#include "libutil/config.hh"

#include <string>
#include <utility>
#include <vector>

#include <absl/strings/numbers.h>
#include <absl/strings/str_split.h>
#include <absl/strings/string_view.h>
#include <glog/logging.h>

#include "libutil/args.hh"
#include "libutil/json.hh"

namespace nix {

bool Config::set(const std::string& name, const std::string& value) {
  auto i = _settings.find(name);
  if (i == _settings.end()) {
    return false;
  }
  i->second.setting->set(value);
  i->second.setting->overriden = true;
  return true;
}

void Config::addSetting(AbstractSetting* setting) {
  _settings.emplace(setting->name, Config::SettingData(false, setting));
  for (auto& alias : setting->aliases) {
    _settings.emplace(alias, Config::SettingData(true, setting));
  }

  bool set = false;

  auto i = unknownSettings.find(setting->name);
  if (i != unknownSettings.end()) {
    setting->set(i->second);
    setting->overriden = true;
    unknownSettings.erase(i);
    set = true;
  }

  for (auto& alias : setting->aliases) {
    auto i = unknownSettings.find(alias);
    if (i != unknownSettings.end()) {
      if (set) {
        LOG(WARNING) << "setting '" << alias
                     << "' is set, but it's an alias of '" << setting->name
                     << "', which is also set";
      }

      else {
        setting->set(i->second);
        setting->overriden = true;
        unknownSettings.erase(i);
        set = true;
      }
    }
  }
}

void AbstractConfig::warnUnknownSettings() {
  for (auto& s : unknownSettings) {
    LOG(WARNING) << "unknown setting: " << s.first;
  }
}

void AbstractConfig::reapplyUnknownSettings() {
  auto unknownSettings2 = std::move(unknownSettings);
  for (auto& s : unknownSettings2) {
    set(s.first, s.second);
  }
}

void Config::getSettings(std::map<std::string, SettingInfo>& res,
                         bool overridenOnly) {
  for (auto& opt : _settings) {
    if (!opt.second.isAlias &&
        (!overridenOnly || opt.second.setting->overriden)) {
      res.emplace(opt.first, SettingInfo{opt.second.setting->to_string(),
                                         opt.second.setting->description});
    }
  }
}

void AbstractConfig::applyConfigFile(const Path& path) {
  try {
    std::string contents = readFile(path);

    unsigned int pos = 0;

    while (pos < contents.size()) {
      std::string line;
      while (pos < contents.size() && contents[pos] != '\n') {
        line += contents[pos++];
      }
      pos++;

      std::string::size_type hash = line.find('#');
      if (hash != std::string::npos) {
        line = std::string(line, 0, hash);
      }

      // TODO(tazjin): absl::string_view after path functions are fixed.
      std::vector<std::string> tokens =
          absl::StrSplit(line, absl::ByAnyChar(" \t\n\r"));
      if (tokens.empty()) {
        continue;
      }

      if (tokens.size() < 2) {
        throw UsageError("illegal configuration line '%1%' in '%2%'", line,
                         path);
      }

      auto include = false;
      auto ignoreMissing = false;
      if (tokens[0] == "include") {
        include = true;
      } else if (tokens[0] == "!include") {
        include = true;
        ignoreMissing = true;
      }

      if (include) {
        if (tokens.size() != 2) {
          throw UsageError("illegal configuration line '%1%' in '%2%'", line,
                           path);
        }
        auto p = absPath(tokens[1], dirOf(path));
        if (pathExists(p)) {
          applyConfigFile(p);
        } else if (!ignoreMissing) {
          throw Error("file '%1%' included from '%2%' not found", p, path);
        }
        continue;
      }

      if (tokens[1] != "=") {
        throw UsageError("illegal configuration line '%1%' in '%2%'", line,
                         path);
      }

      std::string name = tokens[0];

      auto i = tokens.begin();
      advance(i, 2);

      set(name,
          concatStringsSep(" ", Strings(i, tokens.end())));  // FIXME: slow
    };
  } catch (SysError&) {
  }
}

void Config::resetOverriden() {
  for (auto& s : _settings) {
    s.second.setting->overriden = false;
  }
}

void Config::toJSON(JSONObject& out) {
  for (auto& s : _settings) {
    if (!s.second.isAlias) {
      JSONObject out2(out.object(s.first));
      out2.attr("description", s.second.setting->description);
      JSONPlaceholder out3(out2.placeholder("value"));
      s.second.setting->toJSON(out3);
    }
  }
}

void Config::convertToArgs(Args& args, const std::string& category) {
  for (auto& s : _settings) {
    if (!s.second.isAlias) {
      s.second.setting->convertToArg(args, category);
    }
  }
}

AbstractSetting::AbstractSetting(std::string name, std::string description,
                                 std::set<std::string> aliases)
    : name(std::move(name)),
      description(std::move(description)),
      aliases(std::move(aliases)) {}

void AbstractSetting::toJSON(JSONPlaceholder& out) { out.write(to_string()); }

void AbstractSetting::convertToArg(Args& args, const std::string& category) {}

template <typename T>
void BaseSetting<T>::toJSON(JSONPlaceholder& out) {
  out.write(value);
}

template <typename T>
void BaseSetting<T>::convertToArg(Args& args, const std::string& category) {
  args.mkFlag()
      .longName(name)
      .description(description)
      .arity(1)
      .handler([=](std::vector<std::string> ss) {
        overriden = true;
        set(ss[0]);
      })
      .category(category);
}

template <>
void BaseSetting<std::string>::set(const std::string& str) {
  value = str;
}

template <>
std::string BaseSetting<std::string>::to_string() {
  return value;
}

template <typename T>
void BaseSetting<T>::set(const std::string& str) {
  static_assert(std::is_integral<T>::value, "Integer required.");
  if (!absl::SimpleAtoi(str, &value)) {
    throw UsageError("setting '%s' has invalid value '%s'", name, str);
  }
}

template <typename T>
std::string BaseSetting<T>::to_string() {
  static_assert(std::is_integral<T>::value, "Integer required.");
  return std::to_string(value);
}

template <>
void BaseSetting<bool>::set(const std::string& str) {
  if (str == "true" || str == "yes" || str == "1") {
    value = true;
  } else if (str == "false" || str == "no" || str == "0") {
    value = false;
  } else {
    throw UsageError("Boolean setting '%s' has invalid value '%s'", name, str);
  }
}

template <>
std::string BaseSetting<bool>::to_string() {
  return value ? "true" : "false";
}

template <>
void BaseSetting<bool>::convertToArg(Args& args, const std::string& category) {
  args.mkFlag()
      .longName(name)
      .description(description)
      .handler([=](const std::vector<std::string>& ss) { override(true); })
      .category(category);
  args.mkFlag()
      .longName("no-" + name)
      .description(description)
      .handler([=](const std::vector<std::string>& ss) { override(false); })
      .category(category);
}

template <>
void BaseSetting<Strings>::set(const std::string& str) {
  value = absl::StrSplit(str, absl::ByAnyChar(" \t\n\r"));
}

template <>
std::string BaseSetting<Strings>::to_string() {
  return concatStringsSep(" ", value);
}

template <>
void BaseSetting<Strings>::toJSON(JSONPlaceholder& out) {
  JSONList list(out.list());
  for (auto& s : value) {
    list.elem(s);
  }
}

template <>
void BaseSetting<StringSet>::set(const std::string& str) {
  value = absl::StrSplit(str, absl::ByAnyChar(" \t\n\r"));
}

template <>
std::string BaseSetting<StringSet>::to_string() {
  return concatStringsSep(" ", value);
}

template <>
void BaseSetting<StringSet>::toJSON(JSONPlaceholder& out) {
  JSONList list(out.list());
  for (auto& s : value) {
    list.elem(s);
  }
}

template class BaseSetting<int>;
template class BaseSetting<unsigned int>;
template class BaseSetting<long>;
template class BaseSetting<unsigned long>;
template class BaseSetting<long long>;
template class BaseSetting<unsigned long long>;
template class BaseSetting<bool>;
template class BaseSetting<std::string>;
template class BaseSetting<Strings>;
template class BaseSetting<StringSet>;

void PathSetting::set(const std::string& str) {
  if (str.empty()) {
    if (allowEmpty) {
      value = "";
    } else {
      throw UsageError("setting '%s' cannot be empty", name);
    }
  } else {
    value = canonPath(str);
  }
}

bool GlobalConfig::set(const std::string& name, const std::string& value) {
  for (auto& config : *configRegistrations) {
    if (config->set(name, value)) {
      return true;
    }
  }

  unknownSettings.emplace(name, value);

  return false;
}

void GlobalConfig::getSettings(std::map<std::string, SettingInfo>& res,
                               bool overridenOnly) {
  for (auto& config : *configRegistrations) {
    config->getSettings(res, overridenOnly);
  }
}

void GlobalConfig::resetOverriden() {
  for (auto& config : *configRegistrations) {
    config->resetOverriden();
  }
}

void GlobalConfig::toJSON(JSONObject& out) {
  for (auto& config : *configRegistrations) {
    config->toJSON(out);
  }
}

void GlobalConfig::convertToArgs(Args& args, const std::string& category) {
  for (auto& config : *configRegistrations) {
    config->convertToArgs(args, category);
  }
}

GlobalConfig globalConfig;

GlobalConfig::ConfigRegistrations* GlobalConfig::configRegistrations;

GlobalConfig::Register::Register(Config* config) {
  if (configRegistrations == nullptr) {
    configRegistrations = new ConfigRegistrations;
  }
  configRegistrations->emplace_back(config);
}

}  // namespace nix