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

#define MAX_LINE 10000

FILE* f = 0;
FILE* g = 0;
bool sure = false;
char cur_file[50];
bool modified;

void closefile()
{
    if (f != 0)
    {
        for (;;)
        {
            char ch = fgetc(f);
            if (feof(f))
                break;
            putc(ch, g);
        }
        fclose(f);
        fclose(g);
        if (sure && modified)
        {
            f = fopen(cur_file, "wt");
            g = fopen("multifilefixtempfile.txt", "rt");
            for (;;)
            {
                char ch = fgetc(g);
                if (feof(g))
                    break;
                putc(ch, f);
            }
            fclose(f);
            fclose(g);
        }
    }
}

int main(int argc, char *argv[])
{
    sure = argc == 2 && strcmp(argv[1], "-sure") == 0;
    
    cur_file[0] = '\0';
    int cur_linenr;
    
    char buffer[MAX_LINE];
    
    while (fgets(buffer, MAX_LINE, stdin))
    {
        //printf("Process: %s", buffer);
        char *s = strstr(buffer, "\r\n");
        if (s != 0)
            strcpy(s, "\n");
        
        s = buffer;
        while (*s != ':' && *s != '\0')
            s++;
        if (*s == '\0')
        {
            printf("Error: %s\n", buffer);
            return 1;
        }
        *s++ = '\0';

        int linenr = atoi(s);

        while (*s != ':' && *s != '\0')
            s++;
        if (*s == '\0')
        {
            printf("Error: %s\n", buffer);
            return 1;
        }
        s++;
        
        if (strcmp(cur_file, buffer) != 0)
        {
            closefile();            
            strcpy(cur_file, buffer);
            //printf("Open file: '%s'\n", cur_file);
            f = fopen(cur_file, "rt");
            g = fopen("multifilefixtempfile.txt", "wt");
            cur_linenr = 1;
            modified = false;
        }
        while (cur_linenr < linenr)
        {
            for (;;)
            {
                char ch = fgetc(f);
                if (feof(f))
                    break;
                putc(ch, g);
                if (ch == '\n')
                    break;
            }
            cur_linenr++;
            if (feof(f))
            {
                printf("Error: no line %d (at %d) in :%s\n", linenr, cur_linenr, buffer);
                return 1;
            }
        }
        char buffer2[MAX_LINE];
        fgets(buffer2, MAX_LINE, f);
        if (strcmp(s, buffer2) != 0)
        {
            printf("In file %s, line %d, replace:\n%s%s\n", cur_file, cur_linenr, buffer2, s);
            modified = true;
        }
        fprintf(g, "%s", s);
        cur_linenr++;
    }
    closefile();
}