import { createContext, useCallback, useContext, useId, useLayoutEffect, useMemo, useRef, useState, type ReactNode } from "react"
import { DownloadIcon } from "lucide-react"
import type { Meta, StoryObj } from "@storybook/react-vite"
import { Button, type ButtonAppearance } from "@hm-design/ui"
import { StoryPage, StoryPageHeader, StorySection, StorySectionGrid } from "@/components/story-page"
import { ToggleSections } from "./toggle-examples"

// Story structure follows ui_viz (implementations/web/storybook/Button.stories.jsx):
// one representative "Button" Story shows kinds, sizes and states on a single screen; the same sections also exist
// as separate Stories tagged `verification`, which the sidebar hides by default (see .storybook/main.ts).
// Playground and Compatibility are HM-only and come after the ui_viz Stories.

type Role = "primary" | "secondary" | "modify" | "destructive" | "cancel"

// [role, label]. The gallery shows supported role/treatment combinations; usage sets are documented separately.
const roles: [Role, string][] = [
  ["primary", "Green"],
  ["secondary", "Brown"],
  ["modify", "Orange"],
  ["cancel", "Gray"],
  ["destructive", "Red"],
]
const rolesFor = (appearance: ButtonAppearance) =>
  roles.filter(([role]) =>
    appearance === "brand"
      ? ["primary", "secondary", "modify"].includes(role)
      : appearance === "solid"
        ? true
        : ["primary", "secondary", "destructive", "cancel"].includes(role),
  )

const meta = {
  title: "Components/Form/Button",
  component: Button,
  parameters: {
    layout: "padded",
    docs: {
      description: {
        component:
          "ui_viz docs/components/button.md D-087: Brand Gradient와 Standard Solid/Outline. 크기 28/34/42, 글자 12/18 · 13/20 · 15/22, Brand 700 · Standard 500. Focus 시각 값은 ui_viz에서 전역 TBD이므로 shadcn 기본 focus 동작을 그대로 사용하며, Tab 키로 확인합니다.",
      },
    },
  },
  argTypes: {
    variant: {
      control: "select",
      options: roles.map(([role]) => role),
      description: "역할(Role): primary Green, secondary Brown, modify Orange, destructive Red, cancel Gray. destructive는 solid/outline, modify는 brand/solid만, cancel은 solid/outline만 지원합니다. docs/components/button.md §6.1 참조.",
    },
    appearance: {
      control: "inline-radio",
      options: ["brand", "solid", "outline"],
      description: "Treatment 기본값은 brand. Controls는 Role별 허용 조합을 제한하지 않습니다. destructive/cancel은 허용 appearance를 명시합니다. docs/components/button.md §6.1~6.2 참조.",
    },
    size: {
      control: "inline-radio",
      options: ["sm", "default", "lg"],
      description: "sm은 Small 28px, default는 Medium 34px, lg는 Large 42px.",
    },
    disabled: { control: "boolean" },
    children: { control: "text" },
    asChild: { table: { disable: true } },
    className: { table: { disable: true } },
  },
} satisfies Meta<typeof Button>
export default meta
type Story = StoryObj<typeof meta>

const row = "flex flex-wrap items-center gap-4"
const stack = "grid gap-6"
const heading = "text-base font-bold"
const note = "text-sm text-muted-foreground"

const appearances = [
  ["brand", "Brand"],
  ["solid", "Standard Solid"],
  ["outline", "Standard Outline"],
] as const

function RoleRow({ appearance }: { appearance: (typeof appearances)[number][0] }) {
  return (
    <div className={row}>
      {rolesFor(appearance).map(([variant, label]) => (
        <Button key={variant} variant={variant} appearance={appearance}>
          {label}
        </Button>
      ))}
    </div>
  )
}

function RolesBoard() {
  return (
    <div className={stack}>
      {appearances.map(([appearance, title]) => (
        <section key={appearance}>
          <h3 className={heading}>{title}</h3>
          <div className="mt-3">
            <RoleRow appearance={appearance} />
          </div>
        </section>
      ))}
    </div>
  )
}

const sizes = [
  ["sm", "Small"],
  ["default", "Medium"],
  ["lg", "Large"],
] as const

function SizesBoard() {
  return (
    <div className={stack}>
      {(["brand", "solid"] as const).map((appearance) => (
        <div className={row} key={appearance}>
          {sizes.map(([size, label]) => (
            <Button key={size} appearance={appearance} size={size}>
              {label}
            </Button>
          ))}
        </div>
      ))}
    </div>
  )
}

// Verification "Brand States" (note and Activated readout). The representative page shows Brand states in StateMatrix.
function BrandStates() {
  const [count, setCount] = useState(0)
  return (
    <div className={stack}>
      <div className={row}>
        <Button>Default</Button>
        <Button data-sb-hover="">Hover</Button>
        <Button data-sb-active="">Pressed</Button>
        <Button onClick={() => setCount((n) => n + 1)}>Interact</Button>
        <Button disabled onClick={() => setCount((n) => n + 1)}>
          Disabled
        </Button>
      </div>
      <output aria-live="polite">Activated: {count}</output>
      <p className={note}>
        Hover와 Pressed는 Storybook이 고정한 상태입니다. Interact 위에서 실제 Hover·Pressed·포인터 이탈을 확인합니다. Disabled는 실행되지 않습니다.
      </p>
    </div>
  )
}

const standardStates = [
  ["Default", {}],
  ["Hover", { "data-sb-hover": "" }],
  ["Pressed", { "data-sb-active": "" }],
  ["Disabled", { disabled: true }],
] as const

// Verification "Standard States" table (rows = roles). The representative page uses StateMatrix (rows = states) instead.
function StandardStateTable({ appearance, title }: { appearance: "solid" | "outline"; title?: string }) {
  return (
    <section className="min-w-0">
      {title ? <h3 className={heading}>{title}</h3> : null}
      <div className={`${title ? "mt-3 " : ""}min-w-0 max-w-full overflow-x-auto`}>
        <table className="w-full border-collapse [&_th]:text-left [&_td]:p-3 [&_th]:p-3">
          <thead>
            <tr>
              {title ? <th scope="col">Role</th> : null}
              {standardStates.map(([state]) => (
                <th scope="col" key={state}>
                  {state}
                </th>
              ))}
            </tr>
          </thead>
          <tbody>
            {rolesFor(appearance).map(([variant, label]) => (
              <tr key={variant}>
                {title ? <th scope="row">{label}</th> : null}
                {standardStates.map(([state, props]) => (
                  <td key={state}>
                    <Button variant={variant} appearance={appearance} {...props}>
                      {label}
                    </Button>
                  </td>
                ))}
              </tr>
            ))}
          </tbody>
        </table>
      </div>
    </section>
  )
}

function StandardStatesBoard({ showNote = true }: { showNote?: boolean }) {
  return (
    <div className={stack}>
      <StandardStateTable appearance="solid" title="Standard Solid" />
      <StandardStateTable appearance="outline" title="Standard Outline" />
      {showNote ? (
        <p className={note}>
          Standard Solid의 Hover·Pressed는 역할 면 위에 Black 20%를 합성합니다(Pressed = Hover). Green·Brown Outline은 Hover에서 역할색 면 + White 라벨, Pressed에서 White 면 + Black 20%입니다. Red Outline은 Hover·Pressed 모두 Red 8% 면이며 Red 라벨·보더를 유지합니다. Disabled는 Default 모양 그대로 opacity 60%이고 상태 면을 적용하지 않습니다. Default 열의 버튼으로 실제 포인터 상태도 확인할 수 있습니다. Brand 상태는 Brand States에서 확인합니다.
        </p>
      ) : null}
    </div>
  )
}

function LongLabelBoard() {
  return (
    <div className="w-[180px]">
      <Button className="whitespace-normal">Apply changes to all selected project records</Button>
    </div>
  )
}

function DestructiveBoard() {
  return (
    <div className={row}>
      <Button variant="cancel" appearance="solid">
        Cancel
      </Button>
      <Button variant="destructive" appearance="solid">
        Delete
      </Button>
    </div>
  )
}

// Representative-page layout (2026-11-12 compact comparison). Page and section spacing come from the common Story page
// (story-page.css); only the arrangement below is local. Buttons are rendered with their public API and never restyled.
// Group label: the StateBoard H3 style (14/20/500, secondary). `data-sb-board` gives the block the common one-step section indent.
const groupLabel = "m-0 text-sm font-medium text-muted-foreground"

// 2026-11-13 (user request): one column per treatment, Sizes and States inside it. Each block is its H3 label (StateBoard H3
// style), 8px, then the specimens; Sizes and States are 24px apart. The blocks stay on the section edge (no data-sb-board
// indent) so the 420px Standard Solid matrix fits an equal third at the 1400px breakpoint without an inner scroll.
function GroupBlock({ id, label, children }: { id: string; label: string; children: ReactNode }) {
  return (
    <section data-overview-state={id} aria-label={label} className="grid min-w-0 content-start gap-2">
      <h3 className={groupLabel}>{label}</h3>
      {children}
    </section>
  )
}

// States: one matrix per treatment, rows = Default / Hover / Pressed / Disabled (standardStates, the same 4 rows for Brand;
// the live Interact button stays on the verification "Brand States"), columns = that treatment's colors in the roles order.
// Columns follow their buttons (auto table layout). 4px cell padding gives the same 8px gap as Sizes between buttons, rows,
// the state label and the color header; the outer edge keeps none (pl-0 / last:pr-0). Buttons sit centered under their color
// and are never resized. Matrix widths: Brand 301px, Standard Solid 420px, Standard Outline 338px.
// 2026-11-13 (user request, no inner scroll on narrow screens): when a matrix is wider than its column (the 420px Standard Solid
// matrix in a 358px column at 390px), every treatment switches together to the stacked layout: one row per state, its label
// above the buttons, which wrap with the same 8px gap. Each matrix measures its own table (the auto-layout width it needs) and
// reports whether it fits; MatrixFitProvider stacks all of them while any does not, so the three treatments keep one layout.
// Storybook presentation only: the buttons, their props and states are unchanged.
// Stacked layout state names (2026-11-13, user request): one step below the H3 "States" label (14/20/500) so the two levels
// read apart — 12/16/400, same secondary color. Only these names change; the common H2 / H3 styles are untouched.
const stackedStateLabel = "text-xs font-normal text-muted-foreground"

const MatrixFit = createContext<{ stacked: boolean; report: (id: string, overflow: boolean) => void }>({ stacked: false, report: () => {} })

function MatrixFitProvider({ children }: { children: ReactNode }) {
  const [overflowing, setOverflowing] = useState<ReadonlySet<string>>(() => new Set())
  const report = useCallback((id: string, overflow: boolean) => {
    setOverflowing((current) => {
      if (current.has(id) === overflow) return current
      const next = new Set(current)
      if (overflow) next.add(id)
      else next.delete(id)
      return next
    })
  }, [])
  const value = useMemo(() => ({ stacked: overflowing.size > 0, report }), [overflowing, report])
  return <MatrixFit.Provider value={value}>{children}</MatrixFit.Provider>
}

function StateMatrix({ appearance, states }: { appearance: ButtonAppearance; states: readonly (readonly [string, Record<string, unknown>])[] }) {
  const colors = rolesFor(appearance)
  const { stacked, report } = useContext(MatrixFit)
  const frame = useRef<HTMLDivElement>(null)
  // The table's own width, kept while the stacked layout is shown (no table to measure then).
  const tableWidth = useRef(0)
  const labelId = useId()
  useLayoutEffect(() => {
    const element = frame.current
    if (!element) return
    const check = () => {
      const table = element.querySelector("table")
      if (table) tableWidth.current = table.offsetWidth
      report(appearance, tableWidth.current > element.clientWidth)
    }
    const observer = new ResizeObserver(check)
    observer.observe(element)
    check()
    // The labels may get wider once the web font has loaded.
    void document.fonts?.ready.then(check)
    return () => {
      observer.disconnect()
      report(appearance, false)
    }
  }, [appearance, report])
  if (stacked) {
    return (
      <div ref={frame} data-state-matrix="stacked" className="grid min-w-0 max-w-full gap-3">
        {states.map(([state, props], index) => (
          <div key={state} role="group" aria-labelledby={`${labelId}-${index}`} className="grid gap-1">
            <span id={`${labelId}-${index}`} className={stackedStateLabel}>
              {state}
            </span>
            <div className="flex min-w-0 flex-wrap items-center gap-2">
              {colors.map(([variant, color]) => (
                <Button key={variant} variant={variant} appearance={appearance} {...props}>
                  {color}
                </Button>
              ))}
            </div>
          </div>
        ))}
      </div>
    )
  }
  return (
    <div ref={frame} data-state-matrix="table" className="min-w-0 max-w-full overflow-x-auto">
      <table className="border-collapse">
        <thead>
          <tr>
            <th scope="col" className={`${groupLabel} pb-1 pl-0 pr-1 text-left`}>
              <span className="sr-only">State</span>
            </th>
            {colors.map(([variant, color]) => (
              <th scope="col" key={variant} className={`${groupLabel} px-1 pb-1 text-center last:pr-0`}>
                {color}
              </th>
            ))}
          </tr>
        </thead>
        <tbody>
          {states.map(([state, props]) => (
            <tr key={state}>
              <th scope="row" className={`${groupLabel} py-1 pl-0 pr-1 text-left whitespace-nowrap`}>
                {state}
              </th>
              {colors.map(([variant, color]) => (
                <td key={variant} className="p-1 text-center last:pr-0">
                  <Button variant={variant} appearance={appearance} {...props}>
                    {color}
                  </Button>
                </td>
              ))}
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  )
}

// The Toggle Button section of the representative page, in the same stacked / matrix form as the state matrices.
function ToggleButtonSection() {
  const { stacked } = useContext(MatrixFit)
  return <ToggleSections titlePrefix="Toggle Button" idPrefix="toggle-" flat stacked={stacked} />
}

// Representative Story: the common Story page, one section per treatment (Brand | Standard Solid | Standard Outline).
// The former Overview button was the default Brand Medium button already shown under Sizes, so Overview is merged into Sizes.
// 2026-11-13 (user request): the Variants section and the page-level Sizes / States titles are removed; each treatment section
// (H2, common title → content 12px) holds its own Sizes and States (H3). The verification "Roles" Story keeps the role rows.
// Named after the component, as in ui_viz. It is the only Button entry in the default sidebar, so Storybook shows Button as a single 1-depth item.
export const All: Story = {
  name: "Button",
  parameters: { layout: "fullscreen" },
  render: () => (
    <StoryPage>
      <StoryPageHeader title="Button" />
      {/* Equal-width columns from a 1400px preview (the 420px Standard Solid matrix fits a third: 3 × 420 + 2 × 24 plus the page
          margins and the scrollbar); below that Brand → Standard Solid → Standard Outline in one column, 28px apart (the
          common section gap of StorySectionGrid). */}
      <MatrixFitProvider>
        <StorySectionGrid className="grid-cols-1 items-start min-[1400px]:grid-cols-3">
          {appearances.map(([appearance, label]) => (
            <StorySection key={appearance} id={`${appearance}-group`} title={label}>
              <div className="grid min-w-0 gap-6">
                <GroupBlock id={`sizes-${appearance}`} label="Sizes">
                  <div className="flex min-w-0 flex-wrap items-center gap-2">
                    {sizes.map(([size, sizeLabel]) => (
                      <Button key={size} appearance={appearance} size={size}>
                        {sizeLabel}
                      </Button>
                    ))}
                  </div>
                </GroupBlock>
                <GroupBlock id={`${appearance}-states`} label="States">
                  <StateMatrix appearance={appearance} states={standardStates} />
                </GroupBlock>
              </div>
            </StorySection>
          ))}
        </StorySectionGrid>
        {/* 2026-11-13 (user request): Toggle Button joins the Button page ("버튼") after the treatment columns, from
            ./toggle-examples unchanged; the Toggle Stories keep their IDs and direct URLs but are hidden from the sidebar.
            `flat`: one "Toggle Button" H2 section, 36px below the columns above, with 3 equal group columns (Variants / States,
            Groups, Sizes) from 1400px like the treatments, each row in the States matrix form (label left, 8px rhythm).
            Inside MatrixFitProvider so its rows switch to the stacked form together with the matrices. */}
        <ToggleButtonSection />
      </MatrixFitProvider>
    </StoryPage>
  ),
}

// Verification Stories: the same sections as separate Stories, hidden from the sidebar (tag `verification`), reachable by URL or the sidebar tag filter.
export const Roles: Story = { tags: ["verification"], render: () => <RolesBoard /> }
export const Sizes: Story = { tags: ["verification"], render: () => <SizesBoard /> }
export const States: Story = { tags: ["verification"], name: "Brand States", render: () => <BrandStates /> }
export const StandardStates: Story = { tags: ["verification"], name: "Standard States", render: () => <StandardStatesBoard /> }
export const LongLabel: Story = {
  tags: ["verification"],
  render: () => <LongLabelBoard />,
  parameters: {
    docs: { description: { story: "일반 Label은 한 줄입니다. 긴 Label은 기존 className API의 whitespace-normal로 줄바꿈을 명시하며, 폭이 부족하면 높이가 늘어나고 각 줄은 가운데 정렬됩니다." } },
  },
}

export const KoreanLabels: Story = {
  tags: ["verification"],
  render: () => (
    <div style={{ display: "grid", gap: 16, width: 88 }}>
      {["저장", "변경사항 적용", "설정 저장", "파일 다운로드"].map((label) => <div key={label}><Button>{label}</Button></div>)}
    </div>
  ),
}
export const IconTextNarrow: Story = {
  tags: ["verification"],
  render: () => (
    <div style={{ display: "grid", gap: 16, width: 88 }}>
      {(["sm", "default", "lg"] as const).map((size) => <div key={size}><Button size={size}><DownloadIcon />파일 다운로드</Button></div>)}
    </div>
  ),
}
export const Destructive: Story = {
  tags: ["verification"],
  render: () => <DestructiveBoard />,
  parameters: {
    docs: { description: { story: "검증 전용 삭제·취소 세트: Cancel은 Gray Solid, Delete는 Red Solid이며 appearance와 size를 통일합니다. Solid Hover/Pressed는 기존 Black 20% overlay이며 Red 토큰을 사용합니다." } },
  },
}

// HM only: not part of the ui_viz Button Stories. Tagged verification so the default sidebar keeps only the representative Story.
export const Playground: Story = {
  tags: ["verification"],
  args: { children: "저장", variant: "primary", appearance: "brand", size: "default", disabled: false },
  parameters: {
    docs: { description: { story: "검증 전용 Controls는 역할과 Treatment를 독립적으로 선택하므로 미지원 조합도 선택할 수 있습니다. 대표 Button의 Variants와 docs/components/button.md §6.1의 허용 조합만 사용하세요. Focus는 ui_viz에서 TBD이므로 Tab 키로 shadcn 기본 focus 동작을 확인합니다." } },
  },
}

export const Compatibility: Story = {
  tags: ["verification"],
  render: () => (
    <div className={stack}>
      <section>
        <h2 className={heading}>shadcn compatibility</h2>
        <p className={`${note} mt-1`}>ui_viz 공식 Button 규격이 아닙니다. shadcn 기본 스타일을 그대로 씁니다.</p>
        <div className={`${row} mt-3`}>
          <Button variant="ghost">ghost</Button>
          <Button variant="link">link</Button>
        </div>
      </section>
      <section>
        <h2 className={heading}>alias</h2>
        <p className={`${note} mt-1`}>기존 shadcn 사용 코드를 위한 별칭입니다. default는 primary, outline은 primary + outline과 같습니다.</p>
        <div className={`${row} mt-3`}>
          <Button variant="default">default</Button>
          <Button variant="outline">outline</Button>
        </div>
      </section>
    </div>
  ),
}