import { computed, type Ref } from "vue";
import type { ProjectFile } from "../../domain/project";
import type { Node, VariantGroupNode } from "../../domain/phy";
import {
  apply,
  compose,
  flattenKeys,
  inverse,
  matrix,
  worldTransform,
  type Affine,
} from "../../domain/geometry";
import { removeFocusedSubtree, structuralNodes } from "./logic";

type Options = {
  project: () => ProjectFile;
  size: Ref<{ w: number; h: number }>;
  pan: Ref<{ x: number; y: number }>;
  zoom: Ref<number>;
  focus: Ref<string | null>;
  variants: Ref<Record<string, string>>;
  grid: Ref<number>;
  selected: Ref<string[]>;
  node: (id: string) => Node | undefined;
  parentId: (id: string) => string | null;
  parentLabel: (id: string | null) => string;
  selectedContainer: (id: string) => string | null;
};

export function usePhyCanvasView(options: Options) {
  const keys = computed(() => flattenKeys(options.project().phy, options.variants.value));
  const groupsAll = computed(() => structuralNodes(options.project().phy.root));
  const outsideNodes = computed(() =>
    options.focus.value ? removeFocusedSubtree(options.project().phy.root, options.focus.value) : [],
  );
  const gridLines = computed(() => {
    const step = options.grid.value;
    const xMin = Math.floor(-options.pan.value.x / options.zoom.value / step);
    const xMax = Math.ceil((options.size.value.w - options.pan.value.x) / options.zoom.value / step);
    const yMin = Math.floor(-options.pan.value.y / options.zoom.value / step);
    const yMax = Math.ceil((options.size.value.h - options.pan.value.y) / options.zoom.value / step);
    const lines: { d: string; major: boolean }[] = [];
    for (let index = xMin; index <= xMax; index++) {
      lines.push({ d: `M ${index * step} -100 V 100`, major: Math.abs((index * step) % 1) < 1e-8 });
    }
    for (let index = yMin; index <= yMax; index++) {
      lines.push({ d: `M -100 ${index * step} H 100`, major: Math.abs((index * step) % 1) < 1e-8 });
    }
    return lines;
  });
  const variantGroups = computed(() =>
    groupsAll.value.filter((node): node is VariantGroupNode => node.type === "variantGroup"),
  );
  const focusGridLines = computed(() => {
    const focusId = options.focus.value;
    if (!focusId || !options.node(focusId)) return [];
    const screen = compose(
      {
        a: options.zoom.value,
        b: 0,
        c: 0,
        d: options.zoom.value,
        e: options.pan.value.x,
        f: options.pan.value.y,
      },
      worldTransform(options.project().phy, focusId),
    );
    const toLocal = inverse(screen);
    const corners = [
      { x: 0, y: 0 },
      { x: options.size.value.w, y: 0 },
      { x: options.size.value.w, y: options.size.value.h },
      { x: 0, y: options.size.value.h },
    ].map((point) => apply(toLocal, point));
    const xs = corners.map((point) => point.x);
    const ys = corners.map((point) => point.y);
    const step = options.grid.value;
    const lines: { d: string; major: boolean }[] = [];
    for (
      let index = Math.floor(Math.min(...xs) / step);
      index <= Math.ceil(Math.max(...xs) / step);
      index++
    ) {
      lines.push({ d: `M ${index * step} -100 V 100`, major: Math.abs((index * step) % 1) < 1e-8 });
    }
    for (
      let index = Math.floor(Math.min(...ys) / step);
      index <= Math.ceil(Math.max(...ys) / step);
      index++
    ) {
      lines.push({ d: `M -100 ${index * step} H 100`, major: Math.abs((index * step) % 1) < 1e-8 });
    }
    return lines;
  });
  const moveTargets = computed(() => {
    const excluded = new Set<string>();
    const add = (node: Node) => {
      excluded.add(node.id);
      if (node.type === "cluster") node.children.forEach(add);
      if (node.type === "variantGroup") {
        node.children.forEach((variant) => {
          excluded.add(variant.id);
          variant.children.forEach(add);
        });
      }
    };
    options.selected.value.forEach((id) => {
      const node = options.node(id);
      if (node) add(node);
    });
    return [
      { id: "__root__", label: "root" },
      ...groupsAll.value
        .filter((node) => node.type === "cluster" && !excluded.has(node.id))
        .map((node) => ({ id: node.id, label: node.name || "クラスター" })),
      ...variantGroups.value.flatMap((group) =>
        group.children
          .filter((variant) => !excluded.has(variant.id))
          .map((variant) => ({ id: variant.id, label: `${group.name} / ${variant.name}` })),
      ),
    ];
  });

  function parentMatrix(id: string): Affine {
    const node = options.node(id);
    return node
      ? compose(worldTransform(options.project().phy, id), inverse(matrix(node.transform)))
      : { a: 1, b: 0, c: 0, d: 1, e: 0, f: 0 };
  }

  function focusAngle(id: string) {
    const transform = parentMatrix(id);
    return (Math.atan2(transform.b, transform.a) * 180) / Math.PI;
  }

  function affineText(transform: Affine) {
    return `matrix(${transform.a} ${transform.b} ${transform.c} ${transform.d} ${transform.e} ${transform.f})`;
  }

  function focusCrumbs(id: string): { id: string | null; label: string }[] {
    const ids = [id];
    let parent = options.parentId(id);
    while (parent) {
      ids.unshift(parent);
      parent = options.parentId(parent);
    }
    return [
      { id: null, label: "root" },
      ...ids.map((item) => ({
        id:
          groupsAll.value.find(
            (node) => node.type === "variantGroup" && node.children.some((variant) => variant.id === item),
          )?.id || item,
        label: options.parentLabel(item),
      })),
    ];
  }

  const propertyNode = computed(() =>
    options.selected.value.length === 1 ? options.node(options.selected.value[0]!) : null,
  );

  return {
    keys,
    groupsAll,
    outsideNodes,
    gridLines,
    variantGroups,
    focusGridLines,
    moveTargets,
    parentMatrix,
    focusAngle,
    affineText,
    focusCrumbs,
    propertyNode,
  };
}