-module(gleamy@priority_queue).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([new/1, pop/1, peek/1, push/2, is_empty/1, count/1, reorder/2, from_list/2, to_list/1]).

-spec new(fun((GVM, GVM) -> gleam@order:order())) -> gleamy@pairing_heap:heap(GVM).
new(Compare) ->
    gleamy@pairing_heap:new(Compare).

-spec pop(gleamy@pairing_heap:heap(GVO)) -> {ok,
        {GVO, gleamy@pairing_heap:heap(GVO)}} |
    {error, nil}.
pop(Queue) ->
    gleamy@pairing_heap:delete_min(Queue).

-spec peek(gleamy@pairing_heap:heap(GVT)) -> {ok, GVT} | {error, nil}.
peek(Queue) ->
    gleamy@pairing_heap:find_min(Queue).

-spec push(gleamy@pairing_heap:heap(GVX), GVX) -> gleamy@pairing_heap:heap(GVX).
push(Queue, Item) ->
    gleamy@pairing_heap:insert(Queue, Item).

-spec is_empty(gleamy@pairing_heap:heap(any())) -> boolean().
is_empty(Queue) ->
    case gleamy@pairing_heap:find_min(Queue) of
        {ok, _} ->
            false;

        {error, _} ->
            true
    end.

-spec count(gleamy@pairing_heap:heap(any())) -> integer().
count(Queue) ->
    case gleamy@pairing_heap:delete_min(Queue) of
        {ok, {_, Q}} ->
            count(Q) + 1;

        {error, _} ->
            0
    end.

-spec reorder(
    gleamy@pairing_heap:heap(GWE),
    fun((GWE, GWE) -> gleam@order:order())
) -> gleamy@pairing_heap:heap(GWE).
reorder(Queue, Compare) ->
    case gleamy@pairing_heap:delete_min(Queue) of
        {ok, {X, Q}} ->
            gleamy@pairing_heap:insert(reorder(Q, Compare), X);

        {error, _} ->
            gleamy@pairing_heap:new(Compare)
    end.

-spec from_list(list(GWH), fun((GWH, GWH) -> gleam@order:order())) -> gleamy@pairing_heap:heap(GWH).
from_list(List, Compare) ->
    gleam@list:fold(List, new(Compare), fun gleamy@pairing_heap:insert/2).

-spec to_list(gleamy@pairing_heap:heap(GWK)) -> list(GWK).
to_list(Queue) ->
    case gleamy@pairing_heap:delete_min(Queue) of
        {ok, {X, Q}} ->
            [X | to_list(Q)];

        {error, _} ->
            []
    end.