// Copyright (c) Microsoft. All rights reserved.

// This sample shows how to use plugins with an AI agent. Plugin classes can
// depend on other services that need to be injected. In this sample, the
// AgentPlugin class uses the WeatherProvider and CurrentTimeProvider classes
// to get weather and current time information. Both services are registered
// in the service collection and injected into the plugin.
// Plugin classes may have many methods, but only some are intended to be used
// as AI functions. The AsAITools method of the plugin class shows how to specify
// which methods should be exposed to the AI agent.

using Azure.AI.Projects;
using Azure.Identity;
using Microsoft.Agents.AI;
using Microsoft.Extensions.AI;
using Microsoft.Extensions.DependencyInjection;
using SampleApp;

string endpoint = Environment.GetEnvironmentVariable("AZURE_AI_PROJECT_ENDPOINT") ?? throw new InvalidOperationException("AZURE_AI_PROJECT_ENDPOINT is not set.");
string deploymentName = Environment.GetEnvironmentVariable("AZURE_AI_MODEL_DEPLOYMENT_NAME") ?? "gpt-5.4-mini";

const string AssistantInstructions = "You are a helpful assistant that helps people find information.";
const string AssistantName = "PluginAssistant";

// Create a service collection to hold the agent plugin and its dependencies.
ServiceCollection services = new();
services.AddSingleton<WeatherProvider>();
services.AddSingleton<CurrentTimeProvider>();
services.AddSingleton<AgentPlugin>(); // The plugin depends on WeatherProvider and CurrentTimeProvider registered above.

IServiceProvider serviceProvider = services.BuildServiceProvider();

// WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
// In production, consider using a specific credential (e.g., ManagedIdentityCredential) to avoid
// latency issues, unintended credential probing, and potential security risks from fallback mechanisms.
AIProjectClient aiProjectClient = new(new Uri(endpoint), new DefaultAzureCredential());

// Create a ChatClientAgent with the options-based constructor to pass services.
AIAgent agent = aiProjectClient.AsAIAgent(new ChatClientAgentOptions
{
    Name = AssistantName,
    ChatOptions = new() { ModelId = deploymentName, Instructions = AssistantInstructions, Tools = serviceProvider.GetRequiredService<AgentPlugin>().AsAITools().ToList() }
},
    services: serviceProvider);

// Invoke the agent and output the text result.
AgentSession session = await agent.CreateSessionAsync();
Console.WriteLine(await agent.RunAsync("Tell me current time and weather in Seattle.", session));

namespace SampleApp
{
    /// <summary>
    /// The agent plugin that provides weather and current time information.
    /// </summary>
    internal sealed class AgentPlugin
    {
        private readonly WeatherProvider _weatherProvider;

        /// <summary>
        /// Initializes a new instance of the <see cref="AgentPlugin"/> class.
        /// </summary>
        /// <param name="weatherProvider">The weather provider to get weather information.</param>
        public AgentPlugin(WeatherProvider weatherProvider)
        {
            this._weatherProvider = weatherProvider;
        }

        /// <summary>
        /// Gets the weather information for the specified location.
        /// </summary>
        /// <remarks>
        /// This method demonstrates how to use the dependency that was injected into the plugin class.
        /// </remarks>
        /// <param name="location">The location to get the weather for.</param>
        /// <returns>The weather information for the specified location.</returns>
        public string GetWeather(string location)
        {
            return this._weatherProvider.GetWeather(location);
        }

        /// <summary>
        /// Gets the current date and time for the specified location.
        /// </summary>
        /// <remarks>
        /// This method demonstrates how to resolve a dependency using the service provider passed to the method.
        /// </remarks>
        /// <param name="sp">The service provider to resolve the <see cref="CurrentTimeProvider"/>.</param>
        /// <param name="location">The location to get the current time for.</param>
        /// <returns>The current date and time as a <see cref="DateTimeOffset"/>.</returns>
        public DateTimeOffset GetCurrentTime(IServiceProvider sp, string location)
        {
            CurrentTimeProvider currentTimeProvider = sp.GetRequiredService<CurrentTimeProvider>();
            return currentTimeProvider.GetCurrentTime(location);
        }

        /// <summary>
        /// Returns the functions provided by this plugin.
        /// </summary>
        /// <remarks>
        /// In real world scenarios, a class may have many methods and only a subset of them may be intended to be exposed as AI functions.
        /// This method demonstrates how to explicitly specify which methods should be exposed to the AI agent.
        /// </remarks>
        /// <returns>The functions provided by this plugin.</returns>
        public IEnumerable<AITool> AsAITools()
        {
            yield return AIFunctionFactory.Create(this.GetWeather);
            yield return AIFunctionFactory.Create(this.GetCurrentTime);
        }
    }

    internal sealed class WeatherProvider
    {
        private readonly string _weatherSummary = "cloudy with a high of 15°C";

        /// <summary>
        /// The weather provider that returns weather information.
        /// </summary>
        /// <summary>
        /// Gets the weather information for the specified location.
        /// </summary>
        /// <remarks>
        /// The weather information is hardcoded for demonstration purposes.
        /// In a real application, this could call a weather API to get actual weather data.
        /// </remarks>
        /// <param name="location">The location to get the weather for.</param>
        /// <returns>The weather information for the specified location.</returns>
        public string GetWeather(string location)
        {
            return $"The weather in {location} is {this._weatherSummary}.";
        }
    }

    internal sealed class CurrentTimeProvider
    {
        private readonly TimeProvider _timeProvider = TimeProvider.System;

        /// <summary>
        /// Provides the current date and time.
        /// </summary>
        /// <remarks>
        /// This class returns the current date and time using the system's clock.
        /// </remarks>
        /// <summary>
        /// Gets the current date and time.
        /// </summary>
        /// <param name="location">The location to get the current time for (not used in this implementation).</param>
        /// <returns>The current date and time as a <see cref="DateTimeOffset"/>.</returns>
        public DateTimeOffset GetCurrentTime(string location)
        {
            return this._timeProvider.GetLocalNow();
        }
    }
}