%% @author Arjan Scherpenisse <arjan@scherpenisse.net>
%% @copyright 2011 Arjan Scherpenisse <arjan@scherpenisse.net>
%% Date: 2011-10-13

%% @doc Schema definition for the survey module.

%% Copyright 2011 Arjan Scherpenisse
%%
%% 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(mod_survey_schema).
-author("Arjan Scherpenisse <arjan@scherpenisse.net>").

-include_lib("include/zotonic.hrl").
-include("../survey.hrl").

-export([
    manage_schema/2,
    
    survey_to_blocks/2
]).


%% @doc Install tables used for storing survey results
manage_schema(install, Context) ->
    %% This is a workaround for async initialization of the database tables; see github issues #734, #497
    install_survey_answer_table(z_context:prune_for_spawn(Context)),
    
    #datamodel{
        categories=[
            {survey, undefined, [{title, <<"Survey">>}]},
            {poll, survey, [{title, <<"Poll">>}]}
        ]};

manage_schema({upgrade, 2}, Context) ->
    % Replace all survey properties with blocks
    {Low, High} = m_category:get_range_by_name(survey, Context),
    Ids = z_db:q("select id from rsc where pivot_category_nr >= $1 and pivot_category_nr <= $2", [Low, High], Context),
    [
        survey_to_blocks(Id, Context) || {Id} <- Ids
    ],
    ok;

manage_schema({upgrade, 3}, Context) ->
    [] = z_db:q("alter table survey_answer add column is_anonymous boolean not null default false", Context),
    ok.


install_survey_answer_table(Context) ->
    case z_db:table_exists(survey_answer, Context) of
        false ->
            z_db:create_table(survey_answer, [
                        #column_def{name=id, type="serial", is_nullable=false},
                        #column_def{name=survey_id, type="integer", is_nullable=false},
                        #column_def{name=user_id, type="integer", is_nullable=true},
                        #column_def{name=persistent, type="character varying", length=32, is_nullable=true},
                        #column_def{name=is_anonymous, type="boolean", is_nullable=false, default="false"},
                        #column_def{name=question, type="character varying", length=32, is_nullable=false},
                        #column_def{name=name, type="character varying", length=32, is_nullable=false},
                        #column_def{name=value, type="character varying", length=80, is_nullable=true},
                        #column_def{name=text, type="bytea", is_nullable=true},
                        #column_def{name=created, type="timestamp with time zone", is_nullable=true}
                    ], Context),

            % Add some indices and foreign keys, ignore errors
            z_db:equery("create index fki_survey_answer_survey_id on survey_answer(survey_id)", Context),
            z_db:equery("alter table survey_answer add 
                        constraint fk_survey_answer_survey_id foreign key (survey_id) references rsc(id) 
                        on update cascade on delete cascade", Context),

            z_db:equery("create index fki_survey_answer_user_id on survey_answer(user_id)", Context),
            z_db:equery("alter table survey_answer add 
                        constraint fk_survey_answer_user_id foreign key (user_id) references rsc(id) 
                        on update cascade on delete cascade", Context),

            %% For aggregating answers to survey questions (group by name)
            z_db:equery("create index survey_answer_survey_name_key on survey_answer(survey_id, name)", Context),
            z_db:equery("create index survey_answer_survey_question_key on survey_answer(survey_id, question)", Context),
            z_db:equery("create index survey_answer_survey_user_key on survey_answer(survey_id, user_id)", Context),
            z_db:equery("create index survey_answer_survey_persistent_key on survey_answer(survey_id, persistent)", Context);
                        
        true ->
            ok
    end.
    
    

survey_to_blocks(Id, Context) ->
    case m_rsc:p_no_acl(Id, survey, Context) of
        undefined -> 
            ok;
        {survey, QIds, Qs} ->
            QBlocks = [
                question_to_block(proplists:get_value(QId, Qs))
                || QId <- QIds
            ],
            CurrBlocks = to_list(m_rsc:p_no_acl(Id, blocks, Context)),
            m_rsc_update:update(Id,
                                [
                                    {survey, undefined},
                                    {blocks, CurrBlocks++QBlocks}
                                ], 
                                z_acl:sudo(Context)),
            ok
    end.
    
    to_list(undefined) -> [];
    to_list(<<>>) -> [];
    to_list(L) when is_list(L) -> L.

    question_to_block(#survey_question{type=likert} = Q) -> survey_q_likert:to_block(Q);
    question_to_block(#survey_question{type=longanswer} = Q) -> survey_q_long_answer:to_block(Q);
    question_to_block(#survey_question{type=matching} = Q) -> survey_q_matching:to_block(Q);
    question_to_block(#survey_question{type=narrative} = Q) -> survey_q_narrative:to_block(Q);
    question_to_block(#survey_question{type=pagebreak} = Q) -> survey_q_page_break:to_block(Q);
    question_to_block(#survey_question{type=shortanswer} = Q) -> survey_q_short_answer:to_block(Q);
    question_to_block(#survey_question{type=thurstone} = Q) -> survey_q_thurstone:to_block(Q);
    question_to_block(#survey_question{type=truefalse} = Q) -> survey_q_truefalse:to_block(Q);
    question_to_block(#survey_question{type=yesno} = Q) -> survey_q_yesno:to_block(Q);
    question_to_block(#survey_question{type=multiple_choice} = Q) -> survey_q_multiple_choice:to_block(Q);
    question_to_block(#survey_question{type=subhead, name=Name, question=Q}) ->
        [
            {type, header},
            {name, z_convert:to_binary(Name)},
            {header, z_convert:to_binary(Q)}
        ];
    question_to_block(#survey_question{type=prompt, name=Name, question=Q}) ->
        [
            {type, text},
            {name, z_convert:to_binary(Name)},
            {body, z_convert:to_binary(["<p>",Q,"</p>"])}
        ];
    question_to_block(#survey_question{type=textblock, name=Name, question=Q}) ->
        [
            {type, text},
            {name, z_convert:to_binary(Name)},
            {body, z_convert:to_binary(["<p>",Q,"</p>"])}
        ].