def get_sector_yfinance(ticker_symbol):
    """Fetch the sector for a given ticker using yfinance."""
    ticker = yf.Ticker(ticker_symbol)
    info = ticker.info
    return info.get('sector', None)

def get_industry_yfinance(ticker_symbol):
    """Fetch the sector for a given ticker using yfinance."""
    ticker = yf.Ticker(ticker_symbol)
    info = ticker.info
    return info.get('sector', None)

def get_stocks_from_same_industry(ticker_symbol):
    """Fetch stocks from the same industry as the provided ticker."""
    # Get the sector for the given ticker using yfinance
    sector = get_industry_yfinance(ticker_symbol)

    if not sector:
        print(f"Could not find industry for {ticker_symbol}")
        return None

    # Initialize the screener from yahooquery
    s = Screener()

    # Using sector to screen stocks
    screen_key = f"ms_{sector.lower()}"

    if screen_key not in s.available_screeners:
        print(f"No predefined screener available for sector: {sector}")
        return None

    data = s.get_screeners(screen_key)

    # Convert data to DataFrame for easier handling
    df = pd.DataFrame(data[screen_key]['quotes'])

    return df

def calculate_rolling_beta(stock_data, market_data, window_size):
    stock_returns = stock_data['Adj Close'].pct_change().dropna()
    market_returns = market_data['Adj Close'].pct_change().dropna()

    rolling_cov = stock_returns.rolling(window=window_size).cov(market_returns)
    rolling_var = market_returns.rolling(window=window_size).var()

    rolling_beta = rolling_cov / rolling_var
    return rolling_beta.dropna()

def get_unlevered_beta(ticker):
    stock = yf.Ticker(ticker)

    # Get levered beta
    levered_beta = stock.info['beta']
    if not levered_beta:
        return None

    # Get debt and equity values
    market_cap = stock.info['marketCap'] / 10**9
    long_term_debt = stock.balance_sheet.loc["Long Term Debt"][0] / 10**9 if "Long Term Debt" in stock.balance_sheet.index else 0
    short_term_debt = stock.balance_sheet.loc["Short Term Debt"][0] / 10**9 if "Short Term Debt" in stock.balance_sheet.index else 0
    debt_value = long_term_debt + short_term_debt
    equity_value = market_cap

    # Calculate the effective tax rate
    income_statement = stock.financials
    pretax_income = float(income_statement.loc["Pretax Income"].iloc[0])
    income_tax_expense = float(income_statement.loc["Tax Provision"].iloc[0])
    effective_tax_rate = income_tax_expense / pretax_income
    T = effective_tax_rate

    # Calculate unlevered beta
    return levered_beta / (1 + ((1 - T) * (debt_value / equity_value)))


def get_pretax_cost_of_debt(ticker):
    """Compute the pre-tax cost of debt for a given ticker."""
    stock = yf.Ticker(ticker)

    income_statement = stock.financials
    balance_sheet = stock.balance_sheet

    # Interest Expense from the income statement
    interest_expense = float(income_statement.loc["Interest Expense"].iloc[0]) if "Interest Expense" in income_statement.index else 0

    # Average Total Debt calculation
    current_long_term_debt = float(balance_sheet.loc["Long Term Debt"].iloc[0]) if "Long Term Debt" in balance_sheet.index else 0
    previous_long_term_debt = float(balance_sheet.loc["Long Term Debt"].iloc[1]) if "Long Term Debt" in balance_sheet.index else 0

    current_short_term_debt = float(balance_sheet.loc["Short Term Debt"].iloc[0]) if "Short Term Debt" in balance_sheet.index else 0
    previous_short_term_debt = float(balance_sheet.loc["Short Term Debt"].iloc[1]) if "Short Term Debt" in balance_sheet.index else 0

    average_debt = (current_long_term_debt + current_short_term_debt + previous_long_term_debt + previous_short_term_debt) / 2

    # Calculate the pre-tax cost of debt
    if average_debt == 0:
        return 0
    else:
        return interest_expense / average_debt

def get_year_cost_of_debt_converges(ticker, comparable_tickers):
  """Compute the year when the cost of debt converges to the industry average."""
  # Get the current pre-tax cost of debt for the given ticker
  DURATION = 5
  current_pretax_cost_of_debt = get_pretax_cost_of_debt(ticker)
  if not current_pretax_cost_of_debt:
    return None # No cost of debt available

  # Get the pre-tax cost of debt for each comparable ticker
  pretax_costs_of_debt = [get_pretax_cost_of_debt(ticker) for ticker in comparable_tickers]
  pretax_costs_of_debt = [cost for cost in pretax_costs_of_debt if cost is not None] # Remove None values

  # Calculate the industry average pre-tax cost of debt
  industry_average_pretax_cost_of_debt = sum(pretax_costs_of_debt) / len(pretax_costs_of_debt)

  # Estimate the terminal pre-tax cost of debt using a weighted average
  omega = 0.5 # Weight given to the company's current pre-tax cost of debt
  terminal_pretax_cost_of_debt = omega * current_pretax_cost_of_debt + (1 - omega) * industry_average_pretax_cost_of_debt

  # Assume a linear convergence from the current to the terminal cost of debt
  # Use the equation y = mx + b, where y is the cost of debt, x is the year, m is the slope, and b is the intercept
  # Solve for x when y equals the terminal cost of debt
  slope = (terminal_pretax_cost_of_debt - current_pretax_cost_of_debt) / DURATION # DURATION is the number of years for valuation
  intercept = current_pretax_cost_of_debt
  year_cost_of_debt_converges = (terminal_pretax_cost_of_debt - intercept) / slope

  return year_cost_of_debt_converges

def get_marginal_tax_rate(ticker):
    """Compute the marginal tax rate for a given ticker using yfinance."""
    # Get the income statement from yfinance
    stock = yf.Ticker(ticker)
    income_statement = stock.financials

    # Get the income before tax and income tax expense from the income statement
    income_before_tax = float(income_statement.loc["Pretax Income"].iloc[0])
    income_tax_expense = float(income_statement.loc["Tax Provision"].iloc[0])

    # Calculate the marginal tax rate as the ratio of income tax expense to income before tax
    marginal_tax_rate = income_tax_expense / income_before_tax

    # Return the marginal tax rate as a percentage
    return marginal_tax_rate

def get_ttm_total_revenue(ticker_symbol):
    ticker = yf.Ticker(ticker_symbol)

    # Fetch the total revenue for the TTM
    ttm_revenue = ticker.info['totalRevenue']

    return ttm_revenue

# Define the URL for the API endpoint
TICKER = "AAPL"
ENDPOINT = "https://query1.finance.yahoo.com/v7/finance/download/{}"
TICKER_SP500 = "^GSPC"
DURATION = 10  # 10 years
TODAY = int(datetime.now().timestamp())
TEN_YEARS_AGO = int((datetime.now() - pd.DateOffset(years=DURATION)).timestamp())
urlRFR = "https://query1.finance.yahoo.com/v7/finance/download/%5ETNX?period1=0&period2=9999999999&interval=1d&events=history&includeAdjustedClose=true"
headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36'
}
responseRFR = requests.get(urlRFR, headers=headers)

if responseRFR.status_code == 200:
    content = responseRFR.text
    lines = content.strip().split("\n")

    if len(lines) < 2:  # Check if there's at least a header and one data line
        print("Error: Not enough data lines in the response.")
        exit()

    last_line = lines[-1]
    values = last_line.split(",")

    if len(values) < 4:  # Check if there are enough values in the last line
        print("Error: Not enough values in the data line.")
        exit()

    RFR = float(values[3])
    print(f"The 10-year treasury yield in USA is {RFR}%")
else:
    print(f"Error: The request failed with status code {responseRFR.status_code}. Response: {responseRFR.text}")


# Fetch S&P 500 historical data
urlSP500 = ENDPOINT.format(TICKER_SP500) + f"?period1={TEN_YEARS_AGO}&period2={TODAY}&interval=1d&events=history&includeAdjustedClose=true"
responseSP500 = requests.get(urlSP500, headers=headers)
if responseSP500.status_code != 200:
    raise Exception("Error fetching S&P 500 data.")
dataSP500 = pd.read_csv(urlSP500, parse_dates=['Date'], index_col='Date')

urlCOMPANY = ENDPOINT.format(TICKER) + f"?period1={TEN_YEARS_AGO}&period2={TODAY}&interval=1d&events=history&includeAdjustedClose=true"
responseCOMPANY = requests.get(urlCOMPANY, headers=headers)
if responseCOMPANY.status_code != 200:
    raise Exception("Error fetching company data.")
dataCOMPANY = pd.read_csv(io.StringIO(responseCOMPANY.text), parse_dates=['Date'], index_col='Date')

historical_beta = calculate_rolling_beta(dataCOMPANY, dataSP500, 252)

# Calculate annualized return for S&P 500 over the given duration
initial_value = dataSP500['Adj Close'].iloc[0]
final_value = dataSP500['Adj Close'].iloc[-1]
Rm = ((final_value / initial_value) ** (1/DURATION) - 1)
risk_free_rate = RFR/100
ERP = Rm - risk_free_rate
print(f"Equity Risk Premium: {ERP*100:.2f}%")

# Use yfinance to get the market capitalization
stock = yf.Ticker(TICKER)
market_cap = stock.info['marketCap'] / 10**9  # Convert to billions

equity_value = market_cap
print(f"The equity value (market cap) of {TICKER} is approximately ${market_cap:.2f} billion.")

# Use yfinance to get the debt values
long_term_debt = stock.balance_sheet.loc["Long Term Debt"][0] if "Long Term Debt" in stock.balance_sheet.index else 0
short_term_debt = stock.balance_sheet.loc["Short Term Debt"][0] if "Short Term Debt" in stock.balance_sheet.index else 0

# Calculate total debt
debt_value = (long_term_debt + short_term_debt) / 10**9  # Convert to billions
print(f"The total debt of {TICKER} is approximately ${debt_value:.2f} billion.")

# Use yfinance to get the cash and non-operating asset values
cash_and_cash_equivalents = stock.balance_sheet.loc["Cash And Cash Equivalents"][0] if "Cash And Cash Equivalents" in stock.balance_sheet.index else 0
# Convert to billions
cash_and_non_operating_asset = cash_and_cash_equivalents / 10**9
print(f"Cash and non-operating assets of {TICKER} is approximately ${cash_and_non_operating_asset:.2f} billion.")


df_result = get_stocks_from_same_industry(TICKER)
comparable_tickers = df_result['symbol'].tolist()

print(comparable_tickers)
# Get unlevered betas for each comparable
unlevered_betas = [get_unlevered_beta(ticker) for ticker in comparable_tickers]
unlevered_betas = [beta for beta in unlevered_betas if beta is not None]  # Remove None values
# Calculate the industry average unlevered beta
industry_average_unlevered_beta = sum(unlevered_betas) / len(unlevered_betas)

# Estimate the terminal_unlevered_beta
omega = 0.5  # Weight given to the company's current unlevered beta
unlevered_beta = get_unlevered_beta(TICKER)
terminal_unlevered_beta = omega * unlevered_beta + (1 - omega) * industry_average_unlevered_beta

print(f"The estimated unlevered beta is: {unlevered_beta:.4f}")
print(f"The estimated terminal unlevered beta is: {terminal_unlevered_beta:.4f}")

# Linear regression model
X = np.array(range(len(historical_beta))).reshape(-1, 1)
y = historical_beta.values
model = LinearRegression().fit(X, y)
slope = model.coef_
intercept = model.intercept_

# Calculate the intersection point with terminal beta using the equation of the line
# y = mx + c; terminal_beta = slope*x + intercept
intersection_point = (terminal_unlevered_beta - intercept) / slope

# Convert intersection_point to years (assuming your historical data is daily)
intersection_in_years = intersection_point[0] / 252  # 252 trading days in a year

print(f"Expected year to converge to terminal beta: {intersection_in_years:.2f} years")

year_beta_begins_to_converge_to_terminal_beta = intersection_in_years

# Calculate the effective tax rate
income_statement = stock.financials
pretax_income = float(income_statement.loc["Pretax Income"].iloc[0])
income_tax_expense = float(income_statement.loc["Tax Provision"].iloc[0])
tax_rate = income_tax_expense / pretax_income

print(f"Current Effective Tax Rate: {tax_rate:.2%}")

current_effective_tax_rate = tax_rate

current_pretax_cost_of_debt = get_pretax_cost_of_debt(TICKER)

print(f"Current Pretax Cost of Debt: {current_pretax_cost_of_debt:.2%}")

# Get pre-tax cost of debt for each comparable
pretax_costs_of_debt = [get_pretax_cost_of_debt(ticker) for ticker in comparable_tickers]
pretax_costs_of_debt = [cost for cost in pretax_costs_of_debt if cost is not None]

# Calculate the industry average pre-tax cost of debt
industry_average_pretax_cost_of_debt = sum(pretax_costs_of_debt) / len(pretax_costs_of_debt)

# Estimate the terminal_pre_tax_cost_of_debt
omega = 0.5  # Weight given to the company's current pre-tax cost of debt
terminal_pretax_cost_of_debt = omega * current_pretax_cost_of_debt + (1 - omega) * industry_average_pretax_cost_of_debt

print(f"The estimated terminal pre-tax cost of debt is: {terminal_pretax_cost_of_debt:.2%}")

year_cost_of_debt_begins_to_converge_to_terminal_cost_of_debt = get_year_cost_of_debt_converges(TICKER, comparable_tickers)

print(f"Expected year to converge to the cost of debt: {year_cost_of_debt_begins_to_converge_to_terminal_cost_of_debt:.2f} years")

marginal_tax_rate = get_marginal_tax_rate(TICKER)

print(f"Current Marginal Tax Rate: {marginal_tax_rate:.2%}")

year_effective_tax_rate_begin_to_converge_marginal_tax_rate = 1

revenue_base = get_ttm_total_revenue(TICKER)

print(f"The total revenue of {TICKER} is approximately ${revenue_base}")

base_case_valuation = valuator_multi_phase(
            risk_free_rate,
            ERP,
            equity_value,
            debt_value,
            cash_and_non_operating_asset,
            unlevered_beta,
            terminal_unlevered_beta,
            year_beta_begins_to_converge_to_terminal_beta,
            current_pretax_cost_of_debt,
            terminal_pretax_cost_of_debt,
            year_cost_of_debt_begins_to_converge_to_terminal_cost_of_debt,
            current_effective_tax_rate,
            marginal_tax_rate,
            year_effective_tax_rate_begin_to_converge_marginal_tax_rate,
             revenue_base,
             revenue_growth_rate_cycle1_begin = .11,
             revenue_growth_rate_cycle1_end = .16,
             length_of_cylcle1 = 6,
             revenue_growth_rate_cycle2_begin = .14,
             revenue_growth_rate_cycle2_end = .09,
             length_of_cylcle2=6,
             revenue_growth_rate_cycle3_begin =.08,
             revenue_growth_rate_cycle3_end =.04,
             length_of_cylcle3=6,
            revenue_convergance_periods_cycle1= 1,
            revenue_convergance_periods_cycle2=1,
            revenue_convergance_periods_cycle3=1,
            current_sales_to_capital_ratio = 1.7,
            terminal_sales_to_capital_ratio = 1.3,
            year_sales_to_capital_begins_to_converge_to_terminal_sales_to_capital = 1,
            current_operating_margin = .15,
            terminal_operating_margin = .175,
            year_operating_margin_begins_to_converge_to_terminal_operating_margin = 1,
            additional_return_on_cost_of_capital_in_perpetuity= 0.02,
            asset_liquidation_during_negative_growth=0,
            current_invested_capital = 6.062)
point_estimate_describer(base_case_valuation)