-module(database).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/database.gleam").
-export([create_dets_table/2, create_table/2, create_ets_table/1, transaction/2, upsert/3, insert/2, update/3, delete/2, find/2, drop_table/1, select/2, migrate_dets/2, field/3, enum/2]).
-export_type([table_attributes/0, continue/0, table_ref/1, transaction/1, table/1, file_error/0, find_error/0, transaction_error/1, select_error/0, migrate_options/1]).

-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(
    " An outrageously simple set of functions to interact with the BEAM\n"
    " ETS (Erlang Term Storage) and DETS (Disk-based ETS) API.\n"
    " \n"
    " Good for small projects and POCs.\n"
    "\n"
    "\n"
    " This project DOES NOT intend to serve as direct bindings to the \n"
    " DETS API, but rather to interact with it in a gleamy way:\n"
    "   1. with a simple and concise interface;\n"
    "   2. type-safely;\n"
    "   3. no unexpected crashes, all errors are values.\n"
).

-type table_attributes() :: {file, gleam@erlang@charlist:charlist()} |
    {type, table_attributes()} |
    {keypos, integer()} |
    public |
    set.

-type continue() :: continue.

-type table_ref(DXH) :: any() | {gleam_phantom, DXH}.

-opaque transaction(DXI) :: {disk_transaction,
        table_ref({binary(), DXI}),
        gleam@dynamic@decode:decoder(DXI)} |
    {memory_transaction, table_ref({binary(), DXI})}.

-opaque table(DXJ) :: {disk_table,
        gleam@erlang@atom:atom_(),
        list(table_attributes()),
        gleam@erlang@charlist:charlist(),
        gleam@dynamic@decode:decoder(DXJ)} |
    {memory_table, table_ref({binary(), DXJ})}.

-type file_error() :: unable_to_open | unable_to_close.

-type find_error() :: not_found |
    {unable_to_decode, list(gleam@dynamic@decode:decode_error())}.

-type transaction_error(DXK) :: {file_error, file_error()} | {operation, DXK}.

-type select_error() :: badarg.

-type migrate_options(DXL) :: {update, DXL} | keep | delete.

-file("src/database.gleam", 164).
?DOC(
    " Creats a DETS table (on disk!).\n"
    "\n"
    " If no .dets file exists for the provided definition, creates one.\n"
    " Otherwise, just checks whether the file is accessible and not\n"
    " corrupted.\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn start_database() {\n"
    "   let table_decoder = {\n"
    "     use name <- database.field(0, decode.string)\n"
    "     use animal <- database.field(1, my_animal_decoder)\n"
    "     decode.success(Pet(name:, animal:))\n"
    "   }\n"
    "   let table_name = atom.create(\"pets\")\n"
    "   database.create_dets_table(name: table_name, decode_with: table_decoder)\n"
    "   // -> Ok(Table(Pet))\n"
    " }\n"
    " ```\n"
).
-spec create_dets_table(
    gleam@erlang@atom:atom_(),
    gleam@dynamic@decode:decoder(EAA)
) -> {ok, table(EAA)} | {error, file_error()}.
create_dets_table(Name, Decoder) ->
    Path = unicode:characters_to_list(
        <<(erlang:atom_to_binary(Name))/binary, ".dets"/utf8>>
    ),
    Att = [{file, Path}, {type, set}, {keypos, 1}],
    case dets:open_file(Name, Att) of
        {ok, Tab} ->
            case dets:close(Tab) of
                {error, _} ->
                    {error, unable_to_close};

                _ ->
                    {ok, {disk_table, Name, Att, Path, Decoder}}
            end;

        {error, _} ->
            {error, unable_to_open}
    end.

-file("src/database.gleam", 184).
-spec create_table(gleam@erlang@atom:atom_(), gleam@dynamic@decode:decoder(EAF)) -> {ok,
        table(EAF)} |
    {error, file_error()}.
create_table(Name, Decoder) ->
    create_dets_table(Name, Decoder).

-file("src/database.gleam", 203).
?DOC(
    " Creats a ETS table (in memory!).\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn start_database() {\n"
    "   let table_name = atom.create(\"pets\")\n"
    "   database.create_ets_table(name: table_name)\n"
    "   // -> Table(a)\n"
    " }\n"
    " ```\n"
).
-spec create_ets_table(gleam@erlang@atom:atom_()) -> table(any()).
create_ets_table(Name) ->
    Att = [set, public, {keypos, 1}],
    {memory_table, ets:new(Name, Att)}.

-file("src/database.gleam", 237).
?DOC(
    " Allows you to interact with the table.\n"
    "\n"
    " For DETS tables, it opens and locks the .dets file, then execute your operations.\n"
    " Once the operations are done, it writes the changes into the file,\n"
    " closes and releases it.\n"
    " For ETS tables, it freezes the content of the table, then execute your operations.\n"
    " Once the operations are done, it pushes the possible new changes (from other parts of your code)\n"
    " into it and releases it.\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn is_pet_registered(table: Table(Pet), pet_id: String) {\n"
    "   use ref <- database.transaction(table)\n"
    "   case database.find(ref, pet_id) {\n"
    "     Ok(_) -> True\n"
    "     Error(_) -> False\n"
    "   }\n"
    " }\n"
    " ```\n"
).
-spec transaction(
    table(EAM),
    fun((transaction(EAM)) -> {ok, EAP} | {error, EAQ})
) -> {ok, EAP} | {error, transaction_error(EAQ)}.
transaction(Table, Procedure) ->
    case Table of
        {disk_table, Tabname, Attributes, _, _} ->
            case dets:open_file(Tabname, Attributes) of
                {error, _} ->
                    {error, {file_error, unable_to_open}};

                {ok, Ref} ->
                    Resp = Procedure(
                        {disk_transaction, Ref, erlang:element(5, Table)}
                    ),
                    case dets:close(Ref) of
                        {error, _} ->
                            {error, {file_error, unable_to_close}};

                        _ ->
                            gleam@result:map_error(
                                Resp,
                                fun(Field@0) -> {operation, Field@0} end
                            )
                    end
            end;

        {memory_table, Ref@1} ->
            ets:safe_fixtable(Ref@1, true),
            Resp@1 = Procedure({memory_transaction, Ref@1}),
            ets:safe_fixtable(Ref@1, false),
            gleam@result:map_error(
                Resp@1,
                fun(Field@0) -> {operation, Field@0} end
            )
    end.

-file("src/database.gleam", 289).
?DOC(
    " Inserts a value into a table with a specific id. If the id already exists, the value is overwritten.\n"
    "\n"
    " # Example\n"
    " ```gleam\n"
    " pub fn save_user(table: Table(User), user: User) {\n"
    "   use ref <- database.transaction(table)\n"
    "   database.upsert(ref, user.email, user)\n"
    " }\n"
    " ```\n"
).
-spec upsert(transaction(EBA), binary(), EBA) -> {ok, binary()} | {error, nil}.
upsert(Transac, Id, Value) ->
    case Transac of
        {disk_transaction, Ref, _} ->
            case dets:insert(Ref, {Id, Value}) of
                {error, _} ->
                    {error, nil};

                _ ->
                    {ok, Id}
            end;

        {memory_transaction, Ref@1} ->
            case ets:insert(Ref@1, {Id, Value}) of
                false ->
                    {error, nil};

                true ->
                    {ok, Id}
            end
    end.

-file("src/database.gleam", 274).
?DOC(
    " Inserts a value into a table and return their generated id.\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn new_pet(table: Table(Pet), animal: Animal, name: String) {\n"
    "   let pet = Pet(name, animal)\n"
    "   use ref <- database.transaction(table)\n"
    "   database.insert(ref, pet)  \n"
    " }\n"
    " ```\n"
).
-spec insert(transaction(EAW), EAW) -> {ok, binary()} | {error, nil}.
insert(Transac, Value) ->
    Id = begin
        _pipe = crypto:strong_rand_bytes(16),
        gleam@bit_array:base64_url_encode(_pipe, false)
    end,
    upsert(Transac, Id, Value).

-file("src/database.gleam", 320).
?DOC(
    " Updates a value in a table.\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn rename_pet(table: Table(Pet) id: String, pet: Pet, new_name: String) {\n"
    "   use transac <- database.transaction(table)\n"
    "   let pet = Pet(new_name, pet.animal)\n"
    "   database.update(transac, id, pet)\n"
    " }\n"
    " ```\n"
).
-spec update(transaction(EBE), binary(), EBE) -> {ok, binary()} | {error, nil}.
update(Transac, Id, Value) ->
    case Transac of
        {disk_transaction, Ref, _} ->
            case dets:lookup(Ref, Id) of
                [_] ->
                    upsert(Transac, Id, Value);

                _ ->
                    {error, nil}
            end;

        {memory_transaction, Ref@1} ->
            case ets:lookup(Ref@1, Id) of
                [_] ->
                    upsert(Transac, Id, Value);

                _ ->
                    {error, nil}
            end
    end.

-file("src/database.gleam", 350).
?DOC(
    " Deletes a value from a table.\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn delete_pet(table: Table(Pet) pet_id: String) {\n"
    "   use ref <- database.transaction(table)\n"
    "   database.delete(ref, pet_id)\n"
    " }\n"
    " ```\n"
).
-spec delete(transaction(any()), binary()) -> {ok, nil} | {error, nil}.
delete(Transac, Id) ->
    case Transac of
        {disk_transaction, Ref, _} ->
            case dets:delete(Ref, Id) of
                {error, _} ->
                    {error, nil};

                _ ->
                    {ok, nil}
            end;

        {memory_transaction, Ref@1} ->
            case ets:delete(Ref@1, Id) of
                false ->
                    {error, nil};

                true ->
                    {ok, nil}
            end
    end.

-file("src/database.gleam", 380).
?DOC(
    " Finds a value by its index\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn play_with_pluto(table: Table(Pet)) {\n"
    "   use ref <- database.transaction(table)\n"
    "   let resp = database.find(ref, known_pluto_id)\n"
    "   case resp {\n"
    "     Error(_) -> Error(PlutoNotFoundBlameTheAstronomers)\n"
    "     Ok(pluto) -> Ok(play_with(pluto))\n"
    "   }\n"
    " }\n"
    " ```\n"
).
-spec find(transaction(EBM), binary()) -> {ok, EBM} | {error, find_error()}.
find(Transac, Id) ->
    case Transac of
        {disk_transaction, Ref, Decoder} ->
            case dets:lookup(Ref, Id) of
                [{_, Resp}] ->
                    case gleam@dynamic@decode:run(Resp, Decoder) of
                        {ok, Val} ->
                            {ok, Val};

                        {error, Errors} ->
                            {error, {unable_to_decode, Errors}}
                    end;

                _ ->
                    {error, not_found}
            end;

        {memory_transaction, Ref@1} ->
            case ets:lookup(Ref@1, Id) of
                [{_, Val@1}] ->
                    {ok, Val@1};

                _ ->
                    {error, not_found}
            end
    end.

-file("src/database.gleam", 415).
?DOC(
    " Deletes the entire table file\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn destroy_all_pets(table: Table(Pet), password: String) {\n"
    "   case password {\n"
    "     \"Yes, I am evil.\" -> {\n"
    "       database.drop_table(table)\n"
    "       Ok(Nil)\n"
    "     }\n"
    "     _ -> Error(WrongPassword)\n"
    "   }\n"
    " }\n"
    " ```\n"
).
-spec drop_table(table(any())) -> {ok, nil} | {error, nil}.
drop_table(Table) ->
    case Table of
        {disk_table, _, _, Path, _} ->
            case file:delete(Path) of
                {error, _} ->
                    {error, nil};

                _ ->
                    {ok, nil}
            end;

        {memory_table, Ref} ->
            case ets:delete(Ref) of
                false ->
                    {error, nil};

                true ->
                    {ok, nil}
            end
    end.

-file("src/database.gleam", 466).
?DOC(
    " Searches for somethig on the table.\n"
    "\n"
    " The native functions used to select values from tables (`ets|dets:select|match_object`)\n"
    " rely on Erlang's extremely loose type system, which goes against both Gleam's and this projects's principles.\n"
    " So, in order to make it functional (and performatic), some compromises had to be done.\n"
    " Most notably, this function receives an untyped (unused generic) parameter, which is a tuple with the patterns to be matched,\n"
    " said patterns can be values to be pattern-matched or functions that return said values, as shown below.\n"
    " For more examples, access the `database_test.gleam` file\n"
    "\n"
    " Don't worry, while the parameters for the result might be a bit loosey, its return is perfectly type safe,\n"
    " as enforced by the Gleam compiler (on both ETS and DETS modes) and the `decode` API (only in DETS mode)\n"
    "\n"
    " # Example\n"
    " \n"
    " ```gleam\n"
    " pub fn fetch_all_parrots(table: Table(Pet)) {\n"
    "   use ref <- database.transaction(table)\n"
    "   let _ = database.insert(ref, Parrot(\"Kiwi\"))\n"
    "   let _ = database.insert(ref, Cat(\"Hulu\"))\n"
    "   let _ = database.insert(ref, Parrot(\"Tata\"))\n"
    "   let _ = database.insert(ref, Dog(\"Mina\"))\n"
    "   database.select(ref, #(Parrot(_)))\n"
    " }\n"
    " ```\n"
    "\n"
    " # IMPORTANT\n"
    " **By default, DETS and ETS tables are not sorted in any deterministic way, so\n"
    " never assume that the last value inserted will be the last\n"
    " one on the table.**\n"
).
-spec select(transaction(EBU), any()) -> {ok, list({binary(), EBU})} |
    {error, select_error()}.
select(Transac, Patterns) ->
    case database_ffi:format_select_pattern(Patterns) of
        {error, _} ->
            {error, badarg};

        {ok, Patterns@1} ->
            case Transac of
                {memory_transaction, Ref} ->
                    {ok, ets:select(Ref, Patterns@1)};

                {disk_transaction, Ref@1, Decoder} ->
                    case database_ffi:safe_dets_select(Ref@1, Patterns@1) of
                        {error, _} ->
                            {ok, []};

                        {ok, Dyn_values} ->
                            {ok,
                                gleam@list:filter_map(
                                    Dyn_values,
                                    fun(Tpl) ->
                                        {Id, Dyn_value} = Tpl,
                                        case gleam@dynamic@decode:run(
                                            Dyn_value,
                                            Decoder
                                        ) of
                                            {ok, Value} ->
                                                {ok, {Id, Value}};

                                            {error, _} ->
                                                {error, nil}
                                        end
                                    end
                                )}
                    end
            end
    end.

-file("src/database.gleam", 530).
?DOC(
    " Migrates an DETS table to a new structure (does nothing to ETS tables, since those only exist in runtime).\n"
    " When the type stored in the table changes, this function\n"
    " allows you to update the table to the new structure.\n"
    " \n"
    " This function will error if you try to use it on an ETS table.\n"
    "\n"
    " # Example\n"
    "\n"
    " ```gleam\n"
    " pub fn migrate_pets(table: Table(Pet)) {\n"
    "   use value <- database.migrate(table)\n"
    "   case decode.run(value, my_pet_decoder()) {\n"
    "     Ok(pet) -> Update(pet)\n"
    "     _ -> Delete\n"
    "   } \n"
    " }\n"
    " ```\n"
).
-spec migrate_dets(
    transaction(ECA),
    fun((gleam@dynamic:dynamic_()) -> migrate_options(ECA))
) -> {ok, nil} | {error, nil}.
migrate_dets(Transac, Migration) ->
    case Transac of
        {memory_transaction, _} ->
            {error, nil};

        {disk_transaction, Ref, _} ->
            Func = fun(Tab_value) ->
                {Id, Dyn_value} = Tab_value,
                case Migration(Dyn_value) of
                    {update, New_value} ->
                        _ = dets:insert(Ref, {Id, New_value}),
                        continue;

                    delete ->
                        _ = dets:delete(Ref, Id),
                        continue;

                    keep ->
                        continue
                end
            end,
            _ = dets:traverse(Ref, Func),
            {ok, nil}
    end.

-file("src/database.gleam", 569).
?DOC(
    " Field decoder\n"
    " \n"
    " # Example\n"
    " \n"
    " ```gleam\n"
    " let decoder = {\n"
    "   use name <- database.field(0, decode.string)\n"
    "   use animal <- database.field(1, my_animal_decoder)\n"
    "   decode.success(Pet(name:, animal:))\n"
    " }\n"
    " ```\n"
).
-spec field(
    integer(),
    gleam@dynamic@decode:decoder(ECF),
    fun((ECF) -> gleam@dynamic@decode:decoder(ECH))
) -> gleam@dynamic@decode:decoder(ECH).
field(Field_index, Field_decoder, Next) ->
    gleam@dynamic@decode:field(Field_index + 1, Field_decoder, Next).

-file("src/database.gleam", 590).
?DOC(
    " Enum decoder\n"
    " \n"
    " # Example\n"
    " \n"
    " ```gleam\n"
    " let decoder = {\n"
    "   use name <- database.field(0, decode.string)\n"
    "   use animal <- database.field(1, database.enum([Dog, Cat, Parrot], Dog))\n"
    "   decode.success(Pet(name:, animal:))\n"
    " }\n"
    " ```\n"
).
-spec enum(list(ECK), ECK) -> gleam@dynamic@decode:decoder(ECK).
enum(Values, Zero_value) ->
    gleam@dynamic@decode:new_primitive_decoder(
        <<"Enum"/utf8>>,
        fun(Data) ->
            case gleam@list:find(
                Values,
                fun(_capture) -> database_ffi:compare(_capture, Data) end
            ) of
                {ok, Value} ->
                    {ok, Value};

                {error, _} ->
                    {error, Zero_value}
            end
        end
    ).