import fs from "fs";
import path from "path";
import matter from "gray-matter";

interface FileNode {
  name: string;
  type: "file" | "directory";
  children?: FileNode[];
}

interface SkillEntry {
  id: string;
  name: string;
  description: string;
  fileStructure: FileNode[];
  path: string;
  relatedTasks: { title: string; path: string }[];
}

function getFileStructure(dirPath: string): FileNode[] {
  const entries = fs.readdirSync(dirPath, { withFileTypes: true });
  const nodes: FileNode[] = [];

  for (const entry of entries) {
    if (
      entry.name === "node_modules" ||
      entry.name === ".git" ||
      entry.name === ".DS_Store"
    )
      continue;

    if (entry.isDirectory()) {
      nodes.push({
        name: entry.name,
        type: "directory",
        children: getFileStructure(path.join(dirPath, entry.name)),
      });
    } else {
      nodes.push({ name: entry.name, type: "file" });
    }
  }

  return nodes.sort((a, b) => {
    if (a.type === b.type) return a.name.localeCompare(b.name);
    return a.type === "directory" ? -1 : 1;
  });
}

function generateSkillsRegistry(): void {
  // Look for tasks in common locations
  const candidates = [
    path.join(__dirname, "..", "..", "tasks"),
    path.join(__dirname, "..", "..", "skillsbench", "tasks"),
    path.join(__dirname, "..", "tasks"),
  ];
  let tasksDir = candidates.find((d) => fs.existsSync(d)) || candidates[0];

  const outputPath = path.join(
    __dirname,
    "..",
    "src",
    "data",
    "skills-registry.json"
  );
  const skillsMap = new Map<string, SkillEntry>();

  if (!fs.existsSync(tasksDir)) {
    console.warn(
      "Tasks directory not found, skipping skills registry generation:",
      tasksDir
    );
    fs.mkdirSync(path.dirname(outputPath), { recursive: true });
    fs.writeFileSync(outputPath, "[]");
    return;
  }

  // Find all SKILL.md files recursively
  function findSkillFiles(dir: string): string[] {
    const results: string[] = [];
    const entries = fs.readdirSync(dir, { withFileTypes: true });

    for (const entry of entries) {
      const fullPath = path.join(dir, entry.name);
      if (
        entry.name === "node_modules" ||
        entry.name === ".git" ||
        entry.name === ".next"
      )
        continue;

      if (entry.isDirectory()) {
        results.push(...findSkillFiles(fullPath));
      } else if (entry.name === "SKILL.md") {
        results.push(fullPath);
      }
    }
    return results;
  }

  const skillFiles = findSkillFiles(tasksDir);
  console.log(`Found ${skillFiles.length} SKILL.md files`);

  for (const file of skillFiles) {
    try {
      const fileContent = fs.readFileSync(file, "utf-8");
      const { data, content } = matter(fileContent);
      const skillDir = path.dirname(file);
      const skillFolderName = path.basename(skillDir);
      const skillName = data.name || skillFolderName;
      const skillId = skillName.toLowerCase().replace(/\s+/g, "-");

      // Extract task name from path
      // Pattern: tasks/<task-name>/environment/skills/<skill-name>/SKILL.md
      const relPath = path.relative(tasksDir, file);
      const parts = relPath.split(path.sep);
      const taskName = parts[0]; // First component is the task name

      let skill = skillsMap.get(skillId);

      if (!skill) {
        // Get description from frontmatter or first paragraph of content
        let description = data.description || "";
        if (!description && content) {
          // Skip heading lines, get first non-empty paragraph
          const lines = content.split("\n");
          const nonHeadingLines: string[] = [];
          for (const line of lines) {
            if (line.startsWith("#")) continue;
            if (line.trim() === "" && nonHeadingLines.length > 0) break;
            if (line.trim()) nonHeadingLines.push(line.trim());
          }
          description = nonHeadingLines.join(" ").slice(0, 300);
        }

        skill = {
          id: skillId,
          name: skillName,
          description,
          fileStructure: getFileStructure(skillDir),
          path: `tasks/${path.relative(tasksDir, skillDir).split(path.sep).join("/")}`,
          relatedTasks: [],
        };
        skillsMap.set(skillId, skill);
      }

      // Add related task
      if (taskName && !skill.relatedTasks.some((t) => t.title === taskName)) {
        skill.relatedTasks.push({
          title: taskName,
          path: `/tasks/${taskName}`,
        });
      }
    } catch (error) {
      console.error(`Error processing skill at ${file}:`, error);
    }
  }

  const skills = Array.from(skillsMap.values()).sort((a, b) =>
    a.name.localeCompare(b.name)
  );

  const outputDir = path.dirname(outputPath);
  if (!fs.existsSync(outputDir)) {
    fs.mkdirSync(outputDir, { recursive: true });
  }

  fs.writeFileSync(outputPath, JSON.stringify(skills, null, 2));
  console.log(
    `Generated skills registry with ${skills.length} unique skills at ${outputPath}`
  );
}

generateSkillsRegistry();