satay-runtime 0.1.0

#![forbid(unsafe_code)]

use std::fmt;
use std::str::FromStr;

use http::header::{self, CONTENT_TYPE, HeaderName, HeaderValue};
#[cfg(feature = "json")]
use serde::de;
use time::Month;
use time::format_description::well_known::Rfc3339;
pub use time::{Date, OffsetDateTime, PrimitiveDateTime, Time};

use tracing::{debug, instrument};

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct RequestParts<B> {
    pub method: http::Method,
    pub uri: String,
    pub headers: http::HeaderMap,
    pub body: B,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ResponseParts<B> {
    pub status: http::StatusCode,
    pub headers: http::HeaderMap,
    pub body: B,
}

#[derive(Debug, thiserror::Error)]
pub enum Error {
    #[error("failed to build HTTP message: {0}")]
    Http(#[from] http::Error),

    #[error("invalid HTTP header value: {0}")]
    InvalidHeaderValue(#[from] header::InvalidHeaderValue),

    #[error("invalid HTTP header name: {0}")]
    InvalidHeaderName(#[from] header::InvalidHeaderName),

    #[error("missing required field `{0}`")]
    MissingRequired(&'static str),

    #[error("{0}")]
    InvalidResponse(&'static str),

    #[cfg(feature = "json")]
    #[error("JSON error: {0}")]
    Json(#[from] serde_json::Error),
}

#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
pub enum ParseRangeError {
    #[error("range contains more than one `-` separator")]
    TooManySeparators,

    #[error("invalid range minimum `{value}`: {message}")]
    InvalidMinimum { value: String, message: String },

    #[error("invalid range maximum `{value}`: {message}")]
    InvalidMaximum { value: String, message: String },
}

#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
pub enum ParseTimeError {
    #[error("time must be exactly four ASCII digits in HHMM format")]
    InvalidFormat,

    #[error("time is outside valid HHMM range")]
    ComponentRange,
}

#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
pub enum ParseDateError {
    #[error("date must be in YYYY-MM-DD format")]
    InvalidFormat,
}

#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
pub enum ParseNaiveDateTimeError {
    #[error("datetime must be in YYYY-MM-DDTHH:mm:ss format")]
    InvalidFormat,
}

pub trait Action {
    type Response;

    fn request(self) -> Result<http::Request<Vec<u8>>, Error>;
    fn decode<B: AsRef<[u8]>>(response: ResponseParts<B>) -> Result<Self::Response, Error>;
}

#[instrument(skip_all, fields(method = %method, uri = %uri))]
pub fn into_request<B>(
    RequestParts {
        method,
        uri,
        headers,
        body,
    }: RequestParts<B>,
) -> Result<http::Request<B>, Error> {
    debug!("building HTTP request");
    let mut request = http::Request::builder()
        .method(method)
        .uri(uri)
        .body(body)?;
    *request.headers_mut() = headers;
    Ok(request)
}

#[instrument(skip_all, fields(method = %method, uri = %uri))]
pub fn into_empty_request(
    RequestParts {
        method,
        uri,
        headers,
        body: _,
    }: RequestParts<()>,
) -> Result<http::Request<Vec<u8>>, Error> {
    debug!("building empty HTTP request");
    let mut request = http::Request::builder()
        .method(method)
        .uri(uri)
        .body(vec![])?;
    *request.headers_mut() = headers;
    Ok(request)
}

#[cfg(feature = "json")]
#[instrument(skip_all, fields(method = %method, uri = %uri))]
pub fn into_json_request<T>(
    RequestParts {
        method,
        uri,
        headers,
        body,
    }: RequestParts<T>,
) -> Result<http::Request<Vec<u8>>, Error>
where
    T: serde::Serialize,
{
    debug!("building JSON HTTP request");
    let body = serde_json::to_vec(&body)?;
    let mut request = http::Request::builder()
        .method(method)
        .uri(uri)
        .body(body)?;
    *request.headers_mut() = headers;
    if !request.headers().contains_key(CONTENT_TYPE) {
        request.headers_mut().insert(
            CONTENT_TYPE,
            http::HeaderValue::from_static("application/json"),
        );
    }
    Ok(request)
}

#[cfg(feature = "json")]
#[instrument(skip_all, fields(method = %method, uri = %uri))]
pub fn into_optional_json_request<T>(
    RequestParts {
        method,
        uri,
        headers,
        body,
    }: RequestParts<Option<T>>,
) -> Result<http::Request<Vec<u8>>, Error>
where
    T: serde::Serialize,
{
    match body {
        Some(body) => into_json_request(RequestParts {
            method,
            uri,
            headers,
            body,
        }),
        None => into_empty_request(RequestParts {
            method,
            uri,
            headers,
            body: (),
        }),
    }
}

#[cfg(feature = "json")]
#[instrument(skip_all)]
pub fn from_json_slice<T>(body: &[u8]) -> Result<T, Error>
where
    T: de::DeserializeOwned,
{
    debug!("deserializing JSON response");
    Ok(serde_json::from_slice(body)?)
}

pub fn append_path_segment(out: &mut String, value: &str) {
    append_percent_encoded(out, value.as_bytes());
}

pub fn append_query_pair(out: &mut String, first: &mut bool, key: &str, value: &str) {
    if *first {
        out.push('?');
        *first = false;
    } else {
        out.push('&');
    }
    append_percent_encoded(out, key.as_bytes());
    out.push('=');
    append_percent_encoded(out, value.as_bytes());
}

pub fn format_offset_datetime(value: &OffsetDateTime) -> String {
    value.format(&Rfc3339).unwrap_or_else(|_| value.to_string())
}

pub fn format_date(value: &Date) -> String {
    format!(
        "{:04}-{:02}-{:02}",
        value.year(),
        u8::from(value.month()),
        value.day()
    )
}

pub fn parse_date(value: &str) -> Result<Date, ParseDateError> {
    let value = value.trim().as_bytes();
    if value.len() != 10 || value[4] != b'-' || value[7] != b'-' {
        return Err(ParseDateError::InvalidFormat);
    }

    for (index, byte) in value.iter().enumerate() {
        if matches!(index, 4 | 7) {
            if *byte != b'-' {
                return Err(ParseDateError::InvalidFormat);
            }
        } else if !byte.is_ascii_digit() {
            return Err(ParseDateError::InvalidFormat);
        }
    }

    let year = parse_date_year(&value[0..4])?;
    let month = parse_date_u8(&value[5..7])?;
    let day = parse_date_u8(&value[8..10])?;
    let month = Month::try_from(month).map_err(|_| ParseDateError::InvalidFormat)?;
    Date::from_calendar_date(year, month, day).map_err(|_| ParseDateError::InvalidFormat)
}

fn parse_date_year(bytes: &[u8]) -> Result<i32, ParseDateError> {
    let mut value = 0i32;
    for byte in bytes {
        value = value
            .checked_mul(10)
            .and_then(|value| value.checked_add(i32::from(*byte - b'0')))
            .ok_or(ParseDateError::InvalidFormat)?;
    }
    Ok(value)
}

fn parse_date_u8(bytes: &[u8]) -> Result<u8, ParseDateError> {
    let mut value = 0u16;
    for byte in bytes {
        value = value
            .checked_mul(10)
            .and_then(|value| value.checked_add(u16::from(*byte - b'0')))
            .ok_or(ParseDateError::InvalidFormat)?;
    }
    u8::try_from(value).map_err(|_| ParseDateError::InvalidFormat)
}

pub fn format_naive_datetime(value: &PrimitiveDateTime) -> String {
    format!(
        "{}T{:02}:{:02}:{:02}",
        format_date(&value.date()),
        value.hour(),
        value.minute(),
        value.second()
    )
}

pub fn parse_naive_datetime(value: &str) -> Result<PrimitiveDateTime, ParseNaiveDateTimeError> {
    let value = value.trim();
    let bytes = value.as_bytes();
    if bytes.len() != 19
        || bytes[4] != b'-'
        || bytes[7] != b'-'
        || bytes[10] != b'T'
        || bytes[13] != b':'
        || bytes[16] != b':'
    {
        return Err(ParseNaiveDateTimeError::InvalidFormat);
    }

    for (index, byte) in bytes.iter().enumerate() {
        if matches!(index, 4 | 7 | 10 | 13 | 16) {
            continue;
        }
        if !byte.is_ascii_digit() {
            return Err(ParseNaiveDateTimeError::InvalidFormat);
        }
    }

    let date = parse_date(&value[0..10]).map_err(|_| ParseNaiveDateTimeError::InvalidFormat)?;
    let hour = parse_date_u8(&bytes[11..13]).map_err(|_| ParseNaiveDateTimeError::InvalidFormat)?;
    let minute =
        parse_date_u8(&bytes[14..16]).map_err(|_| ParseNaiveDateTimeError::InvalidFormat)?;
    let second =
        parse_date_u8(&bytes[17..19]).map_err(|_| ParseNaiveDateTimeError::InvalidFormat)?;
    let time =
        Time::from_hms(hour, minute, second).map_err(|_| ParseNaiveDateTimeError::InvalidFormat)?;
    Ok(PrimitiveDateTime::new(date, time))
}

pub fn parse_time(value: &str) -> Result<Time, ParseTimeError> {
    let value = value.trim();
    let bytes = value.as_bytes();
    if bytes.len() != 4 || !bytes.iter().all(u8::is_ascii_digit) {
        return Err(ParseTimeError::InvalidFormat);
    }

    let hour = (bytes[0] - b'0') * 10 + (bytes[1] - b'0');
    let minute = (bytes[2] - b'0') * 10 + (bytes[3] - b'0');
    Time::from_hms(hour, minute, 0).map_err(|_| ParseTimeError::ComponentRange)
}

pub fn format_time(value: &Time) -> String {
    format!("{:02}{:02}", value.hour(), value.minute())
}

pub fn format_bool(value: &bool) -> &'static str {
    if *value { "1" } else { "0" }
}

pub fn parse_range<T>(value: &str) -> Result<(Option<T>, Option<T>), ParseRangeError>
where
    T: FromStr,
    T::Err: fmt::Display,
{
    let value = value.trim();
    if value.is_empty() {
        return Ok((None, None));
    }

    let (min, max) = match value.split_once('-') {
        Some((min, max)) => {
            if max.contains('-') {
                return Err(ParseRangeError::TooManySeparators);
            }
            (min, max)
        }
        None => (value, value),
    };

    Ok((parse_range_min(min)?, parse_range_max(max)?))
}

pub fn format_range<T>(min: &Option<T>, max: &Option<T>) -> String
where
    T: fmt::Display,
{
    match (min, max) {
        (Some(min), Some(max)) => format!("{min}-{max}"),
        (Some(min), None) => format!("{min}-"),
        (None, Some(max)) => format!("-{max}"),
        (None, None) => String::new(),
    }
}

fn parse_range_min<T>(value: &str) -> Result<Option<T>, ParseRangeError>
where
    T: FromStr,
    T::Err: fmt::Display,
{
    parse_range_bound(value, |value, message| ParseRangeError::InvalidMinimum {
        value,
        message,
    })
}

fn parse_range_max<T>(value: &str) -> Result<Option<T>, ParseRangeError>
where
    T: FromStr,
    T::Err: fmt::Display,
{
    parse_range_bound(value, |value, message| ParseRangeError::InvalidMaximum {
        value,
        message,
    })
}

fn parse_range_bound<T>(
    value: &str,
    invalid: impl FnOnce(String, String) -> ParseRangeError,
) -> Result<Option<T>, ParseRangeError>
where
    T: FromStr,
    T::Err: fmt::Display,
{
    let value = value.trim();
    if value.is_empty() {
        return Ok(None);
    }

    value
        .parse::<T>()
        .map(Some)
        .map_err(|err| invalid(value.to_owned(), err.to_string()))
}

#[cfg(feature = "serde")]
pub mod serde_string {
    use std::fmt;
    use std::str::FromStr;

    use serde::Deserialize;
    use serde::de::Error as DeError;
    use time::format_description::well_known::Rfc3339;

    use crate::{Date, OffsetDateTime, PrimitiveDateTime, Time};

    macro_rules! string_from_str_module {
        ($module:ident, $ty:ty) => {
            pub mod $module {
                pub fn serialize<S>(value: &$ty, serializer: S) -> Result<S::Ok, S::Error>
                where
                    S: serde::Serializer,
                {
                    super::serialize_display(value, serializer)
                }

                pub fn deserialize<'de, D>(deserializer: D) -> Result<$ty, D::Error>
                where
                    D: serde::Deserializer<'de>,
                {
                    super::deserialize_from_str(deserializer)
                }

                pub mod option {
                    pub fn serialize<S>(
                        value: &Option<$ty>,
                        serializer: S,
                    ) -> Result<S::Ok, S::Error>
                    where
                        S: serde::Serializer,
                    {
                        super::super::serialize_option_display(value, serializer)
                    }

                    pub fn deserialize<'de, D>(deserializer: D) -> Result<Option<$ty>, D::Error>
                    where
                        D: serde::Deserializer<'de>,
                    {
                        super::super::deserialize_option_from_str(deserializer)
                    }
                }
            }
        };
    }

    macro_rules! string_float_module {
        ($module:ident, $ty:ty) => {
            pub mod $module {
                use serde::Deserialize;
                use serde::de::Error as DeError;

                pub fn serialize<S>(value: &$ty, serializer: S) -> Result<S::Ok, S::Error>
                where
                    S: serde::Serializer,
                {
                    super::serialize_display(value, serializer)
                }

                pub fn deserialize<'de, D>(deserializer: D) -> Result<$ty, D::Error>
                where
                    D: serde::Deserializer<'de>,
                {
                    let value = <String as Deserialize>::deserialize(deserializer)?;
                    fast_float2::parse::<$ty, _>(&value).map_err(DeError::custom)
                }

                pub mod option {
                    use serde::Deserialize;
                    use serde::de::Error as DeError;

                    pub fn serialize<S>(
                        value: &Option<$ty>,
                        serializer: S,
                    ) -> Result<S::Ok, S::Error>
                    where
                        S: serde::Serializer,
                    {
                        super::super::serialize_option_display(value, serializer)
                    }

                    pub fn deserialize<'de, D>(deserializer: D) -> Result<Option<$ty>, D::Error>
                    where
                        D: serde::Deserializer<'de>,
                    {
                        let value = <Option<String> as Deserialize>::deserialize(deserializer)?;
                        value
                            .map(|value| {
                                fast_float2::parse::<$ty, _>(&value).map_err(DeError::custom)
                            })
                            .transpose()
                    }
                }
            }
        };
    }

    string_from_str_module!(as_u8, u8);
    string_from_str_module!(as_u16, u16);
    string_from_str_module!(as_u32, u32);
    string_from_str_module!(as_u64, u64);
    string_from_str_module!(as_i8, i8);
    string_from_str_module!(as_i16, i16);
    string_from_str_module!(as_i32, i32);
    string_from_str_module!(as_i64, i64);
    string_float_module!(as_f32, f32);
    string_float_module!(as_f64, f64);

    pub mod as_bool {
        use std::fmt;

        use serde::de::{Error as DeError, Visitor};

        pub fn serialize<S>(value: &bool, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: serde::Serializer,
        {
            serializer.serialize_str(crate::format_bool(value))
        }

        pub fn deserialize<'de, D>(deserializer: D) -> Result<bool, D::Error>
        where
            D: serde::Deserializer<'de>,
        {
            deserializer.deserialize_any(BoolVisitor)
        }

        struct BoolVisitor;

        impl Visitor<'_> for BoolVisitor {
            type Value = bool;

            fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
                formatter.write_str("a boolean string or numeric boolean")
            }

            fn visit_bool<E>(self, value: bool) -> Result<Self::Value, E> {
                Ok(value)
            }

            fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
            where
                E: DeError,
            {
                super::deserialize_bool(value).map_err(DeError::custom)
            }

            fn visit_string<E>(self, value: String) -> Result<Self::Value, E>
            where
                E: DeError,
            {
                self.visit_str(&value)
            }

            fn visit_i64<E>(self, value: i64) -> Result<Self::Value, E>
            where
                E: DeError,
            {
                match value {
                    0 => Ok(false),
                    1 => Ok(true),
                    _ => Err(DeError::custom("invalid boolean number")),
                }
            }

            fn visit_u64<E>(self, value: u64) -> Result<Self::Value, E>
            where
                E: DeError,
            {
                match value {
                    0 => Ok(false),
                    1 => Ok(true),
                    _ => Err(DeError::custom("invalid boolean number")),
                }
            }
        }

        pub mod option {
            use std::fmt;

            use serde::de::Visitor;

            pub fn serialize<S>(value: &Option<bool>, serializer: S) -> Result<S::Ok, S::Error>
            where
                S: serde::Serializer,
            {
                match value {
                    Some(value) => super::serialize(value, serializer),
                    None => serializer.serialize_none(),
                }
            }

            pub fn deserialize<'de, D>(deserializer: D) -> Result<Option<bool>, D::Error>
            where
                D: serde::Deserializer<'de>,
            {
                deserializer.deserialize_option(BoolOptionVisitor)
            }

            struct BoolOptionVisitor;

            impl<'de> Visitor<'de> for BoolOptionVisitor {
                type Value = Option<bool>;

                fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
                    formatter.write_str("an optional boolean string or numeric boolean")
                }

                fn visit_none<E>(self) -> Result<Self::Value, E> {
                    Ok(None)
                }

                fn visit_unit<E>(self) -> Result<Self::Value, E> {
                    Ok(None)
                }

                fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
                where
                    D: serde::Deserializer<'de>,
                {
                    super::deserialize(deserializer).map(Some)
                }
            }
        }
    }

    pub mod as_date {
        use serde::Deserialize;
        use serde::de::Error as DeError;

        use super::*;

        pub fn serialize<S>(value: &Date, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: serde::Serializer,
        {
            serializer.serialize_str(&crate::format_date(value))
        }

        pub fn deserialize<'de, D>(deserializer: D) -> Result<Date, D::Error>
        where
            D: serde::Deserializer<'de>,
        {
            let value = <String as Deserialize>::deserialize(deserializer)?;
            crate::parse_date(&value).map_err(DeError::custom)
        }

        pub mod option {
            use serde::Deserialize;
            use serde::de::Error as DeError;

            use super::*;

            pub fn serialize<S>(value: &Option<Date>, serializer: S) -> Result<S::Ok, S::Error>
            where
                S: serde::Serializer,
            {
                match value {
                    Some(value) => super::serialize(value, serializer),
                    None => serializer.serialize_none(),
                }
            }

            pub fn deserialize<'de, D>(deserializer: D) -> Result<Option<Date>, D::Error>
            where
                D: serde::Deserializer<'de>,
            {
                let value = <Option<String> as Deserialize>::deserialize(deserializer)?;
                value
                    .map(|value| crate::parse_date(&value).map_err(DeError::custom))
                    .transpose()
            }
        }
    }

    pub mod as_naive_datetime {
        use serde::Deserialize;
        use serde::de::Error as DeError;

        use super::*;

        pub fn serialize<S>(value: &PrimitiveDateTime, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: serde::Serializer,
        {
            serializer.serialize_str(&crate::format_naive_datetime(value))
        }

        pub fn deserialize<'de, D>(deserializer: D) -> Result<PrimitiveDateTime, D::Error>
        where
            D: serde::Deserializer<'de>,
        {
            let value = <String as Deserialize>::deserialize(deserializer)?;
            crate::parse_naive_datetime(&value).map_err(DeError::custom)
        }

        pub mod option {
            use serde::Deserialize;
            use serde::de::Error as DeError;

            use super::*;

            pub fn serialize<S>(
                value: &Option<PrimitiveDateTime>,
                serializer: S,
            ) -> Result<S::Ok, S::Error>
            where
                S: serde::Serializer,
            {
                match value {
                    Some(value) => super::serialize(value, serializer),
                    None => serializer.serialize_none(),
                }
            }

            pub fn deserialize<'de, D>(
                deserializer: D,
            ) -> Result<Option<PrimitiveDateTime>, D::Error>
            where
                D: serde::Deserializer<'de>,
            {
                let value = <Option<String> as Deserialize>::deserialize(deserializer)?;
                value
                    .map(|value| crate::parse_naive_datetime(&value).map_err(DeError::custom))
                    .transpose()
            }
        }
    }

    pub mod as_offset_datetime {
        use serde::Deserialize;
        use serde::de::Error as DeError;
        use serde::ser::Error as SerError;

        use super::*;

        pub fn serialize<S>(value: &OffsetDateTime, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: serde::Serializer,
        {
            let value = value.format(&Rfc3339).map_err(SerError::custom)?;
            serializer.serialize_str(&value)
        }

        pub fn deserialize<'de, D>(deserializer: D) -> Result<OffsetDateTime, D::Error>
        where
            D: serde::Deserializer<'de>,
        {
            let value = <String as Deserialize>::deserialize(deserializer)?;
            OffsetDateTime::parse(&value, &Rfc3339).map_err(DeError::custom)
        }

        pub mod option {
            use serde::Deserialize;
            use serde::de::Error as DeError;

            use super::*;

            pub fn serialize<S>(
                value: &Option<OffsetDateTime>,
                serializer: S,
            ) -> Result<S::Ok, S::Error>
            where
                S: serde::Serializer,
            {
                match value {
                    Some(value) => super::serialize(value, serializer),
                    None => serializer.serialize_none(),
                }
            }

            pub fn deserialize<'de, D>(deserializer: D) -> Result<Option<OffsetDateTime>, D::Error>
            where
                D: serde::Deserializer<'de>,
            {
                let value = <Option<String> as Deserialize>::deserialize(deserializer)?;
                value
                    .map(|value| OffsetDateTime::parse(&value, &Rfc3339).map_err(DeError::custom))
                    .transpose()
            }
        }
    }

    pub mod as_time {
        use serde::Deserialize;
        use serde::de::Error as DeError;

        use super::*;

        pub fn serialize<S>(value: &Time, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: serde::Serializer,
        {
            serializer.serialize_str(&crate::format_time(value))
        }

        pub fn deserialize<'de, D>(deserializer: D) -> Result<Time, D::Error>
        where
            D: serde::Deserializer<'de>,
        {
            let value = <String as Deserialize>::deserialize(deserializer)?;
            crate::parse_time(&value).map_err(DeError::custom)
        }

        pub mod option {
            use serde::Deserialize;
            use serde::de::Error as DeError;

            use super::*;

            pub fn serialize<S>(value: &Option<Time>, serializer: S) -> Result<S::Ok, S::Error>
            where
                S: serde::Serializer,
            {
                match value {
                    Some(value) => super::serialize(value, serializer),
                    None => serializer.serialize_none(),
                }
            }

            pub fn deserialize<'de, D>(deserializer: D) -> Result<Option<Time>, D::Error>
            where
                D: serde::Deserializer<'de>,
            {
                let value = <Option<String> as Deserialize>::deserialize(deserializer)?;
                let Some(value) = value else {
                    return Ok(None);
                };
                let value = value.trim();
                if value.is_empty() {
                    return Ok(None);
                }
                crate::parse_time(value).map(Some).map_err(DeError::custom)
            }
        }
    }

    fn serialize_display<T, S>(value: &T, serializer: S) -> Result<S::Ok, S::Error>
    where
        T: fmt::Display,
        S: serde::Serializer,
    {
        serializer.serialize_str(&value.to_string())
    }

    fn serialize_option_display<T, S>(value: &Option<T>, serializer: S) -> Result<S::Ok, S::Error>
    where
        T: fmt::Display,
        S: serde::Serializer,
    {
        match value {
            Some(value) => serialize_display(value, serializer),
            None => serializer.serialize_none(),
        }
    }

    fn deserialize_from_str<'de, T, D>(deserializer: D) -> Result<T, D::Error>
    where
        T: FromStr,
        T::Err: fmt::Display,
        D: serde::Deserializer<'de>,
    {
        let value = String::deserialize(deserializer)?;
        value.parse::<T>().map_err(DeError::custom)
    }

    fn deserialize_option_from_str<'de, T, D>(deserializer: D) -> Result<Option<T>, D::Error>
    where
        T: FromStr,
        T::Err: fmt::Display,
        D: serde::Deserializer<'de>,
    {
        let value = Option::<String>::deserialize(deserializer)?;
        value
            .map(|value| value.parse::<T>().map_err(DeError::custom))
            .transpose()
    }

    fn deserialize_bool(value: &str) -> Result<bool, &'static str> {
        match value {
            "1" => Ok(true),
            "0" => Ok(false),
            value if value.eq_ignore_ascii_case("true") => Ok(true),
            value if value.eq_ignore_ascii_case("false") => Ok(false),
            _ => Err("invalid boolean string"),
        }
    }
}

#[cfg(feature = "serde")]
pub mod serde_integer {
    pub mod as_bool {
        use crate::serde_string::as_bool as string_bool;

        pub fn serialize<S>(value: &bool, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: serde::Serializer,
        {
            serializer.serialize_u8(u8::from(*value))
        }

        pub fn deserialize<'de, D>(deserializer: D) -> Result<bool, D::Error>
        where
            D: serde::Deserializer<'de>,
        {
            string_bool::deserialize(deserializer)
        }

        pub mod option {
            use crate::serde_string::as_bool::option as string_bool_option;

            pub fn serialize<S>(value: &Option<bool>, serializer: S) -> Result<S::Ok, S::Error>
            where
                S: serde::Serializer,
            {
                match value {
                    Some(value) => super::serialize(value, serializer),
                    None => serializer.serialize_none(),
                }
            }

            pub fn deserialize<'de, D>(deserializer: D) -> Result<Option<bool>, D::Error>
            where
                D: serde::Deserializer<'de>,
            {
                string_bool_option::deserialize(deserializer)
            }
        }
    }
}

#[cfg(feature = "json")]
pub mod treat_error_as_none {
    use serde::de::DeserializeOwned;
    use serde::{Deserialize, Deserializer, Serialize, Serializer};

    pub fn serialize<S, T>(value: &Option<T>, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
        T: Serialize,
    {
        match value {
            Some(inner) => inner.serialize(serializer),
            None => serializer.serialize_none(),
        }
    }

    pub fn deserialize<'de, D, T>(deserializer: D) -> Result<Option<T>, D::Error>
    where
        D: Deserializer<'de>,
        T: DeserializeOwned,
    {
        let value = serde_json::Value::deserialize(deserializer)?;
        match T::deserialize(value) {
            Ok(parsed) => Ok(Some(parsed)),
            Err(_) => Ok(None),
        }
    }
}

pub fn insert_header(
    headers: &mut http::HeaderMap,
    name: &'static str,
    value: &str,
) -> Result<(), Error> {
    headers.insert(
        HeaderName::from_bytes(name.as_bytes())?,
        HeaderValue::from_str(value)?,
    );
    Ok(())
}

pub fn has_json_content_type(headers: &http::HeaderMap) -> bool {
    headers
        .get(CONTENT_TYPE)
        .and_then(|value| value.to_str().ok())
        .is_some_and(is_json_media_type)
}

fn is_json_media_type(value: &str) -> bool {
    let media_type = value.split(';').next().unwrap_or(value).trim();
    if media_type.eq_ignore_ascii_case("application/json") {
        return true;
    }

    let Some((_, subtype)) = media_type.rsplit_once('/') else {
        return false;
    };
    ends_with_ignore_ascii_case(subtype, "+json")
}

fn ends_with_ignore_ascii_case(value: &str, suffix: &str) -> bool {
    let value = value.as_bytes();
    let suffix = suffix.as_bytes();
    value.len() >= suffix.len() && value[value.len() - suffix.len()..].eq_ignore_ascii_case(suffix)
}

fn append_percent_encoded(out: &mut String, bytes: &[u8]) {
    const HEX: &[u8; 16] = b"0123456789ABCDEF";

    for &byte in bytes {
        if is_unreserved(byte) {
            out.push(byte as char);
        } else {
            out.push('%');
            out.push(HEX[(byte >> 4) as usize] as char);
            out.push(HEX[(byte & 0x0f) as usize] as char);
        }
    }
}

const fn is_unreserved(byte: u8) -> bool {
    matches!(
        byte,
        b'A'..=b'Z' | b'a'..=b'z' | b'0'..=b'9' | b'-' | b'.' | b'_' | b'~'
    )
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn encodes_path_segments() {
        let mut out = String::new();
        append_path_segment(&mut out, "a/b c");
        assert_eq!(out, "a%2Fb%20c");
    }

    #[test]
    fn appends_query_pairs() {
        let mut out = String::from("/pets");
        let mut first = true;
        append_query_pair(&mut out, &mut first, "tag name", "small/dog");
        append_query_pair(&mut out, &mut first, "limit", "10");
        assert_eq!(out, "/pets?tag%20name=small%2Fdog&limit=10");
    }

    #[test]
    fn parses_range_strings() {
        assert_eq!(parse_range::<u8>("14-17").unwrap(), (Some(14), Some(17)));
        assert_eq!(parse_range::<u8>("14-").unwrap(), (Some(14), None));
        assert_eq!(parse_range::<u8>("-17").unwrap(), (None, Some(17)));
        assert_eq!(parse_range::<u8>("").unwrap(), (None, None));
        assert!(matches!(
            parse_range::<u8>("14-17-20"),
            Err(ParseRangeError::TooManySeparators)
        ));
    }

    #[test]
    fn formats_range_strings() {
        assert_eq!(format_range(&Some(14), &Some(17)), "14-17");
        assert_eq!(format_range(&Some(14), &None::<u8>), "14-");
        assert_eq!(format_range(&None::<u8>, &Some(17)), "-17");
        assert_eq!(format_range(&None::<u8>, &None::<u8>), "");
    }

    #[test]
    fn parses_and_formats_time_strings() {
        let time = parse_time("0620").unwrap();
        assert_eq!(time.hour(), 6);
        assert_eq!(time.minute(), 20);
        assert_eq!(format_time(&time), "0620");
        assert_eq!(parse_time("6:20"), Err(ParseTimeError::InvalidFormat));
        assert_eq!(parse_time("2400"), Err(ParseTimeError::ComponentRange));
    }

    #[test]
    fn parses_and_formats_date_strings() {
        let date = parse_date("2024-07-16").unwrap();
        assert_eq!(
            date,
            Date::from_calendar_date(2024, Month::July, 16).unwrap()
        );
        assert_eq!(format_date(&date), "2024-07-16");
        assert_eq!(parse_date("2024-7-16"), Err(ParseDateError::InvalidFormat));
        assert_eq!(parse_date("not-a-date"), Err(ParseDateError::InvalidFormat));
    }

    #[test]
    fn parses_and_formats_naive_datetime_strings() {
        let datetime = parse_naive_datetime("2024-07-16T23:59:00").unwrap();
        assert_eq!(datetime.hour(), 23);
        assert_eq!(datetime.minute(), 59);
        assert_eq!(datetime.second(), 0);
        assert_eq!(format_naive_datetime(&datetime), "2024-07-16T23:59:00");
        assert_eq!(
            parse_naive_datetime("2024-07-16T23:59"),
            Err(ParseNaiveDateTimeError::InvalidFormat)
        );
        assert_eq!(
            parse_naive_datetime("2024-07-16 23:59:00"),
            Err(ParseNaiveDateTimeError::InvalidFormat)
        );
    }

    #[cfg(all(feature = "serde", feature = "json"))]
    #[test]
    fn serde_string_naive_datetime_round_trips() {
        #[derive(serde::Deserialize, serde::Serialize)]
        struct Value {
            #[serde(with = "crate::serde_string::as_naive_datetime")]
            at: PrimitiveDateTime,
        }

        let at = parse_naive_datetime("2024-07-16T23:59:00").unwrap();
        let encoded = serde_json::to_value(Value { at }).unwrap();
        assert_eq!(encoded, serde_json::json!({ "at": "2024-07-16T23:59:00" }));

        let decoded = serde_json::from_value::<Value>(encoded).unwrap();
        assert_eq!(decoded.at, at);
    }

    #[cfg(all(feature = "serde", feature = "json"))]
    #[test]
    fn serde_string_date_round_trips() {
        #[derive(serde::Deserialize, serde::Serialize)]
        struct Value {
            #[serde(with = "crate::serde_string::as_date")]
            day: Date,
        }

        let date = Date::from_calendar_date(2024, Month::July, 16).unwrap();
        let encoded = serde_json::to_value(Value { day: date }).unwrap();
        assert_eq!(encoded, serde_json::json!({ "day": "2024-07-16" }));

        let decoded = serde_json::from_value::<Value>(encoded).unwrap();
        assert_eq!(decoded.day, date);
    }

    #[test]
    fn recognizes_json_content_types() {
        let mut headers = http::HeaderMap::new();
        headers.insert(
            CONTENT_TYPE,
            http::HeaderValue::from_static("application/problem+json; charset=utf-8"),
        );
        assert!(has_json_content_type(&headers));
    }

    #[test]
    fn response_parts_holds_status_headers_body() {
        let mut headers = http::HeaderMap::new();
        headers.insert(
            CONTENT_TYPE,
            http::HeaderValue::from_static("application/json"),
        );
        let body = br#"{"ok":true}"#.to_vec();
        let parts = ResponseParts {
            status: http::StatusCode::OK,
            headers,
            body,
        };
        assert_eq!(parts.status, http::StatusCode::OK);
        assert_eq!(parts.headers.get(CONTENT_TYPE).unwrap(), "application/json");
        assert_eq!(parts.body, br#"{"ok":true}"#);
    }

    #[cfg(all(feature = "serde", feature = "json"))]
    #[test]
    fn serde_string_bool_accepts_string_and_numeric_values() {
        #[derive(serde::Deserialize, serde::Serialize)]
        struct Value {
            #[serde(with = "crate::serde_string::as_bool")]
            monitored: bool,
        }

        let numeric = serde_json::from_str::<Value>(r#"{"monitored":0}"#).unwrap();
        assert!(!numeric.monitored);

        let string = serde_json::from_str::<Value>(r#"{"monitored":"1"}"#).unwrap();
        assert!(string.monitored);

        let encoded = serde_json::to_value(Value { monitored: false }).unwrap();
        assert_eq!(encoded, serde_json::json!({ "monitored": "0" }));
    }

    #[cfg(all(feature = "serde", feature = "json"))]
    #[test]
    fn serde_integer_bool_accepts_numeric_values() {
        #[derive(serde::Deserialize, serde::Serialize)]
        struct Value {
            #[serde(with = "crate::serde_integer::as_bool")]
            monitored: bool,
        }

        let numeric = serde_json::from_str::<Value>(r#"{"monitored":0}"#).unwrap();
        assert!(!numeric.monitored);

        let encoded = serde_json::to_value(Value { monitored: true }).unwrap();
        assert_eq!(encoded, serde_json::json!({ "monitored": 1 }));
    }
}