raxol

defmodule Raxol.Cloud.EdgeComputing do
  @moduledoc """
  Edge computing support for Raxol applications.

  This module provides functionality for optimizing Raxol applications
  at the edge, allowing for improved performance, reduced latency,
  and offline capabilities.

  Features:
  * Edge processing configuration
  * Offline mode and data synchronization
  * Resource optimization for edge devices
  * Automatic failover between edge and cloud
  * Edge-specific monitoring and diagnostics
  * Edge-to-cloud data streaming
  """

  alias Raxol.Cloud.EdgeComputing.{Core, Execution, Connection}

  @doc """
  Initializes the edge computing system.

  ## Options

  * `:mode` - Operation mode (:edge_only, :cloud_only, :hybrid) (default: :hybrid)
  * `:connection_check_interval` - Time in ms between connection checks (default: 5000)
  * `:sync_interval` - Time in ms between cloud syncs (default: 30000)
  * `:retry_limit` - Number of retry attempts for operations (default: 5)
  * `:compression_enabled` - Whether to compress data for transfer (default: true)
  * `:offline_cache_size` - Maximum size in bytes for offline cache (default: 100MB)
  * `:priority_functions` - List of functions that should prioritize edge execution

  ## Examples

      iex> init(mode: :hybrid)
      :ok
  """
  defdelegate init(opts \\ []), to: Core

  @doc """
  Updates the edge computing configuration.
  """
  defdelegate update_config(state \\ nil, config), to: Core

  @doc """
  Executes a function at the edge or in the cloud based on current mode and conditions.

  ## Options

  * `:force_edge` - Force execution at the edge even in hybrid mode (default: false)
  * `:force_cloud` - Force execution in the cloud even in hybrid mode (default: false)
  * `:fallback_fn` - Function to execute if primary execution fails (default: nil)
  * `:timeout` - Timeout in milliseconds for the operation (default: 5000)
  * `:retry` - Number of retry attempts (default: from config)

  ## Examples

      iex> execute(fn -> process_data(data) end)
      {:ok, result}
  """
  defdelegate execute(func, opts \\ []), to: Execution

  @doc """
  Synchronizes data between edge and cloud.

  ## Options

  * `:force` - Force immediate synchronization (default: false)
  * `:selective` - List of data types to synchronize (default: all)
  * `:direction` - Sync direction (:both, :to_cloud, :from_cloud) (default: :both)
  * `:conflict_resolution` - Strategy for resolving conflicts (default: :latest_wins)

  ## Examples

      iex> sync(force: true)
      {:ok, %{status: :completed, synced_items: 5}}
  """
  def sync(_opts \\ []) do
    # Sync with cloud
    :ok
  end

  @doc """
  Checks if the system is currently operating in offline mode.
  """
  defdelegate offline?, to: Core

  @doc """
  Gets the current status of the edge computing system.
  """
  defdelegate status, to: Core

  @doc """
  Manually checks the cloud connection status and updates the system state.
  """
  defdelegate check_connection, to: Connection

  @doc """
  Forces the system into a specific mode.
  """
  defdelegate force_mode(mode), to: Core

  @doc """
  Gets metrics for the edge computing system.
  """
  defdelegate get_metrics, to: Core

  @doc """
  Clears the edge cache.
  """
  defdelegate clear_cache, to: Core

  # All private functions have been moved to focused modules
end

# Cache implementation for edge computing
defmodule Raxol.Cloud.EdgeComputing.Cache do
  @moduledoc false

  # Process dictionary key for cache
  @cache_key :raxol_edge_cache

  def init(config) do
    cache = %{
      items: %{},
      size: 0,
      max_size: config.offline_cache_size
    }

    Process.put(@cache_key, cache)
    :ok
  end

  def put(key, value, opts \\ []) do
    cache = get_cache()

    # Calculate size of data (simplified)
    data_size = :erlang.term_to_binary(value) |> byte_size()

    # Check if we have space
    if cache.size + data_size > cache.max_size do
      # Need to evict something
      evict(data_size)
    end

    # Add the item
    item = %{
      value: value,
      size: data_size,
      created_at: DateTime.utc_now(),
      ttl: Keyword.get(opts, :ttl),
      metadata: Keyword.get(opts, :metadata, %{})
    }

    updated_items = Map.put(cache.items, key, item)
    updated_size = cache.size + data_size

    # Update cache
    Process.put(@cache_key, %{cache | items: updated_items, size: updated_size})

    :ok
  end

  def get(key) do
    cache = get_cache()

    case Map.get(cache.items, key) do
      nil ->
        nil

      item ->
        # Check TTL
        if item.ttl &&
             DateTime.diff(DateTime.utc_now(), item.created_at) > item.ttl do
          # Item expired
          delete(key)
          nil
        else
          item.value
        end
    end
  end

  def delete(key) do
    cache = get_cache()

    case Map.get(cache.items, key) do
      nil ->
        :ok

      item ->
        # Update cache
        updated_items = Map.delete(cache.items, key)
        updated_size = cache.size - item.size

        Process.put(@cache_key, %{
          cache
          | items: updated_items,
            size: updated_size
        })

        :ok
    end
  end

  def clear do
    cache = get_cache()

    # Reset cache
    Process.put(@cache_key, %{cache | items: %{}, size: 0})

    :ok
  end

  def usage do
    cache = get_cache()

    %{
      item_count: map_size(cache.items),
      size: cache.size,
      max_size: cache.max_size,
      percentage_used: cache.size / cache.max_size * 100
    }
  end

  # Private helpers

  defp get_cache do
    Process.get(@cache_key) || %{items: %{}, size: 0, max_size: 100_000_000}
  end

  defp evict(needed_size) do
    cache = get_cache()

    if map_size(cache.items) == 0 do
      :ok
    else
      # Simple LRU eviction strategy
      # Sort by creation time (oldest first)
      sorted_items =
        cache.items
        |> Enum.sort_by(fn {_, item} -> item.created_at end, DateTime)

      # Start evicting until we have enough space
      {updated_items, updated_size} =
        evict_items(sorted_items, cache.items, cache.size, needed_size)

      # Update cache
      Process.put(@cache_key, %{
        cache
        | items: updated_items,
          size: updated_size
      })

      :ok
    end
  end

  defp evict_items([], items, size, _) do
    # Nothing left to evict
    {items, size}
  end

  defp evict_items([{key, item} | rest], items, size, needed_size) do
    # Remove this item
    updated_items = Map.delete(items, key)
    updated_size = size - item.size

    # Check if we have enough space now
    if size - updated_size >= needed_size do
      # We've freed enough space
      {updated_items, updated_size}
    else
      # Need to evict more
      evict_items(rest, updated_items, updated_size, needed_size)
    end
  end
end

# Queue implementation for edge computing
defmodule Raxol.Cloud.EdgeComputing.Queue do
  @moduledoc false

  # Process dictionary key for queue
  @queue_key :raxol_edge_queue

  def init(_config) do
    queue = %{
      operations: [],
      next_id: 1
    }

    Process.put(@queue_key, queue)
    :ok
  end

  def enqueue_operation(type, data) do
    queue = get_queue()

    operation = %{
      id: queue.next_id,
      type: type,
      data: data,
      created_at: DateTime.utc_now(),
      attempts: 0
    }

    # Add operation to queue
    updated_operations = queue.operations ++ [operation]

    # Update queue
    Process.put(@queue_key, %{
      queue
      | operations: updated_operations,
        next_id: queue.next_id + 1
    })

    operation.id
  end

  def pending_count do
    queue = get_queue()
    length(queue.operations)
  end

  @doc """
  Process all pending operations in the queue.
  """
  def process_pending do
    queue = get_queue()

    # Process each operation
    {processed, remaining} =
      Enum.split_with(queue.operations, fn operation ->
        result = process_operation(operation)
        result == :ok || result == :failed
      end)

    # Update queue with remaining operations
    Process.put(@queue_key, %{queue | operations: remaining})

    # Return number of processed operations
    length(processed)
  end

  # Private helpers

  defp get_queue do
    Process.get(@queue_key) || %{operations: [], next_id: 1}
  end

  defp process_operation(operation) do
    # Increment attempt counter
    operation = %{operation | attempts: operation.attempts + 1}

    # Process based on type
    case operation.type do
      :function ->
        # Execute the function in the cloud
        func = operation.data.function
        _opts = operation.data.options

        try do
          # Simulate cloud execution
          _result = func.()
          :ok
        rescue
          _ ->
            if operation.attempts >= 3 do
              :failed
            else
              :retry
            end
        end

      :sync ->
        Raxol.Cloud.EdgeComputing.SyncManager.sync(operation.data)

      _ ->
        :failed
    end
  end
end

# Sync manager implementation for edge computing
defmodule Raxol.Cloud.EdgeComputing.SyncManager do
  @moduledoc false

  # Process dictionary key for sync state
  @sync_key :raxol_edge_sync_state

  def init(config) do
    sync_state = %{
      last_sync: nil,
      config: config,
      pending_changes: %{},
      conflict_strategy: :latest_wins
    }

    Process.put(@sync_key, sync_state)
    :ok
  end

  def sync(_opts \\ []) do
    sync_state = get_sync_state()

    # Record the sync attempt
    updated_sync_state = %{sync_state | last_sync: DateTime.utc_now()}
    Process.put(@sync_key, updated_sync_state)

    # Simulate sync
    # In a real implementation, this would communicate with a cloud service
    Process.sleep(100)

    # Return success with some stats
    {:ok,
     %{
       status: :completed,
       synced_items: map_size(sync_state.pending_changes),
       timestamp: DateTime.utc_now()
     }}
  end

  # Private helpers

  defp get_sync_state do
    Process.get(@sync_key) ||
      %{
        last_sync: nil,
        config: %{},
        pending_changes: %{},
        conflict_strategy: :latest_wins
      }
  end
end