import json
from pathlib import Path
from typing import Any, Dict, Optional

from src.llm.models import CharacterStateUpdate

DATA_CHARS_DIR = Path("data/chars")


def ensure_chars_dir():
    """Ensures the character data directory exists."""
    DATA_CHARS_DIR.mkdir(parents=True, exist_ok=True)


def get_character_state(character_name: str) -> Dict[str, Any]:
    """
    Reads character state from a JSON file.
    If the character doesn't exist, returns a default state.
    """
    ensure_chars_dir()
    file_path = DATA_CHARS_DIR / f"{character_name}.json"

    if not file_path.exists():
        return {
            "character_name": character_name,
            "stats": {"hp": 0, "max_hp": 0, "ac": 0},
            "status_effects": [],
            "inventory": [],
        }

    with open(file_path, "r", encoding="utf-8") as f:
        return json.load(f)


def update_character_state(update: CharacterStateUpdate):
    """
    Updates character state based on a CharacterStateUpdate model.
    Reads the current state, applies changes, and writes it back.
    """
    ensure_chars_dir()

    state = get_character_state(update.character_name)

    # Update HP
    if update.hp_change is not None:
        current_hp = state.get("stats", {}).get("hp", 0)
        state["stats"]["hp"] = current_hp + update.hp_change

    # Update Status Effects
    status_effects = set(state.get("status_effects", []))
    for effect in update.status_effects_added:
        status_effects.add(effect)
    for effect in update.status_effects_removed:
        status_effects.discard(effect)
    state["status_effects"] = list(status_effects)

    # Update Inventory
    inventory = state.get("inventory", [])
    for change in update.inventory_changes:
        # Find if item already exists
        item_exists = False
        for item in inventory:
            if item["item"] == change.item:
                if change.action == "added":
                    item["quantity"] = item.get("quantity", 1) + change.quantity
                elif change.action == "removed":
                    item["quantity"] = max(0, item.get("quantity", 1) - change.quantity)
                item_exists = True
                break

        if not item_exists:
            if change.action == "added":
                inventory.append(
                    {
                        "item": change.item,
                        "quantity": change.quantity,
                        "weight": 0,  # Default weight if not provided
                    }
                )
            elif change.action == "removed":
                # Item not in inventory, do nothing or log
                pass

    state["inventory"] = inventory

    file_path = DATA_CHARS_DIR / f"{update.character_name}.json"
    with open(file_path, "w", encoding="utf-8") as f:
        json.dump(state, f, indent=4)

    return str(file_path)