// Copyright (c) 2012, 2017 Peter Ohler. All rights reserved.
// Licensed under the MIT License. See LICENSE file in the project root for license details.

#include "dump.h"
#include "encode.h"
#include "mem.h"
#include "oj.h"
#include "parse.h"

extern const char oj_json_class[];

VALUE oj_array_nl_sym;
VALUE oj_ascii_only_sym;
VALUE oj_json_generator_error_class;
VALUE oj_json_parser_error_class;
VALUE oj_max_nesting_sym;
VALUE oj_object_nl_sym;
VALUE oj_space_before_sym;
VALUE oj_space_sym;

static VALUE state_class = Qundef;

// mimic JSON documentation

/* Document-module: JSON::Ext
 *
 * The Ext module is a placeholder in the mimic JSON module used for
 * compatibility only.
 */
/* Document-class: JSON::Ext::Parser
 *
 * The JSON::Ext::Parser is a placeholder in the mimic JSON module used for
 * compatibility only.
 */
/* Document-class: JSON::Ext::Generator
 *
 * The JSON::Ext::Generator is a placeholder in the mimic JSON module used for
 * compatibility only.
 */

/* Document-method: parser=
 * call-seq: parser=(parser)
 *
 * Does nothing other than provide compatibility.
 * - *parser* [_Object_] ignored
 */
/* Document-method: generator=
 * call-seq: generator=(generator)
 *
 * Does nothing other than provide compatibility.
 * - *generator* [_Object_] ignored
 */

VALUE
oj_get_json_err_class(const char *err_classname) {
    volatile VALUE json_module;
    volatile VALUE clas;
    volatile VALUE json_error_class;

    if (rb_const_defined_at(rb_cObject, rb_intern("JSON"))) {
        json_module = rb_const_get_at(rb_cObject, rb_intern("JSON"));
    } else {
        json_module = rb_define_module("JSON");
    }
    if (rb_const_defined_at(json_module, rb_intern("JSONError"))) {
        json_error_class = rb_const_get(json_module, rb_intern("JSONError"));
    } else {
        json_error_class = rb_define_class_under(json_module, "JSONError", rb_eStandardError);
    }
    if (0 == strcmp(err_classname, "JSONError")) {
        clas = json_error_class;
    } else {
        if (rb_const_defined_at(json_module, rb_intern(err_classname))) {
            clas = rb_const_get(json_module, rb_intern(err_classname));
        } else {
            clas = rb_define_class_under(json_module, err_classname, json_error_class);
        }
    }
    return clas;
}

void oj_parse_mimic_dump_options(VALUE ropts, Options copts) {
    VALUE  v;
    size_t len;

    if (T_HASH != rb_type(ropts)) {
        if (rb_respond_to(ropts, oj_to_hash_id)) {
            ropts = rb_funcall(ropts, oj_to_hash_id, 0);
        } else if (rb_respond_to(ropts, oj_to_h_id)) {
            ropts = rb_funcall(ropts, oj_to_h_id, 0);
        } else if (Qnil == ropts) {
            return;
        } else {
            rb_raise(rb_eArgError, "options must be a hash.");
        }
    }
    v = rb_hash_lookup(ropts, oj_max_nesting_sym);
    if (Qtrue == v) {
        copts->dump_opts.max_depth = 100;
    } else if (Qfalse == v || Qnil == v) {
        copts->dump_opts.max_depth = MAX_DEPTH;
    } else if (T_FIXNUM == rb_type(v)) {
        copts->dump_opts.max_depth = NUM2INT(v);
        if (0 >= copts->dump_opts.max_depth) {
            copts->dump_opts.max_depth = MAX_DEPTH;
        }
    }
    if (Qnil != (v = rb_hash_lookup(ropts, oj_allow_nan_sym))) {
        if (Qtrue == v) {
            copts->dump_opts.nan_dump = WordNan;
        } else {
            copts->dump_opts.nan_dump = RaiseNan;
        }
    }
    if (Qnil != (v = rb_hash_lookup(ropts, oj_indent_sym))) {
        rb_check_type(v, T_STRING);
        if (sizeof(copts->dump_opts.indent_str) <= (len = RSTRING_LEN(v))) {
            rb_raise(rb_eArgError,
                     "indent string is limited to %lu characters.",
                     (unsigned long)sizeof(copts->dump_opts.indent_str));
        }
        strcpy(copts->dump_opts.indent_str, StringValuePtr(v));
        copts->dump_opts.indent_size = (uint8_t)len;
        copts->dump_opts.use         = true;
    }
    if (Qnil != (v = rb_hash_lookup(ropts, oj_space_sym))) {
        rb_check_type(v, T_STRING);
        if (sizeof(copts->dump_opts.after_sep) <= (len = RSTRING_LEN(v))) {
            rb_raise(rb_eArgError,
                     "space string is limited to %lu characters.",
                     (unsigned long)sizeof(copts->dump_opts.after_sep));
        }
        strcpy(copts->dump_opts.after_sep, StringValuePtr(v));
        copts->dump_opts.after_size = (uint8_t)len;
        copts->dump_opts.use        = true;
    }
    if (Qnil != (v = rb_hash_lookup(ropts, oj_space_before_sym))) {
        rb_check_type(v, T_STRING);
        if (sizeof(copts->dump_opts.before_sep) <= (len = RSTRING_LEN(v))) {
            rb_raise(rb_eArgError,
                     "space_before string is limited to %lu characters.",
                     (unsigned long)sizeof(copts->dump_opts.before_sep));
        }
        strcpy(copts->dump_opts.before_sep, StringValuePtr(v));
        copts->dump_opts.before_size = (uint8_t)len;
        copts->dump_opts.use         = true;
    }
    if (Qnil != (v = rb_hash_lookup(ropts, oj_object_nl_sym))) {
        rb_check_type(v, T_STRING);
        if (sizeof(copts->dump_opts.hash_nl) <= (len = RSTRING_LEN(v))) {
            rb_raise(rb_eArgError,
                     "object_nl string is limited to %lu characters.",
                     (unsigned long)sizeof(copts->dump_opts.hash_nl));
        }
        strcpy(copts->dump_opts.hash_nl, StringValuePtr(v));
        copts->dump_opts.hash_size = (uint8_t)len;
        copts->dump_opts.use       = true;
    }
    if (Qnil != (v = rb_hash_lookup(ropts, oj_array_nl_sym))) {
        rb_check_type(v, T_STRING);
        if (sizeof(copts->dump_opts.array_nl) <= (len = RSTRING_LEN(v))) {
            rb_raise(rb_eArgError,
                     "array_nl string is limited to %lu characters.",
                     (unsigned long)sizeof(copts->dump_opts.array_nl));
        }
        strcpy(copts->dump_opts.array_nl, StringValuePtr(v));
        copts->dump_opts.array_size = (uint8_t)len;
        copts->dump_opts.use        = true;
    }
    if (Qnil != (v = rb_hash_lookup(ropts, oj_quirks_mode_sym))) {
        copts->quirks_mode = (Qtrue == v) ? Yes : No;
    }
    if (Qnil != (v = rb_hash_lookup(ropts, oj_ascii_only_sym))) {
        // generate seems to assume anything except nil and false are true.
        if (Qfalse == v) {
            copts->escape_mode = JXEsc;
        } else {
            copts->escape_mode = ASCIIEsc;
        }
    }
}

static int mimic_limit_arg(VALUE a) {
    if (Qnil == a || T_FIXNUM != rb_type(a)) {
        return -1;
    }
    return NUM2INT(a);
}

/* Document-method: dump
 * call-seq: dump(obj, anIO=nil, limit=nil)
 *
 * Encodes an object as a JSON String.
 *
 * - *obj* [_Object_] object to convert to encode as JSON
 * - *anIO* [_IO_] an IO that allows writing
 * - *limit* [_Fixnum_] ignored
 *
 * Returns [_String_] a JSON string.
 */
static VALUE mimic_dump(int argc, VALUE *argv, VALUE self) {
    struct _out     out;
    struct _options copts = oj_default_options;
    VALUE           rstr;
    VALUE           active_hack[1];

    copts.str_rx.head = NULL;
    copts.str_rx.tail = NULL;

    oj_out_init(&out);

    copts.escape_mode = JXEsc;
    copts.mode        = CompatMode;

    /* seems like this is not correct
    if (No == copts.nilnil && Qnil == *argv) {
        rb_raise(rb_eTypeError, "nil not allowed.");
    }
    */
    copts.dump_opts.max_depth = MAX_DEPTH;  // when using dump there is no limit
    out.omit_nil              = copts.dump_opts.omit_nil;

    if (2 <= argc) {
        int limit;

        // The json gem take a more liberal approach to optional
        // arguments. Expected are (obj, anIO=nil, limit=nil) yet the io
        // argument can be left off completely and the 2nd argument is then
        // the limit.
        if (0 <= (limit = mimic_limit_arg(argv[1]))) {
            copts.dump_opts.max_depth = limit;
        }
        if (3 <= argc && 0 <= (limit = mimic_limit_arg(argv[2]))) {
            copts.dump_opts.max_depth = limit;
        }
    }
    // ActiveSupport in active_support/core_ext/object/json.rb check the
    // optional argument type to to_json and it the argument is a
    // ::JSON::State it calls the JSON gem code otherwise it calls the active
    // support encoder code. To make sure the desired branch is called a
    // default ::JSON::State argument is passed in. Basically a hack to get
    // around the active support hack so two wrongs make a right this time.
    active_hack[0] = rb_funcall(state_class, oj_new_id, 0);
    oj_dump_obj_to_json_using_params(*argv, &copts, &out, 1, active_hack);

    if (0 == out.buf) {
        rb_raise(rb_eNoMemError, "Not enough memory.");
    }
    rstr = rb_utf8_str_new_cstr(out.buf);
    if (2 <= argc && Qnil != argv[1] && rb_respond_to(argv[1], oj_write_id)) {
        VALUE io = argv[1];
        VALUE args[1];

        *args = rstr;
        rb_funcall2(io, oj_write_id, 1, args);
        rstr = io;
    }

    oj_out_free(&out);

    return rstr;
}

// This is the signature for the hash_foreach callback also.
static int mimic_walk(VALUE key, VALUE obj, VALUE proc) {
    switch (rb_type(obj)) {
    case T_HASH: rb_hash_foreach(obj, mimic_walk, proc); break;
    case T_ARRAY: {
        size_t cnt = RARRAY_LEN(obj);
        size_t i;

        for (i = 0; i < cnt; i++) {
            mimic_walk(Qnil, RARRAY_AREF(obj, i), proc);
        }
        break;
    }
    default: break;
    }
    if (Qnil == proc) {
        if (rb_block_given_p()) {
            rb_yield(obj);
        }
    } else {
        VALUE args[1];

        *args = obj;
        rb_proc_call_with_block(proc, 1, args, Qnil);
    }
    return ST_CONTINUE;
}

/* Document-method: restore
 * call-seq: restore(source, proc=nil)
 *
 * Loads a Ruby Object from a JSON source that can be either a String or an
 * IO. If Proc is given or a block is provided it is called with each nested
 * element of the loaded Object.
 *
 * - *source* [_String_|IO] JSON source
 * - *proc* [_Proc_] to yield to on each element or nil
 *
 * Returns [_Object_] the decoded Object.
 */

/* Document-method: load
 * call-seq: load(source, proc=nil)
 *
 * Loads a Ruby Object from a JSON source that can be either a String or an
 * IO. If Proc is given or a block is provided it is called with each nested
 * element of the loaded Object.
 *
 * - *source* [_String_|IO] JSON source
 * - *proc* [_Proc_] to yield to on each element or nil
 *
 * Returns [_Object_] the decode Object.
 */
static VALUE mimic_load(int argc, VALUE *argv, VALUE self) {
    VALUE obj;
    VALUE p = Qnil;

    obj = oj_compat_load(argc, argv, self);
    if (2 <= argc) {
        if (rb_cProc == rb_obj_class(argv[1])) {
            p = argv[1];
        } else if (3 <= argc) {
            if (rb_cProc == rb_obj_class(argv[2])) {
                p = argv[2];
            }
        }
    }
    mimic_walk(Qnil, obj, p);

    return obj;
}

/* Document-method: []
 * call-seq: [](obj, opts={})
 *
 * If the obj argument is a String then it is assumed to be a JSON String and
 * parsed otherwise the obj is encoded as a JSON String.
 *
 * - *obj* [_String_|Hash|Array] object to convert
 * - *opts* [_Hash_] same options as either generate or parse
 *
 * Returns [_Object_]
 */
static VALUE mimic_dump_load(int argc, VALUE *argv, VALUE self) {
    if (1 > argc) {
        rb_raise(rb_eArgError, "wrong number of arguments (0 for 1)");
    }
    if (T_STRING == rb_type(*argv)) {
        return mimic_load(argc, argv, self);
    }
    return mimic_dump(argc, argv, self);
}

static VALUE mimic_generate_core(int argc, VALUE *argv, Options copts) {
    struct _out out;
    VALUE       rstr;

    if (0 == argc) {
        rb_raise(rb_eArgError, "wrong number of arguments (0))");
    }
    memset(out.stack_buffer, 0, sizeof(out.stack_buffer));

    oj_out_init(&out);

    out.omit_nil = copts->dump_opts.omit_nil;
    // For obj.to_json or generate nan is not allowed but if called from dump
    // it is.
    copts->dump_opts.nan_dump = RaiseNan;
    copts->mode               = CompatMode;
    copts->to_json            = Yes;
    if (2 == argc && Qnil != argv[1]) {
        oj_parse_mimic_dump_options(argv[1], copts);
    }
    /* seems like this is not correct
    if (No == copts->nilnil && Qnil == *argv) {
        rb_raise(rb_eTypeError, "nil not allowed.");
    }
    */
    if (1 < argc) {
        oj_dump_obj_to_json_using_params(*argv, copts, &out, argc - 1, argv + 1);
    } else {
        VALUE active_hack[1];

        if (Qundef == state_class) {
            rb_warn("Oj::Rails.mimic_JSON was called implicitly. "
                    "Call it explicitly beforehand if you want to remove this warning.");
            oj_define_mimic_json(0, NULL, Qnil);
        }
        active_hack[0] = rb_funcall(state_class, oj_new_id, 0);
        oj_dump_obj_to_json_using_params(*argv, copts, &out, 1, active_hack);
    }
    if (0 == out.buf) {
        rb_raise(rb_eNoMemError, "Not enough memory.");
    }
    rstr = rb_utf8_str_new_cstr(out.buf);

    oj_out_free(&out);

    return rstr;
}

/* Document-method: fast_generate
 * call-seq: fast_generate(obj, opts=nil)
 * Same as generate().
 * @see generate
 */

/* Document-method: generate
 * call-seq: generate(obj, opts=nil)
 *
 * Encode obj as a JSON String. The obj argument must be a Hash, Array, or
 * respond to to_h or to_json. Options other than those listed such as
 * +:allow_nan+ or +:max_nesting+ are ignored.
 *
 * - *obj* [_Object_|Hash|Array] object to convert to a JSON String
 * - *opts* [_Hash_] options
 * - - *:indent* [_String_] String to use for indentation.
 *   - *:space* [_String_] String placed after a , or : delimiter
 *   - *:space_before*  [_String_] String placed before a : delimiter
 *   - *:object_nl* [_String_] String placed after a JSON object
 *   - *:array_nl* [_String_] String placed after a JSON array
 *   - *:ascii_only* [_Boolean_] if not nil or false then use only ascii characters in the output.
 *     Note JSON.generate does support this even if it is not documented.
 *
 * Returns [_String_] generated JSON.
 */
VALUE
oj_mimic_generate(int argc, VALUE *argv, VALUE self) {
    struct _options copts = oj_default_options;

    copts.str_rx.head = NULL;
    copts.str_rx.tail = NULL;

    return mimic_generate_core(argc, argv, &copts);
}

/* Document-method: pretty_generate
 *	call-seq: pretty_generate(obj, opts=nil)
 *
 * Same as generate() but with different defaults for the spacing options.
 * @see generate
 *
 * Return [_String_] the generated JSON.
 */
VALUE
oj_mimic_pretty_generate(int argc, VALUE *argv, VALUE self) {
    struct _options copts = oj_default_options;
    VALUE           rargs[2];
    volatile VALUE  h;

    // Some (all?) json gem to_json methods need a State instance and not just
    // a Hash. I haven't dug deep enough to find out why but using a State
    // instance and not a Hash gives the desired behavior.
    *rargs = *argv;
    if (0 == argc) {
        rb_raise(rb_eArgError, "wrong number of arguments (0))");
    }
    if (1 == argc || Qnil == argv[1]) {
        h = rb_hash_new();
    } else {
        h = argv[1];
    }
    if (!oj_hash_has_key(h, oj_indent_sym)) {
        rb_hash_aset(h, oj_indent_sym, rb_str_new2("  "));
    }
    if (!oj_hash_has_key(h, oj_space_before_sym)) {
        rb_hash_aset(h, oj_space_before_sym, rb_str_new2(""));
    }
    if (!oj_hash_has_key(h, oj_space_sym)) {
        rb_hash_aset(h, oj_space_sym, rb_str_new2(" "));
    }
    if (!oj_hash_has_key(h, oj_object_nl_sym)) {
        rb_hash_aset(h, oj_object_nl_sym, rb_str_new2("\n"));
    }
    if (!oj_hash_has_key(h, oj_array_nl_sym)) {
        rb_hash_aset(h, oj_array_nl_sym, rb_str_new2("\n"));
    }
    if (Qundef == state_class) {
        rb_warn("Oj::Rails.mimic_JSON was called implicitly. "
                "Call it explicitly beforehand if you want to remove this warning.");
        oj_define_mimic_json(0, NULL, Qnil);
    }
    rargs[1] = rb_funcall(state_class, oj_new_id, 1, h);

    copts.str_rx.head = NULL;
    copts.str_rx.tail = NULL;
    strcpy(copts.dump_opts.indent_str, "  ");
    copts.dump_opts.indent_size = (uint8_t)strlen(copts.dump_opts.indent_str);
    strcpy(copts.dump_opts.before_sep, "");
    copts.dump_opts.before_size = (uint8_t)strlen(copts.dump_opts.before_sep);
    strcpy(copts.dump_opts.after_sep, " ");
    copts.dump_opts.after_size = (uint8_t)strlen(copts.dump_opts.after_sep);
    strcpy(copts.dump_opts.hash_nl, "\n");
    copts.dump_opts.hash_size = (uint8_t)strlen(copts.dump_opts.hash_nl);
    strcpy(copts.dump_opts.array_nl, "\n");
    copts.dump_opts.array_size = (uint8_t)strlen(copts.dump_opts.array_nl);
    copts.dump_opts.use        = true;

    return mimic_generate_core(2, rargs, &copts);
}

static int parse_options_cb(VALUE k, VALUE v, VALUE info) {
    struct _parseInfo *pi = (struct _parseInfo *)info;

    if (oj_symbolize_names_sym == k) {
        pi->options.sym_key = (Qtrue == v) ? Yes : No;
    } else if (oj_quirks_mode_sym == k) {
        pi->options.quirks_mode = (Qtrue == v) ? Yes : No;
    } else if (oj_create_additions_sym == k) {
        pi->options.create_ok = (Qtrue == v) ? Yes : No;
    } else if (oj_allow_nan_sym == k) {
        pi->options.allow_nan = (Qtrue == v) ? Yes : No;
    } else if (oj_hash_class_sym == k) {
        if (Qnil == v) {
            pi->options.hash_class = Qnil;
        } else {
            rb_check_type(v, T_CLASS);
            pi->options.hash_class = v;
        }
    } else if (oj_object_class_sym == k) {
        if (Qnil == v) {
            pi->options.hash_class = Qnil;
        } else {
            rb_check_type(v, T_CLASS);
            pi->options.hash_class = v;
        }
    } else if (oj_array_class_sym == k) {
        if (Qnil == v) {
            pi->options.array_class = Qnil;
        } else {
            rb_check_type(v, T_CLASS);
            pi->options.array_class = v;
        }
    } else if (oj_decimal_class_sym == k) {
        pi->options.compat_bigdec = (oj_bigdecimal_class == v);
    }
    return ST_CONTINUE;
}

static VALUE mimic_parse_core(int argc, VALUE *argv, VALUE self, bool bang) {
    struct _parseInfo pi;
    VALUE             ropts;
    VALUE             args[1];

    rb_scan_args(argc, argv, "11", NULL, &ropts);
    parse_info_init(&pi);
    oj_set_compat_callbacks(&pi);

    pi.err_class = oj_json_parser_error_class;
    // pi.err_class = Qnil;

    pi.options               = oj_default_options;
    pi.options.auto_define   = No;
    pi.options.quirks_mode   = Yes;
    pi.options.allow_invalid = Yes;
    pi.options.empty_string  = No;
    pi.options.create_ok     = No;
    pi.options.allow_nan     = (bang ? Yes : No);
    pi.options.nilnil        = No;
    pi.options.bigdec_load   = RubyDec;
    pi.options.mode          = CompatMode;
    pi.max_depth             = 100;

    if (Qnil != ropts) {
        VALUE v;

        if (T_HASH != rb_type(ropts)) {
            rb_raise(rb_eArgError, "options must be a hash.");
        }
        rb_hash_foreach(ropts, parse_options_cb, (VALUE)&pi);
        v = rb_hash_lookup(ropts, oj_max_nesting_sym);
        if (Qtrue == v) {
            pi.max_depth = 100;
        } else if (Qfalse == v || Qnil == v) {
            pi.max_depth = 0;
        } else if (T_FIXNUM == rb_type(v)) {
            pi.max_depth = NUM2INT(v);
        }
        oj_parse_opt_match_string(&pi.options.str_rx, ropts);
        if (Yes == pi.options.create_ok && Yes == pi.options.sym_key) {
            rb_raise(rb_eArgError, ":symbolize_names and :create_additions can not both be true.");
        }
    }
    *args = *argv;

    if (T_STRING == rb_type(*args)) {
        return oj_pi_parse(1, args, &pi, 0, 0, false);
    } else {
        return oj_pi_sparse(1, args, &pi, 0);
    }
}

/* Document-method: parse
 * call-seq: parse(source, opts=nil)
 *
 * Parses a JSON String or IO into a Ruby Object.  Options other than those
 * listed such as +:allow_nan+ or +:max_nesting+ are ignored. +:object_class+ and
 * +:array_object+ are not supported.
 *
 * - *source* [_String_|IO] source to parse
 * - *opts* [_Hash_] options
 *   - *:symbolize* [Boolean] _names flag indicating JSON object keys should be Symbols instead of
 *     Strings
 *   - *:create_additions* [Boolean] flag indicating a key matching +create_id+ in a JSON object
 *     should trigger the creation of Ruby Object
 *
 * Returns [Object]
 * @see create_id=
 */
VALUE
oj_mimic_parse(int argc, VALUE *argv, VALUE self) {
    return mimic_parse_core(argc, argv, self, false);
}

/* Document-method: parse!
 * call-seq: parse!(source, opts=nil)
 *
 * Same as parse().
 * @see parse
 */
static VALUE mimic_parse_bang(int argc, VALUE *argv, VALUE self) {
    return mimic_parse_core(argc, argv, self, true);
}

/* Document-method: recurse_proc
 * call-seq: recurse_proc(obj, &proc)
 *
 * Yields to the proc for every element in the obj recursively.
 *
 * - *obj* [_Hash_|Array] object to walk
 * - *proc* [_Proc_] to yield to on each element
 */
static VALUE mimic_recurse_proc(VALUE self, VALUE obj) {
    rb_need_block();
    mimic_walk(Qnil, obj, Qnil);

    return Qnil;
}

/* Document-method: create_id=
 * call-seq: create_id=(id)
 *
 * Sets the create_id tag to look for in JSON document. That key triggers the
 * creation of a class with the same name.
 *
 * - *id* [_nil_|String] new create_id
 *
 * Returns [_nil_|_String_] the id.
 */
static VALUE mimic_set_create_id(VALUE self, VALUE id) {
    if (NULL != oj_default_options.create_id) {
        if (oj_json_class != oj_default_options.create_id) {
            OJ_R_FREE((char *)oj_default_options.create_id);
        }
        oj_default_options.create_id     = NULL;
        oj_default_options.create_id_len = 0;
    }
    if (Qnil != id) {
        const char *ptr = StringValueCStr(id);
        size_t      len = RSTRING_LEN(id) + 1;

        oj_default_options.create_id = OJ_R_ALLOC_N(char, len);
        strcpy((char *)oj_default_options.create_id, ptr);
        oj_default_options.create_id_len = len - 1;
    }
    return id;
}

/* Document-method: create_id
 * call-seq: create_id()
 *
 * Returns [_String_] the create_id.
 */
static VALUE mimic_create_id(VALUE self) {
    if (NULL != oj_default_options.create_id) {
        return rb_utf8_str_new(oj_default_options.create_id, oj_default_options.create_id_len);
    }
    return rb_str_new_cstr(oj_json_class);
}

static struct _options mimic_object_to_json_options = {0,              // indent
                                                       No,             // circular
                                                       No,             // auto_define
                                                       No,             // sym_key
                                                       JXEsc,          // escape_mode
                                                       CompatMode,     // mode
                                                       No,             // class_cache
                                                       RubyTime,       // time_format
                                                       No,             // bigdec_as_num
                                                       RubyDec,        // bigdec_load
                                                       false,          // compat_bigdec
                                                       No,             // to_hash
                                                       No,             // to_json
                                                       No,             // as_json
                                                       No,             // raw_json
                                                       No,             // nilnil
                                                       No,             // empty_string
                                                       Yes,            // allow_gc
                                                       Yes,            // quirks_mode
                                                       Yes,            // allow_invalid
                                                       No,             // create_ok
                                                       No,             // allow_nan
                                                       No,             // trace
                                                       No,             // safe
                                                       false,          // sec_prec_set
                                                       No,             // ignore_under
                                                       Yes,            // cache_keys
                                                       0,              // cache_str
                                                       0,              // int_range_min
                                                       0,              // int_range_max
                                                       oj_json_class,  // create_id
                                                       10,             // create_id_len
                                                       3,              // sec_prec
                                                       0,              // float_prec
                                                       "%0.16g",       // float_fmt
                                                       Qnil,           // hash_class
                                                       Qnil,           // array_class
                                                       {
                                                           // dump_opts
                                                           false,     // use
                                                           "",        // indent
                                                           "",        // before_sep
                                                           "",        // after_sep
                                                           "",        // hash_nl
                                                           "",        // array_nl
                                                           0,         // indent_size
                                                           0,         // before_size
                                                           0,         // after_size
                                                           0,         // hash_size
                                                           0,         // array_size
                                                           RaiseNan,  // nan_dump
                                                           false,     // omit_nil
                                                           false,     // omit_null_byte
                                                           100,       // max_depth
                                                       },
                                                       {
                                                           // str_rx
                                                           NULL,    // head
                                                           NULL,    // tail
                                                           {'\0'},  // err
                                                       }};

static VALUE mimic_object_to_json(int argc, VALUE *argv, VALUE self) {
    struct _out     out;
    VALUE           rstr;
    struct _options copts = oj_default_options;

    copts.str_rx.head = NULL;
    copts.str_rx.tail = NULL;

    oj_out_init(&out);

    out.omit_nil  = copts.dump_opts.omit_nil;
    copts.mode    = CompatMode;
    copts.to_json = No;
    if (1 <= argc && Qnil != argv[0]) {
        oj_parse_mimic_dump_options(argv[0], &copts);
    }
    // To be strict the mimic_object_to_json_options should be used but people
    // seem to prefer the option of changing that.
    // oj_dump_obj_to_json(self, &mimic_object_to_json_options, &out);
    oj_dump_obj_to_json_using_params(self, &copts, &out, argc, argv);
    if (NULL == out.buf) {
        rb_raise(rb_eNoMemError, "Not enough memory.");
    }
    rstr = rb_utf8_str_new_cstr(out.buf);

    oj_out_free(&out);

    return rstr;
}

/* Document-method: state
 *	call-seq: state()
 *
 * Returns [_JSON::State_] the JSON::State class.
 */
static VALUE mimic_state(VALUE self) {
    return state_class;
}

void oj_mimic_json_methods(VALUE json) {
    VALUE json_error;
    VALUE generator;
    VALUE ext;
    VALUE verbose;

    // rb_undef_method doesn't work for modules or maybe sometimes
    // doesn't. Anyway setting verbose should hide the warning.
    verbose = rb_gv_get("$VERBOSE");
    rb_gv_set("$VERBOSE", Qfalse);

    rb_undef_method(json, "create_id=");
    rb_define_module_function(json, "create_id=", mimic_set_create_id, 1);
    rb_undef_method(json, "create_id");
    rb_define_module_function(json, "create_id", mimic_create_id, 0);

    rb_undef_method(json, "dump");
    rb_define_module_function(json, "dump", mimic_dump, -1);
    rb_undef_method(json, "load");
    rb_define_module_function(json, "load", mimic_load, -1);
    rb_define_module_function(json, "restore", mimic_load, -1);
    rb_undef_method(json, "recurse_proc");
    rb_define_module_function(json, "recurse_proc", mimic_recurse_proc, 1);
    rb_undef_method(json, "[]");
    rb_define_module_function(json, "[]", mimic_dump_load, -1);

    rb_undef_method(json, "generate");
    rb_define_module_function(json, "generate", oj_mimic_generate, -1);
    rb_undef_method(json, "fast_generate");
    rb_define_module_function(json, "fast_generate", oj_mimic_generate, -1);
    rb_undef_method(json, "pretty_generate");
    rb_define_module_function(json, "pretty_generate", oj_mimic_pretty_generate, -1);
    // For older versions of JSON, the deprecated unparse methods.
    rb_undef_method(json, "unparse");
    rb_define_module_function(json, "unparse", oj_mimic_generate, -1);
    rb_define_module_function(json, "fast_unparse", oj_mimic_generate, -1);
    rb_define_module_function(json, "pretty_unparse", oj_mimic_pretty_generate, -1);

    rb_undef_method(json, "parse");
    rb_define_module_function(json, "parse", oj_mimic_parse, -1);
    rb_undef_method(json, "parse!");
    rb_define_module_function(json, "parse!", mimic_parse_bang, -1);

    rb_undef_method(json, "state");
    rb_define_module_function(json, "state", mimic_state, 0);
    rb_gv_set("$VERBOSE", verbose);

    if (rb_const_defined_at(json, rb_intern("JSONError"))) {
        json_error = rb_const_get(json, rb_intern("JSONError"));
    } else {
        json_error = rb_define_class_under(json, "JSONError", rb_eStandardError);
    }

    rb_global_variable(&oj_json_parser_error_class);
    if (rb_const_defined_at(json, rb_intern("ParserError"))) {
        oj_json_parser_error_class = rb_const_get(json, rb_intern("ParserError"));
    } else {
        oj_json_parser_error_class = rb_define_class_under(json, "ParserError", json_error);
    }

    rb_global_variable(&oj_json_generator_error_class);
    if (rb_const_defined_at(json, rb_intern("GeneratorError"))) {
        oj_json_generator_error_class = rb_const_get(json, rb_intern("GeneratorError"));
    } else {
        oj_json_generator_error_class = rb_define_class_under(json, "GeneratorError", json_error);
    }
    if (rb_const_defined_at(json, rb_intern("NestingError"))) {
        rb_const_get(json, rb_intern("NestingError"));
    } else {
        rb_define_class_under(json, "NestingError", json_error);
    }

    if (rb_const_defined_at(json, rb_intern("Ext"))) {
        ext = rb_const_get_at(json, rb_intern("Ext"));
    } else {
        ext = rb_define_module_under(json, "Ext");
    }
    if (rb_const_defined_at(ext, rb_intern("Generator"))) {
        generator = rb_const_get_at(ext, rb_intern("Generator"));
    } else {
        generator = rb_define_module_under(ext, "Generator");
    }
    if (!rb_const_defined_at(generator, rb_intern("State"))) {
        rb_require("oj/state");
    }
    // Pull in the JSON::State mimic file.
    rb_global_variable(&state_class);
    state_class = rb_const_get_at(generator, rb_intern("State"));
}

/* Document-module: JSON
 *
 * A mimic of the json gem module.
 */
VALUE
oj_define_mimic_json(int argc, VALUE *argv, VALUE self) {
    VALUE dummy;
    VALUE verbose;
    VALUE json;

    // Either set the paths to indicate JSON has been loaded or replaces the
    // methods if it has been loaded.
    if (rb_const_defined_at(rb_cObject, rb_intern("JSON"))) {
        json = rb_const_get_at(rb_cObject, rb_intern("JSON"));
    } else {
        json = rb_define_module("JSON");
    }
    verbose = rb_gv_get("$VERBOSE");
    rb_gv_set("$VERBOSE", Qfalse);
    rb_define_module_function(rb_cObject, "JSON", mimic_dump_load, -1);
    dummy = rb_gv_get("$LOADED_FEATURES");
    if (rb_type(dummy) == T_ARRAY) {
        rb_ary_push(dummy, rb_str_new2("json"));
        if (0 < argc) {
            VALUE mimic_args[1];

            *mimic_args = *argv;
            rb_funcall2(Oj, rb_intern("mimic_loaded"), 1, mimic_args);
        } else {
            rb_funcall2(Oj, rb_intern("mimic_loaded"), 0, 0);
        }
    }
    oj_mimic_json_methods(json);

    if (!rb_const_defined(rb_cObject, rb_intern("ActiveSupport"))) {
        rb_define_method(rb_cObject, "to_json", mimic_object_to_json, -1);
    }

    rb_gv_set("$VERBOSE", verbose);

    oj_default_options         = mimic_object_to_json_options;
    oj_default_options.to_json = Yes;

    return json;
}