from fpdf import FPDF
import os
from datetime import datetime

REPORT_DIR = os.path.join(os.path.dirname(os.path.dirname(__file__)), "static", "reports")
if not os.path.exists(REPORT_DIR):
    os.makedirs(REPORT_DIR)

class PDFReport(FPDF):
    def __init__(self, title="BMS AI Assistant Report"):
        super().__init__()
        self.report_title = title

    def header(self):
        self.set_font('Arial', 'B', 15)
        self.cell(0, 10, self.report_title, 0, 1, 'C')
        self.ln(10)

    def footer(self):
        self.set_y(-15)
        self.set_font('Arial', 'I', 8)
        self.cell(0, 10, 'Page ' + str(self.page_no()), 0, 0, 'C')

def generate_forecast_pdf(item_code, forecast_data, location=None):
    pdf = PDFReport("Demand Forecasting Report")
    pdf.add_page()
    
    # Title Info
    pdf.set_font('Arial', 'B', 12)
    pdf.cell(0, 10, f'Item: {item_code}', 0, 1)
    pdf.cell(0, 10, f'Location: {location if location else "All Locations"}', 0, 1)
    pdf.cell(0, 10, f'Date Generated: {datetime.now().strftime("%Y-%m-%d %H:%M")}', 0, 1)
    pdf.ln(10)
    
    # Table Header
    pdf.set_font('Arial', 'B', 10)
    pdf.cell(60, 10, 'Date', 1)
    pdf.cell(40, 10, 'Quantity', 1)
    pdf.ln()
    
    # Table Data
    pdf.set_font('Arial', '', 10)
    total_qty = 0
    for row in forecast_data:
        pdf.cell(60, 10, str(row['date']), 1)
        pdf.cell(40, 10, str(row['qty']), 1)
        pdf.ln()
        total_qty += row['qty']
        
    pdf.ln(5)
    pdf.set_font('Arial', 'B', 10)
    pdf.cell(60, 10, 'Total Forecasted Demand:', 0)
    pdf.cell(40, 10, str(total_qty), 0)
    
    filename = f"forecast_{item_code}_{datetime.now().strftime('%Y%m%d%H%M%S')}.pdf"
    filepath = os.path.join(REPORT_DIR, filename)
    pdf.output(filepath)
    
    return filename

def generate_inventory_pdf(item_code, inventory_data, location=None):
    pdf = PDFReport("Inventory Report")
    pdf.add_page()
    
    # Title Info
    pdf.set_font('Arial', 'B', 12)
    pdf.cell(0, 10, f'Item: {item_code}', 0, 1)
    pdf.cell(0, 10, f'Location: {location if location else "All Locations"}', 0, 1)
    pdf.cell(0, 10, f'Date Generated: {datetime.now().strftime("%Y-%m-%d %H:%M")}', 0, 1)
    pdf.ln(10)
    
    # Table Header
    pdf.set_font('Arial', 'B', 10)
    pdf.cell(30, 10, 'Location', 1)
    pdf.cell(20, 10, 'Qty', 1)
    pdf.cell(30, 10, 'Status', 1)
    pdf.cell(30, 10, 'Bin', 1)
    pdf.cell(30, 10, 'Lot', 1)
    pdf.cell(30, 10, 'Expiry', 1)
    pdf.ln()
    
    # Table Data
    pdf.set_font('Arial', '', 10)
    total_on_hand = 0
    for row in inventory_data:
        loc = row.get('region', 'Unknown')
        qty = row.get('qty_on_hand', 0)
        status = row.get('status', 'Unknown')
        
        bin_loc = row.get('bin_location', '-') or '-'
        lot = row.get('lot_number', '-') or '-'
        expiry = row.get('expiry_date', '-') or '-'
        
        pdf.cell(30, 10, str(loc)[:15], 1)
        pdf.cell(20, 10, str(qty), 1)
        pdf.cell(30, 10, str(status), 1)
        pdf.cell(30, 10, str(bin_loc), 1)
        pdf.cell(30, 10, str(lot), 1)
        pdf.cell(30, 10, str(expiry), 1)
        pdf.ln()
        try:
            total_on_hand += int(qty)
        except:
            pass
        
    pdf.ln(5)
    pdf.set_font('Arial', 'B', 10)
    pdf.cell(60, 10, 'Total On Hand:', 0)
    pdf.cell(40, 10, str(total_on_hand), 0)
    
    filename = f"inventory_{item_code}_{datetime.now().strftime('%Y%m%d%H%M%S')}.pdf"
    filepath = os.path.join(REPORT_DIR, filename)
    pdf.output(filepath)
    
    return filename

def generate_general_pdf(title, content):
    pdf = PDFReport(title)
    pdf.add_page()
    
    pdf.set_font('Arial', 'B', 12)
    pdf.cell(0, 10, title, 0, 1)
    pdf.ln(5)
    
    pdf.set_font('Arial', '', 10)
    pdf.multi_cell(0, 10, content)
    
    filename = f"report_{datetime.now().strftime('%Y%m%d%H%M%S')}.pdf"
    filepath = os.path.join(REPORT_DIR, filename)
    pdf.output(filepath)
    
    return filename

def generate_competitor_pdf(item_code, analysis_data, insights):
    pdf = PDFReport("Competitor Analysis Report")
    pdf.add_page()
    
    # Title Info
    pdf.set_font('Arial', 'B', 12)
    pdf.cell(0, 10, f'Item: {item_code}', 0, 1)
    pdf.cell(0, 10, f'Date Generated: {datetime.now().strftime("%Y-%m-%d %H:%M")}', 0, 1)
    pdf.ln(5)
    
    # Insights Section
    pdf.set_fill_color(230, 255, 250) # Light teal background
    pdf.set_font('Arial', 'B', 11)
    pdf.cell(0, 10, "Expert Market Insights:", 0, 1)
    pdf.set_font('Arial', 'I', 10)
    # Clean up markdown bolding for PDF
    clean_insights = insights.replace("**", "").replace("<br>", "\n")
    pdf.multi_cell(0, 8, clean_insights, 0, 'L', True)
    pdf.ln(10)

    # Table Header
    pdf.set_font('Arial', 'B', 10)
    pdf.cell(20, 10, 'Year', 1)
    pdf.cell(30, 10, 'Comp Price', 1)
    pdf.cell(30, 10, 'Our Price', 1)
    pdf.cell(30, 10, 'Sales Qty', 1)
    pdf.cell(25, 10, 'Share %', 1)
    pdf.cell(25, 10, 'Rating', 1)
    pdf.ln()
    
    # Table Data
    pdf.set_font('Arial', '', 10)
    for row in analysis_data:
        share = row.get('market_share_percentage', 'N/A') or 'N/A'
        rating = row.get('customer_rating', 'N/A') or 'N/A'
        
        try:
            share_val = float(share)
            share_str = f"{share_val:.2f}%"
        except:
            share_str = f"{share}%"
            
        try:
            rating_val = float(rating)
            rating_str = f"{rating_val:.2f}"
        except:
            rating_str = str(rating)
            
        pdf.cell(20, 10, str(row['year']), 1)
        pdf.cell(30, 10, f"${row['competitor_price']:.2f}", 1)
        pdf.cell(30, 10, f"${row['our_price']:.2f}", 1)
        pdf.cell(30, 10, str(row['sales_qty']), 1)
        pdf.cell(25, 10, share_str, 1)
        pdf.cell(25, 10, rating_str, 1)
        pdf.ln()
        
    filename = f"competitor_{item_code}_{datetime.now().strftime('%Y%m%d%H%M%S')}.pdf"
    filepath = os.path.join(REPORT_DIR, filename)
    pdf.output(filepath)
    
    return filename

def generate_lost_sales_pdf(item_code, loss_data, location=None):
    pdf = PDFReport("Lost Sales Analysis Report")
    pdf.add_page()
    
    # Title Info
    pdf.set_font('Arial', 'B', 12)
    pdf.cell(0, 10, f'Item: {item_code if item_code else "All Items"}', 0, 1)
    if location:
        pdf.cell(0, 10, f'Location: {location}', 0, 1)
    pdf.cell(0, 10, f'Date Generated: {datetime.now().strftime("%Y-%m-%d %H:%M")}', 0, 1)
    pdf.ln(10)
    
    # Table Header
    pdf.set_font('Arial', 'B', 10)
    pdf.cell(60, 10, 'Primary Reason', 1)
    pdf.cell(40, 10, 'Lost Qty', 1)
    pdf.cell(50, 10, 'Est. Revenue Lost', 1)
    pdf.ln()
    
    # Table Data
    pdf.set_font('Arial', '', 10)
    total_rev = 0
    
    # Sort by lost qty desc
    sorted_data = sorted(loss_data, key=lambda x: x['lost_qty'], reverse=True)
    
    for row in sorted_data:
        pdf.cell(60, 10, str(row['reason']), 1)
        pdf.cell(40, 10, str(row['lost_qty']), 1)
        pdf.cell(50, 10, f"${row['estimated_revenue_lost']:,.2f}", 1)
        pdf.ln()
        total_rev += row['estimated_revenue_lost']
        
    pdf.ln(5)
    pdf.set_font('Arial', 'B', 10)
    pdf.cell(100, 10, 'Total Estimated Loss:', 0)
    pdf.cell(50, 10, f"${total_rev:,.2f}", 0)
    
    filename = f"lost_sales_{item_code if item_code else 'summary'}_{datetime.now().strftime('%Y%m%d%H%M%S')}.pdf"
    filepath = os.path.join(REPORT_DIR, filename)
    pdf.output(filepath)
    
    return filename