from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from sentence_transformers import SentenceTransformer,util
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LogisticRegression
from fastapi.middleware.cors import CORSMiddleware
import uvicorn
import numpy as np
import pandas as pd

app = FastAPI()

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Allow all origins; restrict this in production
    allow_credentials=True,
    allow_methods=["*"],  # Allow all HTTP methods
    allow_headers=["*"],  # Allow all HTTP headers
)


# Initialize the FastAPI app


# Load the pre-trained SentenceTransformer model
model = SentenceTransformer("Alibaba-NLP/gte-base-en-v1.5", trust_remote_code=True)

# Define the request body schema
class TextInput(BaseModel):
    text: str

# Home route
@app.get("/")
async def home():
    return {"message": "welcome to home page"}

# Define the API endpoint for generating embeddings
@app.post("/embed")
async def generate_embedding(text_input: TextInput):
    """
    Generate a 768-dimensional embedding for the input text.
    Returns the embedding in a structured format with rounded values.
    """
    try:
        # Generate the embedding
        embedding = model.encode(text_input.text, convert_to_tensor=True).cpu().numpy()

        # Round embedding values to 2 decimal places
        rounded_embedding = np.round(embedding, 2).tolist()

        # Return structured response
        return {
            "dimensions": len(rounded_embedding),
            "embeddings": [rounded_embedding]
        }

    except Exception as e:
        # Handle any errors
        raise HTTPException(status_code=500, detail=f"An error occurred: {str(e)}")
    


model = SentenceTransformer("Alibaba-NLP/gte-base-en-v1.5", trust_remote_code=True)
df = pd.read_excel("sms_process_data_main.xlsx")

    # Split the data into training and testing sets
X_train, X_test, y_train, y_test = train_test_split(df["MessageText"], df["label"], test_size=0.2, random_state=42)

    # Generate embeddings for the training data
X_train_embeddings = model.encode(X_train.tolist(), show_progress_bar=True)

    # Initialize and train the Logistic Regression model
logreg_model = LogisticRegression(max_iter=100)
logreg_model.fit(X_train_embeddings, y_train)

# Define input schema
class TextInput(BaseModel):
    text: str

@app.post("/prediction")
async def generate_prediction(text_input: TextInput):
    """
    Predict the label for the given text input using the trained model.
    """
    try:
        # Check if input text is provided
        if not text_input.text.strip():
            raise ValueError("Input text cannot be empty.")

        # Generate embedding for the input text
        new_embedding = model.encode([text_input.text])

        # Predict the label using the trained Logistic Regression model
        prediction = logreg_model.predict(new_embedding).tolist()[0]  # Extract single prediction

        # Return structured response
        return {
            "predicted_label": prediction
        }
    except ValueError as ve:
        raise HTTPException(status_code=400, detail=str(ve))
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"An error occurred: {str(e)}")
    
class SentencesInput(BaseModel):
    sentence1: str
    sentence2: str
@app.post("/text_to_tensor")
def text_to_tensor(input: SentencesInput):
    try:
        # Generate embeddings
        embeddings = model.encode([input.sentence1, input.sentence2])

        # Compute cosine similarity
        cosine_similarity = util.cos_sim(embeddings[0], embeddings[1]).item()

        return {"cosine_similarity": round(cosine_similarity, 3)}
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"An error occurred: {str(e)}")


if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=7860)