"""Source module to create ``Policy`` space from.
This module is a source module to create ``Policy`` space and its
sub spaces from.
The formulas of the cells in the ``Policy`` space are created from the
functions defined in this module.
The ``Policy`` space is the base space of the policy spaces
for individual policies, which are derived from and belong to
the ``Policy`` space as its dynamic child spaces.
The policy spaces for individual policies are parametrized by ``PolicyID``.
For example, to get the policy space of the policy whose ID is 171::
    >> pol = model.Policy(171)
The cells in a policy space for each individual policy retrieve
input data, calculate and hold values of policy attributes specific to that policy,
so various spaces in :mod:`Input<simplelife.build_input>` must be accessible
from the ``Policy`` space.
.. rubric:: Project Templates
This module is included in the following project templates.
* :mod:`simplelife`
* :mod:`nestedlife`
.. rubric:: Space Parameters
Attributes:
    PolicyID: Policy ID
.. rubric:: References in Base
Attributes:
    PolicyData: Input.PolicyData
    ProductSpec: Input.ProductSpec
    LifeTable: LifeTable
    Gen: Generation key
.. rubric:: References in Sub
Attributes:
    Product: Product key
    PolicyType: Policy type key
    Gen: Generation key
    Channel: Channel key
    Sex: ``M`` for Male, ``F`` for Female
    Duration: Number of years lapsed. 0 for new business
    IssueAge: Issue age
    PremFreq: Number of premium payments per year. 12 for monthly payments
    PolicyTerm: Policy term in year
    PolicyCount: Number of policies
    SumAssured: Sum Assured per policy
"""
# Policy Attributes
policy_attrs = ['Product',
                'PolicyType',
                'Gen',
                'Channel',
                'Sex',
                'Duration',
                'IssueAge',
                # 'WholeTermPaymentFlag',
                # 'PremTerm',
                # 'PremMode',
                'PremFreq',
                # 'WholeLifeFlag',
                'PolicyTerm',
                # 'MaxTerm',
                'PolicyCount',
                'SumAssured']
                # 'GrossPremMult']
[docs]def IntRate(RateBasis):
    """Interest Rate"""
    if RateBasis == 'PREM':
        int_rate = ProductSpec.IntRatePrem
    elif RateBasis == 'VAL':
        int_rate = ProductSpec.IntRateVal
    else:
        raise ValueError('invalid RateBasis')
    result = int_rate.match(Product, PolicyType, Gen).value
    if result is not None:
        return result
    else:
        raise ValueError('invalid RateBais') 
[docs]def TableID(RateBasis):
    """Mortality Table ID"""
    if RateBasis == 'PREM':
        mort_table = ProductSpec.MortTablePrem
    elif RateBasis == 'VAL':
        mort_table = ProductSpec.MortTableVal
    else:
        raise ValueError('invalid RateBasis')
    result = mort_table.match(Product, PolicyType, Gen).value
    if result is not None:
        return result
    else:
        raise ValueError('invalid RateBais') 
[docs]def LoadAcqSA():
    """Acquisition Loading per Sum Assured"""
    param1 = ProductSpec.LoadAcqSAParam1(Product)
    param2 = ProductSpec.LoadAcqSAParam2(Product)
    return param1 + param2 * min(PolicyTerm / 10, 1) 
[docs]def LoadMaintPrem():
    """Maintenance Loading per Gross Premium"""
    if ProductSpec.LoadMaintPremParam1(Product) is not None:
        return ProductSpec.LoadMaintPremParam1(Product)
    elif ProductSpec.LoadMaintPremParam2(Product) is not None:
        param = ProductSpec.LoadMaintPremParam2(Product)
        return (param + min(10, PolicyTerm)) / 100
    else:
        raise ValueError('LoadMaintPrem parameters not found') 
[docs]def LoadMaintPremWaiverPrem():
    """Maintenance Loading per Gross Premium for Premium Waiver"""
    if PremTerm < 5:
        return 0.0005
    elif PremTerm < 10:
        return 0.001
    else:
        return 0.002 
[docs]def LoadMaintSA():
    """Maintenance Loading per Sum Assured during Premium Payment"""
    result = ProductSpec.LoadMaintSA.match(Product, PolicyType, Gen).value
    if result is not None:
        return result
    else:
        raise ValueError('lookup failed') 
[docs]def LoadMaintSA2():
    """Maintenance Loading per Sum Assured after Premium Payment"""
    result = ProductSpec.LoadMaintSA2.match(Product, PolicyType, Gen).value
    if result is not None:
        return result
    else:
        raise ValueError('lookup failed') 
[docs]def InitSurrCharge():
    """Initial Surrender Charge Rate"""
    param1 = ProductSpec.SurrChargeParam1.match(Product, PolicyType, Gen).value
    param2 = ProductSpec.SurrChargeParam2.match(Product, PolicyType, Gen).value
    if param1 is None or param2 is None:
        raise ValueError('SurrChargeParam not found')
    return param1 + param2 * min(PolicyTerm / 10, 1) 
[docs]def NetPremRate(basis):
    """Net Premium Rate"""
    gamma2 = LoadMaintSA2
    comf = LifeTable[Sex, IntRate(basis), TableID(basis)]
    if Product == 'TERM' or Product == 'WL':
        return (comf.Axn(x, n) + gamma2 * comf.AnnDuenx(x, n-m, 1, m)) / comf.AnnDuenx(x, n)
    elif Product == 'ENDW':
        return (comf.Axn(x, n) + gamma2 * comf.AnnDuenx(x, n-m, 1, m)) / comf.AnnDuenx(x, n)
    else:
        raise ValueError('invalid product') 
[docs]def GrossPremRate():
    """Gross Premium Rate per Sum Assured per payment"""
    alpha = LoadAcqSA
    beta = LoadMaintPrem
    gamma = LoadMaintSA
    gamma2 = LoadMaintSA2
    delta = LoadMaintPremWaiverPrem
    comf = LifeTable[Sex, IntRate('PREM'), TableID('PREM')]
    if Product == 'TERM' or Product == 'WL':
        return (comf.Axn(x, n) + alpha + gamma * comf.AnnDuenx(x, n, PremFreq)
                + gamma2 * comf.AnnDuenx(x, n-m, 1, m)) / (1-beta-delta) / PremFreq / comf.AnnDuenx(x, m, PremFreq)
    elif Product == 'ENDW':
        return (comf.Exn(x, n) + comf.Axn(x, n) + alpha + gamma * comf.AnnDuenx(x, n, PremFreq)
                + gamma2 * comf.AnnDuenx(x, n-m, 1, m)) / (1-beta-delta) / PremFreq / comf.AnnDuenx(x, m, PremFreq)
    else:
        raise ValueError('invalid product') 
[docs]def AnnPremRate():
    """Annualized Premium Rate per Sum Assured"""
    return GrossPremRate * (1/10 if PremFreq == 0 else PremFreq) 
[docs]def GrossPremTable():
    """Gross premium table"""
    return None 
[docs]def ReserveNLP_Rate(basis, t):
    """Net level premium reserve rate"""
    gamma2 = LoadMaintSA2
    lt = LifeTable[Sex, IntRate(basis), TableID(basis)]
    if t <= m:
        return lt.Axn(x+t, n-t) + gamma2 * lt.AnnDuenx(x+t, n-m, 1, m-t) \
                
- NetPremRate(basis) * lt.AnnDuenx(x+t, m-t)
    else:
        return lt.Axn(x+t, n-t) + gamma2 * lt.AnnDuenx(x+t, n-m, 1, m-t) 
[docs]def ReserveRate():
    """Valuation Reserve Rate per Sum Assured"""
    return None 
[docs]def SurrCharge(t):
    """Surrender Charge Rate per Sum Assured"""
    return InitSurrCharge * max((min(m, 10) - t) / min(m, 10), 0) 
[docs]def CashValueRate(t):
    """Cash Value Rate per Sum Assured"""
    return max(ReserveNLP_Rate('PREM', t) - SurrCharge(t), 0) 
[docs]def UernPremRate():
    """Unearned Premium Rate"""
    return None