// AVA — sticky app header: logo, audio source controls (segmented), demo BPM
// slider, BPM readout, and the beat indicator + "Set Beat" button side by side
// (hard requirement: that pairing is always visible in the header).

'use client'

import { useRef } from 'react'
import { AudioWaveform, Disc3, FileAudio, Mic, Square, Timer } from 'lucide-react'
import { Button } from '@/components/ui/button'
import { Slider } from '@/components/ui/slider'
import { BeatDot } from '@/components/ava/beat-dot'
import { tapBeat, useAudioSource } from '@/components/ava/audio-source'
import { useAvaStore } from '@/lib/store'
import { cn } from '@/lib/utils'

function SourceSegmentButton({
  active,
  onClick,
  icon: Icon,
  label,
  title,
  tone = 'default',
}: {
  active: boolean
  onClick: () => void
  icon: React.ComponentType<{ className?: string }>
  label: string
  title: string
  tone?: 'default' | 'stop'
}) {
  return (
    <button
      type="button"
      onClick={onClick}
      aria-pressed={active}
      title={title}
      className={cn(
        'flex h-11 items-center gap-1.5 rounded-md px-3 text-xs font-medium transition-colors',
        active
          ? 'bg-emerald-400/15 text-emerald-300 shadow-[inset_0_0_0_1px_rgba(52,211,153,0.35)]'
          : tone === 'stop'
            ? 'text-rose-300/70 hover:bg-zinc-800 hover:text-rose-300'
            : 'text-zinc-400 hover:bg-zinc-800 hover:text-zinc-100',
      )}
    >
      <Icon className="size-3.5" />
      {label}
    </button>
  )
}

function SourceControls() {
  const source = useAvaStore((s) => s.source)
  const setDemoBpm = useAvaStore((s) => s.setDemoBpm)
  const demoBpm = useAvaStore((s) => s.demoBpm)
  const { startDemo, startMic, startFile, stop } = useAudioSource()
  const fileInputRef = useRef<HTMLInputElement>(null)

  return (
    <div className="flex flex-wrap items-center gap-2">
      <div
        role="group"
        aria-label="Audio source"
        className="flex items-center gap-0.5 rounded-lg border border-zinc-800 bg-zinc-900/60 p-0.5"
      >
        <SourceSegmentButton
          active={source === 'demo'}
          onClick={() => void startDemo()}
          icon={Disc3}
          label="Demo"
          title="Built-in demo track (synthesized techno)"
        />
        <SourceSegmentButton
          active={source === 'mic'}
          onClick={() => void startMic()}
          icon={Mic}
          label="Mic"
          title="Live microphone / line-in"
        />
        <SourceSegmentButton
          active={source === 'file'}
          onClick={() => fileInputRef.current?.click()}
          icon={FileAudio}
          label="File"
          title="Play an audio file (loops)"
        />
        <SourceSegmentButton active={false} onClick={stop} icon={Square} label="Stop" title="Stop audio" tone="stop" />
      </div>

      {source === 'demo' && (
        <div className="flex h-11 items-center gap-2 rounded-lg border border-zinc-800 bg-zinc-900/60 px-3">
          <span className="font-mono text-[10px] tracking-widest text-emerald-400/80">DEMO</span>
          <Slider
            value={[demoBpm]}
            min={60}
            max={200}
            step={1}
            onValueChange={([v]) => setDemoBpm(v)}
            className="w-24"
            aria-label="Demo track tempo"
          />
          <span className="w-8 text-right font-mono text-xs tabular-nums text-zinc-300">{demoBpm}</span>
        </div>
      )}

      <input
        ref={fileInputRef}
        type="file"
        accept="audio/*"
        className="hidden"
        onChange={(e) => {
          const file = e.target.files?.[0]
          if (file) void startFile(file)
          e.target.value = ''
        }}
      />
    </div>
  )
}

function BpmReadout() {
  const bpm = useAvaStore((s) => s.stats?.beat.bpm ?? 0)
  return (
    <div className="text-right leading-none">
      <div className="font-mono text-xl font-bold tabular-nums text-emerald-400 sm:text-2xl">
        {bpm > 0 ? bpm.toFixed(1) : '—'}
      </div>
      <div className="mt-0.5 font-mono text-[9px] tracking-[0.2em] text-zinc-500">BPM</div>
    </div>
  )
}

export function AppHeader() {
  return (
    <header className="sticky top-0 z-40 border-b border-zinc-800/80 bg-zinc-950/80 backdrop-blur supports-[backdrop-filter]:bg-zinc-950/60">
      <div className="mx-auto flex max-w-[1800px] flex-wrap items-center gap-x-3 gap-y-2 px-3 py-2 sm:px-4">
        {/* logo */}
        <div className="order-1 flex items-center gap-2.5">
          <div className="grid size-9 place-items-center rounded-lg bg-emerald-400 shadow-[0_0_16px_rgba(52,211,153,0.35)]">
            <AudioWaveform className="size-5 text-zinc-950" aria-hidden />
          </div>
          <div>
            <h1 className="text-base font-bold leading-none tracking-wide">AVA</h1>
            <p className="mt-1 hidden text-[10px] leading-none tracking-[0.14em] text-zinc-500 sm:block">
              ADVANCED VISUALIZATION AGENT
            </p>
          </div>
        </div>

        {/* source controls — full row on mobile, after logo on desktop */}
        <div className="order-3 basis-full md:order-2 md:basis-auto">
          <SourceControls />
        </div>

        {/* BPM readout + beat indicator + Set Beat — always paired, always visible */}
        <div className="order-2 ml-auto flex items-center gap-2.5 md:order-3 sm:gap-3">
          <BpmReadout />
          <BeatDot size={44} />
          <Button
            onClick={tapBeat}
            className="h-11 gap-1.5 bg-emerald-400 px-3 font-semibold text-zinc-950 hover:bg-emerald-300 sm:px-4"
            title="Tap to set the tempo (or press Space)"
          >
            <Timer className="size-4" />
            <span className="hidden sm:inline">Set Beat</span>
            <span className="sm:hidden">Beat</span>
          </Button>
        </div>
      </div>
    </header>
  )
}