#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <qrencode.h>
#include <magick/api.h>

#define DEFAULT_TEXT "http:/""/upsuper.org/"

int main(int argc, char **argv) {
    int i, j;
    int scale;
    QRecLevel level;
    char *text;

    // 设置默认参数
    scale = 8;
    level = QR_ECLEVEL_Q;
    text = (char *)malloc(strlen(DEFAULT_TEXT) + 1);
    strcpy(text, DEFAULT_TEXT);

    // 读取参数
    const char *orig;
    char *query_string;
    char *p;
    int len;
    orig = getenv("QUERY_STRING");
    len = strlen(orig);
    query_string = (char *)malloc(len + 2);
    *query_string = '&';
    strcpy(query_string + 1, orig);
    for (p = query_string; *p; ++p) {
        if (*p != '&')
            continue;
        if (strncasecmp(p + 1, "scale=", 6) == 0) {
            scale = atol(p + 7);
        } else if (strncasecmp(p + 1, "text=", 5) == 0) {
            char *p_last, *p_src, *p_dest;
            for (p_last = p + 6; *p_last && *p_last != '&'; ++p_last);
            text = (char *)realloc((void *)text, p_last - p - 6 + 1);
            for (p_src = p + 6, p_dest = text;
                    p_src < p_last;
                    ++p_src, ++p_dest) {
                if (*p_src == '+') {
                    *p_dest = ' ';
                } else if (*p_src == '%') {
                    int code;
                    if (sscanf(p_src + 1, "%2x", &code) != 1)
                        code = '?';
                    *p_dest = code;
                    p_src += 2;
                } else {
                    *p_dest = *p_src;
                }
            }
            *p_dest = '\0';
        } else if (strncasecmp(p + 1, "level=", 6) == 0) {
            switch (*(p + 7)) {
                case 'l': case 'L': level = QR_ECLEVEL_L; break;
                case 'm': case 'M': level = QR_ECLEVEL_M; break;
                case 'q': case 'Q': level = QR_ECLEVEL_Q; break;
                case 'h': case 'H': level = QR_ECLEVEL_H; break;
            }
        }
    }
    
    // 生成 QR code
    QRcode *qrcode;
    int width;
    qrcode = QRcode_encodeString8bit(text, 0, level);
    width = qrcode->width;
    // 初始化 Image Magick
    ImageInfo *image_info;
    ExceptionInfo exception;
    InitializeMagick(*argv);
    GetExceptionInfo(&exception);
    // 初始化图片
    Image *image, *resized_image;
    image_info = CloneImageInfo((ImageInfo *)NULL);
    image = AllocateImage(image_info);
    image->columns = image->rows = width;
    // 生成图片
    PixelPacket *pixel_packet;
    int t_bit;
    for (i = 0; i < width; ++i) {
        pixel_packet = SetImagePixels(image, 0, i, width, 1);
        if (! pixel_packet)
            break;
        for (j = 0; j < width; ++j, ++pixel_packet) {
            t_bit = ! (qrcode->data[i * width + j] & 1);
            pixel_packet->red   = MaxRGB * t_bit;
            pixel_packet->green = MaxRGB * t_bit;
            pixel_packet->blue  = MaxRGB * t_bit;
        }
        if (! SyncImagePixels(image))
            break;
    }
    QRcode_free(qrcode);
    // 处理图片
    resized_image = ScaleImage(image,
            width * scale, width * scale, &exception);
    DestroyImage(image);
    CompressImageColormap(resized_image);
    // 输出图片
    puts("Content-Type: image/png");
    puts("");
    strcpy(resized_image->filename, "png:-");
    WriteImage(image_info, resized_image);
    // 清理
    DestroyImage(resized_image);
    DestroyImageInfo(image_info);
    DestroyExceptionInfo(&exception);
    DestroyMagick();
    
    return 0;
}