kimi gone wild

lib/odinsea/game/drop_table.ex

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+defmodule Odinsea.Game.DropTable do
+  @moduledoc """
+  Manages drop tables for monsters.
+  Ported from Java server.life.MonsterDropEntry and MapleMonsterInformationProvider
+
+  Drop tables define what items a monster can drop when killed.
+  Each drop entry includes:
+  - item_id: The item to drop
+  - chance: Drop rate (out of 1,000,000 for most items)
+  - min_quantity: Minimum quantity
+  - max_quantity: Maximum quantity
+  - quest_id: Quest requirement (-1 = no quest)
+  """
+
+  alias Odinsea.Game.LifeFactory
+
+  require Logger
+
+  @typedoc "A single drop entry"
+  @type drop_entry :: %{
+          item_id: integer(),
+          chance: integer(),
+          min_quantity: integer(),
+          max_quantity: integer(),
+          quest_id: integer()
+        }
+
+  @typedoc "Drop table for a monster"
+  @type drop_table :: [drop_entry()]
+
+  # Default drop rates for different item categories
+  @equip_drop_rate 0.05       # 5% base for equipment
+  @use_drop_rate 0.10         # 10% for use items
+  @etc_drop_rate 0.15         # 15% for etc items
+  @setup_drop_rate 0.02       # 2% for setup items
+  @cash_drop_rate 0.01        # 1% for cash items
+
+  # Meso drop configuration
+  @meso_chance_normal 400_000  # 40% base for normal mobs
+  @meso_chance_boss 1_000_000  # 100% for bosses
+
+  @doc """
+  Gets the drop table for a monster.
+  """
+  @spec get_drops(integer()) :: drop_table()
+  def get_drops(mob_id) do
+    # Try to get from cache first
+    case lookup_drop_table(mob_id) do
+      nil -> load_and_cache_drops(mob_id)
+      drops -> drops
+    end
+  end
+
+  @doc """
+  Calculates drops for a monster kill.
+  Returns a list of {item_id, quantity} tuples or {:meso, amount}.
+  """
+  @spec calculate_drops(integer(), integer(), map()) :: [{:item | :meso, integer(), integer()}]
+  def calculate_drops(mob_id, drop_rate_multiplier, _opts \\ %{}) do
+    drops = get_drops(mob_id)
+    
+    # Get monster stats for meso calculation
+    stats = LifeFactory.get_monster_stats(mob_id)
+    
+    results =
+      if stats do
+        # Check if meso drops are disabled for this monster type
+        should_drop_mesos = should_drop_mesos?(stats)
+        
+        # Add meso drops if applicable
+        meso_drops = 
+          if should_drop_mesos do
+            calculate_meso_drops(stats, drop_rate_multiplier)
+          else
+            []
+          end
+
+        # Roll for each item drop
+        item_drops = 
+          Enum.flat_map(drops, fn entry ->
+            case roll_drop(entry, drop_rate_multiplier) do
+              nil -> []
+              {item_id, quantity} -> [{:item, item_id, quantity}]
+            end
+          end)
+
+        meso_drops ++ item_drops
+      else
+        []
+      end
+
+    # Limit total drops to prevent flooding
+    Enum.take(results, 10)
+  end
+
+  @doc """
+  Rolls for a single drop entry.
+  Returns {item_id, quantity} if successful, nil if failed.
+  """
+  @spec roll_drop(drop_entry(), integer() | float()) :: {integer(), integer()} | nil
+  def roll_drop(entry, multiplier) do
+    # Calculate adjusted chance
+    base_chance = entry.chance
+    adjusted_chance = trunc(base_chance * multiplier)
+    
+    # Roll (1,000,000 = 100%)
+    roll = :rand.uniform(1_000_000)
+    
+    if roll <= adjusted_chance do
+      # Determine quantity
+      quantity = 
+        if entry.max_quantity > entry.min_quantity do
+          entry.min_quantity + :rand.uniform(entry.max_quantity - entry.min_quantity + 1) - 1
+        else
+          entry.min_quantity
+        end
+      
+      {entry.item_id, max(1, quantity)}
+    else
+      nil
+    end
+  end
+
+  @doc """
+  Calculates meso drops for a monster.
+  """
+  @spec calculate_meso_drops(map(), integer() | float()) :: [{:meso, integer(), integer()}]
+  def calculate_meso_drops(stats, drop_rate_multiplier) do
+    # Determine number of meso drops based on monster type
+    num_drops = 
+      cond do
+        stats.boss and not stats.party_bonus -> 2
+        stats.party_bonus -> 1
+        true -> 1
+      end
+
+    # Calculate max meso amount
+    level = stats.level
+    
+    # Formula: level * (level / 10) = max
+    # Min = 0.66 * max
+    divided = if level < 100, do: max(level, 10) / 10.0, else: level / 10.0
+    
+    max_amount = 
+      if stats.boss and not stats.party_bonus do
+        level * level
+      else
+        trunc(level * :math.ceil(level / divided))
+      end
+
+    min_amount = trunc(0.66 * max_amount)
+
+    # Roll for each meso drop
+    base_chance = if stats.boss and not stats.party_bonus, do: @meso_chance_boss, else: @meso_chance_normal
+    adjusted_chance = trunc(base_chance * drop_rate_multiplier)
+
+    Enum.flat_map(1..num_drops, fn _ ->
+      roll = :rand.uniform(1_000_000)
+      
+      if roll <= adjusted_chance do
+        amount = min_amount + :rand.uniform(max(1, max_amount - min_amount + 1)) - 1
+        [{:meso, max(1, amount), 1}]
+      else
+        []
+      end
+    end)
+  end
+
+  @doc """
+  Gets global drops that apply to all monsters.
+  """
+  @spec get_global_drops() :: drop_table()
+  def get_global_drops do
+    # Global drops from database (would be loaded from drop_data_global table)
+    # For now, return empty list
+    []
+  end
+
+  @doc """
+  Clears the drop table cache.
+  """
+  def clear_cache do
+    :ets.delete_all_objects(:drop_table_cache)
+  end
+
+  # ============================================================================
+  # Private Functions
+  # ============================================================================
+
+  defp lookup_drop_table(mob_id) do
+    case :ets.lookup(:drop_table_cache, mob_id) do
+      [{^mob_id, drops}] -> drops
+      [] -> nil
+    end
+  end
+
+  defp load_and_cache_drops(mob_id) do
+    drops = load_drops_from_source(mob_id)
+    :ets.insert(:drop_table_cache, {mob_id, drops})
+    drops
+  end
+
+  defp load_drops_from_source(mob_id) do
+    # In a full implementation, this would:
+    # 1. Query drop_data_final_v2 table
+    # 2. Apply chance adjustments based on item type
+    # 3. Return processed drops
+    
+    # For now, return fallback drops based on monster level
+    generate_fallback_drops(mob_id)
+  end
+
+  defp generate_fallback_drops(mob_id) do
+    # Get monster stats to determine level-appropriate drops
+    case LifeFactory.get_monster_stats(mob_id) do
+      nil -> []
+      stats -> generate_level_drops(stats)
+    end
+  end
+
+  defp generate_level_drops(stats) do
+    level = stats.level
+    
+    # Generate appropriate drops based on monster level
+    cond do
+      level <= 10 ->
+        # Beginner drops
+        [
+          %{item_id: 2000000, chance: 50_000, min_quantity: 1, max_quantity: 3, quest_id: -1},  # Red Potion
+          %{item_id: 2000001, chance: 50_000, min_quantity: 1, max_quantity: 3, quest_id: -1},  # Orange Potion
+          %{item_id: 4000000, chance: 30_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Snail Shell
+          %{item_id: 4000001, chance: 30_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Blue Snail Shell
+        ]
+      
+      level <= 20 ->
+        # Low level drops
+        [
+          %{item_id: 2000002, chance: 50_000, min_quantity: 1, max_quantity: 3, quest_id: -1},  # White Potion
+          %{item_id: 2000003, chance: 50_000, min_quantity: 1, max_quantity: 3, quest_id: -1},  # Blue Potion
+          %{item_id: 4000002, chance: 30_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Red Snail Shell
+          %{item_id: 4000010, chance: 30_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Mushroom Spores
+        ]
+      
+      level <= 40 ->
+        # Mid level drops
+        [
+          %{item_id: 2000004, chance: 40_000, min_quantity: 1, max_quantity: 3, quest_id: -1},  # Elixir
+          %{item_id: 2000005, chance: 40_000, min_quantity: 1, max_quantity: 3, quest_id: -1},  # Power Elixir
+          %{item_id: 4000011, chance: 30_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Pig's Head
+          %{item_id: 4000012, chance: 30_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Pig's Ribbon
+        ]
+      
+      level <= 70 ->
+        # Higher level drops
+        [
+          %{item_id: 2000005, chance: 50_000, min_quantity: 1, max_quantity: 5, quest_id: -1},  # Power Elixir
+          %{item_id: 2040000, chance: 10_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Scroll for Helmet
+          %{item_id: 2040800, chance: 10_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Scroll for Gloves
+        ]
+      
+      true ->
+        # High level drops
+        [
+          %{item_id: 2000005, chance: 60_000, min_quantity: 1, max_quantity: 10, quest_id: -1},  # Power Elixir
+          %{item_id: 2044000, chance: 5_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Scroll for Two-Handed Sword
+          %{item_id: 2044100, chance: 5_000, min_quantity: 1, max_quantity: 1, quest_id: -1},  # Scroll for Two-Handed Axe
+        ]
+    end
+  end
+
+  defp should_drop_mesos?(stats) do
+    # Don't drop mesos if:
+    # - Monster has special properties (invincible, friendly, etc.)
+    # - Monster is a fixed damage mob
+    # - Monster is a special event mob
+    
+    cond do
+      stats.invincible -> false
+      stats.friendly -> false
+      stats.fixed_damage > 0 -> false
+      stats.remove_after > 0 -> false
+      true -> true
+    end
+  end
+
+  @doc """
+  Initializes the drop table cache ETS table.
+  Called during application startup.
+  """
+  def init_cache do
+    :ets.new(:drop_table_cache, [
+      :set,
+      :public,
+      :named_table,
+      read_concurrency: true,
+      write_concurrency: true
+    ])
+    
+    Logger.info("Drop table cache initialized")
+    :ok
+  end
+
+  # ============================================================================
+  # GenServer Implementation (for supervision)
+  # ============================================================================
+
+  use GenServer
+
+  @doc """
+  Starts the DropTable cache manager.
+  """
+  def start_link(_opts) do
+    GenServer.start_link(__MODULE__, [], name: __MODULE__)
+  end
+
+  @impl true
+  def init(_) do
+    init_cache()
+    {:ok, %{}}
+  end
+end