use std::env::current_exe;
use std::fs;
use std::path::Path;
use tracing::{error, Level, subscriber};
use tracing_appender::non_blocking::{WorkerGuard};
use tracing_appender::rolling::{RollingFileAppender, Rotation};
use tracing_unwrap::{OptionExt, ResultExt};
use crate::constants::{FAILOVER_LOG_LEVEL_KEY, GATEWAY_LOG_LEVEL_KEY, NODE_LOG_LEVEL_KEY, TICKET_LOG_LEVEL_KEY};
use crate::parameter_store::get_parameter;

fn read_cargo_toml() -> toml::Value{
    let cargo_toml_content = fs::read_to_string("Cargo.toml")
        .expect_or_log("Failed to read Cargo.toml file");

    let cargo_toml: toml::Value = toml::from_str(&cargo_toml_content)
        .expect_or_log("Failed to parse Cargo.toml");

    cargo_toml
}

fn get_app_name() -> Option<String> {
    let cargo_toml = read_cargo_toml();

    let package = cargo_toml
        .get("package")
        .expect("`[package]` section is missing in Cargo.toml");

    let name = package
        .get("name")
        .expect_or_log("`name` field is missing in Cargo.toml");

    let name_str = name
        .as_str()
        .expect_or_log("Package name is not a string");

    Option::from(name_str.to_string())
}

fn get_log_level_parameter_key() -> Option<String> {
    let mut ret: Option<String> = None;

    match get_app_name() {
        None => { ret = None }
        Some(app_name) => {
            match app_name.as_str() {
                "device-gateway" => { ret = Option::from(GATEWAY_LOG_LEVEL_KEY.to_string()) }
                "device-node" => { ret = Option::from(NODE_LOG_LEVEL_KEY.to_string()) }
                "device-ticket" => { ret = Option::from(TICKET_LOG_LEVEL_KEY.to_string()) }
                "device-failover" => { ret = Option::from(FAILOVER_LOG_LEVEL_KEY.to_string()) }
                _ => { return ret }
            }
        }
    }

    ret
}

pub async fn init(log_file_name: &str) -> WorkerGuard {
    let mut level: Level = Level::INFO;

    let log_level_parameter_key = get_log_level_parameter_key()
        .expect("log level parameter key not found");

    let log_level = get_parameter(log_level_parameter_key).await;

    match log_level.to_lowercase().as_str() {
        "debug" => { level = Level::DEBUG },
        "info" => { level = Level::INFO },
        "warn" => { level = Level::WARN },
        _ => {}
    }

    let log_dir = get_log_dir();
    if !Path::new(&log_dir).exists() {
        fs::create_dir_all(&log_dir).expect("failed to create log directory");
    }

    let file_appender = RollingFileAppender::builder()
        .rotation(Rotation::DAILY)
        .filename_suffix(log_file_name)
        .build(log_dir)
        .expect("failed to initialize rolling file appender");

    let (file_writer, _guard) = tracing_appender::non_blocking(file_appender);

    let subscriber = tracing_subscriber::fmt()
        .with_max_level(level)
        .with_writer(file_writer)
        //.with_writer(console_writer)
        .with_ansi(false)
        .finish();

    subscriber::set_global_default(subscriber)
        .expect("trace init fail");

    _guard
}

pub fn expect_or_log<T>(result: Result<T, impl ToString>, message: &str) -> T {
    match result {
        Ok(val) => val,
        Err(err) => {
            let err_message = err.to_string();
            error!("{}: {}", message, err_message);
            panic!("{}: {}", message, err_message);
        }
    }
}

fn get_log_dir() -> String {
    let mut current_dir = current_exe().unwrap();
    current_dir.pop();
    current_dir.push("log");
    current_dir.display().to_string()
}