#![allow(non_upper_case_globals)]
#![allow(non_camel_case_types)]
#![allow(non_snake_case)]

#[derive(Debug)]
pub enum SUPPORTED_FSV_VERSIONS {
    V1_40_14, // 1.40.14
    V1_40_13, // 1.40.13
}

impl SUPPORTED_FSV_VERSIONS {
    fn as_str(&self) -> &'static str {
        match self {
            Self::V1_40_14 => "1.40.14",
            Self::V1_40_13 => "1.40.13",
        }
    }
}

pub mod BINDINGS {
    include!(concat!(env!("OUT_DIR"), "/bindings_1.40.13.rs"));
}

// We need to keep the this use statement to get `ssv_function` macro working well
use BINDINGS::*;

/// Macro to generate a function that implements a call to an external function in BINDINGS
macro_rules! ssv_function {
    ($binding:ty, $func_name:ident, {$($arg_name:ident: $arg_type:ty),*}) => {
        /// # Safety
        /// This function is unsafe because it calls an external function through FFI.
        /// The caller must ensure that the provided arguments are valid and that the
        /// external function is safe to call.
        pub unsafe fn $func_name(&self, $($arg_name: $arg_type),*) -> Result<u16, Error> {
            let func_struct: libloading::Symbol<'_, $binding> =
                unsafe { self.library.get(stringify!($binding).as_bytes())? };
            let func = match *func_struct {
                Some(func) => func,
                None => return Err(Error::SymbolMissing(stringify!($binding))),
            };
            Ok(func($($arg_name),*))
        }
    };
}

#[derive(thiserror::Error, Debug)]
pub enum Error {
    #[error(transparent)]
    LibLoading(#[from] libloading::Error),
    #[error("Symbol missing: {0}")]
    SymbolMissing(&'static str),
}

/// Wrapper around the SESAM-VITALE library
/// This struct is responsible for loading the library and providing an interface to call its functions.
/// The library is loaded at creation and kept in memory until the struct is dropped.
#[derive(Debug)]
pub struct SSVLibrary {
    version: SUPPORTED_FSV_VERSIONS,
    library: libloading::Library,
}

fn get_library_name() -> &'static str {
    // TODO : Use libloading::library_filename to get platform-specific filename ?
    "libssvlux64.so"
}

fn get_library_root_path() -> &'static str {
    "/opt/santesocial/fsv"
}

fn get_sesam_ini_root_path() -> &'static str {
    "/etc/opt/santesocial/fsv"
}

impl SSVLibrary {
    pub fn new(version: SUPPORTED_FSV_VERSIONS) -> Result<Self, Error> {
        let library_path = Self::get_library_path(&version);
        let library = unsafe { libloading::Library::new(library_path)? };
        Ok(SSVLibrary { version, library })
    }

    pub fn library(&self) -> &libloading::Library {
        &self.library
    }

    pub fn sesam_ini_path(&self) -> String {
        let root_path = get_sesam_ini_root_path();
        let version = self.version.as_str();
        format!("{root_path}/{version}/conf/sesam.ini")
    }

    pub fn get_library_path(version: &SUPPORTED_FSV_VERSIONS) -> String {
        let root_path = get_library_root_path();
        let library_name = get_library_name();
        let version = version.as_str();
        format!("{root_path}/{version}/lib/{library_name}")
    }

    ssv_function!(SSV_InitLIB2, ssv_init_lib2, {
        pcFichierSesam: *const i8
    });

    ssv_function!(SSV_LireConfig, ssv_lire_config, {
        pZDataOut: *mut *mut libc::c_void,
        psTailleDataOut: *mut usize
    });

    ssv_function!(SSV_LireCartePS, ssv_lire_carte_ps, {
        NomRessourcePS: *const i8,
        NomRessourceLecteur: *const i8,
        CodePorteurPS: *const i8,
        pZDataOut: *mut *mut libc::c_void,
        pTailleZone: *mut usize
    });
}

#[cfg(test)]
mod test {
    use std::{ffi::CString, ptr};

    use super::*;

    #[test]
    fn test_initlib2() {
        let ssv_library =
            SSVLibrary::new(SUPPORTED_FSV_VERSIONS::V1_40_13).expect("SSVLibrary::new failed");

        let sesam_ini_str =
            CString::new(ssv_library.sesam_ini_path()).expect("CString::new failed");
        let result = unsafe { ssv_library.ssv_init_lib2(sesam_ini_str.as_ptr()) }.unwrap();
        assert_eq!(result, 0);
    }

    #[test]
    fn test_lire_config_and_carte_ps() {
        let ssv_library =
            SSVLibrary::new(SUPPORTED_FSV_VERSIONS::V1_40_13).expect("SSVLibrary::new failed");

        let sesam_ini_str =
            CString::new(ssv_library.sesam_ini_path()).expect("CString::new failed");
        let result = unsafe { ssv_library.ssv_init_lib2(sesam_ini_str.as_ptr()) }.unwrap();
        assert_eq!(result, 0);

        let mut buffer_ptr: *mut libc::c_void = ptr::null_mut();
        let mut size: libc::size_t = 0;
        let result = unsafe { ssv_library.ssv_lire_config(&mut buffer_ptr, &mut size) }.unwrap();
        assert_eq!(result, 0);

        let nom_ressource_ps =
            CString::new("Gemalto PC Twin Reader (645D94C3) 00 00").expect("CString::new failed");
        let nom_ressource_lecteur =
            CString::new("Gemalto PC Twin Reader (645D94C3) 00 00").expect("CString::new failed");
        let code_porteur_ps = CString::new("1234").expect("CString::new failed");
        let mut buffer_ptr: *mut libc::c_void = ptr::null_mut();
        let mut size: libc::size_t = 0;
        let result = unsafe {
            ssv_library.ssv_lire_carte_ps(
                nom_ressource_ps.as_ptr(),
                nom_ressource_lecteur.as_ptr(),
                code_porteur_ps.as_ptr(),
                &mut buffer_ptr,
                &mut size,
            )
        }
        .unwrap();
        assert_eq!(result, 0);
    }
}