use directories::ProjectDirs;
use figment::{
    Figment,
    providers::{Env, Format, Serialized, Toml},
};
use serde::{Deserialize, Serialize};
use std::path::PathBuf;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Settings {
    #[serde(default = "default_ollama_url")]
    pub ollama_url: String,
    #[serde(default = "default_model")]
    pub model: String,
    #[serde(default = "default_mode")]
    pub mode: String, // "plan" (read-only) for now
}

fn default_ollama_url() -> String {
    "http://localhost:11434".into()
}
fn default_model() -> String {
    "qwen3:8b".into()
}
fn default_mode() -> String {
    "plan".into()
}

impl Default for Settings {
    fn default() -> Self {
        Self {
            ollama_url: default_ollama_url(),
            model: default_model(),
            mode: default_mode(),
        }
    }
}

pub fn load_settings(project_root: Option<&str>) -> Result<Settings, figment::Error> {
    let mut fig = Figment::from(Serialized::defaults(Settings::default()));

    // User file: ~/.config/owlen/config.toml
    if let Some(pd) = ProjectDirs::from("dev", "owlibou", "owlen") {
        let user = pd.config_dir().join("config.toml");
        fig = fig.merge(Toml::file(user));
    }

    // Project file: <root>/.owlen.toml
    if let Some(root) = project_root {
        fig = fig.merge(Toml::file(PathBuf::from(root).join(".owlen.toml")));
    }

    // Environment variables have highest precedence
    fig = fig.merge(Env::prefixed("OWLEN_").split("__"));

    fig.extract()
}