Create app.py

app.py

@@ -0,0 +1,272 @@
+import streamlit as st
+import torch
+from transformers import MarianMTModel, MarianTokenizer
+
+st.set_page_config(
+    page_title="Language Translation App",
+    page_icon="🌍",
+    layout="wide"
+)
+
+# -----------------------------
+# Custom CSS
+# -----------------------------
+st.markdown("""
+    <style>
+        .block-container {
+            padding-top: 1.5rem;
+            padding-bottom: 2rem;
+            max-width: 1100px;
+        }
+
+        .app-title {
+            font-size: 3.2rem;
+            font-weight: 800;
+            color: #2d2d3a;
+            margin-bottom: 0.25rem;
+        }
+
+        .app-subtitle {
+            font-size: 1.2rem;
+            color: #555;
+            margin-bottom: 1.8rem;
+        }
+
+        .stSelectbox label, .stTextArea label {
+            font-size: 1.05rem !important;
+            font-weight: 600 !important;
+        }
+
+        .stTextArea textarea {
+            font-size: 1.15rem !important;
+            border-radius: 12px !important;
+        }
+
+        .stButton > button {
+            min-width: 140px;
+            height: 48px;
+            font-size: 1rem;
+            font-weight: 600;
+            border-radius: 10px;
+        }
+
+        .result-label {
+            font-size: 1.05rem;
+            font-weight: 600;
+            margin-top: 1rem;
+            margin-bottom: 0.5rem;
+        }
+    </style>
+""", unsafe_allow_html=True)
+
+# -----------------------------
+# Supported languages
+# -----------------------------
+LANGUAGES = {
+    "English": "en",
+    "French": "fr",
+    "German": "de",
+    "Spanish": "es",
+    "Italian": "it",
+    "Portuguese": "pt",
+    "Dutch": "nl",
+    "Romanian": "ro",
+    "Arabic": "ar",
+    "Hindi": "hi",
+}
+
+# -----------------------------
+# Helsinki-NLP OPUS-MT models
+# -----------------------------
+MODEL_MAP = {
+    ("en", "fr"): "Helsinki-NLP/opus-mt-en-fr",
+    ("fr", "en"): "Helsinki-NLP/opus-mt-fr-en",
+
+    ("en", "de"): "Helsinki-NLP/opus-mt-en-de",
+    ("de", "en"): "Helsinki-NLP/opus-mt-de-en",
+
+    ("en", "es"): "Helsinki-NLP/opus-mt-en-es",
+    ("es", "en"): "Helsinki-NLP/opus-mt-es-en",
+
+    ("en", "it"): "Helsinki-NLP/opus-mt-en-it",
+    ("it", "en"): "Helsinki-NLP/opus-mt-it-en",
+
+    ("en", "pt"): "Helsinki-NLP/opus-mt-en-pt",
+    ("pt", "en"): "Helsinki-NLP/opus-mt-pt-en",
+
+    ("en", "nl"): "Helsinki-NLP/opus-mt-en-nl",
+    ("nl", "en"): "Helsinki-NLP/opus-mt-nl-en",
+
+    ("en", "ro"): "Helsinki-NLP/opus-mt-en-ro",
+    ("ro", "en"): "Helsinki-NLP/opus-mt-ro-en",
+
+    ("en", "ar"): "Helsinki-NLP/opus-mt-en-ar",
+    ("ar", "en"): "Helsinki-NLP/opus-mt-ar-en",
+
+    ("en", "hi"): "Helsinki-NLP/opus-mt-en-hi",
+    ("hi", "en"): "Helsinki-NLP/opus-mt-hi-en",
+}
+
+# -----------------------------
+# Session state
+# -----------------------------
+if "input_text" not in st.session_state:
+    st.session_state.input_text = ""
+
+if "translated_text" not in st.session_state:
+    st.session_state.translated_text = ""
+
+if "model_info" not in st.session_state:
+    st.session_state.model_info = ""
+
+# -----------------------------
+# Device
+# -----------------------------
+DEVICE = "cuda" if torch.cuda.is_available() else "cpu"
+
+# -----------------------------
+# Load model + tokenizer
+# -----------------------------
+@st.cache_resource
+def load_model(model_name: str):
+    tokenizer = MarianTokenizer.from_pretrained(model_name)
+    model = MarianMTModel.from_pretrained(model_name)
+    model.to(DEVICE)
+    return tokenizer, model
+
+# -----------------------------
+# Translation function
+# -----------------------------
+def translate_text(text: str, src_lang: str, tgt_lang: str):
+    if src_lang == tgt_lang:
+        return text, "Same language selected"
+
+    pair = (src_lang, tgt_lang)
+
+    if pair not in MODEL_MAP:
+        return None, f"No open-source model available for {src_lang} → {tgt_lang}"
+
+    model_name = MODEL_MAP[pair]
+
+    try:
+        tokenizer, model = load_model(model_name)
+
+        inputs = tokenizer(
+            [text],
+            return_tensors="pt",
+            padding=True,
+            truncation=True,
+            max_length=512
+        )
+
+        inputs = {key: value.to(DEVICE) for key, value in inputs.items()}
+
+        translated_tokens = model.generate(
+            **inputs,
+            max_length=512,
+            num_beams=4,
+            early_stopping=True
+        )
+
+        translated_text = tokenizer.decode(
+            translated_tokens[0],
+            skip_special_tokens=True
+        )
+
+        return translated_text, model_name
+
+    except Exception as e:
+        return None, f"Translation failed: {str(e)}"
+
+# -----------------------------
+# Header
+# -----------------------------
+st.markdown('<div class="app-title">Language Translation App 🌍</div>', unsafe_allow_html=True)
+st.markdown(
+    '<div class="app-subtitle">Translate text between multiple languages using open-source models.</div>',
+    unsafe_allow_html=True
+)
+
+# -----------------------------
+# Language selection
+# -----------------------------
+col1, col2 = st.columns(2)
+
+with col1:
+    source_language_name = st.selectbox(
+        "Select Source Language",
+        list(LANGUAGES.keys()),
+        index=0
+    )
+
+with col2:
+    target_language_name = st.selectbox(
+        "Select Target Language",
+        list(LANGUAGES.keys()),
+        index=2
+    )
+
+source_language = LANGUAGES[source_language_name]
+target_language = LANGUAGES[target_language_name]
+
+# -----------------------------
+# Input area
+# -----------------------------
+input_text = st.text_area(
+    "Enter Text to Translate",
+    value=st.session_state.input_text,
+    height=220,
+    placeholder="Type or paste your text here..."
+)
+
+st.session_state.input_text = input_text
+
+# -----------------------------
+# Buttons
+# -----------------------------
+b1, b2 = st.columns([1, 1])
+
+with b1:
+    translate_button = st.button("Translate")
+
+with b2:
+    clear_button = st.button("Clear")
+
+if clear_button:
+    st.session_state.input_text = ""
+    st.session_state.translated_text = ""
+    st.session_state.model_info = ""
+    st.rerun()
+
+# -----------------------------
+# Translate action
+# -----------------------------
+if translate_button:
+    if not input_text.strip():
+        st.warning("Please enter some text to translate.")
+    else:
+        with st.spinner("Translating..."):
+            translated_text, info = translate_text(
+                input_text.strip(),
+                source_language,
+                target_language
+            )
+
+        if translated_text is None:
+            st.error(info)
+        else:
+            st.session_state.translated_text = translated_text
+            st.session_state.model_info = info
+            st.success("Translation completed successfully.")
+
+# -----------------------------
+# Output area
+# -----------------------------
+if st.session_state.translated_text:
+    st.markdown('<div class="result-label">Translated Text</div>', unsafe_allow_html=True)
+    st.text_area(
+        "",
+        value=st.session_state.translated_text,
+        height=220
+    )
+    st.caption(f"Model used: {st.session_state.model_info}")