% 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(cpse_test_fold_purge_infos).
-compile(export_all).
-compile(nowarn_export_all).

-include_lib("eunit/include/eunit.hrl").
-include_lib("couch/include/couch_db.hrl").

-define(NUM_DOCS, 100).

setup_each() ->
    {ok, Db} = cpse_util:create_db(),
    Db.

teardown_each(Db) ->
    ok = couch_server:delete(couch_db:name(Db), []).

cpse_empty_purged_docs(Db) ->
    ?assertEqual(
        {ok, []},
        couch_db_engine:fold_purge_infos(
            Db, 0, fun fold_fun/2, [], []
        )
    ).

cpse_all_purged_docs(Db1) ->
    {RActions, RIds} = lists:foldl(
        fun(Id, {CActions, CIds}) ->
            Id1 = docid(Id),
            Action = {create, {Id1, {[{<<"int">>, Id}]}}},
            {[Action | CActions], [Id1 | CIds]}
        end,
        {[], []},
        lists:seq(1, ?NUM_DOCS)
    ),
    Actions = lists:reverse(RActions),
    Ids = lists:reverse(RIds),
    {ok, Db2} = cpse_util:apply_batch(Db1, Actions),

    FDIs = couch_db_engine:open_docs(Db2, Ids),
    {RevActions2, RevIdRevs} = lists:foldl(
        fun(FDI, {CActions, CIdRevs}) ->
            Id = FDI#full_doc_info.id,
            PrevRev = cpse_util:prev_rev(FDI),
            Rev = PrevRev#rev_info.rev,
            Action = {purge, {Id, Rev}},
            {[Action | CActions], [{Id, [Rev]} | CIdRevs]}
        end,
        {[], []},
        FDIs
    ),
    {Actions2, IdsRevs} = {lists:reverse(RevActions2), lists:reverse(RevIdRevs)},

    {ok, Db3} = cpse_util:apply_batch(Db2, Actions2),
    {ok, PurgedIdRevs} = couch_db_engine:fold_purge_infos(
        Db3, 0, fun fold_fun/2, [], []
    ),
    ?assertEqual(IdsRevs, lists:reverse(PurgedIdRevs)).

cpse_start_seq(Db1) ->
    Actions1 = [
        {create, {docid(1), {[{<<"int">>, 1}]}}},
        {create, {docid(2), {[{<<"int">>, 2}]}}},
        {create, {docid(3), {[{<<"int">>, 3}]}}},
        {create, {docid(4), {[{<<"int">>, 4}]}}},
        {create, {docid(5), {[{<<"int">>, 5}]}}}
    ],
    Ids = [docid(1), docid(2), docid(3), docid(4), docid(5)],
    {ok, Db2} = cpse_util:apply_actions(Db1, Actions1),

    FDIs = couch_db_engine:open_docs(Db2, Ids),
    {RActions2, RIdRevs} = lists:foldl(
        fun(FDI, {CActions, CIdRevs}) ->
            Id = FDI#full_doc_info.id,
            PrevRev = cpse_util:prev_rev(FDI),
            Rev = PrevRev#rev_info.rev,
            Action = {purge, {Id, Rev}},
            {[Action | CActions], [{Id, [Rev]} | CIdRevs]}
        end,
        {[], []},
        FDIs
    ),
    {ok, Db3} = cpse_util:apply_actions(Db2, lists:reverse(RActions2)),

    StartSeq = 3,
    StartSeqIdRevs = lists:nthtail(StartSeq, lists:reverse(RIdRevs)),
    {ok, PurgedIdRevs} = couch_db_engine:fold_purge_infos(
        Db3, StartSeq, fun fold_fun/2, [], []
    ),
    ?assertEqual(StartSeqIdRevs, lists:reverse(PurgedIdRevs)).

cpse_id_rev_repeated(Db1) ->
    Actions1 = [
        {create, {<<"foo">>, {[{<<"vsn">>, 1}]}}},
        {conflict, {<<"foo">>, {[{<<"vsn">>, 2}]}}}
    ],
    {ok, Db2} = cpse_util:apply_actions(Db1, Actions1),

    [FDI1] = couch_db_engine:open_docs(Db2, [<<"foo">>]),
    PrevRev1 = cpse_util:prev_rev(FDI1),
    Rev1 = PrevRev1#rev_info.rev,
    Actions2 = [
        {purge, {<<"foo">>, Rev1}}
    ],

    {ok, Db3} = cpse_util:apply_actions(Db2, Actions2),
    {ok, PurgedIdRevs1} = couch_db_engine:fold_purge_infos(
        Db3, 0, fun fold_fun/2, [], []
    ),
    ExpectedPurgedIdRevs1 = [
        {<<"foo">>, [Rev1]}
    ],

    ?assertEqual(ExpectedPurgedIdRevs1, lists:reverse(PurgedIdRevs1)),
    ?assertEqual(1, couch_db_engine:get_purge_seq(Db3)),

    % purge the same Id,Rev when the doc still exists
    {ok, Db4} = cpse_util:apply_actions(Db3, Actions2),
    {ok, PurgedIdRevs2} = couch_db_engine:fold_purge_infos(
        Db4, 0, fun fold_fun/2, [], []
    ),
    ExpectedPurgedIdRevs2 = [
        {<<"foo">>, [Rev1]},
        {<<"foo">>, [Rev1]}
    ],
    ?assertEqual(ExpectedPurgedIdRevs2, lists:reverse(PurgedIdRevs2)),
    ?assertEqual(2, couch_db_engine:get_purge_seq(Db4)),

    [FDI2] = couch_db_engine:open_docs(Db4, [<<"foo">>]),
    PrevRev2 = cpse_util:prev_rev(FDI2),
    Rev2 = PrevRev2#rev_info.rev,
    Actions3 = [
        {purge, {<<"foo">>, Rev2}}
    ],
    {ok, Db5} = cpse_util:apply_actions(Db4, Actions3),

    {ok, PurgedIdRevs3} = couch_db_engine:fold_purge_infos(
        Db5, 0, fun fold_fun/2, [], []
    ),
    ExpectedPurgedIdRevs3 = [
        {<<"foo">>, [Rev1]},
        {<<"foo">>, [Rev1]},
        {<<"foo">>, [Rev2]}
    ],
    ?assertEqual(ExpectedPurgedIdRevs3, lists:reverse(PurgedIdRevs3)),
    ?assertEqual(3, couch_db_engine:get_purge_seq(Db5)),

    % purge the same Id,Rev when the doc was completely purged
    {ok, Db6} = cpse_util:apply_actions(Db5, Actions3),

    {ok, PurgedIdRevs4} = couch_db_engine:fold_purge_infos(
        Db6, 0, fun fold_fun/2, [], []
    ),
    ExpectedPurgedIdRevs4 = [
        {<<"foo">>, [Rev1]},
        {<<"foo">>, [Rev1]},
        {<<"foo">>, [Rev2]},
        {<<"foo">>, [Rev2]}
    ],
    ?assertEqual(ExpectedPurgedIdRevs4, lists:reverse(PurgedIdRevs4)),
    ?assertEqual(4, couch_db_engine:get_purge_seq(Db6)).

fold_fun({_PSeq, _UUID, Id, Revs}, Acc) ->
    {ok, [{Id, Revs} | Acc]}.

docid(I) ->
    Str = io_lib:format("~4..0b", [I]),
    iolist_to_binary(Str).