-module(ranged_int@interface).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([overflowable_limits/2, max_limit/1, min_limit/1, from_bigint/2, compare/3, math_op/4, math_op_unary/3, fallible_op/4, eject/2, overflow/2]).
-export_type([overflowable/0, non_overflowable/0, limits/1, overflowable_limits/0, interface/2]).

-type overflowable() :: overflowable.

-type non_overflowable() :: non_overflowable.

-opaque limits(FQF) :: {limits,
        ranged_int@internal@limit:limit(),
        ranged_int@internal@limit:limit()} |
    {gleam_phantom, FQF}.

-type overflowable_limits() :: {overflowable_limits,
        bigi:big_int(),
        bigi:big_int()}.

-type interface(FQG, FQH) :: {interface,
        fun((FQG) -> bigi:big_int()),
        fun((bigi:big_int()) -> FQG),
        fun(() -> limits(FQH))}.

-spec overflowable_limits(bigi:big_int(), bigi:big_int()) -> limits(overflowable()).
overflowable_limits(Min, Max) ->
    {limits, {bounded, Min}, {bounded, Max}}.

-spec max_limit(bigi:big_int()) -> limits(non_overflowable()).
max_limit(Max) ->
    {limits, unbounded, {bounded, Max}}.

-spec min_limit(bigi:big_int()) -> limits(non_overflowable()).
min_limit(Min) ->
    {limits, {bounded, Min}, unbounded}.

-spec from_bigint(bigi:big_int(), interface(FQO, any())) -> {ok, FQO} |
    {error, ranged_int@utils:overflow()}.
from_bigint(Value, Interface) ->
    Limits = (erlang:element(4, Interface))(),
    case ranged_int@internal@limit:check_limits(
        Value,
        erlang:element(2, Limits),
        erlang:element(3, Limits)
    ) of
        no_overflow ->
            {ok, (erlang:element(3, Interface))(Value)};

        {overflow, Amount} ->
            {error, {would_overflow, Amount}};

        {underflow, Amount@1} ->
            {error, {would_underflow, Amount@1}}
    end.

-spec compare(FQT, FQT, interface(FQT, any())) -> gleam@order:order().
compare(Int1, Int2, Interface) ->
    bigi_ffi:compare(
        (erlang:element(2, Interface))(Int1),
        (erlang:element(2, Interface))(Int2)
    ).

-spec math_op(
    FQX,
    bigi:big_int(),
    interface(FQX, any()),
    fun((bigi:big_int(), bigi:big_int()) -> bigi:big_int())
) -> {ok, FQX} | {error, ranged_int@utils:overflow()}.
math_op(Int1, Int2, Interface, Op) ->
    Limits = (erlang:element(4, Interface))(),
    Int1@1 = (erlang:element(2, Interface))(Int1),
    Result = Op(Int1@1, Int2),
    case ranged_int@internal@limit:check_limits(
        Result,
        erlang:element(2, Limits),
        erlang:element(3, Limits)
    ) of
        no_overflow ->
            {ok, (erlang:element(3, Interface))(Result)};

        {overflow, Amount} ->
            {error, {would_overflow, Amount}};

        {underflow, Amount@1} ->
            {error, {would_underflow, Amount@1}}
    end.

-spec math_op_unary(
    FRC,
    interface(FRC, any()),
    fun((bigi:big_int()) -> bigi:big_int())
) -> {ok, FRC} | {error, ranged_int@utils:overflow()}.
math_op_unary(Int, Interface, Op) ->
    Limits = (erlang:element(4, Interface))(),
    Int@1 = (erlang:element(2, Interface))(Int),
    Result = Op(Int@1),
    case ranged_int@internal@limit:check_limits(
        Result,
        erlang:element(2, Limits),
        erlang:element(3, Limits)
    ) of
        no_overflow ->
            {ok, (erlang:element(3, Interface))(Result)};

        {overflow, Amount} ->
            {error, {would_overflow, Amount}};

        {underflow, Amount@1} ->
            {error, {would_underflow, Amount@1}}
    end.

-spec fallible_op(
    FRH,
    bigi:big_int(),
    interface(FRH, any()),
    fun((bigi:big_int(), bigi:big_int()) -> {ok, bigi:big_int()} | {error, FRL})
) -> {ok, {ok, FRH} | {error, ranged_int@utils:overflow()}} | {error, FRL}.
fallible_op(Int1, Int2, Interface, Op) ->
    Limits = (erlang:element(4, Interface))(),
    Int1@1 = (erlang:element(2, Interface))(Int1),
    gleam@result:'try'(
        Op(Int1@1, Int2),
        fun(Result) ->
            {ok,
                case ranged_int@internal@limit:check_limits(
                    Result,
                    erlang:element(2, Limits),
                    erlang:element(3, Limits)
                ) of
                    no_overflow ->
                        {ok, (erlang:element(3, Interface))(Result)};

                    {overflow, Amount} ->
                        {error, {would_overflow, Amount}};

                    {underflow, Amount@1} ->
                        {error, {would_underflow, Amount@1}}
                end}
        end
    ).

-spec eject(
    {ok, FRW} | {error, ranged_int@utils:overflow()},
    interface(FRW, any())
) -> bigi:big_int().
eject(Value, Interface) ->
    case Value of
        {ok, New_value} ->
            (erlang:element(2, Interface))(New_value);

        {error, Overflow} ->
            case {Overflow, (erlang:element(4, Interface))()} of
                {{would_overflow, Amount}, {limits, _, {bounded, Max}}} ->
                    bigi_ffi:add(Max, Amount);

                {{would_underflow, Amount@1}, {limits, {bounded, Min}, _}} ->
                    bigi_ffi:subtract(Min, Amount@1);

                {_, _} ->
                    erlang:error(#{gleam_error => panic,
                            message => <<"Overflowed but there was no corresponding limit (o_O)"/utf8>>,
                            module => <<"ranged_int/interface"/utf8>>,
                            function => <<"eject"/utf8>>,
                            line => 185})
            end
    end.

-spec destructure_limits(limits(overflowable())) -> overflowable_limits().
destructure_limits(Limits) ->
    _assert_subject = erlang:element(2, Limits),
    {bounded, Min} = case _assert_subject of
        {bounded, _} -> _assert_subject;
        _assert_fail ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"ranged_int/interface"/utf8>>,
                        function => <<"destructure_limits"/utf8>>,
                        line => 193})
    end,
    _assert_subject@1 = erlang:element(3, Limits),
    {bounded, Max} = case _assert_subject@1 of
        {bounded, _} -> _assert_subject@1;
        _assert_fail@1 ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail@1,
                        module => <<"ranged_int/interface"/utf8>>,
                        function => <<"destructure_limits"/utf8>>,
                        line => 194})
    end,
    {overflowable_limits, Min, Max}.

-spec overflow(
    {ok, FRR} | {error, ranged_int@utils:overflow()},
    interface(FRR, overflowable())
) -> FRR.
overflow(Value, Interface) ->
    case Value of
        {ok, New_value} ->
            New_value;

        {error, Overflow} ->
            {overflowable_limits, Min, Max} = destructure_limits(
                (erlang:element(4, Interface))()
            ),
            _pipe = ranged_int@utils:overflow(Overflow, Min, Max),
            (erlang:element(3, Interface))(_pipe)
    end.