Add context capture and rules

src/context.py

@@ -0,0 +1,93 @@
+from __future__ import annotations
+
+import re
+from dataclasses import dataclass
+
+
+@dataclass
+class Context:
+    window_id: int
+    app_id: str
+    klass: str
+    instance: str
+    title: str
+
+
+@dataclass
+class ContextRule:
+    match: dict
+    ai_prompt_file: str | None = None
+    ai_enabled: bool | None = None
+    injection_backend: str | None = None
+    tag: str | None = None
+
+
+class ContextProvider:
+    def capture(self) -> Context:
+        raise NotImplementedError
+
+    def is_same_focus(self, ctx: Context) -> bool:
+        raise NotImplementedError
+
+
+class I3Provider(ContextProvider):
+    def __init__(self):
+        import i3ipc
+
+        self.i3 = i3ipc.Connection()
+
+    def _focused(self):
+        node = self.i3.get_tree().find_focused()
+        if node is None:
+            raise RuntimeError("no focused window")
+        return node
+
+    def capture(self) -> Context:
+        node = self._focused()
+        props = node.window_properties or {}
+        return Context(
+            window_id=node.id,
+            app_id=node.app_id or "",
+            klass=props.get("class") or "",
+            instance=props.get("instance") or "",
+            title=node.name or "",
+        )
+
+    def is_same_focus(self, ctx: Context) -> bool:
+        node = self._focused()
+        return node.id == ctx.window_id
+
+
+def _match_text(val: str, needle: str | None) -> bool:
+    if not needle:
+        return True
+    return val == needle
+
+
+def _match_title_contains(title: str, needle: str | None) -> bool:
+    if not needle:
+        return True
+    return needle.lower() in title.lower()
+
+
+def _match_title_regex(title: str, pattern: str | None) -> bool:
+    if not pattern:
+        return True
+    return re.search(pattern, title) is not None
+
+
+def match_rule(ctx: Context, rules: list[ContextRule]) -> ContextRule | None:
+    for rule in rules:
+        match = rule.match or {}
+        if not _match_text(ctx.app_id, match.get("app_id")):
+            continue
+        if not _match_text(ctx.klass, match.get("class")):
+            continue
+        if not _match_text(ctx.instance, match.get("instance")):
+            continue
+        if not _match_title_contains(ctx.title, match.get("title_contains")):
+            continue
+        if not _match_title_regex(ctx.title, match.get("title_regex")):
+            continue
+        return rule
+    return None