"""内置符文集合。

对齐酒馆核心子集（``char`` / ``user`` / ``original`` / ``random`` / ``roll`` /
``getvar``）+ 魂镜扩展（辰正时态宏，复用 ``time_sense.TemporalSnapshot``）。
全部为纯函数解析器，不做 IO 或代码执行。

注：酒馆的 ``pick``（不重复随机）与 ``setvar``（写变量）需要跨调用状态，
不在无状态渲染层实现；如需，由调用方在 ``MacroContext.variables`` 维护后注入。
"""

from __future__ import annotations

import random
import re

from app.modules.macros.engine import MacroRegistry, MacroResolver
from app.modules.macros.types import MacroContext


def _char(_args: list[str], ctx: MacroContext) -> str:
    return ctx.char_name or ""


def _user(_args: list[str], ctx: MacroContext) -> str:
    return ctx.user_name or ""


def _original(_args: list[str], ctx: MacroContext) -> str:
    return ctx.original or ""


def _random(args: list[str], _ctx: MacroContext) -> str:
    if not args:
        return ""
    return random.choice(args)


def _roll(args: list[str], _ctx: MacroContext) -> str:
    """``{{roll:NdM}}`` 或 ``{{roll:dM}}`` → N 个 M 面骰求和。非法规格原样返回。"""
    spec = (args[0] if args else "1d6").strip().casefold()
    match = re.fullmatch(r"(?P<n>\d*)d(?P<sides>\d+)", spec)
    if match is None:
        return spec
    count = int(match.group("n") or 1)
    sides = int(match.group("sides"))
    if count < 1 or sides < 1:
        return spec
    return str(sum(random.randint(1, sides) for _ in range(count)))


def _getvar(args: list[str], ctx: MacroContext) -> str:
    return ctx.variables.get(args[0], "") if args else ""


def _snapshot_field(field: str) -> MacroResolver:
    """从辰正快照取字段；快照未注入时返回空串。"""

    def _resolve(_args: list[str], ctx: MacroContext) -> str:
        snap = ctx.snapshot
        if snap is None:
            return ""
        value = getattr(snap, field, None)
        return "" if value is None else str(value)

    return _resolve


# 辰正时态宏名 → TemporalSnapshot 字段（魂镜扩展）
_TIME_MACROS: tuple[tuple[str, str], ...] = (
    ("date", "solar_date"),
    ("time", "local_time"),
    ("day_period", "day_period"),
    ("shichen", "shichen"),
    ("season", "season"),
    ("solar_term", "solar_term"),
    ("weekday", "weekday"),
)


def build_default_registry() -> MacroRegistry:
    """构造默认符文注册表。"""
    reg = MacroRegistry()
    reg.register("char", _char)
    reg.register("bot", _char)  # 酒馆别名
    reg.register("user", _user)
    reg.register("original", _original)
    reg.register("random", _random)
    reg.register("roll", _roll)
    reg.register("getvar", _getvar)
    for name, field in _TIME_MACROS:
        reg.register(name, _snapshot_field(field))
    return reg