#!/usr/bin/env node
// Usage:
//   mosaic-discord check <binding> [--config PATH] [--repo PATH]
//   mosaic-discord run   <binding> [--config PATH] [--repo PATH] [--supervised]
//   mosaic-discord stop  <binding> [--config PATH]
//   mosaic-discord unlock <binding> [--config PATH]
//   mosaic-discord recover <binding> [--config PATH]
//   mosaic-discord reload <binding> [--config PATH]
//
// <binding> names <dataRoot>/discord/<binding>.json. The repository wrapper
// is scripts/discord.sh.
//
// check: binding, token file, context files and pi are validated; then the
// bot identity, guild and every listed channel are read over REST; then one
// gateway connection is made and closed after READY. Nothing is sent to a
// channel. A close code 4014 means the message-content intent is not
// granted in the developer portal.
// run: refuses when STOP exists or the outbox cannot be reconciled; otherwise
// starts the engine and the gateway and serves turns until SIGTERM, SIGINT
// or `stop`.
// stop: writes STOP and sends SIGTERM to the owner in run.lock, only when that
// process is alive and its start time and boot id match the record.
// unlock: writes STOP, then removes a run.lock whose owner is gone (crash,
// reboot, interrupted start). Refuses while the owner is live (use stop), alive
// with unverifiable identity, or recorded in a file it cannot read. `run` never reclaims on its own, and a
// claim that finds STOP after publishing releases itself, so unlock cannot
// race a start. Remove STOP to run again.
// recover: the supervised pre-start. Refuses while STOP is present or the
// binding is held by a live or unverifiable process; clears a lock whose
// owner is gone the way unlock does, then removes the STOP it wrote for
// that, so the run that follows can claim. Never removes a STOP an operator
// wrote. `run --supervised` does the same first thing itself; the service
// unit (scripts/discord-service.sh) uses that form, because systemd only
// honours a never-retry exit status from the main process, not from a
// pre-start command.
//
// reload: validates the binding file, then sends SIGHUP to the live owner in
// run.lock. The running process re-reads the file and applies guildName,
// channels, users and limits in place; a new channel is read over REST and
// must be in the bound guild. Any fixed key changed, an invalid file or a
// failed lookup refuses the reload and keeps the old binding. Each attempt is
// one line in reloads.jsonl. The service unit maps `systemctl --user reload`
// to the same signal.
//
// Exit codes: 0 ok; 1 operation failed; 2 invalid data or configuration;
// 3 refused by a brake (STOP present or the binding held; a supervisor must
// not retry); 4 usage.

import { existsSync, mkdirSync, mkdtempSync, writeFileSync, statSync, readdirSync } from "node:fs";
import { join, resolve } from "node:path";
import { createHash } from "node:crypto";
import { DiscordError } from "./errors.mjs";
import { defaultConfigPath, loadDataRoot, bindingPath, bindingDataDir, loadBinding, readToken, resolveContextFiles, resolveToolRoots, reloadDiff } from "./binding.mjs";
import { createRest } from "./rest.mjs";
import { createGateway, CONNECTOR_INTENTS } from "./gateway.mjs";
import { createEngine, buildPiArgs } from "./engine-pi.mjs";
import { TOOLS_ENV, enabledToolNames } from "./tools.mjs";
import { createSetsparkApi } from "./setspark.mjs";
import { assembleContext } from "./context.mjs";
import { createConnector } from "./connector.mjs";
import { ensureJournal, requestStop, stopRequested, readPid, stopTarget, writePid, clearPid, unlock, recover, appendReload, BRAKE_EXIT } from "./journal.mjs";

const USAGE = [
  "usage: mosaic-discord check <binding> [--config PATH] [--repo PATH]",
  "       mosaic-discord run   <binding> [--config PATH] [--repo PATH] [--supervised]",
  "       mosaic-discord stop  <binding> [--config PATH]",
  "       mosaic-discord unlock <binding> [--config PATH]",
  "       mosaic-discord recover <binding> [--config PATH]",
  "       mosaic-discord reload <binding> [--config PATH]",
].join("\n");

function parse(argv) {
  const opts = { command: null, binding: null, config: defaultConfigPath(), repo: process.cwd(), supervised: false };
  for (let i = 0; i < argv.length; i++) {
    const a = argv[i];
    if (a === "--config" || a === "--repo") {
      if (i + 1 >= argv.length) throw new DiscordError(`missing value for ${a}`, 4);
      opts[a.slice(2)] = resolve(argv[++i]);
    } else if (a === "--help" || a === "-h") {
      opts.command = "help";
    } else if (a === "--supervised") {
      opts.supervised = true;
    } else if (a.startsWith("--")) throw new DiscordError(`unknown argument: ${a}\n${USAGE}`, 4);
    else if (opts.command === null) opts.command = a;
    else if (opts.binding === null) opts.binding = a;
    else throw new DiscordError(`unexpected argument: ${a}\n${USAGE}`, 4);
  }
  if (opts.command === "help") return opts;
  if (!["check", "run", "stop", "unlock", "recover", "reload"].includes(opts.command)) throw new DiscordError(USAGE, 4);
  if (opts.binding === null) throw new DiscordError(`${opts.command} needs a binding name\n${USAGE}`, 4);
  if (opts.supervised && opts.command !== "run") throw new DiscordError(`--supervised applies to run only\n${USAGE}`, 4);
  return opts;
}

function say(msg) {
  process.stdout.write(`${msg}\n`);
}
function warn(msg) {
  process.stderr.write(`discord: ${msg}\n`);
}

// Everything that can be checked without the network, shared by check and run.
function prepare(opts) {
  const dataRoot = loadDataRoot(opts.config);
  const bindingFile = bindingPath(dataRoot, opts.binding);
  const binding = loadBinding(bindingFile);
  if (binding.name !== opts.binding) throw new DiscordError(`binding name ${JSON.stringify(binding.name)} does not match file name ${opts.binding}`);
  const contextFiles = resolveContextFiles(binding, opts.repo);
  const toolRoots = resolveToolRoots(binding, { dataRoot });
  const pi = join(opts.repo, "node_modules", ".bin", "pi");
  if (!existsSync(pi)) throw new DiscordError(`pi not found at ${pi}; run npm ci in the repository`);
  const journalDir = bindingDataDir(dataRoot, binding.name);
  const sessionDir = join(dataRoot, "sessions", `discord-${binding.name}`);
  return { dataRoot, bindingFile, binding, contextFiles, toolRoots, pi, journalDir, sessionDir };
}

async function check(opts) {
  const { binding, contextFiles, toolRoots, pi, journalDir, sessionDir } = prepare(opts);
  const token = readToken(binding);
  say(`binding ${binding.name}: seat ${binding.seat}, guild ${binding.guildId} (${binding.guildName}), ${binding.channels.length} channel(s), ${binding.users.length} user(s)`);
  say(`engine ${binding.engine.provider}/${binding.engine.model}:${binding.engine.thinking}, limits ${JSON.stringify(binding.limits)}`);
  say(`context ${contextFiles.length} file(s); pi ${pi}; journal ${journalDir}; session ${sessionDir}`);
  say(toolRoots ? `tools: ${enabledToolNames(toolRoots).join(",")}; roots ${toolRoots.roots.map((r) => `${r.name}=${r.path}${r.write ? " (writable)" : ""}`).join(" ")}, ${toolRoots.maxCallsPerTurn} calls/message, ${toolRoots.maxFileBytes} bytes/file${toolRoots.web ? `, web via ${toolRoots.web.searxng} (${toolRoots.web.maxFetchBytes} bytes/page)` : ""}${toolRoots.setspark ? `, setspark via ${toolRoots.setspark.baseUrl} as ${toolRoots.setspark.principal}` : ""}` : "tools: none");
  say(`token file mode 0600 ok; STOP ${stopRequested(journalDir) ? "PRESENT" : "absent"}`);

  const rest = createRest({ token, log: warn });
  const me = await rest.getMe();
  if (me.id !== binding.botUserId) throw new DiscordError(`token belongs to bot ${me.id}, binding says ${binding.botUserId}`);
  say(`rest: bot ${me.id} (${me.username}) matches binding`);
  const guild = await rest.getGuild(binding.guildId);
  say(`rest: guild ${guild.id} "${guild.name}" visible`);
  for (const c of binding.channels) {
    const ch = await rest.getChannel(c.id);
    if (ch.guild_id !== binding.guildId) throw new DiscordError(`channel ${c.id} is in guild ${ch.guild_id}, not ${binding.guildId}`);
    say(`rest: channel ${c.id} "#${ch.name}" type ${ch.type} (${c.mode}) visible`);
  }
  const gw = await rest.getGatewayBot();
  say(`rest: gateway ${gw.url}, sessions remaining today ${gw.session_start_limit ? gw.session_start_limit.remaining : "?"}`);

  const gateway = createGateway({ url: gw.url, token, intents: CONNECTOR_INTENTS });
  gateway.on("log", (m) => warn(`gateway: ${m}`));
  const outcome = await new Promise((resolveOutcome) => {
    const timer = setTimeout(() => resolveOutcome({ error: "no READY within 30 s" }), 30000);
    gateway.on("ready", (r) => {
      clearTimeout(timer);
      resolveOutcome({ ready: r });
    });
    gateway.on("fatal", (f) => {
      clearTimeout(timer);
      resolveOutcome({ fatal: f });
    });
    gateway.connect();
  });
  gateway.close(1000, "check complete");
  if (outcome.fatal) throw new DiscordError(`gateway close ${outcome.fatal.code}: ${outcome.fatal.reason}`);
  if (outcome.error) throw new DiscordError(`gateway: ${outcome.error}`, 1);
  const { ready } = outcome;
  if (!ready.user || ready.user.id !== binding.botUserId) throw new DiscordError(`gateway READY user ${ready.user && ready.user.id} does not match binding`);
  const inGuild = ready.guilds.some((g) => g.id === binding.guildId);
  if (!inGuild) throw new DiscordError(`gateway READY does not list guild ${binding.guildId}; is the bot in the server?`);
  say(`gateway: READY as ${ready.user.id}, intents ${CONNECTOR_INTENTS} accepted (message content granted), guild listed`);
  say("check passed; nothing was sent");
}

async function run(opts) {
  const { bindingFile, binding, contextFiles, toolRoots, pi, journalDir, sessionDir } = prepare(opts);
  const token = readToken(binding);
  ensureJournal(journalDir);
  if (opts.supervised) {
    const outcome = recover(journalDir);
    if (outcome === "cleared") warn("supervised start: run.lock left by a process that is gone was removed");
  }
  if (stopRequested(journalDir)) throw new DiscordError(`STOP is present in ${journalDir}; remove it to run`, BRAKE_EXIT);
  writePid(journalDir, process.pid);
  const cleanupPid = () => clearPid(journalDir, process.pid);
  try {
    await runClaimed();
  } catch (err) {
    cleanupPid();
    throw err;
  }

  async function runClaimed() {
    mkdirSync(sessionDir, { recursive: true, mode: 0o700 });
    const launches = join(journalDir, "launches");
    mkdirSync(launches, { recursive: true, mode: 0o700 });
    const launch = mkdtempSync(join(launches, "launch."));
    const snapshot = assembleContext(contextFiles, binding);
    const promptFile = join(launch, "context.md");
    writeFileSync(promptFile, snapshot.text, { mode: 0o600 });
    writeFileSync(join(launch, "context.sha256"), `${snapshot.sha256}  context.md\n`, { mode: 0o600 });
    const continueSession = existsSync(sessionDir) && statSync(sessionDir).isDirectory() && hasJsonl(sessionDir);

    const rest = createRest({ token, log: warn });
    const gw = await rest.getGatewayBot();
    const gateway = createGateway({ url: gw.url, token, intents: CONNECTOR_INTENTS });
    gateway.on("log", (m) => warn(`gateway: ${m}`));
    gateway.on("ready", (r) => warn(`gateway: READY as ${r.user && r.user.id}, session ${r.sessionId}`));
    gateway.on("resumed", () => warn("gateway: RESUMED"));
    gateway.on("closed", (c) => warn(`gateway: closed ${c.code} ${c.reason} reconnect=${c.willReconnect}`));

    const engine = createEngine({
      command: pi,
      args: buildPiArgs({ ...binding.engine, sessionDir, appendSystemPromptFile: promptFile, continueSession, tools: toolRoots }),
      cwd: opts.repo,
      env: { ...process.env, MOSAIC_AGENT_NAME: binding.seat, ...(toolRoots ? { [TOOLS_ENV]: JSON.stringify(toolRoots) } : {}) },
      log: warn,
      onExit: (e) => {
        warn(`engine exited: ${JSON.stringify(e)}; stopping`);
        shutdown(1);
      },
    });

    // The connector's own SetSpark client (bind and approvals) uses the same
    // key as the model's verbs; without a setspark key it has none, and an
    // approval request from the model is refused.
    const api = binding.tools && binding.tools.setspark ? createSetsparkApi(binding.tools.setspark) : null;
    const connector = createConnector({ binding, journalDir, rest, gateway, engine, api, log: warn });
    let shuttingDown = false;
    let exitCode = 0;
    const shutdown = (code) => {
      if (shuttingDown) return;
      shuttingDown = true;
      exitCode = code;
      warn("stopping: finishing in-flight turns");
      connector.stop().catch((err) => warn(`stop failed: ${err.message}`)).finally(() => {
        cleanupPid();
        process.exit(exitCode);
      });
    };
    gateway.on("fatal", (f) => {
      warn(`gateway fatal close ${f.code}: ${f.reason}`);
      shutdown(2);
    });
    process.on("SIGTERM", () => shutdown(0));
    process.on("SIGINT", () => shutdown(0));

    // Reload on SIGHUP: re-read the file, refuse anything that is not a
    // reloadable difference, verify new channels over REST, then swap.
    // Attempts are serialized; the outcome is journaled and logged, and a
    // refusal leaves the binding as it was.
    const reloadNow = async () => {
      const at = new Date().toISOString();
      try {
        const next = loadBinding(bindingFile);
        if (next.name !== binding.name) throw new DiscordError(`reload: name ${JSON.stringify(next.name)} does not match ${binding.name}`);
        const diff = reloadDiff(connector.binding, next);
        for (const id of diff.channels.added) {
          const ch = await rest.getChannel(id);
          if (ch.guild_id !== next.guildId) throw new DiscordError(`reload: channel ${id} is in guild ${ch.guild_id}, not ${next.guildId}`);
        }
        connector.reload(next);
        appendReload(journalDir, { at, outcome: "applied", ...diff });
        const n = (d) => `+${d.added.length} -${d.removed.length} ~${d.changed.length}`;
        warn(`reload applied: channels ${n(diff.channels)}, users ${n(diff.users)}, limits ${diff.limits.length ? diff.limits.join(",") : "unchanged"}${diff.guildName ? ", guildName" : ""}`);
      } catch (err) {
        appendReload(journalDir, { at, outcome: "refused", error: err.message });
        warn(`reload refused, binding unchanged: ${err.message}`);
      }
    };
    let reloadChain = Promise.resolve();
    process.on("SIGHUP", () => {
      reloadChain = reloadChain.then(reloadNow, reloadNow);
    });

    const started = await connector.start();
    say(`run ${binding.name}: pid ${process.pid}, ${started.inbox} inbox id(s), ${started.reconciled.length} reconciled, context sha256 ${snapshot.sha256}, session ${continueSession ? "continued" : "new"}`);
    say(`stop with: scripts/discord.sh stop ${binding.name}`);
  }
}

function hasJsonl(dir) {
  try {
    return readdirSync(dir).some((f) => f.endsWith(".jsonl"));
  } catch {
    return false;
  }
}

function stop(opts) {
  const dataRoot = loadDataRoot(opts.config);
  const binding = loadBinding(bindingPath(dataRoot, opts.binding));
  const journalDir = bindingDataDir(dataRoot, binding.name);
  ensureJournal(journalDir);
  const path = requestStop(journalDir, "cli stop");
  say(`STOP written: ${path}`);
  const pid = stopTarget(journalDir);
  if (pid !== null) {
    process.kill(pid, "SIGTERM");
    say(`SIGTERM sent to pid ${pid}; the current turn finishes or times out, then it exits`);
  } else if (readPid(journalDir) !== null) {
    say("run.lock exists but its process is gone, is a different process, or cannot be verified; nothing signaled. STOP stays in place; `unlock` clears a lock whose owner is gone");
  } else {
    say("no running connector found for this binding");
  }
}

function unlockCommand(opts) {
  const dataRoot = loadDataRoot(opts.config);
  const binding = loadBinding(bindingPath(dataRoot, opts.binding));
  const journalDir = bindingDataDir(dataRoot, binding.name);
  ensureJournal(journalDir);
  const cleared = unlock(journalDir);
  say(`STOP written: ${join(journalDir, "STOP")}`);
  if (cleared === false) say("no run.lock for this binding");
  else if (cleared === null) say("run.lock removed; it had no owner record (interrupted start)");
  else say(`run.lock removed; its owner pid ${cleared.pid} is gone`);
  say("remove STOP to run again");
}

function reloadCommand(opts) {
  const dataRoot = loadDataRoot(opts.config);
  const binding = loadBinding(bindingPath(dataRoot, opts.binding));
  if (binding.name !== opts.binding) throw new DiscordError(`binding name ${JSON.stringify(binding.name)} does not match file name ${opts.binding}`);
  const journalDir = bindingDataDir(dataRoot, binding.name);
  ensureJournal(journalDir);
  const pid = stopTarget(journalDir);
  if (pid === null) throw new DiscordError("no running connector for this binding; the file is valid and applies at the next start", 1);
  process.kill(pid, "SIGHUP");
  say(`SIGHUP sent to pid ${pid}; the outcome is the last line of ${join(journalDir, "reloads.jsonl")} and in its log`);
}

function recoverCommand(opts) {
  const dataRoot = loadDataRoot(opts.config);
  const binding = loadBinding(bindingPath(dataRoot, opts.binding));
  const journalDir = bindingDataDir(dataRoot, binding.name);
  ensureJournal(journalDir);
  const outcome = recover(journalDir);
  if (outcome === "cleared") say("run.lock left by a process that is gone was removed; STOP is absent; ready to run");
  else say("no lock and no STOP; ready to run");
}

async function main() {
  const opts = parse(process.argv.slice(2));
  if (opts.command === "help") {
    say(USAGE);
    return 0;
  }
  if (opts.command === "check") await check(opts);
  else if (opts.command === "run") await run(opts);
  else if (opts.command === "unlock") unlockCommand(opts);
  else if (opts.command === "recover") recoverCommand(opts);
  else if (opts.command === "reload") reloadCommand(opts);
  else stop(opts);
  return opts.command === "run" ? null : 0;
}

main().then((code) => {
  if (code !== null) process.exit(code);
}).catch((err) => {
  const code = err instanceof DiscordError ? err.exitCode : 1;
  warn(err.message);
  if (err.details && err.details.nonces) warn(`nonces: ${err.details.nonces.join(", ")}`);
  process.exit(code);
});