import type { CompositorGraphIR, CompositorLinkIR, CompositorNodeIR, CompositorNodeType, CompositorResourceIR } from "./compositor";

function clone(graph: CompositorGraphIR): CompositorGraphIR {
  return structuredClone(graph);
}

/** Commands and pure graph edits for the Compositor canvas. */
export const compositorCommands = Object.freeze({
  evaluate(graph: CompositorGraphIR): CompositorGraphIR {
    return structuredClone(graph);
  },
  setNodeGraph(sceneId: string, graph: CompositorGraphIR) {
    return { type: "setCompositorNodeGraph", sceneId, graph } as const;
  },
  createGraph(id: string, name: string): CompositorGraphIR {
    const composite: CompositorNodeIR = {
      id: "node-composite", type: "COMPOSITE", name: "Composite",
      properties: {}, location: { x: 620, y: 80 },
    };
    return { schemaVersion: 1, id, name, outputNodeId: composite.id, nodes: [composite], links: [], resources: [] };
  },
  addNode(graph: CompositorGraphIR, type: CompositorNodeType, name: string, location?: { x: number; y: number }): CompositorGraphIR {
    const next = clone(graph);
    let index = 1;
    let id = `node-${type.toLowerCase().replaceAll("_", "-")}-${index}`;
    while (next.nodes.some((node) => node.id === id)) id = `node-${type.toLowerCase().replaceAll("_", "-")}-${++index}`;
    const node: CompositorNodeIR = {
      id, type, name, properties: defaultProperties(type),
      location: location ?? { x: 90 + (next.nodes.length % 4) * 210, y: 60 + Math.floor(next.nodes.length / 4) * 150 },
    };
    next.nodes.push(node);
    return next;
  },
  removeNode(graph: CompositorGraphIR, nodeId: string): CompositorGraphIR {
    const next = clone(graph);
    if (nodeId === next.outputNodeId) return graph;
    next.nodes = next.nodes.filter((node) => node.id !== nodeId);
    next.links = next.links.filter((link) => link.fromNodeId !== nodeId && link.toNodeId !== nodeId);
    return next;
  },
  moveNode(graph: CompositorGraphIR, nodeId: string, location: { x: number; y: number }): CompositorGraphIR {
    const next = clone(graph);
    const node = next.nodes.find((candidate) => candidate.id === nodeId);
    if (node) node.location = { x: location.x, y: location.y };
    return next;
  },
  connect(graph: CompositorGraphIR, link: CompositorLinkIR): CompositorGraphIR {
    const next = clone(graph);
    if (!next.nodes.some((node) => node.id === link.fromNodeId) || !next.nodes.some((node) => node.id === link.toNodeId)) return graph;
    next.links = next.links.filter((candidate) => !(candidate.toNodeId === link.toNodeId && candidate.toSocket === link.toSocket));
    next.links.push({ ...link });
    return next;
  },
  disconnect(graph: CompositorGraphIR, toNodeId: string, toSocket: string): CompositorGraphIR {
    const next = clone(graph);
    next.links = next.links.filter((link) => !(link.toNodeId === toNodeId && link.toSocket === toSocket));
    return next;
  },
  setProperty(graph: CompositorGraphIR, nodeId: string, key: string, value: unknown): CompositorGraphIR {
    const next = clone(graph);
    const node = next.nodes.find((candidate) => candidate.id === nodeId);
    if (node) node.properties = { ...node.properties, [key]: value };
    return next;
  },
  upsertResource(graph: CompositorGraphIR, resource: CompositorResourceIR): CompositorGraphIR {
    const next = clone(graph);
    const index = next.resources.findIndex((candidate) => candidate.id === resource.id);
    if (index >= 0) next.resources[index] = { ...resource };
    else next.resources.push({ ...resource });
    return next;
  },
  removeResource(graph: CompositorGraphIR, resourceId: string): CompositorGraphIR {
    const next = clone(graph);
    next.resources = next.resources.filter((resource) => resource.id !== resourceId);
    return next;
  },
  setOutput(graph: CompositorGraphIR, nodeId: string): CompositorGraphIR {
    const next = clone(graph);
    if (next.nodes.find((node) => node.id === nodeId)?.type !== "COMPOSITE") return graph;
    next.outputNodeId = nodeId;
    return next;
  },
});

export function defaultProperties(type: CompositorNodeType): Record<string, unknown> {
  switch (type) {
    case "CONSTANT_COLOR": return { color: [0.2, 0.45, 0.8, 1] };
    case "EXPOSURE": return { exposure: 0 };
    case "INVERT": return {};
    case "BLUR": return { radius: 4 };
    case "MIX": return { factor: 0.5 };
    case "TRANSFORM": return { translateX: 0, translateY: 0, scaleX: 1, scaleY: 1 };
    case "VIEWER": return {};
    default: return {};
  }
}