#include <qpdf/QPDF.hh>
#include <qpdf/QPDFWriter.hh>
#include <qpdf/QPDFObjectHandle.hh>
#include <qpdf/QUtil.hh>
#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <assert.h>

// Run "test_large_file write small a.pdf" to get a PDF file that you
// can look at in a reader.

// This program reads and writes specially crafted files for testing
// large file support.  In write mode, write a file of npages pages
// where each page contains unique text and a unique image.  The image
// is a binary representation of the page number.  The image contains
// horizontal stripes with light stripes representing 1, dark stripes
// representing 0, and the high bit on top.  In read mode, read the
// file back checking to make sure all the image data and page
// contents are as expected.

// Running this is small mode produces a small file that is easy to
// look at in any viewer.  Since there is no question about proper
// functionality for small files, writing and reading the small file
// allows the qpdf library to test this test program.  Writing and
// reading the large file then allows us to verify large file support
// with confidence.

static char const* whoami = 0;

// Height should be a multiple of 10
static int const nstripes = 10;
static int const stripesize_large = 500;
static int const stripesize_small = 5;
static int const npages = 200;

// initialized in main
int stripesize = 0;
int width = 0;
int height = 0;
static unsigned char* buf = 0;

static inline unsigned char get_pixel_color(int n, int row)
{
    return (n & (1 << (nstripes - 1 - row))) ? '\xc0' : '\x40';
}

class ImageChecker: public Pipeline
{
  public:
    ImageChecker(int n);
    virtual ~ImageChecker();
    virtual void write(unsigned char* data, size_t len);
    virtual void finish();

  private:
    int n;
    size_t offset;
    bool okay;
};

ImageChecker::ImageChecker(int n) :
    Pipeline("image checker", 0),
    n(n),
    offset(0),
    okay(true)
{
}

ImageChecker::~ImageChecker()
{
}

void
ImageChecker::write(unsigned char* data, size_t len)
{
    for (size_t i = 0; i < len; ++i)
    {
        int y = (this->offset + i) / width / stripesize;
        unsigned char color = get_pixel_color(n, y);
        if (data[i] != color)
        {
            okay = false;
        }
    }
    this->offset += len;
}

void
ImageChecker::finish()
{
    if (! okay)
    {
        std::cout << "errors found checking image data for page " << n
                  << std::endl;
    }
}

class ImageProvider: public QPDFObjectHandle::StreamDataProvider
{
  public:
    ImageProvider(int n);
    virtual ~ImageProvider();
    virtual void provideStreamData(int objid, int generation,
				   Pipeline* pipeline);
    size_t getLength() const;

  private:
    int n;
};

ImageProvider::ImageProvider(int n) :
    n(n)
{
}

ImageProvider::~ImageProvider()
{
}

void
ImageProvider::provideStreamData(int objid, int generation,
                                 Pipeline* pipeline)
{
    if (buf == 0)
    {
        buf = new unsigned char[width * stripesize];
    }
    std::cout << "page " << n << " of " << npages << std::endl;
    for (int y = 0; y < nstripes; ++y)
    {
        unsigned char color = get_pixel_color(n, y);
        memset(buf, (int) color, width * stripesize);
        pipeline->write(buf, width * stripesize);
    }
    pipeline->finish();
}

size_t
ImageProvider::getLength() const
{
    return width * height;
}

void usage()
{
    std::cerr << "Usage: " << whoami << " {read|write} {large|small} outfile"
              << std::endl;
    exit(2);
}

static void set_parameters(bool large)
{
    stripesize = large ? stripesize_large : stripesize_small;
    height = nstripes * stripesize;
    width = height;
}

std::string generate_page_contents(int pageno)
{
    std::string contents =
        "BT /F1 24 Tf 72 720 Td (page " +  QUtil::int_to_string(pageno) +
        ") Tj ET\n"
        "q 468 0 0 468 72 72 cm /Im1 Do Q\n";
    return contents;
}

static QPDFObjectHandle create_page_contents(QPDF& pdf, int pageno)
{
    std::string contents = generate_page_contents(pageno);
    PointerHolder<Buffer> b = new Buffer(contents.length());
    unsigned char* bp = b->getBuffer();
    memcpy(bp, (char*)contents.c_str(), contents.length());
    return QPDFObjectHandle::newStream(&pdf, b);
}

QPDFObjectHandle newName(std::string const& name)
{
    return QPDFObjectHandle::newName(name);
}

QPDFObjectHandle newInteger(int val)
{
    return QPDFObjectHandle::newInteger(val);
}

static void create_pdf(char const* filename)
{
    QPDF pdf;

    pdf.emptyPDF();

    QPDFObjectHandle font = pdf.makeIndirectObject(
        QPDFObjectHandle::newDictionary());
    font.replaceKey("/Type", newName("/Font"));
    font.replaceKey("/Subtype", newName("/Type1"));
    font.replaceKey("/Name", newName("/F1"));
    font.replaceKey("/BaseFont", newName("/Helvetica"));
    font.replaceKey("/Encoding", newName("/WinAnsiEncoding"));

    QPDFObjectHandle procset =
        pdf.makeIndirectObject(QPDFObjectHandle::newArray());
    procset.appendItem(newName("/PDF"));
    procset.appendItem(newName("/Text"));
    procset.appendItem(newName("/ImageC"));

    QPDFObjectHandle rfont = QPDFObjectHandle::newDictionary();
    rfont.replaceKey("/F1", font);

    QPDFObjectHandle mediabox = QPDFObjectHandle::newArray();
    mediabox.appendItem(newInteger(0));
    mediabox.appendItem(newInteger(0));
    mediabox.appendItem(newInteger(612));
    mediabox.appendItem(newInteger(792));

    for (int pageno = 1; pageno <= npages; ++pageno)
    {
        QPDFObjectHandle image = QPDFObjectHandle::newStream(&pdf);
        QPDFObjectHandle image_dict = image.getDict();
        image_dict.replaceKey("/Type", newName("/XObject"));
        image_dict.replaceKey("/Subtype", newName("/Image"));
        image_dict.replaceKey("/ColorSpace", newName("/DeviceGray"));
        image_dict.replaceKey("/BitsPerComponent", newInteger(8));
        image_dict.replaceKey("/Width", newInteger(width));
        image_dict.replaceKey("/Height", newInteger(height));
        ImageProvider* p = new ImageProvider(pageno);
        PointerHolder<QPDFObjectHandle::StreamDataProvider> provider(p);
        image.replaceStreamData(provider,
                                QPDFObjectHandle::newNull(),
                                QPDFObjectHandle::newNull(),
                                p->getLength());

        QPDFObjectHandle xobject = QPDFObjectHandle::newDictionary();
        xobject.replaceKey("/Im1", image);

        QPDFObjectHandle resources = QPDFObjectHandle::newDictionary();
        resources.replaceKey("/ProcSet", procset);
        resources.replaceKey("/Font", rfont);
        resources.replaceKey("/XObject", xobject);

        QPDFObjectHandle contents = create_page_contents(pdf, pageno);

        QPDFObjectHandle page = pdf.makeIndirectObject(
            QPDFObjectHandle::newDictionary());
        page.replaceKey("/Type", newName("/Page"));
        page.replaceKey("/MediaBox", mediabox);
        page.replaceKey("/Contents", contents);
        page.replaceKey("/Resources", resources);

        pdf.addPage(page, false);
    }

    QPDFWriter w(pdf, filename);
    w.setStaticID(true);    // for testing only
    w.setStreamDataMode(qpdf_s_preserve);
    w.setObjectStreamMode(qpdf_o_disable);
    w.write();
}

static void check_page_contents(int pageno, QPDFObjectHandle page)
{
    PointerHolder<Buffer> buf =
        page.getKey("/Contents").getStreamData();
    std::string actual_contents =
        std::string((char *)(buf->getBuffer()), buf->getSize());
    std::string expected_contents = generate_page_contents(pageno);
    if (expected_contents != actual_contents)
    {
        std::cout << "page contents wrong for page " << pageno << std::endl
                  << "ACTUAL: " << actual_contents
                  << "EXPECTED: " << expected_contents
                  << "----\n";
    }
}

static void check_image(int pageno, QPDFObjectHandle page)
{
    QPDFObjectHandle image =
        page.getKey("/Resources").getKey("/XObject").getKey("/Im1");
    ImageChecker ic(pageno);
    image.pipeStreamData(&ic, true, false, false);
}

static void check_pdf(char const* filename)
{
    QPDF pdf;
    pdf.processFile(filename);
    std::vector<QPDFObjectHandle> const& pages = pdf.getAllPages();
    assert(pages.size() == (size_t)npages);
    for (int i = 0; i < npages; ++i)
    {
        int pageno = i + 1;
        std::cout << "page " << pageno << " of " << npages << std::endl;
        check_page_contents(pageno, pages[i]);
        check_image(pageno, pages[i]);
    }
}

int main(int argc, char* argv[])
{
    whoami = QUtil::getWhoami(argv[0]);
    QUtil::setLineBuf(stdout);

    // For libtool's sake....
    if (strncmp(whoami, "lt-", 3) == 0)
    {
	whoami += 3;
    }
    if (argc != 4)
    {
	usage();
    }
    char const* operation = argv[1];
    char const* size = argv[2];
    char const* filename = argv[3];

    bool op_write = false;
    bool size_large = false;

    if (strcmp(operation, "write") == 0)
    {
        op_write = true;
    }
    else if (strcmp(operation, "read") == 0)
    {
        op_write = false;
    }
    else
    {
        usage();
    }

    if (strcmp(size, "large") == 0)
    {
        size_large = true;
    }
    else if (strcmp(size, "small") == 0)
    {
        size_large = false;
    }
    else
    {
        usage();
    }

    set_parameters(size_large);

    try
    {
        if (op_write)
        {
            create_pdf(filename);
        }
        else
        {
            check_pdf(filename);
        }
    }
    catch (std::exception& e)
    {
	std::cerr << e.what() << std::endl;
	exit(2);
    }

    delete [] buf;

    return 0;
}