'use client'

import type { FloorplanPalette } from '@pascal-app/core'
import { createContext, type ReactNode, useContext, useMemo } from 'react'

/**
 * Per-frame render context shared between the legacy `floorplan-panel.tsx`
 * and the registry-driven `<FloorplanRegistryLayer>`.
 *
 * The legacy panel is the authoritative owner of the floor-plan SVG —
 * it computes `unitsPerPixel` from the viewBox / surface size, mounts the
 * pan/zoom `<g>`, and knows the active theme. The registry layer is mounted
 * inside the same `<g>`, so anything it draws shares the same coordinate
 * system; this context plumbs through the bits it can't recompute on its
 * own without re-implementing the legacy's resize / theme logic.
 *
 * Once `floorplan-panel.tsx` is fully migrated (Phase 6), this provider
 * moves into a kind-agnostic 2D editor shell and the context loses the
 * "legacy bridge" connotation.
 */
export type FloorplanRenderContextValue = {
  /** SVG units per screen pixel — used to keep handle radii consistent at any zoom. */
  unitsPerPixel: number
  /** Themed palette mirroring the legacy `FloorplanPalette` accent slots. */
  palette: FloorplanPalette
  /** SVG `<pattern>` id mounted in `<defs>` by the legacy panel for selection hatch fills. */
  hatchPatternId: string
}

const FloorplanRenderContext = createContext<FloorplanRenderContextValue | null>(null)

export function FloorplanRenderProvider({
  children,
  unitsPerPixel,
  palette,
  hatchPatternId,
}: FloorplanRenderContextValue & { children: ReactNode }) {
  const value = useMemo<FloorplanRenderContextValue>(
    () => ({ unitsPerPixel, palette, hatchPatternId }),
    [unitsPerPixel, palette, hatchPatternId],
  )
  return <FloorplanRenderContext.Provider value={value}>{children}</FloorplanRenderContext.Provider>
}

/**
 * Read the active render context. Returns `null` when called outside a
 * provider — the registry layer treats this as "render statically, skip
 * theme-aware chrome and interactive handles". This makes the layer
 * usable in isolation tests + future editor shells without bringing the
 * whole legacy panel along.
 */
export function useFloorplanRender(): FloorplanRenderContextValue | null {
  return useContext(FloorplanRenderContext)
}