/// Single shard Client
use crate::pb::generate::v2::text_generation_service_client::TextGenerationServiceClient;
use crate::pb::generate::v2::*;
use crate::Result;
use grpc_metadata::InjectTelemetryContext;
use std::cmp::min;
use tonic::transport::{Channel, Uri};
use tracing::instrument;

/// Text Generation Inference gRPC client
#[derive(Debug, Clone)]
pub struct Client {
    stub: TextGenerationServiceClient<Channel>,
}

impl Client {
    /// Returns a client connected to the given url
    pub async fn connect(uri: Uri) -> Result<Self> {
        let channel = Channel::builder(uri).connect().await?;

        Ok(Self {
            stub: TextGenerationServiceClient::new(channel),
        })
    }

    /// Returns a client connected to the given unix socket
    pub async fn connect_uds(path: String) -> Result<Self> {
        let channel = Channel::from_shared("http://[::]:50051".to_string())
            .unwrap()
            .connect_with_connector(tower::service_fn(move |_: Uri| {
                tokio::net::UnixStream::connect(path.clone())
            }))
            .await?;

        Ok(Self {
            stub: TextGenerationServiceClient::new(channel),
        })
    }

    /// Returns a list of uris or unix sockets of all shards
    #[instrument(skip(self))]
    pub async fn service_discovery(&mut self) -> Result<Vec<String>> {
        let request = tonic::Request::new(ServiceDiscoveryRequest {}).inject_context();
        let response = self.stub.service_discovery(request).await?;
        let urls = response
            .into_inner()
            .urls
            .into_iter()
            // Remove unix socket prefix
            .map(|url| match url.strip_prefix("unix://") {
                None => url,
                Some(stripped_url) => stripped_url.to_string(),
            })
            .collect();
        Ok(urls)
    }

    /// Get model info
    #[instrument(skip(self))]
    pub async fn info(&mut self) -> Result<InfoResponse> {
        let request = tonic::Request::new(InfoRequest {}).inject_context();
        let response = self.stub.info(request).await?.into_inner();
        Ok(response)
    }

    /// Get model health
    #[instrument(skip(self))]
    pub async fn health(&mut self) -> Result<HealthResponse> {
        let request = tonic::Request::new(HealthRequest {}).inject_context();
        let response = self.stub.health(request).await?.into_inner();
        Ok(response)
    }

    /// Clear the past generations cache
    #[instrument(skip(self))]
    pub async fn clear_cache(&mut self, batch_id: Option<u64>) -> Result<()> {
        let request = tonic::Request::new(ClearCacheRequest { id: batch_id }).inject_context();
        self.stub.clear_cache(request).await?;
        Ok(())
    }

    /// Filter a cached batch
    #[instrument(skip(self))]
    pub async fn filter_batch(
        &mut self,
        batch_id: u64,
        request_ids: Vec<u64>,
    ) -> Result<Option<CachedBatch>> {
        let request = tonic::Request::new(FilterBatchRequest {
            batch_id,
            request_ids,
        })
        .inject_context();
        let filtered_batch = self.stub.filter_batch(request).await?.into_inner();
        Ok(filtered_batch.batch)
    }

    /// Warmup on a max size batch
    ///
    /// Returns the maximum amount of tokens supported by the hardware
    #[instrument(skip_all)]
    pub async fn warmup(
        &mut self,
        max_input_length: u32,
        max_prefill_tokens: u32,
        max_total_tokens: u32,
    ) -> Result<Option<u32>> {
        let mut n_tokens = 0;
        let mut requests = Vec::new();
        // Create requests
        while n_tokens < max_prefill_tokens {
            let truncate = min(max_input_length, max_prefill_tokens - n_tokens);
            requests.push(Request {
                id: 0,
                // We truncate the input on the server side to be sure that it has the correct size
                inputs: "_test ".to_string().repeat(max_input_length as usize),
                truncate,
                // Set sampling parameters to also take these ops into account in the max memory
                parameters: Some(NextTokenChooserParameters {
                    temperature: 0.9,
                    top_k: 10,
                    top_p: 0.9,
                    typical_p: 0.9,
                    do_sample: false,
                    seed: 0,
                    repetition_penalty: 1.2,
                    watermark: true,
                }),
                stopping_parameters: Some(StoppingCriteriaParameters {
                    max_new_tokens: max_total_tokens - truncate,
                    stop_sequences: vec![],
                    ignore_eos_token: true,
                }),
                prefill_logprobs: true,
                top_n_tokens: 20,
            });
            n_tokens += max_input_length;
        }

        let batch = Batch {
            id: 0,
            size: requests.len() as u32,
            requests,
            max_tokens: 0,
        };

        let request = tonic::Request::new(WarmupRequest { batch: Some(batch) }).inject_context();
        let response = self.stub.warmup(request).await?.into_inner();
        Ok(response.max_supported_total_tokens)
    }

    /// Generate one token for each request in the given batch
    ///
    /// Returns Generation for each request in batch
    /// and the next cached batch
    #[instrument(skip_all, fields(id = &batch.id, size = &batch.size))]
    pub async fn prefill(
        &mut self,
        batch: Batch,
    ) -> Result<(Vec<Generation>, Option<CachedBatch>)> {
        let request = tonic::Request::new(PrefillRequest { batch: Some(batch) }).inject_context();
        let response = self.stub.prefill(request).await?.into_inner();
        Ok((response.generations, response.batch))
    }

    /// Generate one token for each request in the given cached batches
    ///
    /// Returns Generation for each request in batches
    /// and the next cached batch
    #[instrument(skip_all, fields(size = batches.iter().map(|batch|{batch.size}).sum::<u32>()))]
    pub async fn decode(
        &mut self,
        batches: Vec<CachedBatch>,
    ) -> Result<(Vec<Generation>, Option<CachedBatch>)> {
        let request = tonic::Request::new(DecodeRequest { batches }).inject_context();
        let response = self.stub.decode(request).await?.into_inner();
        Ok((response.generations, response.batch))
    }
}
