import { textOf } from '../model/Properties';
import { isTaggedKind } from '../properties/kinds';
import { flatDef, isValidFieldName } from '../properties/PropertySchema';
import { type DeclaredPort, declaredPortType, type Graph, type GraphNode } from './Graph';
import type { GraphLookup } from './lookup';
import { nodeDef, type NodeDef, type PortDef } from './NodeRegistry';

export const BEHAVIOR_START = 'BehaviorStart';
export const BEHAVIOR_END = 'BehaviorEnd';
export const RUN_BEHAVIOR = 'RunBehavior';
export const VARIABLES = 'Variables';
export const PROPERTIES = 'Properties';

export const BEHAVIOR_PARAM = 'behavior';

/**
 * Nodes whose declared ports are not names of their own but variables of the behavior around them.
 * Renaming a variable therefore has to reach them, and the inspector picks their ports from a list
 * instead of letting them be typed.
 */
export function declaresVariablePorts(type: string): boolean {
  return type === VARIABLES;
}

/** Nodes whose declared ports are properties of the object they are handed. */
export function declaresPropertyPorts(type: string): boolean {
  return type === PROPERTIES;
}

/** Identifier-like, and not `exec`: that key belongs to the fixed flow port of every terminal node. */
export function isValidPortName(name: string): boolean {
  return isValidFieldName(name) && name !== 'exec';
}

/**
 * Keys a declared port cannot take: the node's fixed ports on the side it declares (`object`), and
 * its settings, which share the params bag with the typed-in values of its inputs.
 */
export function fixedPortKeys(def: NodeDef): string[] {
  const side = def.declaresPorts;
  const fixed =
    side === 'inputs' ? def.inputs : side === 'outputs' ? def.outputs : [...def.inputs, ...def.outputs];
  return [...fixed.map((p) => p.key), ...def.params.map((p) => p.key)];
}

export function declaredOn(
  def: NodeDef,
  ports: readonly DeclaredPort[],
  side: 'inputs' | 'outputs',
): DeclaredPort[] {
  if (def.declaresPorts === 'both') return side === 'outputs' ? [...ports] : ports.filter((p) => p.write);
  return def.declaresPorts === side ? [...ports] : [];
}

/** What a collapsed Variables or Properties node does, since its ports are out of sight. */
export function collapsedTitle(ports: readonly DeclaredPort[], noun: string): string {
  const set = ports.filter((p) => p.write);
  const get = ports.filter((p) => !p.write);
  if (set.length > 1) return `Set ${set.length} ${noun}`;
  if (get.length > 1) return `Get ${get.length} ${noun}`;
  if (set[0]) return `Set ${set[0].key}`;
  if (get[0]) return `Get ${get[0].key}`;
  return `No ${noun}`;
}

/** The single start (or end) node of a graph; a second one is ignored. */
export function terminalNode(graph: Graph, type: string): GraphNode | undefined {
  return graph.nodes.find((n) => n.type === type);
}

export function isTerminalType(type: string): boolean {
  return type === BEHAVIOR_START || type === BEHAVIOR_END;
}

export function isTerminalNode(node: GraphNode): boolean {
  return isTerminalType(node.type);
}

/** A tagged kind is one the value cannot show, so its port carries the field that edits it. */
export function portDefOf(port: DeclaredPort): PortDef {
  const def: PortDef = { key: port.key, label: port.key, type: declaredPortType(port.kind) };
  return isTaggedKind(port.kind) ? { ...def, field: flatDef(port.key, port.kind) } : def;
}

/** The ports the start (or end) node of `graph` declares, as seen from a node calling it. */
export function declaredPorts(graph: Graph | undefined, type: string): PortDef[] {
  const node = graph && terminalNode(graph, type);
  return (node?.ports ?? []).map(portDefOf);
}

/**
 * The node definition as it applies to *this* node: identical to the registered one, unless the
 * type declares ports per node (`declaresPorts`) or computes them (`derivePorts`).
 */
export function resolveDef(node: GraphNode, graph: Graph, lookup: GraphLookup): NodeDef | undefined {
  const def = nodeDef(node.type);
  if (!def || (!def.declaresPorts && !def.derivePorts)) return def;
  const own = (side: 'inputs' | 'outputs') =>
    declaredOn(def, node.ports ?? [], side).map((p) =>
      def.declaredPort ? def.declaredPort(p, node) : portDefOf(p),
    );
  const grown = def.derivePorts?.({ node, graph, lookup }) ?? {};
  const side = (key: 'inputs' | 'outputs') => execFirst([...def[key], ...(grown[key] ?? []), ...own(key)]);
  return { ...def, label: grown.label ?? def.label, inputs: side('inputs'), outputs: side('outputs') };
}

/** A derived exec pin belongs at the top, above the fixed data ports too. */
function execFirst(ports: PortDef[]): PortDef[] {
  return [...ports.filter((p) => p.type === 'exec'), ...ports.filter((p) => p.type !== 'exec')];
}

/**
 * Why this call cannot do anything, or null if it can. A call is the one node that depends on a
 * *different* graph, so it is the one node that can look perfectly healthy and still be dead.
 */
export function callProblem(node: GraphNode, lookup: GraphLookup, ownerId = ''): string | null {
  if (node.type !== RUN_BEHAVIOR) return null;
  const id = textOf(node.params[BEHAVIOR_PARAM] ?? '');
  if (!id) return 'No behavior picked';
  if (id === ownerId) return 'A behavior cannot run itself';
  const program = lookup.behavior(id);
  if (!program) return 'That behavior is gone';
  if (!terminalNode(program.graph, BEHAVIOR_START)) return 'No start node – does nothing';
  return null;
}

/**
 * Everything that changes how a node looks, as one string. Views and the inspector rebuild when it
 * changes – a port list that is derived rather than fixed has no other way of being noticed.
 */
export function portSignature(node: GraphNode, graph: Graph, lookup: GraphLookup, ownerId = ''): string {
  const def = resolveDef(node, graph, lookup);
  if (!def) return 'missing';
  const list = (ports: PortDef[]) => ports.map((p) => `${p.key}:${p.type}`).join(',');
  return `${node.type}|${def.label}|${list(def.inputs)}|${list(def.outputs)}|${
    callProblem(node, lookup, ownerId) ?? ''
  }`;
}