'''Test the constraint behavior of an OPF'''
from minpower import powersystems
from minpower.optimization import value
from minpower.commonscripts import Series
from minpower.config import user_config

from test_utils import (istest, get_duals, with_setup, reset_config,
                        make_cheap_gen, make_mid_gen, make_expensive_gen,
                        singletime, make_loads_times,
                        solve_problem)


def test_config():
    assert(user_config.duals == False)


@istest
@with_setup(get_duals, reset_config)
def line_limit_high():
    '''
    Create a two bus system
        -cheap gen on busA
        -expensive gen and load on busB, 
        -line limit lower than load
    Ensure that: 
        - the line is at its limit 
        - the congestion price is equal to the diff. in LMPs
    '''
    pmax = 100
    generators = [
        make_cheap_gen(bus='A'),
        make_expensive_gen(bus='B')
    ]

    lines = [powersystems.Line(pmax=pmax, frombus='A', tobus='B')]
    power_system, times = solve_problem(generators, do_reset_config=False,
                                        lines=lines, **make_loads_times(Pd=225, bus='B'))
    Pline = value(lines[0].power(times[0]))
    lmps = [b.price(times[0]) for b in power_system.buses]
    congestion_price = lines[0].price(times[0])
    assert Pline == pmax and congestion_price == (lmps[1] - lmps[0])


@istest
@with_setup(get_duals, reset_config)
def line_limit_low():
    '''
    Create a two bus system
        -cheap gen on busA
        -expensive gen and load on busB, 
        -line (from B to A) limit lower than load
    Ensure that: 
        - the line is at its limit 
        - the congestion price is equal to the diff. in LMPs
    '''
    pmin = -100
    generators = [
        make_cheap_gen(bus='A'),
        make_expensive_gen(bus='B')
    ]
    lines = [powersystems.Line(pmin=pmin, frombus='B', tobus='A')]
    power_system, times = solve_problem(generators, do_reset_config=False,
                                        lines=lines, **make_loads_times(Pd=225, bus='B'))
    Pline = lines[0].power(times[0])
    lmps = [b.price(times[0]) for b in power_system.buses]
    congestion_price = lines[0].price(times[0])
    assert Pline == pmin and congestion_price == -1 * (lmps[1] - lmps[0])


@istest
@with_setup(get_duals, reset_config)
def three_buses():
    '''
    Create a three bus system
        -cheap gen and load on busA
        -mid gen and load on busB
        -expensive gen and load on busC
        -three lines connecting all three buses (triangle)
        -create congestion by setting a line limit
    Ensure that: 
        - the total load is met
        - the lmps are different
    '''
    pmax = 50
    Pd = [105, 225, 302]
    generators = [
        make_cheap_gen(bus='A'),
        make_mid_gen(bus='B'),
        make_expensive_gen(bus='C'),
    ]
    loads = [
        powersystems.Load(schedule=Series(Pd[0], singletime), bus='A'),
        powersystems.Load(schedule=Series(Pd[1], singletime), bus='B'),
        powersystems.Load(schedule=Series(Pd[2], singletime), bus='C')
    ]
    lines = [
        powersystems.Line(frombus='A', tobus='B'),
        powersystems.Line(frombus='A', tobus='C', pmax=pmax),
        powersystems.Line(frombus='B', tobus='C', pmax=pmax),
    ]
    power_system, times = solve_problem(generators, do_reset_config=False,
                                        times=singletime, loads=loads, lines=lines)
    num_lmps = len(set(b.price(times[0]) for b in power_system.buses))
    total_load = value(sum(b.Pload(times[0]) for b in power_system.buses))
    assert total_load == sum(Pd) and num_lmps > 1


def test_config_cleared():
    assert(user_config.duals == False)
