##| Copyright: (C) 2019-2020 Kevin Larke <contact AT larke DOT org> 
##| License: GNU GPL version 3.0 or above. See the accompanying LICENSE file.

import sys,os
import numpy as np
import common
import rms_analysis



def fit_points_to_reference( usL, dbL, usRefL, dbRefL ):

    dbV = None
    
    yyL = [ (db,dbRefL[ usRefL.index(us)]) for i,(us,db) in enumerate(zip(usL,dbL)) if us in usRefL ]

    if len(yyL) < 10:
        print("NO FIT")
    else:

        y0L,yrL = zip(*yyL)
        yN = len(y0L)
        
        A = np.vstack([np.ones(yN),y0L]).T
        c,m = np.linalg.lstsq(A,yrL,rcond=None)[0]

        dbV = (np.array(dbL) * m) + c


    return dbV

def find_elbow( usL, dbL, pointsPerLine=10 ):
    
    ppl_2         = int(pointsPerLine/2)
    dL = []

    
    i = pointsPerLine

    # for each consecutive set of 'pointsPerLine' points in usL and dbL
    while i < len(usL):

        # find the x,y coordinates of the first 'ppl_2' coordinates
        x0L = np.array([ (us,1.0) for us in usL[i-pointsPerLine:i-ppl_2] ])
        y0L = np.array(usL[i-pointsPerLine:i-ppl_2])

        # find the x,y coordinates of the second 'ppl_2' coordinates
        x1L = np.array([ (us,1.0) for us in usL[i-ppl_2:i]])
        y1L = np.array(dbL[i-ppl_2:i])

        
        m0,c0   = np.linalg.lstsq(x0L,y0L,rcond=None)[0] # fit a line through the first set of points
        m1,c1   = np.linalg.lstsq(x1L,y1L,rcond=None)[0] # fit a line through the second set of points

        # store the angle between the two lines
        dL.append(m1-m0)

        i += 1

    # find the max angle
    i = np.argmax( dL )    

    # return the x,y coordinate of the first data point of the second line
    return (usL[i+ppl_2],dbL[i+ppl_2])
    
def find_elbow_main( cfg, inDir, midi_pitch, takeId ):

    inDir         = os.path.join(inDir,str(pitch),str(takeId))
    analysisArgsD = cfg.analysisArgs['rmsAnalysArgs']
     
    r = rms_analysis_main( inDir, int(midi_pitch), **analysisD )

    usL = r.pkUsL
    dbL = r.pkDbL
    
    return find_elbow(r.pkUsL,r.pkDbL)


if __name__ == "__main__":

    inDir = sys.argv[1]
    cfgFn = sys.argv[2]
    pitch = sys.argv[3]
    
    cfg = common.parse_yaml_cfg(cfgFn)

    find_elbow( cfg, inDir, pitch, 0 )