from fastapi import FastAPI, UploadFile, File
import pdfplumber
import docx
import io
import re

app = FastAPI()

# 🔥 CONFIGURACIÓN CLAVE
MAX_PAGES = 3
MAX_CHARS = 15000

@app.post("/extract-text/")
async def extract_text(file: UploadFile = File(...)):
    content = await file.read()

    filename = file.filename.lower()

    if filename.endswith(".pdf"):
        text = extract_pdf(content)
    elif filename.endswith(".docx"):
        text = extract_docx(content)
    else:
        return {"error": "Formato no soportado"}

    return {"text": clean_text(text)}


# ✅ PDF (eficiente en memoria)
def extract_pdf(content):
    text = ""

    with pdfplumber.open(io.BytesIO(content)) as pdf:
        pages = min(len(pdf.pages), MAX_PAGES)

        for i in range(pages):
            page = pdf.pages[i]
            extracted = page.extract_text()

            if extracted:
                text += extracted + "\n"

            # 🔥 cortar si ya es muy grande
            if len(text) > MAX_CHARS:
                break

    return text[:MAX_CHARS]


# ✅ DOCX
def extract_docx(content):
    doc = docx.Document(io.BytesIO(content))
    
    text = "\n".join([p.text for p in doc.paragraphs])

    return text[:MAX_CHARS]


# ✅ Limpieza estándar
def clean_text(text):
    text = re.sub(r'\n+', '\n', text)
    text = re.sub(r'\s+', ' ', text)
    return text.strip()