reasonkit-web 0.1.7

//! # API Key Management Module
//!
//! API key generation, rotation, and access control.
//!
//! ## Features
//!
//! - Scoped API keys with fine-grained permissions
//! - Automatic key rotation
//! - Usage tracking and rate limiting per key
//! - Key revocation with audit trail

#![allow(unused_variables)] // Stub implementation

use axum::{
    extract::{Json, Path},
    http::StatusCode,
    response::IntoResponse,
};
use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use uuid::Uuid;

/// API key scopes (permissions)
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, Hash)]
#[serde(rename_all = "snake_case")]
pub enum ApiKeyScope {
    /// Read reasoning results
    ReasoningRead,
    /// Execute reasoning protocols
    ReasoningWrite,
    /// Read user profile
    ProfileRead,
    /// Modify user profile
    ProfileWrite,
    /// Read settings
    SettingsRead,
    /// Modify settings
    SettingsWrite,
    /// Create exports
    ExportCreate,
    /// Full access (admin)
    Admin,
}

/// API key metadata
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ApiKey {
    /// Key ID (public identifier)
    pub id: Uuid,
    /// Key name (user-defined)
    pub name: String,
    /// Key prefix (first 8 chars for display)
    pub prefix: String,
    /// Hashed key (never expose raw key after creation)
    #[serde(skip_serializing)]
    pub key_hash: String,
    /// User ID who owns this key
    pub user_id: Uuid,
    /// Granted scopes
    pub scopes: Vec<ApiKeyScope>,
    /// Creation timestamp
    pub created_at: DateTime<Utc>,
    /// Last used timestamp
    pub last_used: Option<DateTime<Utc>>,
    /// Expiration timestamp (optional)
    pub expires_at: Option<DateTime<Utc>>,
    /// Is key active
    pub active: bool,
    /// Rate limit (requests per minute)
    pub rate_limit: Option<u32>,
    /// Total usage count
    pub usage_count: u64,
}

/// API key creation response (only time raw key is shown)
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ApiKeyCreated {
    pub id: Uuid,
    pub name: String,
    /// Raw API key - ONLY shown once at creation
    pub key: String,
    pub prefix: String,
    pub scopes: Vec<ApiKeyScope>,
    pub created_at: DateTime<Utc>,
    pub expires_at: Option<DateTime<Utc>>,
}

/// API key service for database operations
#[allow(dead_code)] // Reserved for future database validation
pub struct ApiKeyService {
    // TODO: Add database connection pool
    max_keys_per_user: usize,
}

impl ApiKeyService {
    pub fn new(max_keys_per_user: usize) -> Self {
        Self { max_keys_per_user }
    }

    /// Generate a new API key
    pub fn generate_key() -> String {
        use rand::Rng;
        let mut rng = rand::rng();
        let key: String = (0..32)
            .map(|_| {
                let idx = rng.random_range(0..62);
                "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
                    .chars()
                    .nth(idx)
                    .unwrap()
            })
            .collect();
        format!("rk_{}", key)
    }

    /// Hash an API key for storage
    pub fn hash_key(key: &str) -> String {
        use sha2::{Digest, Sha256};
        let mut hasher = Sha256::new();
        hasher.update(key.as_bytes());
        format!("{:x}", hasher.finalize())
    }

    /// Create a new API key
    pub async fn create_key(
        &self,
        user_id: Uuid,
        name: String,
        scopes: Vec<ApiKeyScope>,
        expires_at: Option<DateTime<Utc>>,
        rate_limit: Option<u32>,
    ) -> Result<ApiKeyCreated, ApiKeyError> {
        // TODO: Check user's key count
        // TODO: Store in database

        let raw_key = Self::generate_key();
        let key_hash = Self::hash_key(&raw_key);
        let prefix = raw_key[..11].to_string(); // "rk_" + 8 chars

        let created = ApiKeyCreated {
            id: Uuid::new_v4(),
            name,
            key: raw_key,
            prefix,
            scopes,
            created_at: Utc::now(),
            expires_at,
        };

        Ok(created)
    }

    /// List all keys for a user (without secrets)
    pub async fn list_keys(&self, user_id: Uuid) -> Result<Vec<ApiKey>, ApiKeyError> {
        // TODO: Query database
        Ok(vec![])
    }

    /// Revoke an API key
    pub async fn revoke_key(&self, user_id: Uuid, key_id: Uuid) -> Result<(), ApiKeyError> {
        // TODO: Update database
        Ok(())
    }

    /// Rotate an API key (revoke old, create new with same scopes)
    pub async fn rotate_key(
        &self,
        user_id: Uuid,
        key_id: Uuid,
    ) -> Result<ApiKeyCreated, ApiKeyError> {
        // TODO: Get old key, create new, revoke old
        Err(ApiKeyError::NotFound)
    }

    /// Validate an API key and return its metadata
    pub async fn validate_key(&self, raw_key: &str) -> Result<ApiKey, ApiKeyError> {
        let key_hash = Self::hash_key(raw_key);
        // TODO: Query database by hash
        Err(ApiKeyError::InvalidKey)
    }

    /// Record key usage
    pub async fn record_usage(&self, key_id: Uuid) -> Result<(), ApiKeyError> {
        // TODO: Update last_used and increment usage_count
        Ok(())
    }
}

impl Default for ApiKeyService {
    fn default() -> Self {
        Self::new(10)
    }
}

/// API key errors
#[derive(Debug, thiserror::Error)]
pub enum ApiKeyError {
    #[error("API key not found")]
    NotFound,
    #[error("Invalid API key")]
    InvalidKey,
    #[error("API key expired")]
    Expired,
    #[error("API key revoked")]
    Revoked,
    #[error("Rate limit exceeded")]
    RateLimitExceeded,
    #[error("Insufficient permissions")]
    InsufficientScope,
    #[error("Maximum keys exceeded")]
    MaxKeysExceeded,
    #[error("Database error: {0}")]
    DatabaseError(String),
}

/// HTTP handlers for API key endpoints
pub mod handlers {
    use super::*;

    #[derive(Debug, Deserialize)]
    pub struct CreateKeyRequest {
        pub name: String,
        pub scopes: Vec<ApiKeyScope>,
        #[serde(default)]
        pub expires_in_days: Option<u32>,
        pub rate_limit: Option<u32>,
    }

    /// List all API keys for current user
    pub async fn list_keys() -> impl IntoResponse {
        (StatusCode::OK, Json(serde_json::json!({"keys": []})))
    }

    /// Create a new API key
    pub async fn create_key(Json(req): Json<CreateKeyRequest>) -> impl IntoResponse {
        let raw_key = ApiKeyService::generate_key();
        let prefix = raw_key[..11].to_string();

        let response = ApiKeyCreated {
            id: Uuid::new_v4(),
            name: req.name,
            key: raw_key,
            prefix,
            scopes: req.scopes,
            created_at: Utc::now(),
            expires_at: req
                .expires_in_days
                .map(|d| Utc::now() + chrono::Duration::days(d as i64)),
        };

        (StatusCode::CREATED, Json(response))
    }

    /// Revoke an API key
    pub async fn revoke_key(Path(id): Path<Uuid>) -> impl IntoResponse {
        (
            StatusCode::OK,
            Json(serde_json::json!({"success": true, "revoked_key_id": id})),
        )
    }

    /// Rotate an API key
    pub async fn rotate_key(Path(id): Path<Uuid>) -> impl IntoResponse {
        // TODO: Implement key rotation
        StatusCode::NOT_IMPLEMENTED
    }
}