//! CAS Engine 错误类型定义

use thiserror::Error;

/// CAS Engine 错误类型
#[derive(Error, Debug)]
pub enum CasError {
    /// IO 错误
    #[error("IO error: {0}")]
    Io(#[from] std::io::Error),

    /// Hash 不匹配
    #[error("Hash mismatch: expected {expected}, got {actual}")]
    HashMismatch {
        /// 期望的 Hash
        expected: String,
        /// 实际的 Hash
        actual: String,
    },

    /// 对象不存在
    #[error("Object not found: {0}")]
    ObjectNotFound(String),

    /// Hash 格式无效
    #[error("Invalid hash: {0}")]
    InvalidHash(String),

    /// 引用计数下溢
    #[error("Reference count is already zero: {0}")]
    ReferenceUnderflow(String),

    /// 数据库错误
    #[error("Database error: {0}")]
    Database(String),

    /// 其他错误
    #[error(transparent)]
    Other(#[from] anyhow::Error),
}

/// CAS Engine Result 类型
pub type Result<T> = std::result::Result<T, CasError>;

impl From<sqlx::Error> for CasError {
    fn from(error: sqlx::Error) -> Self {
        Self::Database(error.to_string())
    }
}