#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include "7ed.h"
#include <stdint.h>

int write_line(char filename[], long focus, char editbuffer[], size_t editbuffer_size) {

    char *line;
    size_t start;
    int ret = GET_LINE(filename, focus, &line, &start); // get start position of focus
    if (ret == 1) {
        return EXIT_FAILURE;
    }

    FILE *file;
    FILE *temp;
    file = fopen(filename,"r"); // Open file
    temp = fopen("temp.7ed","w+");
    if (file == NULL || temp == NULL) { // Check if you can open file
        fprintf(stderr, "Cannot open file. write_line\n");
        return 1;
    }

    fseek(file, start, SEEK_SET);
    size_t count = 0;
    while (1) {
        char c = fgetc(file);
        if (c == '\n') {
            break;               // count the length of the specific line to be replaced
        } else if (c == EOF) {
            break;
        } else {
            count++;
        }
    }

    fseek(file, 0, SEEK_SET); // go to start of file
    size_t counter = 0;
    char ch;
    for (;; counter++) {  // for loop that puts contents of file in to temp
                        // when counter is equal to start, the buffer with the edited content is written to temp
        if (start == counter) { // after that it uses fseek to point temp right after the written content
            fprintf(temp, "%s", editbuffer); // and fseek on file will use count variable to skip the content that is supposed to be replaced
            fseek(temp, start+editbuffer_size-1, SEEK_SET); // After that the function keeps writing everything else to temp
            fseek(file, start+count, SEEK_SET);
        }
        ch = fgetc(file);
        if (ch == EOF) {
            break;
        }
        fputc(ch, temp);

    }
    fseek(temp, 0, SEEK_SET); // reset both files to start at 0 so it doesnt mess with fread and fwrite
    fclose(file);
    file = fopen(filename, "w");
    if (file == NULL) { // Check if you can open file
        fprintf(stderr, "Cannot open file for writing.\n");
        return 1;
    }
    char buffer[BUF_SZ_2];
    size_t bytes_read;
    while ((bytes_read = fread(buffer, 1, BUF_SZ_2, temp)) > 0) { // Write contents of temp to file
        fwrite(buffer, 1, bytes_read, file);
    }
    free(line);
    fclose(file);
    fclose(temp);
    remove("temp.7ed");
    return 0;

}

int check_end_newline(char filename[]) {

    FILE *file; 
    file = fopen(filename, "r");
    if (file == NULL) {
        fprintf(stderr, "Cannot open file. check_end_newline()\n");
        return 1;
    }

    fseek(file, -1, SEEK_END);
    if (fgetc(file) != '\n') {
        return -1; // returns -1 if there is not newline at the end
    }
    fclose(file);
    return 0; // returns 0 if there is one

}

int NEW_LINE(char filename[]) { // doin this test again

    long new_line_pos; // The "focus" that the newline will be inserted afterwards
    long new_line_pos_temp = 0; // temp
    char buf[1024];
    int success;

    do {
        fprintf(stdout, "Create a new line after: ");
        if (!fgets(buf, 1024, stdin)) {    // take input from user
            fprintf(stderr, "Too many characters\n");
            break;
        }
        char *endptr;

        new_line_pos_temp = strtol(buf, &endptr, 10);
        errno = 0;
        if (errno == ERANGE) {
            fprintf(stderr, "Sorry, this number is too small or too large.\n");
            success = 0;
        }
        else if (endptr == buf) {
            // no character was read
            success = 0;
        }
        else if (*endptr && *endptr != '\n') {
            success = 0;
        }

        else {
            success = 1;
        }

        } while (!success);

        if (new_line_pos_temp < 0) {
            fprintf(stderr, "The new line can not be under 0!\n");
            return 1;
        } else {
            new_line_pos = new_line_pos_temp;

            int cen = check_end_newline(filename);
            if (cen == -1) {
                size_t linecount;
                int clif = COUNT_LINES_IN_FILE(filename, &linecount);
                if (clif == 1) {
                    return 1;
                }
                if (linecount == (size_t)new_line_pos) {
                    FILE *file;
                    file = fopen(filename, "a");
                    fputc('\n', file);
                    fclose(file);
                    return 0;
                }

            }
            printf("continuing\n");
            char *line; // line is the line before the newline
                                // line2 is the line right after line
            size_t start; // start is the position at the start of line
                                  // start2 is the position at the start of line2
            int ret = GET_LINE(filename, new_line_pos+1, &line, &start);
            if (ret == 1) {
                return 1;
            }

            size_t len = strlen(line);
            char to_be_written[len+2];
            to_be_written[0] = '\n';
            to_be_written[1] = '\0';
            strcat(to_be_written, line);
            
            write_line(filename, new_line_pos+1, to_be_written, len+1);
            free(line);
        }

    return 0;

}

int editmode(char filename[], long focus) {

    char *line;
    size_t start;
    int ret = GET_LINE(filename, focus, &line, &start);
    if (ret == 1) {
        return EXIT_FAILURE;
    }

    fprintf(stdout, "%s", line); // print line to be edited
    free(line);

    while (1) {
        char editbuffer[BUF_SZ_2];
        fprintf(stdout, "(%ld EDIT): ", focus);

        fgets(editbuffer, BUF_SZ_2, stdin);

        if (editbuffer[0] == '\n') { continue; }

        fprintf(stdout, "Do you want to write the changes?\n");
        int yesno = CHOICE();

        if (yesno == 1) {
            printf("N\n");
            return 0;
        }
        
        size_t editbuffer_size = strlen(editbuffer);
        write_line(filename, focus, editbuffer, editbuffer_size);

        return 0;

    }

    return EXIT_SUCCESS;

}