// file      : libbuild2/dist/init.cxx -*- C++ -*-
// license   : MIT; see accompanying LICENSE file

#include <libbuild2/dist/init.hxx>

#include <libbuild2/file.hxx>
#include <libbuild2/rule.hxx>
#include <libbuild2/scope.hxx>
#include <libbuild2/diagnostics.hxx>

#include <libbuild2/config/utility.hxx>

#include <libbuild2/dist/rule.hxx>
#include <libbuild2/dist/module.hxx>
#include <libbuild2/dist/operation.hxx>

using namespace std;
using namespace butl;

namespace build2
{
  namespace dist
  {
    static const rule rule_;

    void
    boot (scope& rs, const location&, module_boot_extra& extra)
    {
      tracer trace ("dist::boot");

      l5 ([&]{trace << "for " << rs;});

      // Enter module variables. Do it during boot in case they get assigned
      // in bootstrap.build (which is customary for, e.g., dist.package).
      //

      // The dist flag or path. Normally it is a flag (true or false) but can
      // also be used to remap the distribution location.
      //
      // In the latter case it specifies the "imaginary" source location which
      // is used to derive the corresponding distribution local. This location
      // can be specified as either a directory path (to remap with the same
      // file name) or a file path (to remap with a different name). And the
      // way we distinguish between the two is via the presence/absence of the
      // trailing directory separator. If the path is relative, then it's
      // treated relative to the target directory. Note that to make things
      // less error prone, simple paths without any directory separators are
      // not allowed (use ./<name> instead).
      //
      // Note that if multiple targets end up with the same source location,
      // the behavior is undefined and no diagnostics is issued.
      //
      // Note also that such remapping has no effect in the bootstrap
      // distribution mode.
      //
      // Note: project-private.
      //
      rs.var_pool ().insert<path> ("dist", variable_visibility::target);

      // The rest of the variables we enter are qualified so go straight for
      // the public variable pool.
      //
      auto& vp (rs.var_pool (true /* public */));

      // config.dist.archives is a list of archive extensions (e.g., zip,
      // tar.gz) that can be optionally prefixed with a directory. If it is
      // relative, then it is prefixed with config.dist.root. Otherwise, the
      // archive is written to the absolute location.
      //
      // config.dist.checksums is a list of archive checksum extensions (e.g.,
      // sha1, sha256) that can also be optionally prefixed with a directory
      // with the same semantics as config.dist.archives. If the directory is
      // absent, then the checksum file is written into the same directory as
      // the corresponding archive.
      //
      vp.insert<abs_dir_path> ("config.dist.root");
      vp.insert<paths>        ("config.dist.archives");
      vp.insert<paths>        ("config.dist.checksums");
      vp.insert<path>         ("config.dist.cmd");

      // Allow distribution of uncommitted projects. This is enforced by the
      // version module.
      //
      vp.insert<bool> ("config.dist.uncommitted");

      // The bootstrap distribution mode. Note that it can only be specified
      // as a global override and is thus marked as unsaved in init(). Unlike
      // the normal load distribution mode, we can do in source and multiple
      // projects at once.
      //
      // Note also that other config.dist.* variables can only be specified as
      // overrides (since config.build is not loaded) but do not have to be
      // global.
      //
      auto& v_d_b (vp.insert<bool> ("config.dist.bootstrap"));

      vp.insert<dir_path>     ("dist.root");
      vp.insert<process_path> ("dist.cmd");
      vp.insert<paths>        ("dist.archives");
      vp.insert<paths>        ("dist.checksums");

      // Project's package name. Note: if set, must be in bootstrap.build.
      //
      auto& v_d_p (vp.insert<string> ("dist.package"));

      // See if we need to use the bootstrap mode.
      //
      bool bm (cast_false<bool> (rs.global_scope ()[v_d_b]));

      // Register the meta-operation.
      //
      rs.insert_meta_operation (dist_id,
                                bm ? mo_dist_bootstrap : mo_dist_load);

      // Create the module.
      //
      extra.set_module (new module (v_d_p));
    }

    // This code is reused by the bootstrap mode.
    //
    void
    init_config (scope& rs)
    {
      // Note that we don't use any defaults for root -- the location
      // must be explicitly specified or we will complain if and when
      // we try to dist.
      //
      using config::lookup_config;
      using config::specified_config;

      // Note: ignore config.dist.bootstrap.
      //
      bool s (specified_config (rs, "dist", {"bootstrap"}));

      // config.dist.root
      //
      {
        value& v (rs.assign ("dist.root"));

        if (s)
        {
          if (lookup l = lookup_config (rs, "config.dist.root", nullptr))
            v = cast<dir_path> (l); // Strip abs_dir_path.
        }
      }

      // config.dist.cmd
      //
      // By default we use in-process code for creating directories and
      // copying files (for performance, especially on Windows). But an
      // external program (normally install) can be used if configured.
      //
      {
        value& v (rs.assign<process_path> ("dist.cmd")); // NULL

        if (s)
        {
          if (lookup l = lookup_config (rs, "config.dist.cmd", nullptr))
            v = run_search (cast<path> (l), true);
        }
      }

      // config.dist.archives
      // config.dist.checksums
      //
      {
        value& a (rs.assign ("dist.archives"));
        value& c (rs.assign ("dist.checksums"));

        if (s)
        {
          if (lookup l = lookup_config (rs, "config.dist.archives", nullptr))
            a = *l;

          if (lookup l = lookup_config (rs, "config.dist.checksums", nullptr))
          {
            c = *l;

            if (!c.empty () && (!a || a.empty ()))
              fail << "config.dist.checksums specified without "
                   << "config.dist.archives";

          }
        }
      }

      // config.dist.uncommitted
      //
      // Omit it from the configuration unless specified.
      //
      lookup_config (rs, "config.dist.uncommitted");
    }

    bool
    init (scope& rs,
          scope&,
          const location& l,
          bool first,
          bool,
          module_init_extra&)
    {
      tracer trace ("dist::init");

      if (!first)
      {
        warn (l) << "multiple dist module initializations";
        return true;
      }

      l5 ([&]{trace << "for " << rs;});

      auto& vp (rs.var_pool (true /* public */)); // All qualified.

      // Register our wildcard rule. Do it explicitly for the alias to prevent
      // something like insert<target>(dist_id, test_id) taking precedence.
      //
      rs.insert_rule<target> (dist_id, 0, "dist",       rule_);
      rs.insert_rule<alias>  (dist_id, 0, "dist.alias", rule_);

      // We need this rule for out-of-any-project dependencies (for example,
      // executables imported from /usr/bin, etc). We are registering it on
      // the global scope similar to builtin rules.
      //
      // See a similar rule in the config module.
      //
      rs.global_scope ().insert_rule<mtime_target> (
        dist_id, 0, "dist.file", file_rule::instance);

      // Configuration.
      //
      // Adjust module priority so that the config.dist.* values are saved at
      // the end of config.build.
      //
      // Note: must be done regardless of specified_config() result due to
      // the unsave_variable() call below.
      //
      config::save_module (rs, "dist", INT32_MAX);

      init_config (rs);

      // dist.bootstrap
      //
      {
        auto& v (*vp.find ("config.dist.bootstrap"));

        // If specified, verify it is a global override.
        //
        if (lookup l = rs[v])
        {
          if (!l.belongs (rs.global_scope ()))
            fail << "config.dist.bootstrap must be a global override" <<
              info << "specify !config.dist.bootstrap=...";
        }

        config::unsave_variable (rs, v);
      }

      // Environment.
      //
      // Preparing a distribution may involve executing the following
      // programs:
      //
      // install
      //
      //   While some install implementations recognize environment variables,
      //   none of them affect our invocations (see the install module for
      //   analysis).
      //
      // *sum programs (md5sum, sha1sum, sha256sum, etc)
      //
      //   These do not recognize any environment variables (at least the
      //   GNU coreutils versions).
      //
      //
      // tar, zip, gzip, xz (and whatever tar may invoke)
      //
      //   This is a can of worms that we currently don't touch (perhaps this
      //   will sort itself out if/when we switch to libarchive).

      return true;
    }

    static const module_functions mod_functions[] =
    {
      {"dist",  &boot,   &init},
      {nullptr, nullptr, nullptr}
    };

    const module_functions*
    build2_dist_load ()
    {
      return mod_functions;
    }
  }
}
