import os
import gradio as gr
from openai import OpenAI
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.pagesizes import letter
from reportlab.lib import colors

# Load OpenAI key from Hugging Face Secrets
api_key = os.environ.get("OPENAI_API_KEY")
if not api_key:
    raise ValueError("Please add OPENAI_API_KEY in your Space settings.")

client = OpenAI(api_key=api_key)

# ---------- PDF CREATION ----------
def create_pdf(text, filename="SmartTravelAI_Itinerary.pdf"):
    styles = getSampleStyleSheet()
    
    heading_style = ParagraphStyle(
        'HeadingStyle',
        parent=styles['Heading2'],
        fontSize=16,
        textColor=colors.HexColor("#003366"),
        leading=18,
        spaceBefore=10,
        spaceAfter=6
    )
    
    normal_style = styles['BodyText']

    doc = SimpleDocTemplate(filename, pagesize=letter)
    story = []

    for line in text.split("\n"):
        line = line.strip()

        if not line:
            story.append(Spacer(1, 8))
            continue
        
        # Detect headings like **Overview**
        if line.startswith("**") and line.endswith("**") and len(line) > 4:
            heading = line.replace("**", "")
            story.append(Paragraph(f"<b>{heading}</b>", heading_style))
        else:
            cleaned = line.replace("**", "")
            story.append(Paragraph(cleaned, normal_style))

    doc.build(story)
    return filename


# ---------- AI ITINERARY GENERATION ----------
def generate_itinerary(destination, days, budget):
    system_msg = (
        "You are SmartTravelAI, a professional travel planner. "
        "Return formatted text with bold headings and bullet points."
    )

    user_msg = f"""
    Create a formatted travel itinerary.

    Destination: {destination}
    Days: {days}
    Budget: ${budget} USD

    Requirements:
    - Start with a bold trip title
    - Use headings: **Overview**, **Suggested Cities**, **Daily Plan**, **Budget Tips**
    - Use bullet points
    - Practical, fun, and concise
    """

    response = client.chat.completions.create(
        model="gpt-4o-mini",
        messages=[
            {"role": "system", "content": system_msg},
            {"role": "user", "content": user_msg}
        ]
    )

    itinerary_text = response.choices[0].message.content
    itinerary_text += "\n\n🔗 **Interactive App:** https://huggingface.co/spaces/naaijaz/SmartTravelAI"

    # Create PDF file
    pdf_path = create_pdf(itinerary_text)

    return itinerary_text, pdf_path


# ---------- GRADIO INTERFACE ----------
demo = gr.Interface(
    fn=generate_itinerary,
    inputs=[
        gr.Textbox(label="Destination Country / Region", placeholder="Italy, Japan, Jamaica…"),
        gr.Number(label="Number of Days", value=5),
        gr.Number(label="Budget (USD)", value=2000),
    ],
    outputs=[
        gr.Markdown(label="Itinerary Preview"),
        gr.File(label="Download PDF")
    ],
    title="SmartTravelAI — AI Travel Planner (PDF Enabled)",
    description="Enter details to generate a custom itinerary and download it as a PDF.",
)

demo.launch()