from __future__ import annotations

import os
from typing import Any

_ENV_VAR_MAP: dict[str, str] = {
    "MATRIX_HOMESERVER": "homeserver",
    "MATRIX_USER_ID": "user_id",
    "MATRIX_ACCESS_TOKEN": "access_token",
    "MATRIX_PASSWORD": "password",
    "MATRIX_DEVICE_ID": "device_id",
    "MATRIX_DEVICE_NAME": "deviceName",
    "MATRIX_CRYPTO_STORE_DIR": "crypto_store_dir",
    "MATRIX_DM_POLICY": "dm.policy",
    "MATRIX_GROUP_POLICY": "groupPolicy",
    "MATRIX_PROXY": "proxy",
    "MATRIX_AUTO_JOIN": "autoJoin",
    "MATRIX_SYNC_TIMEOUT_MS": "sync_timeout_ms",
    "MATRIX_DISPLAY_NAME": "display_name",
    "MATRIX_AVATAR_URL": "avatarUrl",
    "MATRIX_RESPONSE_PREFIX": "responsePrefix",
    "MATRIX_MEDIA_MAX_MB": "mediaMaxMb",
}

_NESTED_KEY_MAP: dict[str, tuple[str, str]] = {
    "dm.policy": ("dm", "policy"),
    "groupPolicy": (None, "groupPolicy"),
}


def resolve_env_vars(config: dict[str, Any], account_id: str = "") -> dict[str, Any]:
    result = dict(config)

    for env_var, config_key in _ENV_VAR_MAP.items():
        env_value = os.environ.get(env_var)
        if env_value is not None:
            if "." in config_key:
                _set_nested(result, config_key, env_value)
            else:
                result[config_key] = _coerce_type(env_value, config.get(config_key))

    if account_id:
        prefix = f"MATRIX_{account_id.upper()}_"
        for env_name, env_value in os.environ.items():
            if env_name.startswith(prefix):
                config_key = env_name[len(prefix) :].lower()
                result[config_key] = _coerce_type(env_value, config.get(config_key))

    return result


def _set_nested(config: dict[str, Any], key: str, value: Any) -> None:
    parts = key.split(".")
    if len(parts) == 2:
        parent, child = parts
        if parent not in config or not isinstance(config[parent], dict):
            config[parent] = {}
        config[parent][child] = value


def _coerce_type(value: str, existing: Any) -> Any:
    if existing is None:
        return value

    if isinstance(existing, bool):
        return value.lower() in ("true", "1", "yes")
    if isinstance(existing, int):
        try:
            return int(value)
        except ValueError:
            return value
    if isinstance(existing, float):
        try:
            return float(value)
        except ValueError:
            return value

    return value


def get_env_var_descriptions() -> dict[str, str]:
    return {
        "MATRIX_HOMESERVER": "Matrix homeserver URL (e.g. https://matrix.org)",
        "MATRIX_USER_ID": "Matrix user ID (e.g. @bot:matrix.org)",
        "MATRIX_ACCESS_TOKEN": "Matrix access token (alternative to password)",
        "MATRIX_PASSWORD": "Matrix account password",
        "MATRIX_DEVICE_ID": "Device ID for this session",
        "MATRIX_DEVICE_NAME": "Display name for this device",
        "MATRIX_CRYPTO_STORE_DIR": "Directory for E2EE key storage",
        "MATRIX_DM_POLICY": "DM access policy: open/disabled/allowlist/pairing",
        "MATRIX_GROUP_POLICY": "Group access policy: open/disabled/allowlist",
        "MATRIX_PROXY": "HTTP(S) proxy URL",
        "MATRIX_AUTO_JOIN": "Auto-join policy: off/always/allowlist/invites",
        "MATRIX_SYNC_TIMEOUT_MS": "Sync timeout in milliseconds",
        "MATRIX_DISPLAY_NAME": "Bot display name",
        "MATRIX_AVATAR_URL": "Bot avatar URL (mxc:// or https://)",
        "MATRIX_RESPONSE_PREFIX": "Prefix added to all bot responses",
        "MATRIX_MEDIA_MAX_MB": "Maximum media file size in MB",
    }