import os
import streamlit as st
import tempfile
import pandas as pd
import json
import xml.etree.ElementTree as ET
import yaml
from dotenv import load_dotenv
from bs4 import BeautifulSoup
from pptx import Presentation
from docx import Document

from langchain.document_loaders import PyPDFLoader, TextLoader
from langchain.indexes import VectorstoreIndexCreator
from langchain.chains import RetrievalQA
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.embeddings import HuggingFaceEmbeddings
from langchain.chains import LLMChain
from langchain.prompts import PromptTemplate

from ibm_watson_machine_learning.foundation_models import Model
from ibm_watson_machine_learning.foundation_models.extensions.langchain import WatsonxLLM
from ibm_watson_machine_learning.metanames import GenTextParamsMetaNames as GenParams
from ibm_watson_machine_learning.foundation_models.utils.enums import DecodingMethods

# Initialize index and chain to None1
index = None
rag_chain = None

# Custom loader for DOCX files
class DocxLoader:
    def __init__(self, file_path):
        self.file_path = file_path

    def load(self):
        document = Document(self.file_path)
        text_content = [para.text for para in document.paragraphs]
        return " ".join(text_content)

# Custom loader for PPTX files
class PptxLoader:
    def __init__(self, file_path):
        self.file_path = file_path

    def load(self):
        presentation = Presentation(self.file_path)
        text_content = [shape.text for slide in presentation.slides for shape in slide.shapes if hasattr(shape, "text")]
        return " ".join(text_content)

# Custom loader for additional file types
def load_csv(file_path):
    df = pd.read_csv(file_path)
    page_size = 100
    page_number = st.number_input("Page number", min_value=1, max_value=(len(df) // page_size) + 1, step=1, value=1)
    start_index = (page_number - 1) * page_size
    end_index = start_index + page_size
    st.dataframe(df.iloc[start_index:end_index])
    return df.to_string(index=False)

def load_json(file_path):
    with open(file_path, 'r') as file:
        data = json.load(file)
    return json.dumps(data, indent=2)

def load_xml(file_path):
    tree = ET.parse(file_path)
    root = tree.getroot()
    return ET.tostring(root, encoding="unicode")

def load_yaml(file_path):
    with open(file_path, 'r') as file:
        data = yaml.safe_load(file)
    return yaml.dump(data)

def load_html(file_path):
    with open(file_path, 'r', encoding='utf-8') as file:
        soup = BeautifulSoup(file, 'html.parser')
    return soup.get_text()

# Caching function to load various file types
@st.cache_resource
def load_file(file_name, file_type):
    loaders = []
    text = None

    if file_type == "pdf":
        loaders = [PyPDFLoader(file_name)]
    elif file_type == "docx":
        loader = DocxLoader(file_name)
        text = loader.load()
    elif file_type == "pptx":
        loader = PptxLoader(file_name)
        text = loader.load()
    elif file_type == "txt":
        loaders = [TextLoader(file_name)]
    elif file_type == "csv":
        text = load_csv(file_name)
    elif file_type == "json":
        text = load_json(file_name)
    elif file_type == "xml":
        text = load_xml(file_name)
    elif file_type == "yaml":
        text = load_yaml(file_name)
    elif file_type == "html":
        text = load_html(file_name)
    elif file_type == "htm":
        text = load_html(file_name)    
    else:
        st.error("Unsupported file type.")
        return None

    if text:
        with tempfile.NamedTemporaryFile(delete=False, suffix=".txt") as temp_file:
            temp_file.write(text.encode("utf-8"))
            temp_file_path = temp_file.name
        loaders = [TextLoader(temp_file_path)]

    if loaders:
        index = VectorstoreIndexCreator(
            embedding=HuggingFaceEmbeddings(model_name="all-MiniLM-L12-v2"),
            text_splitter=RecursiveCharacterTextSplitter(chunk_size=450, chunk_overlap=50)
        ).from_loaders(loaders)
        st.success("Index created successfully!")
        return index
    return None

# Watsonx API setup
load_dotenv()

watsonx_api_key =  os.getenv("WATSONX_API_KEY")
watsonx_project_id = os.getenv("WATSONX_PROJECT_ID")

if not watsonx_api_key or not watsonx_project_id:
    st.error("API Key or Project ID is not set. Please set them as environment variables.")

prompt_template_br = PromptTemplate(
    input_variables=["context", "question"],
    template="""<|begin_of_text|><|start_header_id|>system<|end_header_id|>
I am a helpful assistant.
<|eot_id|>
{context}
<|start_header_id|>user<|end_header_id|>
{question}<|eot_id|>
"""
)

with st.sidebar:
    st.title("Multi-Document Retrieval with Watsonx")
    st.sidebar.write("") 
    st.sidebar.markdown("Developed by **Abdul Rahman H**")
    watsonx_model = st.selectbox("Model", ["meta-llama/llama-3-405b-instruct", "codellama/codellama-34b-instruct-hf", "ibm/granite-20b-multilingual"])
    max_new_tokens = st.slider("Max output tokens", min_value=100, max_value=4000, value=600, step=100)
    decoding_method = st.radio("Decoding", (DecodingMethods.GREEDY.value, DecodingMethods.SAMPLE.value))
    parameters = {
        GenParams.DECODING_METHOD: decoding_method,
        GenParams.MAX_NEW_TOKENS: max_new_tokens,
        GenParams.MIN_NEW_TOKENS: 1,
        GenParams.TEMPERATURE: 0,
        GenParams.TOP_K: 50,
        GenParams.TOP_P: 1,
        GenParams.STOP_SEQUENCES: [],
        GenParams.REPETITION_PENALTY: 1
    }
    st.info("Upload a file to use RAG")
    uploaded_file = st.file_uploader("Upload file", accept_multiple_files=False, type=["pdf", "docx", "txt", "pptx", "csv", "json", "xml", "yaml", "html"])

    if uploaded_file is not None:
        bytes_data = uploaded_file.read()
        st.write("Filename:", uploaded_file.name)
        with open(uploaded_file.name, 'wb') as f:
            f.write(bytes_data)
        file_type = uploaded_file.name.split('.')[-1].lower()
        index = load_file(uploaded_file.name, file_type)

    model_name = watsonx_model

st.info("Setting up Watsonx...")
my_credentials = {
    "url": "https://us-south.ml.cloud.ibm.com",
    "apikey": watsonx_api_key
}
params = parameters
project_id = watsonx_project_id
space_id = None
verify = False
model = WatsonxLLM(model=Model(model_name, my_credentials, params, project_id, space_id, verify))

if model:
    st.info(f"Model {model_name} ready.")
    chain = LLMChain(llm=model, prompt=prompt_template_br, verbose=True)

if chain and index is not None:
    rag_chain = RetrievalQA.from_chain_type(
        llm=model,
        chain_type="stuff",
        retriever=index.vectorstore.as_retriever(),
        chain_type_kwargs={"prompt": prompt_template_br},
        return_source_documents=False,
        verbose=True
    )
    st.info("Document-based retrieval is ready.")
else:
    st.warning("No document uploaded or chain setup issue.")

# Chat loop
if "messages" not in st.session_state:
    st.session_state.messages = []

for message in st.session_state.messages:
    st.chat_message(message["role"]).markdown(message["content"])

prompt = st.chat_input("Ask your question here", disabled=False if chain else True)

if prompt:
    st.chat_message("user").markdown(prompt)
    if rag_chain:
        response_text = rag_chain.run(prompt).strip()
    else:
        response_text = chain.run(question=prompt, context="").strip()
        
    st.session_state.messages.append({'role': 'User', 'content': prompt})
    st.chat_message("assistant").markdown(response_text)
    st.session_state.messages.append({'role': 'Assistant', 'content': response_text})