use axum::{
    extract::State,
    http::StatusCode,
    response::Html,
    routing::{get, post},
    Json, Router,
};
use reqwest::Client;
use serde::{Deserialize, Serialize};
use std::env;
use tower_http::services::ServeDir;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};

#[derive(Debug, Deserialize)]
struct ChatRequest {
    model: String,
    messages: Vec<ChatMessage>,
}

#[derive(Debug, Serialize, Deserialize, Clone)]
struct ChatMessage {
    role: String,
    content: String,
}

#[derive(Debug, Serialize)]
struct ChatResponse {
    reply: String,
}

#[derive(Clone)]
struct AppState {
    client: Client,
    api_key: String,
    base_url: String,
}

#[tokio::main]
async fn main() {
    tracing_subscriber::registry()
        .with(tracing_subscriber::EnvFilter::new("info"))
        .with(tracing_subscriber::fmt::layer())
        .init();

    let api_key = env::var("PUTER_API_KEY").expect("❌ PUTER_API_KEY not set");
    let base_url = env::var("PUTER_BASE_URL")
        .unwrap_or_else(|_| "https://api.puter.com/puterai/openai/v1/".to_string());
    let port = env::var("PORT").unwrap_or_else(|_| "7860".to_string());

    let state = AppState {
        client: Client::new(),
        api_key,
        base_url,
    };

    // Раздаём статические файлы из папки static/
    let app = Router::new()
        .nest_service("/", ServeDir::new("static"))
        .route("/api/chat", post(handle_chat))
        .with_state(state);

    let addr = format!("0.0.0.0:{}", port);
    tracing::info!("🚀 Server running on http://{}", addr);
    let listener = tokio::net::TcpListener::bind(&addr).await.unwrap();
    axum::serve(listener, app).await.unwrap();
}

async fn handle_chat(
    State(state): State<AppState>,
    Json(req): Json<ChatRequest>,
) -> Result<Json<ChatResponse>, (StatusCode, String)> {
    let mut messages = vec![ChatMessage {
        role: "system".into(),
        content: "Ты полезный ассистент. Отвечай кратко и по делу.".into(),
    }];
    messages.extend(req.messages);

    let payload = serde_json::json!({
        "model": req.model,
        "messages": messages,
        "temperature": 0.7,
        "max_tokens": 2048
    });

    let res = state
        .client
        .post(&format!("{}chat/completions", state.base_url))
        .header("Authorization", format!("Bearer {}", state.api_key))
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await
        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("Network error: {}", e)))?;

    if !res.status().is_success() {
        let err_text = res.text().await.unwrap_or_default();
        tracing::error!("Puter API error: {}", err_text);
        return Err((StatusCode::BAD_GATEWAY, format!("API error: {}", err_text)));
    }

    let json: serde_json::Value = res.json().await.map_err(|e| {
        (StatusCode::INTERNAL_SERVER_ERROR, format!("JSON parse error: {}", e))
    })?;

    let reply = json["choices"][0]["message"]["content"]
        .as_str()
        .unwrap_or("❌ Пустой ответ от API")
        .to_string();

    Ok(Json(ChatResponse { reply }))
}