import pandas as pd
import gradio as gr
from fpdf import FPDF
from fpdf import enums
import tempfile
import os
import matplotlib.pyplot as plt
import matplotlib.dates as mdates


# --- PDF Generation Helper Function (Unchanged) ---
def create_pdf_report(text_content):
    """
    Generates a PDF file from a given text string.
    """
    try:
        temp_dir = tempfile.gettempdir()
        pdf_path = os.path.join(
            temp_dir, next(tempfile._get_candidate_names()) + ".pdf"
        )

        pdf = FPDF()
        pdf.add_page()

        pdf.set_font("Courier", size=10)

        pdf.set_font("Courier", "B", 16)
        pdf.cell(
            0,
            10,
            "SaaS Metrics Analysis Report",
            0,
            new_x=enums.XPos.LMARGIN,
            new_y=enums.YPos.NEXT,
        )
        pdf.ln(10)

        pdf.set_font("Courier", size=10)

        encoded_text = text_content.encode("latin-1", "replace").decode("latin-1")
        pdf.multi_cell(0, 5, text=encoded_text)

        pdf.output(pdf_path)

        return pdf_path
    except Exception as e:
        print(f"Error creating PDF: {e}")
        return None


# --- Visualization Helper Function ---
def create_visualizations(df):
    """
    Generates matplotlib plots from the dataframe.
    """
    try:
        # Ensure plots are closed to prevent memory issues in long-running apps
        plt.close("all")

        # --- Plot 1: MRR Trend ---
        fig1, ax1 = plt.subplots(figsize=(10, 5))
        ax1.plot(df["Date"], df["MRR_End"], marker="o", linestyle="-", color="#1E88E5")
        ax1.set_title("Monthly Recurring Revenue (MRR) Trend", fontsize=14)
        ax1.set_xlabel("Date", fontsize=12)
        ax1.set_ylabel("MRR ($)", fontsize=12)
        ax1.grid(True, which="both", linestyle="--", linewidth=0.5)
        ax1.xaxis.set_major_formatter(mdates.DateFormatter("%Y-%m"))
        ax1.tick_params(axis="x", rotation=45)
        fig1.tight_layout()

        # --- Plot 2: Customer Growth ---
        fig2, ax2 = plt.subplots(figsize=(10, 5))
        ax2.plot(
            df["Date"],
            df["Total_Customers_End"],
            marker="o",
            linestyle="-",
            color="#43A047",
        )
        ax2.set_title("Customer Growth Trend", fontsize=14)
        ax2.set_xlabel("Date", fontsize=12)
        ax2.set_ylabel("Total Customers", fontsize=12)
        ax2.grid(True, which="both", linestyle="--", linewidth=0.5)
        ax2.xaxis.set_major_formatter(mdates.DateFormatter("%Y-%m"))
        ax2.tick_params(axis="x", rotation=45)
        fig2.tight_layout()

        # --- Plot 3: LTV vs CAC (Last Month) ---
        last_month = df.iloc[-1]
        mrr_now = last_month["MRR_End"]
        active_accounts = last_month["Total_Customers_End"]
        arpa_monthly = calculate_arpa(mrr_now, active_accounts)
        # customer_churn_rate_monthly = calculate_customer_churn_rate(
        #     last_month["Churned_Customers"], last_month["Total_Customers_Start"]
        # )
        gross_rev_churn_rate_monthly = calculate_gross_revenue_churn_rate(
            last_month["Churned_Revenue"], last_month["MRR_Start"]
        )
        gross_margin_monthly = calculate_gross_margin(
            last_month["Total_Revenue"], last_month["COGS"]
        )
        ltv = calculate_ltv(
            arpa_monthly, gross_margin_monthly, gross_rev_churn_rate_monthly
        )
        cac_monthly = calculate_cac(
            last_month["Sales_And_Marketing_Spend"], last_month["New_Customers"]
        )

        fig3, ax3 = plt.subplots(figsize=(8, 5))
        metrics = ["LTV (Lifetime Value)", "CAC (Acquisition Cost)"]
        values = [ltv, cac_monthly]
        bars = ax3.bar(metrics, values, color=["#43A047", "#E53935"])
        ax3.set_title(
            f"LTV vs. CAC for {last_month['Date'].strftime('%Y-%m')}", fontsize=14
        )
        ax3.set_ylabel("Value ($)", fontsize=12)
        # Add value labels on top of bars
        for bar in bars:
            yval = bar.get_height()
            ax3.text(
                bar.get_x() + bar.get_width() / 2.0,
                yval,
                f"${yval:,.0f}",
                va="bottom",
                ha="center",
            )
        fig3.tight_layout()

        # --- Plot 4: Net Revenue Retention (NRR) Trend ---
        # Calculate NRR for each row if it's not already there
        df["NRR"] = df.apply(
            lambda row: calculate_nrr(
                row["MRR_Start"], row["Expansion_Revenue"], row["Churned_Revenue"]
            ),
            axis=1,
        )
        fig4, ax4 = plt.subplots(figsize=(10, 5))
        ax4.plot(df["Date"], df["NRR"], marker="o", linestyle="-", color="#8E24AA")
        ax4.axhline(y=1.0, color="grey", linestyle="--", label="100% Benchmark")
        ax4.set_title("Net Revenue Retention (NRR) Trend", fontsize=14)
        ax4.set_xlabel("Date", fontsize=12)
        ax4.set_ylabel("NRR", fontsize=12)
        ax4.yaxis.set_major_formatter(plt.FuncFormatter(lambda y, _: f"{y:.0%}"))
        ax4.grid(True, which="both", linestyle="--", linewidth=0.5)
        ax4.xaxis.set_major_formatter(mdates.DateFormatter("%Y-%m"))
        ax4.tick_params(axis="x", rotation=45)
        ax4.legend()
        fig4.tight_layout()

        return fig1, fig2, fig3, fig4
    except Exception as e:
        print(f"Error creating visualizations: {e}")
        return None, None, None, None


# --- Core SaaS Metrics Functions (Unchanged) ---
def calculate_arr(mrr):
    return mrr * 12


def calculate_yoy_growth(current, prior):
    return (current - prior) / prior if prior > 0 else 0


def calculate_sde(revenue, cogs, op_ex, owner_comp):
    return revenue - cogs - op_ex + owner_comp


def calculate_valuation_revenue(arr, multiple):
    return arr * multiple


def calculate_valuation_sde(sde, multiple):
    return sde * multiple


def calculate_valuation_ebitda(ebitda, multiple):
    return ebitda * multiple


def calculate_rule_of_40(growth_percent, margin_percent):
    return growth_percent + margin_percent


def calculate_arpa(mrr, customers):
    return mrr / customers if customers > 0 else 0


def calculate_customer_churn_rate(churned, start):
    return churned / start if start > 0 else 0


def calculate_gross_revenue_churn_rate(churned_rev, mrr_start):
    return churned_rev / mrr_start if mrr_start > 0 else 0


def calculate_net_revenue_churn_rate(churned_rev, expansion_rev, mrr_start):
    return (churned_rev - expansion_rev) / mrr_start if mrr_start > 0 else 0


def calculate_nrr(mrr_start, expansion, churned):
    return (mrr_start + expansion - churned) / mrr_start if mrr_start > 0 else 0


def calculate_cac(sm_spend, new):
    return sm_spend / new if new > 0 else 0


def calculate_gross_margin(rev, cogs):
    return (rev - cogs) / rev if rev > 0 else 0


def calculate_customer_lifetime(churn_rate):
    return 1 / churn_rate if churn_rate > 0 else 0


def calculate_ltv(arpa, margin, rev_churn):
    return arpa * margin / rev_churn if rev_churn > 0 else 0


def calculate_ltv_cac_ratio(ltv, cac):
    return ltv / cac if cac > 0 else 0


def calculate_cac_payback_period(cac, arpa, margin):
    return cac / (arpa * margin) if arpa * margin > 0 else 0


# --- Modified Main Analysis Function ---
def analyze_csv(file, revenue_multiple=6.0, sde_multiple=4.0, ebitda_multiple=5.5):
    """
    Analyzes the uploaded CSV and returns a text summary, a PDF, and plots.
    """
    if file is None:
        return "Please upload a CSV file.", None, None, None, None, None

    try:
        df = pd.read_csv(file)
        df["Date"] = pd.to_datetime(df["Date"])

        if len(df) < 13:
            return (
                "Insufficient data in CSV. Need at least 13 months for full analysis.",
                None,
                None,
                None,
                None,
                None,
            )

        # --- Generate Visualizations ---
        plot1, plot2, plot3, plot4 = create_visualizations(df)

        # --- Set Analysis Period and Assumptions ---
        last_month = df.iloc[-1]
        last_12_months = df.iloc[-13:-1]
        prior_12_months = df.iloc[:12] if len(df) >= 24 else df.iloc[:-13]

        output = []

        # --- Calculate Annual Metrics ---
        output.append("=" * 50)
        output.append(
            f"ANALYSIS FOR LAST 12 MONTHS ({last_12_months['Date'].min().strftime('%Y-%m')} to {last_12_months['Date'].max().strftime('%Y-%m')})"
        )
        output.append("=" * 50)

        total_revenue_last_12m = last_12_months["Total_Revenue"].sum()
        total_cogs_last_12m = last_12_months["COGS"].sum()
        total_opex_last_12m = last_12_months["OpEx"].sum()
        total_owner_comp_last_12m = last_12_months["Owner_Compensation"].sum()
        total_sm_spend_last_12m = last_12_months["Sales_And_Marketing_Spend"].sum()

        mrr_end_of_year = last_12_months.iloc[-1]["MRR_End"]
        arr_current = calculate_arr(mrr_end_of_year)
        arr_prior = calculate_arr(prior_12_months.iloc[-1]["MRR_End"])
        yoy_growth = calculate_yoy_growth(arr_current, arr_prior)

        output.append(f"Annual Recurring Revenue (ARR): ${arr_current:,.2f}")
        output.append(f"YoY ARR Growth: {yoy_growth:.2%}")

        sde_annual = calculate_sde(
            total_revenue_last_12m,
            total_cogs_last_12m,
            (total_opex_last_12m + total_sm_spend_last_12m),
            total_owner_comp_last_12m,
        )
        ebitda_annual = (
            total_revenue_last_12m
            - total_cogs_last_12m
            - total_opex_last_12m
            - total_sm_spend_last_12m
            - total_owner_comp_last_12m
        )

        output.append(f"Seller's Discretionary Earnings (SDE): ${sde_annual:,.2f}")
        output.append(f"EBITDA: ${ebitda_annual:,.2f}")

        output.append("\n--- Valuations ---")
        output.append(
            f"Revenue-Based Valuation ({revenue_multiple:.1f}x ARR): ${calculate_valuation_revenue(arr_current, revenue_multiple):,.2f}"
        )
        output.append(
            f"SDE-Based Valuation ({sde_multiple:.1f}x SDE): ${calculate_valuation_sde(sde_annual, sde_multiple):,.2f}"
        )
        output.append(
            f"EBITDA-Based Valuation ({ebitda_multiple:.1f}x EBITDA): ${calculate_valuation_ebitda(ebitda_annual, ebitda_multiple):,.2f}"
        )

        ebitda_margin_annual = (
            ebitda_annual / total_revenue_last_12m if total_revenue_last_12m > 0 else 0
        )
        rule_of_40_score = calculate_rule_of_40(
            yoy_growth * 100, ebitda_margin_annual * 100
        )
        output.append("\n--- Health Metrics ---")
        output.append(f"EBITDA Margin: {ebitda_margin_annual:.2%}")
        output.append(
            f"Rule of 40 Score: {rule_of_40_score:.2f} (Target > 40 is healthy)"
        )

        # --- Calculate Monthly Metrics ---
        output.append("\n" + "=" * 50)
        output.append(
            f"ANALYSIS FOR LATEST MONTH ({last_month['Date'].strftime('%Y-%m')})"
        )
        output.append("=" * 50)

        mrr_now = last_month["MRR_End"]
        arpa_monthly = calculate_arpa(mrr_now, last_month["Total_Customers_End"])
        customer_churn_rate_monthly = calculate_customer_churn_rate(
            last_month["Churned_Customers"], last_month["Total_Customers_Start"]
        )
        gross_rev_churn_rate_monthly = calculate_gross_revenue_churn_rate(
            last_month["Churned_Revenue"], last_month["MRR_Start"]
        )
        net_rev_churn_rate_monthly = calculate_net_revenue_churn_rate(
            last_month["Churned_Revenue"],
            last_month["Expansion_Revenue"],
            last_month["MRR_Start"],
        )
        nrr_monthly = calculate_nrr(
            last_month["MRR_Start"],
            last_month["Expansion_Revenue"],
            last_month["Churned_Revenue"],
        )

        output.append("--- Revenue & Churn ---")
        output.append(f"Average Revenue Per Account (ARPA): ${arpa_monthly:,.2f}")
        output.append(f"Customer Churn Rate: {customer_churn_rate_monthly:.2%}")
        output.append(f"Gross Revenue Churn Rate: {gross_rev_churn_rate_monthly:.2%}")
        output.append(f"Net Revenue Churn Rate: {net_rev_churn_rate_monthly:.2%}")
        output.append(f"Net Revenue Retention (NRR): {nrr_monthly:.2%}")

        cac_monthly = calculate_cac(
            last_month["Sales_And_Marketing_Spend"], last_month["New_Customers"]
        )
        gross_margin_monthly = calculate_gross_margin(
            last_month["Total_Revenue"], last_month["COGS"]
        )
        customer_lifetime_months = calculate_customer_lifetime(
            customer_churn_rate_monthly
        )
        ltv = calculate_ltv(
            arpa_monthly, gross_margin_monthly, gross_rev_churn_rate_monthly
        )
        ltv_cac_ratio = calculate_ltv_cac_ratio(ltv, cac_monthly)
        payback_period_months = calculate_cac_payback_period(
            cac_monthly, arpa_monthly, gross_margin_monthly
        )

        output.append("\n--- Unit Economics ---")
        output.append(f"Gross Margin: {gross_margin_monthly:.2%}")
        output.append(f"Customer Acquisition Cost (CAC): ${cac_monthly:,.2f}")
        output.append(f"Customer Lifetime: {customer_lifetime_months:.1f} months")
        output.append(f"Customer Lifetime Value (LTV): ${ltv:,.2f}")
        output.append(f"LTV:CAC Ratio: {ltv_cac_ratio:.2f}:1 (Target > 3:1 is healthy)")
        output.append(
            f"CAC Payback Period: {payback_period_months:.1f} months (Target < 12 is healthy)"
        )

        analysis_text = "\n".join(output)
        pdf_file_path = create_pdf_report(analysis_text)

        return analysis_text, pdf_file_path, plot1, plot2, plot3, plot4

    except Exception as e:
        return f"Error processing file: {str(e)}", None, None, None, None, None


# --- Updated Gradio Interface ---
demo = gr.Interface(
    fn=analyze_csv,
    inputs=[
        gr.File(label="Upload SaaS Metrics CSV File", file_types=[".csv"]),
        gr.Number(label="Revenue Multiple", value=6.0),
        gr.Number(label="SDE Multiple", value=4.0),
        gr.Number(label="EBITDA Multiple", value=5.5),
    ],
    outputs=[
        gr.Textbox(label="Analysis Results", lines=20),
        gr.File(label="Download PDF Report"),
        gr.Plot(label="MRR Trend"),
        gr.Plot(label="Customer Growth Trend"),
        gr.Plot(label="LTV vs. CAC (Last Month)"),
        gr.Plot(label="Net Revenue Retention (NRR) Trend"),
    ],
    title="SaaS Metrics Analyzer with Visualizations",
    description="Upload a CSV file with SaaS metrics data. The app will analyze the last 12 months, the latest month, generate key visualizations, and produce a downloadable PDF report.",
    allow_flagging="never",
    examples=[["demo.csv", 6.0, 4.0, 5.5]],
)

if __name__ == "__main__":
    demo.launch()