refactoring, add participants to sequence diagram, resolves #47

src/plantuml_gui/app.py

@@ -87,6 +87,7 @@
 )
 from .merge import get_index_merge
 from .note import delete_note, edit_note, get_note_line, get_note_text, note_toggle
+from .participant import add_participant
 from .puml_encoder import plantuml_decode, plantuml_encode
 from .render import _create_png_from_uml, _create_svg_from_uml
 from .title import (
@@ -161,6 +162,15 @@ def renderpng():
     )
 
 
+@plantuml.route("/addParticipant", methods=["POST"])
+def addparticipant():
+    data = request.get_json()
+    puml = data["plantuml"]
+    svg = data["svg"]
+    cx = data["cx"]
+    return add_participant(puml, svg, cx)
+
+
 @plantuml.route("/editText", methods=["POST"])
 def edittext():
     data = request.get_json()

src/plantuml_gui/participant.py

@@ -0,0 +1,76 @@
+# SPDX-License-Identifier: MIT
+#
+# MIT License
+#
+# Copyright (c) 2025 Ericsson
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+import re
+from typing import List
+
+from .sequence_classes import Diagram, Participant
+
+
+def add_participant(puml: str, svg: str, cx: int) -> str:
+    """Add a participant at the correct position in the puml code."""
+    diagram = Diagram.from_svg(svg)
+    index_of_closest_participant, closest_participant_cx = find_closest_participant(
+        diagram.participants, cx
+    )
+
+    lines = puml.splitlines()
+
+    if index_of_closest_participant == -1:
+        lines.insert(1, "participant participant1")
+        return "\n".join(lines)
+
+    count = 0
+    index = -1
+    participant_numbers = []
+    for i, line in enumerate(lines):
+        if line.startswith("participant"):
+            match = re.search(r"participant participant(\d+)", line)
+
+            if match:
+                participant_numbers.append(int(match.group(1)))
+
+            if count == index_of_closest_participant:
+                index = i if cx < closest_participant_cx else i + 1
+            count += 1
+
+    next_participant_number = max(participant_numbers, default=0) + 1
+    lines.insert(index, f"participant participant{next_participant_number}")
+    return "\n".join(lines)
+
+
+def find_closest_participant(participants: List[Participant], target_cx: int) -> tuple:
+    """Find the index of the participant with the closest cx value to the target_cx, and return their cx."""
+    closest_index = -1
+    min_distance = float("inf")
+    closest_cx = None
+
+    for index, participant in enumerate(participants):
+        distance = abs(participant.cx - target_cx)
+        if distance < min_distance:
+            min_distance = distance
+            closest_index = index
+            closest_cx = participant.cx
+
+    return closest_index, closest_cx

src/plantuml_gui/sequence_classes.py

@@ -0,0 +1,78 @@
+# SPDX-License-Identifier: MIT
+#
+# MIT License
+#
+# Copyright (c) 2025 Ericsson
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+
+from dataclasses import dataclass, field
+from typing import Dict, List
+
+from pyquery import PyQuery as Pq  # pragma: no cover
+
+
+@dataclass
+class Participant:
+    cx: float
+    cy: float
+
+    def __eq__(self, other):
+        return isinstance(other, Participant) and self.x == other.x
+
+    @classmethod
+    def from_svg(cls, svgtext: str):
+        svg = Pq(svgtext)
+        rect = svg("rect")
+        x = float(rect.attr("x"))
+        y = float(rect.attr("y"))
+        width = float(rect.attr("width"))
+        height = float(rect.attr("height"))
+
+        cx = x + width / 2
+        cy = y + height / 2
+
+        return cls(cx, cy)
+
+
+@dataclass
+class Diagram:
+    participants: List[Participant] = field(default_factory=list)
+
+    @classmethod
+    def from_svg(cls, svgtext: str):
+        svg = Pq(svgtext)
+        diagram = cls()
+
+        diagram._parse_participants(svg)
+
+        return diagram
+
+    def _parse_participants(self, svg):
+        """Extract unique participants based on `cx` value."""
+        unique_participants: Dict[int, Participant] = {}
+
+        for rect in svg("rect").items():
+            participant = Participant.from_svg(rect)
+
+            if participant.cx not in unique_participants:
+                unique_participants[participant.cx] = participant
+
+        self.participants.extend(unique_participants.values())