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

#define MAXCMD 256
#define MAXLINE 2048
#define MAXLINELEN 256

char file[MAXLINE][MAXLINELEN];
int linecount = 0;

char command[MAXCMD];
int cmdlen;

int lineno = 0; 

void eprint(char *str) {
        fprintf(stderr, "%s\n", str);
        exit(1);
}

void readcmd() {
	printf("%d > ", lineno);
        char c;
        while ((c = getchar()) != '\n' && cmdlen <= MAXCMD) {
                command[cmdlen] = c;
                cmdlen++;
        }
        command[cmdlen] = 0;
}

void emptystr(char *s) {
        for (int i = 0; i < strlen(s); i++)
                s[i] = 0;
 }

void emptycmd() {
	emptystr(command);
        cmdlen = 0;
}

void readfile(FILE *f) {
        int i = 0;
        char c;
        while ((c = fgetc(f)) != EOF) {
                if (c == '\n') {
                        file[linecount][i] = 0;
                        linecount++;
                        i = 0;
                } else {
	                file[linecount][i] = c;
	                i++;
                }
        }
}

void printfile(FILE *out, bool numbers) {
        for (int i = 0; i < linecount; i++) {
	        if (!numbers) fprintf(out, "%s\n", file[i]);
        	else fprintf(out, "%d: %s\n", i, file[i]);
        }
}

int readnum() { 
	if (isdigit(command[0])) {
		char num[MAXCMD] = {0};
		int i;
		for (i = 0; i < cmdlen && isdigit(command[i]); i++) {
			num[i] = command[i];
		}
		num[i] = 0;
		return atoi(num);
	}
	return -1;
}

void deleteline(int n) {
	char nfile[MAXLINE][MAXLINELEN];
	int nlinecount = 0;
	for (int i = 0; i < linecount; i++) {
		if (i != n) {
			strcpy(nfile[nlinecount], file[i]);
			nlinecount++;
		}
	}

	for (int i = 0; i < nlinecount; i++) {
		emptystr(file[i]);
		strcpy(file[i], nfile[i]);
	}
	linecount--;
}

void runcmd(char *outpath) {
	FILE *f;

	int n;
	if ((n = readnum()) != -1) {
		if (n > linecount) {
			printf("?\n");
			goto repeat;
		}
		lineno = n;
	}

	int i = 0;
repeat:
	switch (command[i]) {
		case 0:
			return;
		case 'd':
			deleteline(lineno);
			break;
		case 'P':
			printfile(stdout, false);
			break;
		case 'N':
			printfile(stdout, true);
			break;
		case 'w':
			f = fopen(outpath, "w");
			printfile(f, false);
			fclose(f);
			break;
		case 'q':
			exit(1);
	}
	i++;
	goto repeat;
}

int main(int argc, char **argv) {
	FILE *f;
        if (argc > 1) {
                FILE *f = fopen(argv[1], "r+");
                if (f == NULL) eprint("failed to open file");
                readfile(f);
                fclose(f);
        } 
        else eprint("no file given");

        for (;;) {
                readcmd();
                runcmd(argv[1]);
                emptycmd();
        }
}