/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *--------------------------------------------------------------------------------------------*/

package com.github.copilot.sdk;

import static org.junit.jupiter.api.Assertions.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;

import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;

import com.github.copilot.sdk.generated.AssistantMessageEvent;
import com.github.copilot.sdk.json.CustomAgentConfig;
import com.github.copilot.sdk.json.DefaultAgentConfig;
import com.github.copilot.sdk.json.McpServerConfig;
import com.github.copilot.sdk.json.McpStdioServerConfig;
import com.github.copilot.sdk.json.MessageOptions;
import com.github.copilot.sdk.json.PermissionHandler;
import com.github.copilot.sdk.json.ResumeSessionConfig;
import com.github.copilot.sdk.json.SessionConfig;
import com.github.copilot.sdk.json.ToolDefinition;

/**
 * Tests for MCP Servers and Custom Agents functionality.
 *
 * <p>
 * These tests use the shared CapiProxy infrastructure for deterministic API
 * response replay. Snapshots are stored in test/snapshots/mcp_and_agents/.
 * </p>
 */
public class McpAndAgentsTest {

    private static E2ETestContext ctx;

    @BeforeAll
    static void setup() throws Exception {
        ctx = E2ETestContext.create();
    }

    @AfterAll
    static void teardown() throws Exception {
        if (ctx != null) {
            ctx.close();
        }
    }

    // Helper method to create an MCP stdio server configuration
    private McpStdioServerConfig createLocalMcpServer(String command, List<String> args) {
        return new McpStdioServerConfig().setCommand(command).setArgs(args).setTools(List.of("*"));
    }

    // ============ MCP Server Tests ============

    /**
     * Verifies that MCP server configuration is accepted on session create.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_mcp_server_configuration_on_session_create
     */
    @Test
    void testShouldAcceptMcpServerConfigurationOnSessionCreate() throws Exception {
        ctx.configureForTest("mcp_and_agents", "should_accept_mcp_server_configuration_on_session_create");

        var mcpServers = new HashMap<String, McpServerConfig>();
        mcpServers.put("test-server", createLocalMcpServer("echo", List.of("hello")));

        try (CopilotClient client = ctx.createClient()) {
            CopilotSession session = client.createSession(
                    new SessionConfig().setMcpServers(mcpServers).setOnPermissionRequest(PermissionHandler.APPROVE_ALL))
                    .get();

            assertNotNull(session.getSessionId());

            // Simple interaction to verify session works
            AssistantMessageEvent response = session.sendAndWait(new MessageOptions().setPrompt("What is 2+2?")).get(60,
                    TimeUnit.SECONDS);

            assertNotNull(response);
            assertTrue(response.getData().content().contains("4"),
                    "Response should contain 4: " + response.getData().content());

            session.close();
        }
    }

    /**
     * Verifies that MCP server configuration is accepted on session resume.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_mcp_server_configuration_on_session_resume
     */
    @Test
    void testShouldAcceptMcpServerConfigurationOnSessionResume() throws Exception {
        ctx.configureForTest("mcp_and_agents", "should_accept_mcp_server_configuration_on_session_resume");

        try (CopilotClient client = ctx.createClient()) {
            // Create a session first
            CopilotSession session1 = client
                    .createSession(new SessionConfig().setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();
            String sessionId = session1.getSessionId();
            session1.sendAndWait(new MessageOptions().setPrompt("What is 1+1?")).get(60, TimeUnit.SECONDS);

            // Resume with MCP servers
            var mcpServers = new HashMap<String, McpServerConfig>();
            mcpServers.put("test-server", createLocalMcpServer("echo", List.of("hello")));

            CopilotSession session2 = client.resumeSession(sessionId, new ResumeSessionConfig()
                    .setMcpServers(mcpServers).setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();

            assertEquals(sessionId, session2.getSessionId());

            AssistantMessageEvent response = session2.sendAndWait(new MessageOptions().setPrompt("What is 3+3?"))
                    .get(60, TimeUnit.SECONDS);

            assertNotNull(response);
            assertTrue(response.getData().content().contains("6"),
                    "Response should contain 6: " + response.getData().content());

            session2.close();
        }
    }

    /**
     * Verifies that multiple MCP servers can be configured.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_mcp_server_configuration_on_session_create
     */
    @Test
    void testShouldHandleMultipleMcpServers() throws Exception {
        // Use same snapshot as single MCP server test since it doesn't depend on server
        // count
        ctx.configureForTest("mcp_and_agents", "should_accept_mcp_server_configuration_on_session_create");

        var mcpServers = new HashMap<String, McpServerConfig>();
        mcpServers.put("server1", createLocalMcpServer("echo", List.of("server1")));
        mcpServers.put("server2", createLocalMcpServer("echo", List.of("server2")));

        try (CopilotClient client = ctx.createClient()) {
            CopilotSession session = client.createSession(
                    new SessionConfig().setMcpServers(mcpServers).setOnPermissionRequest(PermissionHandler.APPROVE_ALL))
                    .get();

            assertNotNull(session.getSessionId());
            session.close();
        }
    }

    // ============ Custom Agent Tests ============

    /**
     * Verifies that custom agent configuration is accepted on session create.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_custom_agent_configuration_on_session_create
     */
    @Test
    void testShouldAcceptCustomAgentConfigurationOnSessionCreate() throws Exception {
        ctx.configureForTest("mcp_and_agents", "should_accept_custom_agent_configuration_on_session_create");

        List<CustomAgentConfig> customAgents = List.of(new CustomAgentConfig().setName("test-agent")
                .setDisplayName("Test Agent").setDescription("A test agent for SDK testing")
                .setPrompt("You are a helpful test agent.").setInfer(true));

        try (CopilotClient client = ctx.createClient()) {
            CopilotSession session = client.createSession(new SessionConfig().setCustomAgents(customAgents)
                    .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();

            assertNotNull(session.getSessionId());

            // Simple interaction to verify session works
            AssistantMessageEvent response = session.sendAndWait(new MessageOptions().setPrompt("What is 5+5?")).get(60,
                    TimeUnit.SECONDS);

            assertNotNull(response);
            assertTrue(response.getData().content().contains("10"),
                    "Response should contain 10: " + response.getData().content());

            session.close();
        }
    }

    /**
     * Verifies that custom agent configuration is accepted on session resume.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_custom_agent_configuration_on_session_resume
     */
    @Test
    void testShouldAcceptCustomAgentConfigurationOnSessionResume() throws Exception {
        ctx.configureForTest("mcp_and_agents", "should_accept_custom_agent_configuration_on_session_resume");

        try (CopilotClient client = ctx.createClient()) {
            // Create a session first
            CopilotSession session1 = client
                    .createSession(new SessionConfig().setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();
            String sessionId = session1.getSessionId();
            session1.sendAndWait(new MessageOptions().setPrompt("What is 1+1?")).get(60, TimeUnit.SECONDS);

            // Resume with custom agents
            List<CustomAgentConfig> customAgents = List
                    .of(new CustomAgentConfig().setName("resume-agent").setDisplayName("Resume Agent")
                            .setDescription("An agent added on resume").setPrompt("You are a resume test agent."));

            CopilotSession session2 = client.resumeSession(sessionId, new ResumeSessionConfig()
                    .setCustomAgents(customAgents).setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();

            assertEquals(sessionId, session2.getSessionId());

            AssistantMessageEvent response = session2.sendAndWait(new MessageOptions().setPrompt("What is 6+6?"))
                    .get(60, TimeUnit.SECONDS);

            assertNotNull(response);
            assertTrue(response.getData().content().contains("12"),
                    "Response should contain 12: " + response.getData().content());

            session2.close();
        }
    }

    /**
     * Verifies that custom agents can be configured with tools.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_custom_agent_configuration_on_session_create
     */
    @Test
    void testShouldAcceptCustomAgentWithToolsConfiguration() throws Exception {
        // Use same snapshot as create test since this just verifies configuration
        // acceptance
        ctx.configureForTest("mcp_and_agents", "should_accept_custom_agent_configuration_on_session_create");

        List<CustomAgentConfig> customAgents = List.of(new CustomAgentConfig().setName("tool-agent")
                .setDisplayName("Tool Agent").setDescription("An agent with specific tools")
                .setPrompt("You are an agent with specific tools.").setTools(List.of("bash", "edit")).setInfer(true));

        try (CopilotClient client = ctx.createClient()) {
            CopilotSession session = client.createSession(new SessionConfig().setCustomAgents(customAgents)
                    .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();

            assertNotNull(session.getSessionId());
            session.close();
        }
    }

    /**
     * Verifies that custom agents can be configured with MCP servers.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_both_mcp_servers_and_custom_agents
     */
    @Test
    void testShouldAcceptCustomAgentWithMcpServers() throws Exception {
        // Use combined snapshot since this uses both MCP servers and custom agents
        ctx.configureForTest("mcp_and_agents", "should_accept_both_mcp_servers_and_custom_agents");

        var agentMcpServers = new HashMap<String, McpServerConfig>();
        agentMcpServers.put("agent-server", createLocalMcpServer("echo", List.of("agent-mcp")));

        List<CustomAgentConfig> customAgents = List.of(new CustomAgentConfig().setName("mcp-agent")
                .setDisplayName("MCP Agent").setDescription("An agent with its own MCP servers")
                .setPrompt("You are an agent with MCP servers.").setMcpServers(agentMcpServers));

        try (CopilotClient client = ctx.createClient()) {
            CopilotSession session = client.createSession(new SessionConfig().setCustomAgents(customAgents)
                    .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();

            assertNotNull(session.getSessionId());
            session.close();
        }
    }

    /**
     * Verifies that multiple custom agents can be configured.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_custom_agent_configuration_on_session_create
     */
    @Test
    void testShouldAcceptMultipleCustomAgents() throws Exception {
        // Use same snapshot as create test
        ctx.configureForTest("mcp_and_agents", "should_accept_custom_agent_configuration_on_session_create");

        List<CustomAgentConfig> customAgents = List.of(
                new CustomAgentConfig().setName("agent1").setDisplayName("Agent One").setDescription("First agent")
                        .setPrompt("You are agent one."),
                new CustomAgentConfig().setName("agent2").setDisplayName("Agent Two").setDescription("Second agent")
                        .setPrompt("You are agent two.").setInfer(false));

        try (CopilotClient client = ctx.createClient()) {
            CopilotSession session = client.createSession(new SessionConfig().setCustomAgents(customAgents)
                    .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();

            assertNotNull(session.getSessionId());
            session.close();
        }
    }

    // ============ Combined Configuration Tests ============

    /**
     * Verifies that both MCP servers and custom agents can be configured.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_both_mcp_servers_and_custom_agents
     */
    @Test
    void testShouldAcceptBothMcpServersAndCustomAgents() throws Exception {
        ctx.configureForTest("mcp_and_agents", "should_accept_both_mcp_servers_and_custom_agents");

        var mcpServers = new HashMap<String, McpServerConfig>();
        mcpServers.put("shared-server", createLocalMcpServer("echo", List.of("shared")));

        List<CustomAgentConfig> customAgents = List.of(new CustomAgentConfig().setName("combined-agent")
                .setDisplayName("Combined Agent").setDescription("An agent using shared MCP servers")
                .setPrompt("You are a combined test agent."));

        try (CopilotClient client = ctx.createClient()) {
            CopilotSession session = client.createSession(new SessionConfig().setMcpServers(mcpServers)
                    .setCustomAgents(customAgents).setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();

            assertNotNull(session.getSessionId());

            AssistantMessageEvent response = session.sendAndWait(new MessageOptions().setPrompt("What is 7+7?")).get(60,
                    TimeUnit.SECONDS);

            assertNotNull(response);
            assertTrue(response.getData().content().contains("14"),
                    "Response should contain 14: " + response.getData().content());

            session.close();
        }
    }

    // ============ DefaultAgent Tests ============

    /**
     * Verifies that sessions can be created with defaultAgent configuration and
     * excludedTools hides tools from the default agent.
     *
     * @see Snapshot: mcp_and_agents/should_hide_excluded_tools_from_default_agent
     */
    @Test
    void testShouldHideExcludedToolsFromDefaultAgent() throws Exception {
        ctx.configureForTest("mcp_and_agents", "should_hide_excluded_tools_from_default_agent");

        try (CopilotClient client = ctx.createClient()) {
            // Register a secret_tool and exclude it from the default agent — the LLM
            // should report it has no access to the tool.
            Map<String, Object> parameters = new HashMap<>();
            parameters.put("type", "object");
            parameters.put("properties", Map.of("input", Map.of("type", "string")));
            parameters.put("required", List.of("input"));

            ToolDefinition secretTool = ToolDefinition.create("secret_tool",
                    "A secret tool hidden from the default agent", parameters,
                    invocation -> CompletableFuture.completedFuture("SECRET"));

            SessionConfig config = new SessionConfig().setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
                    .setTools(List.of(secretTool))
                    .setDefaultAgent(new DefaultAgentConfig().setExcludedTools(List.of("secret_tool")));

            CopilotSession session = client.createSession(config).get();

            assertNotNull(session.getSessionId());

            AssistantMessageEvent response = session
                    .sendAndWait(new MessageOptions()
                            .setPrompt("Do you have access to a tool called secret_tool? Answer yes or no."))
                    .get(60, TimeUnit.SECONDS);

            assertNotNull(response);
            assertTrue(response.getData().content().toLowerCase().contains("no"),
                    "Response should indicate that secret_tool is not accessible: " + response.getData().content());
            session.close();
        }
    }

    /**
     * Verifies that defaultAgent configuration is accepted on session resume.
     *
     * @see Snapshot:
     *      mcp_and_agents/should_accept_defaultagent_configuration_on_session_resume
     */
    @Test
    void testShouldAcceptDefaultAgentConfigurationOnSessionResume() throws Exception {
        ctx.configureForTest("mcp_and_agents", "should_accept_defaultagent_configuration_on_session_resume");

        try (CopilotClient client = ctx.createClient()) {
            CopilotSession session = client
                    .createSession(new SessionConfig().setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get();

            assertNotNull(session.getSessionId());
            String sessionId = session.getSessionId();
            // Do not call session.close() here — that invokes session.destroy on the
            // server,
            // which removes the session and causes the subsequent resumeSession to fail
            // with "Session not found". The session handle is simply abandoned and the
            // server-side session remains alive for the resume call below.

            CopilotSession resumedSession = client.resumeSession(sessionId,
                    new ResumeSessionConfig().setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
                            .setDefaultAgent(new DefaultAgentConfig().setExcludedTools(List.of("view"))))
                    .get();

            assertNotNull(resumedSession.getSessionId());

            AssistantMessageEvent response = resumedSession.sendAndWait(new MessageOptions().setPrompt("What is 3+3?"))
                    .get(60, TimeUnit.SECONDS);

            assertNotNull(response);
            resumedSession.close();
        }
    }
}