extern crate autotools;
extern crate bindgen;

use std::{
    env, fs,
    path::{Path, PathBuf},
    process::Command,
};

fn check_installed(name: &str) -> anyhow::Result<()> {
    let check = Command::new(name).arg("--version").output();

    match check {
        Ok(output) => {
            if !output.status.success() {
                return Err(anyhow::anyhow!(
                    "{} is required, but it's not installed or not in PATH.",
                    name
                ));
            }
        }
        Err(_) => {
            return Err(anyhow::anyhow!(
                "{} is required, but it's not installed or not in PATH.",
                name
            ));
        }
    }

    Ok(())
}

fn main() -> anyhow::Result<()> {
    // Check if autoconf is installed
    check_installed("autoconf")?;
    check_installed("automake")?;

    let out_dir = env::var("OUT_DIR").map(PathBuf::from)?;
    let src_dir = Path::new(env!("CARGO_MANIFEST_DIR")).join("jq");
    let build_dir = out_dir.join("jq_build");

    // Copy the contents of the src_dir to build_dir within OUT_DIR
    // to avoid modifying the source directory during the build process.
    // This ensures compliance with Cargo's policy that build scripts
    // should not modify anything outside of OUT_DIR.
    if build_dir.exists() {
        fs::remove_dir_all(&build_dir)?;
    }
    fs::create_dir(&build_dir)?;
    for entry in walkdir::WalkDir::new(&src_dir) {
        let entry = entry?;
        let target_path = build_dir.join(entry.path().strip_prefix(&src_dir)?);
        if entry.file_type().is_dir() {
            fs::create_dir_all(target_path)?;
        } else {
            fs::copy(entry.path(), target_path)?;
        }
    }

    // It seems that modifying the timestamp of the lexer.c file by copying
    // it to the target directory is necessary to circumvent an error that goes something like:
    //   cc1: fatal error: src/lexer.c: No such file or directory compilation terminated.
    let lexer_src = src_dir.join("src/lexer.c");
    let lexer_target = build_dir.join("src/lexer.c");
    fs::copy(lexer_src, lexer_target)?;
    // parser.c also
    //   error: src/parser.c: No such file or directory
    let parser_src = src_dir.join("src/parser.c");
    let parser_target = build_dir.join("src/parser.c");
    fs::copy(parser_src, parser_target)?;

    // See https://github.com/jqlang/jq/tree/jq-1.7.1?#instructions
    autotools::Config::new(&build_dir)
        .reconf("-i")
        .out_dir(&out_dir)
        .with("oniguruma", Some("builtin"))
        .make_args(vec![
            // See https://github.com/jqlang/jq/issues/1936
            "CPPFLAGS=-D_REENTRANT".into(),
        ])
        .build();

    let lib_dir = out_dir.join("lib");
    println!("cargo:rustc-link-search=native={}", lib_dir.display());
    for lib in &["onig", "jq"] {
        println!("cargo:rustc-link-lib=static={}", lib);
    }

    let bindings = bindgen::Builder::default()
        .header("jq/src/jq.h")
        .generate()?;

    bindings.write_to_file(out_dir.join("bindings.rs"))?;

    Ok(())
}