"""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