init repo.

include/fetcher.h

@@ -0,0 +1,126 @@
+//
+// Created by ricardo on 12/06/25.
+//
+
+#ifndef FETCHER_H
+#define FETCHER_H
+#include <iostream>
+#include <memory>
+#include <curl/curl.h>
+#include <nlohmann/json.hpp>
+
+struct CurlDeleter
+{
+    void operator()(CURL *curl) const
+    {
+        if (curl != nullptr)
+        {
+            curl_easy_cleanup(curl);
+        }
+    }
+};
+
+struct LeetCodeProblem
+{
+    LeetCodeProblem(bool paidOnly,
+                    std::string frontendQuestionId,
+                    int questionId,
+                    std::string questionTitle,
+                    std::string questionTitleSlug)
+        : paidOnly(paidOnly)
+        , frontendQuestionId(std::move(frontendQuestionId))
+        , questionId(questionId)
+        , questionTitle(std::move(questionTitle))
+        , questionTitleSlug(std::move(questionTitleSlug))
+    {
+    }
+
+    bool paidOnly;
+    std::string frontendQuestionId;
+    int questionId;
+    std::string questionTitle;
+    std::string questionTitleSlug;
+};
+
+struct CodeDefinition
+{
+    std::string value;
+    std::string text;
+    std::string defaultCode;
+
+    CodeDefinition(std::string value, std::string text, std::string defaultCode)
+        : value(std::move(value))
+        , text(std::move(text))
+        , defaultCode(std::move(defaultCode))
+    {
+    }
+};
+
+struct ProblemContent
+{
+    std::string title;
+    std::string title_slug;
+    std::string content;
+    std::vector<CodeDefinition> codeDefinitions;
+    int questionId;
+
+    ProblemContent(std::string title,
+                   std::string title_slug,
+                   std::string content,
+                   std::vector<CodeDefinition> codeDefinitions,
+                   int questionId)
+        : title(std::move(title))
+        , title_slug(std::move(title_slug))
+        , content(std::move(content))
+        , codeDefinitions(std::move(codeDefinitions))
+        , questionId(questionId)
+    {
+    }
+
+    std::string formatTemplate(const std::string &templateContent) const;
+};
+
+struct Fetcher
+{
+    Fetcher()
+    {
+        // Initialize the cURL global environment.
+        curl_global_init(CURL_GLOBAL_ALL);
+        client = std::unique_ptr<CURL, CurlDeleter>(curl_easy_init());
+    }
+
+    ~Fetcher()
+    {
+        curl_global_cleanup();
+    }
+
+    void fetchProblem(const std::string &idString) const;
+
+private:
+    std::unique_ptr<CURL, CurlDeleter> client;
+
+    std::string kProblemsUrl = "https://leetcode.cn/api/problems/algorithms/";
+    std::string kGraphQlUrl = "https://leetcode.cn/graphql";
+
+    [[nodiscard]] std::vector<LeetCodeProblem> getProblems() const;
+
+    /// The callback function used by curl to write the http response content into a string.
+    static size_t httpWriteCallback(void *contents, const size_t size, size_t bufferLength, void *userData)
+    {
+        auto string = static_cast<std::string *>(userData);
+        auto body = static_cast<char *>(contents);
+        string->append(body, size * bufferLength);
+
+        return size * bufferLength;
+    }
+
+    static nlohmann::json formatQueryJson(const std::string &title);
+
+    static std::unique_ptr<ProblemContent> extractContentFromJson(
+        const nlohmann::json &json,
+        const LeetCodeProblem &problem);
+
+    static std::string readTemplateFile();
+};
+
+#endif //FETCHER_H