"""Simple water flow example using ANUGA

Water flowing down a channel with more complex topography
"""

#------------------------------------------------------------------------------
# Import necessary modules
#------------------------------------------------------------------------------
from anuga.abstract_2d_finite_volumes.mesh_factory import rectangular_cross
from anuga.abstract_2d_finite_volumes.util import file_function
from anuga.shallow_water import Domain
from anuga.shallow_water import Reflective_boundary
from anuga.shallow_water import Dirichlet_boundary
from anuga.shallow_water import Time_boundary
from anuga.shallow_water import Field_boundary
from anuga.shallow_water.shallow_water_domain import Inflow


#------------------------------------------------------------------------------
# Setup computational domain
#------------------------------------------------------------------------------
length = 40.
width = 5.
dx = dy = .1           # Resolution: Length of subdivisions on both axes
#dx = dy = .1           # Resolution: Length of subdivisions on both axes

points, vertices, boundary = rectangular_cross(int(length/dx), int(width/dy),
                                               len1=length, len2=width)
domain = Domain(points, vertices, boundary)   
domain.set_name('hydro_example')                  # Output name
domain.set_minimum_storable_height(0.0001)
domain.beta_h = 0.0
domain.limit2007 = 1


#------------------------------------------------------------------------------
# Setup initial conditions
#------------------------------------------------------------------------------
def topography(x,y):
    """Complex topography defined by a function of vectors x and y
    """
    
    z = -x/10
    #z = x*0.0

    N = len(x)
    for i in range(N):

        #Step
        if 10 < x[i] < 12:
            z[i] += 0.4 - 0.05*y[i]        
        
        #Constriction
        if 27 < x[i] < 29 and y[i] > 3:
            z[i] += 2        
        
        # Pole
        if (x[i] - 34)**2 + (y[i] - 2)**2 < 0.4**2:
            z[i] += 2

    return z


domain.set_quantity('elevation', topography)  # Use function for elevation
domain.set_quantity('friction', 0.01)         # Constant friction 
domain.set_quantity('stage',
                    expression='elevation')   # Dry initial condition


#------------------------------------------------------------------------------
# Setup specialised forcing terms
#------------------------------------------------------------------------------

#hydrograph = Inflow(center=(1.0, 0.5*width), radius=1.0,
#	     flow=lambda t: min(0.01*t, 0.0142)) # Tap turning up  	

hydrograph = Inflow(center=(1.0, 0.5*width), radius=1.0,
	     flow=file_function('Island_Pt_Rd_Meta.tms'))

domain.forcing_terms.append(hydrograph)


#------------------------------------------------------------------------------
# Setup boundary conditions
#------------------------------------------------------------------------------

#Hydrograph = Field_boundary('Island_Pt_Rd_Meta.tms', domain,
#                            mean_stage=0.01)
                 
Bi = Dirichlet_boundary([0.4, 0, 0])          # Inflow
Br = Reflective_boundary(domain)              # Solid reflective wall
Bo = Dirichlet_boundary([-5, 0, 0])           # Outflow

domain.set_boundary({'left': Br,
                     'right': Br,
                     'top': Br,
                     'bottom': Br})


#------------------------------------------------------------------------------
# Evolve system through time
#------------------------------------------------------------------------------
domain.start_time = 2800
for t in domain.evolve(yieldstep = 1, finaltime = 32700):
    domain.write_time()


    #if domain.get_quantity('stage').\
    #       get_values(interpolation_points=[[10, 2.5]]) > 0:        
    #    print 'Stage > 0: Changing to outflow boundary'
    #    domain.set_boundary({'right': Bo})