feat: add local zero-cost configuration

src/javis/config/local_config.py

@@ -0,0 +1,113 @@
+"""Non-secret local TOML configuration."""
+
+from __future__ import annotations
+
+import os
+import tomllib
+from collections.abc import Mapping
+from pathlib import Path
+
+
+class LocalConfigError(ValueError):
+    """A local configuration file is malformed or unsafe to replace."""
+
+
+def _mapping(value: object, section: str) -> Mapping[str, object]:
+    if value is None:
+        return {}
+    if not isinstance(value, dict):
+        raise LocalConfigError(f"TOML-Abschnitt [{section}] muss eine Tabelle sein.")
+    return value
+
+
+def _value(values: Mapping[str, object], name: str) -> str | None:
+    value = values.get(name)
+    if value is None:
+        return None
+    if isinstance(value, bool):
+        return "true" if value else "false"
+    if isinstance(value, (str, int, float)):
+        return str(value)
+    raise LocalConfigError(f"TOML-Wert '{name}' hat einen nicht unterstützten Typ.")
+
+
+def load_local_defaults(path: Path) -> dict[str, str]:
+    """Translate the supported non-secret TOML fields to settings inputs."""
+    if not path.exists():
+        return {}
+    try:
+        with path.open("rb") as handle:
+            document = tomllib.load(handle)
+    except (OSError, tomllib.TOMLDecodeError) as exc:
+        raise LocalConfigError(f"Lokale Konfiguration ist ungültig: {path}") from exc
+
+    providers = _mapping(document.get("providers"), "providers")
+    gemini = _mapping(providers.get("gemini"), "providers.gemini")
+    ollama = _mapping(providers.get("ollama"), "providers.ollama")
+    translated: dict[str, str] = {}
+    fields = (
+        (providers, "active", "JAVIS_PROVIDER_MODE"),
+        (ollama, "model", "JAVIS_MODEL"),
+        (ollama, "base_url", "JAVIS_OLLAMA_URL"),
+        (ollama, "timeout_seconds", "JAVIS_MODEL_TIMEOUT"),
+        (gemini, "enabled", "JAVIS_GEMINI_ENABLED"),
+        (gemini, "model", "JAVIS_GEMINI_MODEL"),
+        (gemini, "optional_model", "JAVIS_GEMINI_OPTIONAL_MODEL"),
+        (gemini, "free_only", "JAVIS_FREE_ONLY"),
+        (
+            gemini,
+            "billing_confirmed_disabled",
+            "JAVIS_GEMINI_BILLING_CONFIRMED_DISABLED",
+        ),
+        (gemini, "max_requests_per_day", "JAVIS_MAX_CLOUD_REQUESTS_PER_DAY"),
+        (gemini, "max_input_chars", "JAVIS_MAX_CLOUD_INPUT_CHARS"),
+        (gemini, "max_output_tokens", "JAVIS_MAX_CLOUD_OUTPUT_TOKENS"),
+        (gemini, "timeout_seconds", "JAVIS_GEMINI_TIMEOUT"),
+        (gemini, "max_attempts", "JAVIS_GEMINI_MAX_ATTEMPTS"),
+        (gemini, "max_context_messages", "JAVIS_MAX_CLOUD_CONTEXT_MESSAGES"),
+    )
+    for table, toml_name, setting_name in fields:
+        value = _value(table, toml_name)
+        if value is not None:
+            translated[setting_name] = value
+    return translated
+
+
+def write_gemini_activation(path: Path) -> None:
+    """Create a conservative non-secret config without replacing existing data."""
+    if path.exists():
+        raise LocalConfigError(
+            f"Lokale Konfiguration existiert bereits und wurde nicht überschrieben: {path}"
+        )
+    content = """# Javis local configuration. This file must never contain secrets.
+
+[providers]
+active = "auto"
+
+[providers.ollama]
+model = "qwen3:8b"
+base_url = "http://127.0.0.1:11434"
+timeout_seconds = 180
+
+[providers.gemini]
+enabled = true
+model = "gemini-3.6-flash"
+optional_model = "gemini-3.5-flash-lite"
+free_only = true
+billing_confirmed_disabled = true
+max_requests_per_day = 25
+max_input_chars = 12000
+max_output_tokens = 1024
+timeout_seconds = 30
+max_attempts = 2
+max_context_messages = 6
+"""
+    try:
+        path.parent.mkdir(parents=True, exist_ok=True)
+        temporary_path = path.with_suffix(path.suffix + ".tmp")
+        temporary_path.write_text(content, encoding="utf-8")
+        os.replace(temporary_path, path)
+    except OSError as exc:
+        raise LocalConfigError(
+            f"Lokale Konfiguration konnte nicht geschrieben werden: {path}"
+        ) from exc

src/javis/config/settings.py

@@ -8,6 +8,8 @@ from dataclasses import dataclass
 from pathlib import Path
 from urllib.parse import urlparse
 
+from javis.config.local_config import LocalConfigError, load_local_defaults
+
 
 class ConfigurationError(ValueError):
     """Raised when runtime configuration is unsafe or invalid."""
@@ -88,13 +90,35 @@ class Settings:
     def database_path(self) -> Path:
         return self.data_dir / "sessions.sqlite3"
 
+    @property
+    def usage_database_path(self) -> Path:
+        return self.data_dir / "provider-usage.sqlite3"
+
+    @property
+    def config_path(self) -> Path:
+        return self.data_dir / "javis.toml"
+
     @classmethod
     def from_env(cls, environ: Mapping[str, str] | None = None) -> Settings:
-        values = os.environ if environ is None else environ
-        configured_dir = values.get("JAVIS_DATA_DIR")
-        data_dir = Path(configured_dir).expanduser() if configured_dir else default_data_dir(values)
+        environment = os.environ if environ is None else environ
+        configured_dir = environment.get("JAVIS_DATA_DIR")
+        data_dir = (
+            Path(configured_dir).expanduser() if configured_dir else default_data_dir(environment)
+        )
         if not data_dir.is_absolute():
             raise ConfigurationError("JAVIS_DATA_DIR muss ein absoluter Pfad sein.")
+        data_dir = data_dir.resolve()
+
+        configured_file = environment.get("JAVIS_CONFIG_FILE")
+        config_path = (
+            Path(configured_file).expanduser() if configured_file else data_dir / "javis.toml"
+        )
+        if not config_path.is_absolute():
+            raise ConfigurationError("JAVIS_CONFIG_FILE muss ein absoluter Pfad sein.")
+        try:
+            values = {**load_local_defaults(config_path.resolve()), **environment}
+        except LocalConfigError as exc:
+            raise ConfigurationError(str(exc)) from exc
 
         provider = values.get("JAVIS_PROVIDER", "ollama").strip()
         model = values.get("JAVIS_MODEL", "qwen3:8b").strip()
@@ -116,7 +140,7 @@ class Settings:
             raise ConfigurationError("JAVIS_GEMINI_TIMEOUT muss eine Zahl sein.") from exc
 
         settings = cls(
-            data_dir=data_dir.resolve(),
+            data_dir=data_dir,
             provider=provider,
             model=model,
             ollama_base_url=base_url,