// src/services/logging.rs
use chrono::{DateTime, FixedOffset, Utc};
use std::env;
use std::fs;
use tracing_appender::non_blocking::WorkerGuard;
use tracing_appender::rolling;
use tracing_subscriber::fmt::format::Writer;
use tracing_subscriber::fmt::time::FormatTime;
use tracing_subscriber::{
    fmt, layer::SubscriberExt, util::SubscriberInitExt,
    EnvFilter, Layer,
};

pub struct ShanghaiTime;

impl FormatTime for ShanghaiTime {
    fn format_time(&self, w: &mut Writer<'_>) -> std::fmt::Result {
        let now: DateTime<Utc> = Utc::now();
        let offset = FixedOffset::east_opt(8 * 3600).unwrap();
        let shanghai_time = now.with_timezone(&offset);
        write!(w, "{}", shanghai_time.format("%Y-%m-%dT%H:%M:%S%.3f%:z"))
    }
}

/// 初始化系统全局日志模块，支持控制台输出与每天自动滚动的日志文件
pub fn init_logging() -> anyhow::Result<Vec<WorkerGuard>> {
    let mut guards = Vec::new();

    // 从环境变量中读取配置
    let log_level = env::var("LOG_LEVEL").unwrap_or_else(|_| "info,astroresearch=debug".to_string());
    let log_format = env::var("LOG_FORMAT").unwrap_or_else(|_| "pretty".to_string());
    let log_outputs = env::var("LOG_OUTPUTS").unwrap_or_else(|_| "stdout,file".to_string());

    let env_filter = EnvFilter::try_from_default_env()
        .unwrap_or_else(|_| EnvFilter::new(&log_level));
    let is_json = log_format.to_lowercase() == "json";

    let mut layers: Vec<Box<dyn Layer<tracing_subscriber::Registry> + Send + Sync>> = Vec::new();

    // 1. 控制台输出层 (stdout)
    if log_outputs.contains("stdout") {
        let (non_blocking, guard) = tracing_appender::non_blocking(std::io::stdout());
        guards.push(guard);

        let fmt_layer = fmt::layer()
            .with_timer(ShanghaiTime)
            .with_writer(non_blocking);

        if is_json {
            layers.push(fmt_layer.json().with_ansi(false).boxed());
        } else {
            layers.push(fmt_layer.pretty().with_ansi(true).boxed());
        }
    }

    // 2. 每日滚动文件日志层 (file)
    if log_outputs.contains("file") {
        let log_dir = env::var("LOG_DIR").unwrap_or_else(|_| "logs".to_string());
        fs::create_dir_all(&log_dir).unwrap_or(());

        let file_appender = rolling::daily(log_dir, "astro_research.log");
        let (non_blocking, guard) = tracing_appender::non_blocking(file_appender);
        guards.push(guard);

        let fmt_layer = fmt::layer()
            .with_timer(ShanghaiTime)
            .with_writer(non_blocking)
            .with_ansi(false);

        if is_json {
            layers.push(fmt_layer.json().boxed());
        } else {
            layers.push(fmt_layer.boxed());
        }
    }

    // 3. 注册全部日志层
    tracing_subscriber::registry()
        .with(layers)
        .with(env_filter)
        .init();

    Ok(guards)
}