use super::{openai::OpenAIConfig, ClientConfig, Message, Model, ReplyHandler};

use crate::{
    config::{GlobalConfig, Input},
    render::{render_error, render_stream},
    utils::{prompt_input_integer, prompt_input_string, tokenize, AbortSignal, PromptKind},
};

use anyhow::{bail, Context, Result};
use async_trait::async_trait;
use futures_util::{Stream, StreamExt};
use reqwest::{Client as ReqwestClient, ClientBuilder, Proxy, RequestBuilder};
use serde::Deserialize;
use serde_json::{json, Value};
use std::{env, future::Future, time::Duration};
use tokio::{sync::mpsc::unbounded_channel, time::sleep};

#[macro_export]
macro_rules! register_client {
    (
        $(($module:ident, $name:literal, $config:ident, $client:ident),)+
    ) => {
        $(
            mod $module;
        )+
        $(
            use self::$module::$config;
        )+

        #[derive(Debug, Clone, serde::Deserialize)]
        #[serde(tag = "type")]
        pub enum ClientConfig {
            $(
                #[serde(rename = $name)]
                $config($config),
            )+
            #[serde(other)]
            Unknown,
        }


        $(
            #[derive(Debug)]
            pub struct $client {
                global_config: $crate::config::GlobalConfig,
                config: $config,
                model: $crate::client::Model,
            }

            impl $client {
                pub const NAME: &'static str = $name;

                pub fn init(global_config: &$crate::config::GlobalConfig) -> Option<Box<dyn Client>> {
                    let model = global_config.read().model.clone();
                    let config = global_config.read().clients.iter().find_map(|client_config| {
                        if let ClientConfig::$config(c) = client_config {
                            if Self::name(c) == &model.client_name {
                                return Some(c.clone())
                            }
                        }
                        None
                    })?;

                    Some(Box::new(Self {
                        global_config: global_config.clone(),
                        config,
                        model,
                    }))
                }

                pub fn name(config: &$config) -> &str {
                    config.name.as_deref().unwrap_or(Self::NAME)
                }
            }

        )+

        pub fn init_client(config: &$crate::config::GlobalConfig) -> anyhow::Result<Box<dyn Client>> {
            None
            $(.or_else(|| $client::init(config)))+
            .ok_or_else(|| {
                let model = config.read().model.clone();
                anyhow::anyhow!("Unknown client '{}'", &model.client_name)
            })
        }

        pub fn ensure_model_capabilities(client: &mut dyn Client, capabilities: $crate::client::ModelCapabilities) -> anyhow::Result<()> {
            if !client.model().capabilities.contains(capabilities) {
                let models = client.list_models();
                if let Some(model) = models.into_iter().find(|v| v.capabilities.contains(capabilities)) {
                    client.set_model(model);
                } else {
                    anyhow::bail!(
                        "The current model lacks the corresponding capability."
                    );
                }
            }
            Ok(())
        }

        pub fn list_client_types() -> Vec<&'static str> {
            vec![$($client::NAME,)+]
        }

        pub fn create_client_config(client: &str) -> anyhow::Result<(String, serde_json::Value)> {
            $(
                if client == $client::NAME {
                    return create_config(&$client::PROMPTS, $client::NAME)
                }
            )+
            anyhow::bail!("Unknown client '{}'", client)
        }

        pub fn list_models(config: &$crate::config::Config) -> Vec<$crate::client::Model> {
            config
                .clients
                .iter()
                .flat_map(|v| match v {
                    $(ClientConfig::$config(c) => $client::list_models(c),)+
                    ClientConfig::Unknown => vec![],
                })
                .collect()
        }

    };
}

#[macro_export]
macro_rules! openai_compatible_client {
    (
        $config:ident,
        $client:ident,
        $api_base:literal,
        [$(($name:literal, $capabilities:literal, $max_input_tokens:literal $(, $max_output_tokens:literal)? )),+$(,)?]
    ) => {
        use $crate::client::openai::openai_build_body;
        use $crate::client::{ExtraConfig, $client, Model, ModelConfig, PromptType, SendData};

        use $crate::utils::PromptKind;

        use anyhow::Result;
        use reqwest::{Client as ReqwestClient, RequestBuilder};
        use serde::Deserialize;

        const API_BASE: &str = $api_base;

        #[derive(Debug, Clone, Deserialize)]
        pub struct $config {
            pub name: Option<String>,
            pub api_key: Option<String>,
            #[serde(default)]
            pub models: Vec<ModelConfig>,
            pub extra: Option<ExtraConfig>,
        }

        impl_client_trait!(
            $client,
            $crate::client::openai::openai_send_message,
            $crate::client::openai::openai_send_message_streaming
        );


        impl $client {
            list_models_fn!(
                $config,
                [
                    $(
                        ($name, $capabilities, $max_input_tokens $(, $max_output_tokens)?),
                    )+
                ]
            );
            config_get_fn!(api_key, get_api_key);

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

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

                let body = openai_build_body(data, &self.model);

                let url = format!("{API_BASE}/chat/completions");

                debug!("Request: {url} {body}");

                let mut builder = client.post(url).json(&body);
                if let Some(api_key) = api_key {
                    builder = builder.bearer_auth(api_key);
                }

                Ok(builder)
            }
        }

    }
}

#[macro_export]
macro_rules! client_common_fns {
    () => {
        fn config(
            &self,
        ) -> (
            &$crate::config::GlobalConfig,
            &Option<$crate::client::ExtraConfig>,
        ) {
            (&self.global_config, &self.config.extra)
        }

        fn list_models(&self) -> Vec<Model> {
            Self::list_models(&self.config)
        }

        fn model(&self) -> &Model {
            &self.model
        }

        fn set_model(&mut self, model: Model) {
            self.model = model;
        }
    };
}

#[macro_export]
macro_rules! impl_client_trait {
    ($client:ident, $send_message:path, $send_message_streaming:path) => {
        #[async_trait::async_trait]
        impl $crate::client::Client for $crate::client::$client {
            client_common_fns!();

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

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

#[macro_export]
macro_rules! config_get_fn {
    ($field_name:ident, $fn_name:ident) => {
        fn $fn_name(&self) -> anyhow::Result<String> {
            let api_key = self.config.$field_name.clone();
            api_key
                .or_else(|| {
                    let env_prefix = Self::name(&self.config);
                    let env_name =
                        format!("{}_{}", env_prefix, stringify!($field_name)).to_ascii_uppercase();
                    std::env::var(&env_name).ok()
                })
                .ok_or_else(|| {
                    anyhow::anyhow!("Miss '{}' in client configuration", stringify!($field_name))
                })
        }
    };
}

#[macro_export]
macro_rules! list_models_fn {
    ($config:ident) => {
        pub fn list_models(local_config: &$config) -> Vec<Model> {
            let client_name = Self::name(local_config);
            Model::from_config(client_name, &local_config.models)
        }
    };
    ($config:ident, [$(($name:literal, $capabilities:literal, $max_input_tokens:literal $(, $max_output_tokens:literal)? )),+$(,)?]) => {
        pub fn list_models(local_config: &$config) -> Vec<Model> {
            let client_name = Self::name(local_config);
            if local_config.models.is_empty() {
                vec![
                    $(
                        Model::new(client_name, $name)
                            .set_capabilities($capabilities.into())
                            .set_max_input_tokens(Some($max_input_tokens))
                            $(.set_max_output_tokens(Some($max_output_tokens)))?
                    ),+
                ]
            } else {
                Model::from_config(client_name, &local_config.models)
            }
        }
    };
}

#[macro_export]
macro_rules! unsupported_model {
    ($name:expr) => {
        anyhow::bail!("Unsupported model '{}'", $name)
    };
}

#[async_trait]
pub trait Client: Sync + Send {
    fn config(&self) -> (&GlobalConfig, &Option<ExtraConfig>);

    fn list_models(&self) -> Vec<Model>;

    fn model(&self) -> &Model;

    fn set_model(&mut self, model: Model);

    fn build_client(&self) -> Result<ReqwestClient> {
        let mut builder = ReqwestClient::builder();
        let options = self.config().1;
        let timeout = options
            .as_ref()
            .and_then(|v| v.connect_timeout)
            .unwrap_or(10);
        let proxy = options.as_ref().and_then(|v| v.proxy.clone());
        builder = set_proxy(builder, &proxy)?;
        let client = builder
            .connect_timeout(Duration::from_secs(timeout))
            .build()
            .with_context(|| "Failed to build client")?;
        Ok(client)
    }

    async fn send_message(&self, input: Input) -> Result<String> {
        let global_config = self.config().0;
        if global_config.read().dry_run {
            let content = global_config.read().echo_messages(&input);
            return Ok(content);
        }
        let client = self.build_client()?;
        let data = global_config.read().prepare_send_data(&input, false)?;
        self.send_message_inner(&client, data)
            .await
            .with_context(|| "Failed to get answer")
    }

    async fn send_message_streaming(
        &self,
        input: &Input,
        handler: &mut ReplyHandler,
    ) -> Result<()> {
        async fn watch_abort(abort: AbortSignal) {
            loop {
                if abort.aborted() {
                    break;
                }
                sleep(Duration::from_millis(100)).await;
            }
        }
        let abort = handler.get_abort();
        let input = input.clone();
        tokio::select! {
            ret = async {
                let global_config = self.config().0;
                if global_config.read().dry_run {
                    let content = global_config.read().echo_messages(&input);
                    let tokens = tokenize(&content);
                    for token in tokens {
                        tokio::time::sleep(Duration::from_millis(10)).await;
                        handler.text(&token)?;
                    }
                    return Ok(());
                }
                let client = self.build_client()?;
                let data = global_config.read().prepare_send_data(&input, true)?;
                self.send_message_streaming_inner(&client, handler, data).await
            } => {
                handler.done()?;
                ret.with_context(|| "Failed to get answer")
            }
            _ = watch_abort(abort.clone()) => {
                handler.done()?;
                Ok(())
            },
        }
    }

    async fn send_message_inner(&self, client: &ReqwestClient, data: SendData) -> Result<String>;

    async fn send_message_streaming_inner(
        &self,
        client: &ReqwestClient,
        handler: &mut ReplyHandler,
        data: SendData,
    ) -> Result<()>;
}

impl Default for ClientConfig {
    fn default() -> Self {
        Self::OpenAIConfig(OpenAIConfig::default())
    }
}

#[derive(Debug, Clone, Deserialize, Default)]
pub struct ExtraConfig {
    pub proxy: Option<String>,
    pub connect_timeout: Option<u64>,
}

#[derive(Debug)]
pub struct SendData {
    pub messages: Vec<Message>,
    pub temperature: Option<f64>,
    pub top_p: Option<f64>,
    pub stream: bool,
}

pub type PromptType<'a> = (&'a str, &'a str, bool, PromptKind);

pub fn create_config(list: &[PromptType], client: &str) -> Result<(String, Value)> {
    let mut config = json!({
        "type": client,
    });
    let mut model = client.to_string();
    for (path, desc, required, kind) in list {
        match kind {
            PromptKind::String => {
                let value = prompt_input_string(desc, *required)?;
                set_config_value(&mut config, path, kind, &value);
                if *path == "name" {
                    model = value;
                }
            }
            PromptKind::Integer => {
                let value = prompt_input_integer(desc, *required)?;
                set_config_value(&mut config, path, kind, &value);
            }
        }
    }

    let clients = json!(vec![config]);
    Ok((model, clients))
}

pub async fn send_stream(
    input: &Input,
    client: &dyn Client,
    config: &GlobalConfig,
    abort: AbortSignal,
) -> Result<String> {
    let (tx, rx) = unbounded_channel();
    let mut stream_handler = ReplyHandler::new(tx, abort.clone());

    let (send_ret, rend_ret) = tokio::join!(
        client.send_message_streaming(input, &mut stream_handler),
        render_stream(rx, config, abort.clone()),
    );
    if let Err(err) = rend_ret {
        render_error(err, config.read().highlight);
    }
    let output = stream_handler.get_buffer().to_string();
    match send_ret {
        Ok(_) => {
            println!();
            Ok(output)
        }
        Err(err) => {
            if !output.is_empty() {
                println!();
            }
            Err(err)
        }
    }
}

#[allow(unused)]
pub async fn send_message_as_streaming<F, Fut>(
    builder: RequestBuilder,
    handler: &mut ReplyHandler,
    f: F,
) -> Result<()>
where
    F: FnOnce(RequestBuilder) -> Fut,
    Fut: Future<Output = Result<String>>,
{
    let text = f(builder).await?;
    handler.text(&text)?;
    handler.done()?;

    Ok(())
}

pub fn catch_error(data: &Value, status: u16) -> Result<()> {
    if (200..300).contains(&status) {
        return Ok(());
    }
    debug!("Invalid response, status: {status}, data: {data}");
    if let Some(error) = data["error"].as_object() {
        if let (Some(typ), Some(message)) = (error["type"].as_str(), error["message"].as_str()) {
            bail!("{message} (type: {typ})");
        }
    } else if let Some(error) = data[0]["error"].as_object() {
        if let (Some(status), Some(message)) = (error["status"].as_str(), error["message"].as_str())
        {
            bail!("{message} (status: {status})")
        }
    } else if let Some(error) = data["error"].as_str() {
        bail!("{error}");
    } else if let Some(message) = data["message"].as_str() {
        bail!("{message}");
    }
    bail!("Invalid response data: {data} (status: {status})");
}

pub fn maybe_catch_error(data: &Value) -> Result<()> {
    if let (Some(code), Some(message)) = (data["code"].as_str(), data["message"].as_str()) {
        debug!("Invalid response: {}", data);
        bail!("{message} (code: {code})");
    } else if let (Some(error_code), Some(error_msg)) =
        (data["error_code"].as_number(), data["error_msg"].as_str())
    {
        debug!("Invalid response: {}", data);
        bail!("{error_msg} (error_code: {error_code})");
    }
    Ok(())
}

pub async fn json_stream<S, F>(mut stream: S, mut handle: F) -> Result<()>
where
    S: Stream<Item = Result<bytes::Bytes, reqwest::Error>> + Unpin,
    F: FnMut(&str) -> Result<()>,
{
    let mut buffer = vec![];
    let mut cursor = 0;
    let mut start = 0;
    let mut balances = vec![];
    let mut quoting = false;
    let mut escape = false;
    while let Some(chunk) = stream.next().await {
        let chunk = chunk?;
        let chunk = std::str::from_utf8(&chunk)?;
        buffer.extend(chunk.chars());
        for i in cursor..buffer.len() {
            let ch = buffer[i];
            if quoting {
                if ch == '\\' {
                    escape = !escape;
                } else {
                    if !escape && ch == '"' {
                        quoting = false;
                    }
                    escape = false;
                }
                continue;
            }
            match ch {
                '"' => {
                    quoting = true;
                    escape = false;
                }
                '{' => {
                    if balances.is_empty() {
                        start = i;
                    }
                    balances.push(ch);
                }
                '[' => {
                    if start != 0 {
                        balances.push(ch);
                    }
                }
                '}' => {
                    balances.pop();
                    if balances.is_empty() {
                        let value: String = buffer[start..=i].iter().collect();
                        handle(&value)?;
                    }
                }
                ']' => {
                    balances.pop();
                }
                _ => {}
            }
        }
        cursor = buffer.len();
    }
    Ok(())
}

fn set_config_value(json: &mut Value, path: &str, kind: &PromptKind, value: &str) {
    let segs: Vec<&str> = path.split('.').collect();
    match segs.as_slice() {
        [name] => json[name] = to_json(kind, value),
        [scope, name] => match scope.split_once('[') {
            None => {
                if json.get(scope).is_none() {
                    let mut obj = json!({});
                    obj[name] = to_json(kind, value);
                    json[scope] = obj;
                } else {
                    json[scope][name] = to_json(kind, value);
                }
            }
            Some((scope, _)) => {
                if json.get(scope).is_none() {
                    let mut obj = json!({});
                    obj[name] = to_json(kind, value);
                    json[scope] = json!([obj]);
                } else {
                    json[scope][0][name] = to_json(kind, value);
                }
            }
        },
        _ => {}
    }
}

fn to_json(kind: &PromptKind, value: &str) -> Value {
    if value.is_empty() {
        return Value::Null;
    }
    match kind {
        PromptKind::String => value.into(),
        PromptKind::Integer => match value.parse::<i32>() {
            Ok(value) => value.into(),
            Err(_) => value.into(),
        },
    }
}

fn set_proxy(builder: ClientBuilder, proxy: &Option<String>) -> Result<ClientBuilder> {
    let proxy = if let Some(proxy) = proxy {
        if proxy.is_empty() || proxy == "false" || proxy == "-" {
            return Ok(builder);
        }
        proxy.clone()
    } else if let Ok(proxy) = env::var("HTTPS_PROXY").or_else(|_| env::var("ALL_PROXY")) {
        proxy
    } else {
        return Ok(builder);
    };
    let builder =
        builder.proxy(Proxy::all(&proxy).with_context(|| format!("Invalid proxy `{proxy}`"))?);
    Ok(builder)
}