-module(oaspec@codegen@writer).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/oaspec/codegen/writer.gleam").
-export([write_all/3, resolve_paths/2, expected_paths/2, output_dirs/1, error_to_string/1]).
-export_type([write_error/0]).

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

-type write_error() :: {directory_create_error, binary(), binary()} |
    {file_write_error, binary(), binary()}.

-file("src/oaspec/codegen/writer.gleam", 57).
?DOC(" Ensure a directory exists, creating it if necessary.\n").
-spec ensure_directory(binary()) -> {ok, nil} | {error, write_error()}.
ensure_directory(Path) ->
    _pipe = simplifile:create_directory_all(Path),
    gleam@result:map_error(
        _pipe,
        fun(Err) ->
            {directory_create_error,
                Path,
                <<"Failed to create directory: "/utf8,
                    (simplifile:describe_error(Err))/binary>>}
        end
    ).

-file("src/oaspec/codegen/writer.gleam", 73).
?DOC(
    " Write a list of generated files to a directory.\n"
    "\n"
    " Issue #247: files marked `SkipIfExists` (currently `handlers.gleam`)\n"
    " are written only on first generation. If the file already exists on\n"
    " disk, it is left alone — the user owns the contents and the\n"
    " generator must not clobber their implementation.\n"
).
-spec write_files(
    list(oaspec@codegen@context:generated_file()),
    binary(),
    list(binary()),
    fun((binary()) -> nil)
) -> {ok, list(binary())} | {error, write_error()}.
write_files(Files, Base_path, Written, On_write) ->
    gleam@list:try_fold(
        Files,
        Written,
        fun(Acc, File) ->
            Full_path = <<<<Base_path/binary, "/"/utf8>>/binary,
                (erlang:element(2, File))/binary>>,
            case {erlang:element(5, File), simplifile_erl:is_file(Full_path)} of
                {skip_if_exists, {ok, true}} ->
                    {ok, Acc};

                {_, _} ->
                    gleam@result:'try'(
                        begin
                            _pipe = simplifile:write(
                                Full_path,
                                erlang:element(3, File)
                            ),
                            gleam@result:map_error(
                                _pipe,
                                fun(Err) ->
                                    {file_write_error,
                                        Full_path,
                                        <<"Failed to write file: "/utf8,
                                            (simplifile:describe_error(Err))/binary>>}
                                end
                            )
                        end,
                        fun(_) ->
                            On_write(Full_path),
                            {ok, [Full_path | Acc]}
                        end
                    )
            end
        end
    ).

-file("src/oaspec/codegen/writer.gleam", 14).
?DOC(" Write pre-generated files to disk based on configuration.\n").
-spec write_all(
    list(oaspec@codegen@context:generated_file()),
    oaspec@config:config(),
    fun((binary()) -> nil)
) -> {ok, list(binary())} | {error, write_error()}.
write_all(Files, Cfg, On_write) ->
    Shared_files = gleam@list:filter(
        Files,
        fun(F) -> erlang:element(4, F) =:= shared_target end
    ),
    Server_files = gleam@list:filter(
        Files,
        fun(F@1) -> erlang:element(4, F@1) =:= server_target end
    ),
    Client_files = gleam@list:filter(
        Files,
        fun(F@2) -> erlang:element(4, F@2) =:= client_target end
    ),
    Server_path = oaspec@config:output_server(Cfg),
    Client_path = oaspec@config:output_client(Cfg),
    Written_files = [],
    gleam@result:'try'(case oaspec@config:mode(Cfg) of
            server ->
                gleam@result:'try'(
                    ensure_directory(Server_path),
                    fun(_) ->
                        _pipe = write_files(
                            Shared_files,
                            Server_path,
                            Written_files,
                            On_write
                        ),
                        gleam@result:'try'(
                            _pipe,
                            fun(W) ->
                                write_files(
                                    Server_files,
                                    Server_path,
                                    W,
                                    On_write
                                )
                            end
                        )
                    end
                );

            both ->
                gleam@result:'try'(
                    ensure_directory(Server_path),
                    fun(_) ->
                        _pipe = write_files(
                            Shared_files,
                            Server_path,
                            Written_files,
                            On_write
                        ),
                        gleam@result:'try'(
                            _pipe,
                            fun(W) ->
                                write_files(
                                    Server_files,
                                    Server_path,
                                    W,
                                    On_write
                                )
                            end
                        )
                    end
                );

            client ->
                {ok, Written_files}
        end, fun(Written_files@1) ->
            gleam@result:'try'(case oaspec@config:mode(Cfg) of
                    client ->
                        gleam@result:'try'(
                            ensure_directory(Client_path),
                            fun(_) ->
                                _pipe@1 = write_files(
                                    Shared_files,
                                    Client_path,
                                    Written_files@1,
                                    On_write
                                ),
                                gleam@result:'try'(
                                    _pipe@1,
                                    fun(W@1) ->
                                        write_files(
                                            Client_files,
                                            Client_path,
                                            W@1,
                                            On_write
                                        )
                                    end
                                )
                            end
                        );

                    both ->
                        gleam@result:'try'(
                            ensure_directory(Client_path),
                            fun(_) ->
                                _pipe@1 = write_files(
                                    Shared_files,
                                    Client_path,
                                    Written_files@1,
                                    On_write
                                ),
                                gleam@result:'try'(
                                    _pipe@1,
                                    fun(W@1) ->
                                        write_files(
                                            Client_files,
                                            Client_path,
                                            W@1,
                                            On_write
                                        )
                                    end
                                )
                            end
                        );

                    server ->
                        {ok, Written_files@1}
                end, fun(Written_files@2) -> {ok, Written_files@2} end)
        end).

-file("src/oaspec/codegen/writer.gleam", 112).
?DOC(
    " Resolve generated files to their full output paths and content.\n"
    " Used by --check to compare against existing files without writing.\n"
    "\n"
    " Issue #247: `SkipIfExists` files (e.g. user-owned `handlers.gleam`)\n"
    " are dropped from the result. `--check` is meant to flag drift in\n"
    " generator-owned files; user-edited files are expected to differ\n"
    " from the bootstrap stub and should not be reported as out-of-date.\n"
).
-spec resolve_paths(
    list(oaspec@codegen@context:generated_file()),
    oaspec@config:config()
) -> list({binary(), binary()}).
resolve_paths(Files, Cfg) ->
    Files@1 = gleam@list:filter(
        Files,
        fun(F) -> erlang:element(5, F) /= skip_if_exists end
    ),
    Shared_files = gleam@list:filter(
        Files@1,
        fun(F@1) -> erlang:element(4, F@1) =:= shared_target end
    ),
    Server_files = gleam@list:filter(
        Files@1,
        fun(F@2) -> erlang:element(4, F@2) =:= server_target end
    ),
    Client_files = gleam@list:filter(
        Files@1,
        fun(F@3) -> erlang:element(4, F@3) =:= client_target end
    ),
    Server_path = oaspec@config:output_server(Cfg),
    Client_path = oaspec@config:output_client(Cfg),
    Server_entries = case oaspec@config:mode(Cfg) of
        server ->
            gleam@list:map(
                lists:append(Shared_files, Server_files),
                fun(F@4) ->
                    {<<<<Server_path/binary, "/"/utf8>>/binary,
                            (erlang:element(2, F@4))/binary>>,
                        erlang:element(3, F@4)}
                end
            );

        both ->
            gleam@list:map(
                lists:append(Shared_files, Server_files),
                fun(F@4) ->
                    {<<<<Server_path/binary, "/"/utf8>>/binary,
                            (erlang:element(2, F@4))/binary>>,
                        erlang:element(3, F@4)}
                end
            );

        client ->
            []
    end,
    Client_entries = case oaspec@config:mode(Cfg) of
        client ->
            gleam@list:map(
                lists:append(Shared_files, Client_files),
                fun(F@5) ->
                    {<<<<Client_path/binary, "/"/utf8>>/binary,
                            (erlang:element(2, F@5))/binary>>,
                        erlang:element(3, F@5)}
                end
            );

        both ->
            gleam@list:map(
                lists:append(Shared_files, Client_files),
                fun(F@5) ->
                    {<<<<Client_path/binary, "/"/utf8>>/binary,
                            (erlang:element(2, F@5))/binary>>,
                        erlang:element(3, F@5)}
                end
            );

        server ->
            []
    end,
    lists:append(Server_entries, Client_entries).

-file("src/oaspec/codegen/writer.gleam", 150).
?DOC(
    " Every file path the generator would write for the given config — including\n"
    " `SkipIfExists` files. Used by `--check` to keep user-owned `handlers.gleam`\n"
    " off the orphan list while still excluding it from byte-comparison drift\n"
    " reports (`resolve_paths` drops `SkipIfExists` entries).\n"
).
-spec expected_paths(
    list(oaspec@codegen@context:generated_file()),
    oaspec@config:config()
) -> list(binary()).
expected_paths(Files, Cfg) ->
    Shared_files = gleam@list:filter(
        Files,
        fun(F) -> erlang:element(4, F) =:= shared_target end
    ),
    Server_files = gleam@list:filter(
        Files,
        fun(F@1) -> erlang:element(4, F@1) =:= server_target end
    ),
    Client_files = gleam@list:filter(
        Files,
        fun(F@2) -> erlang:element(4, F@2) =:= client_target end
    ),
    Server_path = oaspec@config:output_server(Cfg),
    Client_path = oaspec@config:output_client(Cfg),
    Server_entries = case oaspec@config:mode(Cfg) of
        server ->
            gleam@list:map(
                lists:append(Shared_files, Server_files),
                fun(F@3) ->
                    <<<<Server_path/binary, "/"/utf8>>/binary,
                        (erlang:element(2, F@3))/binary>>
                end
            );

        both ->
            gleam@list:map(
                lists:append(Shared_files, Server_files),
                fun(F@3) ->
                    <<<<Server_path/binary, "/"/utf8>>/binary,
                        (erlang:element(2, F@3))/binary>>
                end
            );

        client ->
            []
    end,
    Client_entries = case oaspec@config:mode(Cfg) of
        client ->
            gleam@list:map(
                lists:append(Shared_files, Client_files),
                fun(F@4) ->
                    <<<<Client_path/binary, "/"/utf8>>/binary,
                        (erlang:element(2, F@4))/binary>>
                end
            );

        both ->
            gleam@list:map(
                lists:append(Shared_files, Client_files),
                fun(F@4) ->
                    <<<<Client_path/binary, "/"/utf8>>/binary,
                        (erlang:element(2, F@4))/binary>>
                end
            );

        server ->
            []
    end,
    lists:append(Server_entries, Client_entries).

-file("src/oaspec/codegen/writer.gleam", 184).
?DOC(" Return the output directories that would be written to for the given config.\n").
-spec output_dirs(oaspec@config:config()) -> list(binary()).
output_dirs(Cfg) ->
    case oaspec@config:mode(Cfg) of
        server ->
            [oaspec@config:output_server(Cfg)];

        client ->
            [oaspec@config:output_client(Cfg)];

        both ->
            [oaspec@config:output_server(Cfg), oaspec@config:output_client(Cfg)]
    end.

-file("src/oaspec/codegen/writer.gleam", 193).
?DOC(" Convert a write error to a human-readable string.\n").
-spec error_to_string(write_error()) -> binary().
error_to_string(Error) ->
    case Error of
        {directory_create_error, Path, Detail} ->
            <<<<<<"Failed to create directory "/utf8, Path/binary>>/binary,
                    ": "/utf8>>/binary,
                Detail/binary>>;

        {file_write_error, Path@1, Detail@1} ->
            <<<<<<"Failed to write file "/utf8, Path@1/binary>>/binary,
                    ": "/utf8>>/binary,
                Detail@1/binary>>
    end.