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use std::error;
use std::fmt;
use std::result;
use std::time::Duration;

use async_trait::async_trait;
use nebula_fbthrift_graph::{
    errors::graph_service::ExecuteError,
    types::{ErrorCode, ExecutionResponse},
};

use serde::de::DeserializeOwned;
use serde_nebula_fbthrift_graph::de::{data::DataDeserializeError, deserialize_execution_response};

#[async_trait]
pub trait GraphQuery {
    async fn query_as<D: DeserializeOwned>(
        &mut self,
        stmt: &str,
    ) -> result::Result<GraphQueryOutput<D>, GraphQueryError>;

    async fn query(&mut self, stmt: &str) -> result::Result<GraphQueryOutput<()>, GraphQueryError> {
        self.query_as(stmt).await
    }

    async fn show_hosts(&mut self) -> result::Result<GraphQueryOutput<Host>, GraphQueryError> {
        self.query_as(STMT_SHOW_HOSTS).await
    }
    async fn show_spaces(&mut self) -> result::Result<GraphQueryOutput<Space>, GraphQueryError> {
        self.query_as(STMT_SHOW_SPACES).await
    }
}

#[derive(Debug)]
pub struct GraphQueryOutput<D>
where
    D: DeserializeOwned,
{
    pub latency: Duration,
    pub space_name: Option<String>,
    pub data_set: Vec<D>,
}

impl<D> GraphQueryOutput<D>
where
    D: DeserializeOwned,
{
    pub fn new(res: ExecutionResponse) -> result::Result<Self, GraphQueryError> {
        let latency = Duration::from_micros(res.latency_in_us as u64);
        let space_name = res.space_name.clone();
        let data_set = deserialize_execution_response::<D>(&res)
            .map_err(GraphQueryError::DataDeserializeError)?;

        Ok(Self {
            latency,
            space_name,
            data_set,
        })
    }
}

//
//
//
#[derive(Debug)]
pub enum GraphQueryError {
    ExecuteError(ExecuteError),
    ResponseError(ErrorCode, Option<String>),
    DataDeserializeError(DataDeserializeError),
}

impl fmt::Display for GraphQueryError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            Self::ExecuteError(err) => write!(f, "ExecuteError {}", err),
            Self::ResponseError(err_code, err_msg) => write!(
                f,
                "ResponseError err_code:{} err_msg:{:?}",
                err_code, err_msg
            ),
            Self::DataDeserializeError(err) => write!(f, "DataDeserializeError {}", err),
        }
    }
}

impl error::Error for GraphQueryError {
    fn description(&self) -> &str {
        match self {
            Self::ExecuteError(_) => "ExecuteError",
            Self::ResponseError(_, _) => "ResponseError",
            Self::DataDeserializeError(_) => "DataDeserializeError",
        }
    }
}

//
//
//
use serde::Deserialize;

const STMT_SHOW_HOSTS: &str = "SHOW HOSTS;";
#[derive(Deserialize, Debug)]
pub struct Host {
    #[serde(rename(deserialize = "Ip"))]
    pub ip: String,
    #[serde(rename(deserialize = "Port"))]
    pub port: String,
    #[serde(rename(deserialize = "Status"))]
    pub status: String,
    #[serde(rename(deserialize = "Leader count"))]
    pub leader_count: u64,
    #[serde(rename(deserialize = "Leader distribution"))]
    pub leader_distribution: String,
    #[serde(rename(deserialize = "Partition distribution"))]
    pub partition_distribution: String,
}

const STMT_SHOW_SPACES: &str = "SHOW SPACES;";
#[derive(Deserialize, Debug)]
pub struct Space {
    #[serde(rename(deserialize = "Name"))]
    pub name: String,
}

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

    use std::io;

    #[test]
    fn impl_std_fmt_display() {
        let err = GraphQueryError::ResponseError(ErrorCode::E_DISCONNECTED, None);
        println!("{}", err.to_string());
    }

    #[test]
    fn impl_std_error_error() {
        let err = io::Error::new(
            io::ErrorKind::Other,
            GraphQueryError::ResponseError(ErrorCode::E_DISCONNECTED, None),
        );
        println!("{}", err.to_string());
    }
}