#include <windows.h>

#include "gear.h"
#include "i_PDF.h"

// This function returns a new font to use for the text element.
HIG_PDE_FONT CreateNewFont( )
{
    // Declare variables.
    AT_PDE_FONTATTRS fontAttrs;
    HIG_PDE_FONT hFont = NULL;
    HIG_PDF_SYSFONT hSysFont = NULL;

    // Initialize font attributes.
    memset(&fontAttrs, 0, sizeof(fontAttrs));
    // Set font name attribute.
    IG_PDF_atom_from_string("Times-Roman", &(fontAttrs.name));
    // Set font type attribute.
    IG_PDF_atom_from_string("Type1", &(fontAttrs.type));

    // Create from sysfont.
    IG_PDF_sysfont_find(&fontAttrs, 0, &hSysFont);
    IG_PDE_font_create_from_sysfont(hSysFont, 0, IG_PDF_ATOM_NULL, NULL, &hFont);
    IG_PDF_sysfont_release(hSysFont);

    return hFont;
}

// This function will add a text element into the content of the PDF document.
void AddTextToFirstPDFPage( HMIGEAR document)
{
    // Declare variables.
    HIGEAR page = NULL;
    HIG_PDF_PAGE hPDFPage = NULL;
    HIG_PDE_CONTENT hContent = NULL;
    HIG_PDE_FONT hFont = NULL;
    HIG_PDF_ATOM hCSName = IG_PDF_ATOM_NULL;
    HIG_PDE_COLORSPACE hColorSpace = NULL;
    AT_PDE_GRAPHICSTATE graphicState;
    HIG_PDE_TEXT hText = NULL;
    AT_PDF_FIXEDMATRIX textMatrix;
    AT_PDF_FIXEDRECT cropBox;
    LPSTR textToAdd;
    int textLength = 0;
    LONG horizontalCenter, verticalCenter, textWidthEM, scaledTextWidth,
        textXPosition, textYPosition = 0;
    SHORT fontWidthScale, fontHeightScale = 0;

    // Get first page.
    IG_mpi_page_get(document, 0, &page);

    // Obtain PDF page.
    IG_vector_data_get(page, (LPVOID*)&hPDFPage);

    // Get page content.
    IG_PDF_page_get_content(hPDFPage, &hContent);

    // Create a font to use with the text element.
    hFont = CreateNewFont();

    // Set the color space to DeviceRGB.
    IG_PDF_atom_from_string("DeviceRGB", &hCSName);
    IG_PDE_colorspace_create(hCSName, NULL, &hColorSpace);

    // Set the attributes for the graphic state.
    memset(&graphicState, 0, sizeof(graphicState));
    graphicState.strokeColorSpec.space = graphicState.fillColorSpec.space = hColorSpace;

    // Create a blue text (for example).
    // Note: Color values are expressed as real numbers.
        // Set R componet.
    graphicState.fillColorSpec.value.color[0] = 0;
    // Set G componet.
    graphicState.fillColorSpec.value.color[1] = 0;
    // Set B componet.
    graphicState.fillColorSpec.value.color[2] = AM_PDF_DOUBLE_TO_FIXED(255./255);

    graphicState.miterLimit = IG_PDF_FIXED_TEN;
    graphicState.flatness = IG_PDF_FIXED_ONE;
    graphicState.lineWidth = IG_PDF_FIXED_ONE;

    // Create a string of text.
    textToAdd = "This is the string of text that will be added";

    // Set the length of the text.
    textLength = strlen(textToAdd);

    // Get page box.
    IG_PDF_page_get_crop_box(hPDFPage, &cropBox);

    // Calculate the center of the page.
    horizontalCenter = (cropBox.right - cropBox.left)/2;
    verticalCenter = (cropBox.top - cropBox.bottom)/2;

    // Get the width of the text in EM space.
    // Note: One EM in a 16-point typeface is 16 points.
    IG_PDE_font_sum_widths(hFont, (LPBYTE)textToAdd, textLength, &textWidthEM);
        
    fontWidthScale = 20;
    fontHeightScale = 20;

    // Get the width of the text considering font size.
    // Note: Convert from thousandths of a point to points and adjusts by the width scale factor.
    scaledTextWidth = (textWidthEM/1000) * fontWidthScale;

    // Set coordinates to center the text.
    textXPosition = horizontalCenter - AM_PDF_LONG_TO_FIXED(scaledTextWidth/ 2);
    textYPosition = verticalCenter;

    // Create a matrix to draw text with font size 20pt at the center of the page.
    // Note: The text matrix is a 3x3 affine transform matrix, depicted in its
    // abbreviated form: [ a b c d h v ]
    // * Set matrix values a and d to the font size in pt.
    // * Set matrix values h and v to move glyphs from user space origin to a place on the page.
    memset(&textMatrix, 0, sizeof(textMatrix));
    textMatrix.a = AM_PDF_SHORT_TO_FIXED(fontWidthScale);
    textMatrix.d = AM_PDF_SHORT_TO_FIXED(fontHeightScale);
    textMatrix.h = textXPosition;
    textMatrix.v = textYPosition;

    // Create new text run.
    IG_PDE_text_create(&hText);

    // Add the textToAdd into the element using the settings from above.
    IG_PDE_text_add(hText, IG_PDE_TEXT_RUN, 0, (LPBYTE)textToAdd, textLength, hFont,
            &graphicState, NULL, &textMatrix, NULL);
    // Add the text element into the content.
    IG_PDE_content_add_element(hContent, IG_PDE_AFTER_LAST, hText);

    // Set the page's PDE content back into the page object.
    IG_PDF_page_set_content(hPDFPage);

    // Release the objects created.
    IG_PDE_element_release(hText);
    IG_PDE_colorspace_release(hColorSpace);
    IG_PDF_page_release_content( hPDFPage );
}