rutie 0.13.1

use std::ffi::CStr;

use crate::{
    binding::symbol,
    helpers::scan_args::ScanArgsFormat,
    rubysys::{class, typed_data, types::RBasic},
    typed_data::DataTypeWrapper,
    types::{c_int, c_void, Callback, CallbackPtr, Id, Value, ValueType},
    util, Object,
};

pub fn define_class(name: &str, superclass: Value) -> Value {
    let name = util::str_to_cstring(name);

    unsafe { class::rb_define_class(name.as_ptr(), superclass) }
}

pub fn define_nested_class(outer: Value, name: &str, superclass: Value) -> Value {
    let name = util::str_to_cstring(name);

    unsafe { class::rb_define_class_under(outer, name.as_ptr(), superclass) }
}

pub fn const_get(klass: Value, name: &str) -> Value {
    unsafe { class::rb_const_get(klass, symbol::internal_id(name)) }
}

pub fn const_set(klass: Value, name: &str, value: Value) {
    let name = util::str_to_cstring(name);

    unsafe { class::rb_define_const(klass, name.as_ptr(), value) };
}

pub fn object_class(object: Value) -> Value {
    unsafe { class::rb_obj_class(object) }
}

pub fn superclass(klass: Value) -> Value {
    unsafe { class::rb_class_superclass(klass) }
}

pub fn singleton_class(object: Value) -> Value {
    unsafe { class::rb_singleton_class(object) }
}

pub fn ancestors(klass: Value) -> Value {
    unsafe { class::rb_mod_ancestors(klass) }
}

pub fn new_instance(klass: Value, arguments: &[Value]) -> Value {
    let (argc, argv) = util::process_arguments(arguments);

    unsafe { class::rb_class_new_instance(argc, argv, klass) }
}

pub fn instance_variable_get(object: Value, name: &str) -> Value {
    unsafe { class::rb_ivar_get(object, symbol::internal_id(name)) }
}

pub fn instance_variable_set(object: Value, name: &str, value: Value) -> Value {
    unsafe { class::rb_ivar_set(object, symbol::internal_id(name), value) }
}

pub fn define_attribute(object: Value, name: &str, reader: bool, writer: bool) {
    let name = util::str_to_cstring(name);
    let reader = util::bool_to_c_int(reader);
    let writer = util::bool_to_c_int(writer);

    unsafe { class::rb_define_attr(object, name.as_ptr(), reader, writer) };
}

pub fn respond_to(object: Value, method: &str) -> bool {
    let result = unsafe { class::rb_respond_to(object, symbol::internal_id(method)) };

    util::c_int_to_bool(result)
}

pub fn define_method<I: Object, O: Object>(klass: Value, name: &str, callback: Callback<I, O>) {
    let name = util::str_to_cstring(name);

    unsafe {
        class::rb_define_method(klass, name.as_ptr(), callback as CallbackPtr, -1);
    }
}

pub fn define_private_method<I: Object, O: Object>(
    klass: Value,
    name: &str,
    callback: Callback<I, O>,
) {
    let name = util::str_to_cstring(name);

    unsafe {
        class::rb_define_private_method(klass, name.as_ptr(), callback as CallbackPtr, -1);
    }
}

pub fn define_singleton_method<I: Object, O: Object>(
    klass: Value,
    name: &str,
    callback: Callback<I, O>,
) {
    let name = util::str_to_cstring(name);

    unsafe {
        class::rb_define_singleton_method(klass, name.as_ptr(), callback as CallbackPtr, -1);
    }
}

pub fn wrap_data<T>(klass: Value, data: T, wrapper: &dyn DataTypeWrapper<T>) -> Value {
    let data = Box::into_raw(Box::new(data)) as *mut c_void;

    unsafe { typed_data::rb_data_typed_object_wrap(klass, data, wrapper.data_type()) }
}

pub fn get_data<T>(object: Value, wrapper: &dyn DataTypeWrapper<T>) -> &mut T {
    unsafe {
        let data = typed_data::rb_check_typeddata(object, wrapper.data_type());

        &mut *(data as *mut T)
    }
}

pub fn is_frozen(object: Value) -> Value {
    unsafe { class::rb_obj_frozen_p(object) }
}

pub fn freeze(object: Value) -> Value {
    unsafe { class::rb_obj_freeze(object) }
}

pub fn is_eql(object1: Value, object2: Value) -> bool {
    util::c_int_to_bool(unsafe { class::rb_eql(object1, object2) })
}

pub fn equals(object1: Value, object2: Value) -> Value {
    unsafe { class::rb_equal(object1, object2) }
}

pub fn is_kind_of(object: Value, klass: Value) -> bool {
    unsafe { class::rb_obj_is_kind_of(object, klass) }.is_true()
}

pub fn define_alias(klass: Value, new_name: &str, old_name: &str) {
    let new_name = util::str_to_cstring(new_name);
    let old_name = util::str_to_cstring(old_name);

    unsafe { class::rb_define_alias(klass, new_name.as_ptr(), old_name.as_ptr()) };
}

pub fn undef_method(klass: Value, name: &str) {
    let name = util::str_to_cstring(name);

    unsafe { class::rb_undef_method(klass, name.as_ptr()) };
}

pub fn define_alloc_func(klass: Value, func: class::AllocFunction) {
    unsafe { class::rb_define_alloc_func(klass, func) };
}

pub fn undef_alloc_func(klass: Value) {
    unsafe { class::rb_undef_alloc_func(klass) };
}

// Looks up the keywords in `table` (required ones first) in `keyword_hash`
// (an empty hash when it is `nil`), writing them to `values`. Found keys are
// removed from `keyword_hash`; missing optional keywords are left `Qundef`.
// Raises `ArgumentError` for missing required or (unless `allow_extra`)
// unknown keywords, so the caller owns `table` and `values`.
pub fn get_kwargs(
    keyword_hash: Value,
    table: &[Id],
    required: usize,
    allow_extra: bool,
    values: &mut [Value],
) {
    assert!(required <= table.len() && values.len() >= table.len());

    let optional = (table.len() - required) as c_int;
    let optional = if allow_extra { -1 - optional } else { optional };

    unsafe {
        class::rb_get_kwargs(
            keyword_hash,
            table.as_ptr(),
            required as c_int,
            optional,
            values.as_mut_ptr(),
        )
    };
}

// The most `VALUE *` outputs any `rb_scan_args` format can have:
// 9 required + 9 optional + splat + 9 post + keywords + block.
pub const SCAN_ARGS_MAX_VARIABLES: usize = 30;

// `rb_scan_args` takes one `VALUE *` per variable in `format`. C ignores
// surplus variadic arguments, so all `SCAN_ARGS_MAX_VARIABLES` slots of
// `out` are always passed and `rb_scan_args` fills as many as it needs.
//
// Raises `ArgumentError` on an arity mismatch, so the caller owns `format`
// and `out`.
// How a trailing `Hash` is treated (`rb_scan_args_kw`'s `kw_flag`).
pub const SCAN_ARGS_PASS_CALLED_KEYWORDS: c_int = 0;
pub const SCAN_ARGS_LAST_HASH_KEYWORDS: c_int = 3;

pub fn scan_args(
    arguments: &[Value],
    format: &CStr,
    out: &mut [Value; SCAN_ARGS_MAX_VARIABLES],
    kw_flag: c_int,
) -> c_int {
    // `rb_scan_args` aborts the process on a format it cannot parse.
    let valid = format
        .to_str()
        .map(|format| ScanArgsFormat::parse(format).is_ok())
        .unwrap_or(false);
    assert!(valid, "invalid scan args format");

    let (argc, argv) = util::process_arguments(arguments);
    let o = out.as_mut_ptr();

    unsafe {
        class::rb_scan_args_kw(
            kw_flag,
            argc,
            argv,
            format.as_ptr(),
            o,
            o.add(1),
            o.add(2),
            o.add(3),
            o.add(4),
            o.add(5),
            o.add(6),
            o.add(7),
            o.add(8),
            o.add(9),
            o.add(10),
            o.add(11),
            o.add(12),
            o.add(13),
            o.add(14),
            o.add(15),
            o.add(16),
            o.add(17),
            o.add(18),
            o.add(19),
            o.add(20),
            o.add(21),
            o.add(22),
            o.add(23),
            o.add(24),
            o.add(25),
            o.add(26),
            o.add(27),
            o.add(28),
            o.add(29),
        )
    }
}

pub fn is_method_defined(klass: Value, name: &str, include_private: bool) -> bool {
    // `ex` bit 0x01 leaves out private methods.
    let ex = if include_private { 0 } else { 1 };

    unsafe { class::rb_method_boundp(klass, symbol::internal_id(name), ex) != 0 }
}

pub fn class_name(klass: Value) -> Value {
    unsafe { class::rb_class_name(klass) }
}

pub fn class_path(klass: Value) -> Value {
    unsafe { class::rb_class_path(klass) }
}

pub fn module_name(module: Value) -> Value {
    unsafe { class::rb_mod_name(module) }
}

pub fn inherited_p(module: Value, other: Value) -> Value {
    unsafe { class::rb_class_inherited_p(module, other) }
}

pub fn include_p(module: Value, other: Value) -> bool {
    unsafe { class::rb_mod_include_p(module, other) }.is_true()
}

pub fn module_eval(module: Value, code: &str) -> Value {
    let arguments = [crate::binding::string::new_utf8(code)];
    let (argc, argv) = util::process_arguments(&arguments);

    unsafe { class::rb_mod_module_eval(argc, argv, module) }
}

pub fn instance_methods(module: Value, include_inherited: bool) -> Value {
    let arguments = [util::bool_to_value(include_inherited)];
    let (argc, argv) = util::process_arguments(&arguments);

    unsafe { class::rb_class_instance_methods(argc, argv, module) }
}

pub fn is_class_variable_defined(klass: Value, name: &str) -> bool {
    unsafe { class::rb_cvar_defined(klass, symbol::internal_id(name)) }.is_true()
}

pub fn class_variable_get(klass: Value, name: &str) -> Value {
    unsafe { class::rb_cvar_get(klass, symbol::internal_id(name)) }
}

pub fn class_variable_set(klass: Value, name: &str, value: Value) {
    unsafe { class::rb_cvar_set(klass, symbol::internal_id(name), value) }
}

pub fn is_const_defined(klass: Value, name: &str) -> bool {
    util::c_int_to_bool(unsafe { class::rb_const_defined(klass, symbol::internal_id(name)) })
}

pub fn is_const_defined_at(klass: Value, name: &str) -> bool {
    util::c_int_to_bool(unsafe { class::rb_const_defined_at(klass, symbol::internal_id(name)) })
}

pub fn const_remove(module: Value, name: &str) -> Value {
    unsafe { class::rb_const_remove(module, symbol::internal_id(name)) }
}

// Raises `ArgumentError` for an unknown path, so the caller owns `path`.
pub fn path_to_class(path: &CStr) -> Value {
    unsafe { class::rb_path2class(path.as_ptr()) }
}

pub fn define_global_const(name: &str, value: Value) {
    let name = util::str_to_cstring(name);

    unsafe { class::rb_define_global_const(name.as_ptr(), value) }
}

pub fn subclasses(klass: Value) -> Value {
    unsafe { class::rb_class_subclasses(klass) }
}

// Raises `TypeError` unless `klass` is a singleton class.
pub fn attached_object(klass: Value) -> Value {
    unsafe { class::rb_class_attached_object(klass) }
}

pub fn refinement_new() -> Value {
    unsafe { class::rb_refinement_new() }
}

// Returns the value of the class variable and the class or module that
// defines it. Raises `NameError` when it is not defined, and `RuntimeError`
// when a class and its ancestor both define it ("overtaken").
pub fn class_variable_find(klass: Value, name: &str) -> (Value, Value) {
    let mut front = Value::from(0);
    let value = unsafe { class::rb_cvar_find(klass, symbol::internal_id(name), &mut front) };

    // A module in the ancestors is found through its `T_ICLASS`, which must
    // not reach Ruby; its `klass` is the module itself.
    if front.ty() == ValueType::IClass {
        front = Value::from(unsafe { (*(front.value as *const RBasic)).klass });
    }

    (value, front)
}

// Raises `NameError` when `module` does not define the constant itself, and
// `FrozenError` when it is frozen, so the caller owns `name`.
pub fn deprecate_constant(module: Value, name: &CStr) {
    unsafe { class::rb_deprecate_constant(module, name.as_ptr()) }
}