core/model_config.py

# core/model_config.py

from dataclasses import dataclass

# UI mock mode — DISABLED for the published Hugging Face Space (always uses the real
# Modal-served models). The core wrappers keep a mock branch for offline UI dev; set
# this True locally to use canned story/audio without calling Modal. Keep False here.
UI_MOCK: bool = False

# ─────────────────────────────────────────────
#  ACTIVE STACK — Stack A is the sole submission stack (OpenBMB prize path).
#  The StackConfig machinery below is kept so a stack could be added/swapped, but
#  only "A" is defined; Stacks B/C were dropped.
ACTIVE_STACK: str = "A"
# ─────────────────────────────────────────────
#  WHERE INFERENCE RUNS
#  "modal" → models served on Modal cloud GPUs (current; see CLAUDE.md infra note)
#  "local" → models served on the local machine (legacy offline path; unsupported)
COMPUTE_LOCATION: str = "modal"
#  Modal GPU tier for inference containers. A10G (24 GB) covers Stack A's runtime.
MODAL_GPU: str = "A10G"
#  Keep one container warm to hide cold starts. =1 during a demo (no cold start,
#  but bills idle GPU — incl. the A100 FT-serve container, so revert to 0 after).
#  =0 scales to zero and only bills per request (cold start ~3-5 min on first call).
MODAL_MIN_CONTAINERS: int = 0
# ─────────────────────────────────────────────


@dataclass(frozen=True)
class StackConfig:
    name: str
    description: str
    vision_model: str          # Ollama model tag
    vision_backend: str        # "ollama" (all stacks use Ollama)
    stt_model: str             # faster-whisper model size
    stt_bn_model: str | None   # optional Bengali-specific STT model (HF repo)
    tts_en_backend: str        # "voxcpm2"
    tts_bn_backend: str        # "indic_tts" (chosen) | "indic_parler" (alt)
    tts_bn_ref_audio: str | None  # unused (was for the removed IndicF5 voice-clone)
    total_params_b: float      # informational — for README generation
    openbmb_prize_eligible: bool


STACKS: dict[str, StackConfig] = {
    "A": StackConfig(
        name="Stack A — OpenBMB Prize Path",
        description="MiniCPM-V 4.5 + VoxCPM2 + AI4Bharat Indic-TTS. ~12.4B. OpenBMB prize eligible.",
        # Default (~Q4, 6.1GB). q8_0 was tested and gave NO Bengali quality gain at
        # higher cost/latency — precision is not the bottleneck, the 8B model's
        # Bengali capability is. Bengali quality is addressed via two-pass (Lever C).
        vision_model="openbmb/minicpm-v4.5",
        vision_backend="ollama",
        stt_model="large-v3",
        stt_bn_model="bangla-asr/whisper-medium-bn",
        tts_en_backend="voxcpm2",
        # Bengali TTS: AI4Bharat Indic-TTS (FastPitch). Chosen over Indic Parler-TTS
        # (sounded artificial) and IndicF5 (voice clone — removed: too slow even on
        # A100, needs a reference clip). FastPitch is fast, no reference needed.
        tts_bn_backend="indic_tts",
        tts_bn_ref_audio=None,
        total_params_b=12.4,
        openbmb_prize_eligible=True,
    ),
}


def get_config() -> StackConfig:
    """Returns the active stack config. Import this everywhere model details are needed."""
    if ACTIVE_STACK not in STACKS:
        raise ValueError(
            f"ACTIVE_STACK='{ACTIVE_STACK}' is not valid. Stack A is the only defined stack."
        )
    return STACKS[ACTIVE_STACK]


def get_all_stacks() -> dict[str, StackConfig]:
    """Returns all defined stacks (currently just Stack A)."""
    return STACKS


# HF repo IDs for the TTS backends. Model names live ONLY in this file — the
# StackConfig stores the backend *key* ('voxcpm2' | 'indic_parler' | 'indic_tts');
# this maps that key to the actual repo passed to core/modal_infra.py.
TTS_BACKEND_REPOS: dict[str, str] = {
    "voxcpm2": "openbmb/VoxCPM2",            # English (Voice Design)
    "indic_parler": "ai4bharat/indic-parler-tts",
    # AI4Bharat Indic-TTS (FastPitch + HiFi-GAN) — no HF repo; the value is the
    # GitHub-release checkpoint zip (per-language). Bengali = bn.zip (~1.5 GB).
    # Dedicated, MOS-tuned, no reference clip; fixed voice (no persona control).
    "indic_tts": "https://github.com/AI4Bharat/Indic-TTS/releases/download/v1-checkpoints-release/bn.zip",
}


def get_tts_repo(backend: str) -> str:
    """Resolve a TTS backend key to its HuggingFace repo ID."""
    try:
        return TTS_BACKEND_REPOS[backend]
    except KeyError:
        raise ValueError(
            f"Unknown TTS backend '{backend}'. Known: {list(TTS_BACKEND_REPOS)}"
        )


# Per-language decoding params for the vision/story model (passed to Ollama).
# Bengali uses a more conservative profile: lower temperature + min_p floor +
# repetition penalty suppress the wrong-script (Latin) tokens, invented non-words,
# and phrase repetition that high-temperature sampling produces in a lower-resource
# language. English can afford a livelier profile. Tune these here only.
VISION_GEN_OPTIONS: dict[str, dict] = {
    "en": {
        "temperature": 0.8,
        "top_p": 0.95,
        "repeat_penalty": 1.1,
        "num_predict": 500,  # bound the response; a bedtime story is short
    },
    "bn": {
        "temperature": 0.45,
        "top_p": 0.9,
        "top_k": 40,
        "min_p": 0.05,
        "repeat_penalty": 1.18,
        "repeat_last_n": 64,
        "num_predict": 700,  # Bengali uses more tokens per word; still bounded
    },
}


def get_vision_options(language: str) -> dict:
    """Return a copy of the decoding params for the given language ('en'|'bn')."""
    return dict(VISION_GEN_OPTIONS.get(language, VISION_GEN_OPTIONS["en"]))


# Translation-pivot path (research option #1): MiniCPM writes the story in English
# (its strength), then IndicTrans2 translates it to fluent Bengali. Model name lives
# here only. 1B (gated, MIT) for quality; dist-200M is the faster/smaller option.
TRANSLATION_MODEL = "ai4bharat/indictrans2-en-indic-1B"
# IndicTrans2 FLORES-style language codes.
INDICTRANS_LANG_CODES: dict[str, str] = {"en": "eng_Latn", "bn": "ben_Beng"}


def get_indictrans_code(language: str) -> str:
    """Map our 'en'/'bn' codes to IndicTrans2's FLORES codes."""
    try:
        return INDICTRANS_LANG_CODES[language]
    except KeyError:
        raise ValueError(f"No IndicTrans2 code for language '{language}'.")


# ── Bengali distillation fine-tuning (see finetune/) ────────────────────────
# Teacher that writes native Bengali story labels from a drawing. Gemma 3 is
# multimodal and writes excellent Bengali (চাঁদমামা/পুকুর register). 27B gives the
# best labels (fewer code-switch leaks); 12B is faster. Label quality caps the
# student, and data-gen is a one-time job, so quality is prioritised here.
TEACHER_MODEL = "gemma3:27b"
# Base student that gets fine-tuned (the Stack A vision model, HF repo form for
# training — Ollama tag form for serving is in the StackConfig).
STUDENT_BASE_REPO = "openbmb/MiniCPM-V-4_5"
# Once a LoRA is trained + merged and served via vLLM, set this to the merged
# model path/repo and route the vision path to it. None = use the base model.
# Set 2026-06-13 after the held-out eval (finetune/eval_ft.py): the fine-tuned
# model decisively beats the base on Bengali (base output was garbled + looping;
# FT is coherent native রূপকথা), confirmed by a Bengali speaker. Bengali now routes
# to the FT model served by finetune/serve_vllm.py (app `rupkotha-ft-serve`).
FINETUNED_VISION_MODEL: str | None = "/data/out/minicpm-v-bengali-merged"


def get_compute() -> dict:
    """Returns the active compute-location settings (Modal infra). Import this in
    core/modal_infra.py and the core/ wrappers — never hardcode GPU tier or location."""
    if COMPUTE_LOCATION not in ("modal", "local"):
        raise ValueError(f"COMPUTE_LOCATION='{COMPUTE_LOCATION}' is not valid. Use 'modal' or 'local'.")
    return {
        "location": COMPUTE_LOCATION,
        "gpu": MODAL_GPU,
        "min_containers": MODAL_MIN_CONTAINERS,
    }