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

const TARGET_MANIFESTS: &[&str] =
    &["crates/console/prometeu-bytecode/Cargo.toml", "crates/console/prometeu-vm/Cargo.toml"];

const FORBIDDEN_DEPENDENCY_FRAGMENTS: &[&str] = &["compiler", "frontend"];

#[test]
fn pbx_and_pvm_crates_must_not_depend_on_compiler_or_frontend_crates() {
    let workspace_root = find_workspace_root().expect("runtime workspace root");
    let mut violations = Vec::new();

    for relative_path in TARGET_MANIFESTS {
        let manifest_path = workspace_root.join(relative_path);
        let manifest = fs::read_to_string(&manifest_path)
            .unwrap_or_else(|error| panic!("failed to read {}: {error}", manifest_path.display()));

        for dependency in dependency_names(&manifest) {
            let normalized = dependency.to_ascii_lowercase();
            if FORBIDDEN_DEPENDENCY_FRAGMENTS.iter().any(|fragment| normalized.contains(fragment)) {
                violations.push(format!("{relative_path}: forbidden dependency `{dependency}`"));
            }
        }
    }

    assert!(
        violations.is_empty(),
        "PBX/PVM crates must remain independent of compiler and frontend crates:\n{}",
        violations.join("\n")
    );
}

fn dependency_names(manifest: &str) -> Vec<&str> {
    let mut names = Vec::new();
    let mut in_dependency_section = false;

    for raw_line in manifest.lines() {
        let line = raw_line.trim();
        if line.starts_with('[') && line.ends_with(']') {
            let section = &line[1..line.len() - 1];
            in_dependency_section = section == "dependencies"
                || section == "dev-dependencies"
                || section == "build-dependencies"
                || section.ends_with(".dependencies")
                || section.ends_with(".dev-dependencies")
                || section.ends_with(".build-dependencies");
            continue;
        }

        if !in_dependency_section || line.is_empty() || line.starts_with('#') {
            continue;
        }

        if let Some((name, _)) = line.split_once('=') {
            names.push(name.trim().trim_matches('"'));
        }
    }

    names
}

fn find_workspace_root() -> Option<PathBuf> {
    let mut cursor = Path::new(env!("CARGO_MANIFEST_DIR")).to_path_buf();
    loop {
        let manifest = cursor.join("Cargo.toml");
        if fs::read_to_string(&manifest).is_ok_and(|contents| contents.contains("[workspace]")) {
            return Some(cursor);
        }
        if !cursor.pop() {
            return None;
        }
    }
}