feat(core): implement domain dataclasses for issue #5

- Create core/__init__.py
- Create core/models.py with all domain dataclasses:
  - Bounty (base class)
  - GroupBounty (extends Bounty)
  - PersonalBounty (extends Bounty)
  - TrackedBounty
  - GroupData
  - TrackingData
  - UserData
- Create tests/test_models.py with 15 passing tests

Fixes #5

core/__init__.py

@@ -0,0 +1,21 @@
+"""Core domain models for JIGAIDO."""
+
+from core.models import (
+    Bounty,
+    GroupBounty,
+    PersonalBounty,
+    TrackedBounty,
+    GroupData,
+    TrackingData,
+    UserData,
+)
+
+__all__ = [
+    "Bounty",
+    "GroupBounty",
+    "PersonalBounty",
+    "TrackedBounty",
+    "GroupData",
+    "TrackingData",
+    "UserData",
+]

core/models.py

@@ -0,0 +1,63 @@
+"""Domain dataclasses for JIGAIDO bounty tracker."""
+
+from dataclasses import dataclass
+from typing import Optional
+
+
+@dataclass
+class Bounty:
+    """Base bounty with common fields."""
+
+    id: int
+    text: Optional[str]
+    link: Optional[str]
+    due_date_ts: Optional[int]
+    created_at: int
+
+
+@dataclass
+class GroupBounty(Bounty):
+    """Bounty created in a group context."""
+
+    created_by_user_id: int
+
+
+@dataclass
+class PersonalBounty(Bounty):
+    """Bounty created in DM/personal context."""
+
+    pass
+
+
+@dataclass
+class TrackedBounty:
+    """A bounty that a user is tracking."""
+
+    bounty_id: int
+    created_at: int
+
+
+@dataclass
+class GroupData:
+    """All data for a group."""
+
+    group_id: int
+    bounties: list[GroupBounty]
+    next_id: int
+
+
+@dataclass
+class TrackingData:
+    """User tracking data within a group."""
+
+    user_id: int
+    tracked: list[TrackedBounty]
+
+
+@dataclass
+class UserData:
+    """All personal bounties for a user (DM mode)."""
+
+    user_id: int
+    bounties: list[PersonalBounty]
+    next_id: int

tests/test_models.py

@@ -0,0 +1,167 @@
+"""Tests for core/models.py — domain dataclasses."""
+
+import time
+
+import pytest
+
+from core.models import (
+    Bounty,
+    GroupBounty,
+    PersonalBounty,
+    TrackedBounty,
+    GroupData,
+    TrackingData,
+    UserData,
+)
+
+
+class TestBounty:
+    def test_create_bounty(self):
+        b = Bounty(
+            id=1,
+            text="Fix the bug",
+            link="https://github.com/example/repo/issues/1",
+            due_date_ts=1735689600,
+            created_at=1735603200,
+        )
+        assert b.id == 1
+        assert b.text == "Fix the bug"
+        assert b.link == "https://github.com/example/repo/issues/1"
+        assert b.due_date_ts == 1735689600
+        assert b.created_at == 1735603200
+
+    def test_bounty_optional_fields_can_be_none(self):
+        b = Bounty(
+            id=1,
+            text=None,
+            link=None,
+            due_date_ts=None,
+            created_at=0,
+        )
+        assert b.text is None
+        assert b.link is None
+        assert b.due_date_ts is None
+
+    def test_bounty_comparison(self):
+        b1 = Bounty(id=1, text="a", link=None, due_date_ts=None, created_at=0)
+        b2 = Bounty(id=1, text="a", link=None, due_date_ts=None, created_at=0)
+        assert b1 == b2
+
+
+class TestGroupBounty:
+    def test_create_group_bounty(self):
+        gb = GroupBounty(
+            id=1,
+            text="Group task",
+            link=None,
+            due_date_ts=None,
+            created_at=0,
+            created_by_user_id=123456,
+        )
+        assert gb.id == 1
+        assert gb.text == "Group task"
+        assert gb.created_by_user_id == 123456
+
+    def test_group_bounty_inherits_from_bounty(self):
+        gb = GroupBounty(
+            id=1,
+            text="Task",
+            link="https://example.com",
+            due_date_ts=int(time.time()),
+            created_at=0,
+            created_by_user_id=999,
+        )
+        assert isinstance(gb, Bounty)
+
+
+class TestPersonalBounty:
+    def test_create_personal_bounty(self):
+        pb = PersonalBounty(
+            id=1,
+            text="Personal task",
+            link=None,
+            due_date_ts=None,
+            created_at=0,
+        )
+        assert pb.id == 1
+        assert pb.text == "Personal task"
+
+    def test_personal_bounty_inherits_from_bounty(self):
+        pb = PersonalBounty(
+            id=1,
+            text="Task",
+            link=None,
+            due_date_ts=None,
+            created_at=0,
+        )
+        assert isinstance(pb, Bounty)
+
+
+class TestTrackedBounty:
+    def test_create_tracked_bounty(self):
+        tb = TrackedBounty(bounty_id=5, created_at=1735600000)
+        assert tb.bounty_id == 5
+        assert tb.created_at == 1735600000
+
+    def test_tracked_bounty_comparison(self):
+        tb1 = TrackedBounty(bounty_id=1, created_at=0)
+        tb2 = TrackedBounty(bounty_id=1, created_at=0)
+        assert tb1 == tb2
+
+
+class TestGroupData:
+    def test_create_group_data(self):
+        gd = GroupData(
+            group_id=-1001,
+            bounties=[],
+            next_id=1,
+        )
+        assert gd.group_id == -1001
+        assert gd.bounties == []
+        assert gd.next_id == 1
+
+    def test_group_data_with_bounties(self):
+        gb = GroupBounty(
+            id=1,
+            text="Task",
+            link=None,
+            due_date_ts=None,
+            created_at=0,
+            created_by_user_id=123,
+        )
+        gd = GroupData(group_id=-1001, bounties=[gb], next_id=2)
+        assert len(gd.bounties) == 1
+        assert gd.bounties[0].text == "Task"
+
+
+class TestTrackingData:
+    def test_create_tracking_data(self):
+        td = TrackingData(user_id=123456, tracked=[])
+        assert td.user_id == 123456
+        assert td.tracked == []
+
+    def test_tracking_data_with_tracked(self):
+        tb = TrackedBounty(bounty_id=5, created_at=0)
+        td = TrackingData(user_id=123, tracked=[tb])
+        assert len(td.tracked) == 1
+        assert td.tracked[0].bounty_id == 5
+
+
+class TestUserData:
+    def test_create_user_data(self):
+        ud = UserData(user_id=123456, bounties=[], next_id=1)
+        assert ud.user_id == 123456
+        assert ud.bounties == []
+        assert ud.next_id == 1
+
+    def test_user_data_with_bounties(self):
+        pb = PersonalBounty(
+            id=1,
+            text="My task",
+            link=None,
+            due_date_ts=None,
+            created_at=0,
+        )
+        ud = UserData(user_id=123, bounties=[pb], next_id=2)
+        assert len(ud.bounties) == 1
+        assert ud.bounties[0].text == "My task"