/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include <sal/types.h>
#include <math.h>
#include <string.h>

#define LOK_USE_UNSTABLE_API
#include <LibreOfficeKit/LibreOfficeKit.h>

#include <LibreOfficeKit/LibreOfficeKitGtk.h>

#ifndef G_SOURCE_REMOVE
#define G_SOURCE_REMOVE FALSE
#endif

static void lok_docview_class_init( LOKDocViewClass* pClass );
static void lok_docview_init( LOKDocView* pDocView );

// We specifically need to destroy the document when closing in order to ensure
// that lock files etc. are cleaned up.
void lcl_onDestroy( LOKDocView* pDocView, gpointer pData )
{
    (void) pData;
    if ( pDocView->pDocument )
        pDocView->pDocument->pClass->destroy( pDocView->pDocument );
    pDocView->pDocument = NULL;
}

SAL_DLLPUBLIC_EXPORT guint lok_docview_get_type()
{
    static guint lok_docview_type = 0;

    if (!lok_docview_type)
    {
        GtkTypeInfo lok_docview_info =
        {
            "LokDocView",
            sizeof( LOKDocView ),
            sizeof( LOKDocViewClass ),
            (GtkClassInitFunc) lok_docview_class_init,
            (GtkObjectInitFunc) lok_docview_init,
            NULL,
            NULL,
            (GtkClassInitFunc) NULL
        };

        lok_docview_type = gtk_type_unique( gtk_scrolled_window_get_type(), &lok_docview_info );
    }
    return lok_docview_type;
}

static void lok_docview_class_init( LOKDocViewClass* pClass )
{
    (void)pClass;
}

static void lok_docview_init( LOKDocView* pDocView )
{
    // Gtk ScrolledWindow is apparently not fully initialised yet, we specifically
    // have to set the [hv]adjustment to prevent GTK assertions from firing, see
    // https://bugzilla.gnome.org/show_bug.cgi?id=438114 for more info.
    gtk_scrolled_window_set_hadjustment( GTK_SCROLLED_WINDOW( pDocView ), NULL );
    gtk_scrolled_window_set_vadjustment( GTK_SCROLLED_WINDOW( pDocView ), NULL );

    pDocView->pEventBox = gtk_event_box_new();
    gtk_scrolled_window_add_with_viewport( GTK_SCROLLED_WINDOW(pDocView),
                                           pDocView->pEventBox );

    // Allow reacting to button press events.
    gtk_widget_set_events(pDocView->pEventBox, GDK_BUTTON_PRESS_MASK);

    gtk_widget_show( pDocView->pEventBox );

    pDocView->pTable = 0;
    pDocView->pCanvas = 0;

    // TODO: figure out a clever view of getting paths set up.
    pDocView->pOffice = 0;
    pDocView->pDocument = 0;

    pDocView->fZoom = 1;
    pDocView->m_bEdit = FALSE;

    gtk_signal_connect( GTK_OBJECT(pDocView), "destroy",
                        GTK_SIGNAL_FUNC(lcl_onDestroy), NULL );
}

SAL_DLLPUBLIC_EXPORT GtkWidget* lok_docview_new( LibreOfficeKit* pOffice )
{
    LOKDocView* pDocView = gtk_type_new( lok_docview_get_type() );
    pDocView->pOffice = pOffice;
    return GTK_WIDGET( pDocView );
}

// We know that VirtualDevises use a DPI of 96.
static const int g_nDPI = 96;

/// Converts from document coordinates to screen pixels.
static float twipToPixel(float nInput)
{
    return nInput / 1440.0f * g_nDPI;
}

/// Converts from screen pixels to document coordinates
static float pixelToTwip(float nInput)
{
    return (nInput / g_nDPI) * 1440.0f;
}

void renderDocument(LOKDocView* pDocView, GdkRectangle* pPartial)
{
    long nDocumentWidthTwips, nDocumentHeightTwips, nDocumentWidthPixels, nDocumentHeightPixels;
    const int nTileSizePixels = 256;
    // Current row / column.
    guint nRow, nColumn;
    // Total number of rows / columns in this document.
    guint nRows, nColumns;

    // Get document size and find out how many rows / columns we need.
    pDocView->pDocument->pClass->getDocumentSize(pDocView->pDocument, &nDocumentWidthTwips, &nDocumentHeightTwips);
    nDocumentWidthPixels = twipToPixel(nDocumentWidthTwips) * pDocView->fZoom;
    nDocumentHeightPixels = twipToPixel(nDocumentHeightTwips) * pDocView->fZoom;
    nRows = ceil((double)nDocumentHeightPixels / nTileSizePixels);
    nColumns = ceil((double)nDocumentWidthPixels / nTileSizePixels);

    // Set up our table and the tile pointers.
    if (!pDocView->pTable)
        pPartial = NULL;
    if (pPartial)
    {
        // Same as nRows / nColumns, but from the previous renderDocument() call.
        guint nOldRows, nOldColumns;

        gtk_table_get_size(GTK_TABLE(pDocView->pTable), &nOldRows, &nOldColumns);
        if (nOldRows != nRows || nOldColumns != nColumns)
            // Can't do partial rendering, document size changed.
            pPartial = NULL;
    }
    if (!pPartial)
    {
        if (pDocView->pTable)
            gtk_container_remove(GTK_CONTAINER(pDocView->pEventBox), pDocView->pTable);
        pDocView->pTable = gtk_table_new(nRows, nColumns, FALSE);
        gtk_container_add(GTK_CONTAINER(pDocView->pEventBox), pDocView->pTable);
        gtk_widget_show(pDocView->pTable);
        if (pDocView->pCanvas)
            g_free(pDocView->pCanvas);
        pDocView->pCanvas = g_malloc0(sizeof(GtkWidget*) * nRows * nColumns);
    }

    // Render the tiles.
    for (nRow = 0; nRow < nRows; ++nRow)
    {
        for (nColumn = 0; nColumn < nColumns; ++nColumn)
        {
            int nTileWidthPixels, nTileHeightPixels;
            GdkPixbuf* pPixBuf;
            unsigned char* pBuffer;
            int nRowStride;
            GdkRectangle aTileRectangle;
            gboolean bPaint = TRUE;

            // Determine size of the tile: the rightmost/bottommost tiles may be smaller and we need the size to decide if we need to repaint.
            if (nColumn == nColumns - 1)
                nTileWidthPixels = nDocumentWidthPixels - nColumn * nTileSizePixels;
            else
                nTileWidthPixels = nTileSizePixels;
            if (nRow == nRows - 1)
                nTileHeightPixels = nDocumentHeightPixels - nRow * nTileSizePixels;
            else
                nTileHeightPixels = nTileSizePixels;

            // Determine size and position of the tile in document coordinates, so we can decide if we can skip painting for partial rendering.
            aTileRectangle.x = pixelToTwip(nTileSizePixels) / pDocView->fZoom * nColumn;
            aTileRectangle.y = pixelToTwip(nTileSizePixels) / pDocView->fZoom * nRow;
            aTileRectangle.width = pixelToTwip(nTileWidthPixels) / pDocView->fZoom;
            aTileRectangle.height = pixelToTwip(nTileHeightPixels) / pDocView->fZoom;
            if (pPartial && !gdk_rectangle_intersect(pPartial, &aTileRectangle, NULL))
                    bPaint = FALSE;

            if (bPaint)
            {
                pPixBuf = gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8, nTileWidthPixels, nTileHeightPixels);
                pBuffer = gdk_pixbuf_get_pixels(pPixBuf);
                pDocView->pDocument->pClass->paintTile(pDocView->pDocument,
                                                       // Buffer and its size, depends on the position only.
                                                       pBuffer,
                                                       nTileWidthPixels, nTileHeightPixels,
                                                       &nRowStride,
                                                       // Position of the tile.
                                                       aTileRectangle.x, aTileRectangle.y,
                                                       // Size of the tile, depends on the zoom factor and the tile position only.
                                                       aTileRectangle.width, aTileRectangle.height);
                (void) nRowStride;

                if (pDocView->pCanvas[nRow * nColumns + nColumn])
                    gtk_widget_destroy(GTK_WIDGET(pDocView->pCanvas[nRow * nColumns + nColumn]));
                pDocView->pCanvas[nRow * nColumns + nColumn] = gtk_image_new();
                gtk_image_set_from_pixbuf(GTK_IMAGE(pDocView->pCanvas[nRow * nColumns + nColumn]), pPixBuf);
                g_object_unref(G_OBJECT(pPixBuf));
                gtk_widget_show(pDocView->pCanvas[nRow * nColumns + nColumn]);
                gtk_table_attach_defaults(GTK_TABLE(pDocView->pTable), pDocView->pCanvas[nRow * nColumns + nColumn], nColumn, nColumn + 1, nRow, nRow + 1);
                gtk_table_attach(GTK_TABLE(pDocView->pTable),
                                 pDocView->pCanvas[nRow * nColumns + nColumn],
                                 nColumn, nColumn + 1, nRow, nRow + 1,
                                 GTK_SHRINK, GTK_SHRINK, 0, 0);
            }
        }
    }
}

/// Callback data, allocated in lok_docview_callback_worker(), released in lok_docview_callback().
typedef struct
{
    int m_nType;
    char* m_pPayload;
    LOKDocView* m_pDocView;
}
LOKDocViewCallbackData;

/// Returns the GdkRectangle of a width,height,x,y string.
static GdkRectangle lcl_payloadToRectangle(const char* pPayload)
{
    GdkRectangle aRet;
    gchar** ppCoordinates;

    ppCoordinates = g_strsplit(pPayload, ", ", 4);
    if (!*ppCoordinates)
        return aRet;
    aRet.width = atoi(*ppCoordinates);
    ++ppCoordinates;
    if (!*ppCoordinates)
        return aRet;
    aRet.height = atoi(*ppCoordinates);
    ++ppCoordinates;
    if (!*ppCoordinates)
        return aRet;
    aRet.x = atoi(*ppCoordinates);
    ++ppCoordinates;
    if (!*ppCoordinates)
        return aRet;
    aRet.y = atoi(*ppCoordinates);
    return aRet;
}

/// Invoked on the main thread if lok_docview_callback_worker() requests so.
static gboolean lok_docview_callback(gpointer pData)
{
    LOKDocViewCallbackData* pCallback = pData;

    switch (pCallback->m_nType)
    {
    case LOK_CALLBACK_INVALIDATE_TILES:
    {
        if (strcmp(pCallback->m_pPayload, "EMPTY") != 0)
        {
            GdkRectangle aRectangle = lcl_payloadToRectangle(pCallback->m_pPayload);
            renderDocument(pCallback->m_pDocView, &aRectangle);
        }
        else
            renderDocument(pCallback->m_pDocView, NULL);
    }
    break;
    default:
        break;
    }

    g_free(pCallback->m_pPayload);
    g_free(pCallback);
    return G_SOURCE_REMOVE;
}

/// Our LOK callback, runs on the LO thread.
static void lok_docview_callback_worker(int nType, const char* pPayload, void* pData)
{
    LOKDocView* pDocView = pData;

    LOKDocViewCallbackData* pCallback = g_new0(LOKDocViewCallbackData, 1);
    pCallback->m_nType = nType;
    pCallback->m_pPayload = g_strdup(pPayload);
    pCallback->m_pDocView = pDocView;
#if GTK_CHECK_VERSION(2,12,0)
    gdk_threads_add_idle(lok_docview_callback, pCallback);
#else
    g_idle_add(lok_docview_callback, pDocView);
#endif
}

SAL_DLLPUBLIC_EXPORT gboolean lok_docview_open_document( LOKDocView* pDocView, char* pPath )
{
    if ( pDocView->pDocument )
    {
        pDocView->pDocument->pClass->destroy( pDocView->pDocument );
        pDocView->pDocument = NULL;
    }

    pDocView->pDocument = pDocView->pOffice->pClass->documentLoad( pDocView->pOffice,
                                                                   pPath );
    if ( !pDocView->pDocument )
    {
        // FIXME: should have a GError parameter and populate it.
        char *pError = pDocView->pOffice->pClass->getError( pDocView->pOffice );
        fprintf( stderr, "Error opening document '%s'\n", pError );
        return FALSE;
    }
    else
    {
        pDocView->pDocument->pClass->initializeForRendering(pDocView->pDocument);
        renderDocument(pDocView, NULL);
    }

    return TRUE;
}

SAL_DLLPUBLIC_EXPORT void lok_docview_set_zoom ( LOKDocView* pDocView, float fZoom )
{
    pDocView->fZoom = fZoom;

    if ( pDocView->pDocument )
    {
        renderDocument(pDocView, NULL);
    }
    // TODO: maybe remember and reset positiong?
}

SAL_DLLPUBLIC_EXPORT float lok_docview_get_zoom ( LOKDocView* pDocView )
{
    return pDocView->fZoom;
}

SAL_DLLPUBLIC_EXPORT int lok_docview_get_parts( LOKDocView* pDocView )
{
    return pDocView->pDocument->pClass->getParts( pDocView->pDocument );
}

SAL_DLLPUBLIC_EXPORT int lok_docview_get_part( LOKDocView* pDocView )
{
    return pDocView->pDocument->pClass->getPart( pDocView->pDocument );
}

SAL_DLLPUBLIC_EXPORT void lok_docview_set_part( LOKDocView* pDocView, int nPart)
{
    pDocView->pDocument->pClass->setPart( pDocView->pDocument, nPart );
    renderDocument(pDocView, NULL);
}

SAL_DLLPUBLIC_EXPORT char* lok_docview_get_part_name( LOKDocView* pDocView, int nPart )
{
    return pDocView->pDocument->pClass->getPartName( pDocView->pDocument, nPart );
}

SAL_DLLPUBLIC_EXPORT void lok_docview_set_partmode( LOKDocView* pDocView,
                                                    LibreOfficeKitPartMode ePartMode )
{
    pDocView->pDocument->pClass->setPartMode( pDocView->pDocument, ePartMode );
    renderDocument(pDocView, NULL);
}

SAL_DLLPUBLIC_EXPORT void lok_docview_set_edit( LOKDocView* pDocView,
                                                gboolean bEdit )
{
    if (!pDocView->m_bEdit && bEdit)
        pDocView->pDocument->pClass->registerCallback(pDocView->pDocument, &lok_docview_callback_worker, pDocView);
    pDocView->m_bEdit = bEdit;
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */