-module(etui@widgets@list).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/etui/widgets/list.gleam").
-export([list_new/1, list_new_styled/1, with_colors/3, with_highlight_style/2, with_style/2, with_blink/2, state_new/0, select/2, select_next/2, select_prev/1, clamp_state/2, render/3, render_stateful/4, render_animated/5, effective_offset/2]).
-export_type([list_widget/0, list_state/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.

-type list_widget() :: {list_widget,
        list(etui@span:line()),
        etui@style:color(),
        etui@style:color(),
        etui@style:style(),
        integer()}.

-type list_state() :: {list_state, integer(), integer()}.

-file("src/etui/widgets/list.gleam", 34).
?DOC(" New list from plain strings. Default colors, reverse-video selection.\n").
-spec list_new(list(binary())) -> list_widget().
list_new(Items) ->
    {list_widget,
        gleam@list:map(Items, fun etui@span:line_plain/1),
        default,
        default,
        {style, default, default, etui@style:reverse()},
        0}.

-file("src/etui/widgets/list.gleam", 56).
?DOC(
    " New list from styled `span.Line` items.\n"
    "\n"
    " ```gleam\n"
    " list.list_new_styled([\n"
    "   span.line_new([span.span_styled(\"ERROR\", style.bold_style()), span.span_plain(\" file\")]),\n"
    "   span.line_plain(\"normal item\"),\n"
    " ])\n"
    " ```\n"
).
-spec list_new_styled(list(etui@span:line())) -> list_widget().
list_new_styled(Items) ->
    {list_widget,
        Items,
        default,
        default,
        {style, default, default, etui@style:reverse()},
        0}.

-file("src/etui/widgets/list.gleam", 70).
-spec with_colors(list_widget(), etui@style:color(), etui@style:color()) -> list_widget().
with_colors(L, Fg, Bg) ->
    {list_widget,
        erlang:element(2, L),
        Fg,
        Bg,
        erlang:element(5, L),
        erlang:element(6, L)}.

-file("src/etui/widgets/list.gleam", 78).
-spec with_highlight_style(list_widget(), etui@style:style()) -> list_widget().
with_highlight_style(L, S) ->
    {list_widget,
        erlang:element(2, L),
        erlang:element(3, L),
        erlang:element(4, L),
        S,
        erlang:element(6, L)}.

-file("src/etui/widgets/list.gleam", 82).
-spec with_style(list_widget(), etui@style:style()) -> list_widget().
with_style(L, S) ->
    {list_widget,
        erlang:element(2, L),
        erlang:element(2, S),
        erlang:element(3, S),
        erlang:element(5, L),
        erlang:element(6, L)}.

-file("src/etui/widgets/list.gleam", 87).
?DOC(" Blink period in frames. 0 = steady (no blink). Use with `render_animated`.\n").
-spec with_blink(list_widget(), integer()) -> list_widget().
with_blink(L, Period) ->
    {list_widget,
        erlang:element(2, L),
        erlang:element(3, L),
        erlang:element(4, L),
        erlang:element(5, L),
        Period}.

-file("src/etui/widgets/list.gleam", 94).
-spec state_new() -> list_state().
state_new() ->
    {list_state, 0, 0}.

-file("src/etui/widgets/list.gleam", 98).
-spec select(list_state(), integer()) -> list_state().
select(State, Idx) ->
    {list_state, gleam@int:max(0, Idx), erlang:element(3, State)}.

-file("src/etui/widgets/list.gleam", 102).
-spec select_next(list_state(), integer()) -> list_state().
select_next(State, Item_count) ->
    Max_idx = gleam@int:max(0, Item_count - 1),
    {list_state,
        gleam@int:min(Max_idx, erlang:element(2, State) + 1),
        erlang:element(3, State)}.

-file("src/etui/widgets/list.gleam", 107).
-spec select_prev(list_state()) -> list_state().
select_prev(State) ->
    {list_state,
        gleam@int:max(0, erlang:element(2, State) - 1),
        erlang:element(3, State)}.

-file("src/etui/widgets/list.gleam", 113).
?DOC(
    " Clamp `selected` to `[0, item_count - 1]`.\n"
    " Call after replacing the item list to avoid a stale selection index.\n"
).
-spec clamp_state(list_state(), integer()) -> list_state().
clamp_state(State, Item_count) ->
    Max = gleam@int:max(0, Item_count - 1),
    {list_state,
        gleam@int:min(erlang:element(2, State), Max),
        erlang:element(3, State)}.

-file("src/etui/widgets/list.gleam", 239).
-spec apply_highlight_to_line(etui@span:line(), etui@style:style()) -> etui@span:line().
apply_highlight_to_line(Line, Hl) ->
    etui@span:line_new(
        gleam@list:map(
            erlang:element(2, Line),
            fun(Sp) ->
                New_fg = case erlang:element(3, Sp) of
                    default ->
                        erlang:element(2, Hl);

                    _ ->
                        erlang:element(3, Sp)
                end,
                New_bg = case erlang:element(4, Sp) of
                    default ->
                        erlang:element(3, Hl);

                    _ ->
                        erlang:element(4, Sp)
                end,
                New_mod = case etui@style:modifier_equal(
                    erlang:element(5, Sp),
                    etui@style:none()
                ) of
                    true ->
                        erlang:element(4, Hl);

                    false ->
                        erlang:element(5, Sp)
                end,
                {span,
                    erlang:element(2, Sp),
                    New_fg,
                    New_bg,
                    New_mod,
                    erlang:element(6, Sp)}
            end
        )
    ).

-file("src/etui/widgets/list.gleam", 284).
-spec get_item_at(list(etui@span:line()), integer()) -> {ok, etui@span:line()} |
    {error, nil}.
get_item_at(Items, Idx) ->
    case Idx of
        I when I < 0 ->
            {error, nil};

        0 ->
            case Items of
                [H | _] ->
                    {ok, H};

                [] ->
                    {error, nil}
            end;

        _ ->
            get_item_at(gleam@list:drop(Items, 1), Idx - 1)
    end.

-file("src/etui/widgets/list.gleam", 168).
-spec do_render(
    etui@buffer:buffer(),
    etui@geometry:rect(),
    list_widget(),
    integer(),
    integer(),
    integer()
) -> etui@buffer:buffer().
do_render(Buf, Area, L, Selected, Offset, Y_offset) ->
    case Y_offset >= erlang:element(3, erlang:element(3, Area)) of
        true ->
            Buf;

        false ->
            Item_idx = Offset + Y_offset,
            Y = erlang:element(3, erlang:element(2, Area)) + Y_offset,
            Is_selected = Item_idx =:= Selected,
            {Row_fg, Row_bg, Row_mod} = case Is_selected of
                true ->
                    {erlang:element(2, erlang:element(5, L)),
                        erlang:element(3, erlang:element(5, L)),
                        erlang:element(4, erlang:element(5, L))};

                false ->
                    {erlang:element(3, L),
                        erlang:element(4, L),
                        etui@style:none()}
            end,
            Bg_row = etui@text:pad_right(
                <<""/utf8>>,
                erlang:element(2, erlang:element(3, Area))
            ),
            Buf1 = etui@buffer:set_string(
                Buf,
                {position, erlang:element(2, erlang:element(2, Area)), Y},
                Bg_row,
                Row_fg,
                Row_bg,
                Row_mod
            ),
            Buf2 = case get_item_at(erlang:element(2, L), Item_idx) of
                {error, _} ->
                    Buf1;

                {ok, Line} ->
                    Prefix = case Is_selected of
                        true ->
                            <<"▶ "/utf8>>;

                        false ->
                            <<"  "/utf8>>
                    end,
                    Prefix_w = etui@text:cell_width(Prefix),
                    Buf3 = etui@buffer:set_string(
                        Buf1,
                        {position,
                            erlang:element(2, erlang:element(2, Area)),
                            Y},
                        Prefix,
                        Row_fg,
                        Row_bg,
                        Row_mod
                    ),
                    Effective_line = case Is_selected of
                        false ->
                            Line;

                        true ->
                            apply_highlight_to_line(Line, erlang:element(5, L))
                    end,
                    etui@span:render_line(
                        Buf3,
                        {position,
                            erlang:element(2, erlang:element(2, Area)) + Prefix_w,
                            Y},
                        Effective_line,
                        erlang:element(2, erlang:element(3, Area)) - Prefix_w
                    )
            end,
            do_render(Buf2, Area, L, Selected, Offset, Y_offset + 1)
    end.

-file("src/etui/widgets/list.gleam", 121).
-spec render(etui@buffer:buffer(), etui@geometry:rect(), list_widget()) -> etui@buffer:buffer().
render(Buf, Area, L) ->
    case erlang:element(3, erlang:element(3, Area)) =< 0 of
        true ->
            Buf;

        false ->
            do_render(Buf, Area, L, -1, 0, 0)
    end.

-file("src/etui/widgets/list.gleam", 266).
-spec scroll_offset(integer(), integer(), integer()) -> integer().
scroll_offset(Selected, Offset, Height) ->
    case Selected < Offset of
        true ->
            Selected;

        false ->
            case Height =< 0 of
                true ->
                    Offset;

                false ->
                    case Selected >= (Offset + Height) of
                        true ->
                            (Selected - Height) + 1;

                        false ->
                            Offset
                    end
            end
    end.

-file("src/etui/widgets/list.gleam", 132).
-spec render_stateful(
    etui@buffer:buffer(),
    etui@geometry:rect(),
    list_widget(),
    list_state()
) -> etui@buffer:buffer().
render_stateful(Buf, Area, L, State) ->
    case erlang:element(3, erlang:element(3, Area)) =< 0 of
        true ->
            Buf;

        false ->
            Offset = scroll_offset(
                erlang:element(2, State),
                erlang:element(3, State),
                erlang:element(3, erlang:element(3, Area))
            ),
            do_render(Buf, Area, L, erlang:element(2, State), Offset, 0)
    end.

-file("src/etui/widgets/list.gleam", 147).
-spec render_animated(
    etui@buffer:buffer(),
    etui@geometry:rect(),
    list_widget(),
    list_state(),
    integer()
) -> etui@buffer:buffer().
render_animated(Buf, Area, L, State, Frame) ->
    case erlang:element(3, erlang:element(3, Area)) =< 0 of
        true ->
            Buf;

        false ->
            Offset = scroll_offset(
                erlang:element(2, State),
                erlang:element(3, State),
                erlang:element(3, erlang:element(3, Area))
            ),
            Show = etui@anim:blink(Frame, erlang:element(6, L)),
            Sel = case Show of
                true ->
                    erlang:element(2, State);

                false ->
                    -1
            end,
            do_render(Buf, Area, L, Sel, Offset, 0)
    end.

-file("src/etui/widgets/list.gleam", 262).
-spec effective_offset(list_state(), integer()) -> integer().
effective_offset(State, Height) ->
    scroll_offset(erlang:element(2, State), erlang:element(3, State), Height).