main.c

#include "cJSON.h"
#include <curl/curl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _WIN32
#include <windows.h>
#endif

// ================= memory buffer =================
typedef struct {
    char *data;
    size_t size;
} Buffer;

// grow buffer for HTTP response
static size_t write_cb(char *ptr, size_t size, size_t nmemb, void *ud) {
    size_t n = size * nmemb;
    Buffer *b = (Buffer *)ud;

    char *tmp = realloc(b->data, b->size + n + 1); // grow buffer
    if (!tmp) return 0;

    b->data = tmp;
    memcpy(b->data + b->size, ptr, n); // append
    b->size += n;
    b->data[b->size] = 0; // null terminate

    return n;
}

// ================= curl =================
static CURL *g_curl;

// init curl once
static int http_init() {
    if (curl_global_init(CURL_GLOBAL_ALL) != 0) return -1;
    g_curl = curl_easy_init();
    return g_curl ? 0 : -1;
}

// cleanup curl
static void http_cleanup() {
    if (g_curl) curl_easy_cleanup(g_curl);
    curl_global_cleanup();
}

// fetch wikipedia JSON
static char *http_fetch(const char *term) {
    if (!g_curl) return NULL;

    Buffer b = {0};

    // encode term => fix spaces/special chars
    char *enc = curl_easy_escape(g_curl, term, 0);
    if (!enc) return NULL;

    char url[1024];
    snprintf(url, sizeof(url),
        "https://en.wikipedia.org/w/api.php?action=query&titles=%s&prop=extracts&explaintext=1&format=json",
        enc);

    curl_free(enc);

    curl_easy_setopt(g_curl, CURLOPT_URL, url);
    curl_easy_setopt(g_curl, CURLOPT_WRITEFUNCTION, write_cb);
    curl_easy_setopt(g_curl, CURLOPT_WRITEDATA, &b);
    curl_easy_setopt(g_curl, CURLOPT_USERAGENT, "wiki-cli/1.0");
    curl_easy_setopt(g_curl, CURLOPT_TIMEOUT, 10L); // prevent hang

    if (curl_easy_perform(g_curl) != CURLE_OK) {
        free(b.data);
        return NULL;
    }

    long code = 0;
    curl_easy_getinfo(g_curl, CURLINFO_RESPONSE_CODE, &code);
    if (code != 200) { // validate HTTP
        free(b.data);
        return NULL;
    }

    return b.data; // caller frees
}

// ================= json =================

// extract "extract" field
static char *json_extract(char *json) {
    cJSON *root = cJSON_Parse(json);
    if (!root) return NULL;

    cJSON *query = cJSON_GetObjectItem(root, "query");
    if (!cJSON_IsObject(query)) goto fail;

    cJSON *pages = cJSON_GetObjectItem(query, "pages");
    if (!cJSON_IsObject(pages)) goto fail;

    cJSON *page = NULL;
    cJSON_ArrayForEach(page, pages) {
        cJSON *ext = cJSON_GetObjectItem(page, "extract");
        if (cJSON_IsString(ext) && ext->valuestring) {
            char *out = strdup(ext->valuestring); // copy result
            cJSON_Delete(root);
            return out;
        }
    }

fail:
    cJSON_Delete(root);
    return NULL;
}

// ================= cli =================

// trim newline
static void trim(char *s) {
    s[strcspn(s, "\n")] = 0;
}

#ifdef _WIN32
// enable ANSI colors on Windows
static void ansi_enable() {
    HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
    DWORD mode = 0;
    if (GetConsoleMode(h, &mode))
        SetConsoleMode(h, mode | ENABLE_VIRTUAL_TERMINAL_PROCESSING);
}
#endif

// ================= main =================
int main(int argc, char **argv) {

#ifdef _WIN32
    ansi_enable(); // allow ANSI escape codes
#endif

    if (http_init() != 0) {
        printf("[ERROR] curl init failed\n");
        return 1;
    }

    char term[256] = {0};

    // initial input
    if (argc > 1) {
        strncpy(term, argv[1], sizeof(term) - 1);
    } else {
        printf("search: ");
        if (!fgets(term, sizeof(term), stdin)) return 1;
        trim(term);
    }

    while (1) {
        char *json = http_fetch(term);
        if (!json) {
            printf("[ERROR] request failed\n");
            break;
        }

        char *text = json_extract(json);
        free(json);

        if (!text) {
            printf("[ERROR] parse failed\n");
            break;
        }

        // split first paragraph
        char *rest = NULL;
        char *split = strstr(text, "\n\n");

        if (split) {
            *split = 0;
            rest = split + 2;
        }

        printf("\n--- first ---\n%s\n", text);

        // interaction loop
        while (1) {
            printf("\n1=rest 2=new 3=exit > ");

            char buf[16];
            if (!fgets(buf, sizeof(buf), stdin)) break;

            int c = atoi(buf);

            if (c == 1 && rest) {
                printf("\n--- rest ---\n%s\n", rest);
            } else if (c == 2) {
                printf("search: ");
                if (!fgets(term, sizeof(term), stdin)) break;
                trim(term);
                break;
            } else if (c == 3) {
                free(text);
                http_cleanup();
                return 0;
            }
        }

        free(text);
    }

    http_cleanup();
    return 0;
}