#include <u.h>
#include <libc.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>
#include <stdio.h>
#include <dirent.h>
#include <libString.h>
#include <mp.h>
#include <libsec.h>

#define CARTSLOC "./carts/"
#define CTL_HASHV 139931
#define SHUTDOWN_HASHV 11192337284248
/* clang-format off */

char  clca(char c) { return c >= 'A' && c <= 'Z' ? c + ('a' - 'A') : c; } /* char to lowercase */
char  cuca(char c) { return c >= 'a' && c <= 'z' ? c - ('a' - 'A') : c; } /* char to uppercase */
int   slen(char *s) { int i = 0; while(s[i] && s[++i]) { ; } return i; } /* string length */
char *st__(char *s, char (*fn)(char)) { int i = 0; char c; while((c = s[i])) s[i++] = fn(c); return s; }
char *stuc(char *s) { return st__(s, cuca); } /* string to uppercase */
char *stlc(char *s) { return st__(s, clca); } /* string to lowercase */
char *scpy(char *src, char *dst, int len) { int i = 0; while((dst[i] = src[i]) && i < len - 2) i++; dst[i + 1] = '\0'; return dst; } /* string copy */
int   scmp(char *a, char *b) { int i = 0; while(a[i] == b[i]) if(!a[i++]) return 1; return 0; } /* string compare */
char *scsw(char *s, char a, char b) { int i = 0; char c; while((c = s[i])) s[i++] = c == a ? b : c; return s; } /* string char swap */
char *scat(char *dst, const char *src) { char *ptr = dst + slen(dst); while(*src) *ptr++ = *src++; *ptr = '\0'; return dst; } /* string cat */
int   ssin(char *s, char *ss) { int a = 0, b = 0; while(s[a]) { if(s[a] == ss[b]) { if(!ss[b + 1]) return a - b; b++; } else b = 0; a++; } return -1; } /* string substring index */
char *ccat(char *dst, char c) { int len = slen(dst); dst[len] = c; dst[len + 1] = '\0'; return dst; }

/* clang-format on */
int chatty9p = 1;
static int serving = 1;

static char Ebad[] = "something bad happened";
static char Enomem[] = "no memory";

enum { CTL = 1, SLOT, CART, REALM, UNIVERSE };

typedef struct Aux Aux;
struct Aux {
  int type;
  char* data;
  int count;
};

void fsread(Req* r) {
  Aux* a;
  vlong offset;
  long count;

  a = r->fid->file->aux;
  offset = r->ifcall.offset;
  count = r->ifcall.count;

  /*print("read %ld %lld\n", *count, offset); */
  if (offset >= a->count) {
    r->ofcall.count = 0;
    respond(r, nil);
    return;
  }

  if (offset + count >= a->count)
    count = a->count - offset;

  memmove(r->ofcall.data, a->data + offset, count);
  r->ofcall.count = count;
  respond(r, nil);
}

unsigned long long hash(char* str) {
  unsigned long long h;
  unsigned char* p;

  h = 0;
  for (p = (unsigned char*)str; *p != '\0'; p++)
    h = 37 * h + *p;
  return h; // or, h % ARRAY_SIZE;
}

void fswrite(Req* r) {
  void* v;
  Aux* a;
  vlong offset;
  long count;

  a = r->fid->file->aux;
  offset = r->ifcall.offset;
  count = r->ifcall.count;

  if (offset + count >= a->count) {
    v = realloc(a->data, offset + count);
    if (v == nil) {
      respond(r, Enomem);
      return;
    }
    a->data = v;
    a->count = offset + count;
    r->fid->file->dir.length = a->count;
  }
  memmove(a->data + offset, r->ifcall.data, count);
  r->ofcall.count = count;
  respond(r, nil);
}

void handlectl(Req* r) {
  char cmd[16];
  char* c = r->ifcall.data;
  int i;

  for (i = 0; i < r->ifcall.count; i++) {
    ccat(cmd, *c++);
  }

  unsigned long long const cmd_hashv = hash(cmd);

  switch (cmd_hashv) {
    case SHUTDOWN_HASHV:
      printf("what");
      break;
    default:
      break;
  }
  r->ofcall.count = r->ifcall.count;
  r->fid->file->dir.length = r->ifcall.count;
}

void xrxswrite(Req* r) {
  Aux* a = r->fid->file->aux;
  switch (a->type) {
    case CTL:
      handlectl(r);
      break;
    default:
      break;
  }
  respond(r, nil);
}

void fsopen(Req* r) { respond(r, nil); }

void wstat(Req* r) { respond(r, nil); }

void fsdestroyfile(File* f) {
  Aux* a = f->aux;
  if (a && a->data) {
    free(a->data);
    free(a);
  } else if (a) {
    free(a);
  }
}

String** listdir(char* path) {
  String** self = malloc(128 * sizeof(String*));
  DIR* dir;
  struct dirent* ent;
  int i = 0;
  char* c;
  if ((dir = opendir(path)) != NULL) {
    while ((ent = readdir(dir)) != NULL) {
      c = ent->d_name;
      if (scmp(c, ".") || scmp(c, "..")) {
        continue;
      }
      self[i] = s_new();

      while (*c) {
        s_putc(self[i], *c++);
      }
      s_terminate(self[i++]);
    }
    closedir(dir);
  }
  self[i] = nil;
  return self;
}

Srv fs = {
  .open = fsopen,
  .read = fsread,
  .write = xrxswrite,
  .create = fsopen,
  .wstat = wstat};

int threadmaybackground(void) { return 1; }

void threadmain(int argc, char* argv[]) {
  Tree* tree;
  char* mtpt = nil;
  char* usocket = nil;
  int i;
  String** cart;
  Aux* ctlfile = malloc(sizeof(Aux));
  ctlfile->type = CTL;
  ctlfile->data = malloc(256 * sizeof(char));
  ctlfile->count = 0;

  /* if -m PATH is supplied, mount on PATH */
  /* if -s NAME is supplied, create a socket for the namespace */
  /* otherwise, just use srv() (for wrapping with socat or inetd) */

  if (argc >= 3) {
    for (i = 0; i < argc; i++) {
      if (scmp(argv[i], "-m")) {
        mtpt = argv[++i];
        printf("serving on %s", mtpt);
      } else if (scmp(argv[i], "-s")) {
        usocket = argv[++i];
        printf("serving socket namespace %s", usocket);
      }
    }
  }

  fs.foreground = 1;
  fs.tree = alloctree(nil, nil, DMDIR | 0777, fsdestroyfile);
  tree = fs.tree;
  closefile(createfile(tree->root, "carts", nil, DMDIR | 0555, nil));
  closefile(createfile(tree->root, "ctl", nil, DMAPPEND | 0300, ctlfile));
  String** carts = listdir("carts/");
  cart = carts;
  while (*cart) {
    closefile(
      createfile(walkfile(tree->root, "carts"), (*cart)->base, nil, 0444, nil));
    cart++;
  }

  while (serving) {
    if (argc >= 3) {
      if (mtpt != nil && access(mtpt, AEXIST) < 0 && access(mtpt, AEXIST) < 0)
        sysfatal("mountpoint %s does not exist", mtpt);

      threadpostmountsrv(&fs, usocket, mtpt, MREPL | MCREATE);
      threadexits(0);
    } else {
      srv(&fs);
    }
  }
}