import csv
from fpdf import FPDF
import tempfile
import os

def _safe_text_for_pdf(s: object) -> str:
    """
    Ensure text passed to FPDF only contains characters encodable in latin-1.
    FPDF (classic) writes using latin-1 encoding by default and will raise
    an error when encountering characters outside that range (e.g. •).
    This helper replaces unsupported characters with a best-effort replacement
    so PDF generation doesn't fail.
    """
    if s is None:
        return ""
    try:
        text = str(s)
    except Exception:
        text = ""
    # encode -> decode using latin-1 with replacement to avoid exceptions
    return text.encode('latin-1', 'replace').decode('latin-1')
def export_evidence_pack_pdf(data, filename=None):
    """
    Export evidence pack as PDF. Data should include clause, summary, checklist, scenario, metadata.
    Returns path to PDF file.
    """
    pdf = FPDF()
    pdf.add_page()
    pdf.set_font("Arial", "B", size=16)
    pdf.cell(200, 10, txt="Evidence Pack", ln=True, align='C')
    pdf.ln(10)
    
    # Clause section
    pdf.set_font("Arial", "B", size=12)
    pdf.cell(0, 8, txt="Clause:", ln=True)
    pdf.set_font("Arial", size=10)
    clause_text = data.get('clause_text', 'No clause information available')
    pdf.multi_cell(0, 6, _safe_text_for_pdf(clause_text))
    pdf.ln(3)
    
    # Summary section  
    pdf.set_font("Arial", "B", size=12)
    pdf.cell(0, 8, txt="Summary:", ln=True)
    pdf.set_font("Arial", size=10)
    summary_text = data.get('summary', 'No summary available')
    pdf.multi_cell(0, 6, _safe_text_for_pdf(summary_text))
    pdf.ln(3)
    
    # Checklist section
    pdf.set_font("Arial", "B", size=12) 
    pdf.cell(0, 8, txt="Checklist:", ln=True)
    pdf.set_font("Arial", size=10)
    checklist = data.get('role_checklist', [])
    if checklist:
        for item in checklist:
            # use a simple hyphen bullet and sanitize text
            pdf.multi_cell(0, 6, _safe_text_for_pdf(f"- {item}"))
    else:
        pdf.multi_cell(0, 6, "No checklist items available")
    pdf.ln(3)
    
    # Source information section
    pdf.set_font("Arial", "B", size=12)
    pdf.cell(0, 8, txt="Source Information:", ln=True) 
    pdf.set_font("Arial", size=10)
    pdf.multi_cell(0, 6, _safe_text_for_pdf(f"Source: {data.get('source_title', 'Not specified')}"))
    pdf.multi_cell(0, 6, _safe_text_for_pdf(f"Clause ID: {data.get('clause_id', 'Not assigned')}"))
    pdf.multi_cell(0, 6, _safe_text_for_pdf(f"Date: {data.get('date', 'Not specified')}"))
    pdf.multi_cell(0, 6, _safe_text_for_pdf(f"URL: {data.get('url', 'Not available')}"))
    
    # User role and context information
    if data.get('user_role'):
        pdf.multi_cell(0, 6, _safe_text_for_pdf(f"User Role: {data.get('user_role', '').title()}"))
    if data.get('language_preference'):
        pdf.multi_cell(0, 6, _safe_text_for_pdf(f"Language: {data.get('language_preference', '').title()}"))
    
    pdf.ln(5)
    scenario = data.get('scenario_analysis',{})
    if scenario:
        pdf.multi_cell(0, 8, _safe_text_for_pdf(f"Scenario Analysis:"))
        pdf.multi_cell(0, 8, _safe_text_for_pdf(f"Yearly Results: {scenario.get('yearly_results','')}"))
        pdf.multi_cell(0, 8, _safe_text_for_pdf(f"Cumulative Base: {scenario.get('cumulative_base','')}"))
        pdf.multi_cell(0, 8, _safe_text_for_pdf(f"Cumulative Scenario: {scenario.get('cumulative_scenario','')}"))
        pdf.multi_cell(0, 8, _safe_text_for_pdf(f"Optimistic: {scenario.get('optimistic','')}"))
        pdf.multi_cell(0, 8, _safe_text_for_pdf(f"Pessimistic: {scenario.get('pessimistic','')}"))
        pdf.multi_cell(0, 8, _safe_text_for_pdf(f"Driver Breakdown: {scenario.get('driver_breakdown','')}"))
    if not filename:
        filename = os.path.join(tempfile.gettempdir(), f"evidence_pack_{os.getpid()}.pdf")
    pdf.output(filename)
    return filename

def export_evidence_pack_csv(data, filename=None):
    """
    Export evidence pack as CSV. Data should include clause, summary, checklist, scenario, metadata.
    Returns path to CSV file.
    """
    if not filename:
        filename = os.path.join(tempfile.gettempdir(), f"evidence_pack_{os.getpid()}.csv")
    with open(filename, 'w', newline='', encoding='utf-8') as csvfile:
        writer = csv.writer(csvfile)
        writer.writerow(["Field", "Value"])
        writer.writerow(["Clause", data.get('clause_text', 'No clause information available')])
        writer.writerow(["Summary", data.get('summary', 'No summary available')])
        
        # Handle checklist properly
        checklist = data.get('role_checklist', [])
        if checklist:
            checklist_text = '; '.join(checklist)
        else:
            checklist_text = "No checklist items available"
        writer.writerow(["Checklist", checklist_text])
        
        writer.writerow(["Source", data.get('source_title', 'Not specified')])
        writer.writerow(["Clause ID", data.get('clause_id', 'Not assigned')])
        writer.writerow(["Date", data.get('date', 'Not specified')])
        writer.writerow(["URL", data.get('url', 'Not available')])
        
        # Add timestamp if available
        if 'timestamp' in data:
            writer.writerow(["Generated At", data.get('timestamp', '')])
            
        # Add original query if available
        if 'original_query' in data:
            writer.writerow(["Original Query", data.get('original_query', '')])
            
        # Add user context information
        if 'user_role' in data:
            writer.writerow(["User Role", data.get('user_role', '').title()])
        if 'language_preference' in data:
            writer.writerow(["Language Preference", data.get('language_preference', '').title()])
        
        scenario = data.get('scenario_analysis', {})
        if scenario:
            writer.writerow(["=== SCENARIO ANALYSIS ===", ""])
            writer.writerow(["Yearly Results", scenario.get('yearly_results', '')])
            writer.writerow(["Cumulative Base", scenario.get('cumulative_base', '')])
            writer.writerow(["Cumulative Scenario", scenario.get('cumulative_scenario', '')])
            writer.writerow(["Optimistic", scenario.get('optimistic', '')])
            writer.writerow(["Pessimistic", scenario.get('pessimistic', '')])
            writer.writerow(["Driver Breakdown", scenario.get('driver_breakdown', '')])
    return filename