package com.tcm.training.admin.system.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.tcm.training.admin.common.PageResponse;
import com.tcm.training.admin.system.dto.AppVersionCreateRequest;
import com.tcm.training.admin.system.entity.AppVersionConfig;
import com.tcm.training.admin.system.mapper.AppVersionConfigMapper;
import com.tcm.training.admin.system.vo.AppVersionCheckVO;
import com.tcm.training.admin.system.vo.AppVersionDetailVO;
import com.tcm.training.admin.system.vo.AppVersionListItemVO;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.ArrayList;
import java.util.List;

@Service
public class AppVersionSettingsAppService {

    private final AppVersionConfigMapper appVersionConfigMapper;

    public AppVersionSettingsAppService(AppVersionConfigMapper appVersionConfigMapper) {
        this.appVersionConfigMapper = appVersionConfigMapper;
    }

    public PageResponse<AppVersionListItemVO> page(int page, int pageSize) {
        LambdaQueryWrapper<AppVersionConfig> qw = new LambdaQueryWrapper<AppVersionConfig>()
                .eq(AppVersionConfig::getDeleted, 0)
                .orderByDesc(AppVersionConfig::getVersionCode)
                .orderByDesc(AppVersionConfig::getId);
        IPage<AppVersionConfig> result = appVersionConfigMapper.selectPage(new Page<AppVersionConfig>(page, pageSize), qw);
        List<AppVersionListItemVO> list = new ArrayList<AppVersionListItemVO>();
        for (AppVersionConfig item : result.getRecords()) {
            list.add(toListItem(item));
        }
        return PageResponse.of(list, result.getTotal(), result.getCurrent(), result.getSize());
    }

    public AppVersionDetailVO detail(Long id) {
        return toDetailVO(requireItem(id));
    }

    @Transactional(rollbackFor = Exception.class)
    public AppVersionDetailVO create(AppVersionCreateRequest request) {
        AppVersionConfig latest = latest();
        String androidFileUrl = normalizeOptionalText(request.getAndroidFileUrl());
        String androidFileName = normalizeOptionalText(request.getAndroidFileName());
        String iosFileUrl = normalizeOptionalText(request.getIosFileUrl());
        String iosFileName = normalizeOptionalText(request.getIosFileName());
        validatePackageFields(androidFileUrl, androidFileName, iosFileUrl, iosFileName);
        AppVersionConfig item = new AppVersionConfig();
        item.setVersionNo(request.getVersionNo().trim());
        item.setVersionCode(latest == null ? 1 : defaultNumber(latest.getVersionCode()) + 1);
        item.setAndroidFileUrl(androidFileUrl);
        item.setAndroidFileName(androidFileName);
        item.setIosFileUrl(iosFileUrl);
        item.setIosFileName(iosFileName);
        item.setForceUpdate(booleanToInteger(request.getForceUpdate()));
        item.setUpdateNotice(request.getUpdateNotice().trim());
        item.setDeleted(0);
        appVersionConfigMapper.insert(item);
        return toDetailVO(item);
    }

    public AppVersionCheckVO checkUpdate(String platform, Integer currentVersionCode) {
        return checkUpdate(platform, currentVersionCode, null);
    }

    public AppVersionCheckVO checkUpdate(String platform, Integer currentVersionCode, String currentVersionNo) {
        if (currentVersionCode == null) {
            throw new IllegalArgumentException("当前版本号不能为空");
        }
        if (currentVersionCode < 0) {
            throw new IllegalArgumentException("当前版本号不能小于0");
        }
        String normalizedPlatform = normalizePlatform(platform);
        AppVersionConfig latest = latest();
        AppVersionCheckVO vo = new AppVersionCheckVO();
        if (latest == null) {
            vo.setHasUpdate(Boolean.FALSE);
            return vo;
        }

        String downloadUrl = AppVersionConfig.PLATFORM_ANDROID.equals(normalizedPlatform)
                ? normalizeOptionalText(latest.getAndroidFileUrl())
                : normalizeOptionalText(latest.getIosFileUrl());
        boolean hasUpdate = downloadUrl != null && isNewerVersion(latest, currentVersionCode, currentVersionNo);
        vo.setHasUpdate(hasUpdate);
        if (!hasUpdate) {
            return vo;
        }
        vo.setLatestVersionNo(latest.getVersionNo());
        vo.setLatestVersionCode(defaultNumber(latest.getVersionCode()));
        vo.setForceUpdate(integerToBoolean(latest.getForceUpdate()));
        vo.setUpdateNotice(latest.getUpdateNotice());
        vo.setDownloadUrl(downloadUrl);
        return vo;
    }

    public AppVersionCheckVO checkUpdateNew(String platform) {

        String normalizedPlatform = normalizePlatform(platform);
        AppVersionConfig latest = latest();
        AppVersionCheckVO vo = new AppVersionCheckVO();
        if (latest == null) {
            vo.setHasUpdate(Boolean.FALSE);
            return vo;
        }

        String downloadUrl = AppVersionConfig.PLATFORM_ANDROID.equals(normalizedPlatform)
                ? normalizeOptionalText(latest.getAndroidFileUrl())
                : normalizeOptionalText(latest.getIosFileUrl());
        boolean hasUpdate = downloadUrl != null;
        vo.setHasUpdate(hasUpdate);
        if (!hasUpdate) {
            return vo;
        }
        vo.setLatestVersionNo(latest.getVersionNo());
        vo.setLatestVersionCode(defaultNumber(latest.getVersionCode()));
        vo.setForceUpdate(integerToBoolean(latest.getForceUpdate()));
        vo.setUpdateNotice(latest.getUpdateNotice());
        vo.setDownloadUrl(downloadUrl);
        return vo;
    }

    /**
     * 判断后台最新版本是否高于当前 APP，兼容原生 versionCode 与展示 versionNo 不一致的历史包。
     */
    private boolean isNewerVersion(AppVersionConfig latest, Integer currentVersionCode, String currentVersionNo) {
        if (defaultNumber(latest.getVersionCode()) > currentVersionCode) {
            return true;
        }
        return compareVersionNo(latest.getVersionNo(), currentVersionNo) > 0;
    }

    /**
     * 比较数字点号版本号，无法解析的版本号不参与兜底判断。
     */
    private int compareVersionNo(String latestVersionNo, String currentVersionNo) {
        String latest = normalizeOptionalText(latestVersionNo);
        String current = normalizeOptionalText(currentVersionNo);
        if (latest == null || current == null) {
            return 0;
        }
        String[] latestParts = latest.split("\\.");
        String[] currentParts = current.split("\\.");
        int maxLength = Math.max(latestParts.length, currentParts.length);
        for (int i = 0; i < maxLength; i++) {
            Integer latestNumber = parseVersionNumber(latestParts, i);
            Integer currentNumber = parseVersionNumber(currentParts, i);
            if (latestNumber == null || currentNumber == null) {
                return 0;
            }
            int compareResult = latestNumber.compareTo(currentNumber);
            if (compareResult != 0) {
                return compareResult;
            }
        }
        return 0;
    }

    /**
     * 解析指定版本号片段，缺失片段按 0 处理。
     */
    private Integer parseVersionNumber(String[] parts, int index) {
        if (index >= parts.length) {
            return 0;
        }
        String value = parts[index] == null ? "" : parts[index].trim();
        if (!value.matches("\\d+")) {
            return null;
        }
        try {
            return Integer.valueOf(value);
        } catch (NumberFormatException ex) {
            return null;
        }
    }

    private AppVersionConfig latest() {
        return appVersionConfigMapper.selectOne(new LambdaQueryWrapper<AppVersionConfig>()
                .eq(AppVersionConfig::getDeleted, 0)
                .orderByDesc(AppVersionConfig::getVersionCode)
                .orderByDesc(AppVersionConfig::getId)
                .last("limit 1"));
    }

    private AppVersionConfig requireItem(Long id) {
        AppVersionConfig item = appVersionConfigMapper.selectOne(new LambdaQueryWrapper<AppVersionConfig>()
                .eq(AppVersionConfig::getId, id)
                .eq(AppVersionConfig::getDeleted, 0)
                .last("limit 1"));
        if (item == null) {
            throw new IllegalArgumentException("APP版本不存在");
        }
        return item;
    }

    private String normalizePlatform(String platform) {
        if (platform == null) {
            throw new IllegalArgumentException("平台类型不能为空");
        }
        String normalized = platform.trim().toUpperCase();
        if (AppVersionConfig.PLATFORM_ANDROID.equals(normalized) || AppVersionConfig.PLATFORM_IOS.equals(normalized)) {
            return normalized;
        }
        throw new IllegalArgumentException("平台类型不合法");
    }

    private AppVersionListItemVO toListItem(AppVersionConfig item) {
        AppVersionListItemVO vo = new AppVersionListItemVO();
        vo.setId(item.getId());
        vo.setVersionNo(item.getVersionNo());
        vo.setUpdateNotice(item.getUpdateNotice());
        vo.setCreatedAt(item.getCreatedAt());
        return vo;
    }

    private AppVersionDetailVO toDetailVO(AppVersionConfig item) {
        AppVersionDetailVO vo = new AppVersionDetailVO();
        vo.setId(item.getId());
        vo.setVersionNo(item.getVersionNo());
        vo.setVersionCode(defaultNumber(item.getVersionCode()));
        vo.setAndroidFileUrl(item.getAndroidFileUrl());
        vo.setAndroidFileName(item.getAndroidFileName());
        vo.setIosFileUrl(item.getIosFileUrl());
        vo.setIosFileName(item.getIosFileName());
        vo.setForceUpdate(integerToBoolean(item.getForceUpdate()));
        vo.setUpdateNotice(item.getUpdateNotice());
        vo.setCreatedAt(item.getCreatedAt());
        return vo;
    }

    private Integer defaultNumber(Integer value) {
        return value == null ? 0 : value;
    }

    private Integer booleanToInteger(Boolean value) {
        return Boolean.TRUE.equals(value) ? 1 : 0;
    }

    private Boolean integerToBoolean(Integer value) {
        return value != null && value == 1;
    }

    private void validatePackageFields(String androidFileUrl, String androidFileName, String iosFileUrl, String iosFileName) {
        boolean hasAndroidFileUrl = androidFileUrl != null;
        boolean hasAndroidFileName = androidFileName != null;
        boolean hasIosFileUrl = iosFileUrl != null;
        boolean hasIosFileName = iosFileName != null;
        boolean hasAndroidPackage = hasAndroidFileUrl || hasAndroidFileName;
        boolean hasIosPackage = hasIosFileUrl || hasIosFileName;

        if (hasAndroidPackage && (!hasAndroidFileUrl || !hasAndroidFileName)) {
            throw new IllegalArgumentException("安卓文件地址和名称必须同时填写");
        }
        if (hasIosPackage && (!hasIosFileUrl || !hasIosFileName)) {
            throw new IllegalArgumentException("iOS文件地址和名称必须同时填写");
        }
        if (!hasAndroidPackage && !hasIosPackage) {
            throw new IllegalArgumentException("请至少上传一个安装包");
        }
    }

    private String normalizeOptionalText(String value) {
        if (value == null) {
            return null;
        }
        String trimmed = value.trim();
        return trimmed.isEmpty() ? null : trimmed;
    }
}