url_join

-module(url_join).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/url_join.gleam").
-export([join/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(
    " Join URL path segments and normalize the result.\n"
    "\n"
    " A simple and clean library for combining URL segments into a properly\n"
    " formatted URL. Handles protocols, slashes, query parameters, and hash\n"
    " fragments automatically.\n"
    "\n"
    " ## Example\n"
    "\n"
    " ```gleam\n"
    " import url_join\n"
    "\n"
    " let url = url_join.join([\n"
    "   \"https://example.com\",\n"
    "   \"api\",\n"
    "   \"v1\",\n"
    "   \"users\",\n"
    "   \"?page=1\",\n"
    " ])\n"
    " // -> \"https://example.com/api/v1/users?page=1\"\n"
    " ```\n"
).

-file("src/url_join.gleam", 96).
-spec only_slashes_or_empty(binary()) -> boolean().
only_slashes_or_empty(S) ->
    gleam@string:replace(S, <<"/"/utf8>>, <<""/utf8>>) =:= <<""/utf8>>.

-file("src/url_join.gleam", 88).
-spec is_plain_protocol(binary()) -> boolean().
is_plain_protocol(S) ->
    case gleam@string:split_once(S, <<":"/utf8>>) of
        {ok, {Before, After}} ->
            not gleam_stdlib:contains_string(Before, <<"/"/utf8>>) andalso only_slashes_or_empty(
                After
            );

        {error, _} ->
            false
    end.

-file("src/url_join.gleam", 129).
-spec drop_leading_slashes(binary()) -> binary().
drop_leading_slashes(S) ->
    case gleam_stdlib:string_starts_with(S, <<"/"/utf8>>) of
        true ->
            drop_leading_slashes(gleam@string:drop_start(S, 1));

        false ->
            S
    end.

-file("src/url_join.gleam", 104).
-spec normalize_protocol(binary()) -> binary().
normalize_protocol(S) ->
    Is_ipv6 = gleam_stdlib:string_starts_with(S, <<"["/utf8>>) andalso gleam_stdlib:contains_string(
        S,
        <<"]"/utf8>>
    ),
    Has_full_protocol = gleam_stdlib:contains_string(S, <<"://"/utf8>>),
    case S of
        <<"file:///"/utf8, _/binary>> ->
            S;

        <<"file:"/utf8, Rest/binary>> ->
            <<"file:///"/utf8, (drop_leading_slashes(Rest))/binary>>;

        _ ->
            case Is_ipv6 orelse Has_full_protocol of
                true ->
                    S;

                false ->
                    case gleam@string:split_once(S, <<":"/utf8>>) of
                        {ok, {Protocol, Rest@1}} ->
                            <<<<Protocol/binary, "://"/utf8>>/binary,
                                (drop_leading_slashes(Rest@1))/binary>>;

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

-file("src/url_join.gleam", 76).
-spec merge_leading_parts(binary(), list(binary())) -> list(binary()).
merge_leading_parts(First, Rest) ->
    case Rest of
        [] ->
            [normalize_protocol(First)];

        [Next | Tail] ->
            case (First =:= <<"/"/utf8>>) orelse is_plain_protocol(First) of
                true ->
                    merge_leading_parts(<<First/binary, Next/binary>>, Tail);

                false ->
                    [normalize_protocol(First) | Rest]
            end
    end.

-file("src/url_join.gleam", 136).
-spec drop_trailing_slashes(binary()) -> binary().
drop_trailing_slashes(S) ->
    case gleam_stdlib:string_ends_with(S, <<"/"/utf8>>) of
        true ->
            drop_trailing_slashes(gleam@string:drop_end(S, 1));

        false ->
            S
    end.

-file("src/url_join.gleam", 143).
-spec collapse_trailing_slashes(binary()) -> binary().
collapse_trailing_slashes(S) ->
    Trimmed = drop_trailing_slashes(S),
    case gleam_stdlib:string_ends_with(S, <<"/"/utf8>>) andalso (Trimmed /= <<""/utf8>>) of
        true ->
            <<Trimmed/binary, "/"/utf8>>;

        false ->
            Trimmed
    end.

-file("src/url_join.gleam", 156).
-spec process_parts(list(binary())) -> list(binary()).
process_parts(Parts) ->
    Len = erlang:length(Parts),
    _pipe = Parts,
    _pipe@1 = gleam@list:index_map(
        _pipe,
        fun(Part, Index) ->
            Is_first = Index =:= 0,
            Is_last = Index =:= (Len - 1),
            No_leading = case Is_first of
                true ->
                    Part;

                false ->
                    drop_leading_slashes(Part)
            end,
            case Is_last of
                true ->
                    collapse_trailing_slashes(No_leading);

                false ->
                    drop_trailing_slashes(No_leading)
            end
        end
    ),
    gleam@list:filter(_pipe@1, fun(P) -> P /= <<""/utf8>> end).

-file("src/url_join.gleam", 183).
-spec join_two_parts(binary(), binary()) -> binary().
join_two_parts(Prev, Part) ->
    case gleam_stdlib:string_ends_with(Prev, <<"?"/utf8>>) orelse gleam_stdlib:string_ends_with(
        Prev,
        <<"#"/utf8>>
    ) of
        true ->
            <<Prev/binary, Part/binary>>;

        false ->
            <<<<Prev/binary, "/"/utf8>>/binary, Part/binary>>
    end.

-file("src/url_join.gleam", 176).
-spec join_parts(list(binary())) -> binary().
join_parts(Parts) ->
    case Parts of
        [] ->
            <<""/utf8>>;

        [First | Rest] ->
            gleam@list:fold(Rest, First, fun join_two_parts/2)
    end.

-file("src/url_join.gleam", 223).
-spec split_query_parts(binary()) -> list(binary()).
split_query_parts(S) ->
    _pipe = S,
    _pipe@1 = gleam@string:replace(_pipe, <<"?"/utf8>>, <<"&"/utf8>>),
    _pipe@2 = gleam@string:split(_pipe@1, <<"&"/utf8>>),
    gleam@list:filter(_pipe@2, fun(X) -> X /= <<""/utf8>> end).

-file("src/url_join.gleam", 215).
-spec build_query(binary()) -> binary().
build_query(S) ->
    case split_query_parts(S) of
        [] ->
            S;

        [Path] ->
            Path;

        [Path@1 | Params] ->
            <<<<Path@1/binary, "?"/utf8>>/binary,
                (gleam@string:join(Params, <<"&"/utf8>>))/binary>>
    end.

-file("src/url_join.gleam", 202).
-spec normalize_query_params(binary()) -> binary().
normalize_query_params(S) ->
    case gleam@string:split_once(S, <<"#"/utf8>>) of
        {ok, {Before_hash, After_hash}} ->
            Query = build_query(Before_hash),
            case After_hash of
                <<""/utf8>> ->
                    Query;

                _ ->
                    <<<<Query/binary, "#"/utf8>>/binary, After_hash/binary>>
            end;

        {error, _} ->
            build_query(S)
    end.

-file("src/url_join.gleam", 194).
-spec normalize_query(binary()) -> binary().
normalize_query(S) ->
    _pipe = S,
    _pipe@1 = gleam@string:replace(_pipe, <<"/?"/utf8>>, <<"?"/utf8>>),
    _pipe@2 = gleam@string:replace(_pipe@1, <<"/#"/utf8>>, <<"#"/utf8>>),
    _pipe@3 = gleam@string:replace(_pipe@2, <<"/&"/utf8>>, <<"&"/utf8>>),
    normalize_query_params(_pipe@3).

-file("src/url_join.gleam", 60).
-spec normalize(list(binary())) -> binary().
normalize(Segments) ->
    case Segments of
        [] ->
            <<""/utf8>>;

        [First | Rest] ->
            _pipe = First,
            _pipe@1 = merge_leading_parts(_pipe, Rest),
            _pipe@2 = process_parts(_pipe@1),
            _pipe@3 = join_parts(_pipe@2),
            normalize_query(_pipe@3)
    end.

-file("src/url_join.gleam", 54).
?DOC(
    " Join URL path segments and normalize the result.\n"
    "\n"
    " This function takes a list of URL segments and combines them into a single,\n"
    " properly normalized URL. It handles protocols, slashes, query strings, and\n"
    " hash fragments intelligently.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " join([\"http://www.google.com\", \"a\", \"/b/cd\", \"?foo=123\"])\n"
    " // -> \"http://www.google.com/a/b/cd?foo=123\"\n"
    "\n"
    " join([\"https://example.com/\", \"/api/\", \"users\"])\n"
    " // -> \"https://example.com/api/users\"\n"
    "\n"
    " join([\"a\", \"b\", \"c\"])\n"
    " // -> \"a/b/c\"\n"
    " ```\n"
    "\n"
    " ## Behaviour\n"
    "\n"
    " - Filters out empty segments\n"
    " - Merges a leading bare protocol (e.g. `\"http:\"`) with the next segment\n"
    " - Merges a leading `\"/\"` with the next segment  \n"
    " - Normalises protocols to `protocol://` (and `file:///` for file)\n"
    " - Trims and collapses slashes between segments\n"
    " - Does not add a slash before `?`, `#`, or `&`\n"
    " - Normalises query string (multiple `?`/`&` become a single `?` then `&`)\n"
).
-spec join(list(binary())) -> binary().
join(Parts) ->
    _pipe = Parts,
    _pipe@1 = gleam@list:filter(_pipe, fun(Part) -> Part /= <<""/utf8>> end),
    normalize(_pipe@1).