#[cfg(feature = "bindgen")]
use bindgen::callbacks::{MacroParsingBehavior, ParseCallbacks};
#[cfg(feature = "bindgen")]
use bindgen::{MacroTypeVariation, RustTarget};
use std::io::Write;
use std::path::PathBuf;
#[cfg(not(feature = "bindgen"))]
use std::process;
use std::{env, fs};

const INCLUDES: &str = "
#include <openssl/aes.h>
#include <openssl/asn1.h>
#include <openssl/bio.h>
#include <openssl/cmac.h>
#include <openssl/conf.h>
#include <openssl/crypto.h>
#include <openssl/dh.h>
#include <openssl/dsa.h>
#include <openssl/ec.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/objects.h>
#include <openssl/opensslv.h>
#include <openssl/pem.h>
#include <openssl/pkcs12.h>
#include <openssl/pkcs7.h>
#include <openssl/rand.h>
#include <openssl/rsa.h>
#include <openssl/safestack.h>
#include <openssl/sha.h>
#include <openssl/ssl.h>
#include <openssl/stack.h>
#include <openssl/x509.h>
#include <openssl/x509_vfy.h>
#include <openssl/x509v3.h>

// this must be included after ssl.h for libressl!
#include <openssl/srtp.h>

#if !defined(LIBRESSL_VERSION_NUMBER) && !defined(OPENSSL_IS_BORINGSSL)
#include <openssl/cms.h>
#endif

#if !defined(OPENSSL_IS_BORINGSSL)
#include <openssl/comp.h>
#include <openssl/ocsp.h>
#endif

#if !defined(LIBRESSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER >= 0x10100000
#include <openssl/kdf.h>
#endif

#if OPENSSL_VERSION_NUMBER >= 0x30000000
#include <openssl/provider.h>
#endif

#if defined(LIBRESSL_VERSION_NUMBER) || defined(OPENSSL_IS_BORINGSSL)
#include <openssl/poly1305.h>
#endif
";

#[cfg(feature = "bindgen")]
pub fn run(include_dirs: &[PathBuf]) {
    let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());

    let mut builder = bindgen::builder()
        .parse_callbacks(Box::new(OpensslCallbacks))
        .rust_target(RustTarget::Stable_1_47)
        .ctypes_prefix("::libc")
        .raw_line("use libc::*;")
        .raw_line("type evp_pkey_st = EVP_PKEY;")
        .allowlist_file(".*/openssl/[^/]+\\.h")
        .allowlist_recursively(false)
        // libc is missing pthread_once_t on macOS
        .blocklist_type("CRYPTO_ONCE")
        .blocklist_function("CRYPTO_THREAD_run_once")
        // we don't want to mess with va_list
        .blocklist_function("BIO_vprintf")
        .blocklist_function("BIO_vsnprintf")
        .blocklist_function("ERR_vset_error")
        .blocklist_function("ERR_add_error_vdata")
        .blocklist_function("EVP_KDF_vctrl")
        .blocklist_type("OSSL_FUNC_core_vset_error_fn")
        .blocklist_type("OSSL_FUNC_BIO_vprintf_fn")
        .blocklist_type("OSSL_FUNC_BIO_vsnprintf_fn")
        // Maintain compatibility for existing enum definitions
        .rustified_enum("point_conversion_form_t")
        // Maintain compatibility for pre-union definitions
        .blocklist_type("GENERAL_NAME")
        .blocklist_type("GENERAL_NAME_st")
        .blocklist_type("EVP_PKEY")
        .blocklist_type("evp_pkey_st")
        .layout_tests(false)
        .header_contents("includes.h", INCLUDES);

    for include_dir in include_dirs {
        builder = builder
            .clang_arg("-I")
            .clang_arg(include_dir.display().to_string());
    }

    builder
        .generate()
        .unwrap()
        .write_to_file(out_dir.join("bindgen.rs"))
        .unwrap();
}

#[cfg(feature = "bindgen")]
pub fn run_boringssl(include_dirs: &[PathBuf]) {
    let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
    let mut builder = bindgen::builder()
        .rust_target(RustTarget::Stable_1_47)
        .ctypes_prefix("::libc")
        .raw_line("use libc::*;")
        .derive_default(false)
        .enable_function_attribute_detection()
        .default_macro_constant_type(MacroTypeVariation::Signed)
        .rustified_enum("point_conversion_form_t")
        .allowlist_file(".*/openssl/[^/]+\\.h")
        .allowlist_recursively(false)
        .blocklist_function("BIO_vsnprintf")
        .blocklist_function("OPENSSL_vasprintf")
        .wrap_static_fns(true)
        .wrap_static_fns_path(out_dir.join("boring_static_wrapper").display().to_string())
        .layout_tests(false)
        .header_contents("includes.h", INCLUDES);

    for include_dir in include_dirs {
        builder = builder
            .clang_arg("-I")
            .clang_arg(include_dir.display().to_string());
    }

    builder
        .generate()
        .unwrap()
        .write_to_file(out_dir.join("bindgen.rs"))
        .unwrap();

    fs::File::create(out_dir.join("boring_static_wrapper.h"))
        .expect("Failed to create boring_static_wrapper.h")
        .write_all(INCLUDES.as_bytes())
        .expect("Failed to write contents to boring_static_wrapper.h");

    cc::Build::new()
        .file(out_dir.join("boring_static_wrapper.c"))
        .includes(include_dirs)
        .flag("-include")
        .flag(
            &out_dir
                .join("boring_static_wrapper.h")
                .display()
                .to_string(),
        )
        .compile("boring_static_wrapper");
}

#[cfg(not(feature = "bindgen"))]
pub fn run_boringssl(include_dirs: &[PathBuf]) {
    let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());

    fs::File::create(out_dir.join("boring_static_wrapper.h"))
        .expect("Failed to create boring_static_wrapper.h")
        .write_all(INCLUDES.as_bytes())
        .expect("Failed to write contents to boring_static_wrapper.h");

    let mut bindgen_cmd = process::Command::new("bindgen");
    bindgen_cmd
        .arg("-o")
        .arg(out_dir.join("bindgen.rs"))
        // Must be a valid version from
        // https://docs.rs/bindgen/latest/bindgen/enum.RustTarget.html
        .arg("--rust-target=1.47")
        .arg("--ctypes-prefix=::libc")
        .arg("--raw-line=use libc::*;")
        .arg("--no-derive-default")
        .arg("--enable-function-attribute-detection")
        .arg("--default-macro-constant-type=signed")
        .arg("--rustified-enum=point_conversion_form_t")
        .arg("--allowlist-file=.*/openssl/[^/]+\\.h")
        .arg("--no-recursive-allowlist")
        .arg("--blocklist-function=BIO_vsnprintf")
        .arg("--blocklist-function=OPENSSL_vasprintf")
        .arg("--experimental")
        .arg("--wrap-static-fns")
        .arg("--wrap-static-fns-path")
        .arg(out_dir.join("boring_static_wrapper").display().to_string())
        .arg("--no-layout-tests")
        .arg(out_dir.join("boring_static_wrapper.h"))
        .arg("--")
        .arg(format!("--target={}", env::var("TARGET").unwrap()));

    for include_dir in include_dirs {
        bindgen_cmd.arg("-I").arg(include_dir.display().to_string());
    }

    let result = bindgen_cmd.status().expect("bindgen failed to execute");
    assert!(result.success());

    cc::Build::new()
        .file(out_dir.join("boring_static_wrapper.c"))
        .includes(include_dirs)
        .flag("-include")
        .flag(
            &out_dir
                .join("boring_static_wrapper.h")
                .display()
                .to_string(),
        )
        .compile("boring_static_wrapper");
}

#[derive(Debug)]
struct OpensslCallbacks;

#[cfg(feature = "bindgen")]
impl ParseCallbacks for OpensslCallbacks {
    // for now we'll continue hand-writing constants
    fn will_parse_macro(&self, _name: &str) -> MacroParsingBehavior {
        MacroParsingBehavior::Ignore
    }

    fn item_name(&self, original_item_name: &str) -> Option<String> {
        match original_item_name {
            // Our original definitions of these are wrong, so rename to avoid breakage
            "CRYPTO_EX_new"
            | "CRYPTO_EX_dup"
            | "CRYPTO_EX_free"
            | "BIO_meth_set_write"
            | "BIO_meth_set_read"
            | "BIO_meth_set_puts"
            | "BIO_meth_set_ctrl"
            | "BIO_meth_set_create"
            | "BIO_meth_set_destroy"
            | "CRYPTO_set_locking_callback"
            | "CRYPTO_set_id_callback"
            | "SSL_CTX_set_tmp_dh_callback"
            | "SSL_set_tmp_dh_callback"
            | "SSL_CTX_set_tmp_ecdh_callback"
            | "SSL_set_tmp_ecdh_callback"
            | "SSL_CTX_callback_ctrl"
            | "SSL_CTX_set_alpn_select_cb" => Some(format!("{}__fixed_rust", original_item_name)),
            _ => None,
        }
    }
}