package com.codechecker.cache.analyze;

import java.io.IOException;
import java.io.UncheckedIOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Stream;

/**
 * 扫描工作树中受包含/排除模块限制的 {@code src/main/java} 下的所有 Java 源文件。
 * <p>返回路径 → 源码内容映射，供 {@link SchemaCheckAnalyzer} 构建新旧 {@code SourceIndex}。</p>
 */
public class FileScanner {

    private final Path repoRoot;
    private final List<String> includeModules;
    private final List<String> excludeModules;

    public FileScanner(Path repoRoot, List<String> includeModules, List<String> excludeModules) {
        this.repoRoot = repoRoot;
        this.includeModules = includeModules;
        this.excludeModules = excludeModules;
    }

    /**
     * @return 相对仓库根（/ 分隔）-> 文件内容
     */
    public Map<String, String> scan() {
        Map<String, String> result = new LinkedHashMap<>();
        try (Stream<Path> stream = Files.walk(repoRoot)) {
            List<Path> javaFiles = stream
                    .filter(Files::isRegularFile)
                    .filter(p -> p.toString().endsWith(".java"))
                    .filter(p -> {
                        String rel = repoRoot.relativize(p).toString().replace('\\', '/');
                        return rel.contains("/src/main/java/") && moduleAllowed(rel);
                    })
                    .collect(java.util.stream.Collectors.toList());
            javaFiles.parallelStream().forEach(p -> {
                String rel = repoRoot.relativize(p).toString().replace('\\', '/');
                try {
                    synchronized (result) {
                        result.put(rel, new String(Files.readAllBytes(p), StandardCharsets.UTF_8));
                    }
                } catch (IOException e) {
                    throw new UncheckedIOException(e);
                }
            });
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
        return result;
    }

    boolean moduleAllowed(String relPath) {
        String topModule = relPath.contains("/") ? relPath.substring(0, relPath.indexOf('/')) : relPath;
        if (excludeModules != null && excludeModules.contains(topModule)) {
            return false;
        }
        if (includeModules == null || includeModules.isEmpty()) {
            return true;
        }
        return includeModules.contains(topModule);
    }
}