NTestAIApi/Controllers/AIController.cs

using Google.GenAI.Types;
using Microsoft.AspNetCore.Mvc;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace NTestAIApi.Controllers {
    [Route("api/[controller]")]
    [ApiController]
    public class AIController : ControllerBase {
        private readonly IHttpClientFactory _httpClientFactory;
        private readonly IConfiguration _configuration;

        public AIController(IHttpClientFactory httpClientFactory, IConfiguration configuration) {
            _httpClientFactory = httpClientFactory;
            _configuration = configuration;
        }

        [HttpGet(Name = "GetAI")]
        public async Task<IActionResult> Get([FromQuery] string question, [FromQuery] string? answer, [FromQuery] int? id) {
            var apiKey = _configuration["Gemini:ApiKey"];
            if (string.IsNullOrWhiteSpace(apiKey)) {
                return StatusCode(500, "Gemini API 키가 설정되지 않았습니다.");
            }

            var url = "https://generativelanguage.googleapis.com/v1beta/models/gemini-flash-latest:generateContent";
            var prompt = $"문제: {question}\n정답: {answer}\n이 문제와 정답이 맞는지 간단히 설명해줘.";

            var requestBody = new GeminiRequest {
                Contents = new List<Content>
                {
                    new Content
                    {
                        Parts = new List<Part>
                        {
                            new Part
                            {
                                Text = prompt
                            }
                        }
                    }
                }
            };

            var client = _httpClientFactory.CreateClient();

            using var requestMessage = new HttpRequestMessage(HttpMethod.Post, url);
            requestMessage.Headers.Add("X-goog-api-key", apiKey);
            requestMessage.Content = new StringContent(JsonSerializer.Serialize(requestBody), Encoding.UTF8, "application/json");

            var response = await client.SendAsync(requestMessage);
            var responseText = await response.Content.ReadAsStringAsync();

            if (!response.IsSuccessStatusCode) {
                return StatusCode((int)response.StatusCode, responseText);
            }

            var geminiResponse = JsonSerializer.Deserialize<GeminiResponse>(responseText);

            var resultText = geminiResponse?
                .Candidates?
                .FirstOrDefault()?
                .Content?
                .Parts?
                .FirstOrDefault()?
                .Text;

            return Ok(new {
                prompt,
                result = resultText ?? "",
                raw = geminiResponse
            });
        }
    }

    public class GeminiRequest {
        [JsonPropertyName("contents")]
        public List<Content> Contents { get; set; } = new();
    }

    public class Content {
        [JsonPropertyName("parts")]
        public List<Part> Parts { get; set; } = new();
    }

    public class Part {
        [JsonPropertyName("text")]
        public string Text { get; set; } = "";
    }

    public class GeminiResponse {
        [JsonPropertyName("candidates")]
        public List<Candidate>? Candidates { get; set; }
    }

    public class Candidate {
        [JsonPropertyName("content")]
        public CandidateContent? Content { get; set; }
    }

    public class CandidateContent {
        [JsonPropertyName("parts")]
        public List<Part>? Parts { get; set; }
    }
}