defmodule Concord.Performance.EmbeddedScenariosBenchmark do
  @moduledoc """
  Realistic performance benchmarks for Concord as an embedded database.

  These benchmarks simulate common usage patterns in Elixir applications
  that would embed Concord as a dependency.
  """

  def run_embedded_benchmarks do
    IO.puts("🏗️  Concord Embedded Scenarios Benchmark")
    IO.puts("====================================")
    IO.puts("Testing realistic embedded application usage...")
    IO.puts("")

    setup_concord()

    # Run realistic embedded scenarios
    web_application_scenario()
    phoenix_session_store_scenario()
    configuration_management_scenario()
    feature_flag_scenario()
    caching_scenario()
    distributed_lock_scenario()
    pubsub_state_scenario()

    IO.puts("\n✅ All embedded scenario benchmarks completed!")
  end

  defp setup_concord do
    Application.ensure_all_started(:concord)
    :timer.sleep(1000)
    :ets.delete_all_objects(:concord_store)
    IO.puts("✅ Concord ready for embedded scenario testing")
  end

  def web_application_scenario do
    IO.puts("\n🌐 Web Application Scenario")
    IO.puts("==========================")

    # Simulate a web application storing user sessions, request counts, etc.
    IO.puts("Simulating web application with user sessions and analytics...")

    benchee_run(
      %{
        "store_user_session" => fn ->
          user_id = System.unique_integer()

          session_data = %{
            user_id: user_id,
            session_id: "sess_#{user_id}",
            csrf_token: Base.encode64(:crypto.strong_rand_bytes(32)),
            last_activity: DateTime.utc_now(),
            ip_address: "192.168.1.#{rem(user_id, 255)}"
          }

          # 30 min TTL
          Concord.put("session:#{user_id}", session_data, ttl: 1800)
        end,
        "track_page_view" => fn ->
          user_id = :rand.uniform(1000)
          page = "/page#{:rand.uniform(100)}"

          Concord.put(
            "analytics:#{user_id}:pages:#{System.unique_integer()}",
            %{
              page: page,
              timestamp: DateTime.utc_now(),
              user_agent: "Mozilla/5.0..."
            },
            # 24 hour TTL
            ttl: 86400
          )
        end,
        "rate_limit_check" => fn ->
          user_id = :rand.uniform(1000)
          key = "rate_limit:#{user_id}:#{DateTime.utc_now() |> DateTime.to_date()}"

          # Get current count
          current =
            case Concord.get(key) do
              {:ok, count} -> count
              {:error, :not_found} -> 0
            end

          # Increment and check against limit
          new_count = current + 1
          Concord.put(key, new_count, ttl: 86400)
          # Assuming 100 requests per day limit
          new_count <= 100
        end,
        "cache_api_response" => fn ->
          endpoint = "/api/v1/resource#{:rand.uniform(50)}"

          response = %{
            data: "api_response_data_#{System.unique_integer()}",
            cached_at: DateTime.utc_now(),
            expires_in: 300
          }

          # 5 min cache
          Concord.put("cache:api:#{endpoint}", response, ttl: 300)
        end
      },
      "Web Application Operations"
    )
  end

  def phoenix_session_store_scenario do
    IO.puts("\n🔥 Phoenix Session Store Scenario")
    IO.puts("=================================")

    # Simulate Phoenix using Concord as session store
    IO.puts("Simulating Phoenix session storage patterns...")

    benchee_run(
      %{
        "create_session" => fn ->
          session_id = Base.encode64(:crypto.strong_rand_bytes(24))

          session_data = %{
            user_id: System.unique_integer([:positive]),
            flash: %{"info" => "Welcome!"},
            locale: "en",
            timezone: "UTC"
          }

          # 2 hours
          Concord.put("phx_sess:#{session_id}", session_data, ttl: 7200)
        end,
        "load_session" => fn ->
          session_id = Base.encode64(:crypto.strong_rand_bytes(24))
          # Pre-create session
          Concord.put("phx_sess:#{session_id}", %{user_id: 123}, ttl: 7200)
          # Load it
          Concord.get("phx_sess:#{session_id}")
        end,
        "update_session" => fn ->
          session_id = Base.encode64(:crypto.strong_rand_bytes(24))
          Concord.put("phx_sess:#{session_id}", %{user_id: 123}, ttl: 7200)

          # Update with new data
          updated_data = %{
            user_id: 123,
            flash: %{"success" => "Profile updated"},
            last_activity: DateTime.utc_now()
          }

          Concord.put("phx_sess:#{session_id}", updated_data, ttl: 7200)
        end,
        "cleanup_expired_sessions" => fn ->
          # Simulate cleanup by touching valid sessions
          session_id = Base.encode64(:crypto.strong_rand_bytes(24))
          Concord.put("phx_sess:#{session_id}", %{user_id: 123}, ttl: 7200)
          Concord.touch("phx_sess:#{session_id}", 7200)
        end
      },
      "Phoenix Session Store Operations"
    )
  end

  def configuration_management_scenario do
    IO.puts("\n⚙️  Configuration Management Scenario")
    IO.puts("=====================================")

    # Simulate dynamic configuration management
    IO.puts("Simulating dynamic configuration updates...")

    # Pre-populate some configuration
    config_data = %{
      database: %{host: "localhost", port: 5432, pool_size: 10},
      features: %{new_ui: true, beta_features: false},
      limits: %{max_requests_per_minute: 1000, max_upload_size: 10_485_760}
    }

    Concord.put("config:app", config_data)

    benchee_run(
      %{
        "get_config_value" => fn ->
          case Concord.get("config:app") do
            {:ok, config} -> config[:database][:port]
            {:error, _} -> 5432
          end
        end,
        "update_feature_flag" => fn ->
          case Concord.get("config:app") do
            {:ok, config} ->
              updated_config = put_in(config, [:features, :beta_features], true)
              Concord.put("config:app", updated_config)

            {:error, _} ->
              :ok
          end
        end,
        "get_nested_config" => fn ->
          case Concord.get("config:app") do
            {:ok, config} ->
              {
                config[:database][:pool_size],
                config[:limits][:max_requests_per_minute],
                config[:features][:new_ui]
              }

            {:error, _} ->
              {10, 1000, false}
          end
        end,
        "cache_configuration" => fn ->
          # Simulate caching configuration in process dictionary
          case Concord.get("config:app") do
            {:ok, config} ->
              Process.put(:cached_config, config)
              config

            {:error, _} ->
              %{}
          end
        end
      },
      "Configuration Management Operations"
    )
  end

  def feature_flag_scenario do
    IO.puts("\n🚩 Feature Flag Scenario")
    IO.puts("=========================")

    # Simulate feature flag management system
    IO.puts("Simulating feature flag operations...")

    # Pre-populate feature flags
    feature_flags = %{
      "new_dashboard" => %{
        enabled: true,
        rollout_percentage: 100,
        user_ids: [],
        conditions: %{plan: ["premium", "enterprise"]}
      },
      "beta_search" => %{
        enabled: false,
        rollout_percentage: 20,
        user_ids: [123, 456, 789],
        conditions: %{beta: true}
      }
    }

    for {flag, data} <- feature_flags do
      Concord.put("flag:#{flag}", data)
    end

    benchee_run(
      %{
        "check_feature_flag" => fn ->
          flag = "new_dashboard"
          user_id = System.unique_integer([:positive])
          user_plan = if rem(user_id, 3) == 0, do: "premium", else: "basic"

          case Concord.get("flag:#{flag}") do
            {:ok, flag_data} ->
              enabled =
                flag_data.enabled and
                  (flag_data.rollout_percentage >= 50 or
                     user_id in flag_data.user_ids or
                     user_plan in flag_data.conditions.plan)

              enabled

            {:error, _} ->
              false
          end
        end,
        "enable_feature_for_user" => fn ->
          flag = "beta_search"
          user_id = System.unique_integer([:positive])

          case Concord.get("flag:#{flag}") do
            {:ok, flag_data} ->
              updated_users = [user_id | flag_data.user_ids] |> Enum.uniq()
              updated_flag = %{flag_data | user_ids: updated_users, enabled: true}
              Concord.put("flag:#{flag}", updated_flag)

            {:error, _} ->
              :ok
          end
        end,
        "bulk_flag_check" => fn ->
          flags = ["new_dashboard", "beta_search", "advanced_analytics", "real_time_sync"]
          user_id = System.unique_integer([:positive])

          for flag <- flags do
            case Concord.get("flag:#{flag}") do
              {:ok, flag_data} -> flag_data.enabled
              {:error, _} -> false
            end
          end
        end
      },
      "Feature Flag Operations"
    )
  end

  def caching_scenario do
    IO.puts("\n💾 Caching Scenario")
    IO.puts("===================")

    # Simulate application-level caching
    IO.puts("Simulating caching layer operations...")

    benchee_run(
      %{
        "cache_computation_result" => fn ->
          cache_key = "calc:result:#{:rand.uniform(100)}"

          result = %{
            value: :rand.uniform(1000),
            computed_at: DateTime.utc_now(),
            computation_time_ms: :rand.uniform(100)
          }

          # 5 minute cache
          Concord.put(cache_key, result, ttl: 300)
        end,
        "get_cached_result" => fn ->
          cache_key = "calc:result:#{:rand.uniform(100)}"

          case Concord.get(cache_key) do
            {:ok, cached} ->
              cached[:value]

            {:error, :not_found} ->
              # Simulate computation and cache result
              result = :rand.uniform(1000)
              Concord.put(cache_key, %{value: result, computed_at: DateTime.utc_now()}, ttl: 300)
              result
          end
        end,
        "cache_invalidation" => fn ->
          pattern = "calc:result:*"
          # In real implementation, this would be more sophisticated
          # For now, simulate by touching with short TTL
          for i <- 1..10 do
            Concord.touch("calc:result:#{i}", 1)
          end
        end,
        "bulk_cache_operations" => fn ->
          operations =
            for i <- 1..50 do
              %{"key" => "bulk:cache:#{i}", "value" => "cached_value_#{i}", "ttl" => 600}
            end

          Concord.put_many(operations)
        end
      },
      "Caching Operations"
    )
  end

  def distributed_lock_scenario do
    IO.puts("\n🔒 Distributed Lock Scenario")
    IO.puts("=============================")

    # Simulate distributed locking using Concord
    IO.puts("Simulating distributed lock operations...")

    benchee_run(
      %{
        "acquire_lock" => fn ->
          lock_key = "lock:resource:#{System.unique_integer()}"

          lock_data = %{
            owner: self(),
            acquired_at: DateTime.utc_now(),
            expires_at: DateTime.add(DateTime.utc_now(), 30, :second)
          }

          Concord.put(lock_key, lock_data, ttl: 30)
        end,
        "check_lock_status" => fn ->
          lock_key = "lock:resource:#{System.unique_integer()}"

          case Concord.get(lock_key) do
            {:ok, lock_data} ->
              expired = DateTime.compare(lock_data.expires_at, DateTime.utc_now()) == :lt
              not expired and lock_data.owner == self()

            # Lock available
            {:error, :not_found} ->
              true
          end
        end,
        "release_lock" => fn ->
          lock_key = "lock:resource:#{System.unique_integer()}"
          # Simulate lock acquisition
          Concord.put(lock_key, %{owner: self()}, ttl: 30)
          # Release it
          Concord.delete(lock_key)
        end,
        "lock_renewal" => fn ->
          lock_key = "lock:resource:#{System.unique_integer()}"
          # Acquire lock
          Concord.put(lock_key, %{owner: self()}, ttl: 30)
          # Renew it
          Concord.touch(lock_key, 60)
        end
      },
      "Distributed Lock Operations"
    )
  end

  def pubsub_state_scenario do
    IO.puts("\n📡 PubSub State Scenario")
    IO.puts("==========================")

    # Simulate PubSub state management
    IO.puts("Simulating PubSub state synchronization...")

    benchee_run(
      %{
        "store_subscriber_state" => fn ->
          topic = "events:user:#{System.unique_integer([:positive])}"
          subscriber = self()

          state = %{
            last_seen: System.unique_integer(),
            subscriber: subscriber,
            subscribed_at: DateTime.utc_now()
          }

          Concord.put("pubsub:#{topic}:#{subscriber}", state, ttl: 3600)
        end,
        "broadcast_to_subscribers" => fn ->
          topic = "events:global"
          message_id = System.unique_integer()
          message = %{id: message_id, type: "notification", data: "Hello World"}

          # Store message for subscribers
          Concord.put("pubsub:#{topic}:msg:#{message_id}", message, ttl: 300)

          # Update topic state
          case Concord.get("pubsub:#{topic}:state") do
            {:ok, state} ->
              updated_state = %{
                state
                | last_message_id: message_id,
                  message_count: state.message_count + 1
              }

              Concord.put("pubsub:#{topic}:state", updated_state)

            {:error, :not_found} ->
              initial_state = %{last_message_id: message_id, message_count: 1}
              Concord.put("pubsub:#{topic}:state", initial_state)
          end
        end,
        "get_subscriber_state" => fn ->
          topic = "events:user:#{System.unique_integer([:positive])}"
          subscriber = self()

          case Concord.get("pubsub:#{topic}:#{subscriber}") do
            {:ok, state} -> state.last_seen
            {:error, :not_found} -> 0
          end
        end,
        "cleanup_expired_states" => fn ->
          # Simulate cleanup of expired subscriber states
          for i <- 1..20 do
            Concord.touch("pubsub:cleanup:test:#{i}", 1)
          end
        end
      },
      "PubSub State Operations"
    )
  end

  defp benchee_run(jobs, description) do
    IO.puts("\n#{description}:")

    try do
      if Code.ensure_loaded?(Benchee) do
        Benchee.run(%{
          time: 3,
          memory_time: 1,
          print: [configuration: false],
          inputs: %{
            "Embedded Scenario" => jobs
          }
        })
      else
        simple_benchmark(jobs)
      end
    rescue
      _ -> simple_benchmark(jobs)
    end
  end

  defp simple_benchmark(jobs) do
    for {name, fun} <- jobs do
      # Warm up
      fun.()

      # Measure
      measurements =
        for _i <- 1..100 do
          {time_us, _result} = :timer.tc(fun)
          time_us
        end

      avg_time = Enum.sum(measurements) / length(measurements)
      min_time = Enum.min(measurements)
      max_time = Enum.max(measurements)
      ops_per_sec = Float.round(1_000_000 / avg_time, 2)

      IO.puts("  #{name}:")
      IO.puts("    Average: #{Float.round(avg_time, 2)}μs (#{ops_per_sec} ops/sec)")
      IO.puts("    Range: #{min_time}μs - #{max_time}μs")
    end
  end
end