use axum::{
    Json,
    http::StatusCode,
    response::{IntoResponse, Response},
};
use serde_json::json;
use thiserror::Error;

#[derive(Error, Debug)]
pub enum StashError {
    #[error("IO 错误: {0}")]
    Io(#[from] std::io::Error),

    #[error("文件监听失败: {0}")]
    Watch(#[from] notify::Error),

    #[error("目录不存在或非法: {0}")]
    InvalidDirectory(String),

    #[error("网络地址解析失败: {0}")]
    AddrParse(#[from] std::net::AddrParseError),

    #[error("端口绑定失败: {0}")]
    ServerBind(String),

    #[error("未找到资源: {0}")]
    NotFound(String),

    /// 数据库相关失败：打开、建表、种子导入、查询。
    /// 统一收敛成一个变体，避免把 rusqlite 的类型泄漏到库的公开 API。
    #[error("数据库错误: {0}")]
    Database(String),

    /// 乐观锁冲突：资源在本次编辑期间被别人改过。
    #[error("冲突: {0}")]
    Conflict(String),
}

impl IntoResponse for StashError {
    fn into_response(self) -> Response {
        let (status, err_msg) = match self {
            StashError::NotFound(msg) => (StatusCode::NOT_FOUND, msg),
            StashError::InvalidDirectory(msg) => (StatusCode::BAD_REQUEST, msg),
            StashError::Conflict(msg) => (StatusCode::CONFLICT, msg),
            _ => (StatusCode::INTERNAL_SERVER_ERROR, self.to_string()),
        };

        let body = Json(json!({
            "error": err_msg,
            "status": status.as_u16(),
        }));

        (status, body).into_response()
    }
}