%% -------------------------------------------------------------------
%%
%% xqerl - XQuery processor
%%
%% Copyright (c) 2019-2020 Zachary N. Dean  All Rights Reserved.
%%
%% This file is provided to you 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.
%%
%% -------------------------------------------------------------------

%% @doc Namespace http://xqerl.org/modules/csv
%% Module for reading and writing CSV strings.

-module(xqerl_mod_csv).

-include("xqerl.hrl").

-define(NS, <<"http://xqerl.org/modules/csv">>).
-define(PX, <<"csv">>).

%% ====================================================================
%% API functions
%% ====================================================================
-export([
    parse/2, parse/3,
    serialize/2, serialize/3
]).

-'module-namespace'({?NS, ?PX}).

-variables([]).

-functions([
    {
        {qname, ?NS, ?PX, <<"parse">>},
        {seqType, {funTest, array, [], undefined, any, any}, zero_or_one},
        [],
        {'parse', 2},
        1,
        [
            {seqType, 'xs:string', zero_or_one}
        ]
    },
    {
        {qname, ?NS, ?PX, <<"parse">>},
        {seqType, {funTest, array, [], undefined, any, any}, zero_or_one},
        [],
        {'parse', 3},
        2,
        [
            {seqType, 'xs:string', zero_or_one},
            {seqType, {funTest, map, [], undefined, any, any}, zero_or_one}
        ]
    },
    {
        {qname, ?NS, ?PX, <<"serialize">>},
        {seqType, 'xs:string', zero_or_one},
        [],
        {'serialize', 2},
        1,
        [{seqType, {funTest, array, [], undefined, any, any}, zero_or_one}]
    },
    {
        {qname, ?NS, ?PX, <<"serialize">>},
        {seqType, 'xs:string', zero_or_one},
        [],
        {'serialize', 3},
        2,
        [
            {seqType, {funTest, array, [], undefined, any, any}, zero_or_one},
            {seqType, {funTest, map, [], undefined, any, any}, zero_or_one}
        ]
    }
]).

% block array:array(_) warnings
-dialyzer(no_opaque).

-define(IS_ARRAY(A), is_tuple(A), element(1, A) =:= array).

%% Parse string as CSV input. Returns array of arrays.
%% csv:parse(
%%    $input as xs:string?) as array(*)?
-spec parse(
    xq_types:context(),
    Input :: xq_types:xs_string() | []
) -> xq_types:xq_array() | [].
parse(_Ctx, []) ->
    [];
parse(Ctx, [Input]) ->
    parse(Ctx, Input);
parse(_Ctx, Input) when is_binary(Input) ->
    try
        Str = unicode:characters_to_list(Input),
        {ok, Toks, _} = xqerl_mod_csv_lexer:string(Str),
        {ok, Arrs} = xqerl_mod_csv_parse:parse(Toks),
        array:from_list([array:from_list(R) || R <- Arrs])
    catch
        _:_ ->
            throw_error(parse)
    end;
parse(Ctx, Input) ->
    parse(Ctx, xqerl_types:cast_as(Input, 'xs:string')).

%% Parse string as CSV input. Returns array of arrays.
%% csv:parse(
%%    $input   as xs:string?
%%    $options as map(*)?) as array(*)?
-spec parse(
    xq_types:context(),
    Input :: xq_types:xs_string() | [],
    Options :: xq_types:xq_map() | []
) -> xq_types:xq_array() | [].
parse(_Ctx, [], _) ->
    [];
parse(Ctx, Input, []) ->
    parse(Ctx, Input);
parse(Ctx, [Input], Opt) ->
    parse(Ctx, Input, Opt);
parse(Ctx, Input, [Opt]) ->
    parse(Ctx, Input, Opt);
parse(_Ctx, Input, Options) when is_binary(Input), is_map(Options) ->
    try
        Str = unicode:characters_to_list(Input),
        #{sep := Sep} = parse_options(Options),
        {ok, Toks, _} =
            case Sep of
                comma ->
                    xqerl_mod_csv_lexer:string(Str);
                semicolon ->
                    xqerl_mod_csv_sc_lexer:string(Str);
                tab ->
                    xqerl_mod_csv_t_lexer:string(Str)
            end,
        {ok, Arrs} = xqerl_mod_csv_parse:parse(Toks),
        array:from_list([array:from_list(R) || R <- Arrs])
    catch
        _:_ ->
            throw_error(parse)
    end;
parse(Ctx, Input, Options) ->
    parse(
        Ctx,
        xqerl_types:cast_as(Input, 'xs:string'),
        xqerl_types:cast_as(Options, 'map')
    ).

%% Serialize an array of arrays to CSV.
%% csv:serialize(
%%    $input as array(*)?) as xs:string?
-spec serialize(
    xq_types:context(),
    Input :: xq_types:xq_array() | []
) -> xq_types:xs_string() | [].
serialize(_Ctx, []) ->
    [];
serialize(Ctx, [Input]) ->
    serialize(Ctx, Input);
serialize(_Ctx, Arrays) when ?IS_ARRAY(Arrays) ->
    try
        CP = binary:compile_pattern(<<$">>),
        Sep = <<$,>>,
        Nl = <<13, 10>>,
        Deep = [[quote_row(A, Sep, CP), Nl] || A <- array:to_list(Arrays)],
        erlang:iolist_to_binary(Deep)
    catch
        _:Err ->
            ?dbg("Err", Err),
            throw_error(serialize)
    end;
serialize(Ctx, Input) ->
    serialize(Ctx, xqerl_types:cast_as(Input, 'array')).

%% Serialize an array of arrays to CSV.
%% csv:serialize(
%%    $input as array(*)?,
%%    $options as map(*)?) as xs:string?
-spec serialize(
    xq_types:context(),
    Input :: xq_types:xq_array() | [],
    Options :: xq_types:xq_map() | []
) -> xq_types:xs_string() | [].
serialize(_Ctx, [], _) ->
    [];
serialize(Ctx, Input, []) ->
    serialize(Ctx, Input);
serialize(Ctx, [Input], Opt) ->
    serialize(Ctx, Input, Opt);
serialize(Ctx, Input, [Opt]) ->
    serialize(Ctx, Input, Opt);
serialize(_Ctx, Arrays, Options) when is_map(Options), ?IS_ARRAY(Arrays) ->
    try
        #{
            sep := Sep0,
            quo := Quo
        } = parse_options(Options),
        Sep =
            case Sep0 of
                comma -> <<$,>>;
                semicolon -> <<$;>>;
                tab -> <<$\t>>
            end,
        Nl = <<13, 10>>,
        Deep =
            case Quo of
                false ->
                    [[noquote_row(A, Sep), Nl] || A <- array:to_list(Arrays)];
                true ->
                    CP = binary:compile_pattern(<<$">>),
                    [[quote_row(A, Sep, CP), Nl] || A <- array:to_list(Arrays)]
            end,
        erlang:iolist_to_binary(Deep)
    catch
        _:Err:Stack ->
            ?dbg("Err", Err),
            ?dbg("Err", Stack),
            throw_error(serialize)
    end;
serialize(Ctx, Input, Options) ->
    serialize(
        Ctx,
        xqerl_types:cast_as(Input, 'array'),
        xqerl_types:cast_as(Options, 'map')
    ).

%% ====================================================================
%% Internal functions
%% ====================================================================

default_options() ->
    #{
        sep => comma,
        quo => true
    }.

parse_options(Map) ->
    List = maps:to_list(Map),
    parse_options1(List, default_options()).

parse_options1([{<<"separator">>, {_, Val}} | T], M) ->
    case xqerl_types:string_value(Val) of
        <<"comma">> ->
            parse_options1(T, M#{sep := comma});
        <<"semicolon">> ->
            parse_options1(T, M#{sep := semicolon});
        <<"tab">> ->
            parse_options1(T, M#{sep := tab});
        _ ->
            throw_error(options)
    end;
parse_options1([{<<"quotes">>, {_, Val}} | T], M) ->
    case xqerl_types:cast_as(Val, 'xs:boolean') of
        true ->
            parse_options1(T, M#{quo := true});
        false ->
            parse_options1(T, M#{quo := false});
        _ ->
            throw_error(options)
    end;
parse_options1([_ | T], M) ->
    parse_options1(T, M);
parse_options1([], M) ->
    M.

-dialyzer({[no_return], [throw_error/1]}).

throw_error(options) ->
    ?err('XPST0004');
throw_error(parse) ->
    do_throw(<<"parse">>, <<"Could not parse input.">>);
throw_error(serialize) ->
    do_throw(<<"serialize">>, <<"Could not serialize output.">>).

do_throw(Name, Desc) ->
    E = #xqError{
        description = Desc,
        name = #qname{
            namespace = ?NS,
            prefix = ?PX,
            local_name = Name
        }
    },
    exit(E).

noquote_row(A, Sep) when ?IS_ARRAY(A) ->
    case array:to_list(A) of
        [H | T] ->
            [s(H), [[Sep, s(V)] || V <- T]];
        [] ->
            []
    end;
noquote_row(_, _) ->
    ?err('XPST0004').

quote_row(A, Sep, CP) when ?IS_ARRAY(A) ->
    case array:to_list(A) of
        [H | T] ->
            Q = <<$">>,
            [Q, qs(H, CP), Q, [[Sep, Q, qs(V, CP), Q] || V <- T]];
        [] ->
            []
    end;
quote_row(_, _, _) ->
    ?err('XPST0004').

s(V) -> xqerl_types:string_value(V).

qs(V, CP) ->
    S = xqerl_types:string_value(V),
    maybe_norm(S, CP).

maybe_norm(Bin, CP) ->
    case binary:match(Bin, CP) of
        nomatch ->
            Bin;
        _ ->
            double_quote(Bin)
    end.

double_quote(<<$", Rest/binary>>) ->
    <<$", $", (double_quote(Rest))/binary>>;
double_quote(<<C, Rest/binary>>) ->
    <<C, (double_quote(Rest))/binary>>;
double_quote(<<>>) ->
    <<>>.