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

"""
***************************************************************************
    RandomPointsExtent.py
    ---------------------
    Date                 : April 2014
    Copyright            : (C) 2014 by Alexander Bruy
    Email                : alexander dot bruy 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__ = 'Alexander Bruy'
__date__ = 'April 2014'
__copyright__ = '(C) 2014, Alexander Bruy'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'

import math
import random

from PyQt4.QtCore import *

from qgis.core import *
from qgis.utils import iface

from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.ProcessingLog import ProcessingLog
from processing.core.parameters import ParameterExtent
from processing.core.parameters import ParameterNumber
from processing.core.outputs import OutputVector
from processing.tools import vector

class RandomPointsExtent(GeoAlgorithm):

    EXTENT = 'EXTENT'
    POINT_NUMBER = 'POINT_NUMBER'
    MIN_DISTANCE = 'MIN_DISTANCE'
    OUTPUT = 'OUTPUT'

    def defineCharacteristics(self):
        self.name = 'Random points in extent'
        self.group = 'Vector creation tools'
        self.addParameter(ParameterExtent(self.EXTENT, 'Input extent'))
        self.addParameter(
            ParameterNumber(self.POINT_NUMBER, 'Points number', 1, 9999999, 1))
        self.addParameter(ParameterNumber(
            self.MIN_DISTANCE, 'Minimum distance', 0.0, 9999999, 0.0))
        self.addOutput(OutputVector(self.OUTPUT, 'Random points'))

    def processAlgorithm(self, progress):
        pointCount = int(self.getParameterValue(self.POINT_NUMBER))
        minDistance = float(self.getParameterValue(self.MIN_DISTANCE))
        extent = str(self.getParameterValue(self.EXTENT)).split(',')

        xMin = float(extent[0])
        xMax = float(extent[1])
        yMin = float(extent[2])
        yMax = float(extent[3])
        extent = QgsGeometry().fromRect(
            QgsRectangle(xMin, yMin, xMax, yMax))

        fields = QgsFields()
        fields.append(QgsField('id', QVariant.Int, '', 10, 0))
        mapCRS = iface.mapCanvas().mapSettings().destinationCrs()
        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
            fields, QGis.WKBPoint, mapCRS)

        nPoints = 0
        nIterations = 0
        maxIterations = pointCount * 200
        total = 100.0 / pointCount

        index = QgsSpatialIndex()
        points = dict()

        random.seed()

        while nIterations < maxIterations and nPoints < pointCount:
            rx = xMin + (xMax - xMin) * random.random()
            ry = yMin + (yMax - yMin) * random.random()

            pnt = QgsPoint(rx, ry)
            geom = QgsGeometry.fromPoint(pnt)
            if geom.within(extent) and \
                    vector.checkMinDistance(pnt, index, minDistance, points):
                f = QgsFeature(nPoints)
                f.initAttributes(1)
                f.setFields(fields)
                f.setAttribute('id', nPoints)
                f.setGeometry(geom)
                writer.addFeature(f)
                index.insertFeature(f)
                points[nPoints] = pnt
                nPoints += 1
                progress.setPercentage(int(nPoints * total))
            nIterations += 1

        if nPoints < pointCount:
             ProcessingLog.addToLog(
                 ProcessingLog.LOG_INFO,
                 'Can not generate requested number of random points. Maximum '
                 'number of attempts exceeded.')

        del writer