module.exports = grammar({
    name: 'stonescript',

    rules: {
        source_file: $ => repeat($._statement),

        _statement: $ => prec.right(seq(
            choice(
                // Comments first
                $.comment,
                $.block_comment,
                // Keyword-based statements (must come before generic command)
                $.variable_declaration,      // 'var'
                $.function_declaration,      // 'func'
                $.for_loop,                  // 'for'
                $.return_statement,          // 'return'
                $.break_statement,           // 'break'
                $.continue_statement,        // 'continue'
                $.import_statement,          // 'import'
                // Control flow
                $.conditional,               // '?'
                $.else_clause,               // ':'
                // Commands (higher precedence!)
                prec.dynamic(1, $.command),
                $.print_command,
                // Fallback
                $.expression_statement
            ),
            optional($._newline)
        )),

        // Comments
        comment: $ => token(seq('//', /.*/)),

        block_comment: $ => token(seq(
            '/*',
            /[^*]*\*+(?:[^/*][^*]*\*+)*/,
            '/'
        )),

        // Variable declaration
        variable_declaration: $ => seq(
            'var',
            field('name', $.identifier),
            optional(seq('=', field('value', $._expression)))
        ),

        // Function declaration
        function_declaration: $ => seq(
            'func',
            field('name', $.identifier),
            '(',
            optional($.parameter_list),
            ')',
            $.block
        ),

        parameter_list: $ => seq(
            $.identifier,
            repeat(seq(',', $.identifier))
        ),

        // Loops
        for_loop: $ => choice(
            seq(
                'for',
                $.identifier,
                '=',
                $._expression,
                '..',
                $._expression,
                $.block
            ),
            seq(
                'for',
                $.identifier,
                ':',
                $._expression,
                $.block
            )
        ),

        // Import
        import_statement: $ => seq(
            'import',
            $.module_path
        ),

        new_statement: $ => seq(
            'new',
            $.module_path
        ),

        module_path: $ => /[a-zA-Z_][a-zA-Z0-9_\\/]*/,

        // Control flow
        return_statement: $ => prec.right(seq(
            'return',
            optional($._expression)
        )),

        break_statement: $ => 'break',

        continue_statement: $ => 'continue',

        // Conditionals
        conditional: $ => seq(
            '?',
            $._expression,
            $.block
        ),

        else_clause: $ => choice(
            seq(':?', $._expression, $.block),
            seq(':', $.block)
        ),

        block: $ => seq(
            $._indent,
            repeat1($._statement),
            $._dedent
        ),

        // Commands - Generic structure to match tests
        // Must have at least one argument to distinguish from simple identifier expressions  
        command: $ => prec.dynamic(1, prec.right(seq(
            $.identifier,
            repeat1($._command_arg)
        ))),

        _command_arg: $ => choice(
            $.identifier,
            $.number,
            $.string,
            $.star_level,
            $.enchantment_level
        ),

        star_level: $ => seq('*', $.number),

        enchantment_level: $ => seq('+', $.number),

        print_command: $ => prec.right(seq(
            choice('>', '>o', '>h', '>`', '>c', '>f'),
            optional($.print_args)
        )),

        // Print specific helpers
        print_args: $ => sep1(',', $.print_argument),

        print_argument: $ => prec.left(repeat1(choice(
            $.interpolation,
            $.string,
            // $.ascii_string,
            $.color_code,
            $.print_text
        ))),

        print_text: $ => /[^,@\r\n"]+/,

        interpolation: $ => seq(
            '@',
            $._expression,
            '@'
        ),

        color_code: $ => /#[a-zA-Z0-9]+/,

        // Expressions
        expression_statement: $ => $._expression,

        _expression: $ => choice(
            $.identifier,
            $.number,
            $.float,
            $.string,
            $.boolean,
            $.null,
            $.array,
            $.member_expression,
            $.call_expression,
            $.index_expression,
            $.unary_expression,
            $.binary_expression,
            $.update_expression,
            $.assignment_expression,
            $.parenthesized_expression,
            $.new_statement,
            $.ascii_string,
            $.color_code
        ),

        member_expression: $ => prec.left(15, seq(
            field('object', $._expression),
            '.',
            field('property', $.identifier)
        )),

        call_expression: $ => prec.left(14, seq(
            field('function', $._expression),
            '(',
            optional($.argument_list),
            ')'
        )),

        argument_list: $ => sep1($.comma_sep, $._expression),

        comma_sep: $ => ',',

        index_expression: $ => prec.left(13, seq(
            $._expression,
            choice('[', '［'),
            $._expression,
            choice(']', '］')
        )),

        unary_expression: $ => prec.right(12, seq(
            choice('!', '-'),
            $._expression
        )),

        // Binary operators with proper precedence
        binary_expression: $ => choice(
            prec.left(4, seq($._expression, '|', $._expression)),
            prec.left(5, seq($._expression, '&', $._expression)),
            prec.left(7, seq($._expression, '!', $._expression)),
            prec.left(7, seq($._expression, '=', $._expression)),
            prec.left(8, seq($._expression, '<', $._expression)),
            prec.left(8, seq($._expression, '>', $._expression)),
            prec.left(8, seq($._expression, '<=', $._expression)),
            prec.left(8, seq($._expression, '>=', $._expression)),
            prec.left(9, seq($._expression, '+', $._expression)),
            prec.left(9, seq($._expression, '-', $._expression)),
            prec.left(10, seq($._expression, '*', $._expression)),
            prec.left(10, seq($._expression, '/', $._expression)),
            prec.left(11, seq($._expression, '%', $._expression))
        ),

        update_expression: $ => choice(
            prec.left(12, seq($._expression, choice('++', '--'))),
            prec.right(12, seq(choice('++', '--'), $._expression))
        ),

        assignment_expression: $ => prec.right(2, seq(
            $._expression,
            choice('=', '+=', '-=', '*=', '/='),
            $._expression
        )),

        parenthesized_expression: $ => seq(
            '(',
            $._expression,
            ')'
        ),

        // Arrays
        array: $ => seq(
            choice('[', '［'),
            repeat($._newline),
            optional(seq(
                $.array_elements,
                repeat($._newline)
            )),
            choice(']', '］')
        ),

        array_elements: $ => seq(
            $._expression,
            repeat(seq(
                ',',
                repeat($._newline),
                $._expression
            )),
            optional(',')
        ),

        // Primitives
        identifier: $ => /[a-zA-Z_][a-zA-Z0-9_]*/,

        number: $ => /\d+/,

        float: $ => /\d+\.\d+/,

        string: $ => choice(
            seq('"', repeat(choice(/[^"\\]/, /\\./)), '"'),
            seq('＂', repeat(choice(/[^＂\\]/, /\\./)), '＂')
        ),

        boolean: $ => choice('true', 'false'),

        null: $ => 'null',

        ascii_string: $ => choice(
            seq('ascii', $.ascii_content, 'asciiend'),
            seq(choice('[', '［'), 'ascii', $.ascii_content, 'asciiend', choice(']', '］'))
        )
    },

    extras: $ => [
        /[ \t\r\f]/,
        /\r?\n[ \t]*\^/,
        $.comment,
        $.block_comment
    ],

    externals: $ => [
        $._newline,
        $._indent,
        $._dedent,
        $.ascii_content
    ],

    word: $ => $.identifier,

    conflicts: $ => [
        [$.identifier, $.string],
        [$._expression],
        [$.command],
        [$._statement, $._expression],  // new_statement can be both
        [$.binary_expression, $.assignment_expression],  // = operator ambiguity
        [$.command, $._expression], // * operator ambiguity
        [$.array_elements],
        [$.ascii_string]
    ]
});

// Helper to create comma-separated lists
function sep1(separator, rule) {
    return seq(rule, repeat(seq(separator, rule)));
}