-module(storch).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([migrate/2, get_migrations/1]).
-export_type([migration/0, migration_error/0]).

-type migration() :: {migration, integer(), binary()}.

-type migration_error() :: {directory_not_exist, binary()} |
    {invalid_migration_name, binary()} |
    {invalid_migration_id, binary()} |
    {transaction_error, sqlight:error()} |
    {migrations_table_error, sqlight:error()} |
    {migration_script_error, integer(), sqlight:error()}.

-spec migration_error(migration_error()) -> fun((any()) -> migration_error()).
migration_error(Error) ->
    fun(_) -> Error end.

-spec migrate(list(migration()), sqlight:connection()) -> {ok, nil} |
    {error, migration_error()}.
migrate(Migrations, Connection) ->
    Transaction = (gleam@result:'try'(
        begin
            _pipe = sqlight:exec(<<"begin transaction;"/utf8>>, Connection),
            gleam@result:map_error(
                _pipe,
                fun(Field@0) -> {transaction_error, Field@0} end
            )
        end,
        fun(_) ->
            gleam@result:'try'(
                begin
                    _pipe@1 = sqlight:exec(
                        <<"create table if not exists storch_migrations (id integer, applied integer);"/utf8>>,
                        Connection
                    ),
                    gleam@result:map_error(
                        _pipe@1,
                        fun(Field@0) -> {migrations_table_error, Field@0} end
                    )
                end,
                fun(_) ->
                    Migrations_decoder = gleam@dynamic:tuple2(
                        fun gleam@dynamic:int/1,
                        fun sqlight:decode_bool/1
                    ),
                    Applications = gleam@list:try_each(
                        Migrations,
                        fun(Migration) ->
                            gleam@result:'try'(
                                begin
                                    _pipe@2 = sqlight:'query'(
                                        <<"select id, applied from storch_migrations where id = ?;"/utf8>>,
                                        Connection,
                                        [sqlight:int(
                                                erlang:element(2, Migration)
                                            )],
                                        Migrations_decoder
                                    ),
                                    gleam@result:map_error(
                                        _pipe@2,
                                        fun(Field@0) -> {migrations_table_error, Field@0} end
                                    )
                                end,
                                fun(Migrated) ->
                                    Already_applied = case Migrated of
                                        [] ->
                                            false;

                                        [{_, Applied}] ->
                                            Applied;

                                        _ ->
                                            erlang:error(#{gleam_error => panic,
                                                    message => <<"Multiple migrations with the same id in the storch migrations table"/utf8>>,
                                                    module => <<"storch"/utf8>>,
                                                    function => <<"migrate"/utf8>>,
                                                    line => 78})
                                    end,
                                    gleam@bool:guard(
                                        Already_applied,
                                        {ok, nil},
                                        fun() ->
                                            gleam@result:'try'(
                                                begin
                                                    _pipe@3 = sqlight:exec(
                                                        erlang:element(
                                                            3,
                                                            Migration
                                                        ),
                                                        Connection
                                                    ),
                                                    gleam@result:map_error(
                                                        _pipe@3,
                                                        fun(_capture) ->
                                                            {migration_script_error,
                                                                erlang:element(
                                                                    2,
                                                                    Migration
                                                                ),
                                                                _capture}
                                                        end
                                                    )
                                                end,
                                                fun(_) ->
                                                    gleam@result:'try'(
                                                        begin
                                                            _pipe@4 = sqlight:'query'(
                                                                <<"insert into storch_migrations (id, applied) values (?,?) returning *;"/utf8>>,
                                                                Connection,
                                                                [sqlight:int(
                                                                        erlang:element(
                                                                            2,
                                                                            Migration
                                                                        )
                                                                    ),
                                                                    sqlight:bool(
                                                                        true
                                                                    )],
                                                                Migrations_decoder
                                                            ),
                                                            gleam@result:map_error(
                                                                _pipe@4,
                                                                fun(Field@0) -> {migrations_table_error, Field@0} end
                                                            )
                                                        end,
                                                        fun(_) -> {ok, nil} end
                                                    )
                                                end
                                            )
                                        end
                                    )
                                end
                            )
                        end
                    ),
                    gleam@result:'try'(
                        Applications,
                        fun(_) ->
                            gleam@result:'try'(
                                begin
                                    _pipe@5 = sqlight:exec(
                                        <<"commit;"/utf8>>,
                                        Connection
                                    ),
                                    gleam@result:map_error(
                                        _pipe@5,
                                        fun(Field@0) -> {transaction_error, Field@0} end
                                    )
                                end,
                                fun(_) -> {ok, nil} end
                            )
                        end
                    )
                end
            )
        end
    )),
    case Transaction of
        {ok, _} ->
            {ok, nil};

        {error, Err} ->
            gleam@io:println(<<"error running migration"/utf8>>),
            gleam@io:debug(Err),
            gleam@io:println(<<"rolling back"/utf8>>),
            _ = sqlight:exec(<<"rollback;"/utf8>>, Connection),
            {error, Err}
    end.

-spec read_migrations(list(binary())) -> {ok, list({integer(), binary()})} |
    {error, migration_error()}.
read_migrations(Paths) ->
    gleam@list:try_map(
        Paths,
        fun(Path) ->
            Filename = filepath:base_name(Path),
            gleam@result:'try'(
                begin
                    _pipe = gleam@string:split_once(Filename, <<"_"/utf8>>),
                    gleam@result:map_error(
                        _pipe,
                        migration_error({invalid_migration_name, Filename})
                    )
                end,
                fun(_use0) ->
                    {Id, _} = _use0,
                    gleam@result:'try'(
                        begin
                            _pipe@1 = gleam@int:parse(Id),
                            gleam@result:map_error(
                                _pipe@1,
                                migration_error({invalid_migration_id, Id})
                            )
                        end,
                        fun(Id@1) ->
                            _assert_subject = simplifile:read(Path),
                            {ok, Contents} = case _assert_subject of
                                {ok, _} -> _assert_subject;
                                _assert_fail ->
                                    erlang:error(#{gleam_error => let_assert,
                                                message => <<"Assertion pattern match failed"/utf8>>,
                                                value => _assert_fail,
                                                module => <<"storch"/utf8>>,
                                                function => <<"read_migrations"/utf8>>,
                                                line => 152})
                            end,
                            {ok, {Id@1, Contents}}
                        end
                    )
                end
            )
        end
    ).

-spec get_migration_filenames(binary()) -> {ok, list(binary())} |
    {error, migration_error()}.
get_migration_filenames(Directory) ->
    gleam@result:'try'(
        begin
            _pipe = simplifile:is_directory(Directory),
            gleam@result:map_error(
                _pipe,
                migration_error({directory_not_exist, Directory})
            )
        end,
        fun(Is_dir) ->
            gleam@bool:guard(
                not Is_dir,
                {error, {directory_not_exist, Directory}},
                fun() ->
                    gleam@result:'try'(
                        begin
                            _pipe@1 = simplifile:get_files(Directory),
                            gleam@result:map_error(
                                _pipe@1,
                                migration_error(
                                    {directory_not_exist, Directory}
                                )
                            )
                        end,
                        fun(Filenames_raw) ->
                            _pipe@4 = gleam@list:map(
                                Filenames_raw,
                                fun(Path) ->
                                    gleam@result:'try'(
                                        filepath:extension(Path),
                                        fun(Extension) ->
                                            Base_path = filepath:directory_name(
                                                Path
                                            ),
                                            Filename = begin
                                                _pipe@2 = filepath:base_name(
                                                    Path
                                                ),
                                                filepath:strip_extension(
                                                    _pipe@2
                                                )
                                            end,
                                            gleam@bool:guard(
                                                Extension /= <<"sql"/utf8>>,
                                                {error, nil},
                                                fun() ->
                                                    gleam@bool:guard(
                                                        Base_path /= Directory,
                                                        {error, nil},
                                                        fun() ->
                                                            gleam@result:'try'(
                                                                gleam@string:split_once(
                                                                    Filename,
                                                                    <<"_"/utf8>>
                                                                ),
                                                                fun(_use0) ->
                                                                    {Numbers, _} = _use0,
                                                                    gleam@result:'try'(
                                                                        begin
                                                                            _pipe@3 = gleam@regex:from_string(
                                                                                <<"^[0-9]+$"/utf8>>
                                                                            ),
                                                                            gleam@result:nil_error(
                                                                                _pipe@3
                                                                            )
                                                                        end,
                                                                        fun(
                                                                            Regex
                                                                        ) ->
                                                                            gleam@bool:guard(
                                                                                not gleam@regex:check(
                                                                                    Regex,
                                                                                    Numbers
                                                                                ),
                                                                                {error,
                                                                                    nil},
                                                                                fun(
                                                                                    
                                                                                ) ->
                                                                                    {ok,
                                                                                        Path}
                                                                                end
                                                                            )
                                                                        end
                                                                    )
                                                                end
                                                            )
                                                        end
                                                    )
                                                end
                                            )
                                        end
                                    )
                                end
                            ),
                            _pipe@5 = gleam@result:values(_pipe@4),
                            {ok, _pipe@5}
                        end
                    )
                end
            )
        end
    ).

-spec get_migrations(binary()) -> {ok, list(migration())} |
    {error, migration_error()}.
get_migrations(Directory) ->
    gleam@result:'try'(
        get_migration_filenames(Directory),
        fun(Filenames) ->
            gleam@result:'try'(
                read_migrations(Filenames),
                fun(Raw_migrations) ->
                    _pipe = gleam@list:map(
                        Raw_migrations,
                        fun(Raw) ->
                            {migration,
                                erlang:element(1, Raw),
                                erlang:element(2, Raw)}
                        end
                    ),
                    _pipe@1 = gleam@list:sort(
                        _pipe,
                        fun(A, B) ->
                            gleam@int:compare(
                                erlang:element(2, A),
                                erlang:element(2, B)
                            )
                        end
                    ),
                    {ok, _pipe@1}
                end
            )
        end
    ).