from pptx import Presentation
from docx import Document
import pdfplumber
from reportlab.lib.pagesizes import letter
from pathlib import Path
import re
import pandas as pd
import pdfplumber
from concurrent.futures import ThreadPoolExecutor
from reportlab.platypus import SimpleDocTemplate, Paragraph
from reportlab.lib.styles import getSampleStyleSheet


def extract_text(file_path: Path, file_type: str) -> str:
    text = ""

    if file_type == "txt":
        with open(file_path, "r", encoding="utf-8") as f:
            text = f.read()

    elif file_type == "docx":
        doc = Document(file_path)
        return "\n".join([para.text for para in doc.paragraphs if para.text.strip()])

    elif file_type == "xlsx":
        df = pd.read_excel(file_path, engine="openpyxl")
        return df.to_string(index=False, header=False).strip()

    elif file_type == "pptx":
        prs = Presentation(file_path)
        text_parts = []
        for slide in prs.slides:
            for shape in slide.shapes:
                if shape.has_text_frame:
                    text_parts.append(shape.text_frame.text.strip())
                elif shape.has_table:
                    for row in shape.table.rows:
                        for cell in row.cells:
                            if cell.text.strip():
                                text_parts.append(cell.text.strip())
        
        return "\n".join(text_parts)
        
    elif file_type == "pdf":
        with pdfplumber.open(file_path) as pdf:
            def extract_page(page):
                return page.extract_text_simple() or ""
            with ThreadPoolExecutor() as executor:
                text_parts = list(executor.map(extract_page, pdf.pages))
        return "\n".join(part for part in text_parts if part).strip()

    return text

def save_file(text: str, file_type: str, output_path: Path):
    if file_type == "docx":
        doc = Document()
        doc.add_paragraph(text)
        doc.save(output_path)

    elif file_type == "xlsx":
        df = pd.DataFrame(text.split("\n"), columns=["Content"])
        df.to_excel(output_path, index=False, engine="xlsxwriter")

    elif file_type == "pptx":
        prs = Presentation()
        slide_layout = prs.slide_layouts[1]
        text_lines = text.split('\n')
        chunks = [text_lines[i:i+25] for i in range(0, len(text_lines), 25)]

        for chunk in chunks:
            slide = prs.slides.add_slide(slide_layout)
            content = slide.shapes.placeholders[1]
            text_frame = content.text_frame
            text_frame.clear()
            text_frame.text = "\n".join(chunk)
        
        prs.save(output_path)

    elif file_type == "pdf":
        doc = SimpleDocTemplate(str(output_path), pagesize=letter)
        styles = getSampleStyleSheet()
        flowables = [Paragraph(line, styles["Normal"]) for line in text.split("\n") if line.strip()]
        doc.build(flowables)

    else:
        with open(output_path, "w", encoding="utf-8") as f:
            f.write(text)


def verify_summary(summary: str, original: str) -> str:
    """Simplified verification using word matching"""
    original_lower = original.lower()
    verified = []
    
    for sentence in summary.split('.'):
        sentence = sentence.strip()
        if not sentence:
            continue
            
        # Count matching words (minimum 3 letters)
        matches = 0
        total_words = 0
        for word in sentence.lower().split():
            if len(word) >= 3 and word in original_lower:
                matches += 1
            total_words += 1
        
        # Keep sentence if at least 30% of significant words match
        if total_words > 0 and (matches / total_words) >= 0.3:
            verified.append(sentence)
    
    return '. '.join(verified) if verified else summary[:500]

def ensure_complete_sentences(text: str) -> str:
    if not text or not isinstance(text, str):
        return "" 
    
    try:
        text = ' '.join(text.split())
        sentences = re.split(r'(?<=[.!?])\s+', text)
        valid_sentences = [
            s.strip() for s in sentences 
            if s.strip() and s[-1] in {'.', '!', '?'}
        ]
        
        reconstructed = ' '.join(valid_sentences)
        
        # Final safety check
        if not reconstructed.endswith(('.', '!', '?')):
            last_break = max(
                reconstructed.rfind('.'), 
                reconstructed.rfind('!'), 
                reconstructed.rfind('?')
            )
            if last_break > 0:
                reconstructed = reconstructed[:last_break + 1]
            else:
                reconstructed = reconstructed + '.' if reconstructed else ""
                
        return reconstructed
    
    except Exception:
        return text