use crate::domain::error::{AppError, AppResult};
use crate::domain::models::{Customer, CustomerProfile, OrderRecord};
use crate::infrastructure::db::DbPool;
use argon2::{
    password_hash::{PasswordHash, PasswordHasher, PasswordVerifier, SaltString},
    Argon2,
};
use async_trait::async_trait;
use jsonwebtoken::{encode, EncodingKey, Header};
use serde::{Deserialize, Serialize};
#[allow(unused_imports)]
use std::sync::Arc;
use uuid::Uuid;

#[derive(Debug, Serialize, Deserialize)]
pub struct CustomerClaims {
    pub sub: String, // customer_id
    pub phone: String,
    pub role: String,
    pub exp: usize,
}

#[async_trait]
pub trait CustomerService: Send + Sync {
    async fn signup(
        &self,
        phone: &str,
        password: &str,
        name: Option<&str>,
        email: Option<&str>,
    ) -> AppResult<String>;
    async fn login(&self, phone: &str, password: &str) -> AppResult<String>;
    async fn get_orders(
        &self,
        customer_id: &str,
        merchant_id: Option<&str>,
    ) -> AppResult<Vec<OrderRecord>>;
    async fn get_profile(&self, customer_id: &str) -> AppResult<Option<CustomerProfile>>;
}

pub struct RtixCustomerService {
    pool: DbPool,
    jwt_secret: Vec<u8>,
}

impl RtixCustomerService {
    pub fn new(pool: DbPool, jwt_secret: Vec<u8>) -> Self {
        Self { pool, jwt_secret }
    }

    fn hash_password(&self, password: &str) -> AppResult<String> {
        let salt = SaltString::generate(&mut rand::thread_rng());
        Argon2::default()
            .hash_password(password.as_bytes(), &salt)
            .map(|h| h.to_string())
            .map_err(|e| AppError::Internal(format!("Hashing failed: {}", e)))
    }

    fn verify_password(&self, password: &str, hash: &str) -> AppResult<()> {
        let parsed_hash = PasswordHash::new(hash)
            .map_err(|_| AppError::Internal("Invalid hash stored".to_string()))?;
        Argon2::default()
            .verify_password(password.as_bytes(), &parsed_hash)
            .map_err(|_| AppError::Auth("Invalid credentials".to_string()))
    }
}

#[async_trait]
impl CustomerService for RtixCustomerService {
    async fn signup(
        &self,
        phone: &str,
        password: &str,
        name: Option<&str>,
        email: Option<&str>,
    ) -> AppResult<String> {
        let password_hash = self.hash_password(password)?;
        let customer_id = Uuid::new_v4().to_string();

        let res = sqlx::query(
            "INSERT INTO customers (customer_id, phone, name, email, password_hash) VALUES ($1, $2, $3, $4, $5) ON CONFLICT (phone) DO NOTHING"
        )
        .bind(&customer_id)
        .bind(phone)
        .bind(name)
        .bind(email)
        .bind(password_hash)
        .execute(&self.pool)
        .await?;

        if res.rows_affected() == 0 {
            return Err(AppError::Conflict(
                "An account with this phone number already exists".into(),
            ));
        }

        Ok(customer_id)
    }

    async fn login(&self, phone: &str, password: &str) -> AppResult<String> {
        let customer =
            sqlx::query_as::<_, Customer>("SELECT * FROM customers WHERE phone = $1 OR email = $1")
                .bind(phone)
                .fetch_optional(&self.pool)
                .await?
                .ok_or_else(|| AppError::Auth("Invalid credentials".into()))?;

        self.verify_password(password, &customer.password_hash)?;

        let exp = (chrono::Utc::now() + chrono::Duration::days(7)).timestamp() as usize;
        let claims = CustomerClaims {
            sub: customer.customer_id.clone(),
            phone: customer.phone.clone(),
            role: "customer".into(),
            exp,
        };

        let token = encode(
            &Header::default(),
            &claims,
            &EncodingKey::from_secret(&self.jwt_secret),
        )
        .map_err(|_| AppError::Internal("Token generation failed".into()))?;

        Ok(token)
    }

    async fn get_orders(
        &self,
        customer_id: &str,
        merchant_id: Option<&str>,
    ) -> AppResult<Vec<OrderRecord>> {
        use crate::core::crypto::CryptoService;
        use sqlx::Row;

        // 1. Retrieve the customer's plaintext phone number from the auth table
        let row = sqlx::query("SELECT phone FROM customers WHERE customer_id = $1")
            .bind(customer_id)
            .fetch_optional(&self.pool)
            .await?
            .ok_or_else(|| AppError::NotFound("Customer not found".into()))?;
        let target_phone: String = row.get("phone");

        // 2. Compute a deterministic HMAC-SHA256 blind index of the phone number.
        //    This allows an O(1) indexed DB lookup without exposing PII in the query.
        let phone_hash = CryptoService::deterministic_hash(&target_phone);

        // 3. Run an indexed query — hit buyer_phone_hash directly, no full-table scan.
        let raw_orders: Vec<OrderRecord> = if let Some(m_id) = merchant_id {
            sqlx::query_as::<_, OrderRecord>(
                "SELECT o.*, m.brand_name FROM orders o LEFT JOIN merchants m ON o.merchant_id = m.merchant_id WHERE o.buyer_phone_hash = $1 AND o.merchant_id = $2 ORDER BY o.created_at DESC",
            )
            .bind(&phone_hash)
            .bind(m_id)
            .fetch_all(&self.pool)
            .await?
        } else {
            sqlx::query_as::<_, OrderRecord>(
                "SELECT o.*, m.brand_name FROM orders o LEFT JOIN merchants m ON o.merchant_id = m.merchant_id WHERE o.buyer_phone_hash = $1 ORDER BY o.created_at DESC",
            )
            .bind(&phone_hash)
            .fetch_all(&self.pool)
            .await?
        };

        // 4. Decrypt only the matched rows (typically a very small set per customer)
        let matched_orders = raw_orders
            .into_iter()
            .map(|mut order| {
                order.decrypt_pii();
                if order.vpa.as_deref() == Some("") {
                    order.vpa = None;
                }
                order
            })
            .collect();

        Ok(matched_orders)
    }

    async fn get_profile(&self, customer_id: &str) -> AppResult<Option<CustomerProfile>> {
        let profile = sqlx::query_as::<_, CustomerProfile>(
            "SELECT customer_id, phone, email, name FROM customers WHERE customer_id = $1",
        )
        .bind(customer_id)
        .fetch_optional(&self.pool)
        .await?;
        Ok(profile)
    }
}