use crate::{
    http::Body,
    rpc::{typed_data::Data, TypedData},
    FromVec,
};
use serde::de::Error;
use serde::Deserialize;
use serde_json::{from_str, Result, Value};
use std::borrow::Cow;
use std::fmt;
use std::str::from_utf8;

/// Represents a Service Bus message output binding.
///
/// The following binding attributes are supported:
///
/// | Name                | Description                                                                                                                               |
/// |---------------------|-------------------------------------------------------------------------------------------------------------------------------------------|
/// | `name`              | The name of the parameter being bound.                                                                                                    |
/// | `queue_name`        | The name of the queue. Use only if sending queue messages, not for a topic.                                                               |
/// | `topic_name`        | The name of the topic. Use only if sending topic messages, not for a queue.                                                               |
/// | `subscription_name` | The name of the subscription. Use only if sending topic messages, not for a queue.                                                        |
/// | `connection`        | The name of an app setting that contains the Service Bus connection string to use for this binding. Defaults to `AzureWebJobsServiceBus`. |
///
/// # Examples
///
/// An example that creates a Service Bus queue message based on a HTTP trigger:
///
/// ```rust
/// use azure_functions::{
///     bindings::{HttpRequest, ServiceBusMessage},
///     func,
/// };
///
/// #[func]
/// #[binding(name = "$return", queue_name = "example", connection = "connection")]
/// pub fn create_queue_message(req: HttpRequest) -> ServiceBusMessage {
///     format!(
///         "Hello from Rust, {}!\n",
///         req.query_params().get("name").map_or("stranger", |x| x)
///     )
///     .into()
/// }
/// ```
///
/// An example that creates a Service Bus topic message based on a HTTP trigger:
///
/// ```rust
/// use azure_functions::{
///     bindings::{HttpRequest, ServiceBusMessage},
///     func,
/// };
///
/// #[func]
/// #[binding(
///     name = "$return",
///     topic_name = "mytopic",
///     subscription_name = "mysubscription",
///     connection = "connection"
/// )]
/// pub fn create_topic_message(req: HttpRequest) -> ServiceBusMessage {
///     format!(
///         "Hello from Rust, {}!\n",
///         req.query_params().get("name").map_or("stranger", |x| x)
///     )
///     .into()
/// }
/// ```
#[derive(Debug, Clone)]
pub struct ServiceBusMessage(TypedData);

impl ServiceBusMessage {
    /// Gets the content of the message as a string.
    ///
    /// Returns None if there is no valid string representation of the message.
    pub fn as_str(&self) -> Option<&str> {
        match &self.0.data {
            Some(Data::String(s)) => Some(s),
            Some(Data::Json(s)) => Some(s),
            Some(Data::Bytes(b)) => from_utf8(b).ok(),
            Some(Data::Stream(s)) => from_utf8(s).ok(),
            _ => None,
        }
    }

    /// Gets the content of the message as a slice of bytes.
    pub fn as_bytes(&self) -> &[u8] {
        match &self.0.data {
            Some(Data::String(s)) => s.as_bytes(),
            Some(Data::Json(s)) => s.as_bytes(),
            Some(Data::Bytes(b)) => b,
            Some(Data::Stream(s)) => s,
            _ => panic!("unexpected data for service bus message content"),
        }
    }

    /// Deserializes the message as JSON to the requested type.
    pub fn as_json<'b, T>(&'b self) -> Result<T>
    where
        T: Deserialize<'b>,
    {
        from_str(
            self.as_str().ok_or_else(|| {
                ::serde_json::Error::custom("service bus message is not valid UTF-8")
            })?,
        )
    }
}

impl fmt::Display for ServiceBusMessage {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self.as_str().unwrap_or(""))
    }
}

impl<'a> From<&'a str> for ServiceBusMessage {
    fn from(content: &'a str) -> Self {
        ServiceBusMessage(TypedData {
            data: Some(Data::String(content.to_owned())),
        })
    }
}

impl From<String> for ServiceBusMessage {
    fn from(content: String) -> Self {
        ServiceBusMessage(TypedData {
            data: Some(Data::String(content)),
        })
    }
}

impl From<&Value> for ServiceBusMessage {
    fn from(content: &Value) -> Self {
        ServiceBusMessage(TypedData {
            data: Some(Data::Json(content.to_string())),
        })
    }
}

impl From<Value> for ServiceBusMessage {
    fn from(content: Value) -> Self {
        ServiceBusMessage(TypedData {
            data: Some(Data::Json(content.to_string())),
        })
    }
}

impl<'a> From<&'a [u8]> for ServiceBusMessage {
    fn from(content: &'a [u8]) -> Self {
        ServiceBusMessage(TypedData {
            data: Some(Data::Bytes(content.to_owned())),
        })
    }
}

impl From<Vec<u8>> for ServiceBusMessage {
    fn from(content: Vec<u8>) -> Self {
        ServiceBusMessage(TypedData {
            data: Some(Data::Bytes(content)),
        })
    }
}

#[doc(hidden)]
impl From<TypedData> for ServiceBusMessage {
    fn from(data: TypedData) -> Self {
        ServiceBusMessage(data)
    }
}

#[doc(hidden)]
impl FromVec<ServiceBusMessage> for TypedData {
    fn from_vec(vec: Vec<ServiceBusMessage>) -> Self {
        TypedData {
            data: Some(Data::Json(
                Value::Array(vec.into_iter().map(Into::into).collect()).to_string(),
            )),
        }
    }
}

impl Into<String> for ServiceBusMessage {
    fn into(self) -> String {
        match self.0.data {
            Some(Data::String(s)) => s,
            Some(Data::Json(s)) => s,
            Some(Data::Bytes(b)) => String::from_utf8(b)
                .expect("service bus message does not contain valid UTF-8 bytes"),
            Some(Data::Stream(s)) => String::from_utf8(s)
                .expect("service bus message does not contain valid UTF-8 bytes"),
            _ => panic!("unexpected data for service bus message content"),
        }
    }
}

impl Into<Value> for ServiceBusMessage {
    fn into(self) -> Value {
        // TODO: this is not an efficient encoding for bytes/stream
        match self.0.data {
            Some(Data::String(s)) => Value::String(s),
            Some(Data::Json(s)) => {
                from_str(&s).expect("service bus message does not contain valid JSON data")
            }
            Some(Data::Bytes(b)) => Value::Array(
                b.iter()
                    .map(|n| Value::Number(u64::from(*n).into()))
                    .collect(),
            ),
            Some(Data::Stream(s)) => Value::Array(
                s.iter()
                    .map(|n| Value::Number(u64::from(*n).into()))
                    .collect(),
            ),
            _ => panic!("unexpected data for service bus message content"),
        }
    }
}

impl Into<Vec<u8>> for ServiceBusMessage {
    fn into(self) -> Vec<u8> {
        match self.0.data {
            Some(Data::String(s)) => s.into_bytes(),
            Some(Data::Json(s)) => s.into_bytes(),
            Some(Data::Bytes(b)) => b,
            Some(Data::Stream(s)) => s,
            _ => panic!("unexpected data for service bus message content"),
        }
    }
}

impl<'a> Into<Body<'a>> for ServiceBusMessage {
    fn into(self) -> Body<'a> {
        match self.0.data {
            Some(Data::String(s)) => s.into(),
            Some(Data::Json(s)) => Body::Json(Cow::from(s)),
            Some(Data::Bytes(b)) => b.into(),
            Some(Data::Stream(s)) => s.into(),
            _ => panic!("unexpected data for service bus message content"),
        }
    }
}

#[doc(hidden)]
impl Into<TypedData> for ServiceBusMessage {
    fn into(self) -> TypedData {
        self.0
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde::{Deserialize, Serialize};
    use serde_json::{json, to_value};
    use std::fmt::Write;

    #[test]
    fn it_has_string_content() {
        const MESSAGE: &'static str = "test message";

        let message: ServiceBusMessage = MESSAGE.into();
        assert_eq!(message.as_str().unwrap(), MESSAGE);

        let data: TypedData = message.into();
        assert_eq!(data.data, Some(Data::String(MESSAGE.to_string())));
    }

    #[test]
    fn it_has_json_content() {
        #[derive(Serialize, Deserialize)]
        struct SerializedData {
            message: String,
        };

        const MESSAGE: &'static str = "test";

        let data = SerializedData {
            message: MESSAGE.to_string(),
        };

        let message: ServiceBusMessage = ::serde_json::to_value(data).unwrap().into();
        assert_eq!(
            message.as_json::<SerializedData>().unwrap().message,
            MESSAGE
        );

        let data: TypedData = message.into();
        assert_eq!(
            data.data,
            Some(Data::Json(r#"{"message":"test"}"#.to_string()))
        );
    }

    #[test]
    fn it_has_bytes_content() {
        const MESSAGE: &'static [u8] = &[1, 2, 3];

        let message: ServiceBusMessage = MESSAGE.into();
        assert_eq!(message.as_bytes(), MESSAGE);

        let data: TypedData = message.into();
        assert_eq!(data.data, Some(Data::Bytes(MESSAGE.to_vec())));
    }

    #[test]
    fn it_displays_as_a_string() {
        const MESSAGE: &'static str = "test";

        let message: ServiceBusMessage = MESSAGE.into();

        let mut s = String::new();
        write!(s, "{}", message).unwrap();

        assert_eq!(s, MESSAGE);
    }

    #[test]
    fn it_converts_from_str() {
        let message: ServiceBusMessage = "test".into();
        assert_eq!(message.as_str().unwrap(), "test");
    }

    #[test]
    fn it_converts_from_string() {
        let message: ServiceBusMessage = "test".to_string().into();
        assert_eq!(message.as_str().unwrap(), "test");
    }

    #[test]
    fn it_converts_from_json() {
        let message: ServiceBusMessage = to_value("hello world").unwrap().into();
        assert_eq!(message.as_str().unwrap(), r#""hello world""#);
    }

    #[test]
    fn it_converts_from_u8_slice() {
        let message: ServiceBusMessage = [0, 1, 2][..].into();
        assert_eq!(message.as_bytes(), [0, 1, 2]);
    }

    #[test]
    fn it_converts_from_u8_vec() {
        let message: ServiceBusMessage = vec![0, 1, 2].into();
        assert_eq!(message.as_bytes(), [0, 1, 2]);
    }

    #[test]
    fn it_converts_to_string() {
        let message: ServiceBusMessage = "hello world!".into();
        let s: String = message.into();
        assert_eq!(s, "hello world!");
    }

    #[test]
    fn it_converts_to_json() {
        let message: ServiceBusMessage = json!({"hello": "world"}).into();
        let value: Value = message.into();
        assert_eq!(value.to_string(), r#"{"hello":"world"}"#);
    }

    #[test]
    fn it_converts_to_bytes() {
        let message: ServiceBusMessage = vec![1, 2, 3].into();
        let bytes: Vec<u8> = message.into();
        assert_eq!(bytes, [1, 2, 3]);
    }

    #[test]
    fn it_converts_to_body() {
        let message: ServiceBusMessage = "hello world!".into();
        let body: Body = message.into();
        assert_eq!(body.as_str().unwrap(), "hello world!");

        let message: ServiceBusMessage = json!({"hello": "world"}).into();
        let body: Body = message.into();
        assert_eq!(body.as_str().unwrap(), r#"{"hello":"world"}"#);

        let message: ServiceBusMessage = vec![1, 2, 3].into();
        let body: Body = message.into();
        assert_eq!(body.as_bytes(), [1, 2, 3]);
    }

    #[test]
    fn it_converts_to_typed_data() {
        let message: ServiceBusMessage = "test".into();
        let data: TypedData = message.into();
        assert_eq!(data.data, Some(Data::String("test".to_string())));

        let message: ServiceBusMessage = to_value("test").unwrap().into();
        let data: TypedData = message.into();
        assert_eq!(data.data, Some(Data::Json(r#""test""#.to_string())));

        let message: ServiceBusMessage = vec![1, 2, 3].into();
        let data: TypedData = message.into();
        assert_eq!(data.data, Some(Data::Bytes([1, 2, 3].to_vec())));
    }
}