#include <stdbool.h>
#include <stdio.h>
#include <string.h>

#include "str_replace_start.h"

#define LIBRE_N 19

/* Uncomment for debug */
/* #define DEBUG */

/* Inspired by https://libredirect.github.io/, but in C. */

void str_init(char* str, int n)
{
    for (int i = 0; i < n; i++)
        str[i] = ' ';
    str[n] = '\0';
} // could also use <https://manpages.ubuntu.com/manpages/impish/man3/strinit.3pub.html>

int libre_redirect(const char* uri, char* output)
{
    int l1 = strlen(uri);
    int l2 = strlen(output);
    int len;
    char tmp_uri[l2++];
    char tmp_output[l2++];

    if ((l2 - l1) < LIBRE_N) {
#ifdef DEBUG
        printf("Not enough memory\n");
#endif
        return 1; // not enough memory.
    } else {
        strcpy(tmp_uri, uri); // strcpy also copies the terminating '\0'
        strcpy(tmp_output, output);

        char* annoying_sites[] = {
            "https://www.youtube.com",
            "https://www.reddit.com",
            "https://medium.com",
            "https://translate.google.com",
            "https://ea.greaterwrong.com/posts", // "https://forum.effectivealtruism.org/posts",
            "https://www.bloomberg.com",
            "https://twitter.com"
        };

        char* alternatives[] = {
            "https://yt.artemislena.eu",
            "https://teddit.nunosempere.com",
            "https://scribe.rip",
            "https://simplytranslate.org/",
            "https://trastos.nunosempere.com/ea-forum/posts", // "https://ea.greaterwrong.com",
            "https://archive.is/https://www.bloomberg.com",
            "https://nitter.net"
        };

        len = sizeof(annoying_sites) / sizeof(annoying_sites[0]);

        for (int i = 0; i < len; i++) {
            int replace_check = str_replace_start(tmp_uri, annoying_sites[i],
                alternatives[i], output);
            if (replace_check == 2) {
#ifdef DEBUG
                printf("tmp_uri: %s\n", tmp_uri);
                printf("output: %s\n", output);
#endif
                return 2;
            } else if (replace_check == 1) {
#ifdef DEBUG
                printf("replace_check failed\n");
#endif
                return 1;
            }
            strcpy(tmp_uri, output);
            str_init(output, l2);
        }
        strcpy(output, tmp_uri);
    }
#ifdef DEBUG
    printf("No match found\n\n");
#endif
    return 0;
}