Add mermaidjs as format output for pyreverse (#5272)

add mermaid js printer, fix accepted output format without graphviz
Make an adapter for package graph, use class until mermaid don't
add a package diagram type. Add mmd and html formats to additional commands

13 files changed, 288 insertions, 3 deletions

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 7e692843b..429c04b33 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -6,7 +6,7 @@ repos:
     rev: v4.0.1
     hooks:
       - id: trailing-whitespace
-        exclude: "tests/functional/t/trailing_whitespaces.py"
+        exclude: "tests/functional/t/trailing_whitespaces.py|tests/pyreverse/data/.*.html"
       - id: end-of-file-fixer
         exclude: "tests/functional/m/missing/missing_final_newline.py|tests/functional/t/trailing_newlines.py"
   - repo: https://github.com/myint/autoflake
@@ -94,3 +94,4 @@ repos:
     hooks:
       - id: prettier
         args: [--prose-wrap=always, --print-width=88]
+        exclude: tests(/.*)*/data
diff --git a/ChangeLog b/ChangeLog
index 4dd010abb..c55294e16 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,8 @@ What's New in Pylint 2.13.0?
 ============================
 Release date: TBA
 
+* Pyreverse - add output in mermaidjs format
+
 ..
   Put new features here and also in 'doc/whatsnew/2.13.rst'
 
diff --git a/doc/additional_commands/index.rst b/doc/additional_commands/index.rst
index e4c92cab3..b8ebb15cb 100644
--- a/doc/additional_commands/index.rst
+++ b/doc/additional_commands/index.rst
@@ -9,7 +9,7 @@ Pyreverse
 ---------
 
 ``pyreverse`` analyzes your source code and generates package and class diagrams.
-It supports output to ``.dot``/``.gv``, ``.vcg`` and ``.puml``/``.plantuml`` (PlantUML) file formats.
+It supports output to ``.dot``/``.gv``, ``.vcg``, ``.puml``/``.plantuml`` (PlantUML) and ``.mmd``/``.html`` (MermaidJS) file formats.
 If Graphviz (or the ``dot`` command) is installed, all `output formats supported by Graphviz <https://graphviz.org/docs/outputs/>`_
 can be used as well. In this case, ``pyreverse`` first generates a temporary ``.gv`` file, which is then
 fed to Graphviz to generate the final image.
diff --git a/doc/whatsnew/2.13.rst b/doc/whatsnew/2.13.rst
index 378b4103b..60099b67e 100644
--- a/doc/whatsnew/2.13.rst
+++ b/doc/whatsnew/2.13.rst
@@ -17,6 +17,8 @@ Removed checkers
 Extensions
 ==========
 
+* Pyreverse - add output in mermaid-js format and html which is an mermaid js diagram with html boilerplate
+
 Other Changes
 =============
 
diff --git a/pylint/pyreverse/main.py b/pylint/pyreverse/main.py
index fc302149a..c48b9f3c3 100644
--- a/pylint/pyreverse/main.py
+++ b/pylint/pyreverse/main.py
@@ -206,7 +206,14 @@ class Run(ConfigurationMixIn):
         super().__init__(usage=__doc__)
         insert_default_options()
         args = self.load_command_line_configuration(args)
-        if self.config.output_format not in ("dot", "vcg", "puml", "plantuml"):
+        if self.config.output_format not in (
+            "dot",
+            "vcg",
+            "puml",
+            "plantuml",
+            "mmd",
+            "html",
+        ):
             check_graphviz_availability()
 
         sys.exit(self.run(args))
diff --git a/pylint/pyreverse/mermaidjs_printer.py b/pylint/pyreverse/mermaidjs_printer.py
new file mode 100644
index 000000000..c8214ab8e
--- /dev/null
+++ b/pylint/pyreverse/mermaidjs_printer.py
@@ -0,0 +1,110 @@
+# Copyright (c) 2021 Antonio Quarta <andi.finkler@gmail.com>
+
+# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+# For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
+
+"""
+Class to generate files in mermaidjs format
+"""
+from typing import Dict, Optional
+
+from pylint.pyreverse.printer import EdgeType, NodeProperties, NodeType, Printer
+from pylint.pyreverse.utils import get_annotation_label
+
+
+class MermaidJSPrinter(Printer):
+    """Printer for MermaidJS diagrams"""
+
+    DEFAULT_COLOR = "black"
+
+    NODES: Dict[NodeType, str] = {
+        NodeType.CLASS: "class",
+        NodeType.INTERFACE: "class",
+        NodeType.PACKAGE: "class",
+    }
+    ARROWS: Dict[EdgeType, str] = {
+        EdgeType.INHERITS: "--|>",
+        EdgeType.IMPLEMENTS: "..|>",
+        EdgeType.ASSOCIATION: "--*",
+        EdgeType.USES: "-->",
+    }
+
+    def _open_graph(self) -> None:
+        """Emit the header lines"""
+        self.emit("classDiagram")
+        self._inc_indent()
+
+    def emit_node(
+        self,
+        name: str,
+        type_: NodeType,
+        properties: Optional[NodeProperties] = None,
+    ) -> None:
+        """Create a new node. Nodes can be classes, packages, participants etc."""
+        if properties is None:
+            properties = NodeProperties(label=name)
+        stereotype = "~~Interface~~" if type_ is NodeType.INTERFACE else ""
+        nodetype = self.NODES[type_]
+        body = []
+        if properties.attrs:
+            body.extend(properties.attrs)
+        if properties.methods:
+            for func in properties.methods:
+                args = self._get_method_arguments(func)
+                line = f"{func.name}({', '.join(args)})"
+                if func.returns:
+                    line += " -> " + get_annotation_label(func.returns)
+                body.append(line)
+        name = name.split(".")[-1]
+        self.emit(f"{nodetype} {name}{stereotype} {{")
+        self._inc_indent()
+        for line in body:
+            self.emit(line)
+        self._dec_indent()
+        self.emit("}")
+
+    def emit_edge(
+        self,
+        from_node: str,
+        to_node: str,
+        type_: EdgeType,
+        label: Optional[str] = None,
+    ) -> None:
+        """Create an edge from one node to another to display relationships."""
+        from_node = from_node.split(".")[-1]
+        to_node = to_node.split(".")[-1]
+        edge = f"{from_node} {self.ARROWS[type_]} {to_node}"
+        if label:
+            edge += f" : {label}"
+        self.emit(edge)
+
+    def _close_graph(self) -> None:
+        """Emit the lines needed to properly close the graph."""
+        self._dec_indent()
+
+
+class HTMLMermaidJSPrinter(MermaidJSPrinter):
+    """Printer for MermaidJS diagrams wrapped in an html boilerplate"""
+
+    HTML_OPEN_BOILERPLATE = """<html>
+  <body>
+    <script src="https://cdn.jsdelivr.net/npm/mermaid/dist/mermaid.min.js"></script>
+      <div class="mermaid">
+    """
+    HTML_CLOSE_BOILERPLATE = """
+       </div>
+  </body>
+</html>
+"""
+    GRAPH_INDENT_LEVEL = 4
+
+    def _open_graph(self) -> None:
+        self.emit(self.HTML_OPEN_BOILERPLATE)
+        for _ in range(self.GRAPH_INDENT_LEVEL):
+            self._inc_indent()
+        super()._open_graph()
+
+    def _close_graph(self) -> None:
+        for _ in range(self.GRAPH_INDENT_LEVEL):
+            self._dec_indent()
+        self.emit(self.HTML_CLOSE_BOILERPLATE)
diff --git a/pylint/pyreverse/printer_factory.py b/pylint/pyreverse/printer_factory.py
index 73200c35d..bdcaf0869 100644
--- a/pylint/pyreverse/printer_factory.py
+++ b/pylint/pyreverse/printer_factory.py
@@ -8,6 +8,7 @@
 from typing import Dict, Type
 
 from pylint.pyreverse.dot_printer import DotPrinter
+from pylint.pyreverse.mermaidjs_printer import HTMLMermaidJSPrinter, MermaidJSPrinter
 from pylint.pyreverse.plantuml_printer import PlantUmlPrinter
 from pylint.pyreverse.printer import Printer
 from pylint.pyreverse.vcg_printer import VCGPrinter
@@ -16,6 +17,8 @@ filetype_to_printer: Dict[str, Type[Printer]] = {
     "vcg": VCGPrinter,
     "plantuml": PlantUmlPrinter,
     "puml": PlantUmlPrinter,
+    "mmd": MermaidJSPrinter,
+    "html": HTMLMermaidJSPrinter,
     "dot": DotPrinter,
 }
 
diff --git a/tests/pyreverse/conftest.py b/tests/pyreverse/conftest.py
index 9536fbcb0..c83e74cbd 100644
--- a/tests/pyreverse/conftest.py
+++ b/tests/pyreverse/conftest.py
@@ -43,6 +43,22 @@ def colorized_puml_config() -> PyreverseConfig:
     )
 
 
+@pytest.fixture()
+def mmd_config() -> PyreverseConfig:
+    return PyreverseConfig(
+        output_format="mmd",
+        colorized=False,
+    )
+
+
+@pytest.fixture()
+def html_config() -> PyreverseConfig:
+    return PyreverseConfig(
+        output_format="html",
+        colorized=False,
+    )
+
+
 @pytest.fixture(scope="session")
 def get_project() -> Callable:
     def _get_project(module: str, name: Optional[str] = "No Name") -> Project:
diff --git a/tests/pyreverse/data/classes_No_Name.html b/tests/pyreverse/data/classes_No_Name.html
new file mode 100644
index 000000000..3f81c340e
--- /dev/null
+++ b/tests/pyreverse/data/classes_No_Name.html
@@ -0,0 +1,47 @@
+<html>
+  <body>
+    <script src="https://cdn.jsdelivr.net/npm/mermaid/dist/mermaid.min.js"></script>
+      <div class="mermaid">
+
+        classDiagram
+          class Ancestor {
+            attr : str
+            cls_member
+            get_value()
+            set_value(value)
+          }
+          class CustomException {
+          }
+          class DoNothing {
+          }
+          class DoNothing2 {
+          }
+          class DoSomething {
+            my_int : Optional[int]
+            my_int_2 : Optional[int]
+            my_string : str
+            do_it(new_int: int) -> int
+          }
+          class Interface {
+            get_value()
+            set_value(value)
+          }
+          class PropertyPatterns {
+            prop1
+            prop2
+          }
+          class Specialization {
+            TYPE : str
+            relation
+            relation2
+            top : str
+          }
+          Specialization --|> Ancestor
+          Ancestor ..|> Interface
+          DoNothing --* Ancestor : cls_member
+          DoNothing --* Specialization : relation
+          DoNothing2 --* Specialization : relation2
+
+       </div>
+  </body>
+</html>
diff --git a/tests/pyreverse/data/classes_No_Name.mmd b/tests/pyreverse/data/classes_No_Name.mmd
new file mode 100644
index 000000000..d2ac9839d
--- /dev/null
+++ b/tests/pyreverse/data/classes_No_Name.mmd
@@ -0,0 +1,38 @@
+classDiagram
+  class Ancestor {
+    attr : str
+    cls_member
+    get_value()
+    set_value(value)
+  }
+  class CustomException {
+  }
+  class DoNothing {
+  }
+  class DoNothing2 {
+  }
+  class DoSomething {
+    my_int : Optional[int]
+    my_int_2 : Optional[int]
+    my_string : str
+    do_it(new_int: int) -> int
+  }
+  class Interface {
+    get_value()
+    set_value(value)
+  }
+  class PropertyPatterns {
+    prop1
+    prop2
+  }
+  class Specialization {
+    TYPE : str
+    relation
+    relation2
+    top : str
+  }
+  Specialization --|> Ancestor
+  Ancestor ..|> Interface
+  DoNothing --* Ancestor : cls_member
+  DoNothing --* Specialization : relation
+  DoNothing2 --* Specialization : relation2
diff --git a/tests/pyreverse/data/packages_No_Name.html b/tests/pyreverse/data/packages_No_Name.html
new file mode 100644
index 000000000..128f8d1a4
--- /dev/null
+++ b/tests/pyreverse/data/packages_No_Name.html
@@ -0,0 +1,19 @@
+<html>
+  <body>
+    <script src="https://cdn.jsdelivr.net/npm/mermaid/dist/mermaid.min.js"></script>
+      <div class="mermaid">
+
+        classDiagram
+          class data {
+          }
+          class clientmodule_test {
+          }
+          class property_pattern {
+          }
+          class suppliermodule_test {
+          }
+          clientmodule_test --> suppliermodule_test
+
+       </div>
+  </body>
+</html>
diff --git a/tests/pyreverse/data/packages_No_Name.mmd b/tests/pyreverse/data/packages_No_Name.mmd
new file mode 100644
index 000000000..e8b02d070
--- /dev/null
+++ b/tests/pyreverse/data/packages_No_Name.mmd
@@ -0,0 +1,10 @@
+classDiagram
+  class data {
+  }
+  class clientmodule_test {
+  }
+  class property_pattern {
+  }
+  class suppliermodule_test {
+  }
+  clientmodule_test --> suppliermodule_test
diff --git a/tests/pyreverse/test_writer.py b/tests/pyreverse/test_writer.py
index 142ba04a0..bbfd36411 100644
--- a/tests/pyreverse/test_writer.py
+++ b/tests/pyreverse/test_writer.py
@@ -58,6 +58,8 @@ COLORIZED_DOT_FILES = ["packages_colorized.dot", "classes_colorized.dot"]
 VCG_FILES = ["packages_No_Name.vcg", "classes_No_Name.vcg"]
 PUML_FILES = ["packages_No_Name.puml", "classes_No_Name.puml"]
 COLORIZED_PUML_FILES = ["packages_colorized.puml", "classes_colorized.puml"]
+MMD_FILES = ["packages_No_Name.mmd", "classes_No_Name.mmd"]
+HTML_FILES = ["packages_No_Name.html", "classes_No_Name.html"]
 
 
 class Config:
@@ -121,6 +123,22 @@ def setup_colorized_puml(
     yield from _setup(project, colorized_puml_config, writer)
 
 
+@pytest.fixture()
+def setup_mmd(mmd_config: PyreverseConfig, get_project: Callable) -> Iterator:
+    writer = DiagramWriter(mmd_config)
+
+    project = get_project(TEST_DATA_DIR)
+    yield from _setup(project, mmd_config, writer)
+
+
+@pytest.fixture()
+def setup_html(html_config: PyreverseConfig, get_project: Callable) -> Iterator:
+    writer = DiagramWriter(html_config)
+
+    project = get_project(TEST_DATA_DIR)
+    yield from _setup(project, html_config, writer)
+
+
 def _setup(
     project: Project, config: PyreverseConfig, writer: DiagramWriter
 ) -> Iterator:
@@ -164,6 +182,18 @@ def test_puml_files(generated_file: str) -> None:
     _assert_files_are_equal(generated_file)
 
 
+@pytest.mark.usefixtures("setup_mmd")
+@pytest.mark.parametrize("generated_file", MMD_FILES)
+def test_mmd_files(generated_file: str) -> None:
+    _assert_files_are_equal(generated_file)
+
+
+@pytest.mark.usefixtures("setup_html")
+@pytest.mark.parametrize("generated_file", HTML_FILES)
+def test_html_files(generated_file: str) -> None:
+    _assert_files_are_equal(generated_file)
+
+
 @pytest.mark.usefixtures("setup_colorized_puml")
 @pytest.mark.parametrize("generated_file", COLORIZED_PUML_FILES)
 def test_colorized_puml_files(generated_file: str) -> None: