from __future__ import annotations

import re

from yuxi.channel.protocols import SessionResolution

_RE_DIGITS = re.compile(r"^\d+$")


class ZaloSession:
    @staticmethod
    def build_conversation_id(chat_type: str, target_id: str) -> str:
        if chat_type == "GROUP":
            return f"zalo:group:{target_id}"
        return f"zalo:{target_id}"

    @staticmethod
    def build_session_key(agent_id: str, account_id: str, chat_type: str, target_id: str) -> str:
        chat = "direct" if chat_type in ("PRIVATE", "direct") else "group"
        return f"agent:{agent_id}:zalo:{chat}:{target_id}"

    @staticmethod
    def normalize_target(raw: str) -> str:
        target = raw.strip()
        for prefix in ("zalo:", "zl:"):
            if target.lower().startswith(prefix.lower()):
                target = target[len(prefix) :]
                break
        return target

    @staticmethod
    def parse_target(raw: str) -> tuple[str, str]:
        """Parse a target string into (chat_type, target_id).

        Supported formats:
        - zalo:{userId}         → ("direct", userId)
        - zl:{userId}           → ("direct", userId)
        - zalo:group:{chatId}   → ("group", chatId)
        - zl:group:{chatId}     → ("group", chatId)
        - {digits}              → ("direct", digits)
        """
        target = raw.strip()

        for prefix in ("zalo:", "zl:"):
            if target.lower().startswith(prefix.lower()):
                remainder = target[len(prefix) :]
                if remainder.lower().startswith("group:"):
                    return ("group", remainder[len("group:") :])
                return ("direct", remainder)

        if _RE_DIGITS.match(target):
            return ("direct", target)

        return ("direct", target)

    @staticmethod
    def resolve_dm_session(sender_id: str) -> SessionResolution:
        return SessionResolution(
            kind="direct",
            conversation_id=f"zalo:{sender_id}",
        )

    @staticmethod
    def resolve_group_session(chat_id: str) -> SessionResolution:
        return SessionResolution(
            kind="group",
            conversation_id=f"zalo:group:{chat_id}",
        )