finance-query 2.5.0

//! Alpha Vantage API client with rate limiting.

use std::sync::Arc;
use std::time::Duration;

use reqwest::{Client, StatusCode};
use serde_json::Value;
use tracing::debug;

use crate::error::{FinanceError, Result};
use crate::rate_limiter::RateLimiter;

const AV_BASE: &str = "https://www.alphavantage.co/query";

pub(crate) struct AlphaVantageClientBuilder {
    api_key: String,
    timeout: Duration,
    base_url: Option<String>,
}

impl AlphaVantageClientBuilder {
    pub fn new(api_key: impl Into<String>) -> Self {
        Self {
            api_key: api_key.into(),
            timeout: Duration::from_secs(30),
            base_url: None,
        }
    }

    pub fn timeout(mut self, timeout: Duration) -> Self {
        self.timeout = timeout;
        self
    }

    #[cfg(test)]
    pub fn base_url(mut self, url: impl Into<String>) -> Self {
        self.base_url = Some(url.into());
        self
    }

    pub(super) fn build_with_limiter(
        self,
        limiter: Arc<RateLimiter>,
    ) -> Result<AlphaVantageClient> {
        let http = Client::builder()
            .timeout(self.timeout)
            .user_agent(format!(
                "finance-query/{} (https://github.com/Verdenroz/finance-query)",
                env!("CARGO_PKG_VERSION")
            ))
            .build()?;

        Ok(AlphaVantageClient {
            api_key: self.api_key,
            http,
            limiter,
            base_url: self.base_url.unwrap_or_else(|| AV_BASE.to_string()),
        })
    }
}

/// Alpha Vantage API client. Constructed per-call via the module singleton.
pub(crate) struct AlphaVantageClient {
    api_key: String,
    http: Client,
    limiter: Arc<RateLimiter>,
    base_url: String,
}

impl AlphaVantageClient {
    /// Execute a GET request to the Alpha Vantage API.
    ///
    /// All AV endpoints use the same base URL with `function=` and `apikey=` query params.
    /// Additional params are passed as `&[(&str, &str)]`.
    pub async fn get(&self, function: &str, params: &[(&str, &str)]) -> Result<Value> {
        self.limiter.acquire().await;

        let mut query: Vec<(&str, &str)> = vec![("function", function), ("apikey", &self.api_key)];
        query.extend_from_slice(params);

        debug!("AlphaVantage request: function={function}");
        let resp = self.http.get(&self.base_url).query(&query).send().await?;

        match resp.status() {
            StatusCode::OK => {}
            StatusCode::UNAUTHORIZED | StatusCode::FORBIDDEN => {
                return Err(FinanceError::AuthenticationFailed {
                    context: "Alpha Vantage API key invalid or missing. Call alphavantage::init(key) first.".to_string(),
                });
            }
            StatusCode::TOO_MANY_REQUESTS => {
                return Err(FinanceError::RateLimited {
                    retry_after: Some(60),
                });
            }
            s => {
                return Err(FinanceError::ExternalApiError {
                    api: "AlphaVantage".to_string(),
                    status: s.as_u16(),
                });
            }
        }

        let json: Value = resp.json().await?;

        // AV returns 200 with error messages in the JSON body
        if let Some(error_msg) = json.get("Error Message").and_then(|v| v.as_str()) {
            return Err(FinanceError::InvalidParameter {
                param: "function".to_string(),
                reason: error_msg.to_string(),
            });
        }
        if let Some(note) = json.get("Note").and_then(|v| v.as_str())
            && note.contains("call frequency")
        {
            return Err(FinanceError::RateLimited {
                retry_after: Some(60),
            });
        }
        if let Some(info) = json.get("Information").and_then(|v| v.as_str()) {
            if info.contains("rate limit") || info.contains("API call frequency") {
                return Err(FinanceError::RateLimited {
                    retry_after: Some(60),
                });
            }
            // Premium endpoint, invalid key, or other AV informational message.
            return Err(FinanceError::ApiError(format!("AlphaVantage: {info}")));
        }

        Ok(json)
    }

    /// Execute a GET request that returns CSV data (for calendar endpoints).
    pub async fn get_csv(&self, function: &str, params: &[(&str, &str)]) -> Result<String> {
        self.limiter.acquire().await;

        let mut query: Vec<(&str, &str)> = vec![("function", function), ("apikey", &self.api_key)];
        query.extend_from_slice(params);

        debug!("AlphaVantage CSV request: function={function}");
        let resp = self.http.get(&self.base_url).query(&query).send().await?;

        match resp.status() {
            StatusCode::OK => {}
            StatusCode::UNAUTHORIZED | StatusCode::FORBIDDEN => {
                return Err(FinanceError::AuthenticationFailed {
                    context: "Alpha Vantage API key invalid or missing.".to_string(),
                });
            }
            StatusCode::TOO_MANY_REQUESTS => {
                return Err(FinanceError::RateLimited {
                    retry_after: Some(60),
                });
            }
            s => {
                return Err(FinanceError::ExternalApiError {
                    api: "AlphaVantage".to_string(),
                    status: s.as_u16(),
                });
            }
        }

        Ok(resp.text().await?)
    }
}