% :- module(lsp_metta_completion, [completions_at/3]).
% /** <module> LSP Completion
%
% This module implements code completion, based on defined predicates in
% the file & imports.
%
% Uses =lsp_metta_changes= in order to see the state of the buffer being edited.
%
% @see lsp_metta_changes:doc_text_fallback/2
%
% @author James Cash
% */
%
% :- use_module(library(apply), [maplist/3]).
% :- use_module(library(lists), [numlist/3]).
% :- use_module(library(prolog_xref), [xref_defined/3, xref_source/2]).
% :- use_module(library(yall)).
% :- use_module(lsp_metta_utils, [linechar_offset/3]).
% :- use_module(lsp_metta_changes, [doc_text_fallback/2]).
%
% part_of_prefix(Code) :- code_type(Code, prolog_var_start).
% part_of_prefix(Code) :- code_type(Code, prolog_atom_start).
% part_of_prefix(Code) :- code_type(Code, prolog_identifier_continue).
%
% get_prefix_codes(Stream, Offset, Codes) :-
%     get_prefix_codes(Stream, Offset, [], Codes).
%
% get_prefix_codes(Stream, Offset0, Codes0, Codes) :-
%     peek_code(Stream, Code),
%     part_of_prefix(Code), !,
%     succ(Offset1, Offset0),
%     seek(Stream, Offset1, bof, Offset),
%     get_prefix_codes(Stream, Offset, [Code|Codes0], Codes).
% get_prefix_codes(_, _, Codes, Codes).
%
% prefix_at(File, Position, Prefix) :-
%     doc_text_fallback(File, DocCodes),
%     setup_call_cleanup(
%         open_string(DocCodes, Stream),
%         ( linechar_offset(Stream, Position, _),
%           seek(Stream, -1, current, Offset),
%           get_prefix_codes(Stream, Offset, PrefixCodes),
%           string_codes(Prefix, PrefixCodes) ),
%         close(Stream)
%     ).
%
% completions_at(File, Position, Completions) :-
%     prefix_at(File, Position, Prefix),
%     xref_source(File, [silent(true)]),
%     findall(
%         Result,
%         ( xref_defined(File, Goal, _),
%           functor(Goal, Name, Arity),
%           atom_concat(Prefix, _, Name),
%           args_str(Arity, Args),
%           format(string(Func), "~w(~w)$0", [Name, Args]),
%           format(string(Label), "~w/~w", [Name, Arity]),
%           Result = _{label: Label,
%                      insertText: Func,
%                      insertTextFormat: 2}),
%         Completions
%     ).
%
% args_str(Arity, Str) :-
%     numlist(1, Arity, Args),
%     maplist([A, S]>>format(string(S), "${~w:_}", [A]),
%            Args, ArgStrs),
%     atomic_list_concat(ArgStrs, ', ', Str).