# -*- coding: utf-8 -*-
"""
Created on Tue Nov 13 15:53:23 2012

@author: pedroluizcoelhorodrigues
"""
import numpy as np
from bin16 import *

class Filter_Coefficients():
    """List of coefficients of a IIR filter of order 2"""
    def __init__(self,a0=0,a1=0,a2=0,b0=0,b1=0,b2=0):
        self.b0 = b0
        self.b1 = b1
        self.b2 = b2
        self.a0 = a0
        self.a1 = a1
        self.a2 = a2
        
class Filter(object):
    """Basic Filter of Order 2"""
    
    def __init__(self,Coefficients,x1=0,x2=0,y1=0,y2=0):
        self.Coefficients = Coefficients
        self.x1 = x1
        self.x2 = x2
        self.y1 = y1
        self.y2 = y2
        
    def print_coefficients(self):
        print 'a0 = ', self.Coefficients.a0
        print 'a1 = ', self.Coefficients.a1
        print 'a2 = ', self.Coefficients.a2
        print 'b0 = ', self.Coefficients.b0
        print 'b1 = ', self.Coefficients.b1
        print 'b2 = ', self.Coefficients.b2, "\n"
                      
    def convolve(self,input):
    
        B = np.array([self.Coefficients.b0,self.Coefficients.b1,self.Coefficients.b2])
        A = np.array([self.Coefficients.a1,self.Coefficients.a2])

        y = np.zeros(len(input))
        y[0] = round(1.0/(self.Coefficients.a0) * (np.dot(B,np.array([input[0],self.x1,self.x2])) - np.dot(A,np.array([self.y1,self.y2]))))
        y[0] = trunc16(y[0])
        y[1] = round(1.0/(self.Coefficients.a0) * (np.dot(B,np.array([input[1],input[0],self.x1])) - np.dot(A,np.array([y[0],self.y1]))))
        y[1] = trunc16(y[1])
        
        for j in range(2,len(input)):
            y[j] = trunc16(round(1.0/(self.Coefficients.a0) * (np.dot(B,np.array([input[j],input[j-1],input[j-2]])) - np.dot(A,np.array([y[j-1],y[j-2]]))))) 
    
        self.x1 = input[j]
        self.x2 = input[j-1]
        self.y1 = y[j]
        self.y2 = y[j-1]
        
        return y
        
    def reset(self):
        self.x1 = 0
        self.x2 = 0
        self.y1 = 0
        self.y2 = 0
        
    def impulsive_response(self, N):       
        delta = np.zeros(N)
        delta[0] = 1
        return self.convolve(delta)

class FilterGlobal(object):
    """Global filter with other basic filters (of order 2) in cascade"""    
    def __init__(self,Filters):
        self.Filter = Filters
    
    def convolve(self,x):
        y = np.zeros(len(x))
        y = self.Filter[0].convolve(x)
        if len(self.Filter) > 1:
            for j in range(1,len(self.Filter)):
                y = self.Filter[j].convolve(y)    
        return y
        
    def impulsive_response(self, N):
        delta = np.zeros(N)
        delta[0] = 1
        return self.convolve(delta)
        
    def reset(self):
        for j in range(len(self.Filter)):
            self.Filter[j].reset()