#include <assert.h>
#include <stdbool.h>
#include <string.h>

#include "nvim/api/keysets_defs.h"
#include "nvim/api/options.h"
#include "nvim/api/private/defs.h"
#include "nvim/api/private/dispatch.h"
#include "nvim/api/private/helpers.h"
#include "nvim/api/private/validate.h"
#include "nvim/autocmd.h"
#include "nvim/autocmd_defs.h"
#include "nvim/buffer.h"
#include "nvim/buffer_defs.h"
#include "nvim/globals.h"
#include "nvim/memline.h"
#include "nvim/memory.h"
#include "nvim/memory_defs.h"
#include "nvim/option.h"
#include "nvim/types_defs.h"
#include "nvim/vim_defs.h"
#include "nvim/window.h"

#ifdef INCLUDE_GENERATED_DECLARATIONS
# include "api/options.c.generated.h"
#endif

static int validate_option_value_args(Dict(option) *opts, char *name, OptIndex *opt_idxp,
                                      int *opt_flags, OptScope *scope, void **from, char **filetype,
                                      Error *err)
{
#define HAS_KEY_X(d, v) HAS_KEY(d, option, v)
  if (HAS_KEY_X(opts, scope)) {
    if (!strcmp(opts->scope.data, "local")) {
      *opt_flags = OPT_LOCAL;
    } else if (!strcmp(opts->scope.data, "global")) {
      *opt_flags = OPT_GLOBAL;
    } else {
      VALIDATE_EXP(false, "scope", "'local' or 'global'", NULL, {
        return FAIL;
      });
    }
  }

  *scope = kOptScopeGlobal;

  if (filetype != NULL && HAS_KEY_X(opts, filetype)) {
    *filetype = opts->filetype.data;
  }

  if (HAS_KEY_X(opts, win)) {
    *scope = kOptScopeWin;
    *from = find_window_by_handle(opts->win, err);
    if (ERROR_SET(err)) {
      return FAIL;
    }
  }

  if (HAS_KEY_X(opts, buf)) {
    VALIDATE(!(HAS_KEY_X(opts, scope) && *opt_flags == OPT_GLOBAL), "%s",
             "cannot use both global 'scope' and 'buf'", {
      return FAIL;
    });
    *opt_flags = OPT_LOCAL;
    *scope = kOptScopeBuf;
    *from = find_buffer_by_handle(opts->buf, err);
    if (ERROR_SET(err)) {
      return FAIL;
    }
  }

  VALIDATE((!HAS_KEY_X(opts, filetype)
            || !(HAS_KEY_X(opts, buf) || HAS_KEY_X(opts, scope) || HAS_KEY_X(opts, win))),
           "%s", "cannot use 'filetype' with 'scope', 'buf' or 'win'", {
    return FAIL;
  });

  VALIDATE((!HAS_KEY_X(opts, win) || !HAS_KEY_X(opts, buf)),
           "%s", "cannot use both 'buf' and 'win'", {
    return FAIL;
  });

  *opt_idxp = find_option(name);
  if (*opt_idxp == kOptInvalid) {
    // unknown option
    api_set_error(err, kErrorTypeValidation, "Unknown option '%s'", name);
  } else if (*scope == kOptScopeBuf || *scope == kOptScopeWin) {
    // if 'buf' or 'win' is passed, make sure the option supports it
    if (!option_has_scope(*opt_idxp, *scope)) {
      char *tgt = *scope == kOptScopeBuf ? "buf" : "win";
      char *global = option_has_scope(*opt_idxp, kOptScopeGlobal) ? "global " : "";
      char *req = option_has_scope(*opt_idxp, kOptScopeBuf)
                  ? "buffer-local "
                  : (option_has_scope(*opt_idxp, kOptScopeWin) ? "window-local " : "");

      api_set_error(err, kErrorTypeValidation, "'%s' cannot be passed for %s%soption '%s'",
                    tgt, global, req, name);
    }
  }

  return ERROR_SET(err) ? FAIL : OK;
#undef HAS_KEY_X
}

/// Create a dummy buffer and run the FileType autocmd on it.
static buf_T *do_ft_buf(const char *filetype, aco_save_T *aco, bool *aco_used, Error *err)
  FUNC_ATTR_NONNULL_ARG(2, 3, 4)
{
  *aco_used = false;
  if (filetype == NULL) {
    return NULL;
  }

  // Allocate a buffer without putting it in the buffer list.
  buf_T *ftbuf = buflist_new(NULL, NULL, 1, BLN_DUMMY);
  if (ftbuf == NULL) {
    api_set_error(err, kErrorTypeException, "Could not create internal buffer");
    return NULL;
  }

  // Open a memline for use by autocommands.
  if (ml_open(ftbuf) == FAIL) {
    api_set_error(err, kErrorTypeException, "Could not load internal buffer");
    return ftbuf;
  }

  bufref_T bufref;
  set_bufref(&bufref, ftbuf);

  // Set curwin/curbuf to buf and save a few things.
  aucmd_prepbuf(aco, ftbuf);
  *aco_used = true;

  set_option_direct(kOptBufhidden, STATIC_CSTR_AS_OPTVAL("hide"), OPT_LOCAL, SID_NONE);
  set_option_direct(kOptBuftype, STATIC_CSTR_AS_OPTVAL("nofile"), OPT_LOCAL, SID_NONE);
  assert(ftbuf->b_ml.ml_mfp->mf_fd < 0);  // ml_open() should not have opened swapfile already
  ftbuf->b_p_swf = false;
  ftbuf->b_p_ml = false;
  ftbuf->b_p_ft = xstrdup(filetype);

  TRY_WRAP(err, {
    do_filetype_autocmd(ftbuf, false);
  });

  if (!bufref_valid(&bufref)) {
    if (!ERROR_SET(err)) {
      api_set_error(err, kErrorTypeException, "Internal buffer was deleted");
    }
    return NULL;
  }

  return ftbuf;
}

static void wipe_ft_buf(buf_T *buf)
  FUNC_ATTR_NONNULL_ALL
{
  block_autocmds();

  bufref_T bufref;
  set_bufref(&bufref, buf);

  close_windows(buf, false);
  // Autocommands are blocked, but 'bufhidden' may have wiped it already.
  // Also can't wipe if the buffer is somehow still in a window or current.
  if (bufref_valid(&bufref) && buf != curbuf && buf->b_nwindows == 0) {
    wipe_buffer(buf, false);
  }
  if (bufref_valid(&bufref)) {
    buf->b_flags &= ~BF_DUMMY;  // Couldn't wipe; keep it instead.
  }

  unblock_autocmds();
}

/// Gets the value of an option. The behavior of this function matches that of
/// |:set|: the local value of an option is returned if it exists; otherwise,
/// the global value is returned. Local values always correspond to the current
/// buffer or window, unless "buf" or "win" is set in {opts}.
///
/// @param name      Option name
/// @param opts      Optional parameters
///                  - scope: One of "global" or "local". Analogous to
///                  |:setglobal| and |:setlocal|, respectively.
///                  - win: |window-ID|. Used for getting window local options.
///                  - buf: Buffer number. Used for getting buffer local options.
///                         Implies {scope} is "local".
///                  - filetype: |filetype|. Used to get the default option for a
///                    specific filetype. Cannot be used with any other option.
///                    Note: this will trigger |ftplugin| and all |FileType|
///                    autocommands for the corresponding filetype.
/// @param[out] err  Error details, if any
/// @return          Option value
Object nvim_get_option_value(String name, Dict(option) *opts, Error *err)
  FUNC_API_SINCE(9) FUNC_API_RET_ALLOC
{
  OptIndex opt_idx = 0;
  int opt_flags = 0;
  OptScope scope = kOptScopeGlobal;
  void *from = NULL;
  char *filetype = NULL;

  if (!validate_option_value_args(opts, name.data, &opt_idx, &opt_flags, &scope, &from,
                                  &filetype, err)) {
    return (Object)OBJECT_INIT;
  }

  aco_save_T aco;
  bool aco_used;

  buf_T *ftbuf = do_ft_buf(filetype, &aco, &aco_used, err);
  if (ERROR_SET(err)) {
    if (aco_used) {
      // restore curwin/curbuf and a few other things
      aucmd_restbuf(&aco);
    }
    if (ftbuf != NULL) {
      wipe_ft_buf(ftbuf);
    }
    return (Object)OBJECT_INIT;
  }

  if (ftbuf != NULL) {
    assert(!from);
    from = ftbuf;
  }

  OptVal value = get_option_value_for(opt_idx, opt_flags, scope, from, err);

  if (ftbuf != NULL) {
    if (aco_used) {
      // restore curwin/curbuf and a few other things
      aucmd_restbuf(&aco);
    }
    wipe_ft_buf(ftbuf);
  }

  if (ERROR_SET(err)) {
    goto err;
  }

  VALIDATE_S(value.type != kOptValTypeNil, "option", name.data, {
    goto err;
  });

  return optval_as_object(value);
err:
  optval_free(value);
  return (Object)OBJECT_INIT;
}

/// Sets the value of an option. The behavior of this function matches that of
/// |:set|: for global-local options, both the global and local value are set
/// unless otherwise specified with {scope}.
///
/// Note the options {win} and {buf} cannot be used together.
///
/// @param name      Option name
/// @param value     New option value
/// @param opts      Optional parameters
///                  - scope: One of "global" or "local". Analogous to
///                  |:setglobal| and |:setlocal|, respectively.
///                  - win: |window-ID|. Used for setting window local option.
///                  - buf: Buffer number. Used for setting buffer local option.
/// @param[out] err  Error details, if any
void nvim_set_option_value(uint64_t channel_id, String name, Object value, Dict(option) *opts,
                           Error *err)
  FUNC_API_SINCE(9)
{
  OptIndex opt_idx = 0;
  int opt_flags = 0;
  OptScope scope = kOptScopeGlobal;
  void *to = NULL;
  if (!validate_option_value_args(opts, name.data, &opt_idx, &opt_flags, &scope, &to, NULL,
                                  err)) {
    return;
  }

  // If:
  // - window id is provided
  // - scope is not provided
  // - option is global or local to window (global-local)
  //
  // Then force scope to local since we don't want to change the global option
  if (scope == kOptScopeWin && opt_flags == 0) {
    if (option_has_scope(opt_idx, kOptScopeGlobal)) {
      opt_flags = OPT_LOCAL;
    }
  }

  bool error = false;
  OptVal optval = object_as_optval(value, &error);

  // Handle invalid option value type.
  // Don't use `name` in the error message here, because `name` can be any String.
  // No need to check if value type actually matches the types for the option, as set_option_value()
  // already handles that.
  VALIDATE_EXP(!error, "value", "valid option type", api_typename(value.type), {
    return;
  });

  WITH_SCRIPT_CONTEXT(channel_id, {
    set_option_value_for(name.data, opt_idx, optval, opt_flags, scope, to, err);
  });
}

/// Gets the option information for all options.
///
/// The dict has the full option names as keys and option metadata dicts as detailed at
/// |nvim_get_option_info2()|.
///
/// @see |nvim_get_commands()|
///
/// @return dict of all options
Dict nvim_get_all_options_info(Arena *arena, Error *err)
  FUNC_API_SINCE(7)
{
  return get_all_vimoptions(arena);
}

/// Gets the option information for one option from arbitrary buffer or window
///
/// Resulting dict has keys:
/// - name: Name of the option (like 'filetype')
/// - shortname: Shortened name of the option (like 'ft')
/// - type: type of option ("string", "number" or "boolean")
/// - default: The default value for the option
/// - was_set: Whether the option was set.
///
/// - last_set_sid: Last set script id (if any)
/// - last_set_linenr: line number where option was set
/// - last_set_chan: Channel where option was set (0 for local)
///
/// - scope: one of "global", "win", or "buf"
/// - global_local: whether win or buf option has a global value
///
/// - commalist: List of comma separated values
/// - flaglist: List of single char flags
///
/// When {scope} is not provided, the last set information applies to the local
/// value in the current buffer or window if it is available, otherwise the
/// global value information is returned. This behavior can be disabled by
/// explicitly specifying {scope} in the {opts} table.
///
/// @param name      Option name
/// @param opts      Optional parameters
///                  - scope: One of "global" or "local". Analogous to
///                  |:setglobal| and |:setlocal|, respectively.
///                  - win: |window-ID|. Used for getting window local options.
///                  - buf: Buffer number. Used for getting buffer local options.
///                         Implies {scope} is "local".
/// @param[out] err Error details, if any
/// @return         Option Information
Dict nvim_get_option_info2(String name, Dict(option) *opts, Arena *arena, Error *err)
  FUNC_API_SINCE(11)
{
  OptIndex opt_idx = 0;
  int opt_flags = 0;
  OptScope scope = kOptScopeGlobal;
  void *from = NULL;
  if (!validate_option_value_args(opts, name.data, &opt_idx, &opt_flags, &scope, &from, NULL,
                                  err)) {
    return (Dict)ARRAY_DICT_INIT;
  }

  buf_T *buf = (scope == kOptScopeBuf) ? (buf_T *)from : curbuf;
  win_T *win = (scope == kOptScopeWin) ? (win_T *)from : curwin;

  return get_vimoption(name, opt_flags, buf, win, arena, err);
}
