#pragma once

#include <cstdint>

#include "commons/commons_byteparser.h"
#include "commons/commons_hex.h"
#include "commons/commons_macros.h"
#include "commons/commons_span_def.h"
#include "commons/commons_stringparser.h"

INLINE auto IsHexDigit(uint8_t ch) -> bool
{
    if (ch >= '0' && ch <= '9')
        return true;
    if (ch >= 'a' && ch <= 'f')
        return true;
    if (ch >= 'A' && ch <= 'F')
        return true;
    return false;
}

INLINE auto IsIdentifierStart(uint8_t ch) -> bool
{
    return IsAlpha(ch) || ch == '_';
}

INLINE auto IsIdentifierCont(uint8_t ch) -> bool
{
    return IsAlpha(ch) || IsNumber(ch) || ch == '_';
}

INLINE void TokenParser_SkipLineWhitespace(byte_parser& self)
{
    while (ByteParser_HasNext(self)) {
        const uint8_t ch = ByteParser_Peek(self);
        if (ch != ' ' && ch != '\t')
            break;
        ByteParser_Advance(self);
    }
}

INLINE auto TokenParser_SkipLineComment(byte_parser& self, uint8_t commentChar = '#') -> bool
{
    if (!ByteParser_HasNext(self) || ByteParser_Peek(self) != commentChar)
        return false;

    ByteParser_NextLine(self);
    return true;
}

[[nodiscard]]
INLINE auto TokenParser_ParseIdentifier(byte_parser& self) -> byteview
{
    ASSERT(ByteParser_HasNext(self) && IsIdentifierStart(ByteParser_Peek(self)));

    const uint8_t* start = self.at;
    ByteParser_Advance(self);
    while (ByteParser_HasNext(self) && IsIdentifierCont(ByteParser_Peek(self)))
        ByteParser_Advance(self);

    return byteview { start, (uint64_t)(self.at - start) };
}

[[nodiscard]]
INLINE auto TokenParser_ParseHexU64(byte_parser& self) -> uint64_t
{
    (void)(ByteParser_StartsWithAdvance(self, "0x"_s) || ByteParser_StartsWithAdvance(self, "0X"_s));

    ASSERT(ByteParser_HasNext(self) && IsHexDigit(ByteParser_Peek(self)));

    uint64_t value = 0;
    uint32_t digits = 0;
    while (ByteParser_HasNext(self) && IsHexDigit(ByteParser_Peek(self))) {
        ASSERT(digits < 16);
        value = (value << 4) | ParseHexChar(ByteParser_Read(self));
        ++digits;
    }
    return value;
}