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

"""
***************************************************************************
    RandomPointsLayer.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 processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.ProcessingLog import ProcessingLog
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterNumber
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector


class RandomPointsLayer(GeoAlgorithm):

    VECTOR = 'VECTOR'
    POINT_NUMBER = 'POINT_NUMBER'
    MIN_DISTANCE = 'MIN_DISTANCE'
    OUTPUT = 'OUTPUT'

    def defineCharacteristics(self):
        self.name = 'Random points in layer bounds'
        self.group = 'Vector creation tools'
        self.addParameter(ParameterVector(self.VECTOR,
            'Input layer',[ParameterVector.VECTOR_TYPE_POLYGON]))
        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):
        layer = dataobjects.getObjectFromUri(
            self.getParameterValue(self.VECTOR))
        pointCount = int(self.getParameterValue(self.POINT_NUMBER))
        minDistance = float(self.getParameterValue(self.MIN_DISTANCE))

        bbox = layer.extent()
        extent = QgsGeometry().fromRect(bbox)
        idxLayer = vector.spatialindex(layer)

        fields = QgsFields()
        fields.append(QgsField('id', QVariant.Int, '', 10, 0))
        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
            fields, QGis.WKBPoint, layer.dataProvider().crs())

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

        index = QgsSpatialIndex()
        points = dict()

        request = QgsFeatureRequest()

        random.seed()

        while nIterations < maxIterations and nPoints < pointCount:
            rx = bbox.xMinimum() + bbox.width() * random.random()
            ry = bbox.yMinimum() + bbox.height() * random.random()

            pnt = QgsPoint(rx, ry)
            geom = QgsGeometry.fromPoint(pnt)
            ids = idxLayer.intersects(geom.buffer(5, 5).boundingBox())
            if len(ids) > 0 and \
                    vector.checkMinDistance(pnt, index, minDistance, points):
                for i in ids:
                    f = layer.getFeatures(request.setFilterFid(i)).next()
                    tmpGeom = QgsGeometry(f.geometry())
                    if geom.within(tmpGeom):
                        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