use std::path::Path;

#[test]
fn no_host_imports() {
    let wasm_path = "target/wasm32-unknown-unknown/release/docs_core.wasm";

    // DOCS_REQUIRE_WASM=1 is set by the CI gate, which always builds the
    // wasm artifact before running this test — so under the gate a missing
    // artifact is a real failure, not something to shrug off. Left unset,
    // a bare `cargo test` on a fresh clone (no wasm build yet) still skips,
    // so local iteration on the native tests isn't forced to build wasm
    // first.
    let require_wasm = std::env::var("DOCS_REQUIRE_WASM").as_deref() == Ok("1");

    if !Path::new(wasm_path).exists() {
        if require_wasm {
            panic!(
                "FAILED (DOCS_REQUIRE_WASM=1): wasm artifact not found at {}. \
                 The gate must build it before running this test.",
                wasm_path
            );
        }
        eprintln!(
            "SKIPPED (DOCS_REQUIRE_WASM unset): wasm artifact not found at {}. \
             Run ./scripts/build-wasm.sh first.",
            wasm_path
        );
        return;
    }

    let wasm_bytes = std::fs::read(wasm_path).expect("Failed to read wasm file");
    let parser = wasmparser::Parser::new(0);

    let mut imports = Vec::new();

    for payload in parser.parse_all(&wasm_bytes) {
        let payload = payload.expect("Failed to parse wasm module");

        if let wasmparser::Payload::ImportSection(reader) = payload {
            let import_reader = reader.into_imports();
            for import_result in import_reader {
                let import = import_result.expect("Failed to parse import");
                imports.push(format!("{}.{}", import.module, import.name));
            }
        }
    }

    if !imports.is_empty() {
        panic!(
            "WASM module has host imports (breaks Go/wazero compatibility):\n  {}",
            imports.join("\n  ")
        );
    }

    eprintln!("PASSED (checked {} bytes, 0 imports)", wasm_bytes.len());
}