# -*- coding: utf-8 -*-
"""JSONC（JSON with Comments）加载。

选择**自研轻量剥离**而非引入第三方依赖：本仓库运行依赖目前只有 ``httpx``，
配置加载属于启动/热更新热路径，JSONC 只需注释与尾逗号。实现按字符扫描，
在字符串字面量内保留 ``//``、``/*``、引号转义，避免误伤。

支持：
- ``//`` 行注释、``/* ... */`` 块注释
- 对象/数组中的尾逗号
- UTF-8 BOM
不支持 JSON5 扩展（无引号键、单引号、十六进制、``Infinity`` 等）。
"""

from __future__ import annotations

import json
from typing import Any


def strip_jsonc(text: str) -> str:
    """去掉 JSONC 注释与尾逗号，返回可交给 ``json.loads`` 的文本。"""
    if text.startswith("\ufeff"):
        text = text[1:]
    out: list[str] = []
    i = 0
    n = len(text)
    in_string = False
    escape = False
    while i < n:
        ch = text[i]
        if in_string:
            out.append(ch)
            if escape:
                escape = False
            elif ch == "\\":
                escape = True
            elif ch == '"':
                in_string = False
            i += 1
            continue
        if ch == '"':
            in_string = True
            out.append(ch)
            i += 1
            continue
        if ch == "/" and i + 1 < n:
            nxt = text[i + 1]
            if nxt == "/":
                i += 2
                while i < n and text[i] not in "\r\n":
                    i += 1
                continue
            if nxt == "*":
                i += 2
                while i + 1 < n and not (text[i] == "*" and text[i + 1] == "/"):
                    i += 1
                i = min(i + 2, n)
                continue
        out.append(ch)
        i += 1

    stripped = "".join(out)
    # 去掉尾逗号：`,}` / `,]`（可夹空白）
    cleaned: list[str] = []
    i = 0
    m = len(stripped)
    in_string = False
    escape = False
    while i < m:
        ch = stripped[i]
        if in_string:
            cleaned.append(ch)
            if escape:
                escape = False
            elif ch == "\\":
                escape = True
            elif ch == '"':
                in_string = False
            i += 1
            continue
        if ch == '"':
            in_string = True
            cleaned.append(ch)
            i += 1
            continue
        if ch == ",":
            j = i + 1
            while j < m and stripped[j] in " \t\r\n":
                j += 1
            if j < m and stripped[j] in "}]":
                i += 1
                continue
        cleaned.append(ch)
        i += 1
    return "".join(cleaned)


def loads(text: str) -> Any:
    """解析 JSONC 文本。"""
    return json.loads(strip_jsonc(text))


def load(path: str | bytes, *, encoding: str = "utf-8") -> Any:
    """从路径读取并解析 JSONC / JSON。"""
    with open(path, encoding=encoding) as fh:
        return loads(fh.read())