package com.sinata.appointment.integration;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.sinata.appointment.config.WechatOfficialAccountProperties;
import com.sinata.appointment.constants.BizErrorCode;
import com.sinata.appointment.exception.BizException;
import java.nio.charset.StandardCharsets;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponentsBuilder;
import org.springframework.web.util.UriUtils;

@Slf4j
@Service
@RequiredArgsConstructor
public class WechatOfficialAccountGateway {

    private static final String OAUTH_AUTHORIZE_URL =
            "https://open.weixin.qq.com/connect/oauth2/authorize";
    private static final String OAUTH_ACCESS_TOKEN_URL =
            "https://api.weixin.qq.com/sns/oauth2/access_token";

    private final WechatOfficialAccountProperties props;
    @Qualifier("wechatRestTemplate")
    private final RestTemplate restTemplate;
    private final ObjectMapper objectMapper;

    public String buildSilentOAuthUrl(String redirectUri, String state) {
        if (redirectUri == null || redirectUri.isBlank()) {
            throw new BizException(BizErrorCode.AUTH_INVALID_CREDENTIALS, "redirectUri 不能为空");
        }
        if (props.useStub()) {
            return UriComponentsBuilder.fromHttpUrl(redirectUri)
                    .queryParam("code", "STUB-" + System.currentTimeMillis())
                    .queryParam("state", state == null ? "" : state.trim())
                    .build()
                    .toUriString();
        }
        String encodedRedirect = UriUtils.encode(redirectUri, StandardCharsets.UTF_8);
        String safeState = state == null ? "" : state.trim();
        return OAUTH_AUTHORIZE_URL
                + "?appid=" + props.getAppId()
                + "&redirect_uri=" + encodedRedirect
                + "&response_type=code"
                + "&scope=snsapi_base"
                + "&state=" + UriUtils.encode(safeState, StandardCharsets.UTF_8)
                + "#wechat_redirect";
    }

    public WxOfficialOAuthResult exchangeCode(String code) {
        if (code == null || code.isBlank()) {
            throw new BizException(BizErrorCode.AUTH_INVALID_CREDENTIALS, "code 不能为空");
        }
        if (props.useStub()) {
            log.debug("Wechat official account stub: oauth code");
            return WxOfficialOAuthResult.stub(code);
        }
        String url = UriComponentsBuilder.fromHttpUrl(OAUTH_ACCESS_TOKEN_URL)
                .queryParam("appid", props.getAppId())
                .queryParam("secret", props.getAppSecret())
                .queryParam("code", code)
                .queryParam("grant_type", "authorization_code")
                .build()
                .toUriString();
        try {
            String body = restTemplate.getForObject(url, String.class);
            JsonNode root = objectMapper.readTree(body);
            int err = root.path("errcode").asInt(0);
            if (err != 0) {
                String msg = root.path("errmsg").asText("wx error");
                log.warn("official oauth errcode={} msg={}", err, msg);
                throw new BizException(BizErrorCode.MINI_WX_API_ERROR, "公众号授权失败: " + msg);
            }
            String openId = root.path("openid").asText(null);
            if (openId == null || openId.isBlank()) {
                throw new BizException(BizErrorCode.MINI_WX_API_ERROR, "公众号未返回 openid");
            }
            return WxOfficialOAuthResult.builder()
                    .openId(openId)
                    .unionId(root.path("unionid").asText(null))
                    .build();
        } catch (BizException e) {
            throw e;
        } catch (Exception e) {
            log.error("official oauth http error", e);
            throw new BizException(BizErrorCode.MINI_WX_API_ERROR, "公众号授权接口异常");
        }
    }
}