%% json_bridge.pl — JSON ↔ Prolog term conversion for Talmudic Engine.
%%
%% Construction §3.3: Bidirectional conversion between the JSON schema
%% defined in the spec and internal Prolog terms used by api.pl.
%%
%% Inbound: JSON dict → Prolog request term
%% Outbound: Prolog response term → JSON dict

:- module(json_bridge, [
    json_to_request/2,
    response_to_json/2,
    parse_root_name/2
]).

:- use_module(library(http/json)).  % NOT library(json) — see note below.
%
%  library(http/json) is the canonical module path and resolves on
%  SWI-Prolog 9.x AND 10.x. The bare alias library(json) resolves only
%  on 10.x, which is what the dev workstation runs; the image is built
%  on swipl 9.2.2 as pinned by specs/shorashim_vayakhel.md §1.1, where
%  it does NOT resolve. The consequence was invisible to the test
%  suite (212 tests green on the host) and fatal in the container:
%    ERROR: source_sink `library(json)' does not exist
%    ERROR: Unknown procedure: start_socket_server/0
%  exit 2, before the socket was ever opened.
:- use_module(library(lists)).

%% ============================================================
%% INBOUND: JSON → Prolog request
%% ============================================================

%% Convert a JSON dict (as parsed by SWI-Prolog's json library) to a
%% Prolog request term compatible with api:process_request/2.
%%
%% JSON format (Construction §3.3):
%%   { "action": "interpret", "case": { "ref": "case-uuid",
%%     "facts": [...], "question": "...", "context_roots": [...] } }
%%
%% Prolog format:
%%   request(interpret, CaseRef, Domain, Roots, Question)

json_to_request(Dict, request(Action, CaseRef, Domain, Roots, Question)) :-
    get_dict(action, Dict, ActionStr),
    atom_string(Action, ActionStr),
    get_dict(case, Dict, CaseDict),
    get_dict(ref, CaseDict, RefStr),
    atom_string(CaseRef, RefStr),
    %% Extract question
    (   get_dict(question, CaseDict, QuestionStr)
    ->  atom_string(Question, QuestionStr)
    ;   Question = none
    ),
    %% Extract context_roots and derive domain
    (   get_dict(context_roots, CaseDict, RootNames)
    ->  maplist(parse_root_name, RootNames, Roots)
    ;   Roots = []
    ),
    %% Derive domain from roots (first root's known domain, or 'general')
    (   Roots = [FirstRoot|_],
        root_to_domain(FirstRoot, D)
    ->  Domain = D
    ;   Domain = general
    ).

%% Handle halt_check action (different format — no case, just action)
json_to_request(Dict, request(halt_check, Action)) :-
    get_dict(action, Dict, "halt_check"),
    get_dict(check, Dict, CheckDict),
    get_dict(type, CheckDict, TypeStr),
    atom_string(Type, TypeStr),
    (   get_dict(target, CheckDict, TargetStr)
    ->  atom_string(Target, TargetStr)
    ;   Target = unknown
    ),
    (   get_dict(source, CheckDict, SourceStr)
    ->  atom_string(Source, SourceStr)
    ;   Source = unknown
    ),
    Action = action(Type, source(Source), target(Target)).


%% ============================================================
%% OUTBOUND: Prolog response → JSON
%% ============================================================

%% Convert a Prolog response from api.pl to a JSON-serializable dict.
%%
%% Prolog format: response(ok, interpreted, result(...))
%% JSON format (Construction §3.3):
%%   { "status": "resolved", "interpretation": { ... } }

%% Interpreted response
response_to_json(response(ok, interpreted, result(ref(Ref), mitzvot(Mitzvot),
                                                   verses(Verses), reading(Reading),
                                                   confidence(Conf))),
                 Dict) :-
    maplist(term_to_string, Mitzvot, MitzvotStrs),
    maplist(term_to_string, Verses, VerseStrs),
    term_to_string(Reading, ReadingStr),
    atom_string(Conf, ConfStr),
    atom_string(Ref, RefStr),
    Dict = json{status: "resolved",
                interpretation: json{text: ReadingStr,
                                     prolog_form: RefStr,
                                     grounding: MitzvotStrs,
                                     verses: VerseStrs,
                                     confidence: ConfStr},
                challenge: null}.

%% Challenged response
response_to_json(response(ok, resolved_challenged,
                          result(interpretation(Interp), challenge(Kushya))),
                 Dict) :-
    term_to_string(Interp, InterpStr),
    term_to_string(Kushya, KushyaStr),
    Dict = json{status: "challenged",
                interpretation: json{text: InterpStr,
                                     prolog_form: InterpStr,
                                     grounding: [],
                                     confidence: "medium"},
                challenge: json{kushya: KushyaStr,
                                contradicting: "",
                                strength: "moderate"}}.

%% Teiku response
response_to_json(response(ok, teiku, result(record(Record))), Dict) :-
    term_to_string(Record, RecordStr),
    Dict = json{status: "teiku",
                interpretation: json{text: RecordStr,
                                     prolog_form: RecordStr,
                                     grounding: [],
                                     confidence: "low"},
                challenge: null}.

%% No interpretation
response_to_json(response(error, no_interpretation, CaseRef), Dict) :-
    atom_string(CaseRef, RefStr),
    Dict = json{status: "teiku",
                interpretation: json{text: "No interpretation found",
                                     prolog_form: RefStr,
                                     grounding: [],
                                     confidence: "low"},
                challenge: null}.

%% No resolution
response_to_json(response(error, no_resolution, CaseRef), Dict) :-
    atom_string(CaseRef, RefStr),
    Dict = json{status: "teiku",
                interpretation: json{text: "No resolution found",
                                     prolog_form: RefStr,
                                     grounding: [],
                                     confidence: "low"},
                challenge: null}.

%% Halt response
response_to_json(response(halt, violations(Halts), action(Action)), Dict) :-
    maplist(term_to_string, Halts, HaltStrs),
    term_to_string(Action, ActionStr),
    Dict = json{status: "halt",
                violations: HaltStrs,
                action: ActionStr}.

%% No halt
response_to_json(response(ok, no_halt, action(Action)), Dict) :-
    term_to_string(Action, ActionStr),
    Dict = json{status: "ok",
                violations: [],
                action: ActionStr}.

%% Catch-all for unexpected responses
response_to_json(Response, Dict) :-
    term_to_string(Response, Str),
    Dict = json{status: "error",
                error: json{code: "UNEXPECTED_RESPONSE",
                            message: Str}}.


%% ============================================================
%% HELPERS
%% ============================================================

%% Parse a root name like "bet-resh-aleph" into an atom bet_resh_aleph
parse_root_name(Name, Atom) :-
    (   string(Name) -> S = Name
    ;   atom_string(Name, S)
    ),
    split_string(S, "-", "", Parts),
    atomic_list_concat(Parts, '_', Atom).

%% Convert any Prolog term to a string
term_to_string(Term, Str) :-
    term_string(Term, Str).

%% Map known roots to domains (basic mapping; will be extended)
root_to_domain(bet_resh_aleph, creation).
root_to_domain(yod_tsade_resh, creation).
root_to_domain(aleph_lamed_he, holiness).
root_to_domain(qof_dalet_shin, holiness).
root_to_domain(shin_pe_tet, judgment).
root_to_domain(dalet_yod_nun, judgment).
root_to_domain(chet_samekh_dalet, mercy).
root_to_domain(resh_chet_mem, mercy).
root_to_domain(aleph_vav_resh, light).
root_to_domain(chet_shin_kaf, darkness).