use serde::{Deserialize, Serialize};
use std::fs;
use std::path::PathBuf;

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct AppSettings {
    #[serde(default = "default_base_url")]
    pub base_url: String,
    /// 自定义形象图片 URL（通过 /api/media/upload 上传后本地记录）
    #[serde(default)]
    pub custom_mascot_url: Option<String>,
}

impl Default for AppSettings {
    fn default() -> Self {
        Self { base_url: default_base_url(), custom_mascot_url: None }
    }
}

fn default_base_url() -> String {
    "https://cfc.cf-club.com".to_string()
}

pub struct SettingsStore {
    path: PathBuf,
}

impl SettingsStore {
    pub fn new(app_config_dir: PathBuf) -> Self {
        Self { path: app_config_dir.join("settings.json") }
    }

    pub fn load(&self) -> AppSettings {
        match fs::read_to_string(&self.path) {
            Ok(txt) => serde_json::from_str(&txt).unwrap_or_default(),
            Err(_) => AppSettings::default(),
        }
    }

    pub fn save(&self, s: &AppSettings) -> Result<(), String> {
        if let Some(dir) = self.path.parent() {
            fs::create_dir_all(dir).map_err(|e| e.to_string())?;
        }
        let txt = serde_json::to_string_pretty(s).map_err(|e| e.to_string())?;
        fs::write(&self.path, txt).map_err(|e| e.to_string())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;
    use std::sync::atomic::{AtomicUsize, Ordering};

    static COUNTER: AtomicUsize = AtomicUsize::new(0);

    fn temp_dir() -> std::path::PathBuf {
        let n = COUNTER.fetch_add(1, Ordering::SeqCst);
        let dir = std::env::temp_dir().join(format!("xafpet-settings-test-{}", n));
        let _ = fs::remove_dir_all(&dir);
        dir
    }

    #[test]
    fn default_when_file_missing() {
        let store = SettingsStore::new(temp_dir());
        let cfg = store.load();
        assert_eq!(cfg.base_url, "https://cfc.cf-club.com");
    }

    #[test]
    fn default_when_file_malformed() {
        let dir = temp_dir();
        fs::create_dir_all(&dir).unwrap();
        fs::write(dir.join("settings.json"), "not json").unwrap();
        let store = SettingsStore::new(dir);
        let cfg = store.load();
        assert_eq!(cfg.base_url, "https://cfc.cf-club.com");
    }

    #[test]
    fn roundtrip_save_load() {
        let dir = temp_dir();
        let store = SettingsStore::new(dir.clone());
        let mut cfg = store.load();
        cfg.base_url = "http://192.168.1.5:9082".into();
        store.save(&cfg).unwrap();

        let store2 = SettingsStore::new(dir.clone());
        assert_eq!(store2.load().base_url, "http://192.168.1.5:9082");
        let _ = fs::remove_dir_all(&dir);
    }

    #[test]
    fn custom_mascot_url_roundtrip() {
        let dir = temp_dir();
        let store = SettingsStore::new(dir.clone());
        let mut cfg = store.load();
        assert!(cfg.custom_mascot_url.is_none());
        cfg.custom_mascot_url = Some("https://cdn.example/x.png".into());
        store.save(&cfg).unwrap();

        let loaded = SettingsStore::new(dir.clone()).load();
        assert_eq!(loaded.custom_mascot_url.as_deref(), Some("https://cdn.example/x.png"));
        let _ = fs::remove_dir_all(&dir);
    }
}