defmodule ExMCP.Compliance.ElicitationComplianceTest do
  @moduledoc """
  Comprehensive test suite for MCP 2025-06-18 elicitation compliance.

  Tests the following features:
  - Elicitation capability negotiation
  - Server-to-client elicitation requests
  - Schema validation for elicitation requests
  - Three-action response model (accept/reject/cancel)
  - Security considerations and validation
  - Rate limiting and user consent
  """
  use ExUnit.Case, async: true

  defmodule TestClientHandler do
    @behaviour ExMCP.Client.Handler

    @impl true
    def init(args), do: {:ok, args}

    @impl true
    def handle_ping(state), do: {:ok, %{}, state}

    @impl true
    def handle_list_roots(state) do
      {:ok, [%{uri: "file:///test", name: "test"}], state}
    end

    @impl true
    def handle_create_message(_params, state) do
      {:error, "Create message not supported in test", state}
    end

    @impl true
    def handle_elicitation_create(message, requested_schema, state) do
      # Simulate different user responses based on the message content
      case message do
        "Please provide your name" ->
          # Simulate user accepting and providing data
          {:ok, %{action: "accept", content: %{"name" => "Test User"}}, state}

        "Please provide sensitive data" ->
          # Simulate user rejecting
          {:ok, %{action: "reject"}, state}

        "Please provide optional info" ->
          # Simulate user canceling
          {:ok, %{action: "cancel"}, state}

        "Invalid schema test" ->
          # Simulate providing invalid data for testing validation
          {:ok, %{action: "accept", content: %{"name" => 123}}, state}

        _ ->
          # Default to accept for other cases
          case requested_schema["properties"] do
            %{"email" => _} ->
              {:ok, %{action: "accept", content: %{"email" => "test@example.com"}}, state}

            %{"age" => _} ->
              {:ok, %{action: "accept", content: %{"age" => 25}}, state}

            _ ->
              {:ok, %{action: "accept", content: %{}}, state}
          end
      end
    end
  end

  defmodule TestServerHandler do
    @behaviour ExMCP.Server.Handler

    @impl true
    def init(args), do: {:ok, args}

    @impl true
    def handle_initialize(_params, state) do
      result = %{
        protocolVersion: "2025-06-18",
        serverInfo: %{name: "elicitation-test-server", version: "1.0.0"},
        capabilities: %{
          tools: %{},
          # Server supports making elicitation requests
          experimental: %{elicitation: true}
        }
      }

      {:ok, result, state}
    end

    @impl true
    def handle_list_tools(_cursor, state) do
      tools = [
        %{
          name: "user_info_tool",
          description: "Tool that requests user information via elicitation",
          inputSchema: %{
            type: "object",
            properties: %{
              info_type: %{type: "string", enum: ["name", "email", "age"]}
            },
            required: ["info_type"]
          }
        }
      ]

      {:ok, tools, nil, state}
    end

    @impl true
    def handle_call_tool("user_info_tool", %{"info_type" => info_type}, state) do
      # This tool uses elicitation to request user information
      {_message, _schema} =
        case info_type do
          "name" ->
            {"Please provide your name",
             %{
               "type" => "object",
               "properties" => %{
                 "name" => %{
                   "type" => "string",
                   "title" => "Full Name",
                   "description" => "Your full name"
                 }
               },
               "required" => ["name"]
             }}

          "email" ->
            {"Please provide your email",
             %{
               "type" => "object",
               "properties" => %{
                 "email" => %{
                   "type" => "string",
                   "format" => "email",
                   "title" => "Email Address",
                   "description" => "Your email address"
                 }
               },
               "required" => ["email"]
             }}

          "age" ->
            {"Please provide your age",
             %{
               "type" => "object",
               "properties" => %{
                 "age" => %{
                   "type" => "number",
                   "minimum" => 0,
                   "maximum" => 150,
                   "title" => "Age",
                   "description" => "Your age in years"
                 }
               },
               "required" => ["age"]
             }}
        end

      # In a real implementation, this would make an elicitation request to the client
      # For testing, we'll simulate the response
      case info_type do
        "name" ->
          {:ok,
           %{
             content: [%{type: "text", text: "User provided name: Test User"}],
             structuredOutput: %{user_name: "Test User"}
           }, state}

        "email" ->
          {:ok,
           %{
             content: [%{type: "text", text: "User provided email: test@example.com"}],
             structuredOutput: %{user_email: "test@example.com"}
           }, state}

        "age" ->
          {:ok,
           %{
             content: [%{type: "text", text: "User provided age: 25"}],
             structuredOutput: %{user_age: 25}
           }, state}
      end
    end

    # Stub implementations for required callbacks
    @impl true
    def handle_list_resources(_cursor, state), do: {:ok, [], nil, state}

    @impl true
    def handle_read_resource(_uri, state), do: {:error, "Not implemented", state}

    @impl true
    def handle_list_prompts(_cursor, state), do: {:ok, [], nil, state}

    @impl true
    def handle_get_prompt(_name, _args, state), do: {:error, "Not implemented", state}
  end

  describe "elicitation capability negotiation" do
    test "client declares elicitation capability for 2025-06-18" do
      # Test that clients can declare elicitation capability
      client_capabilities = %{
        elicitation: %{}
      }

      assert Map.has_key?(client_capabilities, :elicitation)
    end

    test "server can indicate elicitation support in capabilities" do
      server_capabilities = %{
        experimental: %{elicitation: true}
      }

      assert get_in(server_capabilities, [:experimental, :elicitation]) == true
    end
  end

  describe "elicitation request format" do
    test "elicitation request has required fields" do
      # Test elicitation request structure
      elicit_request = %{
        message: "Please provide your GitHub username",
        requestedSchema: %{
          type: "object",
          properties: %{
            username: %{type: "string", title: "Username", description: "Your GitHub username"}
          },
          required: ["username"]
        }
      }

      assert is_binary(elicit_request.message)
      assert Map.has_key?(elicit_request, :requestedSchema)
      assert elicit_request.requestedSchema.type == "object"
      assert Map.has_key?(elicit_request.requestedSchema, :properties)
    end

    test "elicitation schema supports primitive types" do
      # Test all supported primitive types in elicitation schemas
      schema = %{
        type: "object",
        properties: %{
          # String type
          name: %{
            type: "string",
            title: "Name",
            description: "Your name",
            minLength: 1,
            maxLength: 100,
            pattern: "^[A-Za-z ]+$"
          },
          # Number type
          age: %{
            type: "number",
            title: "Age",
            description: "Your age",
            minimum: 0,
            maximum: 150
          },
          # Integer type
          count: %{
            type: "integer",
            title: "Count",
            minimum: 0
          },
          # Boolean type
          subscribe: %{
            type: "boolean",
            title: "Subscribe",
            description: "Subscribe to newsletter",
            default: false
          },
          # Enum type
          country: %{
            type: "string",
            title: "Country",
            enum: ["US", "CA", "UK"],
            enumNames: ["United States", "Canada", "United Kingdom"]
          },
          # Format examples
          email: %{type: "string", format: "email"},
          website: %{type: "string", format: "uri"},
          birthday: %{type: "string", format: "date"},
          created: %{type: "string", format: "date-time"}
        },
        required: ["name", "age"]
      }

      # Validate schema structure
      assert schema.type == "object"
      assert Map.has_key?(schema, :properties)
      assert Map.has_key?(schema, :required)

      # Check each property type
      properties = schema.properties

      get_property = fn key ->
        Map.get(properties, key) || Map.get(properties, String.to_atom(key))
      end

      assert get_property.("name").type == "string"
      assert get_property.("age").type == "number"
      assert get_property.("count").type == "integer"
      assert get_property.("subscribe").type == "boolean"
      assert get_property.("country").enum == ["US", "CA", "UK"]
      assert get_property.("email").format == "email"
    end

    test "elicitation schema validation constraints" do
      # Ensure schema follows elicitation restrictions
      valid_schema = %{
        type: "object",
        properties: %{
          simple_field: %{type: "string"}
        }
      }

      # Should be flat object with primitive properties only
      assert valid_schema.type == "object"
      assert is_map(valid_schema.properties)

      # Each property should be a primitive type
      Enum.each(valid_schema.properties, fn {_key, prop} ->
        assert prop.type in ["string", "number", "integer", "boolean"]
      end)
    end
  end

  describe "elicitation response actions" do
    test "accept action includes content" do
      response = %{
        action: "accept",
        content: %{
          name: "John Doe",
          email: "john@example.com"
        }
      }

      assert response.action == "accept"
      assert Map.has_key?(response, :content)
      assert is_map(response.content)
    end

    test "reject action omits content" do
      response = %{action: "reject"}

      assert response.action == "reject"
      refute Map.has_key?(response, :content)
    end

    test "cancel action omits content" do
      response = %{action: "cancel"}

      assert response.action == "cancel"
      refute Map.has_key?(response, :content)
    end

    test "all three actions are supported" do
      valid_actions = ["accept", "reject", "cancel"]

      Enum.each(valid_actions, fn action ->
        response = %{action: action}
        assert response.action in valid_actions
      end)
    end
  end

  describe "elicitation client handler integration" do
    test "client handler receives elicitation request" do
      # Test the client handler callback
      handler = TestClientHandler
      state = %{}

      message = "Please provide your name"

      requested_schema = %{
        "type" => "object",
        "properties" => %{
          "name" => %{"type" => "string", "title" => "Name"}
        },
        "required" => ["name"]
      }

      {:ok, result, ^state} = handler.handle_elicitation_create(message, requested_schema, state)

      assert result.action == "accept"
      assert result.content["name"] == "Test User"
    end

    test "client handler can reject elicitation" do
      handler = TestClientHandler
      state = %{}

      message = "Please provide sensitive data"

      requested_schema = %{
        "type" => "object",
        "properties" => %{
          "secret" => %{"type" => "string"}
        }
      }

      {:ok, result, ^state} = handler.handle_elicitation_create(message, requested_schema, state)

      assert result.action == "reject"
      refute Map.has_key?(result, :content)
    end

    test "client handler can cancel elicitation" do
      handler = TestClientHandler
      state = %{}

      message = "Please provide optional info"

      requested_schema = %{
        "type" => "object",
        "properties" => %{
          "info" => %{"type" => "string"}
        }
      }

      {:ok, result, ^state} = handler.handle_elicitation_create(message, requested_schema, state)

      assert result.action == "cancel"
      refute Map.has_key?(result, :content)
    end
  end

  describe "elicitation security considerations" do
    test "elicitation requests should not ask for sensitive information" do
      # This is a policy test - servers should not request sensitive data
      sensitive_requests = [
        "Please provide your password",
        "Please provide your credit card number",
        "Please provide your SSN",
        "Please provide your private key"
      ]

      # In a real implementation, these would be blocked or flagged
      Enum.each(sensitive_requests, fn request ->
        # Servers MUST NOT make these requests
        assert String.contains?(request, ["password", "credit card", "SSN", "private key"])
      end)
    end

    test "client should validate elicitation content against schema" do
      # Test schema validation on the client side
      _schema = %{
        "type" => "object",
        "properties" => %{
          "age" => %{"type" => "number", "minimum" => 0}
        }
      }

      valid_content = %{"age" => 25}
      invalid_content = %{"age" => -5}

      # Valid content should pass
      assert valid_content["age"] >= 0

      # Invalid content should fail
      refute invalid_content["age"] >= 0
    end

    test "rate limiting considerations" do
      # Test that elicitation requests can be rate limited
      max_requests = 5
      # 1 minute
      time_window = 60_000

      # Simulate rate limiting logic
      request_timestamps = [
        System.system_time(:millisecond),
        System.system_time(:millisecond) + 1000,
        System.system_time(:millisecond) + 2000
      ]

      recent_requests =
        Enum.count(request_timestamps, fn timestamp ->
          System.system_time(:millisecond) - timestamp < time_window
        end)

      assert recent_requests <= max_requests
    end
  end

  describe "elicitation protocol encoding" do
    test "elicitation create request is properly encoded" do
      # Test the protocol encoding function
      message = "Please provide your information"

      requested_schema = %{
        "type" => "object",
        "properties" => %{
          "name" => %{"type" => "string"}
        }
      }

      encoded = ExMCP.Internal.Protocol.encode_elicitation_create(message, requested_schema)

      assert encoded["jsonrpc"] == "2.0"
      assert encoded["method"] == "elicitation/create"
      assert encoded["params"]["message"] == message
      assert encoded["params"]["requestedSchema"] == requested_schema
      assert Map.has_key?(encoded, "id")
    end
  end

  describe "end-to-end elicitation workflow" do
    test "complete elicitation workflow" do
      # This would test the complete workflow in a real implementation
      # For now, we'll test the components separately

      # 1. Server prepares elicitation request
      message = "Please provide your contact information"

      schema = %{
        "type" => "object",
        "properties" => %{
          "email" => %{"type" => "string", "format" => "email"}
        },
        "required" => ["email"]
      }

      # 2. Request is encoded
      encoded_request = ExMCP.Internal.Protocol.encode_elicitation_create(message, schema)
      assert encoded_request["method"] == "elicitation/create"

      # 3. Client handler processes request
      handler = TestClientHandler
      state = %{}

      {:ok, response, ^state} = handler.handle_elicitation_create(message, schema, state)

      # 4. Verify response format
      assert response.action in ["accept", "reject", "cancel"]

      if response.action == "accept" do
        assert Map.has_key?(response, :content)
        assert is_map(response.content)
      end
    end
  end

  describe "type system compliance" do
    test "elicit_request type matches specification" do
      # Test that our types match the 2025-06-18 specification
      request = %{
        message: "Please provide data",
        requestedSchema: %{
          type: "object",
          properties: %{
            data: %{type: "string"}
          },
          required: ["data"]
        },
        _meta: %{timestamp: "2025-01-01T00:00:00Z"}
      }

      # Verify required fields
      assert is_binary(request.message)
      assert is_map(request.requestedSchema)
      assert request.requestedSchema.type == "object"
      assert is_map(request.requestedSchema.properties)
    end

    test "elicit_result type matches specification" do
      # Test all valid result formats
      accept_result = %{
        action: "accept",
        content: %{"data" => "test"},
        _meta: %{timestamp: "2025-01-01T00:00:00Z"}
      }

      reject_result = %{
        action: "reject",
        _meta: %{timestamp: "2025-01-01T00:00:00Z"}
      }

      cancel_result = %{
        action: "cancel"
      }

      # Verify structures
      assert accept_result.action == "accept"
      assert Map.has_key?(accept_result, :content)

      assert reject_result.action == "reject"
      refute Map.has_key?(reject_result, :content)

      assert cancel_result.action == "cancel"
      refute Map.has_key?(cancel_result, :content)
    end
  end
end
