config.py

"""
config.py
─────────
Centralised configuration loader.

All settings are read from environment variables (populated from the .env
file via python-dotenv).  Sensible defaults are provided where possible so
the module never raises at import time — validation errors surface only when
you call `get_config()`.
"""

from __future__ import annotations

import logging
import os
from dataclasses import dataclass, field
from pathlib import Path
from typing import List

from dotenv import load_dotenv

# Load .env from the project root (the directory that contains this file).
load_dotenv(dotenv_path=Path(__file__).parent / ".env", override=False)


# ─────────────────────────────────────────────────────────────────────────────
# Data-class that holds the entire runtime configuration
# ─────────────────────────────────────────────────────────────────────────────

@dataclass
class Config:
    # ── Telegram API ──────────────────────────────────────────────────────────
    api_id: int
    api_hash: str
    phone_number: str

    # ── Channels ──────────────────────────────────────────────────────────────
    source_channels: List[str]      # usernames or numeric IDs as strings
    destination_channel: str        # username or numeric ID

    # ── Session ───────────────────────────────────────────────────────────────
    session_name: str = "monitor_bot"

    # ── Paths ─────────────────────────────────────────────────────────────────
    temp_dir: Path = field(default_factory=lambda: Path("./temp_media"))
    db_path: Path = field(default_factory=lambda: Path("./processed_messages.db"))

    # ── Groq AI ───────────────────────────────────────────────────────────────
    groq_api_key: str = ""            # required when ai_enabled=True
    ai_enabled: bool = True            # set False to bypass all AI processing
    similarity_threshold: float = 0.80 # duplicate-detection threshold (0–1)
    recent_news_window: int = 200      # sliding window size (# of recent items)

    # ── Hugging Face persistent store (optional, replaces SQLite on Render) ──
    hf_token: str = ""                 # HF write token (Settings → Access Tokens)
    hf_dataset_repo: str = ""          # e.g. "yourname/pepbielsa-processed"
    hf_push_every: int = 20            # push to HF every N marks

    # ── Session String (for Render/cloud deployments) ─────────────────────────
    session_string: str = ""           # export once with session_export.py

    # ── Logging ───────────────────────────────────────────────────────────────
    log_level: str = "INFO"

    def __post_init__(self) -> None:
        # Ensure directories exist at startup.
        self.temp_dir.mkdir(parents=True, exist_ok=True)


# ─────────────────────────────────────────────────────────────────────────────
# Helper — parse comma-separated channel list
# ─────────────────────────────────────────────────────────────────────────────

def _parse_channels(raw: str) -> List[str]:
    """Split a comma-separated string into a clean list of channel identifiers.

    Each element is stripped of whitespace.  Numeric IDs are returned as
    strings so callers can decide whether to cast them.
    """
    return [ch.strip() for ch in raw.split(",") if ch.strip()]


# ─────────────────────────────────────────────────────────────────────────────
# Public factory
# ─────────────────────────────────────────────────────────────────────────────

def get_config() -> Config:
    """Build and return a validated :class:`Config` instance.

    Raises
    ------
    ValueError
        If any *required* environment variable is missing or invalid.
    """
    errors: List[str] = []

    # ── Required fields ───────────────────────────────────────────────────────
    raw_api_id = os.getenv("API_ID", "")
    try:
        api_id = int(raw_api_id)
    except ValueError:
        errors.append(f"API_ID must be an integer, got: {raw_api_id!r}")
        api_id = 0  # placeholder so we can collect more errors

    api_hash = os.getenv("API_HASH", "")
    if not api_hash:
        errors.append("API_HASH is required.")

    phone_number = os.getenv("PHONE_NUMBER", "")
    if not phone_number:
        errors.append("PHONE_NUMBER is required.")

    destination_channel = os.getenv("DESTINATION_CHANNEL", "")
    if not destination_channel:
        errors.append("DESTINATION_CHANNEL is required.")

    raw_sources = os.getenv("SOURCE_CHANNELS", "")
    source_channels = _parse_channels(raw_sources)
    if not source_channels:
        errors.append(
            "SOURCE_CHANNELS is required. Provide a comma-separated list of "
            "channel usernames or numeric IDs."
        )

    if errors:
        raise ValueError(
            "Configuration errors found:\n  • " + "\n  • ".join(errors)
        )

    # ── Optional fields (with defaults) ───────────────────────────────────────
    session_name = os.getenv("SESSION_NAME", "monitor_bot")
    log_level = os.getenv("LOG_LEVEL", "INFO").upper()
    temp_dir = Path(os.getenv("TEMP_DIR", "./temp_media"))
    db_path = Path(os.getenv("DB_PATH", "./processed_messages.db"))

    # ── Groq AI (optional, but required when AI_ENABLED=true) ────────────────
    ai_enabled_str = os.getenv("AI_ENABLED", "true").lower()
    ai_enabled = ai_enabled_str not in ("false", "0", "no", "off")
    groq_api_key = os.getenv("GROQ_API_KEY", "")
    if ai_enabled and not groq_api_key:
        errors.append(
            "GROQ_API_KEY is required when AI_ENABLED=true. "
            "Get a free key (no credit card) at https://console.groq.com "
            "or set AI_ENABLED=false to disable AI features."
        )

    try:
        similarity_threshold = float(os.getenv("SIMILARITY_THRESHOLD", "0.80"))
        if not 0.0 <= similarity_threshold <= 1.0:
            raise ValueError()
    except ValueError:
        errors.append("SIMILARITY_THRESHOLD must be a float between 0.0 and 1.0.")
        similarity_threshold = 0.80

    try:
        recent_news_window = int(os.getenv("RECENT_NEWS_WINDOW", "200"))
        if recent_news_window < 1:
            raise ValueError()
    except ValueError:
        errors.append("RECENT_NEWS_WINDOW must be a positive integer.")
        recent_news_window = 200

    if errors:
        raise ValueError(
            "Configuration errors found:\n  • " + "\n  • ".join(errors)
        )

    # ── Hugging Face (optional) ───────────────────────────────────────────────
    hf_token = os.getenv("HF_TOKEN", "")
    hf_dataset_repo = os.getenv("HF_DATASET_REPO", "")
    try:
        hf_push_every = int(os.getenv("HF_PUSH_EVERY", "20"))
    except ValueError:
        hf_push_every = 20

    # ── Session String (cloud deployments) ────────────────────────────────────
    session_string = os.getenv("SESSION_STRING", "")

    if errors:
        raise ValueError(
            "Configuration errors found:\n  • " + "\n  • ".join(errors)
        )

    return Config(
        api_id=api_id,
        api_hash=api_hash,
        phone_number=phone_number,
        source_channels=source_channels,
        destination_channel=destination_channel,
        session_name=session_name,
        log_level=log_level,
        temp_dir=temp_dir,
        db_path=db_path,
        groq_api_key=groq_api_key,
        ai_enabled=ai_enabled,
        similarity_threshold=similarity_threshold,
        recent_news_window=recent_news_window,
        hf_token=hf_token,
        hf_dataset_repo=hf_dataset_repo,
        hf_push_every=hf_push_every,
        session_string=session_string,
    )


# ─────────────────────────────────────────────────────────────────────────────
# Logging setup (called once from main.py)
# ─────────────────────────────────────────────────────────────────────────────

def configure_logging(level: str = "INFO") -> logging.Logger:
    """Configure root logger and return the application logger."""
    numeric = getattr(logging, level, logging.INFO)

    fmt = (
        "%(asctime)s | %(levelname)-8s | %(name)-25s | %(message)s"
    )
    date_fmt = "%Y-%m-%d %H:%M:%S"

    logging.basicConfig(
        level=numeric,
        format=fmt,
        datefmt=date_fmt,
        handlers=[
            logging.StreamHandler(),
        ],
    )

    # Silence noisy third-party loggers
    logging.getLogger("telethon").setLevel(logging.WARNING)

    return logging.getLogger("telegram_monitor")