# -*- 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.                                   *
*                                                                         *
***************************************************************************
"""
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException

__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 PyQt4.QtCore import *
from PyQt4.QtGui import *
from qgis.core import *
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.tools import dataobjects, vector
from processing.parameters.ParameterVector import ParameterVector
from processing.parameters.ParameterTableField import ParameterTableField
from processing.parameters.ParameterSelection import ParameterSelection
from processing.outputs.OutputVector import OutputVector
from processing.tools import vector as utils

class ConvexHull(GeoAlgorithm):

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

    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 (optional, only used if creating convex hulls by classes)", ConvexHull.INPUT, optional = True))
        self.addParameter(ParameterSelection(ConvexHull.METHOD, "Method", ConvexHull.METHODS))
        self.addOutput(OutputVector(ConvexHull.OUTPUT, "Convex hull"))

    def processAlgorithm(self, progress):
        useField = (self.getParameterValue(ConvexHull.METHOD) == 1)
        fieldName = self.getParameterValue(ConvexHull.FIELD)
        layer = dataobjects.getObjectFromUri(self.getParameterValue(ConvexHull.INPUT))

        f = QgsField("value")
        f.setType(QVariant.String)
        f.setLength(255)
        if useField:
            index = layer.fieldNameIndex(fieldName)
            fType = layer.pendingFields()[index].type()
            if fType == QVariant.Int:
                f.setType(QVariant.Int)
                f.setLength(20)
            elif fType == QVariant.Double:
                f.setType(QVariant.Double)
                f.setLength(20)
                f.setPrecision(6)
            else:
                f.setType(QVariant.String)
                f.setLength(255)

        fields = [QgsField("id", QVariant.Int, "", 20),
                  f,
                  QgsField("area", QVariant.Double, "", 20, 6),
                  QgsField("perim", QVariant.Double, "", 20, 6)
                 ]

        writer = self.getOutputFromName(ConvexHull.OUTPUT).getVectorWriter(fields, QGis.WKBPolygon, layer.dataProvider().crs())

        outFeat = QgsFeature()
        inGeom = QgsGeometry()
        outGeom = QgsGeometry()

        current = 0

        fid = 0
        val = ""
        if useField:
            unique = layer.uniqueValues(index)
            total = 100.0 / float(layer.featureCount() * len (unique))

            for i in unique:
                hull = []
                first = True
                features = vector.features(layer)
                for f in features:
                    idVar = f[fieldName]
                    if unicode(idVar).strip() == unicode(i).strip:
                        if first:
                            val = idVar
                            first = False
                        inGeom = QgsGeometry(f.geometry())
                        points = utils.extractPoints(inGeom)
                        hull.extend(points)
                    current += 1
                    progress.setPercentage(int(current * total))

                if len(hull) >= 3:
                    tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
                    try:
                        outGeom = tmpGeom.convexHull()
                        (area, perim) = utils.simpleMeasure(outGeom)
                        outFeat.setGeometry(outGeom)
                        outFeat.setAttributes([fid,val,area,perim])
                        writer.addFeature(outFeat)
                    except:
                        raise GeoAlgorithmExecutionException("Exception while computing convex hull")
                fid += 1
        else:
          hull = []
          total = 100.0 / float(layer.featureCount())
          features = vector.features(layer)
          for f in features:
              inGeom = QgsGeometry(f.geometry())
              points = utils.extractPoints(inGeom)
              hull.extend(points)
              current += 1
              progress.setPercentage(int(current * total))

          tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
          try:
              outGeom = tmpGeom.convexHull()
              (area, perim) = utils.simpleMeasure(outGeom)
              outFeat.setGeometry(outGeom)
              outFeat.setAttributes([0, "all", area, perim])
              writer.addFeature(outFeat)
          except:
              raise GeoAlgorithmExecutionException("Exception while computing convex hull")

        del writer