//! The core builds from the standard library alone. A foreign crate could
//! bring floating point, hash maps or threads in through the back door.

// Tests may read files. The rules of core/clippy.toml apply to core/src.
#![allow(clippy::disallowed_methods)]

use std::fs;
use std::path::Path;

/// Every manifest section that may add a dependency, with the lines it
/// declares. Development dependencies are allowed, because they never reach
/// the game.
fn dependency_sections(manifest: &str) -> Vec<(String, Vec<String>)> {
    let mut sections: Vec<(String, Vec<String>)> = Vec::new();
    let mut inside = false;
    for line in manifest.lines() {
        let line = line.trim();
        if line.starts_with('[') {
            inside = line.contains("dependencies") && !line.contains("dev-dependencies");
            if inside {
                sections.push((line.to_owned(), Vec::new()));
            }
            continue;
        }
        if inside && !line.is_empty() && !line.starts_with('#') {
            if let Some((_, entries)) = sections.last_mut() {
                entries.push(line.to_owned());
            }
        }
    }
    sections
}

#[test]
fn the_core_has_no_dependencies() {
    let path = Path::new(env!("CARGO_MANIFEST_DIR")).join("Cargo.toml");
    let manifest = fs::read_to_string(&path).expect("the manifest is readable");
    for (header, entries) in dependency_sections(&manifest) {
        assert!(
            !header.contains("dependencies."),
            "the core declares a dependency table: {header}"
        );
        assert!(
            entries.is_empty(),
            "{header} of the core must stay empty, found: {entries:?}"
        );
    }
}

#[test]
fn dependency_sections_are_found_with_their_entries() {
    let manifest = "[package]\nname = \"x\"\n\n[dependencies]\n# a comment\nserde = \"1\"\n\n\
                    [dev-dependencies]\nproptest = \"1\"\n\n[dependencies.rand]\nversion = \"0.8\"\n";
    assert_eq!(
        dependency_sections(manifest),
        vec![
            (
                "[dependencies]".to_owned(),
                vec!["serde = \"1\"".to_owned()]
            ),
            (
                "[dependencies.rand]".to_owned(),
                vec!["version = \"0.8\"".to_owned()]
            ),
        ]
    );
}