"""
Redis client wrapper — duck-typed, lazy-imports redis module.
"""

from core.logger import log

_redis = None


def _get_redis():
    global _redis
    if _redis is None:
        import redis as _r
        _redis = _r
    return _redis


class RedisClient:
    """Manage a single Redis connection. No ABC — duck typing."""

    def __init__(self, server: dict):
        self._host = server["ip"]
        self._port = int(server.get("port", 6379))
        self._password = server.get("password") or None
        self._db = int(server.get("db_index", 0))
        self._conn = None

    # -- lifecycle --------------------------------------------------------

    def connect(self) -> bool:
        try:
            r = _get_redis()
            self._conn = r.Redis(
                host=self._host,
                port=self._port,
                password=self._password,
                db=self._db,
                decode_responses=True,
                socket_timeout=5,
                socket_connect_timeout=5,
            )
            self._conn.ping()
            log.info("Redis connected %s:%s db=%s", self._host, self._port, self._db)
            return True
        except Exception as exc:
            log.error("Redis connect failed: %s", exc)
            self._conn = None
            return False

    def disconnect(self):
        if self._conn is not None:
            try:
                self._conn.close()
            except Exception:
                pass
            self._conn = None
            log.info("Redis disconnected")

    def check_connection(self) -> bool:
        try:
            return self._conn is not None and self._conn.ping()
        except Exception:
            return False

    # -- commands ---------------------------------------------------------

    def execute(self, command: str) -> str:
        """Parse a raw command string, execute via redis-py, return formatted."""
        if not self._conn:
            return "[not connected]"
        parts = command.split()
        if not parts:
            return ""
        try:
            result = self._conn.execute_command(*parts)
            return self._format(result)
        except Exception as exc:
            return f"(error) {exc}"

    def info(self, section=None) -> dict:
        if not self._conn:
            return {}
        try:
            return self._conn.info(section) if section else self._conn.info()
        except Exception as exc:
            log.error("Redis INFO failed: %s", exc)
            return {}

    def dbsize(self) -> int:
        if not self._conn:
            return 0
        try:
            return self._conn.dbsize()
        except Exception as exc:
            log.error("Redis DBSIZE failed: %s", exc)
            return 0

    def keys(self, pattern: str = "*", count: int = 100) -> list[str]:
        """Return up to *count* keys matching *pattern* via SCAN."""
        if not self._conn:
            return []
        result = []
        try:
            cursor = 0
            while len(result) < count:
                cursor, batch = self._conn.scan(cursor, match=pattern, count=count)
                result.extend(batch)
                if cursor == 0:
                    break
            return result[:count]
        except Exception as exc:
            log.error("Redis SCAN failed: %s", exc)
            return []

    def get_type(self, key: str) -> str:
        if not self._conn:
            return "none"
        try:
            return self._conn.type(key)
        except Exception:
            return "none"

    def get_ttl(self, key: str) -> int:
        """Return TTL in seconds (-1 no expiry, -2 key missing)."""
        if not self._conn:
            return -2
        try:
            return self._conn.ttl(key)
        except Exception:
            return -2

    def get_value(self, key: str) -> str:
        """Auto-detect type and return a human-readable string."""
        if not self._conn:
            return "(not connected)"
        try:
            t = self.get_type(key)
            if t == "string":
                return self._conn.get(key) or ""
            if t == "list":
                items = self._conn.lrange(key, 0, 99)
                return "\n".join(f"{i}) {v}" for i, v in enumerate(items))
            if t == "set":
                items = list(self._conn.sscan_iter(key, count=100))[:100]
                return "\n".join(items)
            if t == "hash":
                data = self._conn.hgetall(key)
                return "\n".join(f"{k} -> {v}" for k, v in data.items())
            if t == "zset":
                items = self._conn.zrange(key, 0, 99, withscores=True)
                return "\n".join(f"{v} (score={s})" for v, s in items)
            return f"(unknown type: {t})"
        except Exception as exc:
            return f"(error) {exc}"

    # -- helpers ----------------------------------------------------------

    @staticmethod
    def _format(value) -> str:
        if value is None:
            return "(nil)"
        if isinstance(value, bool):
            return "OK" if value else "(error)"
        if isinstance(value, int):
            return f"(integer) {value}"
        if isinstance(value, (list, tuple)):
            if not value:
                return "(empty list)"
            lines = [f"{i + 1}) {RedisClient._format(v)}" for i, v in enumerate(value)]
            return "\n".join(lines)
        return str(value)