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

struct common_state {};

enum class editmode {
    readonly,
    edit,
};


common_state* common_state_new(void);
void ideas(void) 
{
    struct common_state *common = common_state_new();
    system(common_state_get_wv_ideas(common));
}
void stats(void)     
{
}
void ls(long n)      {}
void ls_html(void)
{
    common_state *common = common_state_new();
    // TODO: implement, by using dirent and iterating over the dir. 
    // Return the HTML, organised by date (reading the first line of each file)
    // and with the word count. This is a trivially parallelizable problem.
}
void per_day(void)   {}
void per_month(void) {}
void readedit(enum editmode em, long n) {}
    

noreturn void usage(void) 
{
    printf("wv\n");
    printf("Flags:\n");
    printf("Commands:\n");
    printf("    If no command passed, open the next wv entry for writing.\n");
    printf("    help      Display this help message.\n");
    printf("    ideas     Edit the `ideas` file.\n");
    printf("    stats     Display entries, wordcount and average wordcount.\n");
    printf("    ls (N)    Display the (N most recent) entries.\n");
    printf("    ls-html   Display the entries as HTML.\n");
    printf("    per-day   The amount of entries written per day.\n");
    printf("    per-month The amount of entries written per month.\n");
    printf("    read ENT  Read an entry without being able to edit it.\n");
    printf("    ENT       Edit the entry number.\n");
    exit(0);
}

int main(int argc, char **argv)
{
    if (argc < 1)
    {
	fprintf(stderr, "too few arguments\n");
	exit(-1);
    }

    const char *cmd = argv[1];
    if (!strcmp(cmd, "help")) 
	usage();
    else if (!strcmp(cmd, "ideas")) 
	ideas();
    else if (!strcmp(cmd, "stats"))
	stats();
    else if (!strcmp(cmd, "ls"))
    {
	if (argc == 2)
	{
	    ls(LONG_MAX);
	}
	else
	{
	    long n = strtol(cmd[2], NULL, 10);
	    if (n <= 0) 
	    {
		fprintf(stderr, "Must provide a positive integer to ls, provided %s\n", cmd[2]);
		exit(-1);
	    }
	    ls(n);
	}
    }
    else if (!strcmp(cmd, "ls-html"))
	ls_html();
    else if (!strcmp(cmd, "per-day"))
	per_day();
    else if (!strcmp(cmd, "per-month"))
	per_month();
    else
    {
	const char *ent;
	enum editmode em;

	if (!strcmp(cmd, "read") || !strcmp(cmd, "edit"))
	{
	    if (argc == 2)
	    {
		fprintf(stderr, "%s command must have entry number\n", cmd);
		exit(-1);
	    }

	    em = !strcmp(cmd, "read") ? editmode::readonly : editmode::edit;
	    ent = argv[2];
	} 
	else 
	{
	    em = em_edit; 
	    ent = argv[1];
	}

	long n = strtol(ent, NULL, 10);
	if (n < 0)
	{
	    fprintf(stderr, "Entry must be a positive number, instead received %s\n", ent);
	    exit(-1);
	}

	readedit(em, n);
    }
}