#include "runtime/runtime_spec_helper.h"
#include "runtime/helpers/spy_reader.h"

extern "C" const TSLanguage * ts_language_json();
extern "C" const TSLanguage * ts_language_javascript();
extern "C" const TSLanguage * ts_language_arithmetic();

START_TEST

describe("Parser", [&]() {
  TSDocument *doc;
  SpyReader *reader;
  TSNode *root;
  size_t chunk_size;

  before_each([&]() {
    chunk_size = 3;
    reader = nullptr;
    doc = ts_document_make();
  });

  after_each([&]() {
    ts_document_free(doc);
    if (reader)
      delete reader;
  });

  auto set_text = [&](const char *text) {
    reader = new SpyReader(text, chunk_size);
    ts_document_set_input(doc, reader->input());
    root = ts_document_root_node(doc);
    AssertThat(ts_node_size(root).bytes + ts_node_pos(root).bytes, Equals(strlen(text)));
    reader->clear();
  };

  auto insert_text = [&](size_t position, string text) {
    size_t prev_size = ts_node_size(root).bytes + ts_node_pos(root).bytes;
    AssertThat(reader->insert(position, text), IsTrue());
    ts_document_edit(doc, { position, 0, text.length() });

    root = ts_document_root_node(doc);
    size_t new_size = ts_node_size(root).bytes + ts_node_pos(root).bytes;
    AssertThat(new_size, Equals(prev_size + text.size()));
  };

  auto delete_text = [&](size_t position, size_t length) {
    size_t prev_size = ts_node_size(root).bytes + ts_node_pos(root).bytes;
    AssertThat(reader->erase(position, length), IsTrue());
    ts_document_edit(doc, { position, length, 0 });

    root = ts_document_root_node(doc);
    size_t new_size = ts_node_size(root).bytes + ts_node_pos(root).bytes;
    AssertThat(new_size, Equals(prev_size - length));
  };

  describe("handling errors", [&]() {
    before_each([&]() {
      ts_document_set_language(doc, ts_language_json());
    });

    describe("when the error occurs at the beginning of a token", [&]() {
      it("computes the error node's size and position correctly", [&]() {
        set_text("  [123,  @@@@@,   true]");

        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT (array (number) (ERROR '@') (true)))"));

        TSNode *array = ts_node_child(root, 0);
        TSNode *error = ts_node_child(array, 1);
        TSNode *last = ts_node_child(array, 2);

        AssertThat(ts_node_name(error), Equals("error"));
        AssertThat(ts_node_pos(error).bytes, Equals(strlen("  [123,  ")))
        AssertThat(ts_node_size(error).bytes, Equals(strlen("@@@@@")))

        AssertThat(ts_node_name(last), Equals("true"));
        AssertThat(ts_node_pos(last).bytes, Equals(strlen("  [123,  @@@@@,   ")))

        ts_node_release(last);
        ts_node_release(error);
        ts_node_release(array);
      });
    });

    describe("when the error occurs in the middle of a token", [&]() {
      it("computes the error node's size and position correctly", [&]() {
        set_text("  [123, faaaaalse, true]");

        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT (array (number) (ERROR 'a') (true)))"));

        TSNode *array = ts_node_child(root, 0);
        TSNode *error = ts_node_child(array, 1);
        TSNode *last = ts_node_child(array, 2);

        AssertThat(ts_node_name(error), Equals("error"));
        AssertThat(ts_node_pos(error).bytes, Equals(strlen("  [123, ")))
        AssertThat(ts_node_size(error).bytes, Equals(strlen("faaaaalse")))

        AssertThat(ts_node_name(last), Equals("true"));
        AssertThat(ts_node_pos(last).bytes, Equals(strlen("  [123, faaaaalse, ")));

        ts_node_release(last);
        ts_node_release(error);
        ts_node_release(array);
      });
    });

    describe("when the error occurs after one or more tokens", [&]() {
      it("computes the error node's size and position correctly", [&]() {
        set_text("  [123, true false, true]");

        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT (array (number) (ERROR 'f') (true)))"));

        TSNode *array = ts_node_child(root, 0);
        TSNode *error = ts_node_child(array, 1);
        TSNode *last = ts_node_child(array, 2);

        AssertThat(ts_node_name(error), Equals("error"));
        AssertThat(ts_node_pos(error).bytes, Equals(strlen("  [123, ")));
        AssertThat(ts_node_size(error).bytes, Equals(strlen("true false")));

        AssertThat(ts_node_name(last), Equals("true"));
        AssertThat(ts_node_pos(last).bytes, Equals(strlen("  [123, true false, ")));

        ts_node_release(last);
        ts_node_release(error);
        ts_node_release(array);
      });
    });

    describe("when the error is an empty string", [&]() {
      it("computes the error node's size and position correctly", [&]() {
        set_text("  [123, , true]");

        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT (array (number) (ERROR ',') (true)))"));

        TSNode *array = ts_node_child(root, 0);
        TSNode *error = ts_node_child(array, 1);
        TSNode *last = ts_node_child(array, 2);

        AssertThat(ts_node_name(error), Equals("error"));
        AssertThat(ts_node_pos(error).bytes, Equals(strlen("  [123, ")));
        AssertThat(ts_node_size(error).bytes, Equals<size_t>(0))

        AssertThat(ts_node_name(last), Equals("true"));
        AssertThat(ts_node_pos(last).bytes, Equals(strlen("  [123, , ")));

        ts_node_release(last);
        ts_node_release(error);
        ts_node_release(array);
      });
    });
  });

  describe("handling ubiquitous tokens", [&]() {
    // In the javascript example grammar, ASI works by using newlines as
    // terminators in statements, but also as ubiquitous tokens.
    before_each([&]() {
      ts_document_set_language(doc, ts_language_javascript());
    });

    describe("when the token appears as part of a grammar rule", [&]() {
      it("is incorporated into the tree", [&]() {
        set_text("fn()\n");

        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT (expression_statement (function_call (identifier))))"));
      });
    });

    describe("when the token appears somewhere else", [&]() {
      it("is incorporated into the tree", [&]() {
        set_text(
          "fn()\n"
          "  .otherFn();");

        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT "
              "(expression_statement (function_call "
                "(property_access (function_call (identifier)) (identifier)))))"));
      });
    });

    describe("when several ubiquitous tokens appear in a row", [&]() {
      it("is incorporated into the tree", [&]() {
        set_text(
          "fn()\n\n"
          "// This is a comment"
          "\n\n"
          ".otherFn();");

        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT "
              "(expression_statement (function_call "
                "(property_access (function_call (identifier)) "
                  "(comment) "
                  "(identifier)))))"));
      });
    });
  });

  describe("editing", [&]() {
    before_each([&]() {
      ts_document_set_language(doc, ts_language_arithmetic());
    });

    describe("inserting text", [&]() {
      describe("new tokens near the end of the input", [&]() {
        before_each([&]() {
          set_text("x ^ (100 + abc)");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (exponent "
                "(variable) "
                "(group (sum (number) (variable)))))"));

          insert_text(strlen("x ^ (100 + abc"), " * 5");
        });

        it("updates the parse tree", [&]() {
          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (exponent "
                "(variable) "
                "(group (sum (number) (product (variable) (number))))))"));
        });

        it("re-reads only the changed portion of the input", [&]() {
          AssertThat(reader->strings_read, Equals(vector<string>({ " abc * 5)" })));
        });
      });

      describe("introducing an error", [&]() {
        it("gives the error the right size", [&]() {
          ts_document_set_language(doc, ts_language_javascript());

          set_text("var x = y;");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (var_declaration "
                  "(identifier) (identifier)))"));

          insert_text(strlen("var x = y"), " *");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (var_declaration (ERROR ';')))"));

          insert_text(strlen("var x = y *"), " z");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (var_declaration "
                  "(identifier) (math_op (identifier) (identifier))))"));
        });
      });

      describe("new tokens near the beginning of the input", [&]() {
        before_each([&]() {
          set_text("123 * 456");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (product (number) (number)))"));

          insert_text(strlen("123"), " + 5 ");
        });

        it("updates the parse tree", [&]() {
          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (sum (number) (product (number) (number))))"));
        });

        it_skip("re-reads only the changed portion of the input", [&]() {
          AssertThat(reader->strings_read, Equals(vector<string>({ "\"key2\": 4, " })));
        });
      });

      describe("into the middle of an existing token", [&]() {
        before_each([&]() {
          set_text("abc * 123");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (product (variable) (number)))"));

          insert_text(strlen("ab"), "XYZ");
        });

        it("updates the parse tree", [&]() {
          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (product (variable) (number)))"));

          TSNode *node = ts_node_find_for_pos(root, 1);
          AssertThat(ts_node_name(node), Equals("variable"));
          AssertThat(ts_node_size(node).bytes, Equals(strlen("abXYZc")));
          ts_node_release(node);
        });
      });

      describe("at the end of an existing token", [&]() {
        before_each([&]() {
          set_text("abc * 123");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (product (variable) (number)))"));

          insert_text(strlen("abc"), "XYZ");
        });

        it("updates the parse tree", [&]() {
          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (product (variable) (number)))"));

          TSNode *node = ts_node_find_for_pos(root, 1);
          AssertThat(ts_node_name(node), Equals("variable"));
          AssertThat(ts_node_size(node).bytes, Equals(strlen("abcXYZ")));
          ts_node_release(node);
        });
      });

      describe("with non-ascii characters", [&]() {
        before_each([&]() {
          // αβδ + 1
          set_text("\u03b1\u03b2\u03b4 + 1");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (sum (variable) (number)))"));

          // αβδ + ψ1
          insert_text(strlen("abd + "), "\u03c8");
        });

        it("inserts the text according to the UTF8 character index", [&]() {
          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (sum (variable) (variable)))"));
        });
      });
    });

    describe("deleting text", [&]() {
      describe("when a critical token is removed", [&]() {
        before_each([&]() {
          set_text("123 * 456");

          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (product (number) (number)))"));

          delete_text(strlen("123 "), 2);
        });

        it("updates the parse tree, creating an error", [&]() {
          AssertThat(ts_node_string(root), Equals(
              "(DOCUMENT (number) (ERROR '4'))"));
        });
      });
    });

    describe("editing text inside a node containing a ubiquitous token", [&]() {
      before_each([&]() {
        set_text("123 *\n"
            "# a-comment\n"
            "abc");

        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT (product (number) (comment) (variable)))"));

        insert_text(
            strlen("123 *\n"
                "# a-comment\n"
                "abc"),
            "XYZ");
      });

      it("updates the parse tree", [&]() {
        AssertThat(ts_node_string(root), Equals(
            "(DOCUMENT (product (number) (comment) (variable)))"));
      });
    });
  });

  describe("lexing", [&]() {
    before_each([&]() {
      ts_document_set_language(doc, ts_language_arithmetic());
    });

    describe("handling tokens containing wildcard patterns (e.g. comments)", [&]() {
      it("terminates them at the end of the document", [&]() {
        set_text("x # this is a comment");

        AssertThat(ts_node_string(root), Equals("(DOCUMENT "
            "(expression (variable) (comment)))"));

        TSNode *expression = ts_node_child(root, 0);
        TSNode *comment = ts_node_child(expression, 1);

        AssertThat(ts_node_size(comment).bytes, Equals(strlen("# this is a comment")));

        ts_node_release(expression);
        ts_node_release(comment);
      });
    });

    it("recognizes UTF8 characters as single characters", [&]() {
      // x # ΩΩΩ — ΔΔ
      set_text("x # \u03A9\u03A9\u03A9 \u2014 \u0394\u0394");

      AssertThat(ts_node_string(root), Equals("(DOCUMENT "
        "(expression (variable) (comment)))"));

      AssertThat(ts_node_size(root).chars, Equals(strlen("x # OOO - DD")));
      AssertThat(ts_node_size(root).bytes, Equals(strlen("x # \u03A9\u03A9\u03A9 \u2014 \u0394\u0394")));
    });
  });
});

END_TEST