-module(sqlode@query_analyzer@embed_rewriter).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/sqlode/query_analyzer/embed_rewriter.gleam").
-export([rewrite/2]).

-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(
    " Expand `sqlode.embed(TABLE)` macro calls into concrete qualified column\n"
    " lists inside an already-tokenized query. The rewriter is meant to run\n"
    " after `column_inferencer.infer_result_columns` so that the\n"
    " `EmbeddedResult` entries it receives already have the table's column\n"
    " list resolved against the catalog.\n"
).

-file("src/sqlode/query_analyzer/embed_rewriter.gleam", 30).
-spec collect_embeds(list(sqlode@model:result_item())) -> list(sqlode@model:embedded_column()).
collect_embeds(Result_columns) ->
    gleam@list:filter_map(Result_columns, fun(Item) -> case Item of
                {embedded_result, Embed} ->
                    {ok, Embed};

                {scalar_result, _} ->
                    {error, nil}
            end end).

-file("src/sqlode/query_analyzer/embed_rewriter.gleam", 70).
-spec try_match_embed(list(sqlode@lexer:token())) -> {ok,
        {binary(), list(sqlode@lexer:token())}} |
    {error, nil}.
try_match_embed(Tokens) ->
    case Tokens of
        [{ident, Sqlode_tok},
            dot,
            {ident, Embed_tok},
            l_paren,
            {ident, Table_tok},
            r_paren |
            Rest] ->
            case (string:lowercase(Sqlode_tok) =:= <<"sqlode"/utf8>>) andalso (string:lowercase(
                Embed_tok
            )
            =:= <<"embed"/utf8>>) of
                true ->
                    {ok, {Table_tok, Rest}};

                false ->
                    {error, nil}
            end;

        _ ->
            {error, nil}
    end.

-file("src/sqlode/query_analyzer/embed_rewriter.gleam", 94).
-spec find_embed(list(sqlode@model:embedded_column()), binary()) -> {ok,
        sqlode@model:embedded_column()} |
    {error, nil}.
find_embed(Embeds, Table_token) ->
    Key = string:lowercase(Table_token),
    gleam@list:find(Embeds, fun(E) -> erlang:element(3, E) =:= Key end).

-file("src/sqlode/query_analyzer/embed_rewriter.gleam", 102).
-spec build_column_tokens(sqlode@model:embedded_column()) -> list(sqlode@lexer:token()).
build_column_tokens(Embed) ->
    _pipe = erlang:element(4, Embed),
    _pipe@1 = gleam@list:index_map(
        _pipe,
        fun(Col, Idx) ->
            Prefix = case Idx of
                0 ->
                    [];

                _ ->
                    [comma]
            end,
            lists:append(
                Prefix,
                [{ident, erlang:element(3, Embed)},
                    dot,
                    {ident, erlang:element(2, Col)}]
            )
        end
    ),
    lists:append(_pipe@1).

-file("src/sqlode/query_analyzer/embed_rewriter.gleam", 118).
-spec prepend_reversed(list(NSQ), list(NSQ)) -> list(NSQ).
prepend_reversed(Items, Acc) ->
    case Items of
        [] ->
            Acc;

        [X | Rest] ->
            prepend_reversed(Rest, [X | Acc])
    end.

-file("src/sqlode/query_analyzer/embed_rewriter.gleam", 59).
-spec advance_one(
    list(sqlode@lexer:token()),
    list(sqlode@model:embedded_column()),
    list(sqlode@lexer:token())
) -> list(sqlode@lexer:token()).
advance_one(Tokens, Embeds, Acc) ->
    case Tokens of
        [] ->
            lists:reverse(Acc);

        [T | Rest] ->
            do_rewrite(Rest, Embeds, [T | Acc])
    end.

-file("src/sqlode/query_analyzer/embed_rewriter.gleam", 41).
-spec do_rewrite(
    list(sqlode@lexer:token()),
    list(sqlode@model:embedded_column()),
    list(sqlode@lexer:token())
) -> list(sqlode@lexer:token()).
do_rewrite(Tokens, Embeds, Acc) ->
    case try_match_embed(Tokens) of
        {ok, {Table_token, Rest}} ->
            case find_embed(Embeds, Table_token) of
                {ok, Embed} ->
                    Replacement = build_column_tokens(Embed),
                    do_rewrite(Rest, Embeds, prepend_reversed(Replacement, Acc));

                {error, nil} ->
                    advance_one(Tokens, Embeds, Acc)
            end;

        {error, nil} ->
            advance_one(Tokens, Embeds, Acc)
    end.

-file("src/sqlode/query_analyzer/embed_rewriter.gleam", 19).
?DOC(
    " Rewrite token list, replacing every `sqlode.embed(TABLE)` occurrence with\n"
    " a comma-separated list of qualified columns derived from the matching\n"
    " `EmbeddedResult` in `result_columns`.\n"
    "\n"
    " If `result_columns` contains no `EmbeddedResult`, tokens are returned\n"
    " unchanged — callers can use this to short-circuit re-rendering when\n"
    " there is nothing to do.\n"
).
-spec rewrite(list(sqlode@lexer:token()), list(sqlode@model:result_item())) -> list(sqlode@lexer:token()).
rewrite(Tokens, Result_columns) ->
    Embeds = collect_embeds(Result_columns),
    case Embeds of
        [] ->
            Tokens;

        _ ->
            do_rewrite(Tokens, Embeds, [])
    end.