// Copyright 2019 Google LLC.

#ifndef FontIterator_DEFINED

#define FontIterator_DEFINED

#include "include/core/SkSpan.h"

#include "include/core/SkString.h"

#include "include/core/SkTypes.h"

#include "modules/skparagraph/include/TextStyle.h"

#include "modules/skshaper/include/SkShaper.h"

namespace skia {

namespace textlayout {

class LangIterator final : public SkShaper::LanguageRunIterator {

public:

    LangIterator(SkSpan<const char> utf8, SkSpan<Block> styles, const TextStyle& defaultStyle)

            : fText(utf8)

            , fTextStyles(styles)

            , fCurrentChar(utf8.begin())

            , fCurrentStyle(fTextStyles.begin())

            , fCurrentLocale(defaultStyle.getLocale()) {}

    void consume() override {

        SkASSERT(fCurrentChar < fText.end());

        if (fCurrentStyle == fTextStyles.end()) {

            fCurrentChar = fText.end();

            return;

        }

        fCurrentChar = fText.begin() + fCurrentStyle->fRange.end;

        fCurrentLocale = fCurrentStyle->fStyle.getLocale();

        while (++fCurrentStyle != fTextStyles.end() && !fCurrentStyle->fStyle.isPlaceholder()) {

            if (fCurrentStyle->fStyle.getLocale() != fCurrentLocale) {

                break;

            }

            fCurrentChar = fText.begin() + fCurrentStyle->fRange.end;

        }

    }

    size_t endOfCurrentRun() const override { return fCurrentChar - fText.begin(); }

    bool atEnd() const override { return fCurrentChar >= fText.end(); }

    const char* currentLanguage() const override { return fCurrentLocale.c_str(); }

private:

    SkSpan<const char> fText;

    SkSpan<Block> fTextStyles;

    const char* fCurrentChar;

    Block* fCurrentStyle;

    SkString fCurrentLocale;

};

}  // namespace textlayout

}  // namespace skia

#endif  // FontIterator_DEFINED