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#include "src/tint/lang/core/constant/manager.h"

#include "src/tint/lang/core/constant/composite.h"
#include "src/tint/lang/core/constant/scalar.h"
#include "src/tint/lang/core/constant/splat.h"
#include "src/tint/lang/core/type/abstract_float.h"
#include "src/tint/lang/core/type/abstract_int.h"
#include "src/tint/lang/core/type/array.h"
#include "src/tint/lang/core/type/bool.h"
#include "src/tint/lang/core/type/f16.h"
#include "src/tint/lang/core/type/f32.h"
#include "src/tint/lang/core/type/i32.h"
#include "src/tint/lang/core/type/manager.h"
#include "src/tint/lang/core/type/matrix.h"
#include "src/tint/lang/core/type/u32.h"
#include "src/tint/lang/core/type/vector.h"
#include "src/tint/utils/containers/predicates.h"
#include "src/tint/utils/rtti/switch.h"

namespace tint::core::constant {

Manager::Manager() = default;

Manager::Manager(Manager&&) = default;

Manager& Manager::operator=(Manager&& rhs) = default;

Manager::~Manager() = default;

const constant::Value* Manager::Composite(const core::type::Type* type,
                                          VectorRef<const constant::Value*> elements) {
    if (elements.IsEmpty()) {
        return nullptr;
    }

    bool any_zero = false;
    bool all_zero = true;
    bool all_equal = true;
    auto* first = elements.Front();
    for (auto* el : elements) {
        if (!el) {
            return nullptr;
        }
        if (!any_zero && el->AnyZero()) {
            any_zero = true;
        }
        if (all_zero && !el->AllZero()) {
            all_zero = false;
        }
        if (all_equal && el != first) {
            all_equal = false;
        }
    }
    if (all_equal) {
        return Splat(type, elements.Front(), elements.Length());
    }

    return Get<constant::Composite>(type, std::move(elements), all_zero, any_zero);
}

const constant::Splat* Manager::Splat(const core::type::Type* type,
                                      const constant::Value* element,
                                      size_t n) {
    return Get<constant::Splat>(type, element, n);
}

const Scalar<i32>* Manager::Get(i32 value) {
    return Get<Scalar<i32>>(types.i32(), value);
}

const Scalar<u32>* Manager::Get(u32 value) {
    return Get<Scalar<u32>>(types.u32(), value);
}

const Scalar<f32>* Manager::Get(f32 value) {
    return Get<Scalar<f32>>(types.f32(), value);
}

const Scalar<f16>* Manager::Get(f16 value) {
    return Get<Scalar<f16>>(types.f16(), value);
}

const Scalar<bool>* Manager::Get(bool value) {
    return Get<Scalar<bool>>(types.bool_(), value);
}

const Scalar<AFloat>* Manager::Get(AFloat value) {
    return Get<Scalar<AFloat>>(types.AFloat(), value);
}

const Scalar<AInt>* Manager::Get(AInt value) {
    return Get<Scalar<AInt>>(types.AInt(), value);
}

const Value* Manager::Zero(const core::type::Type* type) {
    return Switch(
        type,  //
        [&](const core::type::Vector* v) -> const Value* {
            auto* zero_el = Zero(v->type());
            return Splat(type, zero_el, v->Width());
        },
        [&](const core::type::Matrix* m) -> const Value* {
            auto* zero_el = Zero(m->ColumnType());
            return Splat(type, zero_el, m->columns());
        },
        [&](const core::type::Array* a) -> const Value* {
            if (auto n = a->ConstantCount()) {
                if (auto* zero_el = Zero(a->ElemType())) {
                    return Splat(type, zero_el, n.value());
                }
            }
            return nullptr;
        },
        [&](const core::type::Struct* s) -> const Value* {
            Hashmap<const core::type::Type*, const Value*, 8> zero_by_type;
            Vector<const Value*, 4> zeros;
            zeros.Reserve(s->Members().Length());
            for (auto* member : s->Members()) {
                auto* zero =
                    zero_by_type.GetOrCreate(member->Type(), [&] { return Zero(member->Type()); });
                if (!zero) {
                    return nullptr;
                }
                zeros.Push(zero);
            }
            if (zero_by_type.Count() == 1) {
                // All members were of the same type, so the zero value is the same for all members.
                return Splat(type, zeros[0], s->Members().Length());
            }
            return Composite(s, std::move(zeros));
        },
        [&](Default) -> const Value* {
            return Switch(
                type,                                                              //
                [&](const core::type::AbstractInt*) { return Get(AInt(0)); },      //
                [&](const core::type::AbstractFloat*) { return Get(AFloat(0)); },  //
                [&](const core::type::I32*) { return Get(i32(0)); },               //
                [&](const core::type::U32*) { return Get(u32(0)); },               //
                [&](const core::type::F32*) { return Get(f32(0)); },               //
                [&](const core::type::F16*) { return Get(f16(0)); },               //
                [&](const core::type::Bool*) { return Get(false); });
        });
}

}  // namespace tint::core::constant