/*
 *
 * Modified by ScyllaDB
 * Copyright (C) 2020-present ScyllaDB
 */

/*
 * SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
 *
 * Copyright (C) 2020-present ScyllaDB
 */

#include <boost/range/adaptors.hpp>
#include <seastar/core/coroutine.hh>
#include <seastar/coroutine/maybe_yield.hh>
#include "db/snapshot-ctl.hh"
#include "replica/database.hh"

namespace db {

future<> snapshot_ctl::check_snapshot_not_exist(sstring ks_name, sstring name, std::optional<std::vector<sstring>> filter) {
    auto& ks = _db.local().find_keyspace(ks_name);
    return parallel_for_each(ks.metadata()->cf_meta_data(), [this, ks_name = std::move(ks_name), name = std::move(name), filter = std::move(filter)] (auto& pair) {
        auto& cf_name = pair.first;
        if (filter && std::find(filter->begin(), filter->end(), cf_name) == filter->end()) {
            return make_ready_future<>();
        }        
        auto& cf = _db.local().find_column_family(pair.second);
        return cf.snapshot_exists(name).then([ks_name = std::move(ks_name), name] (bool exists) {
            if (exists) {
                throw std::runtime_error(format("Keyspace {}: snapshot {} already exists.", ks_name, name));
            }
        });
    });
}

template <typename Func>
std::result_of_t<Func()> snapshot_ctl::run_snapshot_modify_operation(Func&& f) {
    return with_gate(_ops, [f = std::move(f), this] () {
        return container().invoke_on(0, [f = std::move(f)] (snapshot_ctl& snap) mutable {
            return with_lock(snap._lock.for_write(), std::move(f));
        });
    });
}

template <typename Func>
std::result_of_t<Func()> snapshot_ctl::run_snapshot_list_operation(Func&& f) {
    return with_gate(_ops, [f = std::move(f), this] () {
        return container().invoke_on(0, [f = std::move(f)] (snapshot_ctl& snap) mutable {
            return with_lock(snap._lock.for_read(), std::move(f));
        });
    });
}

future<> snapshot_ctl::take_snapshot(sstring tag, std::vector<sstring> keyspace_names, skip_flush sf) {
    if (tag.empty()) {
        throw std::runtime_error("You must supply a snapshot name.");
    }

    if (keyspace_names.size() == 0) {
        boost::copy(_db.local().get_keyspaces() | boost::adaptors::map_keys, std::back_inserter(keyspace_names));
    };

    return run_snapshot_modify_operation([tag = std::move(tag), keyspace_names = std::move(keyspace_names), sf, this] {
        return parallel_for_each(keyspace_names, [tag, this] (auto& ks_name) {
            return check_snapshot_not_exist(ks_name, tag);
        }).then([this, tag, keyspace_names, sf] {
            return _db.invoke_on_all([tag = std::move(tag), keyspace_names, sf] (replica::database& db) {
                return parallel_for_each(keyspace_names, [&db, tag = std::move(tag), sf] (auto& ks_name) {
                    auto& ks = db.find_keyspace(ks_name);
                    return parallel_for_each(ks.metadata()->cf_meta_data(), [&db, tag = std::move(tag), sf] (auto& pair) {
                        auto& cf = db.find_column_family(pair.second);
                        return cf.snapshot(db, tag, bool(sf));
                    });
                });
            });
        });
    });
}

future<> snapshot_ctl::take_column_family_snapshot(sstring ks_name, std::vector<sstring> tables, sstring tag, skip_flush sf) {
    if (ks_name.empty()) {
        throw std::runtime_error("You must supply a keyspace name");
    }
    if (tables.empty()) {
        throw std::runtime_error("You must supply a table name");
    }
    if (tag.empty()) {
        throw std::runtime_error("You must supply a snapshot name.");
    }

    return run_snapshot_modify_operation([this, ks_name = std::move(ks_name), tables = std::move(tables), tag = std::move(tag), sf] {
        return check_snapshot_not_exist(ks_name, tag, tables).then([this, ks_name, tables, tag, sf] {
            return do_with(std::vector<sstring>(std::move(tables)),[this, ks_name, tag, sf](const std::vector<sstring>& tables) {
                return do_for_each(tables, [ks_name, tag, sf, this] (const sstring& table_name) {
                    if (table_name.find(".") != sstring::npos) {
                        throw std::invalid_argument("Cannot take a snapshot of a secondary index by itself. Run snapshot on the table that owns the index.");
                    }
                    return _db.invoke_on_all([ks_name, table_name, tag, sf] (replica::database &db) {
                        auto& cf = db.find_column_family(ks_name, table_name);
                        return cf.snapshot(db, tag, bool(sf));
                    });
                });
            });
        });
    });
}

future<> snapshot_ctl::take_column_family_snapshot(sstring ks_name, sstring cf_name, sstring tag, skip_flush sf) {
    return take_column_family_snapshot(ks_name, std::vector<sstring>{cf_name}, tag, sf);
}

future<> snapshot_ctl::clear_snapshot(sstring tag, std::vector<sstring> keyspace_names, sstring cf_name) {
    return run_snapshot_modify_operation([this, tag = std::move(tag), keyspace_names = std::move(keyspace_names), cf_name = std::move(cf_name)] {
        return _db.local().clear_snapshot(tag, keyspace_names, cf_name);
    });
}

future<std::unordered_map<sstring, std::vector<snapshot_ctl::snapshot_details>>>
snapshot_ctl::get_snapshot_details() {
    using snapshot_map = std::unordered_map<sstring, std::vector<snapshot_ctl::snapshot_details>>;

    co_return co_await run_snapshot_list_operation([this] () -> future<snapshot_map> {
        snapshot_map result;
        for (auto& r : co_await _db.local().get_snapshot_details()) {
            result[r.snapshot_name].emplace_back(std::move(r.details));
        }
        co_return result;
    });
}

future<int64_t> snapshot_ctl::true_snapshots_size() {
    co_return co_await run_snapshot_list_operation([this] () -> future<int64_t> {
        int64_t total = 0;
        for (auto& r : co_await _db.local().get_snapshot_details()) {
            total += r.details.live;
        }
        co_return total;
    });
}

}