extern crate cc;
extern crate regex;

fn main() {
    build::main()
}

#[cfg(feature = "docs-only")]
mod build {
    pub fn main() {}
}

#[cfg(not(feature = "docs-only"))]
mod build {
    use regex::Regex;
    use std::env;
    use std::fs;
    use std::path::Path;
    use std::process::Command;

    pub fn main() {
        let out_dir = env::var("OUT_DIR").unwrap();
        let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();

        let out_dir = Path::new(&out_dir);
        let native_from = Path::new(&crate_dir).join("native");
        let native_to = Path::new(&out_dir).join("native");

        // 1. Copy the native runtime library into the build directory.
        copy_native_library(&native_from, &native_to);

        // 2. Build the object file from source using node-gyp.
        build_object_file(&native_to);

        // 3. Link the library from the object file using gcc.
        link_library(&native_to);

        // 4. Copy native build artifacts
        copy_build_artifacts(&native_to, &out_dir);

        // Rebuild if any of these environment variables change
        println!("cargo:rerun-if-env-changed=npm_config_target");
        println!("cargo:rerun-if-env-changed=npm_config_arch");
        println!("cargo:rerun-if-env-changed=npm_config_target_arch");
    }

    fn copy_files(dir_from: impl AsRef<Path>, dir_to: impl AsRef<Path>) {
        for entry in fs::read_dir(dir_from.as_ref()).unwrap() {
            let entry = entry.unwrap();

            if entry.file_type().unwrap().is_dir() {
                continue;
            }

            let file_name = entry.file_name();

            let from = dir_from.as_ref().join(&file_name);
            let to = dir_to.as_ref().join(&file_name);

            fs::copy(from, to).unwrap();
        }
    }

    fn copy_native_library(native_from: impl AsRef<Path>, native_to: impl AsRef<Path>) {
        let native_from = native_from.as_ref();
        let native_to = native_to.as_ref();

        let src_from = native_from.join("src");
        let src_to = native_to.join("src");

        fs::create_dir_all(&src_to).unwrap();

        copy_files(&native_from, &native_to);
        copy_files(&src_from, &src_to);
    }

    #[cfg(unix)]
    fn npm(cwd: &Path) -> Command {
        let mut cmd = Command::new("npm");
        cmd.current_dir(cwd);
        cmd
    }

    #[cfg(windows)]
    fn npm(cwd: &Path) -> Command {
        let mut cmd = Command::new("cmd.exe");
        cmd.args(&["/C", "npm"]);
        cmd.current_dir(cwd);
        cmd
    }

    // The node-gyp build output includes platform information in a string
    // that looks like:
    //
    //     gyp verb architecture ia32
    fn parse_node_arch(node_gyp_output: &str) -> String {
        let version_regex =
            Regex::new(r"gyp verb architecture (?P<arch>ia32|x64|arm|arm64)").unwrap();
        let captures = version_regex.captures(&node_gyp_output).unwrap();
        String::from(&captures["arch"])
    }

    // The node-gyp output includes the root directory of shared resources
    // for the Node installation in a string that looks like:
    //
    //     '-Dnode_root_dir=C:\\Users\\dherman\\.node-gyp\\8.3.0'
    fn parse_node_root_dir(node_gyp_output: &str) -> &str {
        let node_root_dir_flag_pattern = "'-Dnode_root_dir=";
        let node_root_dir_start_index = node_gyp_output
            .find(node_root_dir_flag_pattern)
            .map(|i| i + node_root_dir_flag_pattern.len())
            .expect("Couldn't find node_root_dir in node-gyp output.");
        let node_root_dir_end_index = node_gyp_output[node_root_dir_start_index..]
            .find('\'')
            .unwrap()
            + node_root_dir_start_index;
        &node_gyp_output[node_root_dir_start_index..node_root_dir_end_index]
    }

    // The node-gyp output includes the name of the shared Node library file.
    // In NPM versions <= v5.0.3, this was just the filename by itself, e.g.:
    //
    //     '-Dnode_lib_file=node.lib'
    //
    // In NPM versions >= v5.3.0, this was a templated absolute path with a
    // reference to a gyp variable, e.g.:
    //
    //     '-Dnode_lib_file=C:\\Users\\dherman\\.node-gyp\\8.3.0\\<(target_arch)\\node.lib'
    //
    // Either way, we simply extract the value here. The `neon-build` crate
    // processes it further.
    fn parse_node_lib_file(node_gyp_output: &str) -> &str {
        let node_lib_file_flag_pattern = "'-Dnode_lib_file=";
        let node_lib_file_start_index = node_gyp_output
            .find(node_lib_file_flag_pattern)
            .map(|i| i + node_lib_file_flag_pattern.len())
            .expect("Couldn't find node_lib_file in node-gyp output.");
        let node_lib_file_end_index = node_gyp_output[node_lib_file_start_index..]
            .find('\'')
            .unwrap()
            + node_lib_file_start_index;
        &node_gyp_output[node_lib_file_start_index..node_lib_file_end_index]
    }

    fn build_object_file(native_dir: &Path) {
        if cfg!(windows) {
            // Downcase all the npm environment variables to ensure they are read by node-gyp.
            for (key, value) in env::vars() {
                if key.starts_with("NPM_CONFIG") {
                    env::remove_var(&key);
                    env::set_var(key.to_lowercase(), value);
                }
            }
        }

        // Ensure that all package.json dependencies and dev dependencies are installed.
        npm(native_dir)
            .args(&["install", "--silent"])
            .status()
            .expect("Failed to run \"npm install\" for neon-sys!");

        // Run `node-gyp configure` in verbose mode to read node_root_dir on Windows.
        let output = npm(native_dir)
            .args(&[
                "run",
                if debug() {
                    "configure-debug"
                } else {
                    "configure-release"
                },
            ])
            .output()
            .expect("Failed to run \"node-gyp configure\" for neon-sys!");

        if !output.status.success() {
            panic!(
                "Failed to run \"node-gyp configure\" for neon-sys!\n Out: {}\n Err: {}",
                String::from_utf8_lossy(&output.stdout),
                String::from_utf8_lossy(&output.stderr)
            );
        }

        if cfg!(windows) {
            let node_gyp_output = String::from_utf8_lossy(&output.stderr);
            println!(
                "cargo:node_root_dir={}",
                parse_node_root_dir(&node_gyp_output)
            );
            println!(
                "cargo:node_lib_file={}",
                parse_node_lib_file(&node_gyp_output)
            );
        }

        // Run `node-gyp build`.
        let build_output = npm(native_dir)
            .args(&[
                "run",
                if debug() {
                    "build-debug"
                } else {
                    "build-release"
                },
            ])
            .output()
            .expect("Failed to run \"node-gyp build\" for neon-sys!");

        if !build_output.status.success() {
            panic!(
                "Failed to run \"node-gyp build\" for neon-sys!\n Out: {}\n Err: {}",
                String::from_utf8_lossy(&build_output.stdout),
                String::from_utf8_lossy(&build_output.stderr)
            );
        }

        let node_gyp_build_output = String::from_utf8_lossy(&build_output.stderr);
        println!(
            "cargo:node_arch={}",
            parse_node_arch(&node_gyp_build_output)
        );
    }

    // Link the built object file into a static library.
    fn link_library(native_dir: &Path) {
        let configuration = if debug() { "Debug" } else { "Release" };

        let object_path = if cfg!(unix) {
            native_dir
                .join("build")
                .join(configuration)
                .join("obj.target")
                .join("neon")
                .join("src")
                .join("neon.o")
        } else {
            let neon_dir = native_dir
                .join("build")
                .join(configuration)
                .join("obj")
                .join("neon");
            let object_path = neon_dir.join("src").join("neon.obj");
            if object_path.exists() {
                object_path
            } else {
                neon_dir.join("neon.obj")
            }
        };

        cc::Build::new()
            .cpp(true)
            .object(object_path)
            .compile("libneon.a");
    }

    #[cfg(unix)]
    fn copy_build_artifacts(_native_dir: &Path, _out_dir: &Path) {}

    #[cfg(windows)]
    fn copy_build_artifacts(native_dir: &Path, out_dir: &Path) {
        let configuration = if debug() { "Debug" } else { "Release" };
        let win_delay_file = "win_delay_load_hook.obj";
        let win_delay_dest = out_dir.join(win_delay_file);
        let win_delay_source = native_dir
            .join("build")
            .join(configuration)
            .join("obj")
            .join("neon")
            .join(win_delay_file);

        // Win delay hook is only needed for electron, warn instead of crash if not found
        if let Err(err) = fs::copy(win_delay_source, win_delay_dest) {
            if err.kind() == std::io::ErrorKind::NotFound {
                eprintln!("warning: {} could not be found", win_delay_file);
            } else {
                panic!("{:?}", err);
            }
        }
    }

    fn debug() -> bool {
        match env::var("DEBUG") {
            Ok(s) => s == "true",
            Err(_) => false,
        }
    }
}