import streamlit as st
from langchain.text_splitter import RecursiveCharacterTextSplitter, CharacterTextSplitter, Language
import tiktoken


CHARACTER_LENGTH = "length_function=lambda x: len(x)"
TOKEN_LENGTH = """enc = tiktoken.get_encoding("cl100k_base")
length_function = lambda text: len(enc.encode(text))
"""
CHARACTER = """CharacterTextSplitter(
    separator="\\n\\n",
    chunk_size={chunk_size},
    chunk_overlap={chunk_overlap},
    length_function={length_function}
)
"""
RECURSIVE_CHARACTER = """RecursiveCharacterTextSplitter(
    chunk_size={chunk_size},
    chunk_overlap={chunk_overlap},
    length_function={length_function}
)
"""
LANGUAGE = """RecursiveCharacterTextSplitter.from_language(
    language="{language}",
    chunk_size={chunk_size},
    chunk_overlap={chunk_overlap},
    length_function={length_function}
)
"""

# Streamlit UI
st.title("Understand Chunk and Token")


col1, col2, col3, col4 = st.columns([1, 1, 1, 2])

with col1:
    chunk_size = st.number_input(
        min_value=1,
        label="Chunk Size",
        value=1000
    )

with col2:
    chunk_overlap = st.number_input(
        min_value=1,
        max_value=chunk_size - 1,
        label="Chunk Overlap",
        value=int(chunk_size * 0.2)
    )

    if chunk_overlap >= chunk_size:
        st.warning("Achtung: Chunk Overlap sollte kleiner als die Chunk Size sein!")

with col3:
    length_function_option = st.selectbox(
        "Length Function",
        ["Characters", "Tokens"]
    )

splitter_choices = ["RecursiveCharacter", "Character"] + [f"Language.{v.name}" for v in Language]

with col4:
    splitter_choice = st.selectbox(
        "Select a Text Splitter",
        splitter_choices
    )

# Auswählen der passenden length_function
if length_function_option == "Characters":
    # Messen in Zeichen
    length_function = len
    length_function_str = CHARACTER_LENGTH
elif length_function_option == "Tokens":
    # Messen in Tokens mithilfe tiktoken
    enc = tiktoken.get_encoding("cl100k_base")
    def length_function(text: str) -> int:
        return len(enc.encode(text))
    length_function_str = TOKEN_LENGTH
else:
    raise ValueError("Ungültige Option für length_function.")


# Text-Eingabe
doc = st.text_area("Füge hier deinen Text ein:")

# Button zum Splitten des Textes
if st.button("Split Text"):
    # Erzeugen des Splitter-Objekts basierend auf der Auswahl
    if splitter_choice == "Character":
        splitter = CharacterTextSplitter(
            separator="\n\n",
            chunk_size=chunk_size,
            chunk_overlap=chunk_overlap,
            length_function=length_function
        )
    elif splitter_choice == "RecursiveCharacter":
        splitter = RecursiveCharacterTextSplitter(
            chunk_size=chunk_size,
            chunk_overlap=chunk_overlap,
            length_function=length_function
        )
    elif "Language." in splitter_choice:
        lang = splitter_choice.split(".")[1].lower()
        splitter = RecursiveCharacterTextSplitter.from_language(
            language=lang,
            chunk_size=chunk_size,
            chunk_overlap=chunk_overlap,
            length_function=length_function
        )
    else:
        raise ValueError("Ungültige Wahl beim Text Splitter.")
    
    # Aufteilen des Textes
    splits = splitter.split_text(doc)

    # Ausgabe der erstellten Textsplitter
    for idx, split in enumerate(splits, start=1):
        st.text_area(f"Teilstück {idx}", split, height=150)