/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <thrift/compiler/sema/standard_validator.h>

#include <algorithm>
#include <set>
#include <string>
#include <unordered_map>

#include <boost/algorithm/string/split.hpp>
#include <fmt/ranges.h>

#include <thrift/compiler/ast/t_enum.h>
#include <thrift/compiler/ast/t_enum_value.h>
#include <thrift/compiler/ast/t_field.h>
#include <thrift/compiler/ast/t_function.h>
#include <thrift/compiler/ast/t_interface.h>
#include <thrift/compiler/ast/t_named.h>
#include <thrift/compiler/ast/t_node.h>
#include <thrift/compiler/ast/t_service.h>
#include <thrift/compiler/ast/t_struct.h>
#include <thrift/compiler/ast/t_structured.h>
#include <thrift/compiler/ast/t_throws.h>
#include <thrift/compiler/ast/t_type.h>
#include <thrift/compiler/ast/t_typedef.h>
#include <thrift/compiler/ast/t_union.h>
#include <thrift/compiler/gen/cpp/reference_type.h>
#include <thrift/compiler/gen/cpp/type_resolver.h>
#include <thrift/compiler/lib/cpp2/util.h>
#include <thrift/compiler/lib/reserved_identifier_name.h>
#include <thrift/compiler/lib/uri.h>
#include <thrift/compiler/sema/const_checker.h>
#include <thrift/compiler/sema/explicit_include_validator.h>
#include <thrift/compiler/sema/scope_validator.h>

namespace apache {
namespace thrift {
namespace compiler {

namespace {
const t_structured* get_mixin_type(const t_field& field) {
  if (cpp2::is_mixin(field)) {
    return dynamic_cast<const t_structured*>(field.type()->get_true_type());
  }
  return nullptr;
}

bool has_experimental_annotation(diagnostic_context& ctx, const t_named& node) {
  if (node.find_structured_annotation_or_null(kExperimentalUri)) {
    return true;
  }
  for (int pos = ctx.nodes().size() - 1; pos >= 0; --pos) {
    const auto* parent = dynamic_cast<const t_named*>(ctx.nodes().at(pos));
    if (parent != nullptr &&
        parent->find_structured_annotation_or_null(kExperimentalUri)) {
      return true;
    }
  }
  return false;
}

bool has_lazy_field(const t_structured& node) {
  for (const auto& field : node.fields()) {
    if (cpp2::is_lazy(&field)) {
      return true;
    }
  }
  return false;
}

// Reports an existing name was redefined within the given parent node.
void report_redef_error(
    diagnostics_engine& diags,
    const char* kind,
    std::string_view name,
    const t_named& parent,
    const t_node& child,
    const t_node& /*existing*/) {
  // TODO(afuller): Use `existing` to provide more detail in the
  // diagnostic.
  diags.error(
      child, "{} `{}` is already defined for `{}`.", kind, name, parent.name());
}

// Helper for checking for the redefinition of a name in the context of a node.
class redef_checker {
 public:
  redef_checker(
      diagnostics_engine& diags, const char* kind, const t_named& parent)
      : diags_(diags), kind_(kind), parent_(parent) {}

  // Checks if the given `name`, derived from `node` via `child`, has already
  // been defined.
  //
  // For example, a mixin field causes all fields of the mixin type to be
  // inherited. In this case 'node' wold be the mixin type, from which `name`
  // was derived, while `child` is the mixin field that caused the name to be
  // inherited.
  void check(std::string_view name, const t_named& node, const t_node& child) {
    const t_named* existing = insert(name, node);
    if (!existing) {
      return;
    }
    if (&node == &parent_ && existing == &parent_) {
      // The degenerate case where parent_ is conflicting with itself.
      report_redef_error(diags_, kind_, name, parent_, child, *existing);
    } else {
      diags_.error(
          child,
          "{} `{}.{}` and `{}.{}` can not have same name in `{}`.",
          kind_,
          node.name(),
          name,
          existing->name(),
          name,
          parent_.name());
    }
  }

  // Helpers for the common case where the names are from child t_nameds of
  // the parent.
  //
  // For example, all functions in an interface.
  void check(const t_named& child) {
    if (const t_named* existing = insert(child.name(), child)) {
      report_redef_error(
          diags_, kind_, child.name(), parent_, child, *existing);
    }
  }

  template <typename Cs>
  void check_all(const Cs& children) {
    for (const t_named& child : children) {
      check(child);
    }
  }

 private:
  const t_named* insert(std::string_view name, const t_named& node) {
    auto [it, success] = seen_.emplace(name, &node);
    if (success) {
      return nullptr;
    }
    const t_named* existing = it->second;
    seen_[name] = &node;
    return existing;
  }

  diagnostics_engine& diags_;
  const char* kind_;
  const t_named& parent_;

  std::unordered_map<std::string_view, const t_named*> seen_;
};

// Helper for validating the adapters
class adapter_or_wrapper_checker {
 public:
  explicit adapter_or_wrapper_checker(diagnostic_context& ctx) : ctx_(ctx) {}

  // Checks if adapter name is provided
  // Do not allow composing two structured annotations on typedef
  void check(
      const t_named& node,
      const char* structured_adapter_annotation,
      const char* structured_adapter_annotation_error_name,
      const char* name) {
    const t_const* adapter_annotation =
        node.find_structured_annotation_or_null(structured_adapter_annotation);
    if (!adapter_annotation) {
      return;
    }

    try {
      adapter_annotation->get_value_from_structured_annotation(name);
    } catch (const std::exception& e) {
      ctx_.error("{}", e.what());
      return;
    }

    if (const auto* typedf = dynamic_cast<const t_typedef*>(&node)) {
      if (t_typedef::get_first_structured_annotation_or_null(
              &*typedf->type(), structured_adapter_annotation)) {
        ctx_.error(
            "The `{}` annotation cannot be annotated more than once in all "
            "typedef levels in `{}`.",
            structured_adapter_annotation_error_name,
            node.name());
      }
    }
  }

  // Do not allow composing structured annotation on field/typedef
  void check(
      const t_field& field,
      const char* structured_adapter_annotation,
      const char* structured_adapter_annotation_error_name,
      bool disallow_structured_annotations_on_both_field_and_typedef) {
    if (!field.type().resolved()) {
      return;
    }
    auto type = field.type().get_type();

    bool structured_annotation_on_field =
        field.find_structured_annotation_or_null(structured_adapter_annotation);

    bool structured_annotation_on_typedef =
        t_typedef::get_first_structured_annotation_or_null(
            type, structured_adapter_annotation) != nullptr;

    if (disallow_structured_annotations_on_both_field_and_typedef &&
        structured_annotation_on_field && structured_annotation_on_typedef) {
      ctx_.error(
          "`{}` cannot be applied on both field and typedef in `{}`.",
          structured_adapter_annotation_error_name,
          field.name());
    }
  }

  // If a type is wrapped itself or is a container of wrapped types, then it
  // cannot be adapted
  void check(
      const t_named& node,
      const char* structured_adapter_annotation,
      const char* structured_wrapper_annotation,
      const char* structured_adapter_annotation_error_name,
      const char* structured_wrapper_annotation_error_name) {
    bool has_adapter_annotation =
        node.find_structured_annotation_or_null(structured_adapter_annotation);
    if (!has_adapter_annotation) {
      return;
    }
    const t_type* type;
    if (const auto* field = dynamic_cast<const t_field*>(&node)) {
      if (!field->type().resolved()) {
        return;
      }
      type = field->type().get_type();
    } else if (const auto* typdef = dynamic_cast<const t_typedef*>(&node)) {
      type = typdef->get_type();
    } else {
      return;
    }

    auto has_wrapper =
        type->find_structured_annotation_or_null(structured_wrapper_annotation);
    std::string typedef_name = type->name();
    while (!has_wrapper) {
      if (const auto* inner_typedf = dynamic_cast<const t_typedef*>(type)) {
        has_wrapper = inner_typedf->find_structured_annotation_or_null(
            structured_wrapper_annotation);
        typedef_name = inner_typedf->name();
        type = inner_typedf->get_type();
      } else if (type->is_container()) {
        if (const auto* map = dynamic_cast<const t_map*>(type)) {
          type = map->get_val_type();
        } else if (const auto* list = dynamic_cast<const t_list*>(type)) {
          type = list->get_elem_type();
        } else {
          break;
        }
      } else if (type->is_struct()) {
        has_wrapper = type->find_structured_annotation_or_null(
            structured_wrapper_annotation);
        typedef_name = type->name();
        break;
      } else {
        break;
      }
    }
    if (has_wrapper) {
      ctx_.error(
          "`{}` on `{}` cannot be combined with `{}` on `{}`.",
          structured_adapter_annotation_error_name,
          node.name(),
          structured_wrapper_annotation_error_name,
          typedef_name);
    }
  }

 private:
  diagnostic_context& ctx_;
};

struct service_metadata {
  std::unordered_map<std::string_view, const t_service*>
      function_name_to_service;

  service_metadata(node_metadata_cache& cache, const t_service& node) {
    if (node.extends() != nullptr) {
      // Add all the inherited functions.
      function_name_to_service =
          cache.get<service_metadata>(*node.extends()).function_name_to_service;
    }
    // Add all the directly defined functions.
    for (const auto& function : node.functions()) {
      function_name_to_service[function.name()] = &node;
    }
  }
};

struct structured_metadata {
  std::unordered_map<std::string_view, const t_structured*>
      field_name_to_parent;

  structured_metadata(node_metadata_cache& cache, const t_structured& node) {
    for (const auto& field : node.fields()) {
      if (const auto* mixin = get_mixin_type(field)) {
        // Add all the inherited mixin fields from field.
        auto mixin_metadata = cache.get<structured_metadata>(*mixin);
        for (auto [key, value] : mixin_metadata.field_name_to_parent) {
          field_name_to_parent[key] = value;
        }
      }
      // Add the directly defined field.
      field_name_to_parent[field.name()] = &node;
    }
  }
};

void validate_identifier_name_is_not_reserved(
    diagnostic_context& ctx, const t_named& node) {
  static const std::string reserved_idl_string = "fbthrift";
  // Bypass the check any of the cases below.
  //  1. the node was generated.
  //  2. @thrift.AllowedReservedIdentifierName is present.
  if (node.generated() ||
      node.find_structured_annotation_or_null(
          kAllowReservedIdentifierNameUri) != nullptr) {
    return;
  }
  ctx.check(
      !is_reserved_identifier_name(node.name()),
      "`{}` is a reserved identifier name. Choose a different name that does not contain `fbthrift`.",
      node.name());
}

void validate_interface_function_name_uniqueness(
    diagnostic_context& ctx, const t_interface& node) {
  // Check for a redefinition of a function in the same interface.
  redef_checker(ctx, "Function", node).check_all(node.functions());
}

// Checks for a redefinition of an inherited function.
void validate_extends_service_function_name_uniqueness(
    diagnostic_context& ctx, const t_service& node) {
  if (node.extends() == nullptr) {
    return;
  }

  const auto& extends_metadata =
      ctx.cache().get<service_metadata>(*node.extends());
  for (const auto& function : node.functions()) {
    auto service =
        extends_metadata.function_name_to_service.find(function.name());
    if (service != extends_metadata.function_name_to_service.end()) {
      ctx.error(
          function,
          "Function `{0}.{2}` redefines `{1}.{2}`.",
          node.name(),
          service->second->get_full_name(),
          function.name());
    }
  }
}

void validate_throws_exceptions(diagnostic_context& ctx, const t_throws& node) {
  for (const auto& except : node.fields()) {
    auto except_type = except.type()->get_true_type();
    ctx.check(
        dynamic_cast<const t_exception*>(except_type),
        except,
        "Non-exception type, `{}`, in throws.",
        except_type->name());
  }
}

// Checks for a redefinition of a field in the same t_structured, including
// those inherited via mixin fields.
void validate_field_names_uniqueness(
    diagnostic_context& ctx, const t_structured& node) {
  redef_checker checker(ctx, "Field", node);
  for (const auto& field : node.fields()) {
    // Check the directly defined field.
    checker.check(field.name(), node, field);

    // Check any transtively defined fields via a mixin annotation.
    if (const auto* mixin = get_mixin_type(field)) {
      const auto& mixin_metadata = ctx.cache().get<structured_metadata>(*mixin);
      for (auto [name, parent] : mixin_metadata.field_name_to_parent) {
        checker.check(name, *parent, field);
      }
    }
  }
}

// @thrift.ExceptionMessage annotation is only valid in exceptions.
// This validator checks if the node that contains any field
// with that annotation is an exception definiton.
void validate_exception_message_annotation_is_only_in_exceptions(
    diagnostic_context& ctx, const t_structured& node) {
  for (const auto& f : node.fields()) {
    if (f.find_structured_annotation_or_null(kExceptionMessageUri)) {
      ctx.check(
          node.is_exception(),
          f,
          "@thrift.ExceptionMessage annotation is only allowed in exception definitions. '{}' is not an exception.",
          node.name());
    }
  }
}

// Checks the attributes of fields in a union.
void validate_union_field_attributes(
    diagnostic_context& ctx, const t_union& node) {
  for (const auto& field : node.fields()) {
    if (field.qualifier() == t_field_qualifier::optional ||
        field.qualifier() == t_field_qualifier::required) {
      ctx.error(
          field,
          "Unions cannot contain qualified fields. Remove `{}` qualifier from "
          "field `{}`.",
          field.qualifier() == t_field_qualifier::required ? "required"
                                                           : "optional",
          field.name());
    } else if (field.find_structured_annotation_or_null(kTerseWriteUri)) {
      ctx.error(
          field,
          "`@thrift.TerseWrite` cannot be applied to union fields (in `{}`).",
          node.name());
    }
  }
}

void validate_boxed_field_attributes(
    diagnostic_context& ctx, const t_field& node) {
  if (gen::cpp::find_ref_type(node) == gen::cpp::reference_type::none) {
    return;
  }

  bool ref = node.has_annotation({
                 "cpp.ref",
                 "cpp2.ref",
                 "cpp.ref_type",
                 "cpp2.ref_type",
             }) ||
      node.find_structured_annotation_or_null(kCppRefUri);

  bool box = node.has_annotation({
                 "cpp.box",
                 "thrift.box",
             }) ||
      node.find_structured_annotation_or_null(kBoxUri);

  bool intern_box = node.find_structured_annotation_or_null(kInternBoxUri);

  if (ref + box + intern_box > 1) {
    ctx.error(
        node,
        "The {} annotation cannot be combined with the other reference annotations. "
        "Only annotate a single reference annotations from `{}`.",
        intern_box ? "`@thrift.InternBox`"
            : box  ? "`@thrift.Box`"
                   : "`@cpp.Ref`",
        node.name());
  }

  if (box) {
    ctx.check(
        dynamic_cast<const t_union*>(ctx.parent()) ||
            node.qualifier() == t_field_qualifier::optional,
        "The `thrift.box` annotation can only be used with optional fields. "
        "Make sure `{}` is optional.",
        node.name());
  }

  if (intern_box) {
    ctx.check(
        node.type()->get_true_type()->is_struct(),
        "The `@thrift.InternBox` annotation can only be used with a struct field.");
    // TODO(dokwon): Add support for custom defaults and remove this check.
    ctx.check(
        !node.get_value(),
        "The `@thrift.InternBox` annotation currently does not support a field with custom default.");
    ctx.check(
        node.qualifier() == t_field_qualifier::none ||
            node.qualifier() == t_field_qualifier::terse,
        "The `@thrift.InternBox` annotation can only be used with unqualified or terse fields."
        " Make sure `{}` is unqualified or annotated with `@thrift.TerseWrite`.",
        node.name());
  }
}

// Checks the attributes of a mixin field.
void validate_mixin_field_attributes(
    diagnostic_context& ctx, const t_field& node) {
  if (!cpp2::is_mixin(node)) {
    return;
  }

  auto* ttype = node.type()->get_true_type();
  ctx.check(
      typeid(*ttype) == typeid(t_struct) || typeid(*ttype) == typeid(t_union),
      "Mixin field `{}` type must be a struct or union. Found `{}`.",
      node.name(),
      ttype->get_name());

  if (const auto* parent = dynamic_cast<const t_union*>(ctx.parent())) {
    ctx.error(
        "Union `{}` cannot contain mixin field `{}`.",
        parent->name(),
        node.name());
  } else if (node.qualifier() == t_field_qualifier::optional) {
    // Nothing technically stops us from marking optional field mixin.
    // However, this will bring surprising behavior. e.g. `foo.bar_ref()`
    // might throw `bad_field_access` if `bar` is inside optional mixin
    // field.
    ctx.error("Mixin field `{}` cannot be optional.", node.name());
  }
}

void validate_required_field(diagnostic_context& ctx, const t_field& field) {
  if (field.qualifier() == t_field_qualifier::required) {
    ctx.warning(
        field,
        "The 'required' qualifier is deprecated and ignored by most language implementations."
        " Leave the field unqualified instead.");
  }
}

void validate_enum_value_name_uniqueness(
    diagnostic_context& ctx, const t_enum& node) {
  redef_checker(ctx, "Enum value", node).check_all(node.values());
}

void validate_enum_value_uniqueness(
    diagnostic_context& ctx, const t_enum& node) {
  std::unordered_map<int32_t, const t_enum_value*> values;
  for (const auto& value : node.values()) {
    auto prev = values.emplace(value.get_value(), &value);
    ctx.check(
        prev.second,
        value,
        "Duplicate value `{}={}` with value `{}` in enum `{}`.",
        value.name(),
        value.get_value(),
        prev.first->second->name(),
        node.name());
  }
}

void validate_enum_value(diagnostic_context& ctx, const t_enum_value& node) {
  if (!node.has_value()) {
    ctx.error(
        "The enum value, `{}`, must have an explicitly assigned value.",
        node.name());
  }
}

void validate_const_type_and_value(
    diagnostic_context& ctx, const t_const& node) {
  check_const_rec(ctx, node, node.type(), node.value());
  ctx.check(
      !node.find_structured_annotation_or_null(kCppAdapterUri) ||
          has_experimental_annotation(ctx, node),
      "Using adapters on const `{}` is only allowed in the experimental mode.",
      node.name());
}

void validate_field_default_value(
    diagnostic_context& ctx, const t_field& field) {
  if (field.get_default_value() != nullptr) {
    check_const_rec(ctx, field, &field.type().deref(), field.default_value());
  }
}

void validate_field_name(diagnostic_context& ctx, const t_field& field) {
  const auto* strct = dynamic_cast<const t_structured*>(ctx.parent());
  if (field.get_name() == strct->get_name()) {
    std::string parent_structure;
    if (strct->is_union()) {
      parent_structure = "union";
    } else if (strct->is_exception()) {
      parent_structure = "exception";
    } else {
      parent_structure = "struct";
    }
    ctx.warning(
        "Field '{}' has the same name as the containing {}.",
        field.get_name(),
        parent_structure);
  }
}

void validate_structured_annotation(
    diagnostic_context& ctx, const t_named& node) {
  std::unordered_map<const t_type*, const t_const*> seen;
  for (const t_const& annot : node.structured_annotations()) {
    auto [it, inserted] = seen.emplace(annot.type(), &annot);
    if (!inserted) {
      report_redef_error(
          ctx,
          "Structured annotation",
          it->first->name(),
          node,
          annot,
          *it->second);
    }
    validate_const_type_and_value(ctx, annot);
  }
}

void validate_uri_uniqueness(diagnostic_context& ctx, const t_program& prog) {
  // TODO: use string_view as map key
  std::unordered_map<std::string, const t_named*> uri_to_node;
  basic_ast_visitor<true> visit;
  visit.add_definition_visitor([&](const t_named& node) {
    const auto& uri = node.uri();
    if (uri.empty() || uri == kTransitiveUri) {
      return;
    }
    auto result = uri_to_node.emplace(uri, &node);
    if (!result.second) {
      report_redef_error(
          ctx, "Thrift URI", uri, node, node, *result.first->second);
    }
  });
  for (const auto* p : prog.get_included_programs()) {
    visit(*p);
  }
  visit(prog);
}

void limit_terse_write_on_experimental_mode(
    diagnostic_context& ctx, const t_named& node) {
  ctx.check(
      !node.find_structured_annotation_or_null(kTerseWriteUri) ||
          has_experimental_annotation(ctx, node),
      "Using @thrift.TerseWrite on field `{}` is only allowed in the experimental mode.",
      node.name());
}

void validate_field_id(diagnostic_context& ctx, const t_field& node) {
  if (node.explicit_id() != node.id()) {
    ctx.warning(
        node,
        "No field id specified for `{}`, resulting protocol may have conflicts "
        "or not be backwards compatible!",
        node.name());
  }

  ctx.check(
      node.id() != 0 ||
          node.has_annotation("cpp.deprecated_allow_zero_as_field_id"),
      "Zero value (0) not allowed as a field id for `{}`",
      node.get_name());

  ctx.check(
      node.id() >= t_field::min_id || node.is_injected(),
      "Reserved field id ({}) cannot be used for `{}`.",
      node.id(),
      node.name());
}

void validate_compatibility_with_lazy_field(
    diagnostic_context& ctx, const t_structured& node) {
  if (has_lazy_field(node) && node.has_annotation("cpp.methods")) {
    ctx.error(
        "cpp.methods is incompatible with lazy deserialization in struct `{}`",
        node.get_name());
  }
}

void validate_ref_annotation(diagnostic_context& ctx, const t_field& node) {
  if (node.find_structured_annotation_or_null(kCppRefUri) &&
      node.has_annotation(
          {"cpp.ref", "cpp2.ref", "cpp.ref_type", "cpp2.ref_type"})) {
    ctx.error(
        "The @cpp.Ref annotation cannot be combined with the `cpp.ref` or "
        "`cpp.ref_type` annotations. Remove one of the annotations from `{}`.",
        node.name());
  }
}

void validate_cpp_adapter_annotation(
    diagnostic_context& ctx, const t_named& node) {
  adapter_or_wrapper_checker(ctx).check(
      node, kCppAdapterUri, "@cpp.Adapter", "name");
}

void validate_hack_adapter_annotation(
    diagnostic_context& ctx, const t_named& node) {
  adapter_or_wrapper_checker(ctx).check(
      node, kHackAdapterUri, "@hack.Adapter", "name");
}

void validate_hack_wrapper_annotation(
    diagnostic_context& ctx, const t_named& node) {
  adapter_or_wrapper_checker(ctx).check(
      node, kHackWrapperUri, "@hack.Wrapper", "name");
}
// Do not adapt a wrapped type
void validate_hack_wrapper_and_adapter_annotation(
    diagnostic_context& ctx, const t_named& node) {
  adapter_or_wrapper_checker(ctx).check(
      node, kHackAdapterUri, kHackWrapperUri, "@hack.Adapter", "@hack.Wrapper");
}

void validate_java_adapter_annotation(
    diagnostic_context& ctx, const t_named& node) {
  adapter_or_wrapper_checker(ctx).check(
      node, kJavaAdapterUri, "@java.Adapter", "adapterClassName");
}

void validate_java_wrapper_annotation(
    diagnostic_context& ctx, const t_named& node) {
  adapter_or_wrapper_checker(ctx).check(
      node, kJavaWrapperUri, "@java.Wrapper", "wrapperClassName");
}

void validate_java_wrapper_and_adapter_annotation(
    diagnostic_context& ctx, const t_named& node) {
  adapter_or_wrapper_checker(ctx).check(
      node, kJavaAdapterUri, kJavaWrapperUri, "@java.Adapter", "@java.Wrapper");
}

void validate_ref_unique_and_box_annotation(
    diagnostic_context& ctx, const t_field& node) {
  const t_const* adapter_annotation =
      node.find_structured_annotation_or_null(kCppAdapterUri);

  if (cpp2::is_unique_ref(&node)) {
    if (node.has_annotation({"cpp.ref", "cpp2.ref"})) {
      if (adapter_annotation) {
        ctx.error(
            "cpp.ref, cpp2.ref are deprecated. Please use @thrift.Box "
            "annotation instead in `{}` with @cpp.Adapter.",
            node.name());
      } else if (node.qualifier() == t_field_qualifier::optional) {
        ctx.warning(
            "cpp.ref, cpp2.ref are deprecated. Please use @thrift.Box "
            "annotation instead in `{}`.",
            node.name());
      }
    }
    if (node.has_annotation({"cpp.ref_type", "cpp2.ref_type"})) {
      if (adapter_annotation) {
        ctx.error(
            "cpp.ref_type = `unique`, cpp2.ref_type = `unique` are deprecated. "
            "Please use @thrift.Box annotation instead in `{}` with "
            "@cpp.Adapter.",
            node.name());
      } else if (node.qualifier() == t_field_qualifier::optional) {
        ctx.warning(
            "cpp.ref_type = `unique`, cpp2.ref_type = `unique` are deprecated. "
            "Please use @thrift.Box annotation instead in `{}`.",
            node.name());
      }
    }
    if (node.find_structured_annotation_or_null(kCppRefUri) != nullptr) {
      if (adapter_annotation) {
        ctx.error(
            "@cpp.Ref{{type = cpp.RefType.Unique}} is deprecated. Please use "
            "@thrift.Box annotation instead in `{}` with @cpp.Adapter.",
            node.name());
      } else if (node.qualifier() == t_field_qualifier::optional) {
        ctx.warning(
            "@cpp.Ref{{type = cpp.RefType.Unique}} is deprecated. Please use "
            "@thrift.Box annotation instead in `{}`.",
            node.name());
      }
    }
  }
}

void validate_function_priority_annotation(
    diagnostic_context& ctx, const t_node& node) {
  if (auto* priority = node.find_annotation_or_null("priority")) {
    const std::string choices[] = {
        "HIGH_IMPORTANT", "HIGH", "IMPORTANT", "NORMAL", "BEST_EFFORT"};
    auto* end = choices + sizeof(choices) / sizeof(choices[0]);
    ctx.check(
        std::find(choices, end, *priority) != end,
        "Bad priority '{}'. Choose one of {}.",
        *priority,
        choices);
  }
}

void validate_exception_message_annotation(
    diagnostic_context& ctx, const t_exception& node) {
  // Check that value of "message" annotation is
  // - a valid member of struct
  // - of type STRING
  const t_field* field = nullptr;
  for (const auto& f : node.fields()) {
    if (f.find_structured_annotation_or_null(kExceptionMessageUri)) {
      ctx.check(!field, f, "Duplicate message annotation.");
      field = &f;
    }
  }
  if (node.has_annotation("message")) {
    ctx.check(!field, "Duplicate message annotation.");
    const std::string& v = node.get_annotation("message");
    field = node.get_field_by_name(v);
    ctx.check(
        field,
        "member specified as exception 'message' should be a valid "
        "struct member, '{}' in '{}' is not",
        v,
        node.name());
  }
  if (field) {
    ctx.check(
        field->get_type()->is_string_or_binary(),
        "member specified as exception 'message' should be of type "
        "STRING, '{}' in '{}' is not",
        field->name(),
        node.name());

    if (field->name() != "message" && node.get_field_by_name("message")) {
      ctx.warning(
          "Some generators (e.g. PHP) will ignore annotation 'message' as it is "
          "also used as field");
    }
  }
}

void validate_interaction_nesting(
    diagnostic_context& ctx, const t_interaction& node) {
  for (auto* func : node.get_functions()) {
    if (func->interaction()) {
      ctx.error(*func, "Nested interactions are forbidden: {}", func->name());
    }
  }
}

void validate_interaction_annotations(
    diagnostic_context& ctx, const t_interaction& node) {
  for (auto* func : node.get_functions()) {
    ctx.check(
        !func->has_annotation("thread") &&
            !func->find_structured_annotation_or_null(kCppProcessInEbThreadUri),
        "Interaction methods cannot be individually annotated with "
        "thread='eb'. Use process_in_event_base on the interaction instead.");
  }
  if (node.has_annotation("process_in_event_base") ||
      node.find_structured_annotation_or_null(kCppProcessInEbThreadUri)) {
    ctx.check(
        !node.has_annotation("serial") &&
            !node.find_structured_annotation_or_null(kSerialUri),
        "EB interactions are already serial");
  }
}

void validate_cpp_field_interceptor_annotation(
    diagnostic_context& ctx, const t_field& field) {
  if (const t_const* annot =
          field.find_structured_annotation_or_null(kCppFieldInterceptorUri)) {
    try {
      annot->get_value_from_structured_annotation("name");
    } catch (const std::exception&) {
      ctx.error(
          "`@cpp.FieldInterceptor` cannot be used without `name` specified in `{}`.",
          field.name());
      return;
    }
  }
}

void validate_cpp_enum_type(diagnostic_context& ctx, const t_enum& e) {
  if (const t_const* annot =
          e.find_structured_annotation_or_null(kCppEnumTypeUri)) {
    try {
      annot->get_value_from_structured_annotation("type");
    } catch (const std::exception&) {
      ctx.error(
          "`@cpp.EnumType` cannot be used without `type` specified in `{}`.",
          e.name());
      return;
    }
  }
}

void validate_cpp_field_adapter_annotation(
    diagnostic_context& ctx, const t_field& field) {
  adapter_or_wrapper_checker(ctx).check(
      field,
      kCppAdapterUri,
      "@cpp.Adapter",
      false /* disallow_structured_annotations_on_both_field_and_typedef */);
}

void validate_hack_field_adapter_annotation(
    diagnostic_context& ctx, const t_field& field) {
  adapter_or_wrapper_checker(ctx).check(
      field,
      kHackAdapterUri,
      "@hack.Adapter",
      true /* disallow_structured_annotations_on_both_field_and_typedef */);
}

void validate_java_field_adapter_annotation(
    diagnostic_context& ctx, const t_field& field) {
  adapter_or_wrapper_checker(ctx).check(
      field,
      kJavaAdapterUri,
      "@java.Adapter",
      false /* disallow_structured_annotations_on_both_field_and_typedef */);
}

class reserved_ids_checker {
 public:
  explicit reserved_ids_checker(diagnostic_context& ctx) : ctx_(ctx) {}

  void check(const t_structured& node) {
    auto reserved_ids = get_reserved_ids(node);
    check_out_of_range_ids(node, reserved_ids);
    for (const auto& field : node.fields()) {
      ctx_.check(
          reserved_ids.count(field.id()) == 0,
          "Fields in {} cannot use reserved ids: {}",
          node.name(),
          field.id());
    }
  }

  void check(const t_enum& node) {
    auto reserved_ids = get_reserved_ids(node);
    for (const auto& enum_value : node.values()) {
      ctx_.check(
          reserved_ids.count(enum_value.get_value()) == 0,
          "Enum values in {} cannot use reserved ids: {}",
          node.name(),
          enum_value.get_value());
    }
  }

 private:
  diagnostic_context& ctx_;

  // Gets all the reserved ids annotated on this node. Returns
  // empty set if the annotation is not present.
  std::unordered_set<int32_t> get_reserved_ids(const t_type& node) {
    std::unordered_set<int32_t> reserved_ids;

    auto* annotation = node.find_structured_annotation_or_null(kReserveIdsUri);
    if (annotation == nullptr) {
      return reserved_ids;
    }

    // Take the union of the list of tag values in `ids` and the range of
    // of values from `id_ranges`
    if (auto ids =
            annotation->get_value_from_structured_annotation_or_null("ids");
        ids != nullptr) {
      ctx_.check(
          ids->kind() == t_const_value::t_const_value_kind::CV_LIST,
          "Field ids must be a list of integers, annotated on {}",
          node.name());
      for (const auto* id : ids->get_list_or_empty_map()) {
        ctx_.check(
            id->kind() == t_const_value::t_const_value_kind::CV_INTEGER,
            "Field ids must be a list of integers, annotated on {}",
            node.name());
        reserved_ids.insert(id->get_integer());
      }
    }
    if (auto id_ranges =
            annotation->get_value_from_structured_annotation_or_null(
                "id_ranges");
        id_ranges != nullptr) {
      ctx_.check(
          id_ranges->kind() == t_const_value::t_const_value_kind::CV_MAP,
          "Field id_ranges must be a map of integer to integer, annotated on {}",
          node.name());
      for (const auto& [id_range_begin, id_range_end] : id_ranges->get_map()) {
        ctx_.check(
            id_range_begin->kind() ==
                    t_const_value::t_const_value_kind::CV_INTEGER &&
                id_range_begin->kind() ==
                    t_const_value::t_const_value_kind::CV_INTEGER,
            "Field id_ranges must be a map of integer to integer, annotated on {}",
            node.name());
        ctx_.check(
            id_range_begin->get_integer() < id_range_end->get_integer(),
            "For each (start: end) in id_ranges, we must have start < end. Got ({}: {}), annotated on {}",
            id_range_begin->get_integer(),
            id_range_end->get_integer(),
            node.name());
        for (int i = id_range_begin->get_integer();
             i < id_range_end->get_integer();
             ++i) {
          reserved_ids.insert(i);
        }
      }
    }
    return reserved_ids;
  }

  void check_out_of_range_ids(
      const t_structured& node,
      const std::unordered_set<int32_t>& reserved_ids) {
    // Insert into std::set to make sure error message is deterministic
    std::set<int32_t> out_of_range_ids;
    for (auto id : reserved_ids) {
      if (id < std::numeric_limits<std::int16_t>::min() ||
          std::numeric_limits<std::int16_t>::max() < id) {
        out_of_range_ids.insert(id);
      }
    }
    for (auto id : out_of_range_ids) {
      ctx_.error(
          "Struct `{}` cannot have reserved id that is out of range: {}",
          node.name(),
          id);
    }
  }
};

void validate_reserved_ids_structured(
    diagnostic_context& ctx, const t_structured& node) {
  reserved_ids_checker(ctx).check(node);
}

void validate_reserved_ids_enum(diagnostic_context& ctx, const t_enum& node) {
  reserved_ids_checker(ctx).check(node);
}

bool owns_annotations(const t_type* type) {
  if (type->annotations().empty()) {
    return false;
  }
  if (dynamic_cast<const t_container*>(type)) {
    return true;
  }
  if (dynamic_cast<const t_primitive_type*>(type)) {
    return true;
  }
  if (auto t = dynamic_cast<const t_typedef*>(type)) {
    return t->typedef_kind() != t_typedef::kind::defined;
  }
  return false;
}
bool owns_annotations(t_type_ref type) {
  return owns_annotations(type.get_type());
}

void validate_custom_cpp_type_annotations(
    diagnostic_context& ctx, const t_named& node) {
  const bool hasAdapter =
      node.find_structured_annotation_or_null(kCppAdapterUri);
  bool hasCppType = node.has_annotation(
      {"cpp.type", "cpp2.type", "cpp.template", "cpp2.template"});
  const bool hasStructuredCppType =
      node.find_structured_annotation_or_null(kCppTypeUri);

  ctx.check(
      !(hasCppType && hasAdapter),
      "Definition `{}` cannot have both cpp.type/cpp.template and @cpp.Adapter annotations",
      node.name());

  // Excludes annotations that result from annotation lowering.
  auto has_real_annotation = [](const auto& node) {
    if (!owns_annotations(node.type())) {
      return false;
    }
    std::set<std::string> names{
        "cpp.type", "cpp2.type", "cpp.template", "cpp2.template"};
    for (const auto& [k, v] : node.type().get_type()->annotations()) {
      if (names.count(k) && v.src_range.begin != source_location{}) {
        return true;
      }
    }
    return false;
  };

  bool hasUnnamedCppType = false;
  if (auto f = dynamic_cast<const t_field*>(&node)) {
    if (has_real_annotation(*f)) {
      hasUnnamedCppType = true;
    }
  } else if (auto t = dynamic_cast<const t_typedef*>(&node)) {
    if (t->typedef_kind() == t_typedef::kind::defined &&
        has_real_annotation(*t)) {
      hasUnnamedCppType = true;
    }
  }
  if (hasUnnamedCppType) {
    ctx.warning(
        "The cpp.type/cpp.template annotations are deprecated, use @cpp.Type instead");
  }
  if (hasAdapter && (hasUnnamedCppType || hasStructuredCppType)) {
    // TODO (T169470476): make this an error
    ctx.warning(
        "At most one of @cpp.Type/@cpp.Adapter/cpp.type/cpp.template can be specified on a definition.");
  }
  ctx.check(
      hasCppType + hasStructuredCppType + hasUnnamedCppType <= 1,
      "Duplicate cpp.Type annotation");
}

template <typename Node>
void validate_cpp_type_annotation(diagnostic_context& ctx, const Node& node) {
  if (const t_const* annot =
          node.find_structured_annotation_or_null(kCppTypeUri)) {
    auto type = annot->get_value_from_structured_annotation_or_null("name");
    auto tmplate =
        annot->get_value_from_structured_annotation_or_null("template");
    if (!type == !tmplate) {
      ctx.error(
          "Exactly one of `name` and `template` must be specified for `@cpp.Type` on `{}`.",
          node.name());
    }
    if (tmplate) {
      if (!node.type()->get_true_type()->is_container()) {
        ctx.error(
            "`@cpp.Type{{template=...}}` can only be used on containers, not on `{}`.",
            node.name());
      }
    }
  }
}

struct ValidateAnnotationPositions {
  void operator()(diagnostic_context& ctx, const t_const& node) {
    if (owns_annotations(node.type())) {
      err(ctx);
    }
  }
  void operator()(diagnostic_context& ctx, const t_function& node) {
    if (owns_annotations(node.return_type())) {
      err(ctx);
    }
    if (const auto* s = node.sink()) {
      if (owns_annotations(s->elem_type()) ||
          owns_annotations(s->final_response_type())) {
        err(ctx);
      }
    }
    if (const auto* s = node.stream()) {
      if (owns_annotations(s->elem_type())) {
        err(ctx);
      }
    }

    for (auto& field : node.params().fields()) {
      auto type = field.type();
      if (owns_annotations(type)) {
        err(ctx);
      }
    }
  }
  void operator()(diagnostic_context& ctx, const t_container& type) {
    switch (type.get_type_value()) {
      case t_type::type::t_list:
        if (owns_annotations(static_cast<const t_list&>(type).elem_type())) {
          err(ctx);
        }
        break;
      case t_type::type::t_set:
        if (owns_annotations(static_cast<const t_set&>(type).elem_type())) {
          err(ctx);
        }
        break;
      case t_type::type::t_map: {
        const auto& t = static_cast<const t_map&>(type);
        if (owns_annotations(t.key_type()) || owns_annotations(t.val_type())) {
          err(ctx);
        }
        break;
      }
      default:
        assert(false && "Unknown container type");
    }
  }

 private:
  static void err(diagnostic_context& ctx) {
    ctx.error(
        "Annotations are not allowed in this position. Extract the type into a named typedef instead.");
  }
};

void deprecate_annotations(diagnostic_context& ctx, const t_named& node) {
  auto erlang = [](std::string_view name) {
    return fmt::format("facebook.com/thrift/annotation/erlang/{}", name);
  };
  // cpp[2].ref[_type] are handled in dedicated validators.
  static std::map<std::string, std::string> deprecations = {
      {"cpp.type", kCppTypeUri},
      {"cpp2.type", kCppTypeUri},
      {"cpp.template", kCppTypeUri},
      {"cpp2.template", kCppTypeUri},
      {"cpp.box", kBoxUri},
      {"thrift.box", kBoxUri},
      {"hack.attributes", kHackAttributeUri},
      {"py3.hidden", kPythonPy3HiddenUri},
      {"py3.name", kPythonNameUri},
      {"py3.flags", kPythonFlagsUri},
      {"java.switch.mutable", kJavaMutableUri},
      {"java.swift.annotations", kJavaAnnotationUri},
      {"go.name", kGoNameUri},
      {"go.tag", kGoTagUri},
      {"cpp.coroutine", "Nothing, it's on by default"},
      {"cpp.name", kCppNameUri},
      {"code", "Nothing, it is a no-op"},
      {"message", kExceptionMessageUri},
      {"cpp.minimize_padding", kCppMinimizePaddingUri},
      {"cpp.enum_type", kCppEnumTypeUri},
      {"cpp2.enum_type", kCppEnumTypeUri},
      {"cpp.experimental.lazy", kCppLazyUri},
      {"cpp.mixin", kMixinUri},
      {"bitmask", kBitmaskEnumUri},
      {"cpp.declare_bitwise_ops", kBitmaskEnumUri},
      {"cpp2.declare_bitwise_ops", kBitmaskEnumUri},
      {"thread", kCppProcessInEbThreadUri},
      {"process_in_event_base", kCppProcessInEbThreadUri},
      {"hack.name", kHackNameUri},
      {"thrift.uri", kUriUri},
      {"serial", kSerialUri},
      {"priority", kPriorityUri},
      {"erl.name", erlang("NameOverride")},
      {"erl.struct_repr", erlang("StructRepr")},
      {"erl.default_value", erlang("DefaultValue")},
      {"iq.node_type", erlang("Iq")},
  };

  for (const auto& [k, v] : node.annotations()) {
    if (deprecations.count(k)) {
      std::vector<std::string> parts;
      boost::split(parts, deprecations.at(k), [](char c) { return c == '/'; });
      std::string replacement;
      if (parts.size() == 1) {
        replacement = parts[0];
      } else if (parts.size() == 4) {
        replacement = fmt::format("@thrift.{}", parts[3]);
      } else {
        assert(parts.size() == 5);
        replacement = fmt::format("@{}.{}", parts[3], parts[4]);
      }

      if (node.find_structured_annotation_or_null(deprecations.at(k).c_str())) {
        ctx.error("Duplicate annotations {} and {}.", k, replacement);
      } else {
        ctx.warning(
            "The annotation {} is deprecated. Please use {} instead.",
            k,
            replacement);
      }
    }
  }
}

template <typename Node>
bool has_cursor_serialization_adapter(const Node& node) {
  try {
    if (auto* adapter = gen::cpp::type_resolver::find_first_adapter(node)) {
      return adapter->find("apache::thrift::CursorSerializationAdapter") !=
          adapter->npos;
    }
  } catch (const std::runtime_error&) {
    // Adapter annotation is malformed, ignore it.
  }
  return false;
}

void validate_cursor_serialization_adapter_on_field(
    diagnostic_context& ctx, const t_field& node) {
  ctx.check(
      !has_cursor_serialization_adapter(node),
      "CursorSerializationAdapter is not supported on fields. Place it on the top-level struct/union instead.");
}

void validate_cursor_serialization_adapter_on_function(
    diagnostic_context& ctx, const t_function& node) {
  if (node.params().fields().size() <= 1) {
    return;
  }
  for (const auto& field : node.params().fields()) {
    ctx.check(
        !has_cursor_serialization_adapter(field),
        field,
        "CursorSerializationAdapter only supports single-argument functions.");
  }
}

void validate_cursor_serialization_adapter_in_container(
    diagnostic_context& ctx, const t_container& node) {
  auto check = [&](const t_type& type) {
    ctx.check(
        !has_cursor_serialization_adapter(type),
        "CursorSerializationAdapter is not supported inside containers.");
  };
  if (auto* list = dynamic_cast<const t_list*>(&node)) {
    check(*list->elem_type());
  } else if (auto* set = dynamic_cast<const t_set*>(&node)) {
    check(*set->elem_type());
  } else if (auto* map = dynamic_cast<const t_map*>(&node)) {
    check(*map->key_type());
    check(*map->val_type());
  }
}

// TODO (T191018859): forbid as field type too
void forbid_exception_as_method_type(
    diagnostic_context& ctx, const t_function& node) {
  ctx.check(
      !node.return_type()->get_true_type()->is_exception(),
      "Exceptions cannot be used as function return types");
  for (const auto& field : node.params().fields()) {
    ctx.check(
        !field.type()->get_true_type()->is_exception(),
        "Exceptions cannot be used as function arguments");
  }
}
void forbid_exception_as_const_type(
    diagnostic_context& ctx, const t_const& node) {
  ctx.check(
      !node.type()->get_true_type()->is_exception(),
      "Exceptions cannot be used as const types");
}

} // namespace

ast_validator standard_validator() {
  ast_validator validator;
  validator.add_definition_visitor(&validate_identifier_name_is_not_reserved);

  validator.add_interface_visitor(&validate_interface_function_name_uniqueness);
  validator.add_interface_visitor(&validate_function_priority_annotation);
  validator.add_service_visitor(
      &validate_extends_service_function_name_uniqueness);
  validator.add_interaction_visitor(&validate_interaction_nesting);
  validator.add_interaction_visitor(&validate_interaction_annotations);
  validator.add_throws_visitor(&validate_throws_exceptions);
  validator.add_function_visitor(&validate_function_priority_annotation);
  validator.add_function_visitor(ValidateAnnotationPositions{});

  validator.add_structured_definition_visitor(&validate_field_names_uniqueness);
  validator.add_structured_definition_visitor(
      &validate_compatibility_with_lazy_field);
  validator.add_structured_definition_visitor(
      &validate_reserved_ids_structured);
  validator.add_structured_definition_visitor(
      &validate_exception_message_annotation_is_only_in_exceptions);

  validator.add_union_visitor(&validate_union_field_attributes);
  validator.add_exception_visitor(&validate_exception_message_annotation);
  validator.add_field_visitor(&validate_field_id);
  validator.add_field_visitor(&validate_mixin_field_attributes);
  validator.add_field_visitor(&validate_boxed_field_attributes);
  validator.add_field_visitor(&validate_field_default_value);
  validator.add_field_visitor(&validate_ref_annotation);
  validator.add_field_visitor(&validate_ref_unique_and_box_annotation);
  validator.add_field_visitor(&validate_cpp_field_adapter_annotation);
  validator.add_field_visitor(&validate_hack_field_adapter_annotation);
  validator.add_field_visitor(&validate_java_field_adapter_annotation);
  validator.add_field_visitor(&validate_cpp_field_interceptor_annotation);
  validator.add_field_visitor(&validate_required_field);
  validator.add_field_visitor(&validate_cpp_type_annotation<t_field>);
  validator.add_field_visitor(&validate_field_name);

  validator.add_enum_visitor(&validate_enum_value_name_uniqueness);
  validator.add_enum_visitor(&validate_enum_value_uniqueness);
  validator.add_enum_visitor(&validate_reserved_ids_enum);
  validator.add_enum_value_visitor(&validate_enum_value);

  validator.add_definition_visitor(&validate_structured_annotation);
  validator.add_definition_visitor(&validate_annotation_scopes);
  validator.add_definition_visitor(&validate_cpp_adapter_annotation);
  validator.add_definition_visitor(&validate_hack_adapter_annotation);
  validator.add_definition_visitor(&validate_hack_wrapper_annotation);
  validator.add_definition_visitor(
      &validate_hack_wrapper_and_adapter_annotation);
  validator.add_definition_visitor(&validate_java_adapter_annotation);
  validator.add_definition_visitor(&validate_java_wrapper_annotation);
  validator.add_definition_visitor(
      &validate_java_wrapper_and_adapter_annotation);
  validator.add_definition_visitor(&limit_terse_write_on_experimental_mode);
  validator.add_definition_visitor(&validate_custom_cpp_type_annotations);
  validator.add_definition_visitor(&deprecate_annotations);

  validator.add_typedef_visitor(&validate_cpp_type_annotation<t_typedef>);

  validator.add_container_visitor(ValidateAnnotationPositions());
  validator.add_enum_visitor(&validate_cpp_enum_type);
  validator.add_const_visitor(&validate_const_type_and_value);
  validator.add_const_visitor(ValidateAnnotationPositions());
  validator.add_program_visitor(&validate_uri_uniqueness);

  validator.add_field_visitor(&validate_cursor_serialization_adapter_on_field);
  validator.add_function_visitor(
      &validate_cursor_serialization_adapter_on_function);
  validator.add_container_visitor(
      &validate_cursor_serialization_adapter_in_container);
  validator.add_function_visitor(&forbid_exception_as_method_type);
  validator.add_const_visitor(&forbid_exception_as_const_type);

  add_explicit_include_validators(validator);

  return validator;
}

} // namespace compiler
} // namespace thrift
} // namespace apache