-module(gleeth@events).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/gleeth/events.gleam").
-export([decode_logs/2, get_events/5, get_events_by_name/6]).
-export_type([event_result/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.

?MODULEDOC(
    " Query and decode contract events in a single call.\n"
    "\n"
    " Combines `methods.get_logs` with ABI event decoding so you don't have\n"
    " to manually match topic hashes and decode parameters.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let assert Ok(abi) = json.parse_abi(erc20_abi_json)\n"
    " let assert Ok(decoded) = events.get_events(\n"
    "   provider,\n"
    "   \"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48\",\n"
    "   abi,\n"
    "   \"0x100000\",\n"
    "   \"latest\",\n"
    " )\n"
    " // decoded: List(EventResult) - each with event name and typed params\n"
    " ```\n"
).

-type event_result() :: {decoded,
        gleeth@ethereum@abi@events:decoded_log(),
        gleeth@ethereum@types:log()} |
    {unknown, gleeth@ethereum@types:log()}.

-file("src/gleeth/events.gleam", 100).
?DOC(
    " Decode a list of raw logs against an ABI. Useful when you already\n"
    " have logs from another source (e.g. a transaction receipt).\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let results = events.decode_logs(receipt.logs, abi)\n"
    " ```\n"
).
-spec decode_logs(
    list(gleeth@ethereum@types:log()),
    list(gleeth@ethereum@abi@json:abi_entry())
) -> list(event_result()).
decode_logs(Logs, Abi) ->
    gleam@list:map(
        Logs,
        fun(Log) -> case gleeth@ethereum@abi@events:decode_log(Log, Abi) of
                {ok, Decoded} ->
                    {decoded, Decoded, Log};

                {error, _} ->
                    {unknown, Log}
            end end
    ).

-file("src/gleeth/events.gleam", 46).
?DOC(
    " Query logs for a contract and decode them against the provided ABI.\n"
    " Logs that match an event in the ABI are decoded; unmatched logs are\n"
    " returned as `Unknown` so no data is lost.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let assert Ok(events) = events.get_events(\n"
    "   provider, \"0xA0b8...\", abi, \"0x100000\", \"latest\",\n"
    " )\n"
    " ```\n"
).
-spec get_events(
    gleeth@provider:provider(),
    binary(),
    list(gleeth@ethereum@abi@json:abi_entry()),
    binary(),
    binary()
) -> {ok, list(event_result())} | {error, gleeth@rpc@types:gleeth_error()}.
get_events(Provider, Address, Abi, From_block, To_block) ->
    gleam@result:'try'(
        gleeth@rpc@methods:get_logs(Provider, From_block, To_block, Address, []),
        fun(Logs) -> {ok, decode_logs(Logs, Abi)} end
    ).

-file("src/gleeth/events.gleam", 119).
-spec compute_event_topic(list(gleeth@ethereum@abi@json:abi_entry()), binary()) -> binary().
compute_event_topic(Abi, Event_name) ->
    Found = gleam@list:find(Abi, fun(Entry) -> case Entry of
                {event_entry, Name, _} ->
                    Name =:= Event_name;

                _ ->
                    false
            end end),
    case Found of
        {ok, {event_entry, Name@1, Inputs}} ->
            Types = gleam@list:map(Inputs, fun(P) -> erlang:element(3, P) end),
            gleeth@ethereum@abi@events:event_topic_hex(Name@1, Types);

        _ ->
            <<""/utf8>>
    end.

-file("src/gleeth/events.gleam", 69).
?DOC(
    " Query logs for a specific event name. Filters by the event's topic0 hash,\n"
    " so only matching logs are returned from the RPC.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " let assert Ok(transfers) = events.get_events_by_name(\n"
    "   provider, \"0xA0b8...\", abi, \"Transfer\", \"0x100000\", \"latest\",\n"
    " )\n"
    " ```\n"
).
-spec get_events_by_name(
    gleeth@provider:provider(),
    binary(),
    list(gleeth@ethereum@abi@json:abi_entry()),
    binary(),
    binary(),
    binary()
) -> {ok, list(event_result())} | {error, gleeth@rpc@types:gleeth_error()}.
get_events_by_name(Provider, Address, Abi, Event_name, From_block, To_block) ->
    Topic0 = compute_event_topic(Abi, Event_name),
    Topics = case Topic0 of
        <<""/utf8>> ->
            [];

        T ->
            [T]
    end,
    gleam@result:'try'(
        gleeth@rpc@methods:get_logs(
            Provider,
            From_block,
            To_block,
            Address,
            Topics
        ),
        fun(Logs) -> {ok, decode_logs(Logs, Abi)} end
    ).