app.py

# app.py
import streamlit as st
from Bio import pairwise2
from Bio.pairwise2 import format_alignment

# Page Configuration
st.set_page_config(
    page_title="🧬 DNA Sequence Matcher",
    page_icon="🧬",
    layout="centered"
)

# Header
st.markdown(
    "<h1 style='text-align: center; color: #4CAF50;'>🧬 DNA Sequence Matcher</h1>",
    unsafe_allow_html=True
)
st.markdown(
    "<p style='text-align: center; color: #555;'>Align and compare two DNA sequences using Biopython</p>",
    unsafe_allow_html=True
)

# User Input for DNA Sequences
st.subheader("🔬 Input DNA Sequences")
seq1 = st.text_area("Enter DNA Sequence 1:", placeholder="e.g., ATCGTACGTA")
seq2 = st.text_area("Enter DNA Sequence 2:", placeholder="e.g., ATCGTAGCTA")

# Alignment Parameters
st.subheader("⚙️ Alignment Parameters")
match_score = st.slider("Match Score", min_value=1, max_value=5, value=2)
mismatch_penalty = st.slider("Mismatch Penalty", min_value=-5, max_value=0, value=-1)
gap_open_penalty = st.slider("Gap Open Penalty", min_value=-5, max_value=0, value=-2)
gap_extend_penalty = st.slider("Gap Extend Penalty", min_value=-5.0, max_value=0.0, value=-0.5, step=0.1)

# Perform Alignment
if st.button("🧪 Align Sequences"):
    if not seq1 or not seq2:
        st.warning("⚠️ Please enter both DNA sequences.")
    else:
        alignments = pairwise2.align.globalms(
            seq1,
            seq2,
            match_score,
            mismatch_penalty,
            gap_open_penalty,
            gap_extend_penalty
        )

        # Display Results
        st.subheader("🔍 Alignment Results")
        if alignments:
            for alignment in alignments[:1]:  # Show only the top alignment
                st.code(format_alignment(*alignment))
        else:
            st.error("❌ No alignment could be found.")

# Footer
st.markdown(
    "<hr><p style='text-align: center;'>💻 <b>Developed by ChatGPT</b></p>",
    unsafe_allow_html=True
)