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

-export([new/1, s/2, d/2, f/2, try_fmt/2, write/3, print/2, println/2, writef/2, printf/1, printlnf/1, fmt/2, try_build/1, build/1]).
-export_type([fmt_error/0, fmt/0, formatter/0]).

-type fmt_error() :: incorrect_value_type | too_many_values | not_enough_values.

-type fmt() :: {s, binary()} | {d, integer()} | {f, float()}.

-type formatter() :: {formatter, binary(), list(fmt())}.

-spec new(binary()) -> formatter().
new(S) ->
    {formatter, S, []}.

-spec s(formatter(), binary()) -> formatter().
s(Formatter, S) ->
    {formatter,
        erlang:element(2, Formatter),
        lists:append(erlang:element(3, Formatter), [{s, S}])}.

-spec d(formatter(), integer()) -> formatter().
d(Formatter, D) ->
    {formatter,
        erlang:element(2, Formatter),
        lists:append(erlang:element(3, Formatter), [{d, D}])}.

-spec f(formatter(), float()) -> formatter().
f(Formatter, F) ->
    {formatter,
        erlang:element(2, Formatter),
        lists:append(erlang:element(3, Formatter), [{f, F}])}.

-spec process_fmt(binary(), binary(), binary(), list(fmt())) -> {ok, binary()} |
    {error, fmt_error()}.
process_fmt(Placeholder, Value, Str, Values) ->
    case gleam@string:split_once(Str, Placeholder) of
        {ok, {First, Last}} ->
            fmt_iter(
                <<<<First/binary, Value/binary>>/binary, Last/binary>>,
                gleam@list:drop(Values, 1)
            );

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

-spec fmt_iter(binary(), list(fmt())) -> {ok, binary()} | {error, fmt_error()}.
fmt_iter(Str, Values) ->
    case Values of
        [{s, Value} | _] ->
            process_fmt(<<"%s"/utf8>>, Value, Str, Values);

        [{d, Value@1} | _] ->
            process_fmt(
                <<"%d"/utf8>>,
                gleam@int:to_string(Value@1),
                Str,
                Values
            );

        [{f, Value@2} | _] ->
            process_fmt(
                <<"%f"/utf8>>,
                gleam@float:to_string(Value@2),
                Str,
                Values
            );

        [] ->
            {ok, Str}
    end.

-spec try_fmt(binary(), list(fmt())) -> {ok, binary()} | {error, fmt_error()}.
try_fmt(S, V) ->
    _assert_subject = gleam@regex:from_string(<<"(\\%d|\\%f|\\%s)"/utf8>>),
    {ok, Re} = 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 => <<"fmglee"/utf8>>,
                        function => <<"try_fmt"/utf8>>,
                        line => 117})
    end,
    Matches = erlang:length(gleam@regex:scan(Re, S)),
    Values = erlang:length(V),
    case {Matches > Values, Values > Matches} of
        {true, false} ->
            {error, not_enough_values};

        {false, true} ->
            {error, too_many_values};

        {_, _} ->
            fmt_iter(S, V)
    end.

-spec write(binary(), list(fmt()), fun((binary()) -> nil)) -> nil.
write(S, V, Writer) ->
    _assert_subject = try_fmt(S, V),
    {ok, Str} = 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 => <<"fmglee"/utf8>>,
                        function => <<"write"/utf8>>,
                        line => 99})
    end,
    Writer(Str).

-spec print(binary(), list(fmt())) -> nil.
print(S, V) ->
    write(S, V, fun gleam@io:print/1).

-spec println(binary(), list(fmt())) -> nil.
println(S, V) ->
    write(S, V, fun gleam@io:println/1).

-spec writef(formatter(), fun((binary()) -> nil)) -> nil.
writef(Formatter, Writer) ->
    write(erlang:element(2, Formatter), erlang:element(3, Formatter), Writer).

-spec printf(formatter()) -> nil.
printf(Formatter) ->
    writef(Formatter, fun gleam@io:print/1).

-spec printlnf(formatter()) -> nil.
printlnf(Formatter) ->
    writef(Formatter, fun gleam@io:println/1).

-spec fmt(binary(), list(fmt())) -> binary().
fmt(S, V) ->
    _assert_subject = try_fmt(S, V),
    {ok, Str} = 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 => <<"fmglee"/utf8>>,
                        function => <<"fmt"/utf8>>,
                        line => 107})
    end,
    Str.

-spec try_build(formatter()) -> {ok, binary()} | {error, fmt_error()}.
try_build(Formatter) ->
    try_fmt(erlang:element(2, Formatter), erlang:element(3, Formatter)).

-spec build(formatter()) -> binary().
build(Formatter) ->
    _assert_subject = try_build(Formatter),
    {ok, Str} = 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 => <<"fmglee"/utf8>>,
                        function => <<"build"/utf8>>,
                        line => 198})
    end,
    Str.