import { readFileSync, writeFileSync, readdirSync, existsSync } from "node:fs";
import { join, dirname } from "node:path";
import { fileURLToPath } from "node:url";
import { getAllTools, ESSENTIAL_TOOLS } from "../../src/mcp/tools-registry.js";
import { ADAPTERS } from "../../src/cli/connect/index.js";

const HERE = dirname(fileURLToPath(import.meta.url));
const ROOT = join(HERE, "..", "..");
const SKILLS = join(ROOT, "plugin", "skills");
const SRC = join(ROOT, "src");

const check = process.argv.includes("--check");

function clean(s: string): string {
  return s.replace(/\s*[—–]\s*/g, ", ");
}

function block(key: string, body: string): { open: string; close: string; full: string } {
  const open = `<!-- AUTOGEN:${key} START - generated by scripts/skills/generate.ts, do not edit by hand -->`;
  const close = `<!-- AUTOGEN:${key} END -->`;
  return { open, close, full: `${open}\n${body.trim()}\n${close}` };
}

function applyBlock(file: string, key: string, body: string): void {
  const { open, close, full } = block(key, body);
  const existing = existsSync(file) ? readFileSync(file, "utf8") : "";
  let next: string;
  if (existing.includes(open) && existing.includes(close)) {
    const start = existing.indexOf(open);
    const end = existing.indexOf(close) + close.length;
    next = existing.slice(0, start) + full + existing.slice(end);
  } else if (existing.trim()) {
    next = `${existing.trimEnd()}\n\n${full}\n`;
  } else {
    next = `${full}\n`;
  }
  if (check) {
    if (existing !== next) {
      console.error(`DRIFT: ${file.replace(ROOT + "/", "")} (AUTOGEN:${key} out of date — run \`npm run skills:gen\`)`);
      process.exitCode = 1;
    }
    return;
  }
  if (existing !== next) {
    writeFileSync(file, next);
    console.log(`wrote AUTOGEN:${key} -> ${file.replace(ROOT + "/", "")}`);
  }
}

function walk(dir: string, out: string[] = []): string[] {
  for (const e of readdirSync(dir, { withFileTypes: true })) {
    const full = join(dir, e.name);
    if (e.isDirectory()) {
      if (e.name === "node_modules" || e.name === "dist") continue;
      walk(full, out);
    } else if (e.name.endsWith(".ts")) {
      out.push(full);
    }
  }
  return out;
}

function mdEscape(s: string): string {
  return clean(s.replace(/\|/g, "\\|").replace(/\n/g, " ")).trim();
}

function tools(): string {
  const all = getAllTools();
  const lines = [
    `agentmemory exposes ${all.length} MCP tools. ${ESSENTIAL_TOOLS.size} are in the lean core set (\`--tools core\` or \`AGENTMEMORY_TOOLS=core\`); the rest load with \`--tools all\` (default).`,
    "",
    "| Tool | Core | Parameters | Purpose |",
    "| --- | --- | --- | --- |",
  ];
  for (const t of all.sort((a, b) => a.name.localeCompare(b.name))) {
    const required = new Set(t.inputSchema.required ?? []);
    const params = Object.entries(t.inputSchema.properties ?? {})
      .map(([n, s]) => `\`${n}\`${required.has(n) ? "*" : ""}: ${s.type}`)
      .join(", ") || "none";
    const core = ESSENTIAL_TOOLS.has(t.name) ? "yes" : "";
    lines.push(`| \`${t.name}\` | ${core} | ${mdEscape(params)} | ${mdEscape(t.description)} |`);
  }
  lines.push("", "`*` marks required parameters.");
  return lines.join("\n");
}

function rest(): string {
  const text = readFileSync(join(SRC, "triggers", "api.ts"), "utf8");
  const found: { path: string; method: string }[] = [];
  const re = /api_path:\s*"([^"]+)"/g;
  let m: RegExpExecArray | null;
  while ((m = re.exec(text)) !== null) {
    const path = m[1];
    const win = text.slice(Math.max(0, m.index - 140), m.index + 140);
    const mm = /http_method:\s*"([A-Z]+)"/.exec(win);
    found.push({ path, method: mm ? mm[1] : "POST" });
  }
  const seen = new Set<string>();
  const rows = found
    .filter((e) => (seen.has(e.path) ? false : (seen.add(e.path), true)))
    .sort((a, b) => a.path.localeCompare(b.path));
  const lines = [
    `The REST API is the primary surface. All paths are under \`http://localhost:3111\` (override with \`--port\`). When \`AGENTMEMORY_SECRET\` is set, send \`Authorization: Bearer $AGENTMEMORY_SECRET\`; localhost is otherwise open.`,
    "",
    `${rows.length} registered endpoints:`,
    "",
    "| Method | Path |",
    "| --- | --- |",
    ...rows.map((e) => `| ${e.method} | \`${e.path}\` |`),
  ];
  return lines.join("\n");
}

function env(): string {
  const files = walk(SRC);
  const vars = new Set<string>();
  for (const f of files) {
    const text = readFileSync(f, "utf8");
    const re = /AGENTMEMORY_[A-Z0-9_]+/g;
    let m: RegExpExecArray | null;
    while ((m = re.exec(text)) !== null) {
      if (!m[0].endsWith("__")) vars.add(m[0]);
    }
  }
  const sorted = [...vars].sort();
  const lines = [
    `Configuration is read from the environment and from \`~/.agentmemory/.env\` (no \`export\` prefix). ${sorted.length} recognized variables:`,
    "",
    ...sorted.map((v) => `- \`${v}\``),
  ];
  return lines.join("\n");
}

function agents(): string {
  const lines = [
    `\`agentmemory connect <agent>\` wires the memory server into a host agent. ${ADAPTERS.length} adapters:`,
    "",
    "| Agent | Name | Protocol |",
    "| --- | --- | --- |",
  ];
  for (const a of [...ADAPTERS].sort((x, y) => x.name.localeCompare(y.name))) {
    const note = (a.protocolNote ?? "").replace(/^[→\s]+/, "");
    lines.push(`| ${mdEscape(a.displayName)} | \`${a.name}\` | ${mdEscape(note) || "MCP"} |`);
  }
  return lines.join("\n");
}

function hooks(): string {
  const file = join(ROOT, "plugin", "hooks", "hooks.json");
  const json = JSON.parse(readFileSync(file, "utf8")) as { hooks?: Record<string, unknown> };
  const events = Object.keys(json.hooks ?? {}).sort();
  const lines = [
    `The Claude Code plugin registers hooks on ${events.length} lifecycle events to capture observations automatically:`,
    "",
    ...events.map((e) => `- \`${e}\``),
  ];
  return lines.join("\n");
}

applyBlock(join(SKILLS, "agentmemory-mcp-tools", "REFERENCE.md"), "tools", tools());
applyBlock(join(SKILLS, "agentmemory-rest-api", "REFERENCE.md"), "rest", rest());
applyBlock(join(SKILLS, "agentmemory-config", "REFERENCE.md"), "env", env());
applyBlock(join(SKILLS, "agentmemory-agents", "REFERENCE.md"), "agents", agents());
applyBlock(join(SKILLS, "agentmemory-hooks", "REFERENCE.md"), "hooks", hooks());

if (check && process.exitCode) {
  console.error("\nSkill reference docs are stale. Run: npm run skills:gen");
} else if (!check) {
  console.log("skills reference generation complete");
}