/**
 * Feedback Logger — writes structured feedback entries to FEEDBACK.md
 * alongside each skill's SKILL.md when failures are detected.
 *
 * Entries are appended automatically by the dojo when:
 * - A tool call fails after a skill was loaded (retries)
 * - The user corrects the agent after a skill was loaded
 * - A skill invocation exceeds the retry threshold
 *
 * The forge can read these entries to suggest SKILL.md improvements.
 */
import { existsSync, readFileSync, appendFileSync, statSync } from "node:fs";
import { join } from "node:path";

const SKILLS_DIR = join(process.env.HOME || "~", ".pi", "agent", "skills");
const MAX_FEEDBACK_SIZE = 50_000; // 50KB — rotate after this

export interface FeedbackEntry {
  /** Skill name */
  skill: string;
  /** ISO timestamp */
  timestamp: string;
  /** What went wrong */
  symptom: string;
  /** Error message or user correction text */
  detail: string;
  /** Category */
  category: "tool_error" | "user_correction" | "excessive_retries" | "timeout";
  /** Session ID for traceability */
  sessionId?: string;
}

/**
 * Append a feedback entry to a skill's FEEDBACK.md.
 * Creates the file if it doesn't exist. Rotates if too large.
 */
export function appendFeedback(entry: FeedbackEntry): boolean {
  const feedbackPath = join(SKILLS_DIR, entry.skill, "FEEDBACK.md");
  const skillDir = join(SKILLS_DIR, entry.skill);

  // Only write feedback for skills that exist
  if (!existsSync(join(skillDir, "SKILL.md"))) return false;

  // Rotate if file is too large
  if (existsSync(feedbackPath)) {
    try {
      const size = statSync(feedbackPath).size;
      if (size > MAX_FEEDBACK_SIZE) {
        // Keep only the last half
        const content = readFileSync(feedbackPath, "utf8");
        const lines = content.split("\n");
        const half = Math.floor(lines.length / 2);
        const trimmed = "<!-- Older entries rotated out -->\n\n" + lines.slice(half).join("\n");
        // Use writeFileSync to replace
        const { writeFileSync } = require("node:fs");
        writeFileSync(feedbackPath, trimmed, "utf8");
      }
    } catch {
      // Best effort
    }
  }

  const header = existsSync(feedbackPath) ? "" : `# Feedback Log

Auto-generated by skill-evolution. Records failures and corrections for this skill.
Used by the Skill Dojo to suggest improvements.

---

`;

  const dateStr = entry.timestamp.slice(0, 10);
  const timeStr = entry.timestamp.slice(11, 16);
  const sessionRef = entry.sessionId ? ` (session: \`${entry.sessionId.slice(0, 8)}\`)` : "";

  const block = `## ${dateStr} ${timeStr} — ${entry.category}${sessionRef}
- **Symptom:** ${entry.symptom}
- **Detail:** ${entry.detail}

`;

  try {
    appendFileSync(feedbackPath, header + block, "utf8");
    return true;
  } catch {
    return false;
  }
}

/**
 * Read recent feedback entries for a skill (last N entries).
 */
export function readFeedback(skill: string, maxEntries = 10): string {
  const feedbackPath = join(SKILLS_DIR, skill, "FEEDBACK.md");
  if (!existsSync(feedbackPath)) return "";

  try {
    const content = readFileSync(feedbackPath, "utf8");
    // Extract entries (each starts with ## date)
    const entries = content.split(/(?=^## \d{4}-)/m).filter(e => e.startsWith("## "));
    return entries.slice(-maxEntries).join("\n");
  } catch {
    return "";
  }
}

/**
 * Count feedback entries for a skill.
 */
export function countFeedback(skill: string): number {
  const feedbackPath = join(SKILLS_DIR, skill, "FEEDBACK.md");
  if (!existsSync(feedbackPath)) return 0;

  try {
    const content = readFileSync(feedbackPath, "utf8");
    return (content.match(/^## \d{4}-/gm) || []).length;
  } catch {
    return 0;
  }
}