1 files changed, 167 insertions, 0 deletions
diff --git a/llamachat/config.py b/llamachat/config.py
new file mode 100644
index 0000000..fac72d5
--- /dev/null
+++ b/llamachat/config.py
@@ -0,0 +1,167 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# llamachat - a small native chat client for a local llama.cpp router
+# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+"""Config file loading and llama-server presets.ini parsing."""
+
+import configparser
+import os
+import tomllib
+from dataclasses import dataclass
+from pathlib import Path
+
+CONFIG_PATH = Path(
+    os.environ.get("XDG_CONFIG_HOME", Path.home() / ".config")
+) / "llamachat" / "config.toml"
+
+DEFAULTS = {
+    "base_url": "http://localhost:8181",
+    "presets": "/etc/llama-server/presets.ini",
+    "socket": "",  # empty -> $XDG_RUNTIME_DIR/llamachat.sock
+    "db": "",      # empty -> $XDG_DATA_HOME/llamachat/history.db
+    "default_model": "",
+    "request_timeout": 300,
+    # Fraction of a model's context we allow a single attachment to fill.
+    "attach_ctx_fraction": 0.5,
+    # Rough chars-per-token used to turn a ctx-size into a char budget.
+    "chars_per_token": 3.5,
+}
+
+
+@dataclass
+class Preset:
+    """One [section] of presets.ini, reduced to what the UI needs."""
+    name: str
+    vision: bool
+    ctx_size: int
+
+    def char_budget(self, fraction: float, chars_per_token: float) -> int:
+        return int(self.ctx_size * chars_per_token * fraction)
+
+
+@dataclass
+class Config:
+    base_url: str
+    presets_path: Path
+    socket_path: Path
+    db_path: Path
+    default_model: str
+    request_timeout: int
+    attach_ctx_fraction: float
+    chars_per_token: float
+
+
+def _runtime_dir() -> Path:
+    rd = os.environ.get("XDG_RUNTIME_DIR")
+    if rd:
+        return Path(rd)
+    # ponytail: /tmp fallback only matters on a broken session; no uid-dir
+    # creation dance, XDG_RUNTIME_DIR is set on any real Wayland login.
+    return Path("/tmp")
+
+
+def _data_dir() -> Path:
+    return Path(
+        os.environ.get("XDG_DATA_HOME", Path.home() / ".local" / "share")
+    ) / "llamachat"
+
+
+def load(path: Path = CONFIG_PATH) -> Config:
+    """Read config.toml, falling back to DEFAULTS for anything absent."""
+    values = dict(DEFAULTS)
+    if path.exists():
+        with open(path, "rb") as fh:
+            values.update(tomllib.load(fh))
+
+    socket = values["socket"] or (_runtime_dir() / "llamachat.sock")
+    db = values["db"] or (_data_dir() / "history.db")
+
+    return Config(
+        base_url=str(values["base_url"]).rstrip("/"),
+        presets_path=Path(values["presets"]).expanduser(),
+        socket_path=Path(str(socket)).expanduser(),
+        db_path=Path(str(db)).expanduser(),
+        default_model=str(values["default_model"]),
+        request_timeout=int(values["request_timeout"]),
+        attach_ctx_fraction=float(values["attach_ctx_fraction"]),
+        chars_per_token=float(values["chars_per_token"]),
+    )
+
+
+def write_default(path: Path = CONFIG_PATH) -> Path:
+    """Create a commented config.toml if none exists. Returns the path."""
+    if path.exists():
+        return path
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(
+        "# llamachat configuration\n"
+        f'base_url = "{DEFAULTS["base_url"]}"\n'
+        f'presets = "{DEFAULTS["presets"]}"\n'
+        '\n'
+        '# Leave empty for XDG defaults:\n'
+        '#   socket -> $XDG_RUNTIME_DIR/llamachat.sock\n'
+        '#   db     -> $XDG_DATA_HOME/llamachat/history.db\n'
+        'socket = ""\n'
+        'db = ""\n'
+        '\n'
+        '# Model selected at startup. Empty picks the first available.\n'
+        'default_model = ""\n'
+        '\n'
+        '# Seconds before a generation request is abandoned.\n'
+        f'request_timeout = {DEFAULTS["request_timeout"]}\n'
+        '\n'
+        '# How much of the model context one attachment may fill, and the\n'
+        '# chars-per-token estimate used to convert ctx-size into characters.\n'
+        f'attach_ctx_fraction = {DEFAULTS["attach_ctx_fraction"]}\n'
+        f'chars_per_token = {DEFAULTS["chars_per_token"]}\n'
+    )
+    return path
+
+
+def parse_presets(path: Path) -> dict[str, Preset]:
+    """Parse llama-server's presets.ini.
+
+    Both ';' and '#' start a comment there, so a commented-out `#mmproj`
+    line correctly reads as "this preset has no vision support".
+    """
+    parser = configparser.ConfigParser(
+        comment_prefixes=(";", "#"),
+        inline_comment_prefixes=(";", "#"),
+        strict=False,
+    )
+    try:
+        text = path.read_text(encoding="utf-8")
+    except OSError:
+        return {}
+
+    # presets.ini opens with a bare `version = 1` before any section, which
+    # configparser rejects. Give those leading keys a section to live in.
+    try:
+        parser.read_string("[__file__]\n" + text)
+    except configparser.Error:
+        return {}
+
+    presets: dict[str, Preset] = {}
+    for name in parser.sections():
+        if name == "__file__":
+            continue
+        section = parser[name]
+        try:
+            ctx = int(section.get("ctx-size", "4096"))
+        except ValueError:
+            ctx = 4096
+        presets[name] = Preset(
+            name=name,
+            vision=bool(section.get("mmproj", "").strip()),
+            ctx_size=ctx,
+        )
+    return presets