use frontend::{DiagnosticKind, Span, TokenKind, lex};

#[test]
fn lexical_errors_keep_original_byte_ranges_after_multiple_tokens() {
    let prefix = "let 商品 = ";
    for (tail, offending, message) in [
        (
            "12.50名前 ;",
            "12.50名前",
            "unsupported numeric suffix or missing token separator",
        ),
        ("\"日\\q\" ;", "\\q", "unsupported string escape"),
        ("\"日\\🌸\" ;", "\\🌸", "unsupported string escape"),
        ("\"日\\\n\" ;", "\\\n", "unsupported string escape"),
        ("\"日\nrest\" ;", "\n", "unescaped newline or NUL in string"),
        ("\"日\rrest\" ;", "\r", "unescaped newline or NUL in string"),
        ("\"日\0rest\" ;", "\0", "unescaped newline or NUL in string"),
        ("\"未完", "\"未完", "unterminated string"),
        ("\"未完\\", "\"未完\\", "unterminated string"),
        ("🌸 ;", "🌸", "unexpected source character"),
    ] {
        let source = format!("{prefix}{tail}");
        let error = lex(&source).unwrap_err();
        let start = source.find(offending).unwrap();
        assert_eq!(error.kind, DiagnosticKind::Lexical, "{source:?}");
        assert_eq!(error.span, Span::new(start, start + offending.len()));
        assert_eq!(error.message, message, "{source:?}");
        assert!(error.expected.is_empty());
    }
}

#[test]
fn token_boundaries_distinguish_members_division_comments_and_string_contents() {
    let source = " \t// 前置\r\n商品.価格 / 12.50// 行末\0\n\"//実文\" \r\n// 終端";
    let tokens = lex(source).unwrap();
    let spellings: Vec<_> = tokens
        .iter()
        .map(|token| (token.kind, &source[token.span.start..token.span.end]))
        .collect();
    assert_eq!(
        spellings,
        vec![
            (TokenKind::Name, "商品"),
            (TokenKind::Dot, "."),
            (TokenKind::Name, "価格"),
            (TokenKind::Slash, "/"),
            (TokenKind::Number, "12.50"),
            (TokenKind::String, "\"//実文\""),
        ]
    );
    assert!(lex("").unwrap().is_empty());
    assert!(lex(" \t\r\n// 注釈\0").unwrap().is_empty());
}