrorKind::ParseErrorAtIndex {
                index,
                value,
                expected_type,
            } => write!(
                f,
                "Cannot parse value at index {index} with value `{value:?}` to a `{expected_type}`"
            ),
        }
    }
}

/// Rejection type for [`Path`](super::Path) if the captured routes params couldn't be deserialized
/// into the expected type.
#[derive(Debug)]
pub struct FailedToDeserializePathParams(PathDeserializationError);

impl FailedToDeserializePathParams {
    /// Get a reference to the underlying error kind.
    pub fn kind(&self) -> &ErrorKind {
        &self.0.kind
    }

    /// Convert this error into the underlying error kind.
    pub fn into_kind(self) -> ErrorKind {
        self.0.kind
    }

    /// Get the response body text used for this rejection.
    pub fn body_text(&self) -> String {
        match self.0.kind {
            ErrorKind::Message(_)
            | ErrorKind::InvalidUtf8InPathParam { .. }
            | ErrorKind::ParseError { .. }
            | ErrorKind::ParseErrorAtIndex { .. }
            | ErrorKind::ParseErrorAtKey { .. } => format!("Invalid URL: {}", self.0.kind),
            ErrorKind::WrongNumberOfParameters { .. } | ErrorKind::UnsupportedType { .. } => {
                self.0.kind.to_string()
            }
        }
    }

    /// Get the status code used for this rejection.
    pub fn status(&self) -> StatusCode {
        match self.0.kind {
            ErrorKind::Message(_)
            | ErrorKind::InvalidUtf8InPathParam { .. }
            | ErrorKind::ParseError { .. }
            | ErrorKind::ParseErrorAtIndex { .. }
            | ErrorKind::ParseErrorAtKey { .. } => StatusCode::BAD_REQUEST,
            ErrorKind::WrongNumberOfParameters { .. } | ErrorKind::UnsupportedType { .. } => {
                StatusCode::INTERNAL_SERVER_ERROR
            }
        }
    }
}

impl IntoResponse for FailedToDeserializePathParams {
    fn into_response(self) -> Response {
        axum_core::__log_rejection!(
            rejection_type = Self,
            body_text = self.body_text(),
            status = self.status(),
        );
        (self.status(), self.body_text()).into_response()
    }
}

impl fmt::Display for FailedToDeserializePathParams {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.0.fmt(f)
    }
}

impl std::error::Error for FailedToDeserializePathParams {}

/// Extractor that will get captures from the URL without deserializing them.
///
/// In general you should prefer to use [`Path`] as it is higher level, however `RawPathParams` is
/// suitable if just want the raw params without deserializing them and thus saving some
/// allocations.
///
/// Any percent encoded parameters will be automatically decoded. The decoded parameters must be
/// valid UTF-8, otherwise `RawPathParams` will fail and return a `400 Bad Request` response.
///
/// # Example
///
/// ```rust,no_run
/// use axum::{
///     extract::RawPathParams,
///     routing::get,
///     Router,
/// };
///
/// async fn users_teams_show(params: RawPathParams) {
///     for (key, value) in &params {
///         println!("{key:?} = {value:?}");
///     }
/// }
///
/// let app = Router::new().route("/users/:user_id/team/:team_id", get(users_teams_show));
/// # let _: Router = app;
/// ```
#[derive(Debug)]
pub struct RawPathParams(Vec<(Arc<str>, PercentDecodedStr)>);

#[async_trait]
impl<S> FromRequestParts<S> for RawPathParams
where
    S: Send + Sync,
{
    type Rejection = RawPathParamsRejection;

    async fn from_request_parts(parts: &mut Parts, _state: &S) -> Result<Self, Self::Rejection> {
        let params = match parts.extensions.get::<UrlParams>() {
            Some(UrlParams::Params(params)) => params,
            Some(UrlParams::InvalidUtf8InPathParam { key }) => {
                return Err(InvalidUtf8InPathParam {
                    key: Arc::clone(key),
                }
                .into());
            }
            None => {
                return Err(MissingPathParams.into());
            }
        };

        Ok(Self(params.clone()))
    }
}

impl RawPathParams {
    /// Get an iterator over the path parameters.
    pub fn iter(&self) -> RawPathParamsIter<'_> {
        self.into_iter()
    }
}

impl<'a> IntoIterator for &'a RawPathParams {
    type Item = (&'a str, &'a str);
    type IntoIter = RawPathParamsIter<'a>;

    fn into_iter(self) -> Self::IntoIter {
        RawPathParamsIter(self.0.iter())
    }
}

/// An iterator over raw path parameters.
///
/// Created with [`RawPathParams::iter`].
#[derive(Debug)]
pub struct RawPathParamsIter<'a>(std::slice::Iter<'a, (Arc<str>, PercentDecodedStr)>);

impl<'a> Iterator for RawPathParamsIter<'a> {
    type Item = (&'a str, &'a str);

    fn next(&mut self) -> Option<Self::Item> {
        let (key, value) = self.0.next()?;
        Some((&**key, value.as_str()))
    }
}

/// Rejection used by [`RawPathParams`] if a parameter contained text that, once percent decoded,
/// wasn't valid UTF-8.
#[derive(Debug)]
pub struct InvalidUtf8InPathParam {
    key: Arc<str>,
}

impl InvalidUtf8InPathParam {
    /// Get the response body text used for this rejection.
    pub fn body_text(&self) -> String {
        self.to_string()
    }

    /// Get the status code used for this rejection.
    pub fn status(&self) -> StatusCode {
        StatusCode::BAD_REQUEST
    }
}

impl fmt::Display for InvalidUtf8InPathParam {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "Invalid UTF-8 in `{}`", self.key)
    }
}

impl std::error::Error for InvalidUtf8InPathParam {}

impl IntoResponse for InvalidUtf8InPathParam {
    fn into_response(self) -> Response {
        (self.status(), self.body_text()).into_response()
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{routing::get, test_helpers::*, Router};
    use http::StatusCode;
    use serde::Deserialize;
    use std::collections::HashMap;

    #[crate::test]
    async fn extracting_url_params() {
        let app = Router::new().route(
            "/users/:id",
            get(|Path(id): Path<i32>| async move {
                assert_eq!(id, 42);
            })
            .post(|Path(params_map): Path<HashMap<String, i32>>| async move {
                assert_eq!(params_map.get("id").unwrap(), &1337);
            }),
        );

        let client = TestClient::new(app);

        let res = client.get("/users/42").send().await;
        assert_eq!(res.status(), StatusCode::OK);

        let res = client.post("/users/1337").send().await;
        assert_eq!(res.status(), StatusCode::OK);
    }

    #[crate::test]
    async fn extracting_url_params_multiple_times() {
        let app = Router::new().route("/users/:id", get(|_: Path<i32>, _: Path<String>| async {}));

        let client = TestClient::new(app);

        let res = client.get("/users/42").send().await;
        assert_eq!(res.status(), StatusCode::OK);
    }

    #[crate::test]
    async fn percent_decoding() {
        let app = Router::new().route(
            "/:key",
            get(|Path(param): Path<String>| async move { param }),
        );

        let client = TestClient::new(app);

        let res = client.get("/one%20two").send().await;

        assert_eq!(res.text().await, "one two");
    }

    #[crate::test]
    async fn supports_128_bit_numbers() {
        let app = Router::new()
            .route(
                "/i/:key",
                get(|Path(param): Path<i128>| async move { param.to_string() }),
            )
            .route(
                "/u/:key",
                get(|Path(param): Path<u128>| async move { param.to_string() }),
            );

        let client = TestClient::new(app);

        let res = client.get("/i/123").send().await;
        assert_eq!(res.text().await, "123");

        let res = client.get("/u/123").send().await;
        assert_eq!(res.text().await, "123");
    }

    #[crate::test]
    async fn wildcard() {
        let app = Router::new()
            .route(
                "/foo/*rest",
                get(|Path(param): Path<String>| async move { param }),
            )
            .route(
                "/bar/*rest",
                get(|Path(params): Path<HashMap<String, String>>| async move {
                    params.get("rest").unwrap().clone()
                }),
            );

        let client = TestClient::new(app);

        let res = client.get("/foo/bar/baz").send().await;
        assert_eq!(res.text().await, "bar/baz");

        let res = client.get("/bar/baz/qux").send().await;
        assert_eq!(res.text().await, "baz/qux");
    }

    #[crate::test]
    async fn captures_dont_match_empty_segments() {
        let app = Router::new().route("/:key", get(|| async {}));

        let client = TestClient::new(app);

        let res = client.get("/").send().await;
        assert_eq!(res.status(), StatusCode::NOT_FOUND);

        let res = client.get("/foo").send().await;
        assert_eq!(res.status(), StatusCode::OK);
    }

    #[crate::test]
    async fn str_reference_deserialize() {
        struct Param(String);
        impl<'de> serde::Deserialize<'de> for Param {
            fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
            where
                D: serde::Deserializer<'de>,
            {
                let s = <&str as serde::Deserialize>::deserialize(deserializer)?;
                Ok(Param(s.to_owned()))
            }
        }

        let app = Router::new().route("/:key", get(|param: Path<Param>| async move { param.0 .0 }));

        let client = TestClient::new(app);

        let res = client.get("/foo").send().await;
        assert_eq!(res.text().await, "foo");

        // percent decoding should also work
        let res = client.get("/foo%20bar").send().await;
        assert_eq!(res.text().await, "foo bar");
    }

    #[crate::test]
    async fn two_path_extractors() {
        let app = Router::new().route("/:a/:b", get(|_: Path<String>, _: Path<String>| async {}));

        let client = TestClient::new(app);

        let res = client.get("/a/b").send().await;
        assert_eq!(res.status(), StatusCode::INTERNAL_SERVER_ERROR);
        assert_eq!(
            res.text().await,
            "Wrong number of path arguments for `Path`. Expected 1 but got 2. \
            Note that multiple parameters must be extracted with a tuple `Path<(_, _)>` or a struct `Path<YourParams>`",
        );
    }

    #[crate::test]
    async fn deserialize_into_vec_of_tuples() {
        let app = Router::new().route(
            "/:a/:b",
            get(|Path(params): Path<Vec<(String, String)>>| async move {
                assert_eq!(
                    params,
                    vec![
                        ("a".to_owned(), "foo".to_owned()),
                        ("b".to_owned(), "bar".to_owned())
                    ]
                );
            }),
        );

        let client = TestClient::new(app);

        let res = client.get("/foo/bar").send().await;
        assert_eq!(res.status(), StatusCode::OK);
    }

    #[crate::test]
    async fn type_that_uses_deserialize_any() {
        use time::Date;

        #[derive(Deserialize)]
        struct Params {
            a: Date,
            b: Date,
            c: Date,
        }

        let app = Router::new()
            .route(
                "/single/:a",
                get(|Path(a): Path<Date>| async move { format!("single: {a}") }),
            )
            .route(
                "/tuple/:a/:b/:c",
                get(|Path((a, b, c)): Path<(Date, Date, Date)>| async move {
                    format!("tuple: {a} {b} {c}")
                }),
            )
            .route(
                "/vec/:a/:b/:c",
                get(|Path(vec): Path<Vec<Date>>| async move {
                    let [a, b, c]: [Date; 3] = vec.try_into().unwrap();
                    format!("vec: {a} {b} {c}")
                }),
            )
            .route(
                "/vec_pairs/:a/:b/:c",
                get(|Path(vec): Path<Vec<(String, Date)>>| async move {
                    let [(_, a), (_, b), (_, c)]: [(String, Date); 3] = vec.try_into().unwrap();
                    format!("vec_pairs: {a} {b} {c}")
                }),
            )
            .route(
                "/map/:a/:b/:c",
                get(|Path(mut map): Path<HashMap<String, Date>>| async move {
                    let a = map.remove("a").unwrap();
                    let b = map.remove("b").unwrap();
                    let c = map.remove("c").unwrap();
                    format!("map: {a} {b} {c}")
                }),
            )
            .route(
                "/struct/:a/:b/:c",
                get(|Path(params): Path<Params>| async move {
                    format!("struct: {} {} {}", params.a, params.b, params.c)
                }),
            );

        let client = TestClient::new(app);

        let res = client.get("/single/2023-01-01").send().await;
        assert_eq!(res.text().await, "single: 2023-01-01");

        let res = client
            .get("/tuple/2023-01-01/2023-01-02/2023-01-03")
            .send()
            .await;
        assert_eq!(res.text().await, "tuple: 2023-01-01 2023-01-02 2023-01-03");

        let res = client
            .get("/vec/2023-01-01/2023-01-02/2023-01-03")
            .send()
            .await;
        assert_eq!(res.text().await, "vec: 2023-01-01 2023-01-02 2023-01-03");

        let res = client
            .get("/vec_pairs/2023-01-01/2023-01-02/2023-01-03")
            .send()
            .await;
        assert_eq!(
            res.text().await,
            "vec_pairs: 2023-01-01 2023-01-02 2023-01-03",
        );

        let res = client
            .get("/map/2023-01-01/2023-01-02/2023-01-03")
            .send()
            .await;
        assert_eq!(res.text().await, "map: 2023-01-01 2023-01-02 2023-01-03");

        let res = client
            .get("/struct/2023-01-01/2023-01-02/2023-01-03")
            .send()
            .await;
        assert_eq!(res.text().await, "struct: 2023-01-01 2023-01-02 2023-01-03");
    }

    #[crate::test]
    async fn wrong_number_of_parameters_json() {
        use serde_json::Value;

        let app = Router::new()
            .route("/one/:a", get(|_: Path<(Value, Value)>| async {}))
            .route("/two/:a/:b", get(|_: Path<Value>| async {}));

        let client = TestClient::new(app);

        let res = client.get("/one/1").send().await;
        assert!(res
            .text()
            .await
            .starts_with("Wrong number of path arguments for `Path`. Expected 2 but got 1"));

        let res = client.get("/two/1/2").send().await;
        assert!(res
            .text()
            .await
            .starts_with("Wrong number of path arguments for `Path`. Expected 1 but got 2"));
    }

    #[crate::test]
    async fn raw_path_params() {
        let app = Router::new().route(
            "/:a/:b/:c",
            get(|params: RawPathParams| async move {
                params
                    .into_iter()
                    .map(|(key, value)| format!("{key}={value}"))
                    .collect::<Vec<_>>()
                    .join(" ")
            }),
        );

        let client = TestClient::new(app);
        let res = client.get("/foo/bar/baz").send().await;
        let body = res.text().await;
        assert_eq!(body, "a=foo b=bar c=baz");
    }
}