// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "extensions/renderer/argument_spec.h"

#include "base/memory/ptr_util.h"
#include "base/values.h"
#include "content/public/child/v8_value_converter.h"
#include "extensions/renderer/api_type_reference_map.h"
#include "gin/converter.h"
#include "gin/dictionary.h"

namespace extensions {

namespace {

template <class T>
bool ParseFundamentalValueHelper(v8::Local<v8::Value> arg,
                                 v8::Local<v8::Context> context,
                                 const base::Optional<int>& minimum,
                                 std::unique_ptr<base::Value>* out_value) {
  T val;
  if (!gin::Converter<T>::FromV8(context->GetIsolate(), arg, &val))
    return false;
  if (minimum && val < minimum.value())
    return false;
  if (out_value)
    *out_value = base::MakeUnique<base::Value>(val);
  return true;
}

}  // namespace

ArgumentSpec::ArgumentSpec(const base::Value& value)
    : type_(ArgumentType::INTEGER), optional_(false) {
  const base::DictionaryValue* dict = nullptr;
  CHECK(value.GetAsDictionary(&dict));
  dict->GetBoolean("optional", &optional_);
  dict->GetString("name", &name_);

  InitializeType(dict);
}

void ArgumentSpec::InitializeType(const base::DictionaryValue* dict) {
  std::string ref_string;
  if (dict->GetString("$ref", &ref_string)) {
    ref_ = std::move(ref_string);
    type_ = ArgumentType::REF;
    return;
  }

  {
    const base::ListValue* choices = nullptr;
    if (dict->GetList("choices", &choices)) {
      DCHECK(!choices->empty());
      type_ = ArgumentType::CHOICES;
      choices_.reserve(choices->GetSize());
      for (const auto& choice : *choices)
        choices_.push_back(base::MakeUnique<ArgumentSpec>(*choice));
      return;
    }
  }

  std::string type_string;
  CHECK(dict->GetString("type", &type_string));
  if (type_string == "integer")
    type_ = ArgumentType::INTEGER;
  else if (type_string == "number")
    type_ = ArgumentType::DOUBLE;
  else if (type_string == "object")
    type_ = ArgumentType::OBJECT;
  else if (type_string == "array")
    type_ = ArgumentType::LIST;
  else if (type_string == "boolean")
    type_ = ArgumentType::BOOLEAN;
  else if (type_string == "string")
    type_ = ArgumentType::STRING;
  else if (type_string == "binary")
    type_ = ArgumentType::BINARY;
  else if (type_string == "any")
    type_ = ArgumentType::ANY;
  else if (type_string == "function")
    type_ = ArgumentType::FUNCTION;
  else
    NOTREACHED();

  int min = 0;
  if (dict->GetInteger("minimum", &min))
    minimum_ = min;

  if (type_ == ArgumentType::OBJECT) {
    const base::DictionaryValue* properties_value = nullptr;
    if (dict->GetDictionary("properties", &properties_value)) {
      for (base::DictionaryValue::Iterator iter(*properties_value);
           !iter.IsAtEnd(); iter.Advance()) {
        properties_[iter.key()] = base::MakeUnique<ArgumentSpec>(iter.value());
      }
    }
    const base::DictionaryValue* additional_properties_value = nullptr;
    if (dict->GetDictionary("additionalProperties",
                            &additional_properties_value)) {
      additional_properties_ =
          base::MakeUnique<ArgumentSpec>(*additional_properties_value);
    }
  } else if (type_ == ArgumentType::LIST) {
    const base::DictionaryValue* item_value = nullptr;
    CHECK(dict->GetDictionary("items", &item_value));
    list_element_type_ = base::MakeUnique<ArgumentSpec>(*item_value);
  } else if (type_ == ArgumentType::STRING) {
    // Technically, there's no reason enums couldn't be other objects (e.g.
    // numbers), but right now they seem to be exclusively strings. We could
    // always update this if need be.
    const base::ListValue* enums = nullptr;
    if (dict->GetList("enum", &enums)) {
      size_t size = enums->GetSize();
      CHECK_GT(size, 0u);
      for (size_t i = 0; i < size; ++i) {
        std::string enum_value;
        // Enum entries come in two versions: a list of possible strings, and
        // a dictionary with a field 'name'.
        if (!enums->GetString(i, &enum_value)) {
          const base::DictionaryValue* enum_value_dictionary = nullptr;
          CHECK(enums->GetDictionary(i, &enum_value_dictionary));
          CHECK(enum_value_dictionary->GetString("name", &enum_value));
        }
        enum_values_.insert(std::move(enum_value));
      }
    }
  }
}

ArgumentSpec::~ArgumentSpec() {}

bool ArgumentSpec::ParseArgument(v8::Local<v8::Context> context,
                                 v8::Local<v8::Value> value,
                                 const APITypeReferenceMap& refs,
                                 std::unique_ptr<base::Value>* out_value,
                                 std::string* error) const {
  if (type_ == ArgumentType::FUNCTION) {
    // We can't serialize functions. We shouldn't be asked to.
    DCHECK(!out_value);
    return value->IsFunction();
  }

  if (type_ == ArgumentType::REF) {
    DCHECK(ref_);
    const ArgumentSpec* reference = refs.GetSpec(ref_.value());
    DCHECK(reference) << ref_.value();
    return reference->ParseArgument(context, value, refs, out_value, error);
  }

  if (type_ == ArgumentType::CHOICES) {
    for (const auto& choice : choices_) {
      if (choice->ParseArgument(context, value, refs, out_value, error))
        return true;
    }
    *error = "Did not match any of the choices";
    return false;
  }

  if (IsFundamentalType())
    return ParseArgumentToFundamental(context, value, out_value, error);
  if (type_ == ArgumentType::OBJECT) {
    // Don't allow functions or arrays (even though they are technically
    // objects). This is to make it easier to match otherwise-ambiguous
    // signatures. For instance, if an API method has an optional object
    // parameter and then an optional callback, we wouldn't necessarily be able
    // to match the arguments if we allowed functions as objects.
    if (!value->IsObject() || value->IsFunction() || value->IsArray()) {
      *error = "Wrong type";
      return false;
    }
    v8::Local<v8::Object> object = value.As<v8::Object>();
    return ParseArgumentToObject(context, object, refs, out_value, error);
  }
  if (type_ == ArgumentType::LIST) {
    if (!value->IsArray()) {
      *error = "Wrong type";
      return false;
    }
    v8::Local<v8::Array> array = value.As<v8::Array>();
    return ParseArgumentToArray(context, array, refs, out_value, error);
  }
  if (type_ == ArgumentType::BINARY) {
    if (!value->IsArrayBuffer() && !value->IsArrayBufferView()) {
      *error = "Wrong type";
      return false;
    }
    return ParseArgumentToAny(context, value, out_value, error);
  }
  if (type_ == ArgumentType::ANY)
    return ParseArgumentToAny(context, value, out_value, error);
  NOTREACHED();
  return false;
}

bool ArgumentSpec::IsFundamentalType() const {
  return type_ == ArgumentType::INTEGER || type_ == ArgumentType::DOUBLE ||
         type_ == ArgumentType::BOOLEAN || type_ == ArgumentType::STRING;
}

bool ArgumentSpec::ParseArgumentToFundamental(
    v8::Local<v8::Context> context,
    v8::Local<v8::Value> value,
    std::unique_ptr<base::Value>* out_value,
    std::string* error) const {
  DCHECK(IsFundamentalType());
  switch (type_) {
    case ArgumentType::INTEGER:
      return ParseFundamentalValueHelper<int32_t>(value, context, minimum_,
                                                  out_value);
    case ArgumentType::DOUBLE:
      return ParseFundamentalValueHelper<double>(value, context, minimum_,
                                                 out_value);
    case ArgumentType::STRING: {
      if (!value->IsString())
        return false;
      // If we don't need to match enum values and don't need to convert, we're
      // done...
      if (!out_value && enum_values_.empty())
        return true;
      // ...Otherwise, we need to convert to a std::string.
      std::string s;
      // We already checked that this is a string, so this should never fail.
      CHECK(gin::Converter<std::string>::FromV8(context->GetIsolate(), value,
                                                &s));
      if (!enum_values_.empty() && enum_values_.count(s) == 0)
        return false;
      if (out_value) {
        // TODO(devlin): If base::StringValue ever takes a std::string&&, we
        // could use std::move to construct.
        *out_value = base::MakeUnique<base::StringValue>(s);
      }
      return true;
    }
    case ArgumentType::BOOLEAN: {
      if (!value->IsBoolean())
        return false;
      if (out_value) {
        *out_value =
            base::MakeUnique<base::Value>(value.As<v8::Boolean>()->Value());
      }
      return true;
    }
    default:
      NOTREACHED();
  }
  return false;
}

bool ArgumentSpec::ParseArgumentToObject(
    v8::Local<v8::Context> context,
    v8::Local<v8::Object> object,
    const APITypeReferenceMap& refs,
    std::unique_ptr<base::Value>* out_value,
    std::string* error) const {
  DCHECK_EQ(ArgumentType::OBJECT, type_);
  std::unique_ptr<base::DictionaryValue> result;
  // Only construct the result if we have an |out_value| to populate.
  if (out_value)
    result = base::MakeUnique<base::DictionaryValue>();

  gin::Dictionary dictionary(context->GetIsolate(), object);
  for (const auto& kv : properties_) {
    v8::Local<v8::Value> subvalue;
    // See comment in ParseArgumentToArray() about passing in custom crazy
    // values here.
    // TODO(devlin): gin::Dictionary::Get() uses Isolate::GetCurrentContext() -
    // is that always right here, or should we use the v8::Object APIs and
    // pass in |context|?
    // TODO(devlin): Hyper-optimization - Dictionary::Get() also creates a new
    // v8::String for each call. Hypothetically, we could cache these, or at
    // least use an internalized string.
    if (!dictionary.Get(kv.first, &subvalue))
      return false;

    if (subvalue.IsEmpty() || subvalue->IsNull() || subvalue->IsUndefined()) {
      if (!kv.second->optional_) {
        *error = "Missing key: " + kv.first;
        return false;
      }
      continue;
    }
    std::unique_ptr<base::Value> property;
    if (!kv.second->ParseArgument(context, subvalue, refs,
                                  out_value ? &property : nullptr, error)) {
      return false;
    }
    if (result)
      result->Set(kv.first, std::move(property));
  }

  // Check for additional properties.
  if (additional_properties_) {
    v8::Local<v8::Array> own_property_names;
    if (!object->GetOwnPropertyNames(context).ToLocal(&own_property_names))
      return false;
    uint32_t length = own_property_names->Length();
    for (uint32_t i = 0; i < length; ++i) {
      v8::Local<v8::Value> key;
      if (!own_property_names->Get(context, i).ToLocal(&key))
        return false;
      // In JS, all keys are strings or numbers (or symbols, but those are
      // excluded by GetOwnPropertyNames()). If you try to set anything else
      // (e.g. an object), it is converted to a string.
      DCHECK(key->IsString() || key->IsNumber());
      v8::String::Utf8Value utf8_key(key);
      // If the key was one of the specified properties, we've already handled
      // it. Continue.
      if (properties_.find(*utf8_key) != properties_.end())
        continue;
      v8::Local<v8::Value> subvalue;
      // Fun: It's possible that a previous getter has removed the property from
      // the object. This isn't that big of a deal, since it would only manifest
      // in the case of some reasonably-crazy script objects, and it's probably
      // not worth optimizing for the uncommon case to the detriment of the
      // common (and either should be totally safe). We can always add a
      // HasOwnProperty() check here in the future, if we desire.
      if (!object->Get(context, key).ToLocal(&subvalue))
        return false;

      // We don't serialize undefined values.
      // TODO(devlin): This matches current behavior, but it is correct?
      if (subvalue->IsUndefined())
        continue;

      std::unique_ptr<base::Value> property;
      if (!additional_properties_->ParseArgument(
              context, subvalue, refs, result ? &property : nullptr, error)) {
        return false;
      }
      if (result)
        result->SetWithoutPathExpansion(*utf8_key, std::move(property));
    }
  }

  if (out_value)
    *out_value = std::move(result);
  return true;
}

bool ArgumentSpec::ParseArgumentToArray(v8::Local<v8::Context> context,
                                        v8::Local<v8::Array> value,
                                        const APITypeReferenceMap& refs,
                                        std::unique_ptr<base::Value>* out_value,
                                        std::string* error) const {
  DCHECK_EQ(ArgumentType::LIST, type_);
  std::unique_ptr<base::ListValue> result;
  // Only construct the result if we have an |out_value| to populate.
  if (out_value)
    result = base::MakeUnique<base::ListValue>();
  uint32_t length = value->Length();
  for (uint32_t i = 0; i < length; ++i) {
    v8::MaybeLocal<v8::Value> maybe_subvalue = value->Get(context, i);
    v8::Local<v8::Value> subvalue;
    // Note: This can fail in the case of a developer passing in the following:
    // var a = [];
    // Object.defineProperty(a, 0, { get: () => { throw new Error('foo'); } });
    // Currently, this will cause the developer-specified error ('foo') to be
    // thrown.
    // TODO(devlin): This is probably fine, but it's worth contemplating
    // catching the error and throwing our own.
    if (!maybe_subvalue.ToLocal(&subvalue))
      return false;
    std::unique_ptr<base::Value> item;
    if (!list_element_type_->ParseArgument(context, subvalue, refs,
                                           result ? &item : nullptr, error)) {
      return false;
    }
    if (result)
      result->Append(std::move(item));
  }
  if (out_value)
    *out_value = std::move(result);
  return true;
}

bool ArgumentSpec::ParseArgumentToAny(v8::Local<v8::Context> context,
                                      v8::Local<v8::Value> value,
                                      std::unique_ptr<base::Value>* out_value,
                                      std::string* error) const {
  DCHECK(type_ == ArgumentType::ANY || type_ == ArgumentType::BINARY);
  if (out_value) {
    std::unique_ptr<content::V8ValueConverter> converter(
        content::V8ValueConverter::create());
    std::unique_ptr<base::Value> converted(
        converter->FromV8Value(value, context));
    if (!converted) {
      *error = "Could not convert to 'any'.";
      return false;
    }
    if (type_ == ArgumentType::BINARY)
      DCHECK_EQ(base::Value::Type::BINARY, converted->GetType());
    *out_value = std::move(converted);
  }
  return true;
}

}  // namespace extensions