Compiler_Module_Binder.H

/*
                          Aleph_w

  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w

  This file is part of Aleph-w library

  Copyright (c) 2002-2026 Leandro Rabindranath Leon

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*/

/** @file Compiler_Module_Binder.H
 *  @brief Reusable binding helpers for linked module surfaces.
 *
 *  This header turns one `Compiler_Module_Link_Result` into a deterministic
 *  binding view that answers which top-level names are actually bindable from
 *  each module after considering local exports, direct imports, and namespace
 *  conflicts. The binding layer intentionally stays shallow: it models visible
 *  top-level names, not full type-checking or member resolution.
 *
 *  @ingroup Utilities
 */

#ifndef COMPILER_MODULE_BINDER_H
#define COMPILER_MODULE_BINDER_H

#include <sstream>
#include <string>

#include <tpl_dynMapTree.H>
#include <Compiler_Module_Linker.H>

namespace Aleph {
/** @brief One top-level name successfully bound in a module namespace. */
struct Compiler_Module_Bound_Name
{
  Compiler_Module_Export_Kind kind = Compiler_Module_Export_Kind::Global;
  std::string name;
  size_t provider_module_index = static_cast<size_t>(-1);
  std::string provider_module_name;
  Source_Span declaration_span;
  bool imported = false;  ///< `false` for local bindings, `true` for direct-imported bindings.
};

/** @brief Bound top-level names visible from one module. */
struct Compiler_Module_Bindings
{
  std::string module_name;
  size_t module_index = static_cast<size_t>(-1);
  size_t order_index = static_cast<size_t>(-1);
  DynArray<Compiler_Module_Bound_Name> names;
};

/** @brief Structural issues emitted while binding linked module surfaces. */
enum class Compiler_Module_Binding_Issue_Kind
{
  Missing_Metadata,
  Ambiguous_Value_Name,
  Ambiguous_Type_Name
};

/** @brief One structural issue reported by the reusable module binder. */
struct Compiler_Module_Binding_Issue
{
  Compiler_Module_Binding_Issue_Kind kind = Compiler_Module_Binding_Issue_Kind::Missing_Metadata;
  size_t module_index = static_cast<size_t>(-1);
  std::string module_name;
  std::string symbol_name;
  std::string referenced_module_name;
  std::string first_provider_module;
  std::string second_provider_module;
  Source_Span span;
};

/** @brief Binding result over one linked module-surface view. */
struct Compiler_Module_Binding_Result
{
  bool valid = true;
  DynArray<Compiler_Module_Bindings> modules;
  DynArray<Compiler_Module_Binding_Issue> issues;
};

/** @brief Returns the stable debug name for one module-binding issue kind. */
inline const char *compiler_module_binding_issue_name(const Compiler_Module_Binding_Issue_Kind kind) noexcept
{
  switch (kind)
    {
    case Compiler_Module_Binding_Issue_Kind::Missing_Metadata:
      return "Missing_Metadata";
    case Compiler_Module_Binding_Issue_Kind::Ambiguous_Value_Name:
      return "Ambiguous_Value_Name";
    case Compiler_Module_Binding_Issue_Kind::Ambiguous_Type_Name:
      return "Ambiguous_Type_Name";
    }

  return "Unknown";
}

namespace Compiler_Module_Binder_Detail {
inline int export_namespace_bucket(const Compiler_Module_Export_Kind kind) noexcept
{
  return kind == Compiler_Module_Export_Kind::Type ? 1 : 0;
}


inline Compiler_Module_Binding_Issue translate_issue(const Compiler_Module_Linkage_Issue &issue)
{
  Compiler_Module_Binding_Issue translated;
  translated.module_index = issue.module_index;
  translated.module_name = issue.module_name;
  translated.span = issue.span;

  switch (issue.kind)
    {
    case Compiler_Module_Linkage_Issue_Kind::Missing_Metadata:
      translated.kind = Compiler_Module_Binding_Issue_Kind::Missing_Metadata;
      translated.referenced_module_name = issue.second_provider_module;
      break;
    case Compiler_Module_Linkage_Issue_Kind::Duplicate_Value_Export:
      translated.kind = Compiler_Module_Binding_Issue_Kind::Ambiguous_Value_Name;
      translated.symbol_name = issue.export_name;
      translated.first_provider_module = issue.first_provider_module;
      translated.second_provider_module = issue.second_provider_module;
      break;
    case Compiler_Module_Linkage_Issue_Kind::Duplicate_Type_Export:
      translated.kind = Compiler_Module_Binding_Issue_Kind::Ambiguous_Type_Name;
      translated.symbol_name = issue.export_name;
      translated.first_provider_module = issue.first_provider_module;
      translated.second_provider_module = issue.second_provider_module;
      break;
    }

  return translated;
}
}  // namespace Compiler_Module_Binder_Detail

/** @brief Binds linked module surfaces into one deterministic name view.
 *
 *  Every visible top-level declaration with no namespace conflict becomes one
 *  binding entry in the corresponding module. Ambiguous names and missing
 *  metadata remain in `issues` and are omitted from the resulting bindings.
 *
 *  @param linkage Linked direct-import surface result.
 *  @return Binding result with deterministic per-module top-level names.
 */
inline Compiler_Module_Binding_Result compiler_bind_module_surfaces(
  const Compiler_Module_Link_Result &linkage)
{
  Compiler_Module_Binding_Result result;
  result.valid = linkage.valid;

  for (size_t i = 0; i < linkage.issues.size(); ++i)
    result.issues.append(Compiler_Module_Binder_Detail::translate_issue(linkage.issues.access(i)));

  for (size_t i = 0; i < linkage.modules.size(); ++i)
    {
      const auto &linked_module = linkage.modules.access(i);
      Compiler_Module_Bindings bindings;
      bindings.module_name = linked_module.module_name;
      bindings.module_index = linked_module.module_index;
      bindings.order_index = linked_module.order_index;

      // Precompute conflict set: keys with more than one distinct provider
      // in the same namespace bucket are ambiguous. O(N log N) single pass.
      DynMapTree<std::string, size_t> first_provider; // key -> source_module_index of first
      DynMapTree<std::string, bool> ambiguous_keys;
      for (size_t j = 0; j < linked_module.visible_exports.size(); ++j)
        {
          const auto &exp = linked_module.visible_exports.access(j);
          const std::string key =
            std::to_string(Compiler_Module_Binder_Detail::export_namespace_bucket(exp.kind))
            + ":" + exp.name;
          const auto *prev = first_provider.search(key);
          if (prev == nullptr)
            {
              first_provider[key] = exp.source_module_index;
            }
          else if (prev->second != exp.source_module_index)
            {
              ambiguous_keys[key] = true;
            }
        }

      // Binding pass: skip ambiguous names; deduplicate with a bound-names map.
      DynMapTree<std::string, bool> bound_keys;
      for (size_t j = 0; j < linked_module.visible_exports.size(); ++j)
        {
          const auto &item = linked_module.visible_exports.access(j);
          const std::string key =
            std::to_string(Compiler_Module_Binder_Detail::export_namespace_bucket(item.kind))
            + ":" + item.name;
          if (ambiguous_keys.search(key) != nullptr)
            continue;
          if (bound_keys.search(key) != nullptr)
            continue;
          bound_keys[key] = true;
          bindings.names.append({item.kind,
                                 item.name,
                                 item.source_module_index,
                                 item.source_module_name,
                                 item.declaration_span,
                                 item.imported});
        }

      result.modules.append(std::move(bindings));
    }

  return result;
}

/** @brief Renders one deterministic text artifact for bound module names.
 *
 *  @param result Binding result to render.
 *  @return Stable plain-text representation of the bound name view.
 */
inline std::string compiler_render_module_bindings(const Compiler_Module_Binding_Result &result)
{
  std::ostringstream out;
  out << "ModuleBindings\n";
  for (size_t i = 0; i < result.modules.size(); ++i)
    {
      const auto &module = result.modules.access(i);
      out << "  Module(" << module.module_name << ") order=" << module.order_index << '\n';
      for (size_t j = 0; j < module.names.size(); ++j)
        {
          const auto &item = module.names.access(j);
          out << "    Bind(" << compiler_module_export_kind_name(item.kind) << "(" << item.name
              << ")) -> " << item.provider_module_name << ' '
              << (item.imported ? "imported" : "local");
          if (item.declaration_span.is_valid())
            out << " @" << item.declaration_span.to_string();
          out << '\n';
        }
    }

  for (size_t i = 0; i < result.issues.size(); ++i)
    {
      const auto &issue = result.issues.access(i);
      out << "  Issue(" << compiler_module_binding_issue_name(issue.kind)
          << ") module=" << issue.module_name;
      if (not issue.symbol_name.empty())
        out << " name=" << issue.symbol_name;
      if (not issue.referenced_module_name.empty())
        out << " dependency=" << issue.referenced_module_name;
      if (not issue.first_provider_module.empty())
        out << " first=" << issue.first_provider_module;
      if (not issue.second_provider_module.empty())
        out << " second=" << issue.second_provider_module;
      if (issue.span.is_valid())
        out << " @" << issue.span.to_string();
      out << '\n';
    }

  return out.str();
}
}  // namespace Aleph

#endif