/**
 * @contemporary-props/ceramic-vase
 *
 * First object in the kit, and it is here to settle the revolve.
 *
 * Almost everything with a round section that follows depends on the same
 * profile machinery: the mug, the pepper mill, the stockpot, the basin, the
 * bollard, the traffic cone, every knob, foot and column. So the vase is built
 * as a curve rather than as a shape. Four control heights carry it, and each
 * one is named after what it does to the silhouette:
 *
 *   foot      where it meets the table, narrower than the belly so the vase
 *             looks placed rather than poured
 *   belly     the widest point, and the parameter that decides whether this is
 *             a bud vase or an urn
 *   shoulder  where the wall turns back in, and the one place a generated
 *             vessel usually goes wrong: put it too high and the profile reads
 *             as a bottle, too low and it reads as a bowl
 *   lip       the mouth, rolled slightly proud of the neck so the rim catches
 *             light and the opening does not look like a hole cut in a solid
 *
 * The wall HAS thickness, and the note that used to be here saying it did not
 * was wrong in a way worth keeping written down. It said a vase is looked at
 * from outside and the inside of the neck is dark at every angle a prop is
 * seen from, so modelling the bore
 * would spend triangles on something nothing ever sees. The rim reads because
 * the lip steps out, not because there is a wall behind it. Every clause of
 * that was true and the conclusion did not follow: the mouth is over half the
 * belly across, so anything above the vase looks INTO it, finds the far wall's
 * inside, and a one-sided surface has no inside. It is back-facing, it is
 * culled, and the vase loses its back wall entirely. Reported as "the front
 * shows and the back is cut off, as if it disappears", which is exactly what
 * a culled back face looks like.
 *
 * Parts: `body` alone. There is nothing here that moves or that a consumer
 * would want to reach separately, and inventing parts to look thorough makes
 * the protocol noisier without making the model more useful.
 */
import { type BufferGeometry } from 'three'

import {
  createKitModel,
  createTinter,
  jitter,
  latheGeometry,
  mergeColoured,
  smoothNormals,
  type Level,
} from '../core/index.ts'

export interface CeramicVaseConfig {
  /** Overall height (metres). */
  readonly height: number
  /** Widest radius, at the belly (metres). */
  readonly bellyRadius: number
  /** Where the belly sits, as a fraction of the height. */
  readonly bellyAt: number
  /** Mouth radius as a fraction of the belly radius. */
  readonly mouth: number
  /** Sides around the revolve. Low values are a deliberate faceted look. */
  readonly segments: number
  readonly seed: number
}

export const ceramicVaseDefaults: CeramicVaseConfig = {
  height: 0.32,
  bellyRadius: 0.105,
  // Just below the middle. A belly at or above half height reads as a bottle,
  // and this is the single number that decides whether the silhouette is right.
  bellyAt: 0.42,
  mouth: 0.52,
  segments: 32,
  seed: 11,
}

export type CeramicVaseParts = 'body'

export function createModel(overrides: Partial<CeramicVaseConfig> = {}) {
  return createKitModel<CeramicVaseConfig, 'ceramic', CeramicVaseParts>({
    id: 'ceramic-vase',
    defaults: ceramicVaseDefaults,
    slots: ['ceramic'],

    build: ({ config, random }) => {
      const tint = createTinter(random)
      const H = config.height
      const belly = config.bellyRadius
      const bellyY = H * Math.min(0.72, Math.max(0.18, config.bellyAt))
      const mouth = belly * Math.min(0.9, Math.max(0.2, config.mouth))

      // The foot is a fraction of the belly rather than a free parameter: a
      // vase whose base can be set independently can be given a base wider
      // than its body, and there is no value of that which looks like a vase.
      const foot = belly * 0.62
      const shoulderY = bellyY + (H - bellyY) * 0.58
      const neck = mouth * 1.04

      /**
       * The wall, which this vase did not have.
       *
       * It was one surface with no thickness and no bore, on the argument that
       * the inside of the neck is dark from every angle a prop is seen at. It
       * is not: the mouth is over half the belly across, so anything looking
       * down at the vase looks into it, and what is in there is the INSIDE of
       * the far wall. A single-sided surface has no inside. The far wall is
       * back-facing, it is culled, and the vase is see-through from the one
       * angle everybody eventually tries.
       *
       * So the profile goes up the outside, over the rim and back down the
       * bore to a floor, which is what the mug in this kit already does. It
       * costs about four hundred triangles and it is not optional.
       */
      const wall = Math.max(0.0035, belly * 0.055)
      const floorY = H * 0.07

      const levels: Level[] = [
        { y: 0, radius: foot * 0.94 },
        // A short straight rise off the table before the curve starts. Without
        // it the profile leaves the ground at an angle and the vase looks like
        // it is sinking into the surface.
        { y: H * 0.035, radius: foot },
        { y: bellyY * 0.55, radius: belly * 0.93 },
        { y: bellyY, radius: belly },
        { y: shoulderY, radius: belly * 0.74 },
        { y: H * 0.93, radius: neck },
        // The lip: proud of the neck by a hair, so the mouth has an edge to
        // catch light rather than being a hole in the top.
        { y: H * 0.97, radius: neck * 1.09 },
        { y: H, radius: neck * 1.06 },
        // Over the rim. Rolled rather than turned square, so the mouth reads
        // as a thrown edge and not as sheet cut with scissors.
        { y: H - wall * 0.25, radius: neck * 1.06 - wall * 0.42 },
        { y: H - wall * 0.6, radius: neck * 1.06 - wall },
        // Down the bore, the outside's own profile one wall in, so the wall
        // reads an even thickness from any angle that sees into it.
        { y: H * 0.93, radius: neck - wall },
        { y: shoulderY, radius: belly * 0.74 - wall },
        { y: bellyY, radius: belly - wall },
        { y: bellyY * 0.55, radius: belly * 0.93 - wall },
        // The floor sits above the foot, because a vase is thickest where it
        // takes the weight.
        { y: floorY, radius: foot * 0.72 },
      ]

      const pieces: BufferGeometry[] = [
        latheGeometry(
          levels,
          Math.max(8, Math.round(config.segments)),
          [0, 0, 0],
          tint('ceramic', jitter(random, 0.02)),
          // Glaze pools slightly toward the foot and thins over the shoulder,
          // so the top is a touch lighter. It is a small difference and it is
          // what stops a single-slot object reading as flat plastic.
          { colourTop: tint('ceramic', 0.05), capBottom: true, capTop: true },
        ),
      ]

      // Smoothed at 40 degrees. The wall is a curve and reads as one; the
      // lip, the foot and the base cap all turn through more than that and
      // stay as edges. Flat shading put a visible band at every level of the
      // profile, which on a glazed white surface is the first thing you see.
      return {
        body: { slot: 'ceramic' as const, geometry: smoothNormals(mergeColoured(pieces), 40) },
      }
    },
  }, overrides)
}