require "fileutils"
require "open3"

Results = Struct.new(:stdout, :stderr, :status)

describe Propane do
  def write_grammar(grammar, options = {})
    options[:name] ||= ""
    File.write("spec/run/testparser#{options[:name]}.propane", grammar)
  end

  def build_parser(options = {})
    options[:name] ||= ""
    command = %W[./propane.sh spec/run/testparser#{options[:name]}.propane spec/run/testparser#{options[:name]}.#{options[:language]} --log spec/run/testparser#{options[:name]}.log]
    if (options[:capture])
      stdout, stderr, status = Open3.capture3(*command)
      Results.new(stdout, stderr, status)
    else
      result = system(*command)
      expect(result).to be_truthy
    end
  end

  def compile(test_files, options = {})
    test_files = Array(test_files)
    options[:parsers] ||= [""]
    parsers = options[:parsers].map do |name|
      "spec/run/testparser#{name}.#{options[:language]}"
    end
    case options[:language]
    when "c"
      result = system(*%w[gcc -Wall -o spec/run/testparser -Ispec -Ispec/run], *parsers, *test_files, "spec/testutils.c", "-lm")
    when "d"
      result = system(*%w[ldc2 --unittest -of spec/run/testparser -Ispec], *parsers, *test_files, "spec/testutils.d")
    end
    expect(result).to be_truthy
  end

  def run
    stdout, stderr, status = Open3.capture3("spec/run/testparser")
    File.binwrite("spec/run/.stderr", stderr)
    File.binwrite("spec/run/.stdout", stdout)
    stderr.sub!(/^.*modules passed unittests\n/, "")
    Results.new(stdout, stderr, status)
  end

  def lines(str)
    str.lines.map(&:chomp)
  end

  def verify_lines(lines, patterns)
    if lines.is_a?(String)
      lines = lines.lines.map(&:chomp)
    end
    patterns.each_with_index do |pattern, i|
      found_index =
        if pattern.is_a?(Regexp)
          lines.find_index {|line| line =~ pattern}
        else
          lines.find_index do |line|
            line.chomp == pattern.chomp
          end
        end
      unless found_index
        $stderr.puts "Lines:"
        $stderr.puts lines
        raise "A line matching #{pattern.inspect} (index #{i}) was not found."
      end
    end
  end

  before(:each) do
    FileUtils.rm_rf("spec/run")
    FileUtils.mkdir_p("spec/run")
  end

  %w[d c].each do |language|

    context "#{language.upcase} language" do

      it "generates a lexer" do
        write_grammar <<EOF
token int /\\d+/;
token plus /\\+/;
token times /\\*/;
drop /\\s+/;
Start -> Foo;
Foo -> int <<
>>
Foo -> plus <<
>>
EOF
        build_parser(language: language)
        compile("spec/test_lexer.#{language}", language: language)
        results = run
        expect(results.stderr).to eq ""
        expect(results.status).to eq 0
      end

      it "detects a lexer error when an unknown character is seen" do
        case language
        when "c"
          write_grammar <<EOF
ptype int;
token int /\\d+/ <<
  int v = 0;
  for (size_t i = 0u; i < match_length; i++)
  {
    v *= 10;
    v += (match[i] - '0');
  }
  $$ = v;
>>
Start -> int <<
  $$ = $1;
>>
EOF
        when "d"
          write_grammar <<EOF
ptype int;
token int /\\d+/ <<
  int v;
  foreach (c; match)
  {
    v *= 10;
    v += (c - '0');
  }
  $$ = v;
>>
Start -> int <<
  $$ = $1;
>>
EOF
        end
        build_parser(language: language)
        compile("spec/test_lexer_unknown_character.#{language}", language: language)
        results = run
        expect(results.stderr).to eq ""
        expect(results.status).to eq 0
      end

      it "generates a parser" do
        write_grammar <<EOF
token plus /\\+/;
token times /\\*/;
token zero /0/;
token one /1/;
Start -> E;
E -> E times B;
E -> E plus B;
E -> B;
B -> zero;
B -> one;
EOF
        build_parser(language: language)
      end

      it "generates a parser that does basic math - user guide example" do
        case language
        when "c"
          write_grammar <<EOF
<<
#include <math.h>
>>

ptype size_t;

token plus /\\+/;
token times /\\*/;
token power /\\*\\*/;
token integer /\\d+/ <<
  size_t v = 0u;
  for (size_t i = 0u; i < match_length; i++)
  {
    v *= 10;
    v += (match[i] - '0');
  }
  $$ = v;
>>
token lparen /\\(/;
token rparen /\\)/;
drop /\\s+/;

Start -> E1 <<
  $$ = $1;
>>
E1 -> E2 <<
  $$ = $1;
>>
E1 -> E1 plus E2 <<
  $$ = $1 + $3;
>>
E2 -> E3 <<
  $$ = $1;
>>
E2 -> E2 times E3 <<
  $$ = $1 * $3;
>>
E3 -> E4 <<
  $$ = $1;
>>
E3 -> E3 power E4 <<
  $$ = (size_t)pow($1, $3);
>>
E4 -> integer <<
  $$ = $1;
>>
E4 -> lparen E1 rparen <<
  $$ = $2;
>>
EOF
        when "d"
          write_grammar <<EOF
<<
import std.math;
>>

ptype ulong;

token plus /\\+/;
token times /\\*/;
token power /\\*\\*/;
token integer /\\d+/ <<
  ulong v;
  foreach (c; match)
  {
    v *= 10;
    v += (c - '0');
  }
  $$ = v;
>>
token lparen /\\(/;
token rparen /\\)/;
drop /\\s+/;

Start -> E1 <<
  $$ = $1;
>>
E1 -> E2 <<
  $$ = $1;
>>
E1 -> E1 plus E2 <<
  $$ = $1 + $3;
>>
E2 -> E3 <<
  $$ = $1;
>>
E2 -> E2 times E3 <<
  $$ = $1 * $3;
>>
E3 -> E4 <<
  $$ = $1;
>>
E3 -> E3 power E4 <<
  $$ = pow($1, $3);
>>
E4 -> integer <<
  $$ = $1;
>>
E4 -> lparen E1 rparen <<
  $$ = $2;
>>
EOF
        end
        build_parser(language: language)
        compile("spec/test_basic_math_grammar.#{language}", language: language)
        results = run
        expect(results.stderr).to eq ""
        expect(results.status).to eq 0
      end

      it "generates an SLR parser" do
        write_grammar <<EOF
token one /1/;
Start -> E;
E -> one E;
E -> one;
EOF
        build_parser(language: language)
      end

      it "distinguishes between multiple identical rules with lookahead symbol" do
        write_grammar <<EOF
token a;
token b;
Start -> R1 a;
Start -> R2 b;
R1 -> a b;
R2 -> a b;
EOF
        build_parser(language: language)
        compile("spec/test_parser_identical_rules_lookahead.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
      end

      it "handles reducing a rule that could be arrived at from multiple states" do
        write_grammar <<EOF
token a;
token b;
drop /\\s+/;
Start -> a R1;
Start -> b R1;
R1 -> b;
EOF
        build_parser(language: language)
        compile("spec/test_parser_rule_from_multiple_states.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
      end

      it "executes user code when matching lexer token" do
        case language
        when "c"
          write_grammar <<EOF
<<
#include <stdio.h>
>>
token abc <<
  printf("abc!\\n");
>>
token def;
Start -> Abcs def;
Abcs -> ;
Abcs -> abc Abcs;
EOF
        when "d"
          write_grammar <<EOF
<<
import std.stdio;
>>
token abc <<
  writeln("abc!");
>>
token def;
Start -> Abcs def;
Abcs -> ;
Abcs -> abc Abcs;
EOF
        end
        build_parser(language: language)
        compile("spec/test_user_code.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
        verify_lines(results.stdout, [
          "abc!",
          "pass1",
          "abc!",
          "abc!",
          "pass2",
        ])
      end

      it "supports a pattern statement" do
        case language
        when "c"
          write_grammar <<EOF
<<
#include <stdio.h>
>>
token abc;
/def/ <<
  printf("def!\\n");
>>
Start -> abc;
EOF
        when "d"
          write_grammar <<EOF
<<
import std.stdio;
>>
token abc;
/def/ <<
  writeln("def!");
>>
Start -> abc;
EOF
        end
        build_parser(language: language)
        compile("spec/test_pattern.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
        verify_lines(results.stdout, [
          "def!",
          "pass1",
          "def!",
          "def!",
          "pass2",
        ])
      end

      it "supports returning tokens from pattern code blocks" do
        case language
        when "c"
          write_grammar <<EOF
<<
#include <stdio.h>
>>
token abc;
/def/ <<
  printf("def!\\n");
>>
/ghi/ <<
  printf("ghi!\\n");
  return $token(abc);
>>
Start -> abc;
EOF
        when "d"
          write_grammar <<EOF
<<
import std.stdio;
>>
token abc;
/def/ <<
  writeln("def!");
>>
/ghi/ <<
  writeln("ghi!");
  return $token(abc);
>>
Start -> abc;
EOF
        end
        build_parser(language: language)
        compile("spec/test_return_token_from_pattern.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
        verify_lines(results.stdout, [
          "def!",
          "ghi!",
          "def!",
        ])
      end

      it "supports lexer modes" do
        case language
        when "c"
          write_grammar <<EOF
<<
#include <stdio.h>
>>
token abc;
token def;
tokenid string;
drop /\\s+/;
/"/ <<
  printf("begin string mode\\n");
  $mode(string);
>>
string: /[^"]+/ <<
  printf("captured string\\n");
>>
string: /"/ <<
  $mode(default);
  return $token(string);
>>
Start -> abc string def;
EOF
        when "d"
          write_grammar <<EOF
<<
import std.stdio;
>>
token abc;
token def;
tokenid string;
drop /\\s+/;
/"/ <<
  writeln("begin string mode");
  $mode(string);
>>
string: /[^"]+/ <<
  writeln("captured string");
>>
string: /"/ <<
  $mode(default);
  return $token(string);
>>
Start -> abc string def;
EOF
        end
        build_parser(language: language)
        compile("spec/test_lexer_modes.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
        verify_lines(results.stdout, [
          "begin string mode",
          "captured string",
          "pass1",
          "begin string mode",
          "captured string",
          "pass2",
        ])
      end

      it "executes user code associated with a parser rule" do
        case language
        when "c"
          write_grammar <<EOF
<<
#include <stdio.h>
>>
token a;
token b;
Start -> A B <<
  printf("Start!\\n");
>>
A -> a <<
  printf("A!\\n");
>>
B -> b <<
  printf("B!\\n");
>>
EOF
        when "d"
          write_grammar <<EOF
<<
import std.stdio;
>>
token a;
token b;
Start -> A B <<
  writeln("Start!");
>>
A -> a <<
  writeln("A!");
>>
B -> b <<
  writeln("B!");
>>
EOF
        end
        build_parser(language: language)
        compile("spec/test_parser_rule_user_code.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
        verify_lines(results.stdout, [
          "A!",
          "B!",
          "Start!",
        ])
      end

      it "parses lists" do
        write_grammar <<EOF
ptype #{language == "c" ? "uint32_t" : "uint"};
token a;
Start -> As <<
  $$ = $1;
>>
As -> <<
  $$ = 0u;
>>
As -> As a <<
  $$ = $1 + 1u;
>>
EOF
        build_parser(language: language)
        compile("spec/test_parsing_lists.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
        expect(results.stderr).to eq ""
      end

      it "fails to generate a parser for a LR(1) grammar that is not LALR" do
        write_grammar <<EOF
token a;
token b;
token c;
token d;
token e;
Start -> a E c;
Start -> a F d;
Start -> b F c;
Start -> b E d;
E -> e;
F -> e;
EOF
        results = build_parser(capture: true, language: language)
        expect(results.status).to_not eq 0
        expect(results.stderr).to match %r{reduce/reduce conflict.*\(E\).*\(F\)}
      end

      it "provides matched text to user code blocks" do
        case language
        when "c"
          write_grammar <<EOF
<<
#include <stdio.h>
#include <stdlib.h>
>>
token id /[a-zA-Z_][a-zA-Z0-9_]*/ <<
  char * t = malloc(match_length + 1);
  strncpy(t, (char *)match, match_length);
  printf("Matched token is %s\\n", t);
  free(t);
>>
Start -> id;
EOF
        when "d"
          write_grammar <<EOF
<<
import std.stdio;
>>
token id /[a-zA-Z_][a-zA-Z0-9_]*/ <<
  writeln("Matched token is ", match);
>>
Start -> id;
EOF
        end
        build_parser(language: language)
        compile("spec/test_lexer_match_text.#{language}", language: language)
        results = run
        expect(results.status).to eq 0
        verify_lines(results.stdout, [
          "Matched token is identifier_123",
          "pass1",
        ])
      end

      it "allows storing a result value for the lexer" do
        case language
        when "c"
          write_grammar <<EOF
ptype uint64_t;
token word /[a-z]+/ <<
  $$ = match_length;
>>
Start -> word <<
  $$ = $1;
>>
EOF
        when "d"
          write_grammar <<EOF
ptype ulong;
token word /[a-z]+/ <<
  $$ = match.length;
>>
Start -> word <<
  $$ = $1;
>>
EOF
        end
        build_parser(language: language)
        compile("spec/test_lexer_result_value.#{language}", language: language)
        results = run
        expect(results.stderr).to eq ""
        expect(results.status).to eq 0
      end

      it "tracks position of parser errors" do
        write_grammar <<EOF
token a;
token num /\\d+/;
drop /\\s+/;
Start -> a num Start;
Start -> a num;
EOF
        build_parser(language: language)
        compile("spec/test_error_positions.#{language}", language: language)
        results = run
        expect(results.stderr).to eq ""
        expect(results.status).to eq 0
      end

      it "allows creating a JSON parser" do
        write_grammar(File.read("spec/json_parser.#{language}.propane"))
        build_parser(language: language)
        compile(["spec/test_parsing_json.#{language}", "spec/json_types.#{language}"], language: language)
      end

      it "allows generating multiple parsers in the same program" do
        write_grammar(<<EOF, name: "myp1")
prefix myp1_;
token a;
token num /\\d+/;
drop /\\s+/;
Start -> a num;
EOF
        build_parser(name: "myp1", language: language)
        write_grammar(<<EOF, name: "myp2")
prefix myp2_;
token b;
token c;
Start -> b c b;
EOF
        build_parser(name: "myp2", language: language)
        compile("spec/test_multiple_parsers.#{language}", parsers: %w[myp1 myp2], language: language)
        results = run
        expect(results.stderr).to eq ""
        expect(results.status).to eq 0
      end
    end
  end
end