use std::env;
use std::error::Error;
use std::fs;
use std::io::{Read, Write};
use std::path::PathBuf;
use std::process::Command;

fn main() -> Result<(), Box<dyn Error>> {
    if env::var("DOCS_RS").is_err() & !cfg!(feature = "sitk_no_build") {
        let sitk_dir = PathBuf::from("SimpleITK");

        // use cmake to compile the SimpleITK C++ code
        let dst = cmake::Config::new(sitk_dir.join("SuperBuild"))
            .no_build_target(true)
            .define("ITK_SKIP_PATH_LENGTH_CHECKS", "ON")
            .define("BUILD_EXAMPLES", "OFF")
            .define("BUILD_TESTING", "OFF")
            .define("WRAP_CSHARP", "OFF")
            .define("WRAP_JAVA", "OFF")
            .define("WRAP_LUA", "OFF")
            .define("WRAP_R", "OFF")
            .define("WRAP_RUBY", "OFF")
            .define("WRAP_TCL", "OFF")
            .define("WRAP_PYTHON", "OFF")
            .define("WRAP_DEFAULT", "OFF")
            .define("SimpleITK_USE_ELASTIX", "ON")
            .build();

        // there does not seem to be any way to tell cargo to group libraries together
        // when linking, so we group all objects together in three big static libraries
        let merged_lib = cmake::Config::new("merged_lib")
            .out_dir(dst.join("merged_lib"))
            .no_build_target(true)
            .build();

        let mut b = autocxx_build::Builder::new(
            "src/lib.rs",
            ["cxx", dst.join("include/SimpleITK-3.0").to_str().unwrap()],
        )
        .extra_clang_args(&["-std=c++17"])
        .build()?;
        b.flag("-std=c++17").compile("sitk_autocxx");

        cc::Build::new()
            .include(dst.join("include/SimpleITK-3.0"))
            .file("cxx/ffi_extra.cxx")
            .compile("sitk_ffi_extra");

        let cxx_file = dst.join("autocxx-build-dir/rs/autocxx-ffi-default-gen.rs");
        let mut cxx = String::new();
        let _ = fs::File::open(&cxx_file)?.read_to_string(&mut cxx)?;
        let ra = regex::Regex::new(r"\s*(#|\s(fn|use|mod|pub|struct|enum)\s)\s*")?;
        let rb = regex::Regex::new(r"\s(;)\s")?;
        let pointer = regex::Regex::new(r"pub type pointer = root\s+::\s+pointer;")?;
        let cpp_string = regex::Regex::new(r"pub mod simple \{")?;
        let rb_tree = regex::Regex::new(
            r"pub type _Rb_tree_insert_return_type = root :: std :: _Node_insert_return < _Iterator , _NodeHandle >;",
        )?;

        {
            let mut f = fs::OpenOptions::new()
                .write(true)
                .truncate(true)
                .open(&cxx_file)?;
            write!(
                f,
                "#[allow(unused_imports)]\n#[allow(unsafe_op_in_unsafe_fn)]\n#[allow(clippy::missing_safety_doc)]\n"
            )?;
            let cxx = ra.replace_all(&cxx, "\n$1");
            let cxx = rb.replace_all(&cxx, "$1\n");
            let cxx = pointer.replace_all(&cxx, r"// $0");
            let cxx = rb_tree.replace_all(&cxx, r"// $0");
            let cxx =
                cpp_string.replace_all(&cxx, "pub mod simple {\nuse crate::ffi::ToCppString;");
            write!(f, "{}", cxx)?;
        }
        if cfg!(feature = "copy_autocxx_src") {
            fs::copy(dst.join(&cxx_file), "src/autocxx-ffi-default-gen_unfmt.rs")?;
            Command::new("rustfmt").arg(&cxx_file).status()?;
            fs::copy(dst.join(&cxx_file), "src/autocxx-ffi-default-gen.rs")?;
        }
        println!("cargo:warning=merged_lib={}", merged_lib.join("build").display());
        println!("cargo:rustc-link-search={}", merged_lib.join("build").display());
        println!("cargo:rustc-link-lib=static=sitk_ffi_extra");
        println!("cargo:rustc-link-lib=static=sitk");
        println!("cargo:rustc-link-lib=static=elastix");
        println!("cargo:rustc-link-lib=static=itk");
        println!("cargo:rerun-if-changed=build.rs");
        println!("cargo:rerun-if-changed=src/lib.rs");
        println!("cargo:rerun-if-changed=cxx/ffi_extra.h");
        println!("cargo:rerun-if-changed=cxx/ffi_extra.cxx");
    } else {
        let dst = PathBuf::from(env::var("OUT_DIR")?);
        fs::create_dir_all(dst.join("autocxx-build-dir/rs"))?;
        fs::copy(
            "src/autocxx-ffi-default-gen.rs",
            dst.join("autocxx-build-dir/rs/autocxx-ffi-default-gen.rs"),
        )?;
    }
    Ok(())
}