#include "forth_internal.h"

static enum fh_error w_colon(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  ENSURE_STATE(FH_STATE_INTERPRET);

  char *wordname = NULL;
  size_t namelen = 0;
  fh_input_consume_spaces(fh);
  TRY(fh_input_read_word(fh, &wordname, &namelen));
  LOG("Name: %.*s", namelen, wordname);

  fh_setstate(fh, FH_STATE_COMPILE, 0);

  uint32_t ptr;
  TRY(fh_heap_reserve(fh, DICTWORD_SIZE, &ptr));

  struct fh_word_s *new_word = fh_word_at(fh, ptr);
  if (!new_word) return FH_ERR_INTERNAL;
  new_word->previous = fh->dict_last;
  new_word->param = fh->here;
  new_word->handler = w_user_word;
  strncpy(new_word->name, wordname, namelen);
  new_word->name[namelen] = 0;
  new_word->flags = WORDFLAG_WORD;

  fh->dict_last = ptr;

  return FH_OK;
}

static enum fh_error w_forget(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  ENSURE_STATE(FH_STATE_INTERPRET);

  char *wordname = NULL;
  size_t namelen = 0;
  fh_input_consume_spaces(fh);
  TRY(fh_input_read_word(fh, &wordname, &namelen));
  LOG("Name to forget: %.*s", namelen, wordname);

  uint32_t addr;
  TRY(fh_find_word(fh, wordname, namelen, &addr));

  struct fh_word_s *removedword = fh_word_at(fh, addr);
  if (!removedword) return FH_ERR_INTERNAL;
  fh->dict_last = removedword->previous;
  return FH_OK;
}

static enum fh_error w_postpone(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  ENSURE_STATE(FH_STATE_COMPILE);

  char *wordname;
  size_t namelen = 0;
  fh_input_consume_spaces(fh);
  TRY(fh_input_read_word(fh, &wordname, &namelen));
  TRY(fh_postpone_word(fh, wordname, namelen));

  return FH_OK;
}

static enum fh_error rt_read_value(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  enum fh_error rv;
  TRY(ds_push(fh, w->param));
  return FH_OK;
}

static enum fh_error rt_read_varaddr(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  enum fh_error rv;
  uint32_t addr = (void *) &w->param - (void *) &fh->heap[0]; // this is ugly
  TRY(ds_push(fh, addr));
  return FH_OK;
}

static enum fh_error wp_variable(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;

  bool is_value = w->param == 1;
  bool is_const = w->param == 2;

  if (is_const && fh->state == FH_STATE_COMPILE) {
    uint32_t wordaddr = (void *)w - (void *)&fh->heap[0]; // this is ugly
    TRY(fh_put_instr(fh, FH_INSTR_WORD, wordaddr));
    return FH_OK;
  }

  ENSURE_STATE(FH_STATE_INTERPRET);

  char *wordname;
  size_t namelen = 0;
  fh_input_consume_spaces(fh);
  TRY(fh_input_read_word(fh, &wordname, &namelen));

  uint32_t ptr;
  uint32_t value = 0;

  if (is_value || is_const) {
    TRY(ds_pop(fh, &value));
  }

  TRY(fh_heap_reserve(fh, DICTWORD_SIZE, &ptr));

  struct fh_word_s *new_word = fh_word_at(fh, ptr);
  if (!new_word) return FH_ERR_INTERNAL;
  new_word->previous = fh->dict_last;
  new_word->param = value;
  new_word->handler = (is_value || is_const) ? rt_read_value : rt_read_varaddr;
  strncpy(new_word->name, wordname, namelen);
  new_word->name[namelen] = 0;
  new_word->flags = (is_const ? WORDFLAG_CONSTANT : WORDFLAG_VARIABLE) | WORDFLAG_BUILTIN;

  if (is_const) {
    LOG("Create CONSTANT %s = %d (0x%08x)", new_word->name, value, value);
  } else if (is_value) {
    LOG("Create VALUE %s = %d (0x%08x)", new_word->name, value, value);
  } else {
    LOG("Create VARIABLE %s at 0x%08x", new_word->name, ptr); // param field is the first
  }

  fh->dict_last = ptr;

  return FH_OK;
}

static enum fh_error w_to(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  if (fh->state == FH_STATE_INTERPRET) {
    uint32_t value;
    TRY(ds_pop(fh, &value));

    char *wordname;
    size_t namelen = 0;
    uint32_t waddr;
    fh_input_consume_spaces(fh);
    TRY(fh_input_read_word(fh, &wordname, &namelen));
    TRY(fh_find_word(fh, wordname, namelen, &waddr));

    struct fh_word_s *ww = fh_word_at(fh, waddr);
    if (!ww) return FH_ERR_INTERNAL;

    if (ww->flags & WORDFLAG_WORD) {
      LOGE("Cannot assign to dictionary word param field!");
      return FH_ERR_NOT_APPLICABLE;
    }

    if (ww->flags & WORDFLAG_CONSTANT) {
      LOGE("Cannot assign to constant!");
      return FH_ERR_NOT_APPLICABLE;
    }

    ww->param = value;
  } else if (fh->state == FH_STATE_COMPILE) {
    // immediate
    char *wordname;
    size_t namelen = 0;
    uint32_t waddr;
    fh_input_consume_spaces(fh);
    TRY(fh_input_read_word(fh, &wordname, &namelen));
    TRY(fh_find_word(fh, wordname, namelen, &waddr));

    TRY(fh_put_instr(fh, FH_INSTR_TO, waddr));
  }

  return FH_OK;
}

static enum fh_error w_leftbracket(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  ENSURE_STATE(FH_STATE_COMPILE);
  fh_setstate(fh, FH_STATE_INTERPRET, 0);
  return FH_OK;
}

static enum fh_error w_rightbracket(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  ENSURE_STATE(FH_STATE_INTERPRET);
  fh_setstate(fh, FH_STATE_COMPILE, 0);
  return FH_OK;
}

static enum fh_error w_source(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  TRY(ds_push(fh, INPUTBUF_ADDR));
  TRY(ds_push(fh, fh->inputlen));
//  TRY(ds_push(fh, INPUTBUF_ADDR + fh->inputptr));
//  TRY(ds_push(fh, fh->inputlen - fh->inputptr));
  return FH_OK;
}

static enum fh_error w_literal(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  ENSURE_STATE(FH_STATE_COMPILE);

  uint32_t val;
  TRY(ds_pop(fh, &val));
  TRY(fh_put_instr(fh, FH_INSTR_NUMBER, val));

  return FH_OK;
}

static enum fh_error w_semicolon(struct fh_thread_s *fh, const struct fh_word_s *w0)
{
  (void) w0;
  enum fh_error rv;

  ENSURE_STATE(FH_STATE_COMPILE);
  TRY(fh_put_instr(fh, FH_INSTR_ENDWORD, 0));

  /* Return to interpret state */
  fh_setstate(fh, FH_STATE_INTERPRET, 0);

  // XXX if there was another definition previously and it was used in some other compiled function,
  //  that old implementation will still be called.

  return FH_OK;
}

static enum fh_error w_immediate(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;

  if (fh->dict_last == 0) {
    LOGE("Dict is empty, cannot modify previous word!");
    return FH_ERR_INVALID_STATE;
  }

  struct fh_word_s *word = fh_word_at(fh, fh->dict_last);
  if (!word) return FH_ERR_INTERNAL;
  word->flags |= WORDFLAG_IMMEDIATE;

  return FH_OK;
}

static enum fh_error w_backslash(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  fh_setsubstate(fh, FH_SUBSTATE_LINE_COMMENT);
  return FH_OK;
}

static enum fh_error w_paren(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  fh_setsubstate(fh, FH_SUBSTATE_PAREN_COMMENT);
  return FH_OK;
}

static enum fh_error wp_char(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  bool bracketed = w->param;
  if (bracketed) ENSURE_STATE(FH_STATE_COMPILE);

  char *wordname = NULL;
  size_t namelen = 0;
  fh_input_consume_spaces(fh);
  TRY(fh_input_read_word(fh, &wordname, &namelen));

  char c = (char) *wordname;
  if (bracketed) {
    TRY(fh_put_instr(fh, FH_INSTR_NUMBER, c));
  } else {
    TRY(ds_push(fh, c));
  }
  return FH_OK;
}

static enum fh_error w_depth(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  TRY(ds_push(fh, fh->data_stack_top));
  return FH_OK;
}

static enum fh_error w_unused(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  TRY(ds_push(fh, HEAP_SIZE - fh->here));
  return FH_OK;
}

static enum fh_error w_to_in(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  TRY(ds_push(fh, MAGICADDR_INPTR));
  return FH_OK;
}

static bool chartest_equals_or_end(char c, void *param)
{
  char cc = (char) *(uint32_t *) param;
  return c == cc || c == 0;
}


static enum fh_error w_word(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t ch;
  TRY(ds_pop(fh, &ch));
  if (ch > 0xFF) {
    LOGE("Char out of ASCII bounds!");
    return FH_ERR_NOT_APPLICABLE;
  }

  fh_input_consume_matching(fh, chartest_equals_or_end, &ch);

  char *out;
  size_t len;
  fh_input_read_delimited(fh, &out, &len, chartest_equals_or_end, &ch);
  if (len >= WORDBUF_SIZE) {
    LOGE("WORD parsed string too long");
    return FH_ERR_NAME_TOO_LONG;
  }

  fh_store_char(fh, WORDBUF_ADDR, (char) len);
  fh_heap_copyptr(fh, WORDBUF_ADDR + 1, out, len);

  TRY(ds_push(fh, WORDBUF_ADDR));
  return FH_OK;
}

static enum fh_error w_count(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t caddr;
  TRY(ds_pop(fh, &caddr));

  uint8_t len;
  TRY(fh_fetch_char(fh, caddr, (char *) &len));
  TRY(ds_push(fh, caddr + 1));
  TRY(ds_push(fh, len));
  return FH_OK;
}

static enum fh_error w_create(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  ENSURE_STATE(FH_STATE_INTERPRET);

  char *wordname;
  size_t namelen = 0;
  fh_input_consume_spaces(fh);
  TRY(fh_input_read_word(fh, &wordname, &namelen));

  uint32_t ptr;

  TRY(fh_heap_reserve(fh, DICTWORD_SIZE, &ptr));

  struct fh_word_s *new_word = fh_word_at(fh, ptr);
  if (!new_word) return FH_ERR_INTERNAL;
  new_word->previous = fh->dict_last;
  new_word->param = fh->here;
  new_word->handler = rt_read_value;
  strncpy(new_word->name, wordname, namelen);
  new_word->name[namelen] = 0;
  new_word->flags = WORDFLAG_BUILTIN | WORDFLAG_CREATED;

  fh->dict_last = ptr;

  return FH_OK;
}

static enum fh_error w_find(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  ENSURE_STATE(FH_STATE_INTERPRET);

  uint32_t caddr;
  TRY(ds_pop(fh, &caddr));
  uint8_t len;
  TRY(fh_fetch_char(fh, caddr, (char *) &len));

  uint32_t addr;

  if (FH_OK != fh_find_word(fh, fh_str_at(fh, caddr + 1), len, &addr)) {
    /* not found */
    TRY(ds_push(fh, caddr));
    TRY(ds_push(fh, 0));
    return FH_OK;
  }

  struct fh_word_s *word = fh_word_at(fh, addr);
  if (!word) return FH_ERR_INTERNAL;

  TRY(ds_push(fh, addr));
  TRY(ds_push(fh, (word->flags & WORDFLAG_IMMEDIATE) ? 1 : -1));

  return FH_OK;
}

static enum fh_error wp_tick(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  bool bracketed = w->param;
  if (bracketed) ENSURE_STATE(FH_STATE_COMPILE);

  char *wordname;
  size_t namelen = 0;
  fh_input_consume_spaces(fh);
  TRY(fh_input_read_word(fh, &wordname, &namelen));

  uint32_t addr;
  if (FH_OK != fh_find_word(fh, wordname, namelen, &addr)) {
    LOGE("' %.*s word not found!", (int) namelen, wordname);
    return FH_ERR_UNKNOWN_WORD;
  }

  if (bracketed) {
    TRY(fh_put_instr(fh, FH_INSTR_NUMBER, addr));
  } else {
    TRY(ds_push(fh, addr));
  }
  return FH_OK;
}

static enum fh_error w_execute(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;

  uint32_t addr;
  TRY(ds_pop(fh, &addr));

  if (addr != WORDALIGNED(addr)) {
    LOGE("Invalid execution token, address must be aligned!");
    return FH_ERR_ILLEGAL_FETCH;
  }

  struct fh_word_s *word = fh_word_at(fh, addr);
  if (!word) {
    LOGE("Execute with bad addr");
    return FH_ERR_NOT_APPLICABLE;
  }
  if (!word->handler) {
    LOGE("Execute word with no handler");
    return FH_ERR_NOT_APPLICABLE;
  }
  TRY(word->handler(fh, word));
  return FH_OK;
}

static enum fh_error w_env_query(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;

  uint32_t len;
  TRY(ds_pop(fh, &len));
  uint32_t addr;
  TRY(ds_pop(fh, &addr));
  const char *str = fh_str_at(fh, addr);
  if (!str) {
    LOGE("Bad string addr for env query!");
    return FH_ERR_NOT_APPLICABLE;
  }

  LOG("Test environment \"%.*s\"", len, str);

  if (EQ(str, "/COUNTED-STRING", len)) {
    TRY(ds_push(fh, 255));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "/HOLD", len)) {
    TRY(ds_push(fh, WORDBUF_SIZE));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "/PAD", len)) {
    TRY(ds_push(fh, MIN_PAD_SIZE));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "ADDRESS-UNIT-BITS", len)) {
    TRY(ds_push(fh, 8));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "FLOORED", len)) {
    TRY(ds_push(fh, TOBOOL(1))); // FIXME is it?
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "MAX-CHAR", len)) {
    TRY(ds_push(fh, 255));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "MAX-D", len)) {
    // TODO update when double arith is properly implemented
    TRY(ds_push(fh, 0));
  }
  else if (EQ(str, "MAX-UD", len)) {
    // TODO update when double arith is properly implemented
    TRY(ds_push(fh, 0));
  }
  else if (EQ(str, "MAX-N", len)) {
    TRY(ds_push(fh, 0x7FFFFFFFULL));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "MAX-U", len)) {
    TRY(ds_push(fh, 0xFFFFFFFFULL));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "RETURN-STACK-CELLS", len)) {
    TRY(ds_push(fh, RETURN_STACK_DEPTH));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "STACK-CELLS", len)) {
    TRY(ds_push(fh, DATA_STACK_DEPTH));
    TRY(ds_push(fh, 1));
  }
  else if (EQ(str, "CORE", len)) {
    TRY(ds_push(fh, TOBOOL(1)));
    TRY(ds_push(fh, 1));
  }
  else {
    TRY(ds_push(fh, 0));
  }

  return FH_OK;
}

const struct name_and_handler fh_builtins_meta[] = {
    {"depth",        w_depth,        0, 0},
    {"unused",       w_unused,       0, 0},
    {">in",          w_to_in,        0, 0},
    {":",            w_colon,        0, 0},
    {";",            w_semicolon,    1, 0},
    {"forget",       w_forget,       1, 0},
    {"\\",           w_backslash,    1, 0}, // line comment
    {"(",            w_paren,        1, 0}, // enclosed comment
    {"immediate",    w_immediate,    0, 0},
    {"postpone",     w_postpone,     1, 0},
    {"[",            w_leftbracket,  1, 0},
    {"]",            w_rightbracket, 1, 0},
    {"source",       w_source,       0, 0},
    {"literal",      w_literal,      1, 0},
    {"char",         wp_char,        0, 0},
    {"[char]",       wp_char,        1, 1},
    {"to",           w_to,           1, 0},
    {"variable",     wp_variable,    1, 0},
    {"value",        wp_variable,    1, 1},
    {"constant",     wp_variable,    1, 2},
    {"word",         w_word,         0, 0},
    {"count",        w_count,        0, 0},
    {"create",       w_create,       0, 0},
    {"find",         w_find,         0, 0},
    {"'",            wp_tick,        1, 0},
    {"[']",          wp_tick,        1, 1},
    {"execute",      w_execute,      0, 0},
    {"environment?", w_env_query,    0, 0},
    { /* end marker */ }
};