import os
import uuid
import io
import shutil
import fitz  # PyMuPDF
import gradio as gr
from pptx import Presentation
from pptx.util import Inches
from docx import Document
from docx.shared import Cm
from PIL import Image

# -------------------------
# Configuration
# -------------------------
UPLOAD_DIR = "uploads"
os.makedirs(UPLOAD_DIR, exist_ok=True)
MAX_FILE_SIZE_MB = 500

# -------------------------
# Core Conversion Logic
# -------------------------
def convert_pdf(file_path, target_format):
    if file_path is None:
        raise gr.Error("Please upload a PDF file.")

    if not file_path.lower().endswith(".pdf"):
        raise gr.Error("Only PDF files are supported.")

    unique_id = str(uuid.uuid4())
    pdf_path = os.path.join(UPLOAD_DIR, f"{unique_id}.pdf")

    # ✅ FIX: copy file instead of file.read()
    shutil.copy(file_path, pdf_path)

    doc = fitz.open(pdf_path)
    if len(doc) == 0:
        doc.close()
        os.remove(pdf_path)
        raise gr.Error("The uploaded PDF is empty.")

    # ---------- PDF → PPT ----------
    if target_format == "PowerPoint (.pptx)":
        output_path = os.path.join(UPLOAD_DIR, f"{unique_id}.pptx")
        prs = Presentation()
        prs.slide_width = Inches(13.333)
        prs.slide_height = Inches(7.5)

        for page in doc:
            pix = page.get_pixmap(matrix=fitz.Matrix(1.5, 1.5), alpha=False)
            img = Image.frombytes("RGB", [pix.width, pix.height], pix.samples)

            img_stream = io.BytesIO()
            img.save(img_stream, format="JPEG", quality=80)
            img_stream.seek(0)

            slide = prs.slides.add_slide(prs.slide_layouts[6])
            slide.shapes.add_picture(
                img_stream, 0, 0,
                width=prs.slide_width,
                height=prs.slide_height
            )
            img_stream.close()

        prs.save(output_path)

    # ---------- PDF → Word ----------
    else:
        output_path = os.path.join(UPLOAD_DIR, f"{unique_id}.docx")
        word_doc = Document()

        for section in word_doc.sections:
            section.top_margin = Cm(0.5)
            section.bottom_margin = Cm(0.5)
            section.left_margin = Cm(0.5)
            section.right_margin = Cm(0.5)

        for i, page in enumerate(doc):
            pix = page.get_pixmap(matrix=fitz.Matrix(1.5, 1.5), alpha=False)
            img = Image.frombytes("RGB", [pix.width, pix.height], pix.samples)

            img_stream = io.BytesIO()
            img.save(img_stream, format="JPEG", quality=80)
            img_stream.seek(0)

            word_doc.add_picture(img_stream, width=Cm(20))
            if i < len(doc) - 1:
                word_doc.add_page_break()
            img_stream.close()

        word_doc.save(output_path)

    doc.close()
    os.remove(pdf_path)
    return output_path

# -------------------------
# Utility: Clear Files
# -------------------------
def clear_files():
    for f in os.listdir(UPLOAD_DIR):
        try:
            os.remove(os.path.join(UPLOAD_DIR, f))
        except:
            pass
    return None

# -------------------------
# Gradio UI
# -------------------------
with gr.Blocks(title="PDF Converter | Developer: Najaf Ali Sharqi") as demo:
    gr.Markdown("""
    # 📄 PDF Conversion Tool
    **Developer:** Najaf Ali Sharqi  

    Convert PDF files generated by NotebookLM into **editable PowerPoint or Word documents**  
    without modifying original content, layout, or images.
    """)

    with gr.Row():
        pdf_input = gr.File(
            label="Upload PDF File",
            file_types=[".pdf"]
        )

        format_choice = gr.Radio(
            choices=["PowerPoint (.pptx)", "Word Document (.docx)"],
            value="PowerPoint (.pptx)",
            label="Select Output Format"
        )

    with gr.Row():
        convert_btn = gr.Button("Convert")
        clear_btn = gr.Button("Clear Uploaded Files")

    output_file = gr.File(label="Download Converted File")

    convert_btn.click(
        fn=convert_pdf,
        inputs=[pdf_input, format_choice],
        outputs=output_file
    )

    clear_btn.click(
        fn=clear_files,
        outputs=output_file
    )

    gr.Markdown("""
    ---
    ⚠️ **Important Notes**
    - UI instructions are provided in English only  
    - The tool does **not** add, remove, or modify content  
    - Output files preserve original visuals exactly  
    - Designed for Hugging Face deployment using Gradio  
    """)

# -------------------------
# Launch (HF Compatible)
# -------------------------
demo.launch(
    server_name="0.0.0.0",
    server_port=7860,
    ssr_mode=False
)