"""
api_key_loader.py — API key management for Groq and HuggingFace Inference API.

IMPROVEMENTS (v2):
  - ADDED:   Persistent state tracking (last_used_key_index, call_counts)
  - ADDED:   Intelligent key rotation with failure awareness
  - ADDED:   Health tracking for each API key
  - ADDED:   State persistence via JSON state file
  - KEPT:    Groq key rotation (enhanced round-robin)
  - REMOVED: Together AI (unreliable, rate-limited)
  - REMOVED: Gemini stub (kept for backward compat only)

Supported env vars:
  GROQ_API_KEY       — single Groq key
  GROQ_API_KEYS      — comma-separated Groq keys (rotated with tracking)
  HF_TOKEN           — HuggingFace token (optional, increases rate limits)

State file: .api_state.json — tracks key usage, failure counts, rotations
"""

import os
import json
import logging
from typing import List, Optional, Dict, Any
from pathlib import Path
from dotenv import load_dotenv

load_dotenv()
logger = logging.getLogger(__name__)


class APIKeyManager:
    """
    Manages API keys for Groq and HuggingFace with intelligent load balancing.
    
    Features:
    - Round-robin rotation with persistent state tracking
    - Failure counting per key (skips consistently failing keys)
    - Call count tracking per key
    - Dynamic allocation based on key health
    """

    STATE_FILE = ".api_state.json"
    MAX_KEY_FAILURES = 5  # Skip key after N consecutive failures

    def __init__(self):
        self.groq_keys: List[str] = []
        self.groq_index: int = 0
        self.hf_token: Optional[str] = None

        # State tracking for load balancing
        self.state: Dict[str, Any] = {
            "last_used_groq_index": 0,
            "groq_call_counts": {},      # key_index -> call_count
            "groq_failure_counts": {},   # key_index -> consecutive_failure_count
            "groq_total_calls": 0,
            "groq_total_failures": 0,
        }

        # Legacy stubs — kept for backward compat but unused
        self.together_keys: List[str] = []
        self.together_index: int = 0
        self.gemini_keys: List[str] = []
        self.gemini_index: int = 0

        self._load_keys()
        self._load_state()

    def _load_keys(self):
        """Load API keys from environment."""
        # --- Groq ---
        groq_keys_str = os.getenv("GROQ_API_KEYS", "").strip()
        if groq_keys_str:
            self.groq_keys = [k.strip() for k in groq_keys_str.split(",") if k.strip()]
        if not self.groq_keys:
            single = os.getenv("GROQ_API_KEY", "").strip()
            if single:
                self.groq_keys = [single]

        # Initialize state for each key
        for i in range(len(self.groq_keys)):
            self.state["groq_call_counts"].setdefault(str(i), 0)
            self.state["groq_failure_counts"].setdefault(str(i), 0)

        # --- HuggingFace ---
        self.hf_token = os.getenv("HF_TOKEN", "").strip() or None

        # --- Legacy Together AI & Gemini (stubs only) ---
        together_keys_str = os.getenv("TOGETHER_API_KEYS", "").strip()
        if together_keys_str:
            self.together_keys = [k.strip() for k in together_keys_str.split(",") if k.strip()]
        if not self.together_keys:
            single = os.getenv("TOGETHER_API_KEY", "").strip()
            if single:
                self.together_keys = [single]

        gemini_keys_str = os.getenv("GEMINI_API_KEYS", "").strip()
        if gemini_keys_str:
            self.gemini_keys = [k.strip() for k in gemini_keys_str.split(",") if k.strip()]
        if not self.gemini_keys:
            single = os.getenv("GEMINI_API_KEY", "").strip()
            if single:
                self.gemini_keys = [single]

    def _load_state(self):
        """Load persisted state from disk."""
        state_path = Path(self.STATE_FILE)
        if state_path.exists():
            try:
                with open(state_path, "r", encoding="utf-8") as f:
                    saved_state = json.load(f)
                self.state.update(saved_state)
                self.groq_index = self.state.get("last_used_groq_index", 0)
                logger.info(f"✓ Loaded API state: Groq index={self.groq_index}, "
                           f"calls={self.state['groq_total_calls']}, "
                           f"failures={self.state['groq_total_failures']}")
            except Exception as e:
                logger.warning(f"Failed to load API state: {e}. Starting fresh.")

    def _save_state(self):
        """Persist state to disk."""
        self.state["last_used_groq_index"] = self.groq_index
        state_path = Path(self.STATE_FILE)
        try:
            with open(state_path, "w", encoding="utf-8") as f:
                json.dump(self.state, f, indent=2)
        except Exception as e:
            logger.warning(f"Failed to save API state: {e}")

    def _is_key_healthy(self, key_index: int) -> bool:
        """Check if a key is healthy (not exceeding failure threshold)."""
        failures = self.state["groq_failure_counts"].get(str(key_index), 0)
        is_healthy = failures < self.MAX_KEY_FAILURES
        if not is_healthy:
            logger.warning(f"⚠ Groq key {key_index} has {failures} failures — skipping")
        return is_healthy

    def _get_next_healthy_key_index(self, start_index: int) -> int:
        """Find the next healthy key starting from start_index."""
        for attempt in range(len(self.groq_keys)):
            candidate = (start_index + attempt) % len(self.groq_keys)
            if self._is_key_healthy(candidate):
                return candidate
        # All keys failing — reset failure counts and use start_index
        logger.warning("⚠ All Groq keys unhealthy. Resetting failure counts...")
        for i in range(len(self.groq_keys)):
            self.state["groq_failure_counts"][str(i)] = 0
        return start_index

    # ================================================================ Groq
    def get_groq_key(self, skip_index: Optional[int] = None) -> Optional[str]:
        """
        Get next Groq API key with intelligent load balancing.
        
        Args:
            skip_index: If provided, skip this specific key index and return next healthy key
            
        Returns:
            API key string, or None if no keys available
        """
        if not self.groq_keys:
            return None

        if skip_index is not None:
            # Skip the provided index and find next healthy key
            self.groq_index = self._get_next_healthy_key_index(skip_index + 1)
            logger.info(f"⟲ Skipped Groq key {skip_index}, using key {self.groq_index}")
        else:
            # Normal round-robin to next healthy key
            self.groq_index = self._get_next_healthy_key_index(self.groq_index)

        key = self.groq_keys[self.groq_index]
        
        # Advance index for next call
        next_index = (self.groq_index + 1) % len(self.groq_keys)
        self.groq_index = self._get_next_healthy_key_index(next_index)

        return key

    def track_groq_call(self, key: str, success: bool = True):
        """
        Track an actual Groq API call (not just key retrieval).
        Call this AFTER making an actual API request.
        
        Args:
            key: The API key that was used
            success: Whether the call succeeded
        """
        try:
            key_index = self.groq_keys.index(key)
            key_idx_str = str(key_index)
            
            self.state["groq_call_counts"][key_idx_str] = self.state["groq_call_counts"].get(key_idx_str, 0) + 1
            self.state["groq_total_calls"] += 1
            
            if success:
                # Reset failures on success
                self.state["groq_failure_counts"][key_idx_str] = 0
            else:
                # Increment failures
                self.state["groq_failure_counts"][key_idx_str] = self.state["groq_failure_counts"].get(key_idx_str, 0) + 1
                self.state["groq_total_failures"] += 1
            
            self._save_state()
        except ValueError:
            logger.warning("Call tracked for unknown Groq key")

    def mark_groq_key_failure(self, key: str):
        """Record a failure for a Groq key (DEPRECATED — use track_groq_call instead)."""
        self.track_groq_call(key, success=False)

    def mark_groq_key_success(self, key: str):
        """Clear failures for a Groq key after successful use (DEPRECATED — use track_groq_call instead)."""
        self.track_groq_call(key, success=True)

    def get_groq_key_count(self) -> int:
        """Return total number of Groq keys."""
        return len(self.groq_keys)

    def get_groq_stats(self) -> Dict[str, Any]:
        """Get detailed statistics about Groq key usage."""
        stats = {
            "total_keys": len(self.groq_keys),
            "total_calls": self.state["groq_total_calls"],
            "total_failures": self.state["groq_total_failures"],
            "current_index": self.groq_index,
            "per_key": {}
        }
        for i in range(len(self.groq_keys)):
            idx_str = str(i)
            stats["per_key"][i] = {
                "calls": self.state["groq_call_counts"].get(idx_str, 0),
                "failures": self.state["groq_failure_counts"].get(idx_str, 0),
                "healthy": self._is_key_healthy(i),
            }
        return stats

    def is_groq_available(self) -> bool:
        """Check if any Groq keys are available."""
        return len(self.groq_keys) > 0

    # ================================================== HuggingFace
    def get_hf_token(self) -> Optional[str]:
        """Get HuggingFace token."""
        return self.hf_token

    def is_hf_available(self) -> bool:
        """HF Inference API works without a token (rate-limited)."""
        return True

    # ================================================== Legacy stubs
    def get_together_key(self, skip_index: Optional[int] = None) -> Optional[str]:
        """Stub — Together AI removed. Returns None."""
        return None

    def get_together_key_count(self) -> int:
        return 0

    def is_together_available(self) -> bool:
        return False

    def get_gemini_key(self, skip_index: Optional[int] = None) -> Optional[str]:
        """Stub — Gemini removed. Returns None."""
        return None

    def get_gemini_key_count(self) -> int:
        return 0

    def is_gemini_available(self) -> bool:
        return False


# Global singleton
_api_manager = APIKeyManager()


def get_api_manager() -> APIKeyManager:
    return _api_manager


# Convenience wrappers
def get_next_groq_key(skip_index: Optional[int] = None) -> Optional[str]:
    return get_api_manager().get_groq_key(skip_index)


def get_hf_token() -> Optional[str]:
    return get_api_manager().get_hf_token()


# Legacy stubs (kept so old imports don't break)
def get_next_together_key(skip_index: Optional[int] = None) -> Optional[str]:
    return None


def get_next_gemini_key(skip_index: Optional[int] = None) -> Optional[str]:
    return None