//! 网关配置(env 加载,凭证不进 git)
//!
//! 配置来源:环境变量 > 默认值(gateway.toml 文件加载为后续增强,当前未实现)。
//! u-relay token 与桌面端 df-tunnel 同源(env U_RELAY_TOKEN)。

use serde::Deserialize;

/// 网关全局配置
#[derive(Debug, Clone, Deserialize)]
pub struct GatewayConfig {
    /// u-relay WS 地址(生产 u-relay.1216.top,本地 http://127.0.0.1:9180)
    pub relay_url: String,
    /// relay 配对 token(env U_RELAY_TOKEN 同源)
    pub relay_token: String,
    /// channel 路由表:IM 侧默认走 default_channel;按前缀路由的多桌面端配置(预留项 ⑥)
    #[serde(default)]
    pub channels: Vec<ChannelRoute>,
    /// 飞书应用凭证(未配置则该平台禁用)
    #[serde(default)]
    pub feishu: Option<FeishuConfig>,
    /// TextDelta 节流窗口毫秒(默认 800,IM 频控友好)
    #[serde(default = "default_throttle_ms")]
    pub throttle_ms: u64,
    /// 用户白名单(空=放行所有,生产部署务必显式配置)
    ///
    /// 注:历史注释「空=拒绝所有」与 main.rs 实现(空=放行)矛盾,走查 2026-10-04 定为
    /// 空=放行——否则首次启动零配置时飞书/Web 全部拒绝,连 banner 警告都没有,反而
    /// 更难发现配置缺失。生产风险由 main.rs 启动 banner 常驻警告 + 白名单缺失提示兜底。
    #[serde(default)]
    pub whitelist: Vec<String>,
}

/// channel 路由项:IM 指令前缀 → 桌面端 channel
#[derive(Debug, Clone, Deserialize)]
pub struct ChannelRoute {
    /// 指令前缀(如 "/dev2 xxx" 路由到 chan-home);空串=默认 channel
    pub prefix: String,
    /// u-relay channel_id(桌面端 df-tunnel 配置的同一 channel)
    pub channel_id: String,
}

/// 飞书企业自建应用凭证
#[derive(Debug, Clone, Deserialize)]
pub struct FeishuConfig {
    pub app_id: String,
    pub app_secret: String,
    /// 长连接模式事件订阅(免公网回调;当前恒 true,保留显式开关供回调模式扩展)
    #[allow(dead_code)]
    pub long_connection: bool,
}

fn default_throttle_ms() -> u64 {
    800
}

impl GatewayConfig {
    /// 从 env + 可选 toml 文件构建。缺失关键项(relay_url/token)返回 Err。
    pub fn load() -> anyhow::Result<Self> {
        let relay_url = std::env::var("GATEWAY_RELAY_URL")
            .unwrap_or_else(|_| "ws://127.0.0.1:9180/ws/commander".to_string());
        let relay_token = std::env::var("GATEWAY_RELAY_TOKEN")
            .or_else(|_| std::env::var("U_RELAY_TOKEN"))
            .map_err(|_| anyhow::anyhow!("缺少 GATEWAY_RELAY_TOKEN / U_RELAY_TOKEN 环境变量"))?;

        let feishu = match (
            std::env::var("FEISHU_APP_ID"),
            std::env::var("FEISHU_APP_SECRET"),
        ) {
            (Ok(app_id), Ok(app_secret)) => Some(FeishuConfig {
                app_id,
                app_secret,
                long_connection: true,
            }),
            _ => None,
        };

        let whitelist = std::env::var("GATEWAY_WHITELIST")
            .map(|v| v.split(',').map(|s| s.trim().to_string()).filter(|s| !s.is_empty()).collect())
            .unwrap_or_default();

        let default_channel = std::env::var("GATEWAY_DEFAULT_CHANNEL").unwrap_or_default();
        let channels = if default_channel.is_empty() {
            Vec::new()
        } else {
            vec![ChannelRoute { prefix: String::new(), channel_id: default_channel }]
        };

        Ok(Self {
            relay_url,
            relay_token,
            channels,
            feishu,
            throttle_ms: default_throttle_ms(),
            whitelist,
        })
    }

    /// 查指令应路由到的 channel(前缀匹配,空前缀=兜底默认)
    pub fn route(&self, command_text: &str) -> Option<&str> {
        // 精确前缀优先,空前缀兜底
        self.channels
            .iter()
            .find(|c| !c.prefix.is_empty() && command_text.starts_with(&c.prefix))
            .map(|c| c.channel_id.as_str())
            .or_else(|| self.channels.iter().find(|c| c.prefix.is_empty()).map(|c| c.channel_id.as_str()))
    }
}

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

    #[test]
    fn route_prefix_priority() {
        let cfg = GatewayConfig {
            relay_url: String::new(),
            relay_token: String::new(),
            channels: vec![
                ChannelRoute { prefix: "/dev2".into(), channel_id: "chan-home".into() },
                ChannelRoute { prefix: String::new(), channel_id: "chan-work".into() },
            ],
            feishu: None,
            throttle_ms: 800,
            whitelist: vec![],
        };
        assert_eq!(cfg.route("/dev2 修个 bug"), Some("chan-home"));
        assert_eq!(cfg.route("普通指令"), Some("chan-work"));
        assert_eq!(cfg.route("/dev2"), Some("chan-home"));
    }

    #[test]
    fn route_empty_when_no_channels() {
        let cfg = GatewayConfig {
            relay_url: String::new(),
            relay_token: String::new(),
            channels: vec![],
            feishu: None,
            throttle_ms: 800,
            whitelist: vec![],
        };
        assert_eq!(cfg.route("任何"), None);
    }
}