/// High level API for the SSV library,
/// based on the low level bindings in libssv.rs.
extern crate dotenv;
use libc::{c_void, size_t};
use std::env;
use std::ffi::CString;
use std::path::PathBuf;
use std::ptr;
use thiserror::Error;

use crate::cps::lire_carte;
use crate::libssv::{SSV_InitLIB2, SSV_LireConfig};

#[derive(Error, Debug)]
pub enum SSVDemoError {
    #[error(transparent)]
    CartePSReading(#[from] crate::cps::CartePSError),
    #[error(transparent)]
    SSVLibErrorCode(#[from] crate::libssv::LibSSVError),
}

fn ssv_init_lib_2() -> Result<(), SSVDemoError> {
    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);
        if result != 0 {
            return Err(crate::libssv::LibSSVError::StandardErrorCode {
                code: result,
                function: "SSV_InitLIB2",
            }
            .into());
        }
    }
    Ok(())
}

fn ssv_lire_config() -> Result<(), SSVDemoError> {
    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 result != 0 {
            return Err(crate::libssv::LibSSVError::StandardErrorCode {
                code: result,
                function: "SSV_LireConfig",
            }
            .into());
        }

        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);
        }
    }
    Ok(())
}

pub fn demo() -> Result<(), SSVDemoError> {
    // 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").expect("CARGO_MANIFEST_DIR must be set");
    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()?;

    let code_pin = "1234";
    let lecteur = "HID Global OMNIKEY 3x21 Smart Card Reader 0";
    let carte_ps = lire_carte(code_pin, lecteur)?;
    println!("CartePS: {:#?}", carte_ps);

    ssv_lire_config()?;

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