"""
This module contains a Solver baseclass and several implemented subclasses.

Solvers are used to with pywr.core.Model classes to solve the network
allocation problem every time step.

Currently there are only linear programme based solvers using,
    - GLPK
    - LPSolve55
"""

solver_registry = []


class Solver(object):
    """Solver base class from which all solvers should inherit"""
    name = 'default'

    def __init__(self, *args, **kwargs):
        pass

    def setup(self, model):
        raise NotImplementedError('Solver should be subclassed to provide setup()')

    def solve(self, model):
        raise NotImplementedError('Solver should be subclassed to provide solve()')

    def reset(self):
        raise NotImplementedError('Solver should be subclassed to provide reset()')

    @property
    def stats(self):
        return {}


# Attempt to import solvers. These will only be successful if they are built correctly.
try:
    from .cython_glpk import CythonGLPKSolver as cy_CythonGLPKSolver
except ImportError:
    pass
else:
    class CythonGLPKSolver(Solver):
        """Python wrapper of Cython GLPK solver.

        This is required to subclass Solver and get the metaclass magic.
        """
        name = 'glpk'

        def __init__(self, *args, **kwargs):
            super(CythonGLPKSolver, self).__init__(*args, **kwargs)
            self._cy_solver = cy_CythonGLPKSolver(**kwargs)

        def setup(self, model):
            return self._cy_solver.setup(model)

        def solve(self, model):
            return self._cy_solver.solve(model)

        def reset(self):
            return self._cy_solver.reset()

        def dump_mps(self, filename):
            return self._cy_solver.dump_mps(filename)

        def dump_lp(self, filename):
            return self._cy_solver.dump_lp(filename)

        def dump_glpk(self, filename):
            return self._cy_solver.dump_glpk(filename)

        def retry_solve():
            def fget(self):
                return self._cy_solver.retry_solve

            def fset(self, value):
                self._cy_solver.retry_solve = value

            return locals()
        retry_solve = property(**retry_solve())

        def save_routes_flows():
            def fget(self):
                return self._cy_solver.save_routes_flows

            def fset(self, value):
                self._cy_solver.save_routes_flows = value

            return locals()
        save_routes_flows = property(**save_routes_flows())

        @property
        def routes(self):
            return self._cy_solver.routes

        @property
        def routes_flows_array(self):
            return self._cy_solver.route_flows_arr

        @property
        def stats(self):
            return self._cy_solver.stats
    solver_registry.append(CythonGLPKSolver)


try:
    from .cython_lpsolve import CythonLPSolveSolver as cy_CythonLPSolveSolver
except ImportError:
    pass
else:
    class CythonLPSolveSolver(Solver):
        """Python wrapper of Cython LPSolve55 solver.

        This is required to subclass Solver and get the metaclass magic.
        """
        name = 'lpsolve'

        def __init__(self, *args, **kwargs):
            super(CythonLPSolveSolver, self).__init__(*args, **kwargs)
            self._cy_solver = cy_CythonLPSolveSolver(**kwargs)

        def setup(self, model):
            return self._cy_solver.setup(model)

        def solve(self, model):
            return self._cy_solver.solve(model)

        def reset(self):
            pass

        @property
        def save_routes_flows(self):
            return self._cy_solver.save_routes_flows

        @save_routes_flows.setter
        def save_routes_flows(self, value):
            self._cy_solver.save_routes_flows = value

        @property
        def routes(self):
            return self._cy_solver.routes

        @property
        def routes_flows_array(self):
            return self._cy_solver.route_flows_arr

        @property
        def stats(self):
            return self._cy_solver.stats
    solver_registry.append(CythonLPSolveSolver)
