use crate::log::*;
use std::fs;

pub fn set_timezone(timezone: Option<String>) -> Result<(), Box<dyn std::error::Error>> {
    let tz = match timezone {
        Some(tz) => tz,
        None => {
            if let Ok(content) = fs::read_to_string("/etc/timezone") {
                content.trim().to_string()
            } else if let Ok(link_info) = fs::read_link("/etc/localtime") {
                let path_str = link_info.to_string_lossy();
                if path_str.starts_with("/usr/share/zoneinfo/") {
                    let tz_part = path_str.strip_prefix("/usr/share/zoneinfo/").unwrap_or("");
                    tz_part.to_string()
                } else {
                    "UTC".to_string()
                }
            } else {
                "UTC".to_string()
            }
        }
    };

    let tz_file_path = format!("/usr/share/zoneinfo/{}", tz);

    if !std::path::Path::new(&tz_file_path).exists() {
        log_warning(&format!(
            "Timezone '{}' not found in zoneinfo, using UTC",
            tz
        ));
        let result = set_system_timezone_to_utc();
        if let Err(e) = result {
            log_critical_error(&format!("Failed to set timezone to UTC: {}", e));
            return Err(e);
        }
        return Ok(());
    }

    if std::path::Path::new("/etc/localtime").exists() {
        std::fs::remove_file("/etc/localtime")?;
    }

    std::os::unix::fs::symlink(&tz_file_path, "/etc/localtime")?;

    log_success(&format!("Timezone set to {}", tz));

    unsafe {
        std::env::set_var("TZ", &tz);
    }

    Ok(())
}

fn set_system_timezone_to_utc() -> Result<(), Box<dyn std::error::Error>> {
    let utc_tz_path = "/usr/share/zoneinfo/Etc/UTC";
    if std::path::Path::new("/etc/localtime").exists() {
        std::fs::remove_file("/etc/localtime")?;
    }

    std::os::unix::fs::symlink(utc_tz_path, "/etc/localtime")?;
    log_success("Timezone set to UTC");
    unsafe {
        std::env::set_var("TZ", "UTC");
    }

    Ok(())
}