//! Build script — compiles bundled Java SMS sources to `classes.dex`.
//!
//! Pipeline:
//!   1. `javac` compiles each `.java` against `android.jar` → `.class` files.
//!   2. `d8` converts the `.class` files into a single `classes.dex` in `OUT_DIR`.
//!
//! No-op on non-Android targets.

use std::{env, fs, path::PathBuf};

const JAVA_FILES: &[&str] = &[
    "src/android/SmsReceiver.java",
    "src/android/SmsForegroundService.java",
    "src/android/BootReceiver.java",
];

fn main() {
    let target_os = env::var("CARGO_CFG_TARGET_OS").unwrap();

    if target_os == "android" {
        for f in JAVA_FILES {
            println!("cargo:rerun-if-changed={f}");
        }

        let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
        let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());

        if env::var("JAVA_SOURCE_VERSION").is_err() {
            env::set_var("JAVA_SOURCE_VERSION", "11");
        }
        if env::var("JAVA_TARGET_VERSION").is_err() {
            env::set_var("JAVA_TARGET_VERSION", "11");
        }

        let android_jar_path =
            android_build::android_jar(None).expect("Failed to find android.jar");

        let mut java = android_build::JavaBuild::new();
        java.class_path(android_jar_path.clone())
            .classes_out_dir(out_dir.clone());

        for rel in JAVA_FILES {
            java.file(manifest_dir.join(rel));
        }

        assert!(
            java.compile()
                .expect("failed to acquire exit status for javac invocation")
                .success(),
            "javac invocation failed"
        );

        let d8_jar_path =
            android_build::android_d8_jar(None).expect("Failed to find d8.jar");

        let class_root = out_dir.join("robius").join("trigger");
        let mut class_files: Vec<PathBuf> = Vec::new();
        if let Ok(entries) = fs::read_dir(&class_root) {
            for entry in entries.flatten() {
                let path = entry.path();
                if path.extension().and_then(|e| e.to_str()) == Some("class") {
                    class_files.push(path);
                }
            }
        }
        assert!(
            !class_files.is_empty(),
            "no .class files found in {class_root:?} — javac may have failed silently"
        );

        let mut run = android_build::JavaRun::new();
        run.class_path(d8_jar_path)
            .main_class("com.android.tools.r8.D8")
            .arg("--classpath")
            .arg(android_jar_path)
            .arg("--output")
            .arg(&out_dir);

        for class_file in &class_files {
            run.arg(class_file);
        }

        assert!(
            run.run()
                .expect("failed to acquire exit status for java d8.jar invocation")
                .success(),
            "java d8.jar invocation failed"
        );
    }
}