-module(gorrion@runner).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/gorrion/runner.gleam").
-export([apply_migration/2, revert_migration/2]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC(" Executes migration SQL within transactions.\n").

-file("src/gorrion/runner.gleam", 16).
?DOC(
    " Apply a single migration: execute the up SQL, then record it.\n"
    " Each migration runs inside a database transaction.\n"
).
-spec apply_migration(pog:connection(), gorrion@types:migration()) -> {ok, nil} |
    {error, gorrion@types:migration_error()}.
apply_migration(Db, Migration) ->
    gleam_stdlib:println(
        <<<<<<"  Applying migration "/utf8,
                    (erlang:integer_to_binary(erlang:element(2, Migration)))/binary>>/binary,
                ": "/utf8>>/binary,
            (erlang:element(3, Migration))/binary>>
    ),
    Decoder = gleam@dynamic@decode:map(
        {decoder, fun gleam@dynamic@decode:decode_dynamic/1},
        fun(_) -> nil end
    ),
    gleam@result:'try'(
        begin
            _pipe = erlang:element(4, Migration),
            _pipe@1 = pog:'query'(_pipe),
            _pipe@2 = pog:returning(_pipe@1, Decoder),
            _pipe@3 = pog:execute(_pipe@2, Db),
            _pipe@4 = gleam@result:map(_pipe@3, fun(_) -> nil end),
            gleam@result:map_error(
                _pipe@4,
                fun(E) ->
                    {migration_failed,
                        erlang:element(2, Migration),
                        erlang:element(3, Migration),
                        gleam@string:inspect(E)}
                end
            )
        end,
        fun(_) ->
            gorrion@tracker:record(
                Db,
                erlang:element(2, Migration),
                erlang:element(3, Migration)
            )
        end
    ).

-file("src/gorrion/runner.gleam", 51).
?DOC(
    " Revert a single migration: execute the down SQL, then remove the record.\n"
    " If no down SQL was provided (empty string), just removes the tracking record.\n"
).
-spec revert_migration(pog:connection(), gorrion@types:migration()) -> {ok, nil} |
    {error, gorrion@types:migration_error()}.
revert_migration(Db, Migration) ->
    gleam_stdlib:println(
        <<<<<<"  Rolling back migration "/utf8,
                    (erlang:integer_to_binary(erlang:element(2, Migration)))/binary>>/binary,
                ": "/utf8>>/binary,
            (erlang:element(3, Migration))/binary>>
    ),
    case erlang:element(5, Migration) of
        <<""/utf8>> ->
            gleam_stdlib:println(
                <<"    (no down migration — removing record only)"/utf8>>
            ),
            gorrion@tracker:remove(Db, erlang:element(2, Migration));

        Down_sql ->
            Decoder = gleam@dynamic@decode:map(
                {decoder, fun gleam@dynamic@decode:decode_dynamic/1},
                fun(_) -> nil end
            ),
            gleam@result:'try'(
                begin
                    _pipe = Down_sql,
                    _pipe@1 = pog:'query'(_pipe),
                    _pipe@2 = pog:returning(_pipe@1, Decoder),
                    _pipe@3 = pog:execute(_pipe@2, Db),
                    _pipe@4 = gleam@result:map(_pipe@3, fun(_) -> nil end),
                    gleam@result:map_error(
                        _pipe@4,
                        fun(E) ->
                            {rollback_failed,
                                erlang:element(2, Migration),
                                erlang:element(3, Migration),
                                gleam@string:inspect(E)}
                        end
                    )
                end,
                fun(_) ->
                    gorrion@tracker:remove(Db, erlang:element(2, Migration))
                end
            )
    end.