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#include "src/tint/lang/core/ir/transform/binding_remapper.h"

#include <utility>

#include "src/tint/lang/core/ir/module.h"
#include "src/tint/lang/core/ir/validator.h"
#include "src/tint/lang/core/ir/var.h"

using namespace tint::core::number_suffixes;  // NOLINT

namespace tint::core::ir::transform {

namespace {

void Run(ir::Module& ir, const std::unordered_map<BindingPoint, BindingPoint>& binding_points) {
    if (binding_points.empty()) {
        return;
    }
    if (ir.root_block->IsEmpty()) {
        return;
    }

    // Find binding resources.
    for (auto inst : *ir.root_block) {
        auto* var = inst->As<Var>();
        if (!var || !var->Alive()) {
            continue;
        }

        auto bp = var->BindingPoint();
        if (!bp) {
            continue;
        }

        // Replace group and binding index if requested.
        auto to = binding_points.find(bp.value());
        if (to != binding_points.end()) {
            var->SetBindingPoint(to->second.group, to->second.binding);
        }
    }
}

}  // namespace

Result<SuccessType> BindingRemapper(
    Module& ir,
    const std::unordered_map<BindingPoint, BindingPoint>& binding_points) {
    core::ir::AssertValid(ir, kBindingRemapperCapabilities, "before core.BindingRemapper");

    Run(ir, binding_points);

    return Success;
}

}  // namespace tint::core::ir::transform
