use std::env;
use wasmer::compiler::Backend;

pub fn get_backend() -> Option<Backend> {
    #[cfg(feature = "backend-cranelift")]
    {
        if let Ok(v) = env::var("WASMER_TEST_CRANELIFT") {
            if v == "1" {
                return Some(Backend::Cranelift);
            }
        }
    }
    #[cfg(feature = "backend-llvm")]
    {
        if let Ok(v) = env::var("WASMER_TEST_LLVM") {
            if v == "1" {
                return Some(Backend::LLVM);
            }
        }
    }
    #[cfg(feature = "backend-singlepass")]
    {
        if let Ok(v) = env::var("WASMER_TEST_SINGLEPASS") {
            if v == "1" {
                return Some(Backend::Singlepass);
            }
        }
    }

    None
}

macro_rules! assert_emscripten_output {
    ($file:expr, $name:expr, $args:expr, $expected:expr) => {{

        use wasmer_emscripten::{
            EmscriptenGlobals,
            generate_emscripten_env,
        };
        use crate::utils::stdio::StdioCapturer;

        let wasm_bytes = include_bytes!($file);
        let backend = $crate::emtests::_common::get_backend().expect("Please set one of `WASMER_TEST_CRANELIFT`, `WASMER_TEST_LLVM`, or `WASMER_TEST_SINGELPASS` to `1`.");
        let compiler = wasmer::compiler::compiler_for_backend(backend).expect("The desired compiler was not found!");

        let module = wasmer::compiler::compile_with_config_with(&wasm_bytes[..], Default::default(), &*compiler).expect("WASM can't be compiled");

        let mut emscripten_globals = EmscriptenGlobals::new(&module).expect("globals are valid");
        let import_object = generate_emscripten_env(&mut emscripten_globals);

        let mut instance = module.instantiate(&import_object)
            .map_err(|err| format!("Can't instantiate the WebAssembly module: {:?}", err)).unwrap(); // NOTE: Need to figure what the unwrap is for ??

        let capturer = StdioCapturer::new();

        wasmer_emscripten::run_emscripten_instance(
            &module,
            &mut instance,
            &mut emscripten_globals,
            $name,
            $args,
            None,
            vec![],
        ).expect("run_emscripten_instance finishes");

        let output = capturer.end().unwrap().0;
        let expected_output = include_str!($expected);

        assert!(
            output.contains(expected_output),
            "Output: `{}` does not contain expected output: `{}`",
            output,
            expected_output
        );
    }};
}

// pub fn assert_emscripten_output(wasm_bytes: &[u8], raw_expected_str: &str) {
//     use wasmer_clif_backend::CraneliftCompiler;
//     use wasmer_emscripten::{generate_emscripten_env, stdio::StdioCapturer, EmscriptenGlobals};

//     let module = wasmer::compiler::compile_with(&wasm_bytes[..], &CraneliftCompiler::new())
//         .expect("WASM can't be compiled");

//     let mut emscripten_globals = EmscriptenGlobals::new(&module);
//     let import_object = generate_emscripten_env(&mut emscripten_globals);
//     let mut instance = module
//         .instantiate(&import_object)
//         .map_err(|err| format!("Can't instantiate the WebAssembly module: {:?}", err))
//         .unwrap();

//     let capturer = StdioCapturer::new();

//     wasmer_emscripten::run_emscripten_instance(&module, &mut instance, "test", vec![])
//         .expect("run_emscripten_instance finishes");

//     let raw_output_string = capturer.end().unwrap().0;

//     // trim the strings to avoid cross-platform line ending and white space issues
//     let output = raw_output_string.trim();
//     let expected_output = raw_expected_str.trim();

//     let contains_output = output.contains(expected_output);

//     assert!(
//         contains_output,
//         "Output: `{}` does not contain expected output: `{}`",
//         output, expected_output
//     );
// }