/*
 * Copyright (c) 2010-2012 OTClient <https://github.com/edubart/otclient>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "mapview.h"

#include <framework/graphics/graphics.h>
#include <framework/graphics/framebuffer.h>
#include <framework/graphics/paintershaderprogram.h>
#include <framework/graphics/paintershadersources.h>
#include "creature.h"
#include "map.h"
#include "tile.h"
#include "statictext.h"
#include "animatedtext.h"

MapView::MapView()
{
    int frameBufferSize = std::min(g_graphics.getMaxTextureSize(), (int)DEFAULT_FRAMBUFFER_SIZE);

    m_framebuffer = FrameBufferPtr(new FrameBuffer(Size(frameBufferSize, frameBufferSize)));
    m_framebuffer->setClearColor(Fw::black);
    m_lockedFirstVisibleFloor = -1;
    setVisibleDimension(Size(15, 11));

    m_shaderProgram = PainterShaderProgramPtr(new PainterShaderProgram);
    m_shaderProgram->addShaderFromSourceCode(Shader::Vertex, glslMainWithTexCoordsVertexShader + glslPositionOnlyVertexShader);
    m_shaderProgram->addShaderFromSourceFile(Shader::Fragment, "/game_shaders/map.frag");
    assert(m_shaderProgram->link());
}

void MapView::draw(const Rect& rect)
{
    // update visible tiles cache when needed
    bool updated = updateVisibleTilesCache();

    float scaleFactor = m_tileSize/(float)Otc::TILE_PIXELS;
    Position cameraPosition = getCameraPosition();

    int tileDrawFlags = 0;
    if(isNearView())
        tileDrawFlags = Otc::DrawGround | Otc::DrawWalls | Otc::DrawCommonItems | Otc::DrawCreatures | Otc::DrawEffects;
    else if(isMidView())
        tileDrawFlags = Otc::DrawGround | Otc::DrawWalls | Otc::DrawCommonItems | Otc::DrawCreatures;
    else if(isFarView())
        tileDrawFlags = Otc::DrawGround | Otc::DrawWalls;
    else // huge far view
        tileDrawFlags = Otc::DrawGround;

    bool animate = m_animated;

    // avoid animation of mid/far views
    if(!isNearView())
        animate = false;

    if(updated || animate) {
        m_framebuffer->bind();
        for(const TilePtr& tile : m_cachedVisibleTiles) {
            tile->draw(transformPositionTo2D(tile->getPosition()), scaleFactor, tileDrawFlags);
            //TODO: restore missiles
        }
        m_framebuffer->generateMipmaps();

        m_framebuffer->release();
    }

    g_painter.setCustomProgram(m_shaderProgram);
    g_painter.setColor(Fw::white);

    Point drawOffset(m_tileSize, m_tileSize);
    if(m_followingCreature)
        drawOffset += m_followingCreature->getWalkOffset() * scaleFactor;
    Rect srcRect = Rect(drawOffset, m_visibleDimension * m_tileSize);
    m_framebuffer->draw(rect, srcRect);

    g_painter.releaseCustomProgram();

    // this could happen if the player position is not known yet
    if(!cameraPosition.isValid())
        return;

    float horizontalStretchFactor = rect.width() / (float)(m_visibleDimension.width() * m_tileSize);
    float verticalStretchFactor = rect.height() / (float)(m_visibleDimension.height() * m_tileSize);
    Size tileStretchedSize = Size(m_tileSize * horizontalStretchFactor, m_tileSize * verticalStretchFactor);

    // avoid drawing texts on map in far zoom outs
    if(tileStretchedSize.width() >= 24) {
        for(const CreaturePtr& creature : m_cachedFloorVisibleCreatures) {
            const TilePtr& tile = creature->getCurrentTile();
            Position pos = tile->getPosition();

            Point p = transformPositionTo2D(pos) - drawOffset;
            p += (creature->getWalkOffset()-tile->getDrawElevation() + Point(8, -8)) * scaleFactor;
            p.x = p.x * horizontalStretchFactor;
            p.y = p.y * verticalStretchFactor;
            p += rect.topLeft();

            creature->drawInformation(p, g_map.isCovered(pos, m_cachedFirstVisibleFloor), rect);
        }

        for(const StaticTextPtr& staticText : g_map.getStaticTexts()) {
            Position pos = staticText->getPosition();

            // ony draw static texts from current camera floor, unless yells
            if(pos.z != getCameraPosition().z && !staticText->isYell())
                continue;

            Point p = transformPositionTo2D(pos) - drawOffset;
            p.x = p.x * horizontalStretchFactor;
            p.y = p.y * verticalStretchFactor;
            p += rect.topLeft();
            staticText->draw(p, rect);
        }

        for(const AnimatedTextPtr& animatedText : g_map.getAnimatedTexts()) {
            Position pos = animatedText->getPosition();

            // only draw animated texts from visible floors
            if(pos.z < m_cachedFirstVisibleFloor || pos.z > m_cachedLastVisibleFloor)
                continue;

            Point p = transformPositionTo2D(pos) - drawOffset;
            p.x = p.x * horizontalStretchFactor;
            p.y = p.y * verticalStretchFactor;
            p += rect.topLeft();
            animatedText->draw(p, rect);
        }
    }

    // draw a arrow for position the center in non near views
    if(!isNearView()) {
        g_painter.setColor(Fw::red);
        g_painter.drawFilledRect(Rect(rect.center(), 4, 4));
    }
}

bool MapView::updateVisibleTilesCache()
{
    // update only when needed
    if(!m_mustUpdateVisibleTilesCache)
        return false;

    int firstFloor = getFirstVisibleFloor();
    int lastFloor = getLastVisibleFloor();

    if(lastFloor < firstFloor)
        lastFloor = firstFloor;

    m_cachedFirstVisibleFloor = firstFloor;
    m_cachedLastVisibleFloor = lastFloor;
    Position cameraPosition = getCameraPosition();

    // clear current visible tiles cache
    m_cachedVisibleTiles.clear();
    m_cachedFloorVisibleCreatures.clear();

    // there is no tile to render on invalid positions
    if(!cameraPosition.isValid())
        return true;

    // cache visible tiles in draw order
    // draw from last floor (the lower) to first floor (the higher)
    for(int iz = m_cachedLastVisibleFloor; iz >= m_cachedFirstVisibleFloor; --iz) {
        // draw tiles like linus pauling's rule order
        const int numDiagonals = m_drawDimension.width() + m_drawDimension.height() - 1;
        for(int diagonal = 0; diagonal < numDiagonals; ++diagonal) {
            // loop through / diagonal tiles
            for(int ix = std::min(diagonal, m_drawDimension.width() - 1), iy = std::max(diagonal - m_drawDimension.width() + 1, 0); ix >= 0 && iy < m_drawDimension.height(); --ix, ++iy) {
                // position on current floor
                Position tilePos = cameraPosition.translated(ix - m_virtualCenterOffset.x, iy - m_virtualCenterOffset.y);
                // adjust tilePos to the wanted floor
                tilePos.coveredUp(cameraPosition.z - iz);
                if(const TilePtr& tile = g_map.getTile(tilePos)) {
                    // skip tiles that have nothing
                    if(tile->getThingCount() == 0)
                        continue;
                    // skip tiles that are completely behind another tile
                    if(g_map.isCompletelyCovered(tilePos, firstFloor))
                        continue;
                    m_cachedVisibleTiles.push_back(tile);
                }
            }
        }
    }

    m_cachedFloorVisibleCreatures = g_map.getSpectators(cameraPosition, false);

    m_mustUpdateVisibleTilesCache = false;
    return true;
}

void MapView::recalculateTileSize()
{
    int possiblesTileSizes[] = {32,16,8,4,2,1};

    int foundSize = 0;
    for(int candidateTileSize : possiblesTileSizes) {
        Size candidateFramebufferSize = m_drawDimension * candidateTileSize;

        // found a valid size
        if(candidateFramebufferSize.width() <= m_framebuffer->getSize().width() && candidateFramebufferSize.height() <= m_framebuffer->getSize().height()) {
            foundSize = candidateTileSize;
            break;
        }
    }

    assert(foundSize > 0);
    m_tileSize = foundSize;
}

void MapView::onTileUpdate(const Position& pos)
{
    requestVisibleTilesCacheUpdate();
}

void MapView::lockFirstVisibleFloor(int firstVisibleFloor)
{
    m_lockedFirstVisibleFloor = firstVisibleFloor;
    requestVisibleTilesCacheUpdate();
}

void MapView::unlockFirstVisibleFloor()
{
    m_lockedFirstVisibleFloor = -1;
    requestVisibleTilesCacheUpdate();
}

void MapView::followCreature(const CreaturePtr& creature)
{
    m_followingCreature = creature;
    m_customCameraPosition = Position();
    requestVisibleTilesCacheUpdate();
}

void MapView::setCameraPosition(const Position& pos)
{
    m_customCameraPosition = pos;
    m_followingCreature = nullptr;
    requestVisibleTilesCacheUpdate();
}

void MapView::setVisibleDimension(const Size& visibleDimension)
{
    if(visibleDimension.width() % 2 != 1 || visibleDimension.height() % 2 != 1) {
        logTraceError("visible dimension must be odd");
        return;
    }

    if(visibleDimension.width() <= 3 || visibleDimension.height() <= 3) {
        logTraceError("cannot render less than 3x3 tiles");
        return;
    }

    m_visibleDimension = visibleDimension;
    m_drawDimension = visibleDimension + Size(3,3);
    m_virtualCenterOffset = (m_drawDimension/2 - Size(1,1)).toPoint();
    recalculateTileSize();

    requestVisibleTilesCacheUpdate();
}

int MapView::getFirstVisibleFloor()
{
    // return forced first visible floor
    if(m_lockedFirstVisibleFloor != -1)
        return m_lockedFirstVisibleFloor;

    Position cameraPosition = getCameraPosition();

    // avoid rendering multile floors on far views
    if(!isNearView())
        return cameraPosition.z;

    // if nothing is limiting the view, the first visible floor is 0
    int firstFloor = 0;

    // limits to underground floors while under sea level
    if(cameraPosition.z > Otc::SEA_FLOOR)
        firstFloor = cameraPosition.z - Otc::AWARE_UNDEGROUND_FLOOR_RANGE;

    // loop in 3x3 tiles around the camera
    for(int ix = -1; ix <= 1 && firstFloor < cameraPosition.z; ++ix) {
        for(int iy = -1; iy <= 1 && firstFloor < cameraPosition.z; ++iy) {
            Position pos = cameraPosition.translated(ix, iy);

            // process tiles that we can look through, e.g. windows, doors
            if((ix == 0 && iy == 0) || g_map.isLookPossible(pos)) {
                Position upperPos = pos;
                Position coveredPos = pos;

                while(coveredPos.coveredUp() && upperPos.up() && upperPos.z >= firstFloor) {
                    // check tiles physically above
                    TilePtr tile = g_map.getTile(upperPos);
                    if(tile && tile->limitsFloorsView()) {
                        firstFloor = upperPos.z + 1;
                        break;
                    }

                    // check tiles geometrically above
                    tile = g_map.getTile(coveredPos);
                    if(tile && tile->limitsFloorsView()) {
                        firstFloor = coveredPos.z + 1;
                        break;
                    }

                    if(upperPos.z == 0)
                        break;
                }
            }
        }
    }

    return firstFloor;
}

int MapView::getLastVisibleFloor()
{
    Position cameraPosition = getCameraPosition();

    // avoid rendering multile floors on far views
    if(!isNearView())
        return cameraPosition.z;

    // view only underground floors when below sea level
    if(cameraPosition.z > Otc::SEA_FLOOR)
        return cameraPosition.z + Otc::AWARE_UNDEGROUND_FLOOR_RANGE;
    else
        return Otc::SEA_FLOOR;
}

Position MapView::getCameraPosition()
{
    if(m_followingCreature)
        return m_followingCreature->getPosition();
    return m_customCameraPosition;
}

Point MapView::transformPositionTo2D(const Position& position)
{
    Position cameraPosition = getCameraPosition();
    return Point((m_virtualCenterOffset.x + (position.x - cameraPosition.x) - (cameraPosition.z - position.z)) * m_tileSize,
                 (m_virtualCenterOffset.y + (position.y - cameraPosition.y) - (cameraPosition.z - position.z)) * m_tileSize);
}