#include <mbgl/text/glyph_pbf.hpp>

#include <mbgl/storage/file_source.hpp>
#include <mbgl/storage/resource.hpp>
#include <mbgl/storage/response.hpp>
#include <mbgl/text/font_stack.hpp>
#include <mbgl/text/glyph_store.hpp>
#include <mbgl/util/exception.hpp>
#include <mbgl/util/pbf.hpp>
#include <mbgl/util/string.hpp>
#include <mbgl/util/thread_context.hpp>
#include <mbgl/util/token.hpp>
#include <mbgl/util/url.hpp>

namespace {

void parseGlyphPBF(mbgl::FontStack& stack, const std::string& data) {
    mbgl::pbf glyphs_pbf(reinterpret_cast<const uint8_t *>(data.data()), data.size());

    while (glyphs_pbf.next()) {
        if (glyphs_pbf.tag == 1) { // stacks
            mbgl::pbf fontstack_pbf = glyphs_pbf.message();
            while (fontstack_pbf.next()) {
                if (fontstack_pbf.tag == 3) { // glyphs
                    mbgl::pbf glyph_pbf = fontstack_pbf.message();

                    mbgl::SDFGlyph glyph;

                    while (glyph_pbf.next()) {
                        if (glyph_pbf.tag == 1) { // id
                            glyph.id = glyph_pbf.varint();
                        } else if (glyph_pbf.tag == 2) { // bitmap
                            glyph.bitmap = glyph_pbf.string();
                        } else if (glyph_pbf.tag == 3) { // width
                            glyph.metrics.width = glyph_pbf.varint();
                        } else if (glyph_pbf.tag == 4) { // height
                            glyph.metrics.height = glyph_pbf.varint();
                        } else if (glyph_pbf.tag == 5) { // left
                            glyph.metrics.left = glyph_pbf.svarint();
                        } else if (glyph_pbf.tag == 6) { // top
                            glyph.metrics.top = glyph_pbf.svarint();
                        } else if (glyph_pbf.tag == 7) { // advance
                            glyph.metrics.advance = glyph_pbf.varint();
                        } else {
                            glyph_pbf.skip();
                        }
                    }

                    stack.insert(glyph.id, glyph);
                } else {
                    fontstack_pbf.skip();
                }
            }
        } else {
            glyphs_pbf.skip();
        }
    }
}

} // namespace

namespace mbgl {

GlyphPBF::GlyphPBF(GlyphStore* store,
                   const std::string& fontStack,
                   const GlyphRange& glyphRange,
                   GlyphStore::Observer* observer_)
    : parsed(false),
      observer(observer_) {
    FileSource* fs = util::ThreadContext::getFileSource();
    req = fs->request(Resource::glyphs(store->getURL(), fontStack, glyphRange), [this, store, fontStack, glyphRange](Response res) {
        if (res.error) {
            observer->onGlyphsError(fontStack, glyphRange, std::make_exception_ptr(std::runtime_error(res.error->message)));
            return;
        }

        if (res.notModified) {
            return;
        }

        try {
            parseGlyphPBF(**store->getFontStack(fontStack), *res.data);
        } catch (...) {
            observer->onGlyphsError(fontStack, glyphRange, std::current_exception());
            return;
        }

        parsed = true;
        observer->onGlyphsLoaded(fontStack, glyphRange);
    });
}

GlyphPBF::~GlyphPBF() = default;

} // namespace mbgl