use ffi;
use ssl::error::SslError;
use bn::BigNum;
use std::mem;
use std::ptr;

pub struct DH(*mut ffi::DH);

impl DH {
    pub fn from_params(p: BigNum, g: BigNum, q: BigNum) -> Result<DH, SslError> {
        let dh = unsafe { ffi::DH_new_from_params(p.raw(), g.raw(), q.raw()) };
        if dh == ptr::null_mut() {
            return Err(SslError::get());
        }
        mem::forget(p);
        mem::forget(g);
        mem::forget(q);
        Ok(DH(dh))
    }

    #[cfg(feature = "rfc5114")]
    pub fn get_1024_160() -> Result<DH, SslError> {
        let dh = unsafe { ffi::DH_get_1024_160() };
        if dh == ptr::null_mut() {
            return Err(SslError::get());
        }
        Ok(DH(dh))
    }

    #[cfg(feature = "rfc5114")]
    pub fn get_2048_224() -> Result<DH, SslError> {
        let dh = unsafe { ffi::DH_get_2048_224() };
        if dh == ptr::null_mut() {
            return Err(SslError::get());
        }
        Ok(DH(dh))
    }

    #[cfg(feature = "rfc5114")]
    pub fn get_2048_256() -> Result<DH, SslError> {
        let dh = unsafe { ffi::DH_get_2048_256() };
        if dh == ptr::null_mut() {
            return Err(SslError::get());
        }
        Ok(DH(dh))
    }

    pub unsafe fn raw(&self) -> *mut ffi::DH {
        let DH(n) = *self;
        n
    }

    pub unsafe fn raw_ptr(&self) -> *const *mut ffi::DH {
        let DH(ref n) = *self;
        n
    }
}

impl Drop for DH {
    fn drop(&mut self) {
        unsafe {
            if !self.raw().is_null() {
                ffi::DH_free(self.raw())
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::DH;
    use bn::BigNum;
    use ssl::SslContext;
    use ssl::SslMethod::Sslv23;

    #[test]
    #[cfg(feature = "rfc5114")]
    fn test_dh_rfc5114() {
        let ctx = SslContext::new(Sslv23).unwrap();
        let dh1 = DH::get_1024_160().unwrap();
        ctx.set_tmp_dh(dh1).unwrap();
        let dh2 = DH::get_2048_224().unwrap();
        ctx.set_tmp_dh(dh2).unwrap();
        let dh3 = DH::get_2048_256().unwrap();
        ctx.set_tmp_dh(dh3).unwrap();
    }

    #[test]
    fn test_dh() {
        let ctx = SslContext::new(Sslv23).unwrap();
        let p = BigNum::from_hex_str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unwrap();
        let g = BigNum::from_hex_str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unwrap();
        let q = BigNum::from_hex_str("8CF83642A709A097B447997640129DA299B1A47D1EB3750BA308B0FE64F5FBD3").unwrap();
        let dh = DH::from_params(p, g, q).unwrap();
        ctx.set_tmp_dh(dh).unwrap();
    }
}