import { tool } from "@opencode-ai/plugin";
import { join, posix } from "node:path";

import { ResultReferenceStore } from "../../src/results/store.js";
import { ToolSessionContextStore } from "../../src/session/toolContextStore.js";
import {
  atomicWriteFile,
  ensureDirectory,
  readTextFile,
} from "../../src/utils/fileStore.js";
import { sanitizePersistentLine } from "../../src/utils/persistencePolicy.js";

const resultStore = new ResultReferenceStore();
const toolContextStore = new ToolSessionContextStore();
const initializePromise = Promise.all([
  resultStore.initialize(),
  toolContextStore.initialize(),
]);
const SKILLS_ROOT_DIR = ".opencode/skills";
const LEARNED_PATTERNS_MARKER = "## Learned Patterns";
let writeQueue: Promise<void> = Promise.resolve();

export default tool({
  description:
    "将已验证、可复用、非敏感的 workflow 或方法模式写入指定的 .opencode/skills 目录，由 opencode 自动识别和加载。",
  args: {
    reason: tool.schema
      .string()
      .describe("Why this workflow or method should be learned for future reuse."),
    skill_path: tool.schema
      .string()
      .describe("Target skill directory path relative to .opencode/skills, for example analytics/simulation-analysis/leakage or platform/governance-observability/meta."),
    pattern: tool.schema
      .string()
      .describe("A reusable workflow pattern written as one concise bullet-like sentence."),
    signal_type: tool.schema
      .string()
      .describe("Signal type, e.g. validated_workflow, successful_complex_convergence, analysis_method, tool_recovery_pattern."),
    confidence: tool.schema
      .number()
      .describe("Confidence between 0 and 1. Only very high-confidence patterns are stored as learned skills."),
    result_refs: tool.schema
      .array(tool.schema.string())
      .optional()
      .describe("Optional authorized result_ref list used only for evidence validation before persisting the skill."),
  },
  async execute(args, context) {
    await initializePromise;
    const sessionContext = await toolContextStore.read(context.sessionID);
    if (!sessionContext) {
      throw new Error(`session context not found for ${context.sessionID}`);
    }
    const skillPath = normalizeSkillPath(args.skill_path);
    if (!skillPath) {
      return JSON.stringify({
        ok: true,
        kind: "skill",
        decision: "rejected",
        detail: "invalid skill_path; expected a relative path under .opencode/skills",
      });
    }
    const pattern = sanitizePersistentLine(args.pattern, 320);
    if (!pattern) {
      return JSON.stringify({
        ok: true,
        kind: "skill",
        decision: "rejected",
        detail: "pattern rejected by persistence policy",
      });
    }
    if (args.confidence < 0.85) {
      return JSON.stringify({
        ok: true,
        kind: "skill",
        decision: "rejected",
        detail: "only very high-confidence patterns can be stored as skills",
      });
    }
    if (args.result_refs?.length) {
      await Promise.all(
        args.result_refs.map(async (resultRef) => {
          const record = await resultStore.peekAuthorized(resultRef, {
            actorKey: sessionContext.actorKey,
            projectId: sessionContext.projectId,
          });
          if (!record) {
            throw new Error(`unauthorized or missing result_ref: ${resultRef}`);
          }
        }),
      );
    }

    const result = await appendLearnedSkillPattern(skillPath, pattern);
    return JSON.stringify({
      ok: true,
      kind: "skill",
      decision: result.changed ? "accepted" : "deduped",
      detail: result.changed ? "skill file updated" : "pattern already existed",
      target: result.target,
    });
  },
});

const appendLearnedSkillPattern = async (skillPath: string, pattern: string) => {
  return serializeWrite(async () => {
    const target = join(SKILLS_ROOT_DIR, skillPath, "SKILL.md");
    const current = (await readTextFile(target)) ?? defaultLearnedSkill(skillPath);
    const existingPatterns = extractLearnedPatterns(current);
    if (existingPatterns.includes(pattern)) {
      return { changed: false, target };
    }

    const next = current.includes(LEARNED_PATTERNS_MARKER)
      ? current.replace(
          LEARNED_PATTERNS_MARKER,
          `${LEARNED_PATTERNS_MARKER}\n- ${pattern}`,
        )
      : `${current.trimEnd()}\n\n${LEARNED_PATTERNS_MARKER}\n- ${pattern}\n`;

    await ensureDirectory(join(SKILLS_ROOT_DIR, skillPath));
    await atomicWriteFile(target, next);
    return { changed: true, target };
  });
};

const serializeWrite = async <T>(task: () => Promise<T>) => {
  const run = writeQueue.catch(() => undefined).then(task);
  writeQueue = run.then(
    () => undefined,
    () => undefined,
  );
  return run;
};

const defaultLearnedSkill = (skillPath: string) => `---
name: tjwater-action-${toSkillName(skillPath)}
description: 由 skill_manager 在线追加的高置信度可复用 workflow。
version: 1.0.0
---

# learned skill

## 简介

记录由 \`skill_manager\` 在线追加的高置信度 workflow 模式。

## Learned Patterns
`;

const normalizeSkillPath = (rawSkillPath: string) => {
  const normalized = posix.normalize(rawSkillPath.trim().replace(/^\/+|\/+$/g, ""));
  if (!normalized || normalized === "." || normalized.startsWith("..")) {
    return null;
  }
  if (normalized === "SKILL.md" || normalized.endsWith("/SKILL.md")) {
    return null;
  }
  if (!/^[a-z0-9._/-]+$/i.test(normalized)) {
    return null;
  }
  return normalized;
};

const toSkillName = (skillPath: string) =>
  skillPath
    .split("/")
    .filter(Boolean)
    .join("-")
    .replace(/[^a-z0-9._-]+/gi, "-")
    .replace(/^-+|-+$/g, "")
    .slice(0, 120) || "generated-skill";

const extractLearnedPatterns = (content: string) => {
  if (!content.includes(LEARNED_PATTERNS_MARKER)) {
    return [];
  }
  return (content.split(LEARNED_PATTERNS_MARKER)[1] ?? "")
    .split("\n")
    .filter((line) => line.trim().startsWith("- "))
    .map((line) => line.trim().slice(2));
};