#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <string>

#include <msdfgen.h>
#include <ext/import-font.h>

static unsigned char clamp_channel(float v) {
    if (v <= 0.0f) return 0;
    if (v >= 1.0f) return 255;
    return static_cast<unsigned char>(std::lround(v * 255.0f));
}

int main(int argc, char **argv) {
    if (argc < 3) {
        std::fprintf(stderr, "Usage: %s <font-file> <codepoint>\n", argv[0]);
        return 1;
    }
    const char *fontPath = argv[1];
    unsigned codepoint = std::strtoul(argv[2], nullptr, 0);
    auto *ft = msdfgen::initializeFreetype();
    if (!ft) return 1;
    auto *font = msdfgen::loadFont(ft, fontPath);
    if (!font) return 1;
    msdfgen::Shape shape;
    double advance = 0.0;
    if (!msdfgen::loadGlyph(shape, font, msdfgen::GlyphIndex(codepoint), msdfgen::FONT_SCALING_EM_NORMALIZED, &advance)) {
        std::fprintf(stderr, "Failed to load glyph %u\n", codepoint);
        return 1;
    }
    shape.normalize();
    msdfgen::edgeColoringSimple(shape, 3.0);
    auto bounds = shape.getBounds();

    double emScale = 48.0;
    double pxRange = 4.0;
    int bmp_w = std::max(1, (int)std::ceil((bounds.r - bounds.l) * emScale + 2.0 * pxRange));
    int bmp_h = std::max(1, (int)std::ceil((bounds.t - bounds.b) * emScale + 2.0 * pxRange));

    msdfgen::Bitmap<float, 3> bitmap(bmp_w, bmp_h);
    msdfgen::Vector2 scale(emScale, emScale);
    msdfgen::Vector2 translate(-bounds.l * emScale + pxRange, -bounds.b * emScale + pxRange);
    msdfgen::generateMSDF(bitmap, shape, pxRange, scale, translate);

    std::vector<unsigned char> buffer(static_cast<size_t>(bmp_w) * bmp_h * 4);
    for (int y = 0; y < bmp_h; ++y) {
        int dst_y = bmp_h - 1 - y;
        for (int x = 0; x < bmp_w; ++x) {
            const float *px = bitmap(x, y);
            size_t idx = (static_cast<size_t>(dst_y) * bmp_w + x) * 4;
            buffer[idx + 0] = clamp_channel(px[0]);
            buffer[idx + 1] = clamp_channel(px[1]);
            buffer[idx + 2] = clamp_channel(px[2]);
            buffer[idx + 3] = 255;
        }
    }

    int minX = bmp_w, minY = bmp_h, maxX = -1, maxY = -1;
    for (int y = 0; y < bmp_h; ++y) {
        for (int x = 0; x < bmp_w; ++x) {
            size_t idx = (static_cast<size_t>(y) * bmp_w + x) * 4;
            unsigned char r = buffer[idx];
            unsigned char g = buffer[idx + 1];
            unsigned char b = buffer[idx + 2];
            bool interesting = !(r == 0 && g == 0 && b == 0) && !(r == 255 && g == 255 && b == 255);
            if (interesting) {
                if (x < minX) minX = x;
                if (x > maxX) maxX = x;
                if (y < minY) minY = y;
                if (y > maxY) maxY = y;
            }
        }
    }

    std::printf("bmp %dx%d\n", bmp_w, bmp_h);
    if (maxX >= minX && maxY >= minY) {
        std::printf("interesting bbox: x=[%d,%d] y=[%d,%d]\n", minX, maxX, minY, maxY);
    }

    msdfgen::destroyFont(font);
    msdfgen::deinitializeFreetype(ft);
    return 0;
}