#All Rights Reserved John Salguero
#Generates steps depending on the problem

import algebraic_steps
from sympy import *
from sympy.parsing.sympy_parser import (
    parse_expr,
    standard_transformations,
    implicit_multiplication_application
)
transformations = standard_transformations + (implicit_multiplication_application,)

STEP_GENERATORS = {}

def register_steps_generator(problem_type):
    def decorator(func):
        STEP_GENERATORS[problem_type] = func
        return func
    return decorator
    
@register_steps_generator("linear")
def generate_linear_steps(problem):
    #ax + b = c
    steps = []
    
    x = symbols('x')
    current = problem["problem"]
    left, right = current.split("=")
    expr = parse_expr(left)
    a = expr.coeff(x)
    b = expr.subs(x, 0)
    
    ## First Step
    if b.is_zero == False:
        if b.is_negative:
            steps.append(algebraic_steps.add_both_sides(current, -b))
        elif b.is_positive:
            steps.append(algebraic_steps.subtract_both_sides(current, b))
        current = steps[-1]["after"]
    ## Second Step    
    if a != 1 and a != -1:
        steps.append(algebraic_steps.divide_both_sides(current, a))
    elif a == -1:
        steps.append(algebraic_steps.multiply_both_sides(current, a))
    
    return steps
    
@register_steps_generator("hidden_factor")
def generate_hidden_factor_steps(problem):
    #a(x + b) + c(x + b) = d 
    steps = []
    
    x = symbols('x')
    current = problem["problem"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations, evaluate=False)
    right_expr = parse_expr(right)
    terms = left_expr.as_ordered_terms()
    #factors = [term.as_ordered_factors() for term in terms]
    #common = set(factors[0]) & set(factors[1])
    #base = list(common)[0]
    base = terms[0].args[1]
    
    ## First Step
    steps.append(algebraic_steps.factor_collect(current))
    current = steps[-1]["after"]
    
    ## Second Step
    div = simplify(left_expr / base)
    steps.append(algebraic_steps.divide_both_sides(current, div))
    current = steps[-1]["after"]
    
    ## Third Step
    b = base.subs(x, 0)
    if b.is_negative:
        steps.append(algebraic_steps.add_both_sides(current, -b))
    elif b.is_positive:
        steps.append(algebraic_steps.subtract_both_sides(current, b))
    
    current = steps[-1]["after"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    right_expr = parse_expr(right)
    steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
    
    return steps
    

@register_steps_generator("distribution")
def generate_distribution_steps (problem):
    #a(x + b) = c
    steps = []
    
    x = symbols('x')
    current = problem["problem"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations, evaluate=False)
    right_expr = parse_expr(right)
    terms = left_expr.as_ordered_terms()
    base = terms[0].args[1]
    div = simplify(left_expr / base)
    
    ## First Step
    steps.append(algebraic_steps.divide_both_sides(current, div))
    current = steps[-1]["after"]
    
    ## Second Step
    b = base.subs(x, 0)
    if b.is_negative:
        steps.append(algebraic_steps.add_both_sides(current, -b))
    elif b.is_positive:
        steps.append(algebraic_steps.subtract_both_sides(current, b))
    
    current = steps[-1]["after"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    right_expr = parse_expr(right)
    steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
    
    return steps
    
@register_steps_generator("two_sides")
def generate_two_sides_steps (problem):
    #ax + b = dx + e : a != d
    steps = []
    
    x = symbols('x')
    current = problem["problem"]
    left, right = current.split("=")
    left_expr = parse_expr(left)
    right_expr = parse_expr(right)
    a = left_expr.coeff(x)
    b = left_expr.subs(x, 0)
    d = right_expr.coeff(x)
    e = right_expr.subs(x, 0)
    
    ## First Step
    if d.is_negative:
        steps.append(algebraic_steps.add_both_sides(current, -d*x))
    elif d.is_positive:
        steps.append(algebraic_steps.subtract_both_sides(current, d*x))
    current = steps[-1]["after"]
    left, right = current.split("=")
    left_expr = parse_expr(left)
    right_expr = parse_expr(right)
    steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
    current = steps[-1]["after"]
    
    ## Second Step
    if b.is_negative:
        steps.append(algebraic_steps.add_both_sides(current, -b))
    elif b.is_positive:
        steps.append(algebraic_steps.subtract_both_sides(current, b))
    current = steps[-1]["after"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    right_expr = parse_expr(right)
    steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
    current = steps[-1]["after"]
    
    ## Third Step
    new_left, new_right = current.split("=")
    new_left_expr = parse_expr(left, transformations=transformations, evaluate=False)
    new_right_expr = parse_expr(right, transformations=transformations, evaluate=False)
    div = left_expr.coeff(x)
    if div != 1 and div != -1:
        steps.append(algebraic_steps.divide_both_sides(current, div))
    elif div == -1:
        steps.append(algebraic_steps.multiply_both_sides(current, div))
    
    return steps
    
@register_steps_generator("like_terms")
def generate_like_terms_steps (problem):
    #ax + bx + c = d
    steps = []
    
    x = symbols('x')
    current = problem["problem"]
    
    ## First Step
    steps.append(algebraic_steps.combine_like_terms(current))
    current = steps[-1]["after"]
    
    ## Second Step
    left, right = current.split("=")
    left_expr = parse_expr(left)
    b = left_expr.subs(x, 0)
    if b.is_negative:
        steps.append(algebraic_steps.add_both_sides(current, -b))
    elif b.is_positive:
        steps.append(algebraic_steps.subtract_both_sides(current, b))
    current = steps[-1]["after"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    right_expr = parse_expr(right)
    steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
    current = steps[-1]["after"]
    
    ## Third Step
    div = left_expr.coeff(x)
    if div != 1 and div != -1:
        steps.append(algebraic_steps.divide_both_sides(current, div))
    elif div == -1:
        steps.append(algebraic_steps.multiply_both_sides(current, div))
    
    return steps
    
@register_steps_generator("quadratic")
def generate_quadratic_steps (problem):
    #ax² + bx + c = 0
    steps = []
    
    x = symbols('x')
    current = problem["problem"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    right_expr = parse_expr(right)
    a = left_expr.coeff(x**2)
    b = left_expr.coeff(x)
    c = left_expr.subs(x, 0)
    div = gcd(a, b, c)
    if a.is_negative:
        div = -div
    
    ## First Step
    if div != 1 and c.is_zero == False:
        steps.append(algebraic_steps.factor_out(current, div))
        current = steps[-1]["after"]
    elif c.is_zero:
        div = gcd(a, b)
        steps.append(algebraic_steps.factor_out(current, div*x))
        current = steps[-1]["after"]
    
    if c.is_zero == False:
        ## Second Steps
        left, right = current.split("=")
        left_expr = parse_expr(left, transformations=transformations)
        inner = left_expr / div
        steps.extend(algebraic_steps.trinomial_by_grouping(current,inner))
        current = steps[-1]["after"]
    
    ##Solve the Roots
    steps.extend(algebraic_steps.solve_roots(current))
    current = steps[-1]["after"]
    
    # Check for incorrect answers
    steps.extend(algebraic_steps.check_roots(problem["problem"], current))
    
    return steps
    
@register_steps_generator("difference_squares")
def generate_difference_squares_steps (problem):
    #x² - a² = 0
    steps = []
    
    x = symbols('x')
    current = problem["problem"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    b = left_expr.subs(x, 0)
    
    ## Step 1
    if b.is_negative:
        steps.append(algebraic_steps.add_both_sides(current, -b))
    elif b.is_positive:
        steps.append(algebraic_steps.subtract_both_sides(current, b))
    current = steps[-1]["after"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    right_expr = parse_expr(right)
    steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
    current = steps[-1]["after"]
    
    ## Step 2
    steps.append(algebraic_steps.square_root_both_sides(current))
    current = steps[-1]["after"]
    
    # Check for incorrect answers
    steps.extend(algebraic_steps.check_roots(problem["problem"], current))
    
    return steps
    
@register_steps_generator("zero_product")
def generate_zero_product_steps (problem):
    #(x + a)(x + b) = 0
    steps = []
    current = problem["problem"]
    
    steps.extend(algebraic_steps.solve_roots(current))
    
    return steps
    
@register_steps_generator("radical")
def generate_radical_steps (problem):
    #√(x + a) = b
    steps = []
    x = symbols('x')
    current = problem["problem"]
    
    
    ## First Step
    steps.append(algebraic_steps.square_both_sides(current))
    
    ## Second Step
    current = steps[-1]["after"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    b = left_expr.subs(x, 0)
    if b.is_zero != False:
        if b.is_negative:
            steps.append(algebraic_steps.add_both_sides(current, -b))
        elif b.is_positive:
            steps.append(algebraic_steps.subtract_both_sides(current, b))
        current = steps[-1]["after"]
        left, right = current.split("=")
        left_expr = parse_expr(left, transformations=transformations)
        right_expr = parse_expr(right)
        steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
        
    current = steps[-1]["after"]
    
    # Check for incorrect answers
    steps.extend(algebraic_steps.check_roots(problem["problem"], current))
    
    return steps
    
@register_steps_generator("fraction")
def generate_fraction_steps (problem):
    #(x/a) + b = c
    steps = []
    x = symbols('x')
    current = problem["problem"]
    
    ## First Step
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    b = left_expr.subs(x, 0)
    if b.is_zero == False:
        if b.is_negative:
            steps.append(algebraic_steps.add_both_sides(current, -b))
        elif b.is_positive:
            steps.append(algebraic_steps.subtract_both_sides(current, b))
        current = steps[-1]["after"]
        left, right = current.split("=")
        left_expr = parse_expr(left, transformations=transformations)
        right_expr = parse_expr(right)
        steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
        current = steps[-1]["after"]
    
    ## Second step
    num, den = fraction(left_expr)
    if left_expr.subs(x,1).is_negative:
        steps.append(algebraic_steps.multiply_both_sides(current, -den))
    else:
        steps.append(algebraic_steps.multiply_both_sides(current, den))
    
    return steps
    
@register_steps_generator("binomial")
def generate_binomial_steps (problem):
    #a(x + b) + c(x + d) = e
    steps = []
    x = symbols('x')
    current = problem["problem"]
    
    ## Distribute Terms
    init_printing(order='none')
    last_len = -1
    while last_len != len(steps):
        last_len = len(steps)
        steps.extend(algebraic_steps.distribute_left_step(current))
        if len(steps):
            current = steps[-1]["after"]
    init_printing(order='lex')
    
    ## Combine Like Terms
    steps.append(algebraic_steps.combine_like_terms(current))
    current = steps[-1]["after"]
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    
    ## Subtract constant
    b = left_expr.subs(x, 0)
    if b.is_zero == False:
        if b.is_negative:
            steps.append(algebraic_steps.add_both_sides(current, -b))
        elif b.is_positive:
            steps.append(algebraic_steps.subtract_both_sides(current, b))
        current = steps[-1]["after"]
        left, right = current.split("=")
        left_expr = parse_expr(left, transformations=transformations)
        right_expr = parse_expr(right)
        steps[-1]["after"] = f"{sstr(left_expr)} = {sstr(right_expr)}"
        current = steps[-1]["after"]
    
    ## Divide by coefficient
    a = left_expr.coeff(x)
    if a != 1 and a != -1:
        steps.append(algebraic_steps.divide_both_sides(current, a))
    elif a == -1:
        steps.append(algebraic_steps.multiply_both_sides(current, a))
    
    return steps
    
@register_steps_generator("tricky")
def generate_tricky_steps (problem):
    #(x² - x - a) / (x + b) = c
    steps = []
    x = symbols('x')
    current = problem["problem"]
    
    # Multiply Denom
    left, right = current.split("=")
    left_expr = parse_expr(left, transformations=transformations)
    right_expr = parse_expr(right)
    num, den = left_expr.as_numer_denom()
    steps.append(algebraic_steps.multiply_both_sides(current, den))
    current = steps[-1]["after"]
    
    # Distribute out right side
    init_printing(order='none')
    steps.extend(algebraic_steps.distribute_right_step(current))
    current = steps[-1]["after"]
    init_printing(order='lex')
    
    # Move Everything to Left
    steps.append(algebraic_steps.move_all_to_one_side(current))
    current = steps[-1]["after"]
    
    # Combine Like Terms
    steps.append(algebraic_steps.combine_like_terms(current))
    current = steps[-1]["after"]
    
    # Solve Quadratic
    print(f"calling generate_quadratic_steps with: {current}")
    steps.extend(generate_quadratic_steps({"problem" : current}))
    current = steps[-1]["after"]
    
    # Check for incorrect answers
    steps.extend(algebraic_steps.check_roots(problem["problem"], current))
    
    return steps
    
def generate_steps(problem):
    problem_type = problem["type"]
    
    if problem_type not in STEP_GENERATORS:
        raise ValueError(f"No step generator for type: {problem_type}")
    
    return STEP_GENERATORS[problem["type"]](problem)