import React, { useState } from 'react'
import { useTheme } from '@/shared/hooks/useTheme'
import { Button } from '@/shared/components/ui/button'
import { Badge } from '@/shared/components/ui/badge'
import { Input } from '@/shared/components/ui/input'
import { Label } from '@/shared/components/ui/label'
import { Separator } from '@/shared/components/ui/separator'
import { Progress } from '@/shared/components/ui/progress'
import {
  Avatar,
  AvatarFallback,
  AvatarImage,
  AvatarGroup,
  AvatarGroupCount,
} from '@/shared/components/ui/avatar'
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
  DialogTrigger,
} from '@/shared/components/ui/dialog'

// ─── palette data — DA Charcoal ──────────────────────────────────────────────

interface PaletteEntry {
  token: string
  cssVar: string
  dark: string
  light: string
  group: 'Invariants' | 'Dark default' | 'Light override'
}

const PALETTE: PaletteEntry[] = [
  // Invariants
  {
    token: 'sidebar-bg',
    cssVar: '--color-sidebar-bg',
    dark: '#0C1528',
    light: '#0C1528',
    group: 'Invariants',
  },
  {
    token: 'brand',
    cssVar: '--color-brand',
    dark: '#1B4FD8',
    light: '#1B4FD8',
    group: 'Invariants',
  },
  {
    token: 'brand-hover',
    cssVar: '--color-brand-hover',
    dark: '#1744B8',
    light: '#1744B8',
    group: 'Invariants',
  },
  {
    token: 'brand-active',
    cssVar: '--color-brand-active',
    dark: '#13379C',
    light: '#13379C',
    group: 'Invariants',
  },
  {
    token: 'warning',
    cssVar: '--color-warning',
    dark: '#F59E0B',
    light: '#F59E0B',
    group: 'Invariants',
  },
  {
    token: 'danger',
    cssVar: '--color-danger',
    dark: '#EF4444',
    light: '#EF4444',
    group: 'Invariants',
  },
  // Dual-theme (valeurs différentes dark/light)
  {
    token: 'canvas',
    cssVar: '--color-canvas',
    dark: '#111111',
    light: '#F3F4F6',
    group: 'Dark default',
  },
  {
    token: 'surface',
    cssVar: '--color-surface',
    dark: 'rgba(255,255,255,.035)',
    light: '#FFFFFF',
    group: 'Dark default',
  },
  {
    token: 'surface-hover',
    cssVar: '--color-surface-hover',
    dark: 'rgba(255,255,255,.055)',
    light: '#F8F9FB',
    group: 'Dark default',
  },
  {
    token: 'surface-solid',
    cssVar: '--color-surface-solid',
    dark: '#1E1E1E',
    light: '#FFFFFF',
    group: 'Dark default',
  },
  {
    token: 'surface-raised',
    cssVar: '--color-surface-raised',
    dark: '#222222',
    light: '#FFFFFF',
    group: 'Dark default',
  },
  {
    token: 'border',
    cssVar: '--color-border',
    dark: 'rgba(255,255,255,.06)',
    light: 'rgba(0,0,0,.07)',
    group: 'Dark default',
  },
  {
    token: 'border-strong',
    cssVar: '--color-border-strong',
    dark: 'rgba(255,255,255,.12)',
    light: 'rgba(0,0,0,.14)',
    group: 'Dark default',
  },
  {
    token: 'ink-primary',
    cssVar: '--color-ink-primary',
    dark: '#E5E5E5',
    light: '#0F0F1A',
    group: 'Dark default',
  },
  {
    token: 'ink-secondary',
    cssVar: '--color-ink-secondary',
    dark: 'rgba(255,255,255,.55)',
    light: 'rgba(0,0,0,.55)',
    group: 'Dark default',
  },
  {
    token: 'ink-tertiary',
    cssVar: '--color-ink-tertiary',
    dark: 'rgba(255,255,255,.3)',
    light: 'rgba(0,0,0,.3)',
    group: 'Dark default',
  },
  {
    token: 'brand-soft',
    cssVar: '--color-brand-soft',
    dark: 'rgba(27,79,216,.1)',
    light: 'rgba(27,79,216,.06)',
    group: 'Dark default',
  },
  {
    token: 'brand-text',
    cssVar: '--color-brand-text',
    dark: '#7DA4F0',
    light: '#1B4FD8',
    group: 'Dark default',
  },
  {
    token: 'success',
    cssVar: '--color-success',
    dark: '#4ADE80',
    light: '#16A34A',
    group: 'Dark default',
  },
  {
    token: 'success-soft',
    cssVar: '--color-success-soft',
    dark: 'rgba(74,222,128,.12)',
    light: 'rgba(22,163,74,.1)',
    group: 'Dark default',
  },
  {
    token: 'warning-soft',
    cssVar: '--color-warning-soft',
    dark: 'rgba(245,158,11,.12)',
    light: 'rgba(245,158,11,.12)',
    group: 'Dark default',
  },
  {
    token: 'danger-soft',
    cssVar: '--color-danger-soft',
    dark: 'rgba(239,68,68,.12)',
    light: 'rgba(239,68,68,.12)',
    group: 'Dark default',
  },
]

// ─── section wrapper ─────────────────────────────────────────────────────────

function Section({ title, children }: { title: string; children: React.ReactNode }) {
  return (
    <section className="space-y-4">
      <h2 className="text-base font-semibold uppercase tracking-wider text-ink-secondary">
        {title}
      </h2>
      <Separator />
      {children}
    </section>
  )
}

// ─── main page ───────────────────────────────────────────────────────────────

export default function DesignSystemPage() {
  const { theme, setTheme } = useTheme()
  const [dialogOpen, setDialogOpen] = useState(false)

  return (
    <div className="min-h-screen space-y-14 bg-canvas px-6 py-10">
      {/* ── header ── */}
      <header className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-bold text-ink-primary">Design System</h1>
          <p className="mt-0.5 text-sm text-ink-secondary">
            Expria — DA Charcoal · dark-default + light override
          </p>
        </div>
        <Button
          variant="outline"
          size="sm"
          onClick={() => setTheme(theme === 'dark' ? 'light' : 'dark')}
        >
          {theme === 'dark' ? 'Light mode' : 'Dark mode'}
        </Button>
      </header>

      {/* ── palette ── */}
      <Section title="Palette">
        <div className="grid grid-cols-2 gap-3 sm:grid-cols-3 lg:grid-cols-4">
          {PALETTE.map(({ token, cssVar, light, dark }) => (
            <div key={token} className="flex flex-col gap-1.5">
              <div
                className="h-12 w-full rounded-md border border-border shadow-card"
                style={{ background: `var(${cssVar})` }}
              />
              <div className="space-y-0.5">
                <p className="font-mono text-xs font-medium text-ink-primary">{token}</p>
                <p className="font-mono text-xs leading-tight text-ink-secondary">☾ {dark}</p>
                <p className="font-mono text-xs leading-tight text-ink-secondary">☀ {light}</p>
              </div>
            </div>
          ))}
        </div>
      </Section>

      {/* ── typography ── */}
      <Section title="Typography">
        <div className="space-y-3 rounded-lg border border-border bg-surface p-6">
          <p className="text-4xl font-bold text-ink-primary">Display / 40px Bold</p>
          <p className="text-2xl font-semibold text-ink-primary">Heading 1 / 24px Semibold</p>
          <p className="text-xl font-semibold text-ink-primary">Heading 2 / 20px Semibold</p>
          <p className="text-lg font-medium text-ink-primary">Heading 3 / 17px Medium</p>
          <p className="text-base text-ink-primary">Body / 14px Regular — Plus Jakarta Sans</p>
          <p className="text-sm text-ink-secondary">Small / 13px Regular — secondary copy</p>
          <p className="text-xs text-ink-tertiary">Caption / 11px Regular — labels, metadata</p>
          <p className="font-mono text-xs text-ink-secondary">Mono / 11px — token names, code</p>
        </div>
      </Section>

      {/* ── buttons ── */}
      <Section title="Button">
        <div className="space-y-4 rounded-lg border border-border bg-surface p-6">
          <div className="flex flex-wrap items-center gap-2">
            <Button>Default</Button>
            <Button variant="secondary">Secondary</Button>
            <Button variant="outline">Outline</Button>
            <Button variant="ghost">Ghost</Button>
            <Button variant="destructive">Destructive</Button>
            <Button variant="link">Link</Button>
          </div>
          <div className="flex flex-wrap items-center gap-2">
            <Button size="lg">Large</Button>
            <Button>Default</Button>
            <Button size="sm">Small</Button>
            <Button size="icon">+</Button>
          </div>
          <div className="flex flex-wrap items-center gap-2">
            <Button disabled>Disabled</Button>
            <Button variant="outline" disabled>
              Outline disabled
            </Button>
          </div>
        </div>
      </Section>

      {/* ── badges ── */}
      <Section title="Badge">
        <div className="flex flex-wrap gap-2 rounded-lg border border-border bg-surface p-6">
          <Badge>Default</Badge>
          <Badge variant="secondary">Secondary</Badge>
          <Badge variant="outline">Outline</Badge>
          <Badge variant="destructive">Destructive</Badge>
        </div>
      </Section>

      {/* ── inputs / forms ── */}
      <Section title="Input · Label · Progress · Separator">
        <div className="max-w-md space-y-5 rounded-lg border border-border bg-surface p-6">
          <div className="space-y-1.5">
            <Label htmlFor="ds-email">Email</Label>
            <Input id="ds-email" type="email" placeholder="you@expria.io" />
          </div>
          <div className="space-y-1.5">
            <Label htmlFor="ds-pass">Password</Label>
            <Input id="ds-pass" type="password" placeholder="••••••••" />
          </div>
          <div className="space-y-1.5">
            <Label htmlFor="ds-invalid">Invalid field</Label>
            <Input id="ds-invalid" aria-invalid="true" placeholder="Error state" />
          </div>
          <div className="space-y-1.5">
            <Label>Progress — 65%</Label>
            <Progress value={65} />
          </div>
          <Separator />
          <p className="text-sm text-ink-secondary">Content below separator</p>
        </div>
      </Section>

      {/* ── avatar ── */}
      <Section title="Avatar">
        <div className="flex flex-wrap items-end gap-6 rounded-lg border border-border bg-surface p-6">
          <div className="flex flex-col items-center gap-2">
            <Avatar size="sm">
              <AvatarImage src="" />
              <AvatarFallback>HK</AvatarFallback>
            </Avatar>
            <span className="text-xs text-ink-secondary">sm</span>
          </div>
          <div className="flex flex-col items-center gap-2">
            <Avatar>
              <AvatarImage src="" />
              <AvatarFallback>HK</AvatarFallback>
            </Avatar>
            <span className="text-xs text-ink-secondary">default</span>
          </div>
          <div className="flex flex-col items-center gap-2">
            <Avatar size="lg">
              <AvatarImage src="" />
              <AvatarFallback>HK</AvatarFallback>
            </Avatar>
            <span className="text-xs text-ink-secondary">lg</span>
          </div>
          <div className="flex flex-col items-center gap-2">
            <AvatarGroup>
              {['AB', 'CD', 'EF'].map((initials) => (
                <Avatar key={initials}>
                  <AvatarFallback>{initials}</AvatarFallback>
                </Avatar>
              ))}
              <AvatarGroupCount>+5</AvatarGroupCount>
            </AvatarGroup>
            <span className="text-xs text-ink-secondary">group</span>
          </div>
        </div>
      </Section>

      {/* ── dialog ── */}
      <Section title="Dialog">
        <div className="rounded-lg border border-border bg-surface p-6">
          <Dialog open={dialogOpen} onOpenChange={setDialogOpen}>
            <DialogTrigger asChild>
              <Button variant="outline">Open dialog</Button>
            </DialogTrigger>
            <DialogContent>
              <DialogHeader>
                <DialogTitle>Example dialog</DialogTitle>
                <DialogDescription>
                  This dialog uses DA Charcoal tokens — bg-surface-solid, border-border,
                  text-ink-secondary. Toggle the theme to see it adapt.
                </DialogDescription>
              </DialogHeader>
              <DialogFooter showCloseButton>
                <Button onClick={() => setDialogOpen(false)}>Confirm</Button>
              </DialogFooter>
            </DialogContent>
          </Dialog>
        </div>
      </Section>
    </div>
  )
}