/**
 * High level API for the SSV library,
 * based on the low level bindings in libssv.rs.
 * 
 */

extern crate libc;
extern crate dotenv;

use libc::{ c_void, size_t };
use std::ffi::CString;
use std::path::PathBuf;
use std::ptr;

use std::env;

use crate::libssv:: {
    SSV_InitLIB2,
    SSV_LireCartePS,
    SSV_LireConfig
};

fn ssv_init_lib_2() {
    let ini_str = env::var("SESAM_INI_PATH").expect("SESAM_INI_PATH must be set");
    let ini = CString::new(ini_str).expect("CString::new failed");
    unsafe {
        let result = SSV_InitLIB2(ini.as_ptr());
        println!("SSV_InitLIB2 result: {}", result);
    }
}

fn ssv_lire_carte_ps() {
    let resource_ps = CString::new("PS").expect("CString::new failed");
    let resource_reader = CString::new("TRANSPA1").expect("CString::new failed");
    let card_number = CString::new("1234567890").expect("CString::new failed");

    let mut buffer: *mut c_void = ptr::null_mut();
    let mut size: size_t = 0;
    unsafe {
        let result = SSV_LireCartePS(
            resource_ps.as_ptr(),
            resource_reader.as_ptr(),
            card_number.as_ptr(),
            &mut buffer,
            &mut size
        );
        println!("SSV_LireCartePS result: {}", result);

        if !buffer.is_null() {
            let hex_values = std::slice::from_raw_parts(buffer as *const u8, size);
            for &byte in hex_values {
                print!("{:02X} ", byte);
            }
            println!();

            libc::free(buffer);
        }
    }
}

fn ssv_lire_config() {
    let mut buffer: *mut c_void = ptr::null_mut();
    let mut size: size_t = 0;
    unsafe {
        let result = SSV_LireConfig(&mut buffer, &mut size);
        println!("SSV_LireConfig result: {}", result);

        if !buffer.is_null() {
            let hex_values = std::slice::from_raw_parts(buffer as *const u8, size);
            for &byte in hex_values {
                print!("{:02X} ", byte);
            }
            println!();

            libc::free(buffer);
        }
    }
}

pub fn demo() {
    /*
     * TODO : this is probably not working on release, because I'm not sure it exists a CARGO_MANIFEST_DIR and so it can find the `.env`
     * Maybe we could use a system standard config path to store a config file
     */ 
    let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
    let manifest_path = PathBuf::from(manifest_dir);
    dotenv::from_path(manifest_path.join(".env")).ok();

    println!("------- Demo for the SSV library --------");

    ssv_init_lib_2();
    ssv_lire_carte_ps();
    ssv_lire_config();

    println!("-----------------------------------------");
}