package com.xuqm.tenant.service;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;
import java.util.function.Consumer;

@Service
public class SystemUpdateService {

    private static final Logger log = LoggerFactory.getLogger(SystemUpdateService.class);

    private static final List<String> OTHER_SERVICES = List.of(
            "file-service", "tenant-web", "im-service", "push-service", "update-service", "license-service"
    );

    @Value("${PRIVATE_DEPLOY_ROOT:/opt/xuqm-private}")
    private String deployRoot;

    public void runUpdate(Consumer<String> emit) {
        String composeFile = deployRoot + "/docker-compose.yml";

        // Authenticate to the registry before pulling (credentials stored in .env by deploy.sh)
        dockerLogin(emit);

        emit.accept(">>> 拉取最新镜像...");
        for (String svc : OTHER_SERVICES) {
            if (isRunning(svc)) {
                emit.accept("  pulling " + svc + " ...");
                exec(emit, "docker", "compose", "-f", composeFile, "pull", "--quiet", svc);
            }
        }
        emit.accept("  pulling tenant-service ...");
        exec(emit, "docker", "compose", "-f", composeFile, "pull", "--quiet", "tenant-service");
        emit.accept(">>> 镜像拉取完成");

        emit.accept(">>> 重启各服务...");
        for (String svc : OTHER_SERVICES) {
            if (isRunning(svc)) {
                emit.accept("  restarting " + svc + " ...");
                exec(emit, "docker", "compose", "-f", composeFile,
                        "up", "-d", "--no-deps", "--force-recreate", svc);
                emit.accept("  " + svc + " ✓");
            }
        }

        // tenant-service 自身的重建：不能直接用 docker compose，因为一旦发出 stop 指令，
        // 当前容器（含 docker compose 进程）会立即被杀死，后续的 rm/create/start 步骤不会执行。
        // 解决方案：先用 docker run -d 启动一个独立助手容器，它不依附于 tenant-service，
        // 能在 tenant-service 停止后继续完成重建。
        emit.accept(">>> 启动自更新助手容器...");
        String selfImage = getCurrentImage();
        if (selfImage == null) {
            emit.accept(">>> [错误] 无法获取当前 tenant-service 镜像名，请检查容器标签或手动执行更新。");
            emit.accept("DONE");
            return;
        }
        boolean helperStarted = spawnSelfUpdater(composeFile, selfImage);

        if (helperStarted) {
            emit.accept(">>> 助手容器已就绪，tenant-service 即将重建（连接将短暂中断）...");
            emit.accept("RESTART_SELF");
        } else {
            emit.accept(">>> [警告] 助手容器启动失败，请手动执行：");
            emit.accept(">>>   docker compose -f " + composeFile + " up -d --no-deps --force-recreate tenant-service");
            emit.accept("DONE");
        }
    }

    /**
     * Read REGISTRY / REGISTRY_USER / REGISTRY_PASSWORD from deployRoot/.env and
     * run "docker login" so that subsequent pulls succeed on private registries.
     */
    private void dockerLogin(Consumer<String> emit) {
        try {
            String registry = null, user = null, password = null;
            for (String line : Files.readAllLines(Paths.get(deployRoot + "/.env"))) {
                if (line.startsWith("REGISTRY="))          registry = line.substring("REGISTRY=".length()).trim();
                else if (line.startsWith("REGISTRY_USER=")) user     = line.substring("REGISTRY_USER=".length()).trim();
                else if (line.startsWith("REGISTRY_PASSWORD=")) password = line.substring("REGISTRY_PASSWORD=".length()).trim();
            }
            if (registry == null || user == null || password == null || password.isEmpty()) return;
            // REGISTRY format: host/namespace  →  extract host
            String host = registry.contains("/") ? registry.substring(0, registry.indexOf('/')) : registry;
            ProcessBuilder pb = new ProcessBuilder("docker", "login", host, "-u", user, "--password-stdin")
                    .redirectErrorStream(true);
            Process p = pb.start();
            p.getOutputStream().write((password + "\n").getBytes());
            p.getOutputStream().flush();
            p.getOutputStream().close();
            String out = new String(p.getInputStream().readAllBytes()).trim();
            int code = p.waitFor();
            if (code == 0) {
                emit.accept("  已完成镜像仓库登录");
            } else {
                emit.accept("  [警告] 镜像仓库登录失败，将使用本地缓存（" + out + "）");
            }
        } catch (Exception e) {
            emit.accept("  [警告] 读取仓库凭据失败: " + e.getMessage());
        }
    }

    /**
     * 启动一个独立的 detached 容器，在 tenant-service 被停止后重建它。
     * 助手容器与 tenant-service 无父子关系，不会随 tenant-service 终止。
     */
    private boolean spawnSelfUpdater(String composeFile, String image) {
        try {
            // 清理上次残留（若有）
            new ProcessBuilder("docker", "rm", "-f", "xuqm-self-updater")
                    .redirectErrorStream(true).start().waitFor();

            // 等待 8 秒确保 tenant-service 已完全停止，然后执行 force-recreate
            String shellCmd = "sleep 8 && docker compose -f " + composeFile
                    + " up -d --no-deps --force-recreate tenant-service";

            Process p = new ProcessBuilder(
                    "docker", "run", "-d", "--rm",
                    "--name", "xuqm-self-updater",
                    "-v", "/var/run/docker.sock:/var/run/docker.sock",
                    "-v", deployRoot + ":" + deployRoot,
                    "--entrypoint", "sh",
                    image,
                    "-c", shellCmd
            ).redirectErrorStream(true).start();

            String out = new String(p.getInputStream().readAllBytes()).trim();
            int code = p.waitFor();
            log.info("self-updater spawn: code={} containerId={}", code, out);
            return code == 0;
        } catch (Exception e) {
            log.error("failed to spawn self-updater", e);
            return false;
        }
    }

    // Filter only by service label — avoids dependency on project name which varies by deploy root dir.
    private boolean isRunning(String service) {
        try {
            Process p = new ProcessBuilder(
                    "docker", "ps", "-q",
                    "--filter", "label=com.docker.compose.service=" + service
            ).redirectErrorStream(true).start();
            String out = new String(p.getInputStream().readAllBytes()).trim();
            p.waitFor();
            return !out.isEmpty();
        } catch (Exception e) {
            return false;
        }
    }

    private String getCurrentImage() {
        try {
            Process p = new ProcessBuilder(
                    "docker", "ps",
                    "--filter", "label=com.docker.compose.service=tenant-service",
                    "--format", "{{.Image}}"
            ).redirectErrorStream(true).start();
            String out = new String(p.getInputStream().readAllBytes()).trim();
            p.waitFor();
            return out.isEmpty() ? null : out;
        } catch (Exception e) {
            return null;
        }
    }

    private void exec(Consumer<String> emit, String... cmd) {
        try {
            Process p = new ProcessBuilder(cmd)
                    .redirectErrorStream(true)
                    .start();
            try (BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()))) {
                String line;
                while ((line = reader.readLine()) != null) {
                    if (!line.isBlank()) emit.accept("    " + line);
                }
            }
            int code = p.waitFor();
            if (code != 0) emit.accept("    [warn] exit code " + code);
        } catch (Exception e) {
            emit.accept("    [error] " + e.getMessage());
            log.error("exec failed: {}", String.join(" ", cmd), e);
        }
    }
}