/**
 * useProactive — React hook that drives tick generation for proactive mode.
 *
 * Mounted inside REPL.tsx when feature('PROACTIVE') || feature('KAIROS').
 * Generates <tick>HH:MM:SS</tick> prompts at a fixed interval while
 * proactive mode is active and not blocked.
 */
import { useEffect, useRef } from 'react'
import { TICK_TAG } from '../constants/xml.js'
import {
  isProactiveActive,
  isProactivePaused,
  isContextBlocked,
  setNextTickAt,
  shouldTick,
} from './index.js'

/** Default interval between ticks (ms). Prompt cache TTL is ~5 min so we
 *  stay well under that to keep the cache warm. */
const TICK_INTERVAL_MS = 30_000

type UseProactiveOpts = {
  isLoading: boolean
  queuedCommandsLength: number
  hasActiveLocalJsxUI: boolean
  isInPlanMode: boolean
  onSubmitTick: (prompt: string) => void
  onQueueTick: (prompt: string) => void
}

export function useProactive(opts: UseProactiveOpts): void {
  const optsRef = useRef(opts)
  optsRef.current = opts

  useEffect(() => {
    if (!isProactiveActive()) return

    let timer: ReturnType<typeof setTimeout> | null = null

    function scheduleTick(): void {
      const nextTs = Date.now() + TICK_INTERVAL_MS
      setNextTickAt(nextTs)

      timer = setTimeout(() => {
        timer = null

        // Guard: skip tick if any blocking condition is met
        if (!shouldTick()) {
          // Reschedule — conditions may clear later
          scheduleTick()
          return
        }

        const {
          isLoading,
          queuedCommandsLength,
          hasActiveLocalJsxUI,
          isInPlanMode,
        } = optsRef.current

        // Don't fire while a query is in-flight, plan mode is active,
        // a local JSX UI is showing, or commands are queued
        if (
          isLoading ||
          isInPlanMode ||
          hasActiveLocalJsxUI ||
          queuedCommandsLength > 0
        ) {
          scheduleTick()
          return
        }

        const tickContent = `<${TICK_TAG}>${new Date().toLocaleTimeString()}</${TICK_TAG}>`

        // If nothing is in the queue, submit directly; otherwise queue
        if (queuedCommandsLength === 0) {
          optsRef.current.onSubmitTick(tickContent)
        } else {
          optsRef.current.onQueueTick(tickContent)
        }

        // Schedule next tick
        scheduleTick()
      }, TICK_INTERVAL_MS)
    }

    scheduleTick()

    return () => {
      if (timer !== null) {
        clearTimeout(timer)
        timer = null
      }
      setNextTickAt(null)
    }
  }, [
    // Re-mount when proactive state changes
    isProactiveActive(),
    isProactivePaused(),
    isContextBlocked(),
  ])
}