/**
 * Global CLI flags parsed before command dispatch.
 *
 * Keeping this separate from per-command flag parsing so that
 * `gbrain --progress-json doctor` works: the global flag is stripped
 * before cli.ts looks at argv[0] for the subcommand.
 *
 * Threading: every command handler receives a resolved CliOptions object.
 * Shared-operation handlers see the same values via OperationContext.cliOpts.
 */

import type { ProgressOptions } from './progress.ts';

export interface CliOptions {
  quiet: boolean;
  progressJson: boolean;
  progressInterval: number; // ms
  /**
   * v0.31.1 (Issue #734, ENG-4): user-supplied per-call timeout for thin-client
   * routed MCP calls. `null` means "use the per-command default" (30s for most
   * ops, 180s for `think`). When set, applies to every routed call in the
   * current invocation.
   */
  timeoutMs: number | null;
  /**
   * v0.40.4 — `--explain` flag for `gbrain search/query`. Switches the
   * default formatter to a per-stage attribution view that shows
   * base_score + each boost stage's multiplier + rank delta from
   * the reranker. Has no effect on other commands.
   */
  explain: boolean;
}

export const DEFAULT_CLI_OPTIONS: CliOptions = {
  quiet: false,
  progressJson: false,
  progressInterval: 1000,
  timeoutMs: null,
  explain: false,
};

/**
 * Parse recognized global flags from the front / anywhere in argv and return
 * the resolved options plus the remaining argv (with global flags stripped).
 *
 * Recognized:
 *   --quiet
 *   --progress-json
 *   --progress-interval=<ms>
 *   --progress-interval <ms>   (space-separated form)
 *
 * Unknown flags are passed through unchanged — per-command parsers see them.
 */
export function parseGlobalFlags(argv: string[]): { cliOpts: CliOptions; rest: string[] } {
  const cliOpts: CliOptions = { ...DEFAULT_CLI_OPTIONS };
  const rest: string[] = [];

  for (let i = 0; i < argv.length; i++) {
    const a = argv[i];
    if (a === '--quiet') {
      cliOpts.quiet = true;
      continue;
    }
    if (a === '--progress-json') {
      cliOpts.progressJson = true;
      continue;
    }
    if (a === '--progress-interval' && i + 1 < argv.length) {
      const next = argv[i + 1];
      const parsed = parseInterval(next);
      if (parsed !== null) {
        cliOpts.progressInterval = parsed;
        i++;
        continue;
      }
      // not a number — let per-command parser handle; pass through
      rest.push(a);
      continue;
    }
    if (a.startsWith('--progress-interval=')) {
      const val = a.slice('--progress-interval='.length);
      const parsed = parseInterval(val);
      if (parsed !== null) {
        cliOpts.progressInterval = parsed;
        continue;
      }
      rest.push(a);
      continue;
    }
    // v0.31.1: --timeout=Ns or --timeout Ns. Accepts plain ms, "30s", "2m".
    if (a === '--timeout' && i + 1 < argv.length) {
      const next = argv[i + 1];
      const parsed = parseTimeout(next);
      if (parsed !== null) {
        cliOpts.timeoutMs = parsed;
        i++;
        continue;
      }
      rest.push(a);
      continue;
    }
    if (a.startsWith('--timeout=')) {
      const val = a.slice('--timeout='.length);
      const parsed = parseTimeout(val);
      if (parsed !== null) {
        cliOpts.timeoutMs = parsed;
        continue;
      }
      rest.push(a);
      continue;
    }
    // v0.40.4 — --explain for `gbrain search/query` per-stage attribution.
    if (a === '--explain') {
      cliOpts.explain = true;
      continue;
    }
    rest.push(a);
  }

  return { cliOpts, rest };
}

/**
 * v0.31.1: parse a timeout value. Accepts:
 *   "30000" / "30000ms" → 30000
 *   "30s"               → 30000
 *   "2m"                → 120000
 *   "1.5s"              → 1500
 * Returns null on parse failure (caller decides whether to error or fall through).
 */
export function parseTimeout(s: string): number | null {
  const m = /^([0-9]+(?:\.[0-9]+)?)(ms|s|m)?$/.exec(s.trim());
  if (!m) return null;
  const n = Number(m[1]);
  if (!Number.isFinite(n) || n <= 0) return null;
  const unit = m[2] ?? 'ms';
  const ms = unit === 'ms' ? n : unit === 's' ? n * 1000 : n * 60_000;
  return Math.floor(ms);
}

function parseInterval(s: string): number | null {
  const n = Number(s);
  if (!Number.isFinite(n) || n < 0) return null;
  return Math.floor(n);
}

/**
 * Map resolved CliOptions to ProgressOptions for createProgress().
 *
 * Mode resolution:
 *   --quiet          → 'quiet'
 *   --progress-json  → 'json'
 *   otherwise        → 'auto' (TTY: human-\r, non-TTY: human-plain)
 *
 * Agents that want structured events on a non-TTY stream must pass
 * --progress-json explicitly. Non-TTY default is plain human lines so
 * shell pipelines don't suddenly see JSON noise.
 */
export function cliOptsToProgressOptions(cliOpts: CliOptions): ProgressOptions {
  if (cliOpts.quiet) return { mode: 'quiet' };
  if (cliOpts.progressJson) return { mode: 'json', minIntervalMs: cliOpts.progressInterval };
  return { mode: 'auto', minIntervalMs: cliOpts.progressInterval };
}

// ---------------------------------------------------------------------------
// Module-level singleton (set once by cli.ts after parsing global flags; read
// by any bulk command that wants to construct a reporter). Same pattern as
// Commander's `program.opts()`. Also threaded into OperationContext for
// shared ops that run under the MCP server (which sets its own defaults).
// ---------------------------------------------------------------------------

let activeCliOptions: CliOptions = { ...DEFAULT_CLI_OPTIONS };

export function setCliOptions(opts: CliOptions): void {
  activeCliOptions = { ...opts };
}

export function getCliOptions(): CliOptions {
  return activeCliOptions;
}

/**
 * Reset singleton to defaults. Only used by tests.
 */
export function _resetCliOptionsForTest(): void {
  activeCliOptions = { ...DEFAULT_CLI_OPTIONS };
}

/**
 * Build the global-flag suffix to append to child `gbrain …` subprocess
 * commands so children inherit the parent's progress-mode.
 *
 * Returns a string ready to concat onto an execSync command string, with
 * a leading space when non-empty. E.g. " --progress-json --quiet".
 *
 * Empty string when nothing to propagate (so the child's behavior is
 * unchanged for the common no-flag case).
 */
export function childGlobalFlags(cliOpts?: CliOptions): string {
  const opts = cliOpts ?? activeCliOptions;
  const parts: string[] = [];
  if (opts.quiet) parts.push('--quiet');
  if (opts.progressJson) parts.push('--progress-json');
  if (opts.progressInterval !== DEFAULT_CLI_OPTIONS.progressInterval) {
    parts.push(`--progress-interval=${opts.progressInterval}`);
  }
  return parts.length > 0 ? ' ' + parts.join(' ') : '';
}

// ============================================================
// v0.36+ brain-health-100 wave: --background flag (D9 + T7)
//
// Per the locked decision: --background means submit-and-exit ALWAYS.
// Same semantics in TTY and cron. Composable in shell pipelines:
//
//   JOB=$(gbrain embed --stale --background | grep -oE 'job_id=[0-9]+' | cut -d= -f2)
//   gbrain jobs get $JOB
//
// `--background --follow` submits then execs `gbrain jobs follow <id>`
// so the user sees live stream while still getting durable queue
// semantics (worker survives if user disconnects).
//
// PGLite degrades to inline with a clear stderr note. NOT a no-op,
// NOT silent. Doc-stated semantic difference because PGLite has no
// worker daemon.
// ============================================================

import type { BrainEngine } from './engine.ts';
import { createHash } from 'crypto';

export interface MaybeBackgroundOpts {
  engine: BrainEngine;
  args: string[];
  jobName: string;
  paramBuilder: (args: string[]) => Record<string, unknown>;
  /** Source id for the idempotency key namespace. Default 'cli'. */
  source?: string;
}

/**
 * If `--background` is in args, submit a Minion job and return true
 * (caller should exit). Otherwise return false (caller does inline work).
 *
 * Strips `--background` and `--follow` from args before paramBuilder
 * runs so the param shape stays clean. On submit failure, prints stderr
 * + exits 1 (no orphan job; no silent fallthrough to inline).
 *
 * @returns true if backgrounded (caller MUST exit), false otherwise.
 */
export async function maybeBackground(opts: MaybeBackgroundOpts): Promise<boolean> {
  if (!opts.args.includes('--background')) return false;

  const filtered = opts.args.filter((a) => a !== '--background' && a !== '--follow');
  const params = opts.paramBuilder(filtered);
  const follow = opts.args.includes('--follow');
  const source = opts.source ?? 'cli';

  // PGLite has no worker daemon. Per the doc-stated semantics, degrade
  // to inline with a clear stderr note rather than silently failing.
  if (opts.engine.kind === 'pglite') {
    process.stderr.write(
      `[--background] PGLite has no worker daemon; running inline.\n`,
    );
    return false;  // caller runs inline
  }

  // D9: content-hash idempotency key. No time-slot — same intent = same
  // key. Failed-row replay is the doctor --remediate loop's job, not
  // the CLI --background path's job.
  const idempotency_key = `${source}:${opts.jobName}:${sha8(canonicalJson(params))}`;

  try {
    const { MinionQueue } = await import('./minions/queue.ts');
    const queue = new MinionQueue(opts.engine);
    const job = await queue.add(opts.jobName, params, {
      queue: 'default',
      idempotency_key,
      max_attempts: 2,
    });
    process.stdout.write(`job_id=${job.id}\n`);

    if (follow) {
      // exec `gbrain jobs follow <id>` so the user sees live stream
      // without losing the durable-queue submission.
      const { spawn } = await import('child_process');
      const cmd = process.argv[0] ?? 'bun';
      const script = process.argv[1] ?? '';
      const child = spawn(cmd, [script, 'jobs', 'follow', String(job.id)], {
        stdio: 'inherit',
      });
      await new Promise<void>((resolve) => child.on('exit', () => resolve()));
    }
    return true;  // caller exits
  } catch (e) {
    process.stderr.write(`[--background] submit failed: ${(e as Error).message}\n`);
    process.exit(1);
  }
}

function sha8(s: string): string {
  return createHash('sha256').update(s).digest('hex').slice(0, 8);
}

function canonicalJson(value: unknown): string {
  if (value === null || typeof value !== 'object') return JSON.stringify(value);
  if (Array.isArray(value)) return `[${value.map(canonicalJson).join(',')}]`;
  const keys = Object.keys(value as Record<string, unknown>).sort();
  return `{${keys.map((k) => `${JSON.stringify(k)}:${canonicalJson((value as Record<string, unknown>)[k])}`).join(',')}}`;
}