import os
from pathlib import Path
from typing import Final
from urllib.parse import urlsplit, urlunsplit

from dotenv import load_dotenv

BACKEND_ROOT: Final[Path] = Path(__file__).resolve().parents[1]
PROJECT_ROOT: Final[Path] = BACKEND_ROOT.parent

# Load env files from nearest to broadest scope.
# Priority (high -> low, with override=False preserving existing values):
# 1) process environment
# 2) backend/.env
# 3) project/.env
# 4) backend/.env.prod
# 5) project/.env.prod
load_dotenv(BACKEND_ROOT / ".env", override=False)
load_dotenv(PROJECT_ROOT / ".env.prod", override=False)


def _env_text(name: str, default: str) -> str:
    raw = os.getenv(name)
    if raw is None:
        return default
    return str(raw).replace("\\n", "\n")


def _env_bool(name: str, default: bool) -> bool:
    raw = os.getenv(name)
    if raw is None:
        return default
    return str(raw).strip().lower() in {"1", "true", "yes", "on"}


def _env_int(name: str, default: int, min_value: int, max_value: int) -> int:
    raw = os.getenv(name)
    if raw is None:
        return default
    try:
        value = int(str(raw).strip())
    except Exception:
        value = default
    return max(min_value, min(max_value, value))


def _normalize_dir_path(path_value: str) -> str:
    raw = str(path_value or "").strip()
    if not raw:
        return raw
    raw = os.path.expandvars(os.path.expanduser(raw))
    p = Path(raw)
    if p.is_absolute():
        return str(p)
    return str((BACKEND_ROOT / p).resolve())


DATA_ROOT: Final[str] = _normalize_dir_path(os.getenv("DATA_ROOT", str(PROJECT_ROOT / "data")))
BOTS_WORKSPACE_ROOT: Final[str] = _normalize_dir_path(
    os.getenv("BOTS_WORKSPACE_ROOT", str(PROJECT_ROOT / "workspace" / "bots"))
)


def _normalize_database_url(url: str) -> str:
    raw = str(url or "").strip()
    prefix = "sqlite:///"
    if not raw.startswith(prefix):
        return raw
    path_part = raw[len(prefix) :]
    if not path_part or path_part.startswith("/"):
        return raw
    abs_path = (BACKEND_ROOT / path_part).resolve()
    return f"{prefix}{abs_path.as_posix()}"


def _database_engine(url: str) -> str:
    raw = str(url or "").strip().lower()
    if raw.startswith("sqlite"):
        return "sqlite"
    if raw.startswith("postgresql"):
        return "postgresql"
    if raw.startswith("mysql"):
        return "mysql"
    if "+" in raw:
        return raw.split("+", 1)[0]
    if "://" in raw:
        return raw.split("://", 1)[0]
    return "unknown"


def _mask_database_url(url: str) -> str:
    raw = str(url or "").strip()
    if not raw or raw.startswith("sqlite"):
        return raw
    try:
        parsed = urlsplit(raw)
        if parsed.password is None:
            return raw
        host = parsed.hostname or ""
        if parsed.port:
            host = f"{host}:{parsed.port}"
        auth = parsed.username or ""
        if auth:
            auth = f"{auth}:***@{host}"
        else:
            auth = host
        netloc = auth
        return urlunsplit((parsed.scheme, netloc, parsed.path, parsed.query, parsed.fragment))
    except Exception:
        return raw


_db_env = str(os.getenv("DATABASE_URL") or "").strip()
DATABASE_URL: Final[str] = _normalize_database_url(
    _db_env if _db_env else f"sqlite:///{Path(DATA_ROOT) / 'nanobot_dashboard.db'}"
)
DATABASE_ENGINE: Final[str] = _database_engine(DATABASE_URL)
DATABASE_URL_DISPLAY: Final[str] = _mask_database_url(DATABASE_URL)
DATABASE_ECHO: Final[bool] = _env_bool("DATABASE_ECHO", True)
UPLOAD_MAX_MB: Final[int] = _env_int("UPLOAD_MAX_MB", 100, 1, 2048)
STT_ENABLED: Final[bool] = _env_bool("STT_ENABLED", True)
STT_MODEL: Final[str] = str(os.getenv("STT_MODEL") or "ggml-small-q8_0.bin").strip()
_DEFAULT_STT_MODEL_DIR: Final[Path] = (Path(DATA_ROOT) / "model").resolve()
_configured_stt_model_dir = _normalize_dir_path(os.getenv("STT_MODEL_DIR", str(_DEFAULT_STT_MODEL_DIR)))
if _configured_stt_model_dir and not Path(_configured_stt_model_dir).exists() and _DEFAULT_STT_MODEL_DIR.exists():
    STT_MODEL_DIR: Final[str] = str(_DEFAULT_STT_MODEL_DIR)
else:
    STT_MODEL_DIR: Final[str] = _configured_stt_model_dir
STT_DEVICE: Final[str] = str(os.getenv("STT_DEVICE") or "cpu").strip().lower() or "cpu"
STT_MAX_AUDIO_SECONDS: Final[int] = _env_int("STT_MAX_AUDIO_SECONDS", 20, 5, 600)
STT_DEFAULT_LANGUAGE: Final[str] = str(os.getenv("STT_DEFAULT_LANGUAGE") or "zh").strip().lower() or "zh"
STT_FORCE_SIMPLIFIED: Final[bool] = _env_bool("STT_FORCE_SIMPLIFIED", True)
STT_AUDIO_PREPROCESS: Final[bool] = _env_bool("STT_AUDIO_PREPROCESS", True)
STT_AUDIO_FILTER: Final[str] = str(
    os.getenv("STT_AUDIO_FILTER") or "highpass=f=120,lowpass=f=7600,afftdn=nf=-20"
).strip()
STT_INITIAL_PROMPT: Final[str] = str(
    os.getenv("STT_INITIAL_PROMPT")
    or "以下内容可能包含简体中文和英文术语。请优先输出简体中文，英文单词、缩写、品牌名和数字保持原文，不要翻译。"
).strip()

REDIS_ENABLED: Final[bool] = _env_bool("REDIS_ENABLED", False)
REDIS_URL: Final[str] = str(os.getenv("REDIS_URL") or "").strip()
REDIS_PREFIX: Final[str] = str(os.getenv("REDIS_PREFIX") or "dashboard_nanobot").strip() or "dashboard_nanobot"
REDIS_DEFAULT_TTL: Final[int] = _env_int("REDIS_DEFAULT_TTL", 60, 1, 86400)
PANEL_ACCESS_PASSWORD: Final[str] = str(os.getenv("PANEL_ACCESS_PASSWORD") or "").strip()

DEFAULT_AGENTS_MD: Final[str] = _env_text(
    "DEFAULT_AGENTS_MD",
    "# Agent Instructions\n\n- 优先完成任务目标\n- 操作前先说明意图\n- 输出必须可执行\n\n## 默认输出规范\n\n- 每次执行任务时，在 workspace 中创建新目录保存本次输出。\n- 输出内容默认采用 Markdown（.md）格式。",
).strip()

DEFAULT_SOUL_MD: Final[str] = _env_text(
    "DEFAULT_SOUL_MD",
    "# Soul\n\n你是专业的企业数字员工，表达清晰、可执行。",
).strip()

DEFAULT_USER_MD: Final[str] = _env_text(
    "DEFAULT_USER_MD",
    "# User\n\n- 语言: 中文\n- 风格: 专业\n- 偏好: 简明且有步骤",
).strip()

DEFAULT_TOOLS_MD: Final[str] = _env_text(
    "DEFAULT_TOOLS_MD",
    "# Tools\n\n- 谨慎使用 shell\n- 修改文件后复核\n- 失败时说明原因并重试策略",
).strip()

DEFAULT_IDENTITY_MD: Final[str] = _env_text(
    "DEFAULT_IDENTITY_MD",
    "# Identity\n\n- 角色: 企业数字员工\n- 领域: 运维与任务执行",
).strip()