import { useState, useRef, useCallback, useEffect } from 'react'
import { X, Eye, EyeSlash, GithubLogo, SignOut } from '@phosphor-icons/react'
import { GitHubDeviceFlow } from './GitHubDeviceFlow'
import type { Settings } from '../types'

interface SettingsPanelProps {
  open: boolean
  settings: Settings
  onSave: (settings: Settings) => void
  onClose: () => void
}


interface KeyFieldProps {
  label: string
  placeholder: string
  value: string
  onChange: (value: string) => void
  onClear: () => void
}

function KeyField({ label, placeholder, value, onChange, onClear }: KeyFieldProps) {
  const [revealed, setRevealed] = useState(false)
  const inputRef = useRef<HTMLInputElement>(null)

  return (
    <div style={{ display: 'flex', flexDirection: 'column', gap: 6 }}>
      <label style={{ fontSize: 12, fontWeight: 500, color: 'var(--foreground)' }}>{label}</label>
      <div style={{ position: 'relative', display: 'flex', alignItems: 'center' }}>
        <input
          ref={inputRef}
          type={revealed ? 'text' : 'password'}
          value={value}
          onChange={e => onChange(e.target.value)}
          placeholder={placeholder}
          className="w-full border border-border bg-transparent text-foreground rounded"
          style={{ fontSize: 13, padding: '8px 60px 8px 10px', outline: 'none', fontFamily: 'inherit' }}
          autoComplete="off"
          data-testid={`settings-key-${label.toLowerCase().replace(/\s+/g, '-')}`}
        />
        <div style={{ position: 'absolute', right: 8, display: 'flex', gap: 4, alignItems: 'center' }}>
          {value && (
            <>
              <button
                className="border-none bg-transparent p-1 text-muted-foreground cursor-pointer hover:text-foreground"
                onClick={() => setRevealed(r => !r)}
                title={revealed ? 'Hide key' : 'Reveal key'}
                type="button"
              >
                {revealed ? <EyeSlash size={14} /> : <Eye size={14} />}
              </button>
              <button
                className="border-none bg-transparent p-1 text-muted-foreground cursor-pointer hover:text-foreground"
                onClick={() => { onClear(); setRevealed(false) }}
                title="Clear key"
                type="button"
                data-testid={`clear-${label.toLowerCase().replace(/\s+/g, '-')}`}
              >
                <X size={14} />
              </button>
            </>
          )}
        </div>
      </div>
    </div>
  )
}

// --- GitHub OAuth Section ---

interface GitHubSectionProps {
  githubUsername: string | null
  githubToken: string | null
  onConnected: (token: string, username: string) => void
  onDisconnect: () => void
}

function GitHubSection({ githubUsername, githubToken, onConnected, onDisconnect }: GitHubSectionProps) {
  const isConnected = !!githubToken && !!githubUsername

  if (isConnected) {
    return <GitHubConnectedRow username={githubUsername!} onDisconnect={onDisconnect} />
  }

  return <GitHubDeviceFlow onConnected={onConnected} />
}

function GitHubConnectedRow({ username, onDisconnect }: { username: string; onDisconnect: () => void }) {
  return (
    <div style={{ display: 'flex', alignItems: 'center', gap: 12 }}>
      <div
        className="flex items-center gap-2 border border-border rounded px-3 py-2 flex-1"
        style={{ minHeight: 36 }}
        data-testid="github-connected"
      >
        <GithubLogo size={16} weight="fill" style={{ color: 'var(--foreground)' }} />
        <span style={{ fontSize: 13, color: 'var(--foreground)', fontWeight: 500 }}>{username}</span>
        <span style={{ fontSize: 12, color: 'var(--muted-foreground)' }}>Connected</span>
      </div>
      <button
        className="border border-border bg-transparent text-muted-foreground rounded cursor-pointer hover:text-foreground hover:border-foreground"
        style={{ fontSize: 12, padding: '6px 12px', display: 'flex', alignItems: 'center', gap: 4 }}
        onClick={onDisconnect}
        title="Disconnect GitHub account"
        data-testid="github-disconnect"
      >
        <SignOut size={14} />
        Disconnect
      </button>
    </div>
  )
}

// --- Settings Panel ---

export function SettingsPanel({ open, settings, onSave, onClose }: SettingsPanelProps) {
  if (!open) return null
  return <SettingsPanelInner settings={settings} onSave={onSave} onClose={onClose} />
}

function SettingsPanelInner({ settings, onSave, onClose }: Omit<SettingsPanelProps, 'open'>) {
  const [openaiKey, setOpenaiKey] = useState(settings.openai_key ?? '')
  const [googleKey, setGoogleKey] = useState(settings.google_key ?? '')
  const [githubToken, setGithubToken] = useState(settings.github_token)
  const [githubUsername, setGithubUsername] = useState(settings.github_username)
  const [pullInterval, setPullInterval] = useState(settings.auto_pull_interval_minutes ?? 5)
  const [updateChannel, setUpdateChannel] = useState(settings.update_channel ?? 'stable')
  const [crashReporting, setCrashReporting] = useState(settings.crash_reporting_enabled ?? false)
  const [analytics, setAnalytics] = useState(settings.analytics_enabled ?? false)
  const panelRef = useRef<HTMLDivElement>(null)

  // Auto-focus first input when settings panel opens
  useEffect(() => {
    const timer = setTimeout(() => {
      const input = panelRef.current?.querySelector('input')
      input?.focus()
    }, 50)
    return () => clearTimeout(timer)
  }, [])

  const buildSettings = useCallback((ghOverride?: { token: string | null; username: string | null }): Settings => ({
    openai_key: openaiKey.trim() || null,
    google_key: googleKey.trim() || null,
    github_token: ghOverride ? ghOverride.token : (githubToken ?? null),
    github_username: ghOverride ? ghOverride.username : (githubUsername ?? null),
    auto_pull_interval_minutes: pullInterval,
    telemetry_consent: (crashReporting || analytics) ? true : (settings.telemetry_consent === null ? null : false),
    crash_reporting_enabled: crashReporting,
    analytics_enabled: analytics,
    anonymous_id: (crashReporting || analytics) ? (settings.anonymous_id ?? crypto.randomUUID()) : settings.anonymous_id,
    update_channel: updateChannel === 'stable' ? null : updateChannel,
  }), [openaiKey, googleKey, githubToken, githubUsername, pullInterval, updateChannel, crashReporting, analytics, settings.telemetry_consent, settings.anonymous_id])

  const handleSave = () => {
    onSave(buildSettings())
    onClose()
  }

  const handleGitHubConnected = useCallback((token: string, username: string) => {
    setGithubToken(token)
    setGithubUsername(username)
    onSave(buildSettings({ token, username }))
  }, [onSave, buildSettings])

  const handleGitHubDisconnect = useCallback(() => {
    setGithubToken(null)
    setGithubUsername(null)
    onSave(buildSettings({ token: null, username: null }))
  }, [onSave, buildSettings])

  const handleKeyDown = (e: React.KeyboardEvent) => {
    if (e.key === 'Escape') {
      e.stopPropagation()
      onClose()
    }
    if (e.key === 'Enter' && (e.metaKey || e.ctrlKey)) {
      e.preventDefault()
      handleSave()
    }
  }

  return (
    <div
      className="fixed inset-0 flex items-center justify-center z-50"
      style={{ background: 'rgba(0,0,0,0.4)' }}
      onClick={e => { if (e.target === e.currentTarget) onClose() }}
      onKeyDown={handleKeyDown}
      data-testid="settings-panel"
    >
      <div
        ref={panelRef}
        className="bg-background border border-border rounded-lg shadow-xl"
        style={{ width: 520, maxHeight: '80vh', display: 'flex', flexDirection: 'column' }}
      >
        <SettingsHeader onClose={onClose} />
        <SettingsBody
          openaiKey={openaiKey} setOpenaiKey={setOpenaiKey}
          googleKey={googleKey} setGoogleKey={setGoogleKey}
          githubToken={githubToken ?? null} githubUsername={githubUsername ?? null}
          onGitHubConnected={handleGitHubConnected} onGitHubDisconnect={handleGitHubDisconnect}
          pullInterval={pullInterval} setPullInterval={setPullInterval}
          updateChannel={updateChannel} setUpdateChannel={setUpdateChannel}
          crashReporting={crashReporting} setCrashReporting={setCrashReporting}
          analytics={analytics} setAnalytics={setAnalytics}
        />
        <SettingsFooter onClose={onClose} onSave={handleSave} />
      </div>
    </div>
  )
}

function SettingsHeader({ onClose }: { onClose: () => void }) {
  return (
    <div
      className="flex items-center justify-between shrink-0"
      style={{ height: 56, padding: '0 24px', borderBottom: '1px solid var(--border)' }}
    >
      <span style={{ fontSize: 16, fontWeight: 600, color: 'var(--foreground)' }}>Settings</span>
      <button
        className="border-none bg-transparent p-1 text-muted-foreground cursor-pointer hover:text-foreground"
        onClick={onClose}
        title="Close settings"
      >
        <X size={16} />
      </button>
    </div>
  )
}

interface SettingsBodyProps {
  openaiKey: string; setOpenaiKey: (v: string) => void
  googleKey: string; setGoogleKey: (v: string) => void
  githubToken: string | null; githubUsername: string | null
  onGitHubConnected: (token: string, username: string) => void
  onGitHubDisconnect: () => void
  pullInterval: number; setPullInterval: (v: number) => void
  updateChannel: string; setUpdateChannel: (v: string) => void
  crashReporting: boolean; setCrashReporting: (v: boolean) => void
  analytics: boolean; setAnalytics: (v: boolean) => void
}

function SettingsBody(props: SettingsBodyProps) {
  return (
    <div style={{ padding: 24, display: 'flex', flexDirection: 'column', gap: 20, overflow: 'auto' }}>
      <div>
        <div style={{ fontSize: 13, fontWeight: 600, color: 'var(--foreground)', marginBottom: 4 }}>AI Provider Keys</div>
        <div style={{ fontSize: 12, color: 'var(--muted-foreground)', lineHeight: 1.5 }}>
          API keys are stored locally on your device. Never sent to our servers.
        </div>
      </div>

      <KeyField label="OpenAI" placeholder="sk-..." value={props.openaiKey} onChange={props.setOpenaiKey} onClear={() => props.setOpenaiKey('')} />
      <KeyField label="Google AI" placeholder="AIza..." value={props.googleKey} onChange={props.setGoogleKey} onClear={() => props.setGoogleKey('')} />

      <div style={{ height: 1, background: 'var(--border)' }} />

      <div>
        <div style={{ fontSize: 13, fontWeight: 600, color: 'var(--foreground)', marginBottom: 4 }}>GitHub</div>
        <div style={{ fontSize: 12, color: 'var(--muted-foreground)', lineHeight: 1.5 }}>
          Connect your GitHub account to clone and sync vaults.
        </div>
      </div>

      <GitHubSection
        githubUsername={props.githubUsername}
        githubToken={props.githubToken}
        onConnected={props.onGitHubConnected}
        onDisconnect={props.onGitHubDisconnect}
      />

      <div style={{ height: 1, background: 'var(--border)' }} />

      <div>
        <div style={{ fontSize: 13, fontWeight: 600, color: 'var(--foreground)', marginBottom: 4 }}>Sync</div>
        <div style={{ fontSize: 12, color: 'var(--muted-foreground)', lineHeight: 1.5 }}>
          Automatically pull vault changes from Git in the background.
        </div>
      </div>

      <div style={{ display: 'flex', flexDirection: 'column', gap: 6 }}>
        <label style={{ fontSize: 12, fontWeight: 500, color: 'var(--foreground)' }}>Pull interval (minutes)</label>
        <select
          value={props.pullInterval}
          onChange={(e) => props.setPullInterval(Number(e.target.value))}
          className="border border-border bg-transparent text-foreground rounded"
          style={{ fontSize: 13, padding: '8px 10px', outline: 'none', fontFamily: 'inherit' }}
          data-testid="settings-pull-interval"
        >
          <option value={1}>1</option>
          <option value={2}>2</option>
          <option value={5}>5</option>
          <option value={10}>10</option>
          <option value={15}>15</option>
          <option value={30}>30</option>
        </select>
      </div>

      <div style={{ height: 1, background: 'var(--border)' }} />

      <div>
        <div style={{ fontSize: 13, fontWeight: 600, color: 'var(--foreground)', marginBottom: 4 }}>Updates</div>
        <div style={{ fontSize: 12, color: 'var(--muted-foreground)', lineHeight: 1.5 }}>
          Canary builds include the latest features but may be less stable. Restart required after changing.
        </div>
      </div>

      <div style={{ display: 'flex', flexDirection: 'column', gap: 6 }}>
        <label style={{ fontSize: 12, fontWeight: 500, color: 'var(--foreground)' }}>Update channel</label>
        <select
          value={props.updateChannel}
          onChange={(e) => props.setUpdateChannel(e.target.value)}
          className="border border-border bg-transparent text-foreground rounded"
          style={{ fontSize: 13, padding: '8px 10px', outline: 'none', fontFamily: 'inherit' }}
          data-testid="settings-update-channel"
        >
          <option value="stable">Stable</option>
          <option value="canary">Canary (pre-release)</option>
        </select>
      </div>

      <div style={{ height: 1, background: 'var(--border)' }} />

      <div>
        <div style={{ fontSize: 13, fontWeight: 600, color: 'var(--foreground)', marginBottom: 4 }}>Privacy &amp; Telemetry</div>
        <div style={{ fontSize: 12, color: 'var(--muted-foreground)', lineHeight: 1.5 }}>
          Anonymous data helps us fix bugs and improve Laputa. No vault content, note titles, or file paths are ever sent.
        </div>
      </div>

      <TelemetryToggle label="Crash reporting" description="Send anonymous error reports" checked={props.crashReporting} onChange={props.setCrashReporting} testId="settings-crash-reporting" />
      <TelemetryToggle label="Usage analytics" description="Share anonymous usage patterns" checked={props.analytics} onChange={props.setAnalytics} testId="settings-analytics" />
    </div>
  )
}

function TelemetryToggle({ label, description, checked, onChange, testId }: { label: string; description: string; checked: boolean; onChange: (v: boolean) => void; testId: string }) {
  return (
    <label style={{ display: 'flex', alignItems: 'center', gap: 10, cursor: 'pointer' }} data-testid={testId}>
      <input type="checkbox" checked={checked} onChange={(e) => onChange(e.target.checked)} style={{ width: 16, height: 16, accentColor: 'var(--primary)' }} />
      <div>
        <div style={{ fontSize: 13, fontWeight: 500, color: 'var(--foreground)' }}>{label}</div>
        <div style={{ fontSize: 11, color: 'var(--muted-foreground)' }}>{description}</div>
      </div>
    </label>
  )
}

function SettingsFooter({ onClose, onSave }: { onClose: () => void; onSave: () => void }) {
  return (
    <div
      className="flex items-center justify-between shrink-0"
      style={{ height: 56, padding: '0 24px', borderTop: '1px solid var(--border)' }}
    >
      <span style={{ fontSize: 11, color: 'var(--muted-foreground)' }}>{'\u2318'}, to open settings</span>
      <div className="flex gap-2">
        <button
          className="border border-border bg-transparent text-foreground rounded cursor-pointer hover:bg-accent"
          style={{ fontSize: 13, padding: '6px 16px' }}
          onClick={onClose}
        >
          Cancel
        </button>
        <button
          className="border-none rounded cursor-pointer"
          style={{ fontSize: 13, padding: '6px 16px', background: 'var(--primary)', color: 'white' }}
          onClick={onSave}
          data-testid="settings-save"
        >
          Save
        </button>
      </div>
    </div>
  )
}