import re
import logging

logger = logging.getLogger(__name__)

USER_ID_PATTERN = re.compile(r'^[a-zA-Z0-9]+$')


def validate_user_id(user_id):
    if not user_id:
        return False, "人员ID不能为空"
    if not USER_ID_PATTERN.match(user_id):
        return False, "人员ID仅支持大小写英文字母和数字"
    if len(user_id) > 50:
        return False, "人员ID长度不能超过50"
    return True, ""


def validate_user_name(user_name):
    if not user_name:
        return False, "人员姓名不能为空"
    if len(user_name) > 100:
        return False, "人员姓名长度不能超过100"
    return True, ""


def validate_height(height):
    if height is None or height == "":
        return True, None
    try:
        h = float(height)
        if 0.1 <= h <= 10.0:
            return True, round(h, 1)
        return False, f"高度 {height} 超出有效范围 0.1~10.0"
    except (ValueError, TypeError):
        return False, f"高度 {height} 不是有效数值"


def validate_noise_level(level):
    if level is None or level == "":
        return True, 0
    try:
        n = int(level)
        if 0 <= n <= 10:
            return True, n
        return False, f"噪声强度 {level} 超出有效范围 0~10"
    except (ValueError, TypeError):
        return False, f"噪声强度 {level} 不是有效整数"


def validate_rotate(min_val, max_val):
    def _clamp(v):
        try:
            v = int(v)
            return max(-180, min(180, v))
        except (ValueError, TypeError):
            return 0
    r_min = _clamp(min_val) if min_val not in (None, "") else 0
    r_max = _clamp(max_val) if max_val not in (None, "") else 0
    return True, (r_min, r_max)


def validate_match_mode(mode):
    if mode in ('upload', 'id', 'name', 'auto'):
        return True, ""
    return False, f"匹配模式 '{mode}' 无效，支持: upload/id/name/auto"


def validate_docx_name(name):
    if not name:
        return False, "文件名不能为空"
    if not name.lower().endswith('.docx'):
        return False, "仅支持.docx格式"
    return True, ""


def validate_docx_size(data_bytes, max_bytes):
    if not isinstance(data_bytes, (bytes, bytearray)):
        return False, "文档数据无效"
    if len(data_bytes) > max_bytes:
        return False, f"文档大小 {len(data_bytes)} 字节超过限制 {max_bytes} 字节"
    return True, ""


def validate_image_size(data_bytes, max_bytes):
    if not isinstance(data_bytes, (bytes, bytearray)):
        return False, "图片数据无效"
    if len(data_bytes) > max_bytes:
        return False, f"图片大小 {len(data_bytes)} 字节超过限制 {max_bytes} 字节"
    return True, ""


def validate_capture_group(group):
    if group is None or group == "":
        return False, "捕获组序号不能为空"
    try:
        g = int(group)
    except (ValueError, TypeError):
        return False, f"捕获组序号 '{group}' 不是整数"
    if g < 1:
        return False, "捕获组序号禁止为 0 或负数，必须 >=1"
    return True, g


def validate_rule(rule):
    errors = []
    if not rule.get('name'):
        errors.append("规则名称不能为空")
    pattern = rule.get('pattern')
    if not pattern:
        errors.append("规则正则表达式不能为空")
    else:
        try:
            re.compile(pattern)
        except re.error as e:
            errors.append(f"正则表达式非法: {e}")
    valid, msg_or_val = validate_capture_group(rule.get('capture_group'))
    if not valid:
        errors.append(msg_or_val)
    cell_mode = rule.get('cell_mode', 'single')
    if cell_mode not in ('single', 'horizontal', 'vertical'):
        errors.append(f"表格方式 '{cell_mode}' 无效")
    cell_match = rule.get('cell_match', 'partial')
    if cell_match not in ('partial', 'whole'):
        errors.append(f"匹配方式 '{cell_match}' 无效")
    return errors


def validate_sign_request(params):
    errors = []

    valid, msg = validate_docx_name(params.get('docx_name', ''))
    if not valid:
        errors.append(msg)

    valid, msg = validate_match_mode(params.get('match_mode', ''))
    if not valid:
        errors.append(msg)

    stamps = params.get('stamps', [])
    if params.get('match_mode') != 'auto' and not stamps:
        errors.append("非auto模式必须提供盖章项列表")

    if len(stamps) > 100:
        errors.append("盖章项不能超过100个")

    height = params.get('height')
    if height is not None and height != "":
        valid, _ = validate_height(height)
        if not valid:
            errors.append(f"全局高度无效: {validate_height(height)[1]}")

    noise = params.get('noise_level')
    if noise is not None and noise != "":
        valid, _ = validate_noise_level(noise)
        if not valid:
            errors.append(f"全局噪声无效: {validate_noise_level(noise)[1]}")

    return errors