"""Define a helper function for running tests

The skeleton for making a new setup is as follows:

from ase.optimize.test import run_test

def get_atoms():
    return Atoms('H')

def get_calculator():
    return EMT()

run_test(get_atoms, get_calculator, 'Hydrogen')
"""

import time

import matplotlib
#matplotlib.rcParams['backend']="Agg"

from ase.optimize.bfgs import BFGS
from ase.optimize.lbfgs import LBFGS, LBFGSLineSearch
from ase.optimize.fire import FIRE
from ase.optimize.mdmin import MDMin
from ase.optimize.sciopt import SciPyFminCG
from ase.optimize.sciopt import SciPyFminBFGS
from ase.optimize.bfgslinesearch import BFGSLineSearch
from ase.optimize.oldqn import GoodOldQuasiNewton

from ase.parallel import rank, paropen

import matplotlib.pyplot as pl
import numpy as np

import traceback

optimizers = [
    'BFGS',
    'LBFGS',
    'LBFGSLineSearch',
    'FIRE',
    'MDMin',
    'SciPyFminCG',
    'SciPyFminBFGS',
    'BFGSLineSearch',
    'GoodOldQuasiNewton'
]

def get_optimizer(optimizer):
    if optimizer == 'BFGS': return BFGS
    elif optimizer == 'LBFGS': return LBFGS
    elif optimizer == 'LBFGSLineSearch': return LBFGSLineSearch
    elif optimizer == 'FIRE': return FIRE
    elif optimizer == 'MDMin': return MDMin
    elif optimizer == 'SciPyFminCG': return SciPyFminCG
    elif optimizer == 'SciPyFminBFGS': return SciPyFminBFGS
    elif optimizer == 'BFGSLineSearch': return BFGSLineSearch
    elif optimizer == 'GoodOldQuasiNewton': return GoodOldQuasiNewton

def run_test(get_atoms, get_calculator, name,
             fmax=0.05, steps=100, plot=True):

    plotter = Plotter(name, fmax)
    csvwriter = CSVWriter(name)
    # write header
    row = ['Optimizer', 'Optimizer Steps', 'Force evaluations', 'Energy']
    row.extend(['Time [sec]', 'Note'])
    format = '%s,%s,%s,%s,%s,%s\n'
    csvwriter.write(row, format)
    for optimizer in optimizers:
        note = ''
        logname = name + '-' + optimizer

        atoms = get_atoms()
        atoms.set_calculator(get_calculator())
        opt = get_optimizer(optimizer)
        relax = opt(atoms, logfile=None)
                    #logfile = logname + '.log',
                    #trajectory = logname + '.traj')

        obs = DataObserver(atoms)
        relax.attach(obs)
        t = time.time()
        try:
            relax.run(fmax = fmax, steps = steps)
            E = atoms.get_potential_energy()

            if relax.get_number_of_steps() == steps:
                note = 'Not converged in %i steps' % steps
        except Exception:
            traceback.print_exc()
            note = 'An exception occurred'
            E = np.nan
        t = time.time() - t

        nsteps = relax.get_number_of_steps()
        if hasattr(relax, 'force_calls'):
            fc = relax.force_calls
            if rank == 0:
                print('%-15s %-15s %3i %8.3f (%3i) %s' % (name, optimizer, nsteps, E, fc, note))
        else:
            fc = nsteps
            if rank == 0:
                print('%-15s %-15s %3i %8.3f       %s' % (name, optimizer, nsteps, E, note))

        plotter.plot(optimizer, obs.get_E(), obs.get_fmax())
        format = '%s,%i,%i,%.5f,%i,%s\n'
        row = [optimizer, nsteps, fc, E]
        row.extend([int(t), note])
        csvwriter.write(row, format)

    plotter.save()
    csvwriter.finalize()

class Plotter:
    def __init__(self, name, fmax):
        self.name = name
        self.fmax = fmax
        if rank == 0:
            self.fig = pl.figure(figsize=[12.0, 9.0])
            self.axes0 = self.fig.add_subplot(2, 1, 1)
            self.axes1 = self.fig.add_subplot(2, 1, 2)

    def plot(self, optimizer, E, fmax):
        if rank == 0:
            self.axes0.plot(E, label = optimizer)
            self.axes1.plot(fmax)

    def save(self, format='png'):
        if rank == 0:
            self.axes0.legend()
            self.axes0.set_title(self.name)
            self.axes0.set_ylabel('E [eV]')
            #self.axes0.set_yscale('log')

            self.axes1.set_xlabel('steps')
            self.axes1.set_ylabel('fmax [eV/A]')
            self.axes1.set_yscale('log')
            self.axes1.axhline(self.fmax, color='k', linestyle='--')
            self.fig.savefig(self.name + '.' + format)

class CSVWriter:
    def __init__(self, name):
        self.f = paropen(name + '.csv', 'w')

    def write(self, row, format):
        self.f.write(format % tuple(row))

    def finalize(self):
        self.f.close()

class DataObserver:
    def __init__(self, atoms):
        self.atoms = atoms
        self.E = []
        self.fmax = []

    def __call__(self):
        self.E.append(self.atoms.get_potential_energy())
        self.fmax.append(np.sqrt((self.atoms.get_forces()**2).sum(axis=1)).max())

    def get_E(self):
        return np.array(self.E)

    def get_fmax(self):
        return np.array(self.fmax)
