-module(prequel@error@validation_error).
-compile([no_auto_import, nowarn_unused_vars]).

-export([to_report/3]).
-export_type([validation_error/0]).

-type validation_error() :: {lower_bound_greater_than_upper_bound,
        gleam@option:option(binary()),
        prequel@span:span(),
        prequel@ast:cardinality()} |
    {duplicate_entity_name,
        gleam@option:option(binary()),
        prequel@ast:entity(),
        prequel@ast:entity()} |
    {duplicate_relationship_name,
        gleam@option:option(binary()),
        prequel@ast:relationship(),
        prequel@ast:relationship()}.

-spec main_span(validation_error()) -> prequel@span:span().
main_span(Error) ->
    case Error of
        {lower_bound_greater_than_upper_bound, _, _, Cardinality} ->
            erlang:element(2, Cardinality);

        {duplicate_entity_name, _, _, Other_entity} ->
            erlang:element(2, Other_entity);

        {duplicate_relationship_name, _, _, Other_relationship} ->
            erlang:element(2, Other_relationship)
    end.

-spec name(validation_error()) -> binary().
name(Error) ->
    case Error of
        {lower_bound_greater_than_upper_bound, _, _, _} ->
            <<"Lower bound greater than upper bound"/utf8>>;

        {duplicate_entity_name, _, _, _} ->
            <<"Duplicate entity name"/utf8>>;

        {duplicate_relationship_name, _, _, _} ->
            <<"Duplicate relationship name"/utf8>>
    end.

-spec code(validation_error()) -> binary().
code(Error) ->
    case Error of
        {lower_bound_greater_than_upper_bound, _, _, _} ->
            <<"VE001"/utf8>>;

        {duplicate_entity_name, _, _, _} ->
            <<"VE002"/utf8>>;

        {duplicate_relationship_name, _, _, _} ->
            <<"VE003"/utf8>>
    end.

-spec message(validation_error()) -> binary().
message(Error) ->
    case Error of
        {lower_bound_greater_than_upper_bound, _, _, _} ->
            <<"The lower bound of a cardinality should always be lower than its upper bound"/utf8>>;

        {duplicate_entity_name, _, _, _} ->
            <<"Two entities cannot have the same name. Here is the first one..."/utf8>>;

        {duplicate_relationship_name, _, _, _} ->
            <<"Two relationships cannot have the same name. Here is the first one..."/utf8>>
    end.

-spec blocks(validation_error()) -> non_empty_list:non_empty_list(prequel@internals@report:report_block()).
blocks(Error) ->
    case Error of
        {lower_bound_greater_than_upper_bound, _, Enclosing_entity, Cardinality} ->
            non_empty_list:new(
                {context_block, Enclosing_entity},
                [{error_block,
                        erlang:element(2, Cardinality),
                        none,
                        message(Error)}]
            );

        {duplicate_entity_name, _, One, Other} ->
            non_empty_list:new(
                {error_block, erlang:element(2, One), none, message(Error)},
                [{error_block,
                        erlang:element(2, Other),
                        none,
                        <<"...and here is the other one"/utf8>>}]
            );

        {duplicate_relationship_name, _, One@1, Other@1} ->
            non_empty_list:new(
                {error_block, erlang:element(2, One@1), none, message(Error)},
                [{error_block,
                        erlang:element(2, Other@1),
                        none,
                        <<"...and here is the other one"/utf8>>}]
            )
    end.

-spec to_report(validation_error(), binary(), binary()) -> prequel@internals@report:report().
to_report(Error, File_name, Source_code) ->
    Main_span = main_span(Error),
    Line = erlang:element(2, Main_span),
    Column = erlang:element(4, Main_span),
    Name = name(Error),
    Code = code(Error),
    Blocks = blocks(Error),
    {report,
        File_name,
        Source_code,
        Name,
        Code,
        Line,
        Column,
        Blocks,
        erlang:element(2, Error)}.