#include <absl/strings/match.h>
#include <absl/strings/str_cat.h>
#include <absl/strings/str_split.h>

#include "libmain/shared.hh"
#include "libstore/serve-protocol.hh"
#include "libstore/store-api.hh"
#include "libstore/worker-protocol.hh"
#include "nix/command.hh"

using namespace nix;

std::string formatProtocol(unsigned int proto) {
  if (proto != 0u) {
    auto major = GET_PROTOCOL_MAJOR(proto) >> 8;
    auto minor = GET_PROTOCOL_MINOR(proto);
    return (format("%1%.%2%") % major % minor).str();
  }
  return "unknown";
}

struct CmdDoctor : StoreCommand {
  bool success = true;

  std::string name() override { return "doctor"; }

  std::string description() override {
    return "check your system for potential problems";
  }

  void run(ref<Store> store) override {
    std::cout << "Store uri: " << store->getUri() << std::endl;
    std::cout << std::endl;

    auto type = getStoreType();

    if (type < tOther) {
      success &= checkNixInPath();
      success &= checkProfileRoots(store);
    }
    success &= checkStoreProtocol(store->getProtocol());

    if (!success) {
      throw Exit(2);
    }
  }

  static bool checkNixInPath() {
    PathSet dirs;

    for (auto& dir : absl::StrSplit(getEnv("PATH"), absl::ByChar(':'))) {
      if (pathExists(absl::StrCat(dir, "/nix-env"))) {
        dirs.insert(dirOf(canonPath(absl::StrCat(dir, "/nix-env"), true)));
      }
    }

    if (dirs.size() != 1) {
      std::cout << "Warning: multiple versions of nix found in PATH."
                << std::endl;
      std::cout << std::endl;
      for (auto& dir : dirs) {
        std::cout << "  " << dir << std::endl;
      }
      std::cout << std::endl;
      return false;
    }

    return true;
  }

  static bool checkProfileRoots(const ref<Store>& store) {
    PathSet dirs;

    for (auto dir : absl::StrSplit(getEnv("PATH"), absl::ByChar(':'))) {
      Path profileDir = dirOf(dir);
      try {
        Path userEnv = canonPath(profileDir, true);

        if (store->isStorePath(userEnv) &&
            absl::EndsWith(userEnv, "user-environment")) {
          while (profileDir.find("/profiles/") == std::string::npos &&
                 isLink(profileDir)) {
            profileDir = absPath(readLink(profileDir), dirOf(profileDir));
          }

          if (profileDir.find("/profiles/") == std::string::npos) {
            dirs.insert(std::string(dir));
          }
        }
      } catch (SysError&) {
      }
    }

    if (!dirs.empty()) {
      std::cout << "Warning: found profiles outside of " << settings.nixStateDir
                << "/profiles." << std::endl;
      std::cout << "The generation this profile points to might not have a "
                   "gcroot and could be"
                << std::endl;
      std::cout << "garbage collected, resulting in broken symlinks."
                << std::endl;
      std::cout << std::endl;
      for (auto& dir : dirs) {
        std::cout << "  " << dir << std::endl;
      }
      std::cout << std::endl;
      return false;
    }

    return true;
  }

  static bool checkStoreProtocol(unsigned int storeProto) {
    unsigned int clientProto = GET_PROTOCOL_MAJOR(SERVE_PROTOCOL_VERSION) ==
                                       GET_PROTOCOL_MAJOR(storeProto)
                                   ? SERVE_PROTOCOL_VERSION
                                   : PROTOCOL_VERSION;

    if (clientProto != storeProto) {
      std::cout << "Warning: protocol version of this client does not match "
                   "the store."
                << std::endl;
      std::cout << "While this is not necessarily a problem it's recommended "
                   "to keep the client in"
                << std::endl;
      std::cout << "sync with the daemon." << std::endl;
      std::cout << std::endl;
      std::cout << "Client protocol: " << formatProtocol(clientProto)
                << std::endl;
      std::cout << "Store protocol: " << formatProtocol(storeProto)
                << std::endl;
      std::cout << std::endl;
      return false;
    }

    return true;
  }
};

static RegisterCommand r1(make_ref<CmdDoctor>());