use clap::CommandFactory;
use clap_complete::{generate_to, Shell};
use std::env;
use std::fs;
use std::path::{Path, PathBuf};
use std::process::Command;

#[path = "src/cli.rs"]
mod cli;

fn apply_template(template: &Path) -> String {
    let outdir =
        PathBuf::from(env::var_os("OUT_DIR").expect("OUT_DIR environment variable not defined"));
    fs::create_dir_all(&outdir).expect("unable to create out dir");

    let profile = env::var_os("PROFILE").expect("PROFILE environment variable not defined");
    let mdevctl_bin_path = PathBuf::from("target").join(profile).join("mdevctl");
    let version = env::var("CARGO_PKG_VERSION").expect("CARGO_PKG_VERSION not set");

    fs::read_to_string(template)
        .unwrap_or_else(|_| panic!("Failed to read template {:?}", template))
        .replace("@@mdevctl@@", mdevctl_bin_path.to_str().unwrap())
        .replace("@@outdir@@", outdir.to_str().unwrap())
        .replace("@@mdevctl_version@@", version.as_str())
        .replace(
            "@@generated_notice@@",
            format!(
                "# DO NOT EDIT\n# This file is automatically generated from {:?}",
                template
            )
            .as_str(),
        )
}

fn generate_manpage<P: AsRef<Path>>(outdir: P) {
    let rst2man = env::var("RST2MAN").unwrap_or_else(|_| "rst2man".to_owned());
    let infile = PathBuf::from("mdevctl.rst");
    println!("cargo:rerun-if-changed={}", infile.to_str().unwrap());
    let outfile = outdir.as_ref().join("mdevctl.8");
    Command::new(rst2man)
        .arg(infile)
        .arg(outfile)
        .output()
        .expect("Unable to generate manpage. Is 'rst2man' installed? You can specify a custom 'rst2man' executable by setting the RST2MAN environment variable.");
}

fn generate_completion(cmd: &mut clap::Command, outdir: &PathBuf) {
    let name = cmd.get_name().to_string();
    generate_to(Shell::Bash, cmd, name, outdir).expect("Unable to generate shell completion files");
}

fn main() {
    let outdir =
        PathBuf::from(env::var_os("OUT_DIR").expect("OUT_DIR environment variable not defined"));

    // generate bash completions for both executables
    generate_completion(&mut cli::MdevctlCommands::command(), &outdir);
    generate_completion(&mut cli::LsmdevOptions::command(), &outdir);

    // generate manpage
    generate_manpage(outdir);

    // generate a rpm spec file from the spec.in template
    let rpm_in = PathBuf::from("mdevctl.spec.in");
    let rpm_out = PathBuf::from(rpm_in.file_stem().unwrap());
    let contents = apply_template(&rpm_in);
    std::fs::write(&rpm_out, contents).unwrap_or_else(|_| panic!("Failed to write {:?}", rpm_out));
    println!("cargo:rerun-if-changed={}", rpm_in.to_str().unwrap());

    // Generate a makefile for installing the auxiliary files based on the Makefile.in template
    let makefile_in = PathBuf::from("Makefile.in");
    let makefile_out = PathBuf::from(makefile_in.file_stem().unwrap());
    let contents = apply_template(&makefile_in);

    // FIXME: build.rs really shouldn't touch anything outside of OUT_DIR, but generating the
    // Makefile in a directory named ./target/$PROFILE/build/mdevctl-$HASH/out/ is very
    // undiscoverable and kind of defeats the purpose. Need to find a better solution.
    std::fs::write(&makefile_out, contents)
        .unwrap_or_else(|_| panic!("Failed to write {:?}", makefile_out));
    println!("cargo:rerun-if-changed={}", makefile_in.to_str().unwrap());
}