82 lines
2.7 KiB
C#
82 lines
2.7 KiB
C#
using System.Net.Http.Json;
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using System.Text.Json;
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using LeetCodeSharp.Fetcher.Models;
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namespace LeetCodeSharp.Fetcher;
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internal class Fetcher
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{
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private const string ProblemsUrl = "https://leetcode.cn/api/problems/algorithms/";
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private const string GraphQlUrl = "https://leetcode.cn/graphql";
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private readonly HttpClient _httpClient = new();
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private readonly JsonSerializerOptions _serializerOptions = new()
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{
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PropertyNameCaseInsensitive = true,
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PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower
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};
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public async Task<Problems> GetProblems()
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{
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var problems =
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await _httpClient.GetFromJsonAsync<Problems>(ProblemsUrl, _serializerOptions)
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?? throw new Exception("Failed to get problems.");
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return problems;
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}
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public async Task<Problem> GetProblem(uint questionId)
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{
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var problems = await GetProblems();
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var targetProblem = problems.StatStatusPairs.First(p =>
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{
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if (uint.TryParse(p.Stat.FrontendQuestionId, out var id))
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{
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return id == questionId;
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}
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return false;
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});
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if (targetProblem.PaidOnly)
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{
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throw new Exception("Target problem is paid only.");
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}
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if (targetProblem.Stat.QuestionTitleSlug is null)
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{
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throw new Exception("Failed to get problem title.");
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}
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var query = new Query(targetProblem.Stat.QuestionTitleSlug);
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var response = await _httpClient.PostAsJsonAsync(
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GraphQlUrl, query, _serializerOptions);
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response.EnsureSuccessStatusCode();
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var rawProblem = await JsonSerializer.DeserializeAsync<RawProblem>(
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await response.Content.ReadAsStreamAsync(), _serializerOptions)
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?? throw new Exception("Failed to get raw problem.");
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var returnType = rawProblem.Data.Question.MetaData.Replace("\"", "");
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return new Problem
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{
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Title = targetProblem.Stat.QuestionTitle
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?? throw new Exception("Failed to get question title"),
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TitleSlug = targetProblem.Stat.QuestionTitleSlug
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?? throw new Exception("Failed to get question title slug"),
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Content = rawProblem.Data.Question.Content,
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QuestionId = questionId,
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ReturnType = returnType,
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CodeDefinition = JsonSerializer.Deserialize<List<CodeDefinition>>(
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rawProblem.Data.Question.CodeDefinition, _serializerOptions)
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?? throw new Exception("Failed to get code definition.")
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};
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}
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}
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