// file      : mod/mod-build-result.cxx -*- C++ -*-
// copyright : Copyright (c) 2014-2018 Code Synthesis Ltd
// license   : MIT; see accompanying LICENSE file

#include <mod/mod-build-result.hxx>

#include <odb/database.hxx>
#include <odb/transaction.hxx>

#include <libbutl/openssl.mxx>
#include <libbutl/sendmail.mxx>
#include <libbutl/fdstream.mxx>
#include <libbutl/process-io.mxx>
#include <libbutl/manifest-parser.mxx>
#include <libbutl/manifest-serializer.mxx>

#include <libbbot/manifest.hxx>

#include <web/module.hxx>

#include <libbrep/build.hxx>
#include <libbrep/build-odb.hxx>
#include <libbrep/package.hxx>
#include <libbrep/package-odb.hxx>

#include <mod/build.hxx>   // *_url()
#include <mod/options.hxx>

using namespace std;
using namespace butl;
using namespace bbot;
using namespace brep::cli;
using namespace odb::core;

// While currently the user-defined copy constructor is not required (we don't
// need to deep copy nullptr's), it is a good idea to keep the placeholder
// ready for less trivial cases.
//
brep::build_result::
build_result (const build_result& r)
    : database_module (r),
      build_config_module (r),
      options_ (r.initialized_ ? r.options_ : nullptr)
{
}

void brep::build_result::
init (scanner& s)
{
  HANDLER_DIAG;

  options_ = make_shared<options::build_result> (
    s, unknown_mode::fail, unknown_mode::fail);

  database_module::init (static_cast<options::package_db> (*options_),
                         options_->package_db_retry ());

  if (options_->build_config_specified ())
  {
    database_module::init (static_cast<options::build_db> (*options_),
                           options_->build_db_retry ());

    build_config_module::init (static_cast<options::build> (*options_));
  }

  if (options_->root ().empty ())
    options_->root (dir_path ("/"));
}

bool brep::build_result::
handle (request& rq, response&)
{
  using brep::version; // Not to confuse with module::version.

  HANDLER_DIAG;

  if (build_db_ == nullptr)
    throw invalid_request (501, "not implemented");

  // Make sure no parameters passed.
  //
  try
  {
    // Note that we expect the result request manifest to be posted and so
    // consider parameters from the URL only.
    //
    name_value_scanner s (rq.parameters (0 /* limit */, true /* url_only */));
    params::build_result (s, unknown_mode::fail, unknown_mode::fail);
  }
  catch (const cli::exception& e)
  {
    throw invalid_request (400, e.what ());
  }

  result_request_manifest rqm;

  try
  {
    // We fully cache the request content to be able to retry the request
    // handling if odb::recoverable is thrown (see database-module.cxx for
    // details).
    //
    size_t limit (options_->build_result_request_max_size ());
    manifest_parser p (rq.content (limit, limit), "result_request_manifest");
    rqm = result_request_manifest (p);
  }
  catch (const manifest_parsing& e)
  {
    throw invalid_request (400, e.what ());
  }

  // Parse the task response session to obtain the build configuration name and
  // the timestamp, and to make sure the session matches tenant and the result
  // manifest's package name, and version.
  //
  build_id id;
  timestamp session_timestamp;

  try
  {
    const string& s (rqm.session);

    size_t p (s.find ('/')); // End of tenant.

    if (p == string::npos)
      throw invalid_argument ("no package name");

    if (tenant.compare (0, tenant.size (), s, 0, p) != 0)
      throw invalid_argument ("tenant mismatch");

    size_t b (p + 1);    // Start of package name.
    p = s.find ('/', b); // End of package name.

    if (p == b)
      throw invalid_argument ("empty package name");

    if (p == string::npos)
      throw invalid_argument ("no package version");

    package_name& name (rqm.result.name);
    {
      const string& n (name.string ());
      if (n.compare (0, n.size (), s, b, p - b) != 0)
        throw invalid_argument ("package name mismatch");
    }

    b = p + 1;           // Start of version.
    p = s.find ('/', b); // End of version.

    if (p == string::npos)
      throw invalid_argument ("no configuration name");

    auto parse_version = [&s, &b, &p] (const char* what) -> version
    {
      // Intercept exception handling to add the parsing error attribution.
      //
      try
      {
        return brep::version (string (s, b, p - b));
      }
      catch (const invalid_argument& e)
      {
        throw invalid_argument (string ("invalid ") + what + ": " + e.what ());
      }
    };

    version package_version (parse_version ("package version"));

    if (package_version != rqm.result.version)
      throw invalid_argument ("package version mismatch");

    b = p + 1;           // Start of configuration name.
    p = s.find ('/', b); // End of configuration name.

    if (p == string::npos)
      throw invalid_argument ("no toolchain version");

    string config (s, b, p - b);

    b = p + 1;           // Start of toolchain version.
    p = s.find ('/', b); // End of toolchain version.

    if (p == string::npos)
      throw invalid_argument ("no timestamp");

    version toolchain_version (parse_version ("toolchain version"));

    id = build_id (package_id (move (tenant), move (name), package_version),
                   move (config),
                   toolchain_version);

    if (id.configuration.empty ())
      throw invalid_argument ("empty configuration name");

    try
    {
      size_t tsn;
      string ts (s, p + 1);

      session_timestamp = timestamp (
        chrono::duration_cast<timestamp::duration> (
          chrono::nanoseconds (stoull (ts, &tsn))));

      if (tsn != ts.size ())
        throw invalid_argument ("trailing junk");
    }
    // Handle invalid_argument or out_of_range (both derive from logic_error),
    // that can be thrown by stoull().
    //
    catch (const logic_error& e)
    {
      throw invalid_argument (string ("invalid timestamp: ") + e.what ());
    }
  }
  catch (const invalid_argument& e)
  {
    throw invalid_request (400, string ("invalid session: ") + e.what ());
  }

  // If the session expired (no such configuration, package, etc), then we log
  // this case with the warning severity and respond with the 200 HTTP code as
  // if the session is valid. The thinking is that this is a problem with the
  // controller's setup (expires too fast), not with the agent's.
  //
  auto warn_expired = [&rqm, &warn] (const string& d)
  {
    warn << "session '" << rqm.session << "' expired: " << d;
  };

  // Make sure the build configuration still exists.
  //
  const bbot::build_config* cfg;
  {
    auto i (build_conf_map_->find (id.configuration.c_str ()));

    if (i == build_conf_map_->end ())
    {
      warn_expired ("no build configuration");
      return true;
    }

    cfg = i->second;
  }

  // Load the built package (if present).
  //
  // The only way not to deal with 2 databases simultaneously is to pull
  // another bunch of the package fields into the build_package foreign
  // object, which is a pain (see build_package.hxx for details). Doesn't seem
  // worth it here: email members are really secondary and we don't need to
  // switch transactions back and forth.
  //
  shared_ptr<package> pkg;
  {
    transaction t (package_db_->begin ());
    pkg = package_db_->find<package> (id.package);
    t.commit ();
  }

  if (pkg == nullptr)
  {
    warn_expired ("no package");
    return true;
  }

  auto print_args = [&trace, this] (const char* args[], size_t n)
  {
    l2 ([&]{trace << process_args {args, n};});
  };

  // Load and update the package build configuration (if present).
  //
  // NULL if the package build doesn't exist or is not updated for any reason
  // (authentication failed, etc) or the configuration is excluded by the
  // package.
  //
  shared_ptr<build> bld;

  optional<result_status> prev_status;
  bool build_notify (false);
  bool unforced (true);

  {
    transaction t (build_db_->begin ());

    package_build pb;
    shared_ptr<build> b;
    if (!build_db_->query_one<package_build> (
          query<package_build>::build::id == id, pb))
      warn_expired ("no package build");
    else if ((b = move (pb.build))->state != build_state::building)
      warn_expired ("package configuration state is " + to_string (b->state));
    else if (b->timestamp != session_timestamp)
      warn_expired ("non-matching timestamp");
    else
    {
      // Check the challenge.
      //
      // If the challenge doesn't match expectations (probably due to the
      // authentication settings change), then we log this case with the
      // warning severity and respond with the 200 HTTP code as if the
      // challenge is valid. The thinking is that we shouldn't alarm a
      // law-abaiding agent and shouldn't provide any information to a
      // malicious one.
      //
      auto warn_auth = [&rqm, &warn] (const string& d)
      {
        warn << "session '" << rqm.session << "' authentication failed: " << d;
      };

      bool auth (false);

      // Must both be present or absent.
      //
      if (!b->agent_challenge != !rqm.challenge)
        warn_auth (rqm.challenge
                   ? "unexpected challenge"
                   : "challenge is expected");
      else if (bot_agent_key_map_ == nullptr) // Authentication is disabled.
        auth = true;
      else if (!b->agent_challenge) // Authentication is recently enabled.
        warn_auth ("challenge is required now");
      else
      {
        assert (b->agent_fingerprint && rqm.challenge);
        auto i (bot_agent_key_map_->find (*b->agent_fingerprint));

        // The agent's key is recently replaced.
        //
        if (i == bot_agent_key_map_->end ())
          warn_auth ("agent's public key not found");
        else
        {
          try
          {
            openssl os (print_args,
                        path ("-"), fdstream_mode::text, 2,
                        process_env (options_->openssl (),
                                     options_->openssl_envvar ()),
                        "rsautl",
                        options_->openssl_option (),
                        "-verify", "-pubin", "-inkey", i->second);

            for (const auto& c: *rqm.challenge)
              os.out.put (c); // Sets badbit on failure.

            os.out.close ();

            string s;
            getline (os.in, s);

            bool v (os.in.eof ());
            os.in.close ();

            if (os.wait () && v)
            {
              auth = s == *b->agent_challenge;

              if (!auth)
                warn_auth ("challenge mismatched");
            }
            else // The signature is presumably meaningless.
              warn_auth ("unable to verify challenge");
          }
          catch (const system_error& e)
          {
            fail << "unable to verify challenge: " << e;
          }
        }
      }

      if (auth)
      {
        unforced = b->force == force_state::unforced;

        // Don't send email to the build-email address for the
        // success-to-success status change, unless the build was forced.
        //
        build_notify = !(rqm.result.status == result_status::success &&
                         b->status                                   &&
                         *b->status == rqm.result.status             &&
                         unforced);

        prev_status = move (b->status);

        b->state  = build_state::built;
        b->status = rqm.result.status;
        b->force  = force_state::unforced;

        // Cleanup the authentication data.
        //
        b->agent_fingerprint = nullopt;
        b->agent_challenge = nullopt;

        // Mark the section as loaded, so results are updated.
        //
        b->results_section.load ();
        b->results = move (rqm.result.results);

        b->timestamp = system_clock::now ();

        build_db_->update (b);

        shared_ptr<build_package> p (
          build_db_->load<build_package> (b->id.package));

        if (belongs (*cfg, "all") &&
            !exclude (p->builds, p->constraints, *cfg))
          bld = move (b);
      }
    }

    t.commit ();
  }

  if (bld == nullptr)
    return true;

  string subj ((unforced ? "build " : "rebuild ") +
               to_string (*bld->status) + ": " +
               bld->package_name.string () + '/' +
               bld->package_version.string () + '/' +
               bld->configuration + '/' +
               bld->toolchain_name + '-' + bld->toolchain_version.string ());

  // Send notification emails to the interested parties.
  //
  auto send_email = [&bld, &subj, &error, &trace, &print_args, this]
                    (const string& to)
  {
    try
    {
      l2 ([&]{trace << "email '" << subj << "' to " << to;});

      // Redirect the diagnostics to webserver error log.
      //
      // Note: if using this somewhere else, then need to factor out all this
      // exit status handling code.
      //
      sendmail sm (print_args,
                   2,
                   options_->email (),
                   subj,
                   {to});

      if (bld->results.empty ())
        sm.out << "No operation results available." << endl;
      else
      {
        const string& host (options_->host ());
        const dir_path& root (options_->root ());

        ostream& os (sm.out);

        assert (bld->status);
        os << "combined: " << *bld->status << endl << endl
           << "  " << build_log_url (host, root, *bld) << endl << endl;

        for (const auto& r: bld->results)
          os << r.operation << ": " << r.status << endl << endl
             << "  " << build_log_url (host, root, *bld, &r.operation)
             << endl << endl;

        os << "Force rebuild (enter the reason, use '+' instead of spaces):"
           << endl << endl
           << "  " << build_force_url (host, root, *bld) << endl;
      }

      sm.out.close ();

      if (!sm.wait ())
        error << "sendmail " << *sm.exit;
    }
    // Handle process_error and io_error (both derive from system_error).
    //
    catch (const system_error& e)
    {
      error << "sendmail error: " << e;
    }
  };

  // Don't send the build notification email if the empty package build email
  // is specified.
  //
  optional<email>& build_email (pkg->build_email);
  if (build_notify && (!build_email || !build_email->empty ()))
  {
    // If none of the package build-* addresses is specified, then the build
    // email address is assumed to be the same as the package email address,
    // if specified, otherwise as the project email address, if specified,
    // otherwise the notification email is not sent.
    //
    optional<email> to;

    if (build_email)
      to = move (build_email);
    else if (!pkg->build_warning_email && !pkg->build_error_email)
      to = move (pkg->package_email ? pkg->package_email : pkg->email);

    if (to)
      send_email (*to);
  }

  assert (bld->status);

  // Send the build warning/error notification emails, if requested.
  //
  if (pkg->build_warning_email && *bld->status >= result_status::warning)
    send_email (*pkg->build_warning_email);

  if (pkg->build_error_email && *bld->status >= result_status::error)
    send_email (*pkg->build_error_email);

  return true;
}