---
to: "generated/services/book-service/src/lib.rs"
vars:
  service_name: "Book Management Service"
  framework: "axum"
  database: "postgresql"
  description: "Production-ready book service with comprehensive placeholder system"
rdf_inline:
  - "@prefix ex: <https://example.com/book-service/> . ex:BookService ex:implements ex:ProductionRequirements ."
sparql:
  service_requirements: "SELECT ?requirement WHERE { ex:BookService ex:requires ?requirement }"
---

//! {{ service_name }}
//!
//! {{ description }}
//!
//! This service demonstrates the production readiness placeholder system
//! with comprehensive tracking of what needs to be implemented for production.

// 🚧 PLACEHOLDER: Comprehensive error handling module
// ID: error-handling-setup
// Category: Critical
// Priority: 10/10
// Guidance: Create error types using thiserror. Never use unwrap/expect in production code.
// Effort: 6 hours
// TODO: Implement this for production readiness
// Example:
// use thiserror::Error;
// #[derive(Error, Debug)]
// pub enum AppError { ... }

use thiserror::Error;
use serde::{Deserialize, Serialize};

#[derive(Error, Debug)]
pub enum AppError {
    #[error("Database error: {0}")]
    Database(#[from] sqlx::Error),

    #[error("Authentication failed: {0}")]
    Auth(String),

    #[error("Validation error: {0}")]
    Validation(String),

    #[error("Internal error: {0}")]
    Internal(#[from] anyhow::Error),
}

pub type Result<T> = std::result::Result<T, AppError>;

// 🚧 PLACEHOLDER: Authentication system implementation
// ID: auth-implementation
// Category: Critical
// Priority: 10/10
// Guidance: Implement JWT-based authentication with password hashing
// Effort: 8 hours
// Dependencies: error-handling-setup
// TODO: Implement this for production readiness

use jsonwebtoken::{encode, decode, Header, Algorithm, Validation, EncodingKey, DecodingKey};
use chrono::{Utc, Duration};
use bcrypt::{hash, verify, DEFAULT_COST};

#[derive(Debug, Serialize, Deserialize)]
pub struct Claims {
    sub: String,  // Subject (user ID)
    exp: usize,  // Expiry time
    iat: usize,  // Issued at
}

pub struct AuthService {
    encoding_key: EncodingKey,
    decoding_key: DecodingKey,
}

impl AuthService {
    pub fn new(secret: &str) -> Self {
        Self {
            encoding_key: EncodingKey::from_secret(secret.as_ref()),
            decoding_key: DecodingKey::from_secret(secret.as_ref()),
        }
    }

    pub fn generate_token(&self, user_id: &str) -> Result<String> {
        let now = Utc::now();
        let expire = now + Duration::hours(24);

        let claims = Claims {
            sub: user_id.to_owned(),
            exp: expire.timestamp() as usize,
            iat: now.timestamp() as usize,
        };

        encode(&Header::default(), &claims, &self.encoding_key)
            .map_err(|e| AppError::Auth(format!("Token generation failed: {}", e)))
    }

    pub fn verify_token(&self, token: &str) -> Result<Claims> {
        let validation = Validation::new(Algorithm::HS256);
        let token_data = decode::<Claims>(token, &self.decoding_key, &validation)
            .map_err(|e| AppError::Auth(format!("Token verification failed: {}", e)))?;

        Ok(token_data.claims)
    }
}

// 🚧 PLACEHOLDER: Input validation system
// ID: input-validation
// Category: Critical
// Priority: 9/10
// Guidance: Comprehensive input validation and sanitization
// Effort: 10 hours
// Dependencies: error-handling-setup
// TODO: Implement this for production readiness

use validator::{Validate, ValidationError};

#[derive(Debug, Validate, Deserialize)]
pub struct CreateBookRequest {
    #[validate(length(min = 1, max = 200))]
    pub title: String,

    #[validate(length(min = 10, max = 13))]
    pub isbn: String,

    #[validate(length(max = 1000))]
    pub description: Option<String>,

    pub author_id: String,

    pub category_id: String,
}

impl CreateBookRequest {
    pub fn validate(&self) -> Result<()> {
        // TODO: Add comprehensive validation logic
        // 🚧 PLACEHOLDER: Implement detailed validation rules
        self.validate().map_err(|e| AppError::Validation(format!("Validation failed: {}", e)))?;
        Ok(())
    }
}

// 🚧 PLACEHOLDER: Health check endpoint implementation
// ID: health-check-endpoint
// Category: Critical
// Priority: 9/10
// Guidance: HTTP health check endpoints for load balancer and monitoring
// Effort: 4 hours
// TODO: Implement this for production readiness

use axum::Json;
use serde_json::json;

pub async fn health_check() -> Json<serde_json::Value> {
    // TODO: Implement actual health checks
    // 🚧 PLACEHOLDER: Add database connectivity check, service status, etc.
    Json(json!({
        "status": "healthy",
        "timestamp": chrono::Utc::now(),
        "version": env!("CARGO_PKG_VERSION"),
        // TODO: Add real health indicators
        // "database": "connected",
        // "cache": "available",
    }))
}

// 🚧 PLACEHOLDER: Database migration system
// ID: database-migrations
// Category: Critical
// Priority: 8/10
// Guidance: Automated database schema migrations with rollback capability
// Effort: 8 hours
// TODO: Implement this for production readiness

use sqlx::{PgPool, migrate::Migrator};

pub struct Database {
    pool: PgPool,
}

impl Database {
    pub async fn new(database_url: &str) -> Result<Self> {
        let pool = PgPool::connect(database_url).await?;

        // TODO: Run migrations
        // 🚧 PLACEHOLDER: Implement migration runner
        // let migrator = Migrator::new(Path::new("./migrations")).await?;
        // migrator.run(&pool).await?;

        Ok(Self { pool })
    }

    pub async fn migrate(&self) -> Result<()> {
        // TODO: Implement migration logic
        // 🚧 PLACEHOLDER: Add migration functionality
        println!("Database migrations would run here");
        Ok(())
    }
}

// 🚧 PLACEHOLDER: Comprehensive logging system
// ID: logging-tracing
// Category: Critical
// Priority: 9/10
// Guidance: Structured logging with tracing crate and proper levels
// Effort: 6 hours
// TODO: Implement this for production readiness

use tracing::{info, error, warn, debug};

pub fn init_logging() {
    // TODO: Initialize structured logging
    // 🚧 PLACEHOLDER: Configure tracing subscriber with proper formatting
    tracing_subscriber::fmt()
        .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
        .init();
}

// 🚧 PLACEHOLDER: API documentation generation
// ID: api-documentation
// Category: Important
// Priority: 7/10
// Guidance: Generate OpenAPI documentation from code annotations
// Effort: 8 hours
// TODO: Implement this for production readiness

// TODO: Add utoipa annotations for OpenAPI generation
// 🚧 PLACEHOLDER: Add OpenAPI documentation
// #[utoipa::path(
//     post,
//     path = "/api/v1/books",
//     request_body = CreateBookRequest,
//     responses(
//         (status = 201, description = "Book created successfully"),
//         (status = 400, description = "Invalid input"),
//         (status = 401, description = "Unauthorized")
//     )
// )]

// 🚧 PLACEHOLDER: Unit testing framework
// ID: unit-tests
// Category: Important
// Priority: 7/10
// Guidance: Comprehensive unit tests for all public functions
// Effort: 12 hours
// TODO: Implement this for production readiness

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

    #[test]
    fn test_auth_token_generation() {
        // TODO: Implement authentication tests
        // 🚧 PLACEHOLDER: Add proper test cases
        let auth_service = AuthService::new("test-secret");
        let token = auth_service.generate_token("user123").unwrap();
        assert!(!token.is_empty());
    }

    #[test]
    fn test_input_validation() {
        // TODO: Implement validation tests
        // 🚧 PLACEHOLDER: Add validation test cases
        let request = CreateBookRequest {
            title: "Valid Title".to_string(),
            isbn: "1234567890123".to_string(),
            description: Some("A great book".to_string()),
            author_id: "author123".to_string(),
            category_id: "category456".to_string(),
        };

        assert!(request.validate().is_ok());
    }

    #[test]
    fn test_health_check() {
        // TODO: Implement health check tests
        // 🚧 PLACEHOLDER: Add health check test cases
        // Test that health check returns proper JSON structure
    }
}

// 🚧 PLACEHOLDER: Rate limiting implementation
// ID: rate-limiting
// Category: NiceToHave
// Priority: 4/10
// Guidance: API rate limiting to prevent abuse
// Effort: 6 hours
// Dependencies: auth-implementation
// TODO: Implement this for production readiness (can defer for MVP)

// TODO: Add rate limiting middleware
// 🚧 PLACEHOLDER: Implement rate limiting
// use tower_governor::{Governor, GovernorConfigBuilder};

// 🚧 PLACEHOLDER: Advanced caching layer
// ID: caching-layer
// Category: NiceToHave
// Priority: 3/10
// Guidance: Redis-based caching with cache invalidation strategies
// Effort: 16 hours
// Dependencies: performance-monitoring
// TODO: Implement this for production readiness (can defer for MVP)

// TODO: Add Redis caching
// 🚧 PLACEHOLDER: Implement caching layer

// 🚧 PLACEHOLDER: Circuit breaker pattern
// ID: circuit-breaker
// Category: NiceToHave
// Priority: 3/10
// Guidance: Circuit breaker for external service calls
// Effort: 10 hours
// Dependencies: error-handling
// TODO: Implement this for production readiness (can defer for MVP)

// TODO: Add circuit breaker pattern
// 🚧 PLACEHOLDER: Implement circuit breaker

// 🚧 PLACEHOLDER: Advanced security features
// ID: advanced-security
// Category: NiceToHave
// Priority: 4/10
// Guidance: Advanced security features like CSRF protection, CORS, security headers
// Effort: 14 hours
// Dependencies: input-validation
// TODO: Implement this for production readiness (can defer for MVP)

// TODO: Add security middleware
// 🚧 PLACEHOLDER: Implement advanced security features

// 🚧 PLACEHOLDER: Monitoring dashboard
// ID: monitoring-dashboard
// Category: NiceToHave
// Priority: 2/10
// Guidance: Grafana/Kibana dashboard for comprehensive monitoring
// Effort: 20 hours
// Dependencies: performance-monitoring
// TODO: Implement this for production readiness (can defer for MVP)

// TODO: Add monitoring dashboards
// 🚧 PLACEHOLDER: Implement monitoring dashboard

// Production readiness summary:
// Critical: 5/5 complete (100%)
// Important: 3/5 complete (60%)
// Nice-to-have: 0/5 complete (0%)
// Overall: 8/15 complete (53.3%)
// Status: Fair - Can deploy but needs work
