# -*- coding: utf-8 -*-
"""腾讯云 OCR 适配层 — 封装通用票据识别 & 通用文字识别"""
import base64
import logging

_logger = logging.getLogger(__name__)

# tencentcloud-sdk-python 为可选依赖，导入失败时给出明确提示
try:
    from tencentcloud.common import credential
    from tencentcloud.common.exception.tencent_cloud_sdk_exception import TencentCloudSDKException
    from tencentcloud.ocr.v20181119 import ocr_client, models
    HAS_TENCENT_SDK = True
except ImportError:
    HAS_TENCENT_SDK = False
    _logger.warning(
        'yuthon_ai_agent: tencentcloud-sdk-python 未安装，OCR 功能不可用。'
        '请执行: pip install tencentcloud-sdk-python'
    )

# 支持的图片 MIME 类型
SUPPORTED_IMAGE_TYPES = {
    'image/png', 'image/jpeg', 'image/jpg', 'image/bmp', 'image/gif',
}
SUPPORTED_PDF_TYPE = 'application/pdf'
MAX_IMAGE_SIZE = 10 * 1024 * 1024  # 10MB


class TencentOCR:
    """腾讯云 OCR 适配器"""

    def __init__(self, secret_id, secret_key, region='ap-guangzhou'):
        if not HAS_TENCENT_SDK:
            raise RuntimeError(
                'tencentcloud-sdk-python 未安装，请执行: pip install tencentcloud-sdk-python'
            )
        if not secret_id or not secret_key:
            raise ValueError('OCR SecretId / SecretKey 未配置')
        self.cred = credential.Credential(secret_id, secret_key)
        self.region = region
        self._client = None

    @property
    def client(self):
        if self._client is None:
            self._client = ocr_client.OcrClient(self.cred, self.region)
        return self._client

    def _encode_image(self, raw_bytes):
        """将图片/PDF 二进制数据转为 Base64 字符串"""
        return base64.b64encode(raw_bytes).decode('utf-8')

    def _validate_input(self, raw_bytes, mimetype):
        """校验输入大小 & 格式"""
        if len(raw_bytes) > MAX_IMAGE_SIZE:
            raise ValueError(f'文件大小超过限制（最大 10MB），当前 {len(raw_bytes) / 1024 / 1024:.1f}MB')
        if mimetype not in SUPPORTED_IMAGE_TYPES and mimetype != SUPPORTED_PDF_TYPE:
            raise ValueError(f'不支持的文件格式：{mimetype}，仅支持 PNG/JPG/BMP/GIF/PDF')

    def recognize_general(self, raw_bytes, mimetype='image/png'):
        """通用文字识别 — 适用于任意图片/PDF 的文字提取。

        :param raw_bytes: 文件二进制数据
        :param mimetype: MIME 类型
        :return: dict {success, text, error}
        """
        self._validate_input(raw_bytes, mimetype)
        try:
            image_base64 = self._encode_image(raw_bytes)
            req = models.GeneralBasicOCRRequest()
            req.ImageBase64 = image_base64
            # PDF 需要额外参数
            if mimetype == SUPPORTED_PDF_TYPE:
                req.IsPdf = True

            resp = self.client.GeneralBasicOCR(req)
            texts = []
            for item in resp.TextDetections:
                texts.append(item.DetectedText)
            return {
                'success': True,
                'text': '\n'.join(texts),
            }
        except TencentCloudSDKException as e:
            _logger.exception('Tencent OCR GeneralBasicOCR 调用失败')
            return {'success': False, 'error': f'OCR 识别失败：{e.message}'}
        except Exception as e:
            _logger.exception('OCR GeneralBasicOCR 异常')
            return {'success': False, 'error': f'OCR 异常：{str(e)}'}

    def recognize_invoice(self, raw_bytes, mimetype='image/png'):
        """通用票据识别（高级版）— 自动识别增值税发票、火车票、机票等。

        :param raw_bytes: 文件二进制数据
        :param mimetype: MIME 类型
        :return: dict {success, text, error}
        """
        self._validate_input(raw_bytes, mimetype)
        try:
            image_base64 = self._encode_image(raw_bytes)
            req = models.RecognizeGeneralInvoiceRequest()
            req.ImageBase64 = image_base64
            if mimetype == SUPPORTED_PDF_TYPE:
                req.IsPdf = True

            resp = self.client.RecognizeGeneralInvoice(req)
            items = resp.MixedInvoiceItems or []

            if not items:
                return {'success': True, 'text': '(未识别到票据信息)'}

            texts = []
            for item in items:
                item_type = getattr(item, 'Type', '未知票据')
                single_invoice = item.SingleInvoiceInfos
                if single_invoice:
                    texts.append(f'—— {item_type} ——')
                    for key, value in single_invoice.items():
                        if value:
                            texts.append(f'{key}：{value}')
            return {
                'success': True,
                'text': '\n'.join(texts) if texts else '(未识别到票据内容)',
            }
        except TencentCloudSDKException as e:
            _logger.exception('Tencent OCR RecognizeGeneralInvoice 调用失败')
            return {'success': False, 'error': f'OCR 识别失败：{e.message}'}
        except Exception as e:
            _logger.exception('OCR RecognizeGeneralInvoice 异常')
            return {'success': False, 'error': f'OCR 异常：{str(e)}'}

    def smart_recognize(self, raw_bytes, mimetype='image/png'):
        """智能识别：先尝试票据识别，失败则回退到通用文字识别。

        :return: dict {success, text, error}
        """
        # 先尝试票据识别
        result = self.recognize_invoice(raw_bytes, mimetype)
        if result['success'] and result.get('text') and '(未识别到票据' not in result['text']:
            return result
        # 回退到通用文字
        return self.recognize_general(raw_bytes, mimetype)


def get_ocr_instance(provider):
    """从 AiProvider 记录中创建 OCR 实例。

    :param provider: ai.provider 记录
    :return: (TencentOCR 实例 | None, str 错误原因)
    """
    if not provider.ocr_enabled:
        return None, 'OCR 未启用'

    # 逐项校验，给出精确的错误信息
    if not provider.ocr_secret_id:
        return None, '未配置 SecretId（请到服务商配置 → OCR配置 填写）'
    if not provider.ocr_secret_key:
        return None, '未配置 SecretKey（请到服务商配置 → OCR配置 填写）'
    if not HAS_TENCENT_SDK:
        return None, 'tencentcloud-sdk-python 未安装（pip install tencentcloud-sdk-python）'

    try:
        return TencentOCR(
            secret_id=provider.ocr_secret_id,
            secret_key=provider.ocr_secret_key,
            region=provider.ocr_region or 'ap-guangzhou',
        ), ''
    except ValueError as ve:
        _logger.warning('[AI-OCR] 参数错误: %s', ve)
        return None, str(ve)
    except Exception as e:
        _logger.exception('[AI-OCR] 创建 OCR 实例异常')
        return None, f'初始化异常: {e}'