#include "libmain/common-args.hh"
#include "libmain/shared.hh"
#include "libstore/store-api.hh"
#include "nix/command.hh"

using namespace nix;

struct CmdBuild final : MixDryRun, InstallablesCommand {
  Path outLink = "result";

  CmdBuild() {
    mkFlag()
        .longName("out-link")
        .shortName('o')
        .description("path of the symlink to the build result")
        .labels({"path"})
        .dest(&outLink);

    mkFlag()
        .longName("no-link")
        .description("do not create a symlink to the build result")
        .set(&outLink, Path(""));
  }

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

  std::string description() override {
    return "build a derivation or fetch a store path";
  }

  Examples examples() override {
    return {
        Example{"To build and run GNU Hello from NixOS 17.03:",
                "nix build -f channel:nixos-17.03 hello; ./result/bin/hello"},
        Example{"To build the build.x86_64-linux attribute from release.nix:",
                "nix build -f release.nix build.x86_64-linux"},
    };
  }

  void run(ref<Store> store) override {
    auto buildables = build(store, dryRun ? DryRun : Build, installables);

    if (dryRun) {
      return;
    }

    for (size_t i = 0; i < buildables.size(); ++i) {
      auto& b(buildables[i]);

      if (!outLink.empty()) {
        for (auto& output : b.outputs) {
          if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>()) {
            std::string symlink = outLink;
            if (i != 0u) {
              symlink += fmt("-%d", i);
            }
            if (output.first != "out") {
              symlink += fmt("-%s", output.first);
            }
            store2->addPermRoot(output.second, absPath(symlink), true);
          }
        }
      }
    }
  }
};

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