/*
    Copyright 2010 Google Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

         http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
 */


#include "GrAtlas.h"
#include "GrClipIterator.h"
#include "GrContext.h"
#include "GrTextContext.h"
#include "GrTextStrike.h"
#include "GrTextStrike_impl.h"
#include "GrFontScaler.h"

static const GrVertexLayout VLAYOUT = GrDrawTarget::kTextFormat_VertexLayoutBit;

void GrTextContext::flushGlyphs() {
    if (fCurrVertex > 0) {
        GrDrawTarget::AutoStateRestore asr(fDrawTarget);

        // setup our sampler state for our text texture/atlas

        GrSamplerState sampler(GrSamplerState::kRepeat_WrapMode,
                               GrSamplerState::kRepeat_WrapMode,
                               GrSamplerState::kAlphaMod_SampleMode,
                               !fExtMatrix.isIdentity());
        fDrawTarget->setSamplerState(sampler);

        GrAssert(GrIsALIGN4(fCurrVertex));
        int nIndices = fCurrVertex + (fCurrVertex >> 1);
        GrAssert(fCurrTexture);
        fDrawTarget->setTexture(fCurrTexture);
        fDrawTarget->setTextureMatrix(GrMatrix::I());
        fDrawTarget->setIndexSourceToBuffer(fContext->quadIndexBuffer());

        fDrawTarget->drawIndexed(GrDrawTarget::kTriangles_PrimitiveType,
                                 0, 0, fCurrVertex, nIndices);

        fDrawTarget->releaseReservedGeometry();
        fVertices = NULL;
        fMaxVertices = 0;
        fCurrVertex = 0;
        fCurrTexture->unref();
        fCurrTexture = NULL;
    }
}

GrTextContext::GrTextContext(GrContext* context, const GrMatrix* extMatrix) {
    fContext = context;
    fStrike = NULL;

    fCurrTexture = NULL;
    fCurrVertex = 0;
    fClipRect = context->getClip().getBounds();

    if (NULL != extMatrix) {
        fExtMatrix = *extMatrix;
    } else {
        fExtMatrix = GrMatrix::I();
    }
    if (!fExtMatrix.isIdentity()) {
        GrMatrix inverse;
        GrRect r;
        r.set(fClipRect);
        if (fExtMatrix.invert(&inverse)) {
            inverse.mapRect(&r);
            r.roundOut(&fClipRect);
        }
    }

    fContext->getViewMatrix(&fOrigViewMatrix);
    fContext->setViewMatrix(fExtMatrix);

    fVertices = NULL;
    fMaxVertices = 0;
    fDrawTarget = fContext->getTextTarget();
}

GrTextContext::~GrTextContext() {
    this->flushGlyphs();
    fContext->setViewMatrix(fOrigViewMatrix);
}

void GrTextContext::flush() {
    this->flushGlyphs();
}

static inline void setRectFan(GrGpuTextVertex v[4], int l, int t, int r, int b,
                              int stride) {
    v[0 * stride].setI(l, t);
    v[1 * stride].setI(l, b);
    v[2 * stride].setI(r, b);
    v[3 * stride].setI(r, t);
}

void GrTextContext::drawPackedGlyph(GrGlyph::PackedID packed,
                                    GrFixed vx, GrFixed vy,
                                    GrFontScaler* scaler) {
    if (NULL == fStrike) {
        fStrike = fContext->getFontCache()->getStrike(scaler);
    }

    GrGlyph* glyph = fStrike->getGlyph(packed, scaler);
    if (NULL == glyph || glyph->fBounds.isEmpty()) {
        return;
    }

    vx += GrIntToFixed(glyph->fBounds.fLeft);
    vy += GrIntToFixed(glyph->fBounds.fTop);

    // keep them as ints until we've done the clip-test
    GrFixed width = glyph->fBounds.width();
    GrFixed height = glyph->fBounds.height();

    // check if we clipped out
    if (true || NULL == glyph->fAtlas) {
        int x = vx >> 16;
        int y = vy >> 16;
        if (fClipRect.quickReject(x, y, x + width, y + height)) {
//            Gr_clz(3);    // so we can set a break-point in the debugger
            return;
        }
    }

    if (NULL == glyph->fAtlas) {
        if (fStrike->getGlyphAtlas(glyph, scaler)) {
            goto HAS_ATLAS;
        }
        // try to purge
        fContext->getFontCache()->purgeExceptFor(fStrike);
        if (fStrike->getGlyphAtlas(glyph, scaler)) {
            goto HAS_ATLAS;
        }

        // Draw as a path, so we flush any accumulated glyphs first
        this->flushGlyphs();

        if (NULL == glyph->fPath) {

            GrPath* path = new GrPath;
            if (!scaler->getGlyphPath(glyph->glyphID(), path)) {
                // flag the glyph as being dead?
                delete path;
                return;
            }
            glyph->fPath = path;
        }
        GrPath::Iter iter(*glyph->fPath);
        bool useTexture = false;
        GrPoint translate;
        translate.set(GrFixedToScalar(vx - GrIntToFixed(glyph->fBounds.fLeft)),
                      GrFixedToScalar(vy - GrIntToFixed(glyph->fBounds.fTop)));
        fContext->drawPath(&iter, GrContext::kWinding_PathFill,
                              useTexture, &translate);
        return;
    }

HAS_ATLAS:
    GrAssert(glyph->fAtlas);

    // now promote them to fixed
    width = GrIntToFixed(width);
    height = GrIntToFixed(height);

    GrTexture* texture = glyph->fAtlas->texture();
    GrAssert(texture);

    if (fCurrTexture != texture || fCurrVertex + 4 > fMaxVertices) {
        this->flushGlyphs();
        fCurrTexture = texture;
        fCurrTexture->ref();
    }

    if (NULL == fVertices) {
        // If we need to reserve vertices allow the draw target to suggest
        // a number of verts to reserve and whether to perform a flush.
        fMaxVertices = kMinRequestedVerts;
        bool flush = fDrawTarget->geometryHints(VLAYOUT,
                                               &fMaxVertices,
                                               NULL);
        if (flush) {
            this->flushGlyphs();
            fContext->flushText();
            fDrawTarget = fContext->getTextTarget();
            fMaxVertices = kDefaultRequestedVerts;
            // ignore return, no point in flushing again.
            fDrawTarget->geometryHints(VLAYOUT,
                                       &fMaxVertices,
                                       NULL);
        }

        if (fMaxVertices < kMinRequestedVerts) {
            fMaxVertices = kDefaultRequestedVerts;
        } else if (fMaxVertices > (fContext->maxQuadsInIndexBuffer() * 4)) {
            // don't exceed the limit of the index buffer
            fMaxVertices = (fContext->maxQuadsInIndexBuffer() * 4);
        }
        bool success = fDrawTarget->reserveAndLockGeometry(VLAYOUT,
                                                           fMaxVertices, 0,
                                                           (void**)&fVertices,
                                                           NULL);
        GrAlwaysAssert(success);
    }

    GrFixed tx = GrIntToFixed(glyph->fAtlasLocation.fX);
    GrFixed ty = GrIntToFixed(glyph->fAtlasLocation.fY);

#if GR_GL_TEXT_TEXTURE_NORMALIZED
    int x = vx >> 16;
    int y = vy >> 16;
    int w = width >> 16;
    int h = height >> 16;

    setRectFan(&fVertices[2*fCurrVertex], x, y, x + w, y + h, 2);
    setRectFan(&fVertices[2*fCurrVertex+1],
               texture->normalizeFixedX(tx),
               texture->normalizeFixedY(ty),
               texture->normalizeFixedX(tx + width),
               texture->normalizeFixedY(ty + height),
               2);
#else
    fVertices[2*fCurrVertex].setXRectFan(vx, vy, vx + width, vy + height,
                                        2 * sizeof(GrGpuTextVertex));
    fVertices[2*fCurrVertex+1].setXRectFan(texture->normalizeFixedX(tx),
                                          texture->normalizeFixedY(ty),
                                          texture->normalizeFixedX(tx + width),
                                          texture->normalizeFixedY(ty + height),
                                          2 * sizeof(GrGpuTextVertex));
#endif
    fCurrVertex += 4;
}