src/gujarati_processor.py

"""
gujarati_processor.py — Gujarati Language Post-Processor for Maya

THREE FUNCTIONS:
  1. correct_transcript(text) — fixes common STT errors in Gujarati
  2. add_natural_fillers(text) — adds human-like filler words to TTS output
  3. build_gujarati_system_prompt_addon() — returns the code-mixing
     instruction block to append to Maya's system prompt
"""

import re
import random
from typing import Optional


# ── TRANSCRIPT CORRECTIONS ────────────────────────────────────────────────────

TRANSCRIPT_CORRECTIONS = {
    # Phone call context misheard words
    r"\bshoe\b":        "shu",        # "shu" (what) heard as "shoe"
    r"\bkhem cho\b":    "kem cho",    # greeting
    r"\bchem cho\b":    "kem cho",
    r"\bkal\b(?= [a-z])": "kal",     # "kal" (tomorrow) — keep as-is
    r"\bcall\b(?= [a-z])": "kal",    # Sarvam mishears "kal" as "call" sometimes

    # Common appointment/dental vocabulary
    r"\bapoinment\b":   "appointment",
    r"\bapointment\b":  "appointment",
    r"\bdocter\b":      "doctor",
    r"\bdenter\b":      "dentist",
    r"\bcleeaning\b":   "cleaning",
    r"\bclining\b":     "cleaning",

    # Time expressions — Sarvam sometimes transcribes these wrong
    r"\bbaze\b":        "baje",       # "baje" (o'clock in Gujarati)
    r"\bbaj\b(?=\s)":   "baje",
    r"\bvagye\b":       "vage",       # "vage" (o'clock variant)
    r"\bvaagye\b":      "vage",

    # Name of Ahmedabad localities (commonly mispronounced)
    r"\bvastrar\b":     "Vastrapur",
    r"\bsatelite\b":    "Satellite",
    r"\bnavrang\b":     "Navrangpura",
    r"\bnaranpur\b":    "Naranpura",

    # Gujarati filler words Sarvam sometimes misses
    r"\bhan\b":         "haa",        # "haa" (yes/okay)
    r"\bthik\b":        "theek",      # "theek" (okay)
}


def correct_transcript(text: str) -> str:
    if not text:
        return text

    corrected = text
    for pattern, replacement in TRANSCRIPT_CORRECTIONS.items():
        corrected = re.sub(pattern, replacement, corrected, flags=re.IGNORECASE)

    return corrected


# ── NATURAL GUJARATI FILLERS ──────────────────────────────────────────────────

GUJARATI_FILLERS = [
    "Juo, ",           # "Look, " — very natural in Gujarati
    "Haa, ",           # "Yes, " — affirmative opener
    "Acha, ",          # "Okay, " — acknowledgment
    "Bilkul, ",        # "Absolutely, "
    "Theek chhe, ",    # "That's fine, "
    "Samjhi gayi, ",   # "I understand, " (Maya referring to herself)
]

HINDI_FILLERS = [
    "Jee, ",           # "Yes, "
    "Haan, ",          # "Yes/Okay"
    "Achha, ",         # "Okay"
    "Bilkul, ",        # "Absolutely"
    "Theek hai, ",     # "That's fine"
    "Samajh gayi, ",   # "I understand"
]

ENGLISH_FILLERS = [
    "Sure, ",
    "Of course, ",
    "Absolutely, ",
    "Got it, ",
    "I see, ",
]

FILLER_MAP = {
    "gujarati": GUJARATI_FILLERS,
    "hindi":    HINDI_FILLERS,
    "english":  ENGLISH_FILLERS,
}

# Words that already start the response naturally — don't add filler before these
NATURAL_STARTERS = [
    # Gujarati
    "Namaste", "Haa", "Juo", "Acha", "Bilkul", "Theek", "Samjhi",
    "3", "4", "5", "6",   # Don't add filler before times/numbers
    "kal", "aaj", "parso",
    # Hindi
    "Namaste", "Haan", "Achha", "Bilkul",
    # English
    "Hello", "Sure", "Of course", "Yes", "No", "I",
    # Empathy openers from E2 — already natural
    "Mane", "Hu samjhi", "Maaf", "Juo samjho",
]


def add_natural_fillers(
    text:     str,
    language: str = "gujarati",
    probability: float = 0.35,
) -> str:
    if not text or len(text) < 15:
        return text

    # Don't add filler to already-natural openers
    for starter in NATURAL_STARTERS:
        if text.startswith(starter):
            return text

    # Don't add filler before pure questions
    if text.strip().endswith("?") and len(text.split()) < 8:
        return text

    # Probabilistic application
    if random.random() >= probability:
        return text

    fillers = FILLER_MAP.get(language, FILLER_MAP["gujarati"])
    chosen  = random.choice(fillers)

    # Lowercase the first letter of original text after filler
    if text and text[0].isupper() and not text[:2].isupper():
        text = text[0].lower() + text[1:]

    return chosen + text


# ── SYSTEM PROMPT ADDON ───────────────────────────────────────────────────────

def build_gujarati_system_prompt_addon() -> str:
    return """

GUJARATI LANGUAGE STYLE — MANDATORY RULES:

You are speaking CONVERSATIONAL Gujarati on a phone call.
Real Gujarati speakers mix Gujarati grammar with English nouns.
This is called "code-mixing" and it sounds completely natural.

CORRECT examples of how to respond:
  ✅ "Haa, appointment available chhe. Tamaro naam shu chhe?"
  ✅ "3 baje slot chhe. Chaleshe?"
  ✅ "Ek minute, check karu chhu."
  ✅ "Doctor sathe consultation ₹200 chhe."
  ✅ "OK, booking confirm thi gayi."
  ✅ "Maafi maango, 3 baje busy chhe. 4 baje available chhe?"

WRONG — never say these (too formal, nobody speaks like this):
  ❌ "Haa, niyuktisthan upalabdh chhe. Tamaro naam shu chhe?"
  ❌ "Trann vage ni jagya chhe. Svikar karso?"
  ❌ "Ek pal, parischay karu chhu."
  ❌ "Vaidya sathe paramarsh ₹200 chhe."
  ❌ "Theek, pratishtha nischit thi gayi."

GRAMMAR RULES for natural Gujarati:
  - Use Gujarati verb endings: "chhe", "chhu", "karu", "karso", "thi gayi"
  - Use English nouns directly: "appointment", "doctor", "booking", "slot"
  - Use English numbers with Gujarati time: "3 baje", "4 vage", "10 minute"
  - Short sentences only. Maximum 10 words per sentence.
  - Never use long Sanskrit-derived Gujarati compound words.
  - Say "check karu chhu" not "thaapan karu chhu"
  - Say "confirm thi gayi" not "nischit thi gayi"
  - Say "available chhe" not "upalabdh chhe"

RESPONSE LENGTH:
  Phone call responses must be SHORT.
  Maximum 2 sentences per response.
  If the answer is one sentence — use ONE sentence.
  Do not add pleasantries or padding.

FILLER SOUNDS (already handled by code — do NOT add these in your text):
  The system adds "Juo,", "Haa,", "Acha," automatically.
  Do not start responses with filler words yourself.
""".strip()


def build_hindi_system_prompt_addon() -> str:
    return """

HINDI LANGUAGE STYLE — MANDATORY RULES:

Conversational Hindi on a phone call. Mix Hindi grammar with English nouns.

CORRECT examples:
  ✅ "Haan, appointment available hai. Aapka naam kya hai?"
  ✅ "3 baje slot hai. Chalega?"
  ✅ "Ek minute, check karti hoon."
  ✅ "Doctor ke saath consultation ₹200 hai."
  ✅ "OK, booking confirm ho gayi."

WRONG (too formal):
  ❌ "Haan, niyukti upalabdh hai."
  ❌ "Tin baje ka sthan hai."

SHORT RESPONSES ONLY. Maximum 2 sentences. Max 10 words per sentence.
""".strip()