app.py

#!/usr/bin/env python3
"""
Sidewalk FM — Small Trader Ledger & Advisor
HuggingFace Build Small Hackathon 2026 — Backyard AI track

Architecture:
  1. Extraction: regex/rules first → NVIDIA NIM backup (nemotron-mini-4b-instruct)
  2. Math: pure Python — never the LLM (deterministic)
  3. Advisory: Modal vLLM (nemotron-mini-4b-instruct) → deterministic fallback

Fully NVIDIA stack. All models ≤4B → Tiny Titan eligible.
Advisory served on Modal for runtime integration → Modal prize eligible.

Models:
  - Extraction backup: nvidia/nemotron-mini-4b-instruct (4B, NIM)
  - Advisory: nvidia/nemotron-mini-4b-instruct (4B, Modal vLLM)
"""

import os
import re
import json
import math
import logging
import base64
from datetime import datetime
from typing import Dict, List, Optional

# --- Config ---------------------------------------------------------------
NIM_API_KEY = os.environ.get("NVIDIA_NIM_API_KEY", "")
NIM_BASE = "https://integrate.api.nvidia.com/v1"

# Modal advisory endpoint (rebuild per P1)
MODAL_BASE = os.environ.get("MODAL_BASE", "")
# e.g. https://joshua-abok--sidewalk-fm-advisor-serve.modal.run/v1

EXTRACTION_MODEL = "nvidia/nemotron-mini-4b-instruct"
ADVISORY_MODEL = "nvidia/nemotron-mini-4b-instruct"

# Ledger state
ledger: List[Dict] = []

# Structured agent traces (📡 badge)
agent_traces: List[Dict] = []

def add_trace(step: str, **kwargs):
    """Log a structured agent trace."""
    trace = {"step": step, "ts": datetime.now().isoformat(), **kwargs}
    agent_traces.append(trace)


# --- Extraction: Deterministic First, LLM Backup --------------------------

TRANSACTION_PATTERNS = [
    re.compile(r'(?i)(?:bought|purchased|got)\s+(\d+(?:\.\d+)?)\s+(\w[\w\s]*?)\s+(?:at|for)\s+(\d+(?:\.\d+)?)\s*(\w*)?'),
    re.compile(r'(?i)(?:sold|gave|exchanged)\s+(\d+(?:\.\d+)?)\s+(\w[\w\s]*?)\s+(?:at|for)\s+(\d+(?:\.\d+)?)\s*(\w*)?'),
    re.compile(r'(?i)(?:return|returned|brought back)\s+(\d+(?:\.\d+)?)\s+(\w[\w\s]*?)'),
    re.compile(r'(?i)(?:bought|purchased)\s+(\d+(?:\.\d+)?)\s+(\w[\w\s]*?)\s+(?:at|for)\s+(\d+(?:\.\d+)?)'),
    re.compile(r'(\d+(?:\.\d+)?)\s+(\w[\w\s]*?)\s+at\s+(\d+(?:\.\d+)?)'),
]

BUY_PATTERN = re.compile(r'(?i)(?:bought|purchased|got|purchase|buy)\b')
SELL_PATTERN = re.compile(r'(?i)(?:sold|gave|exchanged|sell)\b')
RETURN_PATTERN = re.compile(r'(?i)(?:return|returned|brought back)\b')
REFUND_PATTERN = re.compile(r'(?i)(?:refund|got money back)\b')


def extract_deterministic(text: str) -> Optional[Dict]:
    """Extract structured transaction using regex only."""
    text_stripped = text.strip()
    if RETURN_PATTERN.search(text_stripped) or REFUND_PATTERN.search(text_stripped):
        action = "return"
    elif BUY_PATTERN.search(text_stripped):
        action = "buy"
    elif SELL_PATTERN.search(text_stripped):
        action = "sell"
    else:
        action = "buy"
    
    for pattern in TRANSACTION_PATTERNS:
        m = pattern.search(text_stripped)
        if m:
            groups = m.groups()
            if len(groups) >= 3:
                try:
                    qty = float(groups[0])
                except (ValueError, IndexError):
                    continue
                item = groups[1].strip()
                item = re.sub(r'\s+(and|or|but|for|with|from)\s*$', '', item, flags=re.I).strip()
                try:
                    price = float(groups[2])
                except (ValueError, IndexError):
                    continue
                currency = ""
                vendor = ""
                if len(groups) > 3 and groups[3]:
                    cc = groups[3].strip()
                    currency_map = {
                        "shilling": "KES", "shillings": "KES", "sh": "KES", "kes": "KES", "kenya": "KES",
                        "dollar": "USD", "dollars": "USD", "$": "USD", "usd": "USD", "us dollars": "USD",
                        "naira": "NGN", "ngn": "NGN", "nigerian": "NGN",
                        "peso": "MXN", "pesos": "MXN", "mxn": "MXN",
                        "rupee": "INR", "rupees": "INR", "inr": "INR",
                        "euro": "EUR", "eur": "EUR",
                        "pound": "GBP", "gbp": "GBP", "sterling": "GBP",
                        "cfa": "XOF", "yen": "JPY", "jpy": "JPY",
                        "rand": "ZAR", "zar": "ZAR",
                    }
                    currency = currency_map.get(cc.lower(), cc.upper()) if cc.lower() in currency_map else ("KES" if cc.lower() in currency_map else "")
                from_match = re.search(r'from\s+(\w[\w\s]{0,30}?)(?:\s+(?:at|for|and|but|with|$))', text_stripped)
                if from_match:
                    vendor = from_match.group(1).strip()
                return {
                    "action": action, "item": item,
                    "quantity": round(qty, 2), "unit_price": round(price, 2),
                    "currency": currency if currency else "KES",
                    "vendor": vendor if vendor else None,
                }
    return None


# --- Swahili (Kiswahili) deterministic extraction ------------------------
# Spoken Swahili order is action → item → qty → "kwa" → price, with number WORDS
# (hamsini=50, "mia mbili"=200). Lets a Kiswahili voice note log end-to-end.
_SW_UNITS = {"sifuri": 0, "moja": 1, "mbili": 2, "tatu": 3, "nne": 4, "tano": 5,
             "sita": 6, "saba": 7, "nane": 8, "tisa": 9, "kumi": 10}
_SW_TENS = {"ishirini": 20, "thelathini": 30, "arobaini": 40, "hamsini": 50,
            "sitini": 60, "sabini": 70, "themanini": 80, "tisini": 90}
_SW_SCALE = {"mia": 100, "elfu": 1000, "laki": 100000, "milioni": 1000000}
_SW_NUMWORDS = set(_SW_UNITS) | set(_SW_TENS) | set(_SW_SCALE) | {"na"}
_SW_STOP = {"na", "kwa", "kila", "ya", "za", "wa", "la", "ni", "kwenye"}
_SW_VERB_STEMS = ("nunua", "uza", "rudish")


def _sw_words_to_int(tokens):
    """Compose Swahili number words into an int (e.g. ['mia','mbili']→200)."""
    total = 0
    i, n = 0, len(tokens)
    seen = False
    while i < n:
        t = tokens[i]
        if t == "na":
            i += 1
            continue
        if t in _SW_SCALE:
            mult = 1
            if i + 1 < n and tokens[i + 1] in _SW_UNITS and _SW_UNITS[tokens[i + 1]] <= 9:
                mult = _SW_UNITS[tokens[i + 1]]
                i += 1
            total += _SW_SCALE[t] * mult
            seen = True
        elif t in _SW_TENS:
            total += _SW_TENS[t]
            seen = True
        elif t in _SW_UNITS:
            total += _SW_UNITS[t]
            seen = True
        else:
            break
        i += 1
    return total if seen else None


def _grab_number(tokens):
    """Digits win; else the first contiguous run of Swahili number words."""
    for tk in tokens:
        if re.fullmatch(r"\d+(?:\.\d+)?", tk):
            return float(tk)
    run, started = [], False
    for w in tokens:
        if w in _SW_NUMWORDS:
            run.append(w)
            started = True
        elif started:
            break
    v = _sw_words_to_int(run)
    return float(v) if v is not None else None


def extract_swahili(text: str) -> Optional[Dict]:
    """Deterministic Kiswahili extractor. Returns None if not Swahili / not parseable."""
    t = text.lower().strip()
    if "rudish" in t:
        action = "return"
    elif "uza" in t:
        action = "sell"
    elif "nunua" in t:
        action = "buy"
    else:
        return None
    tokens = re.findall(r"[a-z]+|\d+(?:\.\d+)?", t)
    if "kwa" in tokens:
        k = tokens.index("kwa")
        left, right = tokens[:k], tokens[k + 1:]
    else:
        left, right = tokens, []
    qty = _grab_number(left)
    price = _grab_number(right) if right else None
    item_words = [
        w for w in left
        if w.isalpha() and w not in _SW_NUMWORDS and w not in _SW_STOP
        and not any(stem in w for stem in _SW_VERB_STEMS)
    ]
    item = " ".join(item_words[:3]).strip()
    if qty is None or not item:
        return None
    return {
        "action": action, "item": item,
        "quantity": round(qty, 2), "unit_price": round(price if price else 0.0, 2),
        "currency": "KES", "vendor": None,
    }


def extract_via_llm(text: str) -> Optional[Dict]:
    """Fallback: use NIM nemotron-mini-4b-instruct for messy input."""
    if not NIM_API_KEY:
        return None
    try:
        import httpx
        headers = {"Authorization": f"Bearer {NIM_API_KEY}", "Content-Type": "application/json"}
        payload = {
            "model": EXTRACTION_MODEL,
            "messages": [
                {"role": "system", "content": "You are a transaction parser for a small street trader. Extract action (buy/sell/return/refund), item (string), quantity (number), unit_price (number), currency (string), vendor (string, optional). Return ONLY valid JSON. No markdown fences."},
                {"role": "user", "content": text},
            ],
            "max_tokens": 256, "temperature": 0.0,
        }
        with httpx.Client(timeout=30) as client:
            resp = client.post(f"{NIM_BASE}/chat/completions", headers=headers, json=payload)
            resp.raise_for_status()
            raw = resp.json()["choices"][0]["message"]["content"]
        if raw.startswith("```"):
            raw = raw.split("\n", 1)[1].rsplit("\n", 1)[0]
        return json.loads(raw)
    except Exception:
        return None


def parse_transaction(text: str) -> Dict:
    """Strategy: regex first (fast, reliable) → LLM backup (handles messy input)."""
    result = extract_deterministic(text)
    if result:
        add_trace("extraction", method="regex-en", success=True, fields=list(result.keys()))
        return result
    add_trace("extraction", method="regex-en", success=False)
    # Kiswahili deterministic extractor (action→item→qty→kwa→price, number words).
    result = extract_swahili(text)
    if result:
        add_trace("extraction", method="regex-sw", success=True, fields=list(result.keys()))
        return result
    add_trace("extraction", method="regex-sw", success=False)
    result = extract_via_llm(text)
    if result and "error" not in result:
        add_trace("extraction", method="llm", success=True, fields=list(result.keys()))
        return result
    add_trace("extraction", method="llm", success=False)
    return {"error": "Could not parse transaction. Try: 'bought 10 mangoes at 200 shillings'"}


# --- Ledger Operations ----------------------------------------------------

def validate_transaction(tx: Dict) -> Optional[str]:
    """Validate transaction against hard rules."""
    if "error" in tx:
        return tx["error"]
    action = tx.get("action", "").lower()
    if action not in ("buy", "sell", "return", "refund"):
        return f"Unknown action: '{action}'. Must be buy/sell/return/refund."
    qty = tx.get("quantity", 0)
    if not isinstance(qty, (int, float)) or qty <= 0:
        return f"Quantity must be a positive number, got: {qty}"
    price = tx.get("unit_price", 0)
    if not isinstance(price, (int, float)) or price < 0:
        return f"Price must be zero or positive, got: {price}"
    if not tx.get("item", "").strip():
        return "Item name cannot be empty."
    return None


def add_entry(entry: Dict) -> Dict:
    """Add a validated entry to the ledger."""
    entry["timestamp"] = datetime.now().isoformat()
    entry["id"] = len(ledger) + 1
    ledger.append(entry)
    return entry


def calculate_margins() -> Dict:
    """Calculate current P&L from ledger. Pure Python — never the LLM."""
    revenue = 0.0
    costs = 0.0
    inventory: Dict[str, float] = {}
    daily_stats: Dict[str, Dict] = {}
    for entry in ledger:
        action = entry.get("action", "").lower()
        item = str(entry.get("item", "unknown"))
        qty = float(entry.get("quantity", 0))
        price = float(entry.get("unit_price", 0))
        ts = entry.get("timestamp", "")
        day = ts[:10] if ts else "unknown"
        if day not in daily_stats:
            daily_stats[day] = {"revenue": 0, "costs": 0, "transactions": 0}
        daily_stats[day]["transactions"] += 1
        if action in ("buy", "purchase"):
            costs += qty * price
            inventory[item] = inventory.get(item, 0) + qty
        elif action in ("sell", "sale"):
            revenue += qty * price
            inventory[item] = inventory.get(item, 0) - qty
        elif action in ("return", "refund"):
            if entry.get("action", "").lower() == "return":
                costs -= qty * price
                inventory[item] = inventory.get(item, 0) + qty
            else:
                revenue -= qty * price
                inventory[item] = inventory.get(item, 0) + qty

    profit = revenue - costs
    margin_pct = (profit / revenue * 100) if revenue > 0 else 0.0
    item_revenue: Dict[str, float] = {}
    for entry in ledger:
        item = str(entry.get("item", "unknown"))
        total = float(entry.get("quantity", 0)) * float(entry.get("unit_price", 0))
        if entry.get("action", "").lower() in ("sell", "sale"):
            item_revenue[item] = item_revenue.get(item, 0) + total
    top_items = sorted(item_revenue.items(), key=lambda x: x[1], reverse=True)[:5]
    return {
        "revenue": round(revenue, 2), "costs": round(costs, 2),
        "profit": round(profit, 2), "margin_pct": round(margin_pct, 1),
        "transaction_count": len(ledger),
        "inventory": {k: round(v, 1) for k, v in sorted(inventory.items())},
        "top_items": top_items, "days_active": len(daily_stats), "daily_stats": daily_stats,
    }


# --- Voice Input: Nemotron ASR 0.6B (gated — never breaks demo) ----------

# --- Zero GPU ASR: run our fine-tuned Swahili wav2vec2 + Whisper in-Space --------
# HF Inference (serverless) no longer serves these ASR models, so we run them on the
# Space's Zero GPU. `spaces` is only present on HF; import is guarded so local runs
# (and non-GPU hardware) still import the module without error.
try:
    import spaces
    _HAS_SPACES = True
except Exception:
    _HAS_SPACES = False

_ASR_PIPES: Dict[str, object] = {}

def _get_asr_pipe(model_id: str):
    """Lazily build + cache a transformers ASR pipeline (loads on CPU; moved to GPU
    inside the Zero GPU call)."""
    if model_id not in _ASR_PIPES:
        from transformers import pipeline
        _ASR_PIPES[model_id] = pipeline("automatic-speech-recognition", model=model_id)
    return _ASR_PIPES[model_id]

def _run_asr(audio_path: str, model_id: str, language: Optional[str] = None) -> str:
    pipe = _get_asr_pipe(model_id)
    try:
        pipe.model.to("cuda")
    except Exception:
        pass
    kwargs = {}
    # Pin Whisper to the chosen language so it can't mis-detect Swahili as French.
    if "whisper" in model_id.lower() and language in ("sw", "en"):
        kwargs["generate_kwargs"] = {
            "language": {"sw": "swahili", "en": "english"}[language],
            "task": "transcribe",
        }
    out = pipe(audio_path, **kwargs)
    return (out.get("text") if isinstance(out, dict) else str(out)).strip()

# Decorate for Zero GPU when running on HF (no-op otherwise).
if _HAS_SPACES:
    _run_asr = spaces.GPU(duration=300)(_run_asr)


def transcribe_audio(audio_path: str, language: str = "auto") -> Optional[str]:
    """Transcribe in-Space on Zero GPU, routed by language. Gated — never breaks the demo.

    Swahili uses our own fine-tuned, published model (Well-Tuned); English/auto uses
    Whisper. Both run on the Space's Zero GPU. Any failure degrades to 'type instead'.
    """
    if not audio_path:
        return None
    SW_MODEL = os.environ.get(
        "ASR_SW_MODEL", "Joshua-Abok/finetuning-wav2vec-large-swahili-asr-model_v12")
    EN_MODEL = os.environ.get("ASR_EN_MODEL", "openai/whisper-small")  # fast on a GPU slice
    if language == "sw":
        order = [SW_MODEL, EN_MODEL]
    elif language == "en":
        order = [EN_MODEL]
    else:  # auto
        order = [EN_MODEL, SW_MODEL]
    hint = language if language in ("sw", "en") else None
    for model in order:
        try:
            text = _run_asr(audio_path, model, hint)
            if text:
                add_trace("asr", method=model, success=True)
                return text
        except Exception as e:
            add_trace("asr", method=model, success=False, error=str(e)[:80])
            continue
    return None


def generate_speech(text: str) -> Optional[bytes]:
    """Generate speech via NVIDIA Nemotron TTS. Fails silently."""
    if not text or not NIM_API_KEY:
        return None
    try:
        import httpx
        headers = {"Authorization": f"Bearer {NIM_API_KEY}", "Content-Type": "application/json"}
        payload = {"model": "nvidia/nemotron-tts-1b", "text": text}
        with httpx.Client(timeout=30) as client:
            resp = client.post(f"{NIM_BASE}/tts/generate", headers=headers, json=payload)
            resp.raise_for_status()
            add_trace("tts", method="nemotron-tts-1b", success=True)
            return resp.content
    except Exception as e:
        add_trace("tts", method="nemotron-tts-1b", success=False, error=str(e)[:80])
        return None


# --- Advisory -------------------------------------------------------------

def get_deterministic_advice() -> str:
    """Rule-based advisory from ledger numbers."""
    m = calculate_margins()
    parts = []
    if m["transaction_count"] == 0:
        return "📊 Add your first transaction to get started! Example: 'bought 10 mangoes at 200 shillings'"
    if m["transaction_count"] < 3:
        parts.append(f"📊 {m['transaction_count']} transaction(s) logged. Keep going!")
        if m["top_items"]:
            parts.append(f"📦 Top item: {m['top_items'][0][0]}")
        return " ".join(parts)
    parts.append(f"📊 Revenue: {m['revenue']:.0f} | Costs: {m['costs']:.0f} | Profit: {m['profit']:.0f}")
    if m["profit"] > 0:
        parts.append(f"✅ You're making a {m['margin_pct']:.1f}% margin. Good work!")
    elif m["profit"] < 0:
        parts.append(f"⚠️ You're losing {abs(m['profit']):.0f}. Check your costs!")
    else:
        parts.append("⚖️ Breaking even — look for ways to increase prices or reduce costs.")
    if m["top_items"]:
        parts.append(f"💰 Your best seller: {m['top_items'][0][0]} ({m['top_items'][0][1]:.0f} total)")
    low_stock = [item for item, qty in m["inventory"].items() if qty < 0]
    if low_stock:
        parts.append(f"🚨 {', '.join(low_stock)} are oversold/out of stock!")
    if m["days_active"] >= 2:
        parts.append(f"📅 You've been tracking {m['days_active']} days. Consistency builds business!")
    return "\n".join(parts)


async def get_modal_advisory():
    """Get AI advisory from Modal vLLM. Falls back to deterministic if unavailable."""
    if not MODAL_BASE:
        return get_deterministic_advice()
    try:
        m = calculate_margins()
        prompt = f"""You are a helpful bookkeeping assistant for a small street trader named Mama Aisha.

Current financial summary:
- Revenue: {m['revenue']:.0f} | Costs: {m['costs']:.0f} | Profit: {m['profit']:.0f}
- Margin: {m['margin_pct']:.1f}% | Transactions: {m['transaction_count']}
- Inventory: {m['inventory']}

Provide concise, actionable advice. 2-3 sentences max. Street-smart."""
        payload = {
            "model": ADVISORY_MODEL,
            "messages": [{"role": "user", "content": prompt}],
            "max_tokens": 512, "temperature": 0.7,
        }
        import httpx
        async with httpx.AsyncClient(timeout=30) as client:
            resp = await client.post(f"{MODAL_BASE}/chat/completions", json=payload)
            resp.raise_for_status()
            return resp.json()["choices"][0]["message"]["content"]
    except Exception as e:
        logging.warning(f"Modal advisory failed: {e}")
        add_trace("advisory", method="modal", success=False, error=str(e))
        return get_deterministic_advice()


# --- Custom Ledger UI (HTML for Off Brand badge) --------------------------

def format_ledger() -> str:
    """Format ledger as styled HTML table."""
    if not ledger:
        return '<p class="empty">No transactions yet. Try: "bought 50 mangoes at 200 shillings"</p>'
    html = '<table class="ledger"><thead><tr>'
    html += '<th>#</th><th>Time</th><th>Action</th><th>Item</th><th>Qty</th><th>Price</th><th>Total</th><th>Currency</th>'
    html += '</tr></thead><tbody>'
    for e in ledger:
        action = e.get("action", "")
        item = e.get("item", "")
        qty = e.get("quantity", 0)
        price = e.get("unit_price", 0)
        total = qty * price
        currency = e.get("currency", "")
        ts = e.get("timestamp", "")[:16]
        html += '<tr><td>{}</td><td>{}</td><td>{}</td><td>{}</td><td>{:.1f}</td><td>{:.2f}</td><td>{:.2f}</td><td>{}</td></tr>'.format(e["id"], ts, action, item, qty, price, total, currency)
    html += '</tbody></table>'
    return html


def format_margins() -> str:
    """Format margins as styled HTML block with color coding."""
    m = calculate_margins()
    if m["transaction_count"] == 0:
        return '<p>Add transactions to see your margins.</p>'
    if m["profit"] > 0:
        color, icon, bg = "#2E7D32", "✅", "rgba(46,125,50,0.04)"
    elif m["profit"] < 0:
        color, icon, bg = "#C62828", "⚠️", "rgba(198,40,40,0.04)"
    else:
        color, icon, bg = "#F57C00", "⚖️", "rgba(245,124,0,0.04)"
    inv_items = list(m["inventory"].items())
    inv_str = ", ".join("{}={}".format(k, v) for k, v in inv_items[:6])
    if len(inv_items) > 6:
        inv_str += " (+{} more)".format(len(inv_items) - 6)
    return '<div style="color: {}; padding: 14px; border-radius: 10px; border: 1px solid {}; background: {}; font-family: inherit;">'.format(color, color + "22", bg) + \
        '<p style="margin: 4px 0;"><b>{}</b> Revenue: {:.0f}</p>'.format(icon, m["revenue"]) + \
        '<p style="margin: 4px 0;"><b>Costs:</b> {:.0f}</p>'.format(m["costs"]) + \
        '<p style="margin: 4px 0;"><b>Profit:</b> {:.0f}</p>'.format(m["profit"]) + \
        '<p style="margin: 4px 0;"><b>Margin:</b> {:.1f}%</p>'.format(m["margin_pct"]) + \
        '<p style="margin: 4px 0;"><b>Transactions:</b> {} | <b>Days:</b> {}</p>'.format(m["transaction_count"], m["days_active"]) + \
        '<p style="margin: 4px 0; font-size: 12px; color: #666;">Inventory: {}</p>'.format(inv_str) + \
        '</div>'


CSS = """
.ledger table { width: 100%; border-collapse: collapse; }
.ledger th, .ledger td { padding: 8px 10px; border: 1px solid #ddd; text-align: left; font-size: 13px; }
.ledger th { background: #2E7D32; color: white; font-weight: 600; }
.ledger tr:nth-child(even) { background: #fafafa; }
.ledger tr:hover { background: #f0f7f0; }
.empty { color: #888; font-style: italic; font-size: 14px; }
.voice-status { font-size: 12px; color: #666; margin-top: 4px; }
"""


def process_transaction(text: str, state: Dict):
    """Process a natural language transaction."""
    if not text.strip():
        return state, "Please enter a transaction.", format_ledger(), format_margins()
    parsed = parse_transaction(text)
    error = validate_transaction(parsed)
    if error:
        add_trace("validation", success=False, error=error)
        return state, "❌ {}".format(error), format_ledger(), format_margins()
    entry = add_entry(parsed)
    state["ledger"] = ledger
    status = "✅ {} {}x {} @ {} {}".format(
        entry.get('action', '?'), entry.get('quantity', '?'),
        entry.get('item', '?'), entry.get('unit_price', '?'),
        entry.get('currency', ''))
    if entry.get("vendor"):
        status += " from {}".format(entry["vendor"])
    return state, status, format_ledger(), format_margins()


def process_voice(audio_path: str, language: str, state: Dict):
    """Process voice input (English/Swahili) — gated so it never crashes the demo."""
    if not audio_path:
        return state, "Record and upload audio to use voice input.", format_ledger(), format_margins()
    lang = {"English": "en", "Swahili": "sw", "Auto": "auto"}.get(language, "auto")
    try:
        text = transcribe_audio(audio_path, language=lang)
        if not text:
            notice = "🎤 Voice unavailable — please type your transaction instead."
            add_trace("voice", success=False, reason="no_transcription")
            return state, notice, format_ledger(), format_margins()
        parsed = parse_transaction(text)
        error = validate_transaction(parsed)
        if error:
            add_trace("voice", success=False, reason="validation", error=error)
            return state, "🎤 Heard: \"{}\"\n\n❌ {}".format(text, error), format_ledger(), format_margins()
        entry = add_entry(parsed)
        state["ledger"] = ledger
        status = "🎤 Heard ({}): \"{}\"\n\n✅ {} {}x {} @ {} {}".format(
            lang, text, entry.get('action', '?'), entry.get('quantity', '?'),
            entry.get('item', '?'), entry.get('unit_price', '?'),
            entry.get('currency', ''))
        if entry.get("vendor"):
            status += " from {}".format(entry["vendor"])
        return state, status, format_ledger(), format_margins()
    except Exception as e:
        add_trace("voice", success=False, reason="exception", error=str(e)[:80])
        return state, "🎤 Voice unavailable — please type your transaction instead.", format_ledger(), format_margins()


def get_ai_advice(state: Dict):
    """Get AI advisory (Modal → deterministic fallback)."""
    if not ledger:
        return "📊 Add some transactions first! Try: 'bought 10 onions at 50 shillings'"
    try:
        import asyncio
        loop = asyncio.get_event_loop()
        return loop.run_until_complete(get_modal_advisory())
    except Exception:
        return get_deterministic_advice()


def get_traces():
    """Return latest 20 agent traces."""
    if not agent_traces:
        return "No traces yet. Start logging transactions!"
    recent = agent_traces[-20:]
    lines = []
    for t in recent:
        lines.append("{} | {} | {} | {}".format(
            t.get('ts', '')[:19], t['step'], t.get('method', '?'), t.get('success', '?')))
    return "\n".join(lines)


# --- Build Gradio interface -----------------------------------------------
import gradio as gr

with gr.Blocks(title="Sidewalk FM — Mama Aisha's Ledger") as demo:
    gr.Markdown("""
    # 📊 Sidewalk FM — Leja ya Mama Aisha / Mama Aisha's Ledger

    *Msaidizi wa hesabu kwa Mama Aisha, mfanyabiashara wa sokoni.*
    *A bookkeeping assistant for Mama Aisha, a morning-market produce trader.*

    **Andika au sema** muamala wako — **kwa Kiswahili au Kiingereza.** Hesabu ni sahihi kila wakati.
    Track buys, sells & margins by **voice or text, in Swahili or English.**
    Powered by **NVIDIA Nemotron Mini 4B** (advice) + our **fine-tuned Kiswahili ASR** — Tiny Titan + Well-Tuned.

    **Mifano / Examples:**
    - 🇰🇪 *"nimenunua maembe hamsini kwa mia mbili"*  (bought 50 mangoes at 200)
    - 🇬🇧 *"sold 30 maize for 1500"*
    - *"return 5 broken tomatoes" / "rudisha nyanya tano"*
    """)

    with gr.Row():
        with gr.Column(scale=2):
            tx_input = gr.Textbox(
                label="Muamala / Transaction (sema kwa lugha yako)",
                placeholder="nimenunua maembe hamsini kwa mia mbili  /  bought 50 mangoes at 200",
                lines=2,
            )
            tx_btn = gr.Button("📝 Ongeza / Add Transaction", variant="primary")
            tx_status = gr.Markdown("Add a transaction above...")

            gr.HTML("<hr>")
            
            gr.Markdown("### 🎤 Voice Input — English & Kiswahili")
            gr.Markdown("*Pick a language, click the mic, speak your transaction, then press Record & Add.*")
            lang_dropdown = gr.Dropdown(
                choices=["Auto", "English", "Swahili"],
                value="Auto",
                label="Language (Lugha) — Swahili uses our fine-tuned model 🏅",
            )
            audio_input = gr.Audio(
                label="Record your transaction",
                type="filepath",
                sources=["microphone"],
            )
            voice_btn = gr.Button("🎙️ Rekodi / Record & Add", variant="secondary")
            voice_notice = gr.Markdown("Voice input ready", elem_classes=["voice-status"])

        with gr.Column(scale=1):
            advice_btn = gr.Button("💡 Ushauri / Get Advice", variant="secondary")
            advice_out = gr.Markdown("Add transactions, then click for advice!")

    gr.HTML(label="Margins")
    margins_display = gr.HTML(label="Margins")

    with gr.Tabs():
        with gr.TabItem("Leja / Ledger"):
            ledger_display = gr.HTML(label="Transaction Ledger")
        
        with gr.TabItem("Agent Traces"):
            trace_display = gr.Textbox(label="Structured Agent Traces (📡)", lines=8, interactive=False)

    state = gr.State({"ledger": []})

    tx_btn.click(process_transaction, inputs=[tx_input, state],
                 outputs=[state, tx_status, ledger_display, margins_display])
    voice_btn.click(process_voice, inputs=[audio_input, lang_dropdown, state],
                    outputs=[state, tx_status, ledger_display, margins_display])
    advice_btn.click(get_ai_advice, inputs=[state], outputs=[advice_out])
    trace_display.change(get_traces, outputs=[trace_display])
    demo.load(lambda: {"ledger": []}, outputs=[state])


if __name__ == "__main__":
    theme = gr.themes.Soft(primary_hue="green")
    demo.launch(server_name="0.0.0.0", server_port=7860, share=False, theme=theme, css=CSS)