use super::{QianwenClient, Client, ExtraConfig, PromptType, SendData, Model};

use crate::{
    config::GlobalConfig,
    render::ReplyHandler,
    utils::PromptKind,
};

use anyhow::{anyhow, bail, Result};
use async_trait::async_trait;
use futures_util::StreamExt;
use reqwest::{Client as ReqwestClient, RequestBuilder};
use reqwest_eventsource::{Error as EventSourceError, Event, RequestBuilderExt};
use serde::Deserialize;
use serde_json::{json, Value};

const API_URL: &str =
    "https://dashscope.aliyuncs.com/api/v1/services/aigc/text-generation/generation";

const MODELS: [(&str, usize); 2] = [("qwen-turbo", 6144), ("qwen-plus", 6144)];

#[derive(Debug, Clone, Deserialize, Default)]
pub struct QianwenConfig {
    pub name: Option<String>,
    pub api_key: Option<String>,
    pub extra: Option<ExtraConfig>,
}

#[async_trait]
impl Client for QianwenClient {
    fn config(&self) -> (&GlobalConfig, &Option<ExtraConfig>) {
        (&self.global_config, &self.config.extra)
    }

    async fn send_message_inner(&self, client: &ReqwestClient, data: SendData) -> Result<String> {
        let builder = self.request_builder(client, data)?;
        send_message(builder).await
    }

    async fn send_message_streaming_inner(
        &self,
        client: &ReqwestClient,
        handler: &mut ReplyHandler,
        data: SendData,
    ) -> Result<()> {
        let builder = self.request_builder(client, data)?;
        send_message_streaming(builder, handler).await
    }
}

impl QianwenClient {
    config_get_fn!(api_key, get_api_key);

    pub const PROMPTS: [PromptType<'static>; 1] =
        [("api_key", "API Key:", true, PromptKind::String)];

    pub fn list_models(local_config: &QianwenConfig) -> Vec<Model> {
        let client_name = Self::name(local_config);
        MODELS
            .into_iter()
            .map(|(name, max_tokens)| Model::new(client_name, name).set_max_tokens(Some(max_tokens)))
            .collect()
    }

    fn request_builder(&self, client: &ReqwestClient, data: SendData) -> Result<RequestBuilder> {
        let api_key = self.get_api_key()?;

        let stream = data.stream;
        let body = build_body(data, self.model.name.clone());

        debug!("Qianwen Request: {API_URL} {body}");

        let mut builder = client.post(API_URL).bearer_auth(api_key).json(&body);
        if stream {
            builder = builder.header("X-DashScope-SSE", "enable");
        }

        Ok(builder)
    }
}

async fn send_message(builder: RequestBuilder) -> Result<String> {
    let data: Value = builder.send().await?.json().await?;
    check_error(&data)?;

    let output = data["output"]["text"].as_str()
        .ok_or_else(|| anyhow!("Unexpected response {data}"))?;

    Ok(output.to_string())
}

async fn send_message_streaming(
    builder: RequestBuilder,
    handler: &mut ReplyHandler,
) -> Result<()> {
    let mut es = builder.eventsource()?;
    let mut offset = 0;

    while let Some(event) = es.next().await {
        match event {
            Ok(Event::Open) => {}
            Ok(Event::Message(message)) => {
                let data: Value = serde_json::from_str(&message.data)?;
                if let Some(text) = data["output"]["text"].as_str() {

                    let text = &text[offset..];
                    handler.text(text)?;
                    offset += text.len();
                }
            }
            Err(err) => {
                match err {
                    EventSourceError::InvalidStatusCode(_, res) => {
                        let data: Value = res.json().await?;
                        check_error(&data)?;
                        bail!("Request failed");
                    }
                    EventSourceError::StreamEnded => {}
                    _ => {
                        bail!("{}", err);
                    }
                }
                es.close();
            }
        }
    }

    Ok(())
}

fn check_error(data: &Value) -> Result<()> {
    if let Some(code) = data["code"].as_str() {
        if let Some(message) = data["message"].as_str() {
            bail!("{message}");
        } else {
            bail!("{code}");
        }
    }
    Ok(())
}

fn build_body(data: SendData, model: String) -> Value {
    let SendData {
        messages,
        temperature,
        stream: _,
    } = data;

    let mut parameters = json!({});

    if let Some(v) = temperature {
        parameters["temperature"] = v.into();
    }

    json!({
        "model": model,
        "input": json!({
            "messages": messages,
        }),
        "parameters": parameters
    })
}