#!/usr/bin/python
# Find the top of the valence band and the bottom of the conduction band from EIGENVAL  
# Usage: chmod +x gbandedges
#        gbandedges [path] [ef]
#        ef: trial Fermi energy
#        ef read from OUTCAR if not given
# Last modified on Jun.21,2014

from sys import argv, exit
from os import path

from tklib.tkapplication import tkApplication
from tklib.tkutils import terminate, pint, pfloat, getarg, getintarg, getfloatarg
from tklib.tkcrystal.tkvasp import tkVASP


infile = '.'
EF = None


infile = getarg(1, infile)
EF     = getfloatarg(2, EF)

def usage():
    print("Usage: gbandedges_tklib [path] [Ef]")
    print("       ef: trial Fermi energy")
    print("       ef will be taken from OUTCAR if not given")
    exit(0)


if len(argv) == 1:
    app.terminate("", usage = usage, pause = True)
    
app    = tkApplication()
logfile = 'gbandedges-out.txt'
print(f"Open logfile [{logfile}]")
app.redirect(targets = ["stdout", logfile], mode = 'w')

vasp = tkVASP()
CAR_path      = vasp.getdir(infile)
OUTCAR_path   = vasp.get_OUTCAR(CAR_path)
EIGENVAL_path = vasp.get_VASPPath(CAR_path, 'EIGENVAL')
print("")
print("args:", argv)
print(f"infile: {infile}")
print(f"CAR_path: {CAR_path}")
print(f"OUTCAR_path: {OUTCAR_path}")
print(f"EIGENVAL_path: {EIGENVAL_path}")
if EF is None:
    print(f"EF will be taken from [{OUTCAR_path}]")
else:
    print(f"EF: {EF} eV")

inf = vasp.gbandedges(CAR_path, OUTCAR_path, EIGENVAL_path, EF)
if inf is None:
    app.terminate('', pause = True)


print("")
print(f"nspin    : {inf['nspin']}")
print(f"nkpoint  : {inf['nkpoint']}")
print(f"nband    : {inf['nband']}")
print(f"nlines   : {inf['nlines']}")
print("")
print(f"Efermi   : {inf['EF']:.3f}")
print(f"N band   : {inf['nband']}")
print(f"N kpoint : {inf['nkpoint']}")
print(f"N spin   : {inf['nspin']}")
print("")
print(f"Band gap : {inf['Eg']:.3f}")
print("")
print(f"CBM:")
print(f"  Energy : {inf['ECBM']:.3f}")
print(f"  K point: #{inf['ik_CBM']} k={inf['k_CBM']}")
print(f"  Band   : {inf['iband_CBM']}")
print(f"  Spin   : {inf['spin_CBM']}")
print("")
print(f"VBM:")
print(f"  Energy : {inf['EVBM']:.3f}")
print(f"  K point: #{inf['ik_VBM']} k={inf['k_VBM']}")
print(f"  Band   : {inf['iband_VBM']}")
print(f"  Spin   : {inf['spin_VBM']}")


app.terminate(pause = True)