import json
import os
import gradio as gr
from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas
from reportlab.lib import colors
from io import BytesIO  # For saving the PDF to memory

PAGE_WIDTH, PAGE_HEIGHT = letter

def load_json_from_file(file):
    # Gradio file input 'file' is a NamedString object
    # Access the file content as bytes via 'file.data'
    file_content = file.data.decode("utf-8")  # Decode file bytes to string
    return json.loads(file_content)  # Parse the string into a Python dictionary

def generate_pdf(data):
    buffer = BytesIO()  # Create an in-memory file-like object to hold the PDF

    c = canvas.Canvas(buffer, pagesize=letter)
    page_created = False

    for ad_size, ad_data in data.items():
        for item in ad_data:
            for line in item.get("text_lines", []):
                page_created = True

                text = line.get("text", "")
                bbox = line.get("bbox", None)

                if not bbox:
                    continue

                x1, y1, x2, y2 = bbox

                pdf_x = x1
                pdf_y = PAGE_HEIGHT - y2

                box_height = y2 - y1
                font_size = max(6, min(18, box_height * 0.8))

                # Debug box
                c.setStrokeColor(colors.lightgrey)
                c.rect(
                    x1,
                    PAGE_HEIGHT - y2,
                    x2 - x1,
                    box_height,
                    fill=0
                )

                if "<b>" in text:
                    c.setFont("Helvetica-Bold", font_size)
                    text = text.replace("<b>", "").replace("</b>", "")
                else:
                    c.setFont("Helvetica", font_size)

                c.setFillColor(colors.black)
                c.drawString(
                    pdf_x,
                    pdf_y + (box_height - font_size),
                    text
                )

        if page_created:
            c.showPage()

    # 🔥 GUARANTEE at least one page
    if not page_created:
        c.setFont("Helvetica", 12)
        c.drawString(50, 750, "No OCR text found")
        c.showPage()

    c.save()

    buffer.seek(0)  # Move cursor back to the beginning of the BytesIO buffer
    return buffer  # Return the in-memory PDF file

# ---------------- GRADIO INTERFACE ----------------

def process_json_and_generate_pdf(json_file):
    # Read the uploaded file content as JSON
    json_data = load_json_from_file(json_file)
    
    # Generate the PDF and return as buffer
    pdf_buffer = generate_pdf(json_data)
    return pdf_buffer  # Return the buffer for downloading

# Create the Gradio interface
iface = gr.Interface(
    fn=process_json_and_generate_pdf,
    inputs=gr.File(label="Upload JSON File"),  # File input for JSON file
    outputs=gr.File(label="Download Generated PDF"),  # Output the generated PDF file
    title="JSON to PDF Generator",
    description="Upload a JSON file to generate a PDF based on the OCR text data."
)

iface.launch()