use std::fmt;

pub const DEFAULT_API_SERVER_HEALTHZ_URL: &str = "http://127.0.0.1:3100/healthz";

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct SmokeAssertionError {
    message: String,
}

impl SmokeAssertionError {
    /// 测试支撑 crate 只提供断言辅助，不承接业务错误分类。
    pub fn new(message: impl Into<String>) -> Self {
        Self {
            message: message.into(),
        }
    }

    pub fn message(&self) -> &str {
        &self.message
    }
}

impl fmt::Display for SmokeAssertionError {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        formatter.write_str(&self.message)
    }
}

impl std::error::Error for SmokeAssertionError {}

/// 归一化本地 smoke URL，供不同测试入口复用同一套空值与斜杠处理口径。
pub fn normalize_smoke_url(input: impl AsRef<str>) -> String {
    let trimmed = input.as_ref().trim();
    if trimmed.is_empty() {
        return DEFAULT_API_SERVER_HEALTHZ_URL.to_string();
    }

    trimmed.trim_end_matches('/').to_string()
}

/// 断言 HTTP 状态码处于 2xx，避免 smoke 测试散落重复判断。
pub fn assert_success_status(status: u16) -> Result<(), SmokeAssertionError> {
    if (200..=299).contains(&status) {
        return Ok(());
    }

    Err(SmokeAssertionError::new(format!(
        "期望 HTTP 2xx 状态码，实际为 {status}"
    )))
}

/// 断言 healthz 响应体非空。具体 JSON 字段语义仍归 api-server 自己的 contract 测试负责。
pub fn assert_non_empty_healthz_body(body: impl AsRef<str>) -> Result<(), SmokeAssertionError> {
    if body.as_ref().trim().is_empty() {
        return Err(SmokeAssertionError::new("healthz 响应体不能为空"));
    }

    Ok(())
}

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

    #[test]
    fn normalize_smoke_url_uses_api_server_healthz_when_empty() {
        assert_eq!(
            normalize_smoke_url("  "),
            DEFAULT_API_SERVER_HEALTHZ_URL.to_string()
        );
    }

    #[test]
    fn normalize_smoke_url_removes_trailing_slash() {
        assert_eq!(
            normalize_smoke_url(" http://127.0.0.1:3100/ "),
            "http://127.0.0.1:3100"
        );
    }

    #[test]
    fn assert_success_status_rejects_non_2xx() {
        let error = assert_success_status(503).expect_err("非 2xx 状态码必须失败");
        assert_eq!(error.message(), "期望 HTTP 2xx 状态码，实际为 503");
    }

    #[test]
    fn assert_non_empty_healthz_body_rejects_blank_body() {
        let error = assert_non_empty_healthz_body(" \n ").expect_err("空响应体必须失败");
        assert_eq!(error.message(), "healthz 响应体不能为空");
    }
}