package vip.mate.skill.runtime;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import lombok.Builder;
import lombok.Data;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Service;
import vip.mate.skill.runtime.SkillFrontmatterParser.SkillDependencies;
import vip.mate.tool.ToolRegistry;
import vip.mate.tool.model.ToolEntity;
import vip.mate.tool.repository.ToolMapper;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import java.util.concurrent.TimeUnit;

/**
 * 技能依赖检查器
 * 检查 commands / env / tools / platforms 依赖是否满足
 */
@Slf4j
@Service
public class SkillDependencyChecker {

    private final ToolMapper toolMapper;
    private final ToolRegistry toolRegistry;

    /**
     * {@code @Lazy} on {@link ToolRegistry}: this bean is constructed during startup,
     * and ToolRegistry transitively depends on MCP / plugin infrastructure that also
     * runs early — the lazy proxy breaks that cycle.
     */
    public SkillDependencyChecker(ToolMapper toolMapper, @Lazy ToolRegistry toolRegistry) {
        this.toolMapper = toolMapper;
        this.toolRegistry = toolRegistry;
    }

    private static final String CURRENT_OS = detectOS();

    /**
     * 检查依赖
     */
    public DependencyCheckResult check(SkillDependencies dependencies, List<String> platforms, String skillName) {
        List<String> missing = new ArrayList<>();
        List<String> warnings = new ArrayList<>();
        boolean allSatisfied = true;

        // 1. 平台检查
        if (platforms != null && !platforms.isEmpty()) {
            boolean platformMatch = platforms.stream()
                .anyMatch(p -> p.equalsIgnoreCase(CURRENT_OS));
            if (!platformMatch) {
                missing.add("platform:" + CURRENT_OS + " (requires: " + String.join(", ", platforms) + ")");
                allSatisfied = false;
            }
        }

        if (dependencies == null || dependencies.isEmpty()) {
            return DependencyCheckResult.builder()
                .skillName(skillName)
                .satisfied(allSatisfied)
                .missing(missing)
                .warnings(warnings)
                .summary(allSatisfied ? "All dependencies satisfied" : buildSummary(missing))
                .build();
        }

        // 2. 命令检查
        for (String cmd : dependencies.getCommands()) {
            if (!isCommandAvailable(cmd)) {
                missing.add("command:" + cmd);
                allSatisfied = false;
            }
        }

        // 3. 环境变量检查
        for (String envVar : dependencies.getEnv()) {
            String value = System.getenv(envVar);
            if (value == null || value.isBlank()) {
                missing.add("env:" + envVar);
                allSatisfied = false;
            }
        }

        // 4. 内部工具检查 — fetch the runtime function-name set once per skill
        //    so we don't hit reflection N times when a skill lists many tools.
        Set<String> runtimeFunctionNames = dependencies.getTools().isEmpty()
                ? Set.of()
                : fetchRuntimeFunctionNames();
        for (String toolName : dependencies.getTools()) {
            if (!isToolAvailable(toolName, runtimeFunctionNames)) {
                missing.add("tool:" + toolName);
                allSatisfied = false;
            }
        }

        return DependencyCheckResult.builder()
            .skillName(skillName)
            .satisfied(allSatisfied)
            .missing(missing)
            .warnings(warnings)
            .summary(allSatisfied ? "All dependencies satisfied" : buildSummary(missing))
            .build();
    }

    // ==================== 检查方法 ====================

    private boolean isCommandAvailable(String command) {
        try {
            String checkCmd = isWindows() ? "where" : "which";
            ProcessBuilder pb = new ProcessBuilder(checkCmd, command);
            pb.redirectErrorStream(true);
            Process process = pb.start();

            // 快速消耗输出
            try (BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()))) {
                while (reader.readLine() != null) { /* drain */ }
            }

            boolean finished = process.waitFor(5, TimeUnit.SECONDS);
            if (!finished) {
                process.destroyForcibly();
                return false;
            }
            return process.exitValue() == 0;
        } catch (Exception e) {
            log.debug("Command check failed for '{}': {}", command, e.getMessage());
            return false;
        }
    }

    /**
     * The runtime registry (ToolRegistry) is authoritative: it knows the exact
     * function names LLMs and skills call by ({@code @Tool} method name / MCP
     * tool id / plugin tool name). The {@code mate_tool} DB overlay stores
     * class names + bean names and does NOT match that vocabulary, so checking
     * the DB alone mis-reports every real skill dependency as "missing".
     *
     * <p>We keep the DB lookup as a secondary fallback for the edge case where
     * someone has inserted a custom row whose {@code name} happens to equal the
     * function name.
     */
    private boolean isToolAvailable(String toolName, Set<String> runtimeFunctionNames) {
        if (runtimeFunctionNames.contains(toolName)) {
            return true;
        }
        try {
            Long count = toolMapper.selectCount(new LambdaQueryWrapper<ToolEntity>()
                .eq(ToolEntity::getName, toolName)
                .eq(ToolEntity::getEnabled, true));
            return count > 0;
        } catch (Exception e) {
            log.debug("Tool check failed for '{}': {}", toolName, e.getMessage());
            return false;
        }
    }

    private Set<String> fetchRuntimeFunctionNames() {
        try {
            return toolRegistry.availableFunctionNames();
        } catch (Exception e) {
            log.warn("Failed to fetch runtime tool function names, falling back to DB check only: {}",
                    e.getMessage());
            return Set.of();
        }
    }

    private static boolean isWindows() {
        return CURRENT_OS.equals("windows");
    }

    private static String detectOS() {
        String os = System.getProperty("os.name", "").toLowerCase(Locale.ROOT);
        if (os.contains("mac") || os.contains("darwin")) return "macos";
        if (os.contains("win")) return "windows";
        if (os.contains("linux")) return "linux";
        return os;
    }

    private String buildSummary(List<String> missing) {
        if (missing.isEmpty()) return "All dependencies satisfied";
        return "Missing: " + String.join(", ", missing);
    }

    // ==================== 结果模型 ====================

    @Data
    @Builder
    public static class DependencyCheckResult {
        private String skillName;
        private boolean satisfied;
        @Builder.Default
        private List<String> missing = new ArrayList<>();
        @Builder.Default
        private List<String> warnings = new ArrayList<>();
        private String summary;
    }
}