ai_synth/backend/src/models/rate_limit.rs

//! Admin rate limit model and request/response types.
//!
//! Per-provider rate limit configuration managed by admins.
//! Controls the maximum number of API requests allowed within
//! a sliding time window for each LLM provider.

use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use uuid::Uuid;

/// An admin rate limit record from the database.
#[derive(Debug, Clone, Serialize)]
pub struct AdminRateLimit {
    pub id: Uuid,
    pub provider_name: String,
    pub max_requests: i32,
    pub time_window_seconds: i32,
    pub updated_at: DateTime<Utc>,
}

/// Request body for `PUT /api/v1/admin/rate-limits/:provider_name`.
#[derive(Debug, Deserialize)]
pub struct UpdateRateLimitRequest {
    pub max_requests: i32,
    pub time_window_seconds: i32,
}

impl UpdateRateLimitRequest {
    /// Validate the rate limit update request.
    ///
    /// - `max_requests` must be between 1 and 1000.
    /// - `time_window_seconds` must be between 1 and 3600.
    pub fn validate(&self) -> Result<(), String> {
        if self.max_requests < 1 || self.max_requests > 1000 {
            return Err("max_requests must be between 1 and 1000".into());
        }
        if self.time_window_seconds < 1 || self.time_window_seconds > 3600 {
            return Err("time_window_seconds must be between 1 and 3600".into());
        }
        Ok(())
    }
}

/// Response shape for rate limit endpoints.
#[derive(Debug, Serialize)]
pub struct RateLimitResponse {
    pub id: Uuid,
    pub provider_name: String,
    pub max_requests: i32,
    pub time_window_seconds: i32,
    pub updated_at: DateTime<Utc>,
}

impl From<AdminRateLimit> for RateLimitResponse {
    fn from(rl: AdminRateLimit) -> Self {
        Self {
            id: rl.id,
            provider_name: rl.provider_name,
            max_requests: rl.max_requests,
            time_window_seconds: rl.time_window_seconds,
            updated_at: rl.updated_at,
        }
    }
}

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

    #[test]
    fn test_valid_rate_limit_request() {
        let req = UpdateRateLimitRequest {
            max_requests: 30,
            time_window_seconds: 60,
        };
        assert!(req.validate().is_ok());
    }

    #[test]
    fn test_max_requests_too_low() {
        let req = UpdateRateLimitRequest {
            max_requests: 0,
            time_window_seconds: 60,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("max_requests"));
    }

    #[test]
    fn test_max_requests_too_high() {
        let req = UpdateRateLimitRequest {
            max_requests: 1001,
            time_window_seconds: 60,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("max_requests"));
    }

    #[test]
    fn test_time_window_too_low() {
        let req = UpdateRateLimitRequest {
            max_requests: 30,
            time_window_seconds: 0,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("time_window_seconds"));
    }

    #[test]
    fn test_time_window_too_high() {
        let req = UpdateRateLimitRequest {
            max_requests: 30,
            time_window_seconds: 3601,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("time_window_seconds"));
    }

    #[test]
    fn test_boundary_values() {
        let req_min = UpdateRateLimitRequest {
            max_requests: 1,
            time_window_seconds: 1,
        };
        assert!(req_min.validate().is_ok());

        let req_max = UpdateRateLimitRequest {
            max_requests: 1000,
            time_window_seconds: 3600,
        };
        assert!(req_max.validate().is_ok());
    }
}