use thiserror::Error;
use std::{ffi::CString, fmt, path::Path, ptr};

use crate::{bindings::{SSV_InitLIB2, SSV_TermLIB}, types::{common::read_from_buffer, configuration::Configuration}};

#[derive(Error, Debug)]
pub struct SesamVitaleError {
    code: u16,
}

impl fmt::Display for SesamVitaleError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "Got error code {} from SSV_LireConfig", self.code)
    }
}

pub fn init_library(sesam_ini_path: &Path) -> Result<(), SesamVitaleError> {
    // TODO: better error handling
    let path_str = sesam_ini_path.to_str().unwrap();
    let path_ptr = CString::new(path_str).expect("failed to create cstring");

    let exit_code: u16 = unsafe { SSV_InitLIB2(path_ptr.as_ptr()) };
    if exit_code != 0 {
        let error = SesamVitaleError { code: exit_code };
        return Err(error);
    };

    Ok(())
}
pub fn close_library() -> Result<(), SesamVitaleError> {
    let exit_code: u16 = unsafe { SSV_TermLIB() };
    if exit_code != 0 {
        let error = SesamVitaleError { code: exit_code };
        return Err(error);
    };

    Ok(())
}

pub fn read_config() -> Result<Configuration, SesamVitaleError> {
    let mut buffer_ptr: *mut libc::c_void = ptr::null_mut();
    let mut size: libc::size_t = 0;

    let buffer_ptr_ptr: *mut *mut libc::c_void = &mut buffer_ptr;
    let size_ptr: *mut libc::size_t = &mut size;

    // Need to add proper error handling -> return a result with error code pointing to an error
    // enum
    let exit_code: u16 = unsafe { SSV_LireConfig(buffer_ptr_ptr, size_ptr) };

    if exit_code != 0 {
        let error = SesamVitaleError { code: exit_code };
        return Err(error);
    };

    let buffer: &[u8] = unsafe { std::slice::from_raw_parts(buffer_ptr as *const u8, size) };

    // TODO: Improve error handling
    let configuration: Configuration = read_from_buffer(buffer).unwrap();

    // TODO: Call library function for memory delocating
    unsafe { libc::free(buffer_ptr) };

    Ok(configuration)
}