// Copyright 2022 Huawei Cloud Computing Technology Co., Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "src/other_tools/root_maps/commit_git_map.hpp"

#include <algorithm>

#include "src/buildtool/file_system/file_root.hpp"
#include "src/other_tools/git_operations/git_repo_remote.hpp"
#include "src/other_tools/just_mr/progress_reporting/progress.hpp"
#include "src/other_tools/just_mr/progress_reporting/statistics.hpp"
#include "src/utils/cpp/tmp_dir.hpp"

namespace {

[[nodiscard]] auto GitURLIsPath(std::string const& url) noexcept -> bool {
    auto prefixes = std::vector<std::string>{"ssh://", "http://", "https://"};
    // return true if no URL prefix exists
    return std::none_of(
        prefixes.begin(), prefixes.end(), [url](auto const& prefix) {
            return (url.rfind(prefix, 0) == 0);
        });
}

void EnsureCommit(GitRepoInfo const& repo_info,
                  std::filesystem::path const& repo_root,
                  GitCASPtr const& git_cas,
                  gsl::not_null<CriticalGitOpMap*> const& critical_git_op_map,
                  std::string const& git_bin,
                  std::vector<std::string> const& launcher,
                  ServeApi* serve_api,
                  gsl::not_null<TaskSystem*> const& ts,
                  CommitGitMap::SetterPtr const& ws_setter,
                  CommitGitMap::LoggerPtr const& logger) {
    // ensure commit exists, and fetch if needed
    auto git_repo = GitRepoRemote::Open(git_cas);  // link fake repo to odb
    if (not git_repo) {
        (*logger)(
            fmt::format("Could not open repository {}", repo_root.string()),
            /*fatal=*/true);
        return;
    }
    // setup wrapped logger
    auto wrapped_logger = std::make_shared<AsyncMapConsumerLogger>(
        [logger](auto const& msg, bool fatal) {
            (*logger)(fmt::format("While checking commit exists:\n{}", msg),
                      fatal);
        });
    auto is_commit_present =
        git_repo->CheckCommitExists(repo_info.hash, wrapped_logger);
    if (is_commit_present == std::nullopt) {
        return;
    }
    if (not is_commit_present.value()) {
        JustMRProgress::Instance().TaskTracker().Start(repo_info.origin);
        // check if commit is known to remote serve service, if asked for an
        // absent root
        if (repo_info.absent) {
            if (serve_api != nullptr) {
                if (auto tree_id = serve_api->RetrieveTreeFromCommit(
                        repo_info.hash, repo_info.subdir)) {
                    // set the workspace root as absent
                    JustMRProgress::Instance().TaskTracker().Stop(
                        repo_info.origin);
                    (*ws_setter)(std::pair(
                        nlohmann::json::array(
                            {repo_info.ignore_special
                                 ? FileRoot::kGitTreeIgnoreSpecialMarker
                                 : FileRoot::kGitTreeMarker,
                             *tree_id}),
                        false));
                    return;
                }
                // give warning
                (*logger)(fmt::format("Tree at subdir {} for commit {} could "
                                      "not be served",
                                      repo_info.subdir,
                                      repo_info.hash),
                          /*fatal=*/false);
            }
            else {
                // give warning
                (*logger)(
                    "Absent root requested, but no serve endpoint provided",
                    /*fatal=*/false);
            }
        }
        // default to fetching it from network
        auto tmp_dir = JustMR::Utils::CreateTypedTmpDir("fetch");
        if (not tmp_dir) {
            (*logger)("Failed to create fetch tmp directory!",
                      /*fatal=*/true);
            return;
        }
        // setup wrapped logger
        auto wrapped_logger = std::make_shared<AsyncMapConsumerLogger>(
            [logger](auto const& msg, bool fatal) {
                (*logger)(fmt::format("While fetching via tmp repo:\n{}", msg),
                          fatal);
            });
        if (not git_repo->FetchViaTmpRepo(tmp_dir->GetPath(),
                                          repo_info.repo_url,
                                          repo_info.branch,
                                          git_bin,
                                          launcher,
                                          wrapped_logger)) {
            return;
        }
        // setup wrapped logger
        wrapped_logger = std::make_shared<AsyncMapConsumerLogger>(
            [logger](auto const& msg, bool fatal) {
                (*logger)(fmt::format("While checking commit exists:\n{}", msg),
                          fatal);
            });
        // check if commit exists now, after fetch
        auto is_commit_present =
            git_repo->CheckCommitExists(repo_info.hash, wrapped_logger);
        if (not is_commit_present) {
            return;
        }
        if (not *is_commit_present) {
            // commit could not be fetched, so fail
            (*logger)(fmt::format("Could not fetch commit {} from branch "
                                  "{} for remote {}",
                                  repo_info.hash,
                                  repo_info.branch,
                                  repo_info.repo_url),
                      /*fatal=*/true);
            return;
        }
        // keep tag
        GitOpKey op_key = {.params =
                               {
                                   repo_root,                    // target_path
                                   repo_info.hash,               // git_hash
                                   "",                           // branch
                                   "Keep referenced tree alive"  // message
                               },
                           .op_type = GitOpType::KEEP_TAG};
        critical_git_op_map->ConsumeAfterKeysReady(
            ts,
            {std::move(op_key)},
            [git_cas, repo_info, repo_root, ws_setter, logger](
                auto const& values) {
                GitOpValue op_result = *values[0];
                // check flag
                if (not op_result.result) {
                    (*logger)("Keep tag failed",
                              /*fatal=*/true);
                    return;
                }
                // ensure commit exists, and fetch if needed
                auto git_repo =
                    GitRepoRemote::Open(git_cas);  // link fake repo to odb
                if (not git_repo) {
                    (*logger)(fmt::format("Could not open repository {}",
                                          repo_root.string()),
                              /*fatal=*/true);
                    return;
                }
                // setup wrapped logger
                auto wrapped_logger = std::make_shared<AsyncMapConsumerLogger>(
                    [logger](auto const& msg, bool fatal) {
                        (*logger)(fmt::format("While getting subtree "
                                              "from commit:\n{}",
                                              msg),
                                  fatal);
                    });
                // get tree id and return workspace root
                auto subtree = git_repo->GetSubtreeFromCommit(
                    repo_info.hash, repo_info.subdir, wrapped_logger);
                if (not subtree) {
                    return;
                }
                // set the workspace root
                JustMRProgress::Instance().TaskTracker().Stop(repo_info.origin);
                auto root = nlohmann::json::array(
                    {repo_info.ignore_special
                         ? FileRoot::kGitTreeIgnoreSpecialMarker
                         : FileRoot::kGitTreeMarker,
                     *subtree});
                if (not repo_info.absent) {
                    root.emplace_back(repo_root);
                }
                (*ws_setter)(std::pair(std::move(root), false));
            },
            [logger, target_path = repo_root](auto const& msg, bool fatal) {
                (*logger)(fmt::format("While running critical Git op "
                                      "KEEP_TAG for target {}:\n{}",
                                      target_path.string(),
                                      msg),
                          fatal);
            });
    }
    else {
        // setup wrapped logger
        auto wrapped_logger = std::make_shared<AsyncMapConsumerLogger>(
            [logger](auto const& msg, bool fatal) {
                (*logger)(
                    fmt::format("While getting subtree from commit:\n{}", msg),
                    fatal);
            });
        // get tree id and return workspace root
        auto subtree = git_repo->GetSubtreeFromCommit(
            repo_info.hash, repo_info.subdir, wrapped_logger);
        if (not subtree) {
            return;
        }
        // set the workspace root
        auto root = nlohmann::json::array(
            {repo_info.ignore_special ? FileRoot::kGitTreeIgnoreSpecialMarker
                                      : FileRoot::kGitTreeMarker,
             *subtree});
        if (not repo_info.absent) {
            root.emplace_back(repo_root);
        }
        (*ws_setter)(std::pair(std::move(root), true));
    }
}

}  // namespace

/// \brief Create a CommitGitMap object
auto CreateCommitGitMap(
    gsl::not_null<CriticalGitOpMap*> const& critical_git_op_map,
    JustMR::PathsPtr const& just_mr_paths,
    std::string const& git_bin,
    std::vector<std::string> const& launcher,
    ServeApi* serve_api,
    std::size_t jobs) -> CommitGitMap {
    auto commit_to_git = [critical_git_op_map,
                          just_mr_paths,
                          git_bin,
                          launcher,
                          serve_api](auto ts,
                                     auto setter,
                                     auto logger,
                                     auto /* unused */,
                                     auto const& key) {
        // get root for repo (making sure that if repo is a path, it is
        // absolute)
        std::string fetch_repo = key.repo_url;
        if (GitURLIsPath(fetch_repo)) {
            fetch_repo = std::filesystem::absolute(fetch_repo).string();
        }
        std::filesystem::path repo_root =
            JustMR::Utils::GetGitRoot(just_mr_paths, fetch_repo);
        // ensure git repo
        // define Git operation to be done
        GitOpKey op_key = {
            .params =
                {
                    repo_root,     // target_path
                    "",            // git_hash
                    "",            // branch
                    std::nullopt,  // message
                    not just_mr_paths->git_checkout_locations.contains(
                        fetch_repo)  // init_bare
                },
            .op_type = GitOpType::ENSURE_INIT};
        critical_git_op_map->ConsumeAfterKeysReady(
            ts,
            {std::move(op_key)},
            [key,
             repo_root,
             critical_git_op_map,
             git_bin,
             launcher,
             serve_api,
             ts,
             setter,
             logger](auto const& values) {
                GitOpValue op_result = *values[0];
                // check flag
                if (not op_result.result) {
                    (*logger)("Git init failed",
                              /*fatal=*/true);
                    return;
                }
                // setup a wrapped_logger
                auto wrapped_logger = std::make_shared<AsyncMapConsumerLogger>(
                    [logger, target_path = repo_root](auto const& msg,
                                                      bool fatal) {
                        (*logger)(fmt::format("While ensuring commit for "
                                              "repository {}:\n{}",
                                              target_path.string(),
                                              msg),
                                  fatal);
                    });
                EnsureCommit(key,
                             repo_root,
                             op_result.git_cas,
                             critical_git_op_map,
                             git_bin,
                             launcher,
                             serve_api,
                             ts,
                             setter,
                             wrapped_logger);
            },
            [logger, target_path = repo_root](auto const& msg, bool fatal) {
                (*logger)(fmt::format("While running critical Git op "
                                      "ENSURE_INIT for target {}:\n{}",
                                      target_path.string(),
                                      msg),
                          fatal);
            });
    };
    return AsyncMapConsumer<GitRepoInfo, std::pair<nlohmann::json, bool>>(
        commit_to_git, jobs);
}