#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>

/* 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 char Ebad[] = "something bad happened";
static char Enomem[] = "no memory";
static char Euname[] = "username is already taken";

static Tree* tree;

typedef enum {
  LOGIN = 208176873,
  LOAD = 5626172,
  CREATE = 7083959236,
  PROTECT = 295480618573,
  ENTER = 195024746,
  LEAVE = 207662601,
  LOGOUT = 7702552890,
  SAVE = 5962355,
  RESET = 218931595,
  UNLOAD = 8325026851
} Command;

typedef enum { CTL = 1, USERS, CARTS, SLOT, DATA, REALMS, UNIVERSE } FileType;

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

Aux* create_aux(FileType t) {
  Aux* self = (Aux*)malloc(sizeof(Aux));
  self->type = t;
  self->data = nil;
  self->count = 0;

  return self;
}

typedef struct UserInfo UserInfo;
struct UserInfo {
  char name[32];
  uvlong password;
  char realm[32];
  char cart[32];
};

static UserInfo users_table[64];

uvlong hash(char* str) {
  uvlong h;
  uchar* p;

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

void xrxs_attach(Req* r) {
  /* As it is, once the user detaches, they will stay in the table
   * until the server restarts. We have to figure out some way
   * to detect a detach to remove them... You can't delay respond()
   * or the attach will never complete.
   */
  int i = 0;
  int l = 0;
  char* usr;
  char* username = r->ifcall.uname;
  usr = username;
  while (*usr) {
    l++;
    usr++;
  }
  for (i = 0; i < 64; i++) {
    usr = users_table[i].name;
    if (scmp(usr, username)) {
      respond(r, Euname);
      return;
    }
    if (*usr == 0) {
      scpy(username, usr, l + 1);
      break;
    }
  }
  respond(r, nil);
}

void login(char* uname, char* password) {
  int i;
  for (i = 0; i < 64; i++) {
    if (scmp(uname, users_table[i].name)) {
      users_table[i].password = hash(password);
    }
  }
}

int logout(char* uname) {
  int i;
  fprintf(stderr, uname);
  for (i = 0; i < 64; i++) {
    if (scmp(uname, users_table[i].name)) {
      *(users_table[i].name) = 0;
      users_table[i].password = 0;
      *(users_table[i].realm) = 0;
      return 1;
    }
  }
  return 0;
}

int load(char* cart) {
  /* 1. get file handle to cartridge file
   * 2. make cartridge file available in CART.data for this user
   * 3. add cartridge name to user's UserInfo
   * 4. if cartridge data dir is not empty, walk it
   * 5. for each file in data dir, create corresponding
   *    data file in DATA/ for this user, grab a file handle, and make
   *    the data available in DATA.data
   */
  return 1;
}

int rcreate(char* realm) { // create is taken in the libc header!
  /* 1. split input by space -- if 2+ elements, second element
   *    is the max number of members (default 4)
   * 2. check if realm exists; return 0 if it does
   * 3. create real files in the realms directory and fill as
   *    appropriate
   */
  return 1;
}

int protect(char* password) {
  /* 1. if current realm has a password already, return 0;
   * 2. otherwise, hash the password and put it after the
   *    member limit in the realm file
   */
  return 1;
}

int enter(char* realm) {
  /* 1. get password for realm; if none, skip to 3
   * 2. check password for current user against it;
   *    return 0 if different
   * 3. if member limit already met, return 0
   * 4. otherwise, insert username in the realm
   *    and the realm name in the user's UserInfo
   */
  return 1;
}

int leave(char* uname) {
  /* 1. if not in a realm, return 0;
   * 2. else remove self from realm file
   *    and remove realm from user's UserInfo
   */
  return 1;
}

int save(char* uname) {
  /* 1. flush this user's universe to the realm;
   * maybe this is not needed
   */
  return 1;
}

int reset(char* uname) {
  /* 1. save
   * 2. leave
   * 3. clear this user's password
   * 4. the client should now be able to restart execution
   *    of the cartridge safely
   */
  return 1;
}

int unload(char* uname) {
  /* 1. reset
   * 2. clear cartridge data from CART->data for this user
   * 3. destroy all files in DATA/ for this user
   * 4. remove cartridge from UserInfo for thi user
   * 5. the client should now be able to unload
   *    the cartridge from memory safely and restart
   *    the 'firmware' ROM execution
   */
  return 1;
}

void write_ctl(Req* r) {
  char cmd[16] = {0};
  char* c = r->ifcall.data;
  int i;

  for (i = 0; i < r->ifcall.count && *c != ' ' && *c != '\n'; i++) {
    ccat(cmd, *c++);
  }
  fprintf(stderr, cmd);
  uvlong const cmd_hashv = hash(cmd);
  switch (cmd_hashv) {
    case LOGIN:
      login(r->fid->uid, c);
      break;
    case LOAD:
      // load(c);
      break;
    case CREATE:
      // rcreate(c);
      break;
    case PROTECT:
      // protect(c);
      break;
    case ENTER:
      // enter(c);
      break;
    case LEAVE:
      // leave(r->fid->uid);
      break;
    case LOGOUT:
      logout(r->fid->uid);
      break;
    case SAVE:
      // save(r->fid->uid);
      break;
    case RESET:
      // reset(r->fid->uid);
      break;
    case UNLOAD:
      // unload(r->fid->uid);
      break;
  }
  r->ofcall.count = r->ifcall.count;
  r->fid->file->dir.length = r->ifcall.count;
  respond(r, nil);
}

void xrxs_write(Req* r) {
  Aux* a = r->fid->file->aux;
  switch (a->type) {
    case CTL:
      write_ctl(r);
      break;
    case UNIVERSE:
      // write_universe(r);
      break;
    default:
      respond(r, nil);
      break;
  }
}

void read_users(Req* r) {
  char buf[2113] = {0};
  int i;
  for (i = 0; i < 64; i++) {
    if (scmp(users_table[i].name, r->fid->uid)) {
      scat(buf, users_table[i].name);
      ccat(buf, '\n');
      break;
    }
  }
  for (i = 0; i < 64; i++) {
    if (
      scmp(users_table[i].name, "\0") ||
      scmp(users_table[i].name, r->fid->uid)) {
      continue;
    }
    scat(buf, users_table[i].name);
    ccat(buf, '\n');
  }
  ccat(buf, 0);
  readstr(r, buf);
  respond(r, nil);
}

void xrxs_read(Req* r) {
  Aux* a = r->fid->file->aux;
  switch (a->type) {
    case USERS:
      read_users(r);
      break;
    case CARTS:
      // read_carts(r);
      break;
    case SLOT:
      // read_slot(r);
      break;
    case DATA:
      // read_data(r);
      break;
    case REALMS:
      // read_realms(r);
      break;
    case UNIVERSE:
      // read_universe(r);
      break;
    default:
      respond(r, nil);
      break;
  }
}

void fs_destroy_file(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 = {.attach = xrxs_attach, .read = xrxs_read, .write = xrxs_write};

int threadmaybackground(void) { return 1; }

void threadmain(int argc, char* argv[]) {
  char* mtpt = nil;
  char* usocket = nil;
  int i;
  String** cart;

  /* if -h CMD is given, print the hash value of CMD */
  if (argc == 3 && scmp(argv[1], "-h")) {
    printf("%llu\n", hash(argv[2]));
    return;
  }

  /* 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, fs_destroy_file);
  tree = fs.tree;

  closefile(
    createfile(tree->root, "ctl", nil, DMAPPEND | 0300, create_aux(CTL)));
  closefile(createfile(tree->root, "carts", nil, 0400, create_aux(CARTS)));
  closefile(createfile(tree->root, "users", nil, 0400, create_aux(USERS)));
  closefile(createfile(tree->root, "slot", nil, 0400, create_aux(SLOT)));
  closefile(createfile(tree->root, "data", nil, DMDIR | 0500, nil));
  closefile(createfile(tree->root, "realms", nil, 0400, create_aux(REALMS)));
  closefile(
    createfile(tree->root, "universe", nil, 0600, create_aux(UNIVERSE)));
  /*String** carts = listdir("carts/");
  cart = carts;

  while (*cart) {
    // just concatenate the carts into a multiline string, and put it in
  CARTS.data
  }*/

  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);
  }
}