import { CanvasTextMetrics, Graphics, Rectangle, Text } from 'pixi.js';
import {
  asNumber,
  asString,
  edgesInto,
  type Graph,
  type GraphNode,
  inlineInputDef,
  inlineInputs,
  inlineValue,
  type NodeCategory,
  type NodeDef,
  nodeDef,
  type PortDef,
  type PortType,
  type Value,
} from '../../core/graph';
import { layerIndexOf, layerMaskOf, layerName, maskLabel } from '../../core/model/collisionLayers';
import type { Project } from '../../core/model/Project';
import { isList, type PropertyValue } from '../../core/model/Properties';
import type { PropertyDef } from '../../core/properties/PropertySchema';
import { formatNumber, Theme, textStyle, type TextStyleToken, toHex, truncate, Widget } from '../../ui';
import { keyLabel, referenceLabel } from '../inspector/fieldFactory';
import { collapsedNodeWidth } from './folding';

/** Node geometry in graph units; exported because edge anchors must land exactly on these ports. */
export const NODE_WIDTH = 176;
export const TITLE_HEIGHT = 24;
const ROW_HEIGHT = 20;
const PORT_RADIUS = 5;
/** Distance (graph units) within which a press counts as hitting a port. */
const PORT_HIT_RADIUS = 9;
const PAD = 6;
/** Room in front of the title for the collapse chevron, as wide as the hierarchy's. */
const CHEVRON_SLOT = 14;
const TITLE_X = PAD + CHEVRON_SLOT;
/** Right of a collapsed title: the side's link dot sits centred on the edge. */
const COLLAPSED_TITLE_END = PAD + PORT_RADIUS;

function categoryColor(category: NodeCategory): number {
  const c = Theme.colors;
  switch (category) {
    case 'event':
      return c.categoryEvent;
    case 'flow':
      return c.categoryFlow;
    case 'data':
      return c.categoryData;
    case 'variable':
      return c.categoryVariable;
    case 'action':
      return c.categoryAction;
    case 'state':
      return c.categoryState;
    case 'shader':
      return c.categoryShader;
    case 'particles':
      return c.categoryParticles;
  }
}

export function portColor(type: PortType): number {
  const c = Theme.colors;
  switch (type) {
    case 'exec':
      return c.portExec;
    case 'number':
      return c.portNumber;
    case 'boolean':
      return c.portBoolean;
    case 'string':
      return c.portString;
    case 'object':
      return c.portObject;
    case 'list':
      return c.portList;
    case 'struct':
      return c.portStruct;
    case 'vec3':
      return c.portVec3;
    case 'any':
      return c.portAny;
  }
}

function rowStyle(port: PortDef): TextStyleToken {
  if (port.ghost) return 'warning';
  return port.type === 'exec' ? 'body' : 'muted';
}

export interface PortHit {
  port: PortDef;
  isOutput: boolean;
}

/** Draws one graph node entirely from its NodeDef; positioned in graph coordinates by GraphCanvas. */
export class NodeView extends Widget {
  private readonly box = new Graphics();
  private readonly ports = new Graphics();
  private readonly texts: Text[] = [];
  private paramLines: string[] = [];
  /** Why this node can do nothing; see `callProblem`. */
  private problem: string | null = null;
  selected = false;
  hot = false;
  /** The state a machine begins in wears a ring, so the entry point is visible at a glance. */
  isStart = false;
  /**
   * While something is running: `held` for a state some instance of the machine is in, `current`
   * for the one the selected object's instance holds. Nothing outside a run.
   */
  stateMark: 'none' | 'held' | 'current' = 'none';
  /** Port a running edge drag would connect to, drawn with a ring so the drop is predictable. */
  targetPort: { port: string; isOutput: boolean } | null = null;
  /** Data inputs that currently have a connection (their inline value is hidden). */
  private connected = new Set<string>();
  private inlineTexts = new Map<string, string>();
  /** Which sides carry a link – a collapsed node marks those with one dot each. */
  private linked = { inputs: false, outputs: false };
  private liveTexts = new Map<string, string>();
  private readonly valueTexts = new Map<string, Text>();
  /** Where an output's value may be drawn: right-aligned before its label, clear of the input text. */
  private valueSlots = new Map<string, { left: number; right: number; top: number }>();

  /**
   * Not fixed at construction: a nested-behavior node's ports come from another graph, so the
   * definition that applies to this node can change without the node itself changing.
   */
  def: NodeDef;

  constructor(
    readonly node: GraphNode,
    def: NodeDef,
  ) {
    super();
    this.def = def;
    this.cursor = 'grab';
    this.addChild(this.box, this.ports);
    this.sync(node, { nodes: [node], edges: [] }, null, def);
  }

  /** Ports sit on the left/right edges; widen the hit area so they can be grabbed. */
  override resize(w: number, h: number): void {
    super.resize(w, h);
    this.hitArea = new Rectangle(-PORT_HIT_RADIUS, 0, w + PORT_HIT_RADIUS * 2, h);
  }

  /**
   * Whether a local point is on this node, by the same area its pointer events use. An input port
   * sits at exactly x = 0, and rounding a global point back can land a hair outside it – which made
   * a drop on such a port count as a drop on empty canvas and opened the palette.
   */
  containsLocal(x: number, y: number): boolean {
    return this.hitArea?.contains(x, y) ?? false;
  }

  /** `project` resolves asset references (Spawn, Is asset). */
  sync(
    node: GraphNode,
    graph: Graph,
    project: Project | null,
    def: NodeDef,
    problem: string | null = null,
  ): void {
    this.def = def;
    this.problem = problem;
    const hidden = new Set(this.def.hiddenParams?.(node.params) ?? []);
    const title = this.def.label;
    const derived = title !== nodeDef(node.type)?.label;
    this.paramLines = this.def.params
      .filter((p) => !hidden.has(p.key))
      .map((p) => ({
        label: p.label,
        value: formatParam(p, node.params[p.key] ?? p.default, project),
      }))
      // A title made from a setting states it ("Behavior: Double" under "Double"). A dangling
      // reference keeps its row: "Double?" is not in the title.
      .filter((p) => !derived || (p.value !== title && !title.endsWith(` ${p.value}`)))
      .map((p) => `${p.label}: ${p.value}`);
    this.connected = new Set(
      inlineInputs(this.def)
        .filter((p) => edgesInto(graph, node.id, p.key).length > 0)
        .map((p) => p.key),
    );
    this.inlineTexts = new Map();
    for (const port of inlineInputs(this.def)) {
      const value = inlineValue(node, port);
      if (!this.connected.has(port.key) && value !== null && value !== '')
        this.inlineTexts.set(port.key, formatField(inlineInputDef(port), value, project));
    }
    this.linked = {
      inputs: graph.edges.some((e) => e.to.node === node.id),
      outputs: graph.edges.some((e) => e.from.node === node.id),
    };
    const height = this.collapsed ? TITLE_HEIGHT : this.headerHeight() + this.rowCount() * ROW_HEIGHT + PAD;
    // Sized before the texts: output labels are placed against the right edge.
    this.resize(this.collapsed ? this.collapsedWidth() : NODE_WIDTH, height);
    this.rebuildTexts();
    this.position.set(node.x, node.y);
  }

  private collapsedWidth(): number {
    const title = CanvasTextMetrics.measureText(this.def.label, textStyle('accent')).width;
    return collapsedNodeWidth(title, TITLE_X + COLLAPSED_TITLE_END, NODE_WIDTH);
  }

  get collapsed(): boolean {
    return this.node.collapsed === true;
  }

  chevronAt(localX: number, localY: number): boolean {
    return localY >= 0 && localY < TITLE_HEIGHT && localX >= PAD - 2 && localX < TITLE_X;
  }

  chevronGlobal(): { x: number; y: number } {
    return this.toGlobal({ x: PAD + CHEVRON_SLOT / 2, y: TITLE_HEIGHT / 2 });
  }

  /** Rows of ports, which set the node's height – none on a state, whose ports are never drawn. */
  private rowCount(): number {
    if (this.def.transitionEdges === true) return 0;
    return Math.max(this.def.inputs.length, this.def.outputs.length);
  }

  /** The warning line as drawn – checks read what the node really shows, not a recomputation. */
  get problemText(): string | null {
    return this.problem;
  }

  /** The setting rows as drawn, for the same reason. */
  get settingLines(): string[] {
    return [...this.paramLines];
  }

  get inputLines(): string[] {
    return this.def.inputs.map((input) => this.inputText(input));
  }

  get outputLines(): string[] {
    return this.def.outputs.map((output) => {
      const value = this.valueTexts.get(output.key)?.text;
      return value === undefined ? output.label : `${value}  ${output.label}`;
    });
  }

  /** Nothing clears them when play ends: the views are rebuilt then. */
  setLiveValues(values: Record<string, Value> | null, project: Project | null): void {
    const next = new Map<string, string>();
    for (const output of this.def.outputs) {
      const value = values?.[output.key];
      if (output.type === 'exec' || value === undefined) continue;
      next.set(output.key, formatLive(output, value, project));
    }
    if (next.size === this.liveTexts.size && [...next].every(([k, v]) => this.liveTexts.get(k) === v)) return;
    this.liveTexts = next;
    this.placeValues();
  }

  private placeValues(): void {
    for (const text of this.valueTexts.values()) text.destroy();
    this.valueTexts.clear();
    if (this.collapsed) return;
    const style = textStyle('live');
    for (const [key, value] of this.liveTexts) {
      const slot = this.valueSlots.get(key);
      if (!slot || slot.right - slot.left < 12) continue;
      const text = new Text({ text: truncate(value, style, slot.right - slot.left), style });
      text.position.set(slot.right - text.width, slot.top);
      this.addChild(text);
      this.valueTexts.set(key, text);
    }
  }

  private inputText(input: PortDef): string {
    const inline = this.inlineTexts.get(input.key);
    return inline === undefined ? input.label : `${input.label}  ${inline}`;
  }

  /** Everything above the first port row. The problem line sits in here, so ports move down with it. */
  private headerHeight(): number {
    const lines = this.paramLines.length + (this.problem ? 1 : 0);
    return TITLE_HEIGHT + PAD + lines * ROW_HEIGHT;
  }

  /** Local position of a port's centre. */
  portPosition(key: string, isOutput: boolean): { x: number; y: number } | null {
    const list = isOutput ? this.def.outputs : this.def.inputs;
    const index = list.findIndex((p) => p.key === key);
    if (index < 0) return null;
    return { x: isOutput ? this.w : 0, y: this.collapsed ? TITLE_HEIGHT / 2 : this.rowY(index) };
  }

  private rowY(index: number): number {
    return this.headerHeight() + index * ROW_HEIGHT + ROW_HEIGHT / 2;
  }

  /**
   * Every port with its local centre – none while collapsed, and none on a state, so neither can
   * be drawn or grabbed. `portPosition` stays open either way: the edges still need their anchor.
   */
  private *portCentres(): Iterable<{ port: PortDef; isOutput: boolean; x: number; y: number }> {
    if (this.collapsed || this.def.transitionEdges === true) return;
    for (const [list, isOutput] of [
      [this.def.inputs, false],
      [this.def.outputs, true],
    ] as const) {
      for (let i = 0; i < list.length; i++)
        yield { port: list[i]!, isOutput, x: isOutput ? this.w : 0, y: this.rowY(i) };
    }
  }

  portAt(localX: number, localY: number): PortHit | null {
    for (const { port, isOutput, x, y } of this.portCentres()) {
      if (Math.hypot(localX - x, localY - y) <= PORT_HIT_RADIUS) return { port, isOutput };
    }
    return null;
  }

  private rebuildTexts(): void {
    for (const t of this.texts) t.destroy();
    this.texts.length = 0;
    this.valueSlots = new Map();
    const add = (
      text: string,
      style: TextStyleToken,
      x: number,
      y: number,
      align: 'left' | 'right' = 'left',
      maxWidth = NODE_WIDTH - PAD * 2,
    ) => {
      const node = new Text({ text: truncate(text, textStyle(style), maxWidth), style: textStyle(style) });
      node.position.set(align === 'left' ? x : x - node.width, y);
      this.addChild(node);
      this.texts.push(node);
      return node;
    };
    add(
      this.def.label,
      'accent',
      TITLE_X,
      (TITLE_HEIGHT - 16) / 2,
      'left',
      this.w - TITLE_X - (this.collapsed ? COLLAPSED_TITLE_END : PAD),
    );
    if (this.collapsed) {
      this.placeValues();
      return;
    }
    let y = TITLE_HEIGHT + PAD;
    for (const line of this.paramLines) {
      add(line, 'small', PAD + 2, y + 2);
      y += ROW_HEIGHT;
    }
    if (this.problem) {
      add(this.problem, 'warning', PAD + 2, y + 2);
      y += ROW_HEIGHT;
    }
    for (let i = 0; i < this.rowCount(); i++) {
      const input = this.def.inputs[i];
      const output = this.def.outputs[i];
      const rowTop = y + i * ROW_HEIGHT + 2;
      let inputEnd = PAD;
      if (input) {
        const text = add(
          this.inputText(input),
          rowStyle(input),
          PAD + PORT_RADIUS + 4,
          rowTop,
          'left',
          NODE_WIDTH / 2 + 20,
        );
        inputEnd = text.x + text.width;
      }
      if (output) {
        const text = add(
          output.label,
          rowStyle(output),
          this.w - PAD - PORT_RADIUS - 4,
          rowTop,
          'right',
          NODE_WIDTH / 2 - 10,
        );
        if (output.type !== 'exec' && !output.ghost)
          this.valueSlots.set(output.key, { left: inputEnd + 6, right: text.x - 6, top: rowTop + 1 });
      }
    }
    this.placeValues();
  }

  override redraw(): void {
    const c = Theme.colors;
    this.box.clear();
    this.box.roundRect(2, 3, this.w, this.h, Theme.radius).fill({ color: 0x000000, alpha: 0.35 });
    this.box.roundRect(0, 0, this.w, this.h, Theme.radius).fill(c.node);
    this.box.roundRect(0, 0, this.w, TITLE_HEIGHT, Theme.radius).fill(categoryColor(this.def.category));
    if (!this.collapsed)
      this.box
        .rect(0, TITLE_HEIGHT - Theme.radius, this.w, Theme.radius)
        .fill(categoryColor(this.def.category));
    this.drawChevron(PAD + 4, TITLE_HEIGHT / 2);
    // The ring sits where a state's ports never are: a state draws none (see `portCentres`).
    if (this.isStart)
      this.box
        .circle(this.w - PAD - PORT_RADIUS, TITLE_HEIGHT / 2, PORT_RADIUS)
        .stroke({ width: 2, color: c.text });
    const border = this.hot ? c.hot : this.selected ? c.nodeSelected : this.problem ? c.danger : c.nodeBorder;
    this.box
      .roundRect(0.5, 0.5, this.w - 1, this.h - 1, Theme.radius)
      .stroke({ width: this.selected || this.hot || this.problem ? 2 : 1, color: border });
    // Inside the border, so a selected state still shows both: what is picked, and what is live.
    if (this.stateMark !== 'none')
      this.box
        .roundRect(2.5, 2.5, this.w - 5, this.h - 5, Theme.radius)
        .stroke({ width: 2, color: c.hot, alpha: this.stateMark === 'current' ? 1 : 0.35 });

    this.ports.clear();
    const r = PORT_RADIUS;
    if (this.collapsed) {
      for (const [linked, x] of [
        [this.linked.inputs, 0],
        [this.linked.outputs, this.w],
      ] as const) {
        if (!linked) continue;
        this.ports.circle(x, TITLE_HEIGHT / 2, r - 1).fill(c.textMuted);
        this.ports.circle(x, TITLE_HEIGHT / 2, r - 1).stroke({ width: 1, color: c.node });
      }
    }
    for (const { port, isOutput, x, y } of this.portCentres()) {
      if (this.targetPort?.port === port.key && this.targetPort.isOutput === isOutput) {
        // A gap in the node colour first, so the ring stays visible on the white exec pin too.
        this.ports.circle(x, y, r + 2).stroke({ width: 2, color: c.node });
        this.ports.circle(x, y, r + 4).stroke({ width: 2, color: c.portTarget });
      }
      if (port.ghost) {
        // Hollow: a pin is drawn where a port used to be, and nothing stands behind it any more.
        this.ports.circle(x, y, r).stroke({ width: 2, color: c.danger });
      } else if (port.type === 'exec') {
        // A pentagon pointing right: the Blueprint-style exec pin.
        this.ports
          .moveTo(x - r, y - r)
          .lineTo(x + 1, y - r)
          .lineTo(x + r + 1, y)
          .lineTo(x + 1, y + r)
          .lineTo(x - r, y + r)
          .closePath()
          .fill(portColor('exec'));
      } else {
        // `paintType`: an `any` input takes the colour of the edge feeding it, its type stays `any`.
        this.ports.circle(x, y, r).fill(portColor(port.paintType ?? port.type));
        this.ports.circle(x, y, r).stroke({ width: 1, color: c.node });
      }
    }
  }

  /** The hierarchy's shape, so both folds read the same. */
  private drawChevron(x: number, y: number): void {
    const color = Theme.colors.text;
    if (this.collapsed)
      this.box
        .moveTo(x - 1, y - 4)
        .lineTo(x + 4, y)
        .lineTo(x - 1, y + 4)
        .fill(color);
    else
      this.box
        .moveTo(x - 3, y - 2)
        .lineTo(x + 5, y - 2)
        .lineTo(x + 1, y + 3)
        .fill(color);
  }
}

function formatParam(param: PropertyDef, value: PropertyValue | undefined, project: Project | null): string {
  if (value === undefined || value === '') return '—';
  return formatField(param, value, project);
}

/** A value in the words of the field that edits it: a key's name, a color's hex, a texture's name. */
function formatField(def: PropertyDef, value: Value, project: Project | null): string {
  if (def.kind === 'key') return keyLabel(asString(value));
  if (def.kind === 'color') return toHex(asNumber(value));
  // Layers read as names, not as the bits they are stored in (#152, #158).
  const layers = project?.collisionLayers ?? [];
  if (def.kind === 'layer') return layerName(layers, layerIndexOf(value));
  if (def.kind === 'layers') return maskLabel(layerMaskOf(value), layers);
  if (def.kind === 'enum') return def.options.find((o) => o.value === value)?.label ?? formatValue(value);
  return referenceLabel(def, project, asString(value)) ?? formatValue(value);
}

function formatLive(output: PortDef, value: Value, project: Project | null): string {
  if (value === null) return '—';
  if (value === '') return '""';
  return output.field ? formatField(output.field, value, project) : formatValue(value);
}

function formatValue(value: Value): string {
  if (typeof value === 'number') return formatNumber(value);
  if (typeof value === 'boolean') return value ? 'true' : 'false';
  // A list can hold hundreds of items – shown whole it would stretch the node across the graph.
  if (isList(value)) {
    if (value.length === 0) return 'empty';
    const head = value.slice(0, 4).map(formatValue).join(', ');
    return value.length > 4 ? `${head}, … (${value.length})` : head;
  }
  return asString(value);
}