# -*- coding: utf-8 -*-

"""
***************************************************************************
    ConvexHull.py
    ---------------------
    Date                 : August 2012
    Copyright            : (C) 2012 by Victor Olaya
    Email                : volayaf at gmail dot com
***************************************************************************
*                                                                         *
*   This program is free software; you can redistribute it and/or modify  *
*   it under the terms of the GNU General Public License as published by  *
*   the Free Software Foundation; either version 2 of the License, or     *
*   (at your option) any later version.                                   *
*                                                                         *
***************************************************************************
"""

__author__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'

from sextante.core.GeoAlgorithm import GeoAlgorithm
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from qgis.core import *
from sextante.parameters.ParameterVector import ParameterVector
from sextante.core.QGisLayers import QGisLayers
from sextante.outputs.OutputVector import OutputVector
from sextante.algs.ftools import ftools_utils
from sextante.core.SextanteLog import SextanteLog
from sextante.parameters.ParameterTableField import ParameterTableField
from sextante.parameters.ParameterSelection import ParameterSelection

class ConvexHull(GeoAlgorithm):

    INPUT = "INPUT"
    OUTPUT = "OUTPUT"
    FIELD = "FIELD"
    METHOD = "METHOD"
    METHODS = ["Create single minimum convex hull", "Create convex hulls based on field"]

    #===========================================================================
    # def getIcon(self):
    #    return QtGui.QIcon(os.path.dirname(__file__) + "/icons/convex_hull.png")
    #===========================================================================

    def processAlgorithm(self, progress):
        useField = (self.getParameterValue(ConvexHull.METHOD) == 1)
        field = self.getParameterValue(ConvexHull.FIELD)
        vlayerA = QGisLayers.getObjectFromUri(self.getParameterValue(ConvexHull.INPUT))
        GEOS_EXCEPT = True
        FEATURE_EXCEPT = True
        vproviderA = vlayerA.dataProvider()
        allAttrsA = vproviderA.attributeIndexes()
        vproviderA.select(allAttrsA)
        fields = { 0 : QgsField("ID", QVariant.Int),
                    1 : QgsField("Area", QVariant.Double),
                    2 : QgsField("Perim", QVariant.Double) }
        writer = self.getOutputFromName(ConvexHull.OUTPUT).getVectorWriter(fields, QGis.WKBPolygon, vproviderA.crs())
        inFeat = QgsFeature()
        outFeat = QgsFeature()
        inGeom = QgsGeometry()
        outGeom = QgsGeometry()
        nElement = 0
        index = vproviderA.fieldNameIndex(field)

        features = QGisLayers.features(vlayerA)
        nFeat = len(features)

        if useField:
          unique = ftools_utils.getUniqueValues(vproviderA, index)
          nFeat = nFeat * len(unique)
          for i in unique:
            hull = []
            first = True
            outID = 0
            vproviderA.select(allAttrsA)
            features = QGisLayers.features(vlayerA)
            for inFeat in features:
              atMap = inFeat.attributeMap()
              idVar = atMap[ index ]
              if idVar.toString().trimmed() == i.toString().trimmed():
                if first:
                  outID = idVar
                  first = False
                inGeom = QgsGeometry(inFeat.geometry())
                points = ftools_utils.extractPoints(inGeom)
                hull.extend(points)
              nElement += 1
              progress.setPercentage(int(nElement / nFeat * 100))
            if len(hull) >= 3:
              tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
              try:
                outGeom = tmpGeom.convexHull()
                outFeat.setGeometry(outGeom)
                (area, perim) = self.simpleMeasure(outGeom)
                outFeat.addAttribute(0, QVariant(outID))
                outFeat.addAttribute(1, QVariant(area))
                outFeat.addAttribute(2, QVariant(perim))
                writer.addFeature(outFeat)
              except:
                GEOS_EXCEPT = False
                continue
        else:
          hull = []
          vproviderA.select(allAttrsA)
          features = QGisLayers.features(vlayerA)
          for inFeat in features:
            inGeom = QgsGeometry(inFeat.geometry())
            points = ftools_utils.extractPoints(inGeom)
            hull.extend(points)
            nElement += 1
            progress.setPercentage(int(nElement / nFeat * 100))
          tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
          try:
            outGeom = tmpGeom.convexHull()
            outFeat.setGeometry(outGeom)
            writer.addFeature(outFeat)
          except:
            GEOS_EXCEPT = False

        del writer

        if not GEOS_EXCEPT:
            SextanteLog.addToLog(SextanteLog.LOG_WARNING, "Geometry exception while computing convex hull")
        if not FEATURE_EXCEPT:
            SextanteLog.addToLog(SextanteLog.LOG_WARNING, "Feature exception while computing convex hull")

    def simpleMeasure(self, inGeom):
        measure = QgsDistanceArea()
        attr1 = measure.measure(inGeom)
        if inGeom.type() == QGis.Polygon:
          attr2 = self.perimMeasure(inGeom, measure)
        else:
          attr2 = attr1
        return (attr1, attr2)

    def perimMeasure(self, inGeom, measure):
        value = 0.00
        if inGeom.isMultipart():
          poly = inGeom.asMultiPolygon()
          for k in poly:
            for j in k:
              value = value + measure.measureLine(j)
        else:
          poly = inGeom.asPolygon()
          for k in poly:
            value = value + measure.measureLine(k)
        return value

    def defineCharacteristics(self):
        self.name = "Convex hull"
        self.group = "Vector geometry tools"
        self.addParameter(ParameterVector(ConvexHull.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_ANY))
        self.addParameter(ParameterTableField(ConvexHull.FIELD, "Field", ConvexHull.INPUT))
        self.addParameter(ParameterSelection(ConvexHull.METHOD, "Method", ConvexHull.METHODS))
        self.addOutput(OutputVector(ConvexHull.OUTPUT, "Convex hull"))
    #=========================================================