//! Tests for the lexer.
#![allow(clippy::indexing_slicing)]

use super::regex::RegExpFlags;
use super::token::Numeric;
use super::*;
use super::{Error, Position};
use crate::syntax::ast::Keyword;

fn span(start: (u32, u32), end: (u32, u32)) -> Span {
    Span::new(Position::new(start.0, start.1), Position::new(end.0, end.1))
}

fn expect_tokens<R>(lexer: &mut Lexer<R>, expected: &[TokenKind])
where
    R: Read,
{
    for expect in expected.iter() {
        assert_eq!(&lexer.next().unwrap().unwrap().kind(), &expect);
    }

    assert!(
        lexer.next().unwrap().is_none(),
        "Unexpected extra token lexed at end of input"
    );
}

#[test]
fn check_single_line_comment() {
    let s1 = "var \n//This is a comment\ntrue";
    let mut lexer = Lexer::new(s1.as_bytes());

    let expected = [
        TokenKind::Keyword(Keyword::Var),
        TokenKind::LineTerminator,
        TokenKind::LineTerminator,
        TokenKind::BooleanLiteral(true),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn check_multi_line_comment() {
    let s = "var /* await \n break \n*/ x";
    let mut lexer = Lexer::new(s.as_bytes());

    let expected = [
        TokenKind::Keyword(Keyword::Var),
        TokenKind::LineTerminator,
        TokenKind::identifier("x"),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn check_string() {
    let s = "'aaa' \"bbb\"";
    let mut lexer = Lexer::new(s.as_bytes());

    let expected = [
        TokenKind::string_literal("aaa"),
        TokenKind::string_literal("bbb"),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn check_template_literal_simple() {
    let s = "`I'm a template literal`";
    let mut lexer = Lexer::new(s.as_bytes());

    assert_eq!(
        lexer.next().unwrap().unwrap().kind(),
        &TokenKind::template_literal("I'm a template literal")
    );
}

#[test]
fn check_template_literal_unterminated() {
    let s = "`I'm a template";
    let mut lexer = Lexer::new(s.as_bytes());

    lexer
        .next()
        .expect_err("Lexer did not handle unterminated literal with error");
}

#[test]
fn check_punctuators() {
    // https://tc39.es/ecma262/#sec-punctuators
    let s = "{ ( ) [ ] . ... ; , < > <= >= == != === !== \
             + - * % -- << >> >>> & | ^ ! ~ && || ? : \
             = += -= *= &= **= ++ ** <<= >>= >>>= &= |= ^= =>";
    let mut lexer = Lexer::new(s.as_bytes());

    let expected = [
        TokenKind::Punctuator(Punctuator::OpenBlock),
        TokenKind::Punctuator(Punctuator::OpenParen),
        TokenKind::Punctuator(Punctuator::CloseParen),
        TokenKind::Punctuator(Punctuator::OpenBracket),
        TokenKind::Punctuator(Punctuator::CloseBracket),
        TokenKind::Punctuator(Punctuator::Dot),
        TokenKind::Punctuator(Punctuator::Spread),
        TokenKind::Punctuator(Punctuator::Semicolon),
        TokenKind::Punctuator(Punctuator::Comma),
        TokenKind::Punctuator(Punctuator::LessThan),
        TokenKind::Punctuator(Punctuator::GreaterThan),
        TokenKind::Punctuator(Punctuator::LessThanOrEq),
        TokenKind::Punctuator(Punctuator::GreaterThanOrEq),
        TokenKind::Punctuator(Punctuator::Eq),
        TokenKind::Punctuator(Punctuator::NotEq),
        TokenKind::Punctuator(Punctuator::StrictEq),
        TokenKind::Punctuator(Punctuator::StrictNotEq),
        TokenKind::Punctuator(Punctuator::Add),
        TokenKind::Punctuator(Punctuator::Sub),
        TokenKind::Punctuator(Punctuator::Mul),
        TokenKind::Punctuator(Punctuator::Mod),
        TokenKind::Punctuator(Punctuator::Dec),
        TokenKind::Punctuator(Punctuator::LeftSh),
        TokenKind::Punctuator(Punctuator::RightSh),
        TokenKind::Punctuator(Punctuator::URightSh),
        TokenKind::Punctuator(Punctuator::And),
        TokenKind::Punctuator(Punctuator::Or),
        TokenKind::Punctuator(Punctuator::Xor),
        TokenKind::Punctuator(Punctuator::Not),
        TokenKind::Punctuator(Punctuator::Neg),
        TokenKind::Punctuator(Punctuator::BoolAnd),
        TokenKind::Punctuator(Punctuator::BoolOr),
        TokenKind::Punctuator(Punctuator::Question),
        TokenKind::Punctuator(Punctuator::Colon),
        TokenKind::Punctuator(Punctuator::Assign),
        TokenKind::Punctuator(Punctuator::AssignAdd),
        TokenKind::Punctuator(Punctuator::AssignSub),
        TokenKind::Punctuator(Punctuator::AssignMul),
        TokenKind::Punctuator(Punctuator::AssignAnd),
        TokenKind::Punctuator(Punctuator::AssignPow),
        TokenKind::Punctuator(Punctuator::Inc),
        TokenKind::Punctuator(Punctuator::Exp),
        TokenKind::Punctuator(Punctuator::AssignLeftSh),
        TokenKind::Punctuator(Punctuator::AssignRightSh),
        TokenKind::Punctuator(Punctuator::AssignURightSh),
        TokenKind::Punctuator(Punctuator::AssignAnd),
        TokenKind::Punctuator(Punctuator::AssignOr),
        TokenKind::Punctuator(Punctuator::AssignXor),
        TokenKind::Punctuator(Punctuator::Arrow),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn check_keywords() {
    // https://tc39.es/ecma262/#sec-keywords
    let s = "await break case catch class const continue debugger default delete \
             do else export extends finally for function if import in instanceof \
             new return super switch this throw try typeof var void while with yield";

    let mut lexer = Lexer::new(s.as_bytes());

    let expected = [
        TokenKind::Keyword(Keyword::Await),
        TokenKind::Keyword(Keyword::Break),
        TokenKind::Keyword(Keyword::Case),
        TokenKind::Keyword(Keyword::Catch),
        TokenKind::Keyword(Keyword::Class),
        TokenKind::Keyword(Keyword::Const),
        TokenKind::Keyword(Keyword::Continue),
        TokenKind::Keyword(Keyword::Debugger),
        TokenKind::Keyword(Keyword::Default),
        TokenKind::Keyword(Keyword::Delete),
        TokenKind::Keyword(Keyword::Do),
        TokenKind::Keyword(Keyword::Else),
        TokenKind::Keyword(Keyword::Export),
        TokenKind::Keyword(Keyword::Extends),
        TokenKind::Keyword(Keyword::Finally),
        TokenKind::Keyword(Keyword::For),
        TokenKind::Keyword(Keyword::Function),
        TokenKind::Keyword(Keyword::If),
        TokenKind::Keyword(Keyword::Import),
        TokenKind::Keyword(Keyword::In),
        TokenKind::Keyword(Keyword::InstanceOf),
        TokenKind::Keyword(Keyword::New),
        TokenKind::Keyword(Keyword::Return),
        TokenKind::Keyword(Keyword::Super),
        TokenKind::Keyword(Keyword::Switch),
        TokenKind::Keyword(Keyword::This),
        TokenKind::Keyword(Keyword::Throw),
        TokenKind::Keyword(Keyword::Try),
        TokenKind::Keyword(Keyword::TypeOf),
        TokenKind::Keyword(Keyword::Var),
        TokenKind::Keyword(Keyword::Void),
        TokenKind::Keyword(Keyword::While),
        TokenKind::Keyword(Keyword::With),
        TokenKind::Keyword(Keyword::Yield),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn check_variable_definition_tokens() {
    let s = "let a = 'hello';";
    let mut lexer = Lexer::new(s.as_bytes());

    let expected = [
        TokenKind::Keyword(Keyword::Let),
        TokenKind::identifier("a"),
        TokenKind::Punctuator(Punctuator::Assign),
        TokenKind::string_literal("hello"),
        TokenKind::Punctuator(Punctuator::Semicolon),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn check_positions() {
    let s = r#"console.log("hello world"); // Test"#;
    // --------123456789
    let mut lexer = Lexer::new(s.as_bytes());

    // The first column is 1 (not zero indexed)
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((1, 1), (1, 8)));

    // Dot Token starts on column 8
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((1, 8), (1, 9)));

    // Log Token starts on column 9
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((1, 9), (1, 12)));

    // Open parenthesis token starts on column 12
    assert_eq!(
        lexer.next().unwrap().unwrap().span(),
        span((1, 12), (1, 13))
    );

    // String token starts on column 13
    assert_eq!(
        lexer.next().unwrap().unwrap().span(),
        span((1, 13), (1, 26))
    );

    // Close parenthesis token starts on column 26.
    assert_eq!(
        lexer.next().unwrap().unwrap().span(),
        span((1, 26), (1, 27))
    );

    // Semi Colon token starts on column 35
    assert_eq!(
        lexer.next().unwrap().unwrap().span(),
        span((1, 27), (1, 28))
    );
}

#[test]
fn check_positions_codepoint() {
    let s = r#"console.log("hello world\u{{2764}}"); // Test"#;
    // --------123456789
    let mut lexer = Lexer::new(s.as_bytes());

    // The first column is 1 (not zero indexed)
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((1, 1), (1, 8)));

    // Dot Token starts on column 8
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((1, 8), (1, 9)));

    // Log Token starts on column 9
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((1, 9), (1, 12)));

    // Open parenthesis token starts on column 12
    assert_eq!(
        lexer.next().unwrap().unwrap().span(),
        span((1, 12), (1, 13))
    );

    // String token starts on column 13
    assert_eq!(
        lexer.next().unwrap().unwrap().span(),
        span((1, 13), (1, 34))
    );

    // Close parenthesis token starts on column 34
    assert_eq!(
        lexer.next().unwrap().unwrap().span(),
        span((1, 34), (1, 35))
    );

    // Semi Colon token starts on column 35
    assert_eq!(
        lexer.next().unwrap().unwrap().span(),
        span((1, 35), (1, 36))
    );
}

#[test]
fn check_line_numbers() {
    let s = "x\ny\n";

    let mut lexer = Lexer::new(s.as_bytes());

    assert_eq!(lexer.next().unwrap().unwrap().span(), span((1, 1), (1, 2)));
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((1, 2), (2, 1)));
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((2, 1), (2, 2)));
    assert_eq!(lexer.next().unwrap().unwrap().span(), span((2, 2), (3, 1)));
}

// Increment/Decrement
#[test]
fn check_decrement_advances_lexer_2_places() {
    // Here we want an example of decrementing an integer
    let mut lexer = Lexer::new(&b"let a = b--;"[..]);

    for _ in 0..4 {
        lexer.next().unwrap();
    }

    assert_eq!(
        lexer.next().unwrap().unwrap().kind(),
        &TokenKind::Punctuator(Punctuator::Dec)
    );
    // Decrementing means adding 2 characters '--', the lexer should consume it as a single token
    // and move the curser forward by 2, meaning the next token should be a semicolon

    assert_eq!(
        lexer.next().unwrap().unwrap().kind(),
        &TokenKind::Punctuator(Punctuator::Semicolon)
    );
}

#[test]
fn single_int() {
    let mut lexer = Lexer::new(&b"52"[..]);

    let expected = [TokenKind::numeric_literal(52)];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn numbers() {
    let mut lexer = Lexer::new(
        "1 2 0x34 056 7.89 42. 5e3 5e+3 5e-3 0b10 0O123 0999 1.0e1 1.0e-1 1.0E1 1E1 0.0 0.12 -32"
            .as_bytes(),
    );

    let expected = [
        TokenKind::numeric_literal(1),
        TokenKind::numeric_literal(2),
        TokenKind::numeric_literal(52),
        TokenKind::numeric_literal(46),
        TokenKind::numeric_literal(7.89),
        TokenKind::numeric_literal(42),
        TokenKind::numeric_literal(5000),
        TokenKind::numeric_literal(5000),
        TokenKind::numeric_literal(0.005),
        TokenKind::numeric_literal(2),
        TokenKind::numeric_literal(83),
        TokenKind::numeric_literal(999),
        TokenKind::numeric_literal(10),
        TokenKind::numeric_literal(0.1),
        TokenKind::numeric_literal(10),
        TokenKind::numeric_literal(10),
        TokenKind::numeric_literal(0),
        TokenKind::numeric_literal(0.12),
        TokenKind::Punctuator(Punctuator::Sub),
        TokenKind::numeric_literal(32),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn big_exp_numbers() {
    let mut lexer = Lexer::new(&b"1.0e25 1.0e36 9.0e50"[..]);

    let expected = [
        TokenKind::numeric_literal(10000000000000000000000000.0),
        TokenKind::numeric_literal(1000000000000000000000000000000000000.0),
        TokenKind::numeric_literal(900000000000000000000000000000000000000000000000000.0),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
#[ignore]
fn big_literal_numbers() {
    let mut lexer = Lexer::new(&b"10000000000000000000000000"[..]);

    let expected = [TokenKind::numeric_literal(10000000000000000000000000.0)];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn implicit_octal_edge_case() {
    let mut lexer = Lexer::new(&b"044.5 094.5"[..]);

    let expected = [
        TokenKind::numeric_literal(36),
        TokenKind::Punctuator(Punctuator::Dot),
        TokenKind::numeric_literal(5),
        TokenKind::numeric_literal(94.5),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn hexadecimal_edge_case() {
    let mut lexer = Lexer::new(&b"0xffff.ff 0xffffff"[..]);

    let expected = [
        TokenKind::numeric_literal(0xffff),
        TokenKind::Punctuator(Punctuator::Dot),
        TokenKind::identifier("ff"),
        TokenKind::numeric_literal(0x00ff_ffff),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn single_number_without_semicolon() {
    let mut lexer = Lexer::new(&b"1"[..]);
    if let Some(x) = lexer.next().unwrap() {
        assert_eq!(x.kind(), &TokenKind::numeric_literal(Numeric::Integer(1)));
    } else {
        panic!("Failed to lex 1 without semicolon");
    }
}

#[test]
fn number_followed_by_dot() {
    let mut lexer = Lexer::new(&b"1.."[..]);

    let expected = [
        TokenKind::numeric_literal(1),
        TokenKind::Punctuator(Punctuator::Dot),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn regex_literal() {
    let mut lexer = Lexer::new(&b"/(?:)/"[..]);

    let expected = [TokenKind::regular_expression_literal(
        "(?:)",
        RegExpFlags::default(),
    )];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn regex_literal_flags() {
    let mut lexer = Lexer::new(&br"/\/[^\/]*\/*/gmi"[..]);

    let mut flags = RegExpFlags::default();
    flags.insert(RegExpFlags::GLOBAL);
    flags.insert(RegExpFlags::MULTILINE);
    flags.insert(RegExpFlags::IGNORE_CASE);

    let expected = [TokenKind::regular_expression_literal(
        "\\/[^\\/]*\\/*",
        flags,
    )];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn addition_no_spaces() {
    let mut lexer = Lexer::new(&b"1+1"[..]);

    let expected = [
        TokenKind::numeric_literal(1),
        TokenKind::Punctuator(Punctuator::Add),
        TokenKind::numeric_literal(1),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn addition_no_spaces_left_side() {
    let mut lexer = Lexer::new(&b"1+ 1"[..]);

    let expected = [
        TokenKind::numeric_literal(1),
        TokenKind::Punctuator(Punctuator::Add),
        TokenKind::numeric_literal(1),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn addition_no_spaces_right_side() {
    let mut lexer = Lexer::new(&b"1 +1"[..]);

    let expected = [
        TokenKind::numeric_literal(1),
        TokenKind::Punctuator(Punctuator::Add),
        TokenKind::numeric_literal(1),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn addition_no_spaces_e_number_left_side() {
    let mut lexer = Lexer::new(&b"1e2+ 1"[..]);

    let expected = [
        TokenKind::numeric_literal(100),
        TokenKind::Punctuator(Punctuator::Add),
        TokenKind::numeric_literal(1),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn addition_no_spaces_e_number_right_side() {
    let mut lexer = Lexer::new(&b"1 +1e3"[..]);

    let expected = [
        TokenKind::numeric_literal(1),
        TokenKind::Punctuator(Punctuator::Add),
        TokenKind::numeric_literal(1000),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn addition_no_spaces_e_number() {
    let mut lexer = Lexer::new(&b"1e3+1e11"[..]);

    let expected = [
        TokenKind::numeric_literal(1000),
        TokenKind::Punctuator(Punctuator::Add),
        TokenKind::numeric_literal(100_000_000_000.0),
    ];

    expect_tokens(&mut lexer, &expected);
}

#[test]
fn take_while_pred_simple() {
    let mut cur = Cursor::new(&b"abcdefghijk"[..]);

    let mut buf: String = String::new();

    cur.take_while_pred(&mut buf, &|c| c == 'a' || c == 'b' || c == 'c')
        .unwrap();

    assert_eq!(buf, "abc");
}

#[test]
fn take_while_pred_immediate_stop() {
    let mut cur = Cursor::new(&b"abcdefghijk"[..]);

    let mut buf: String = String::new();

    cur.take_while_pred(&mut buf, &|c| c == 'd').unwrap();

    assert_eq!(buf, "");
}

#[test]
fn take_while_pred_entire_str() {
    let mut cur = Cursor::new(&b"abcdefghijk"[..]);

    let mut buf: String = String::new();

    cur.take_while_pred(&mut buf, &|c| c.is_alphabetic())
        .unwrap();

    assert_eq!(buf, "abcdefghijk");
}

#[test]
fn illegal_following_numeric_literal() {
    // Checks as per https://tc39.es/ecma262/#sec-literals-numeric-literals that a NumericLiteral cannot
    // be immediately followed by an IdentifierStart or DecimalDigit.

    // Decimal Digit
    let mut lexer = Lexer::new(&b"11.6n3"[..]);
    let err = lexer
        .next()
        .expect_err("DecimalDigit following NumericLiteral not rejected as expected");
    if let Error::Syntax(_, pos) = err {
        assert_eq!(pos, Position::new(1, 5))
    } else {
        panic!("invalid error type");
    }

    // Identifier Start
    let mut lexer = Lexer::new(&b"17.4$"[..]);
    if let Error::Syntax(_, pos) = lexer
        .next()
        .expect_err("IdentifierStart '$' following NumericLiteral not rejected as expected")
    {
        assert_eq!(pos, Position::new(1, 5));
    } else {
        panic!("invalid error type");
    }

    let mut lexer = Lexer::new(&b"17.4_"[..]);
    if let Error::Syntax(_, pos) = lexer
        .next()
        .expect_err("IdentifierStart '_' following NumericLiteral not rejected as expected")
    {
        assert_eq!(pos, Position::new(1, 5));
    } else {
        panic!("invalid error type");
    }
}

#[test]
fn codepoint_with_no_braces() {
    let mut lexer = Lexer::new(&br#""test\uD83Dtest""#[..]);
    assert!(lexer.next().is_ok());
}

#[test]
#[ignore]
fn illegal_code_point_following_numeric_literal() {
    // Checks as per https://tc39.es/ecma262/#sec-literals-numeric-literals that a NumericLiteral cannot
    // be immediately followed by an IdentifierStart where the IdentifierStart
    let mut lexer = Lexer::new(&br#"17.4\u{{2764}}"#[..]);
    assert!(
        lexer.next().is_err(),
        "IdentifierStart \\u{{2764}} following NumericLiteral not rejected as expected"
    );
}

#[test]
fn non_english_str() {
    let str = r#"'中文';"#;

    let mut lexer = Lexer::new(str.as_bytes());

    let expected = [
        TokenKind::StringLiteral("中文".into()),
        TokenKind::Punctuator(Punctuator::Semicolon),
    ];

    expect_tokens(&mut lexer, &expected);
}