/* Melee fleet randomizer for the  Star Control II rerelease, 
 * Ur-Quan Masters.
 * 
 * (c) 1996, 2002 Juho Snellman <jsnell@iki.fi>
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <stdarg.h>

enum { MAX_FLEET = 14 };
enum { FLEET_ARRAY_SIZE = 70 };

typedef struct {
    int  id;
    int  price;
    char name[9];
}
ship_s;

typedef struct {
    char *name;
    int  cost;
} fleet_s; 

static int SHIPS = 25;

ship_s ships[] = {
    { 13,  5, "shofixti" },
    { 24,  6, "zoqfot" },
    { 19,  7, "umgah" },
    { 18, 10, "thradd" },
    { 6,  10, "ilwrath" },
    { 5,  11, "human" },
    { 22, 12, "vux" },
    { 17, 13, "syreen" },
    { 0,  15, "androsyn" },
    { 1,  16, "arilou" },
    { 16, 16, "supox" },
    { 14, 17, "slylandr" },
    { 4,  17, "druuge" },
    { 15, 18, "spathi" },
    { 8,  18, "melnorme" },
    { 9,  19, "mmrnmhrm" },
    { 10, 21, "mycon" },
    { 12, 20, "pkunk" },
    { 21, 22, "utwig" },
    { 11, 23, "orz" },
    { 23, 23, "yehat" },
    { 2,  28, "chenjesu" },
    { 3,  30, "chmmr" },
    { 20, 30, "urquan" },
    { 7,  30, "blackurq" },
};

void die (char* format, ...) {
    va_list argp;
    
    va_start(argp, format);
    vfprintf(stderr, format, argp);
    va_end(argp);
    
    exit(EXIT_FAILURE);
}

char *fleet_name(char *fleet) {
    fprintf(stderr, "%s\n", fleet);
    return strdup(&fleet[MAX_FLEET]);
}

int random_ship (int min_cost, int max_cost) {
    int top = 0; 
    int bottom = 0;
    
    if (min_cost > max_cost) {
	die("Internal error. Tried to create ship of max_cost %d, min_cost %d\n", max_cost, min_cost);
    }

    for (; top < SHIPS; top++) {
	if (ships[top].price < min_cost)
	  bottom++;
	if (ships[top].price > max_cost)
	  break;
    }
    
    if (top == 0) {
	die("Internal error. Tried to create ship of cost %d\n", max_cost);
    }
    
    return rand() % (top-bottom) + bottom;
}

int find_cheap_slots (int fleet[MAX_FLEET], int cheap_slots[MAX_FLEET]) {
    int i = 0;
    int j = 0;
    
    for (i = 0; i < MAX_FLEET; i++) {	
	if (ships[fleet[i]].price < ships[SHIPS-1].price)
	  cheap_slots[j++] = i;
    }
    
    return j;
}

void generate_ships (char *fleet_str, int limit) {
    int gen = 0;
    int cost = 0;    
    int fleet[MAX_FLEET];
    int j;
    
    // fprintf(stderr, "New fleet (%d)\n", limit);
    while (gen < MAX_FLEET && cost < limit - ships[0].price) {
	int i = random_ship(0, limit - cost);
	fleet[gen] = i;
	cost += ships[i].price;
	// fprintf(stderr, "Created '%s'\n", ships[fleet[gen]].name);
	gen++;
    }
    
    while (cost < limit - ships[0].price) {
	int cheap_slots[MAX_FLEET];
	int amount = find_cheap_slots(fleet, cheap_slots);
	int r;
	
	if (amount == 0)
	  die("Impossible to create fleet worth %d points (got to %d)\n", limit, cost);
	
	r = cheap_slots[rand() % amount];
	// fprintf(stderr, "Replacing '%s' with ", ships[fleet[r]].name);
	cost -= ships[fleet[r]].price;
	fleet[r] = random_ship(ships[fleet[r]].price + 1, limit - cost);
	cost += ships[fleet[r]].price;
	// fprintf(stderr, "'%s'\n", ships[fleet[r]].name);
    }
    
    fprintf(stderr, "Generated fleet for %d points\n", cost);
    
    for (j = 0; j < gen; j++)
      fleet_str[j] = ships[fleet[j]].id;
}

void replace_fleet (char *fleet, int limit) {
    fleet++;
    memset(fleet, 0xff, MAX_FLEET);
    generate_ships(fleet, limit);    
}

void read_melee_cfg (int p1, int p2, char *fname) {
    FILE *f = fopen(fname, "r+b");
    char melee_cfg[141];
    int len;
    
    if (f == NULL)
      die("Error opening %s: %s\n", fname, strerror(errno));
    
    len = fread(melee_cfg, 1, sizeof(melee_cfg), f);
    
    if (len < 140)
      die("Expected %d bytes from melee.cfg, only got %d\n", 
	  140, len);
    if (!feof(f))
      die("melee.cfg not exactly 140 bytes long\n");
    
    replace_fleet(&melee_cfg[0], p1);
    replace_fleet(&melee_cfg[FLEET_ARRAY_SIZE], p2);
    
    fseek(f, 0, SEEK_SET);
    fwrite(melee_cfg, 1, 106, f);
    fclose(f);
}

void remove_ship (char *shipname) {
    int i;
    
    for (i = 0; i < SHIPS; i++) {
	if (strcmp(ships[i].name, shipname) == 0)
	  break;
    }
    
    if (i == SHIPS)
      die("No ship '%s' found\n", shipname);
    
    memmove(&ships[i], &ships[i+1], sizeof(ship_s)*(SHIPS-1-i));
    SHIPS--;    
}


void list_ships () {
    int i;
    
    for (i = 0; i < SHIPS; i++) {
	printf("%-9s (%d)\n", ships[i].name, ships[i].price);
    }
    exit(0);
}

int mstrtol (char *s) {
    char *end;
    int i = strtol(s, &end, 10);
    
    if (*end != '\0')
      die("Invalid number: %s\n", s);
    
    return i;
}

void usage (char *name) {
    die("Usage: %s [options]\n"
	"  Options:\n"
	"    -1 number    maximum cost of fleet 1 (defaults to 150)\n"
	"    -2 number    maximum cost of fleet 2 (defaults to 150)\n"
	"    -e shipname  don't generate any 'shipname':s in either fleet\n"
	"    -f filename  path to melee.cfg (default to ~/.uqm/melee.cfg\n"
	"    -h           this message\n"
	"    -l           list all valid shipnames, then quit\n"
	"\n"
	"Send bug reports and feature requests to <jsnell@iki.fi>.\n"
	, 
	name);
}

int main (int argc, char **argv) {
    int p1 = 150, p2 = 150;
    char *fname = NULL;
    int i = 1;
    srand(time(NULL));    
    
    while (i < argc) {
	if (strcmp(argv[i], "-1") == 0) {
	    p1 = mstrtol(argv[++i]);
	} else if (strcmp(argv[i], "-2") == 0) {
	    p2 = mstrtol(argv[++i]);    
	} else if (strcmp(argv[i], "-e") == 0) {
	    remove_ship(argv[++i]);
	} else if (strcmp(argv[i], "-f") == 0) {
	    fname = argv[++i];
	} else if (strcmp(argv[i], "-f") == 0) {
	    usage(argv[0]);
	} else if (strcmp(argv[i], "-l") == 0) {
	    list_ships();
	} else {
	    fprintf(stderr, "Invalid parameter: %s\n", argv[i]);
	    usage(argv[0]);
	}
	
	i++;
    }
    
    if (fname == NULL) {
	char *home = getenv("HOME");
	
	if (home == NULL)
	  die("No path to melee.cfg given, and HOME not set\n");
	
	fname = malloc(strlen(home) + 16);
	sprintf(fname, "%s%s", home, "/.uqm/melee.cfg");
	
	fprintf(stderr, "No path to melee.cfg given. Defaulting to '%s'.\n", fname);
    }
    
    read_melee_cfg(p1, p2, fname);
    
    return 0;
}