% 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.

-module(couch_mrview_purge_docs_fabric_tests).

-include_lib("couch/include/couch_eunit.hrl").
-include_lib("couch/include/couch_db.hrl").
-include_lib("mem3/include/mem3.hrl").
-include_lib("couch_mrview/include/couch_mrview.hrl").

-define(TIMEOUT, 60). % seconds


setup_all() ->
    Ctx = test_util:start_couch([fabric, mem3]),
    meck:new(couch_mrview_index, [passthrough]),
    Ctx.


teardown_all(Ctx) ->
    meck:unload(),
    test_util:stop_couch(Ctx).


setup() ->
    DbName = ?tempdb(),
    ok = fabric:create_db(DbName, [?ADMIN_CTX, {q, 1}]),
    meck:reset([couch_mrview_index]),
    meck:expect(couch_mrview_index, ensure_local_purge_docs, fun(A, B) ->
        meck:passthrough([A, B])
    end),
    DbName.


teardown(DbName) ->
    ok = fabric:delete_db(DbName, [?ADMIN_CTX]).


view_purge_fabric_test_() ->
    {
        "Map views",
        {
            setup,
            fun setup_all/0,
            fun teardown_all/1,
            {
                foreach,
                fun setup/0,
                fun teardown/1,
                [
                    fun test_purge_verify_index/1,
                    fun test_purge_hook_before_compaction/1
                ]
            }
        }
    }.


test_purge_verify_index(DbName) ->
    {timeout, ?TIMEOUT, ?_test(begin
        Docs1 = couch_mrview_test_util:make_docs(normal, 5),
        {ok, _} = fabric:update_docs(DbName, Docs1, [?ADMIN_CTX]),
        {ok, _} = fabric:update_doc(
            DbName,
            couch_mrview_test_util:ddoc(map),
            [?ADMIN_CTX]
        ),

        Result1 = fabric:query_view(DbName, <<"bar">>, <<"baz">>, #mrargs{}),
        Expect1 = {ok, [
            {meta, [{total, 5}, {offset, 0}]},
            {row, [{id, <<"1">>}, {key, 1}, {value, 1}]},
            {row, [{id, <<"2">>}, {key, 2}, {value, 2}]},
            {row, [{id, <<"3">>}, {key, 3}, {value, 3}]},
            {row, [{id, <<"4">>}, {key, 4}, {value, 4}]},
            {row, [{id, <<"5">>}, {key, 5}, {value, 5}]}
        ]},
        ?assertEqual(Expect1, Result1),

        {ok, #doc{body = {Props1}}} = get_local_purge_doc(DbName),
        ?assertEqual(0, couch_util:get_value(<<"purge_seq">>, Props1)),
        ShardNames = [Sh || #shard{name = Sh} <- mem3:local_shards(DbName)],
        [ShardDbName | _Rest ] = ShardNames,
        ?assertEqual(true, couch_mrview_index:verify_index_exists(
            ShardDbName, Props1)),

        purge_docs(DbName, [<<"1">>]),

        Result2 = fabric:query_view(DbName, <<"bar">>, <<"baz">>, #mrargs{}),
        Expect2 = {ok, [
            {meta, [{total, 4}, {offset, 0}]},
            {row, [{id, <<"2">>}, {key, 2}, {value, 2}]},
            {row, [{id, <<"3">>}, {key, 3}, {value, 3}]},
            {row, [{id, <<"4">>}, {key, 4}, {value, 4}]},
            {row, [{id, <<"5">>}, {key, 5}, {value, 5}]}
        ]},
        ?assertEqual(Expect2, Result2),

        {ok, #doc{body = {Props2}}} = get_local_purge_doc(DbName),
        ?assertEqual(1, couch_util:get_value(<<"purge_seq">>, Props2)),
        ?assertEqual(true, couch_mrview_index:verify_index_exists(
            ShardDbName, Props2))
    end)}.


test_purge_hook_before_compaction(DbName) ->
    {timeout, ?TIMEOUT, ?_test(begin
        Docs1 = couch_mrview_test_util:make_docs(normal, 5),
        {ok, _} = fabric:update_docs(DbName, Docs1, [?ADMIN_CTX]),
        {ok, _} = fabric:update_doc(
            DbName,
            couch_mrview_test_util:ddoc(map),
            [?ADMIN_CTX]
        ),

        Result1 = fabric:query_view(DbName, <<"bar">>, <<"baz">>, #mrargs{}),
        Expect1 = {ok, [
            {meta, [{total, 5}, {offset, 0}]},
            {row, [{id, <<"1">>}, {key, 1}, {value, 1}]},
            {row, [{id, <<"2">>}, {key, 2}, {value, 2}]},
            {row, [{id, <<"3">>}, {key, 3}, {value, 3}]},
            {row, [{id, <<"4">>}, {key, 4}, {value, 4}]},
            {row, [{id, <<"5">>}, {key, 5}, {value, 5}]}
        ]},
        ?assertEqual(Expect1, Result1),

        purge_docs(DbName, [<<"1">>]),

        Result2 = fabric:query_view(DbName, <<"bar">>, <<"baz">>, #mrargs{}),
        Expect2 = {ok, [
            {meta, [{total, 4}, {offset, 0}]},
            {row, [{id, <<"2">>}, {key, 2}, {value, 2}]},
            {row, [{id, <<"3">>}, {key, 3}, {value, 3}]},
            {row, [{id, <<"4">>}, {key, 4}, {value, 4}]},
            {row, [{id, <<"5">>}, {key, 5}, {value, 5}]}
        ]},
        ?assertEqual(Expect2, Result2),

        {ok, #doc{body = {Props1}}} = get_local_purge_doc(DbName),
        ?assertEqual(1, couch_util:get_value(<<"purge_seq">>, Props1)),

        [ShardName | _] = local_shards(DbName),
        couch_util:with_db(ShardName, fun(Db) ->
            {ok, _} = couch_db:start_compact(Db)
        end),
        wait_compaction(ShardName, ?LINE),

        ?assertEqual(ok, meck:wait(1, couch_mrview_index,
            ensure_local_purge_docs, '_', 5000)
        ),

        % Make sure compaction didn't change the update seq
        {ok, #doc{body = {Props1}}} = get_local_purge_doc(DbName),
        ?assertEqual(1, couch_util:get_value(<<"purge_seq">>, Props1)),

        purge_docs(DbName, [<<"2">>]),

        couch_util:with_db(ShardName, fun(Db) ->
            {ok, _} = couch_db:start_compact(Db)
        end),
        wait_compaction(ShardName, ?LINE),

        ?assertEqual(ok, meck:wait(2, couch_mrview_index,
            ensure_local_purge_docs, '_', 5000)
        ),

        % Make sure compaction after a purge didn't overwrite
        % the local purge doc for the index
        {ok, #doc{body = {Props2}}} = get_local_purge_doc(DbName),
        ?assertEqual(1, couch_util:get_value(<<"purge_seq">>, Props2)),

        % Force another update to ensure that we update
        % the local doc appropriate after compaction
        Result3 = fabric:query_view(DbName, <<"bar">>, <<"baz">>, #mrargs{}),
        Expect3 = {ok, [
            {meta, [{total, 3}, {offset, 0}]},
            {row, [{id, <<"3">>}, {key, 3}, {value, 3}]},
            {row, [{id, <<"4">>}, {key, 4}, {value, 4}]},
            {row, [{id, <<"5">>}, {key, 5}, {value, 5}]}
        ]},
        ?assertEqual(Expect3, Result3),

        {ok, #doc{body = {Props3}}} = get_local_purge_doc(DbName),
        ?assertEqual(2, couch_util:get_value(<<"purge_seq">>, Props3)),

        % Check that if the local doc doesn't exist that one
        % is created for the index on compaction
        delete_local_purge_doc(DbName),
        ?assertMatch({not_found, _}, get_local_purge_doc(DbName)),

        couch_util:with_db(ShardName, fun(Db) ->
            {ok, _} = couch_db:start_compact(Db)
        end),
        wait_compaction(ShardName, ?LINE),

        ?assertEqual(ok, meck:wait(3, couch_mrview_index,
            ensure_local_purge_docs, '_', 5000)
        ),

        {ok, #doc{body = {Props4}}} = get_local_purge_doc(DbName),
        ?assertEqual(2, couch_util:get_value(<<"purge_seq">>, Props4))
    end)}.


get_local_purge_doc(DbName) ->
    {ok, DDoc} = fabric:open_doc(DbName, <<"_design/bar">>, []),
    {ok, IdxState} = couch_mrview_util:ddoc_to_mrst(DbName, DDoc),
    Sig = IdxState#mrst.sig,
    HexSig = list_to_binary(couch_index_util:hexsig(Sig)),
    DocId = couch_mrview_util:get_local_purge_doc_id(HexSig),
    [ShardName | _] = local_shards(DbName),
    couch_util:with_db(ShardName, fun(Db) ->
        couch_db:open_doc(Db, DocId, [])
    end).


delete_local_purge_doc(DbName) ->
    {ok, DDoc} = fabric:open_doc(DbName, <<"_design/bar">>, []),
    {ok, IdxState} = couch_mrview_util:ddoc_to_mrst(DbName, DDoc),
    Sig = IdxState#mrst.sig,
    HexSig = list_to_binary(couch_index_util:hexsig(Sig)),
    DocId = couch_mrview_util:get_local_purge_doc_id(HexSig),
    NewDoc = #doc{id = DocId, deleted = true},
    [ShardName | _] = local_shards(DbName),
    couch_util:with_db(ShardName, fun(Db) ->
        {ok, _} = couch_db:update_doc(Db, NewDoc, [])
    end).


get_rev(#full_doc_info{} = FDI) ->
    #doc_info{
        revs = [#rev_info{} = PrevRev | _]
    } = couch_doc:to_doc_info(FDI),
    PrevRev#rev_info.rev.


purge_docs(DbName, DocIds) ->
    lists:foreach(fun(DocId) ->
        FDI = fabric:get_full_doc_info(DbName, DocId, []),
        Rev = get_rev(FDI),
        {ok, [{ok, _}]} = fabric:purge_docs(DbName, [{DocId, [Rev]}], [])
    end, DocIds).


wait_compaction(DbName, Line) ->
    WaitFun = fun() ->
        case is_compaction_running(DbName) of
            true -> wait;
            false -> ok
        end
    end,
    case test_util:wait(WaitFun, 10000) of
        timeout ->
            erlang:error({assertion_failed, [
                    {module, ?MODULE},
                    {line, Line},
                    {reason, "Timeout waiting for database compaction"}
                ]});
        _ ->
            ok
    end.


is_compaction_running(DbName) ->
    {ok, DbInfo} = couch_util:with_db(DbName, fun(Db) ->
        couch_db:get_db_info(Db)
    end),
    couch_util:get_value(compact_running, DbInfo).


local_shards(DbName) ->
    try
        [ShardName || #shard{name = ShardName} <- mem3:local_shards(DbName)]
    catch
        error:database_does_not_exist ->
            []
    end.