import {
  ApplyOverrideToAssetCommand,
  ApplyOverrideToContainerCommand,
  ApplyPositionToContainerCommand,
  RevertOverrideToTemplateCommand,
  RevertPositionToTemplateCommand,
} from '../../core/commands/applyCommands';
import type { Command } from '../../core/commands/Command';
import { UnpackContainerCommand } from '../../core/commands/containerCommands';
import {
  ClearOverrideCommand,
  MoveSceneObjectCommand,
  RenameSceneObjectCommand,
  SetEditorOffsetCommand,
  SetOverrideCommand,
  SetParentCommand,
} from '../../core/commands/sceneObjectCommands';
import type { Asset } from '../../core/model/Asset';
import { findObject, isSelfOrAncestor, treeOrder } from '../../core/model/hierarchy';
import {
  type InstanceTarget,
  instanceTargetOf,
  isLiveInstance,
  isTemplateContent,
  objectRef,
  type ObjectRef,
  resolvedHolder,
} from '../../core/model/instance';
import type { Axis, PropertyBag, PropertyValue } from '../../core/model/Properties';
import { findAsset, findObjectHolder, type ObjectHolder, type Project } from '../../core/model/Project';
import type { SceneObject } from '../../core/model/SceneObject';
import {
  COMMON_PROPS,
  isCommonProp,
  type PropertyDef,
  schemaForAsset,
} from '../../core/properties/PropertySchema';
import {
  deviatesFromAsset,
  deviatesFromTemplate,
  resolveSceneObjectProps,
} from '../../core/properties/resolve';
import { Button, Dropdown, Label, Menu, type MenuItem, TextField } from '../../ui';
import { addCollider, createContainer, removeObjects } from '../actions';
import { aspectActions } from './aspectAction';
import { createFieldRow, type FieldActions, type FieldRow, labelledRow } from './fieldFactory';
import { addGap, addNote, addTitle, type InspectorHost } from './host';
import { previewingHandlers } from './previewHandlers';

const POSITION_AXES: readonly Axis[] = ['x', 'y', 'z'];
const OFFSET_AXES = ['x', 'y'] as const;

const offsetKey = (axis: 'x' | 'y') => `editorOffset${axis.toUpperCase()}`;

/** The holder with the content of placed containers resolved in – what the inspector addresses. */
function viewOf(project: Project, holderId: string): ObjectHolder | undefined {
  const holder = findObjectHolder(project, holderId);
  return holder && resolvedHolder(project, holder);
}

function targetOf(project: Project, holderId: string, objectId: string): InstanceTarget | undefined {
  const holder = findObjectHolder(project, holderId);
  return holder && instanceTargetOf(project, holder, objectId);
}

/** Structure-defining facts of an object selection: parent, template link and schema. */
export function objectSignature(
  project: Project,
  holderId: string,
  objectIds: readonly string[],
  objectId: string,
): string {
  if (objectIds.length > 1) return `multi|${objectIds.join(',')}`;
  const holder = findObjectHolder(project, holderId);
  const view = holder && resolvedHolder(project, holder);
  const object = view && findObject(view, objectId);
  const asset = object && findAsset(project, object.assetId);
  if (!holder || !object || !asset) return 'missing';
  const kind = isTemplateContent(holder, objectId)
    ? 'template'
    : isLiveInstance(project, holder, object)
      ? 'instance'
      : '';
  return (
    `${object.parentId}|${kind}|` +
    schemaForAsset(asset)
      .map((d) => `${d.key}:${d.kind}`)
      .join(',')
  );
}

/** Several objects: what they are, and the actions that apply to all of them at once. */
export function buildObjectsSection(host: InspectorHost, holderId: string, objectIds: string[]): void {
  const view = viewOf(host.state.project, holderId);
  if (!view) return;
  addTitle(host, `${objectIds.length} OBJECTS SELECTED`);
  for (const id of objectIds) {
    const object = findObject(view, id);
    const asset = object && findAsset(host.state.project, object.assetId);
    if (object && asset) addNote(host, `${object.name || asset.name}  ·  ${asset.type}`);
  }
  addGap(host);
  addNote(host, 'Ctrl-click adds or removes objects.', 'small');
  addNote(host, 'Dragging one in the viewport moves all of them.', 'small');
  addGap(host);
  const holder = findObjectHolder(host.state.project, holderId)!;
  if (objectIds.some((id) => isTemplateContent(holder, id))) {
    addNote(host, 'Part of the selection comes from a container', 'small');
    addNote(host, 'template, so grouping and removing are off.', 'small');
    return;
  }
  host.body.add(
    new Button('Create container', { onClick: () => createContainer(host.state, holderId, objectIds) }),
  );
  addNote(host, 'Groups the selection into a reusable container', 'small');
  addNote(host, 'asset placed at its centre (Ctrl+G).', 'small');
  addGap(host);
  host.body.add(
    new Button('Remove', {
      variant: 'danger',
      onClick: () => removeObjects(host.state, holderId, objectIds),
    }),
  );
}

/** One object: name, asset, parent, container link, the switch, position, editor offset, properties, collider button. */
export function buildObjectSection(host: InspectorHost, holderId: string, objectId: string): void {
  const { project } = host.state;
  const view = viewOf(project, holderId);
  const object = view && findObject(view, objectId);
  const asset = object && findAsset(project, object.assetId);
  if (!view || !object || !asset) return;
  const target = targetOf(project, holderId, objectId);

  addTitle(host, `${asset.type.toUpperCase()} OBJECT`);
  host.nameField = new TextField(object.name, {
    placeholder: asset.name,
    onChange: (name) => host.state.execute(new RenameSceneObjectCommand(holderId, objectId, name.trim())),
  });
  const nameRow = labelledRow('Name');
  nameRow.row.add(host.nameField, 1);
  host.body.add(nameRow.row);

  const assetRow = labelledRow('Asset');
  assetRow.row.add(
    new Button(asset.name, {
      variant: 'ghost',
      onClick: () => host.state.select({ kind: 'asset', assetId: asset.id }),
    }),
    1,
  );
  host.body.add(assetRow.row);

  host.body.add(parentRow(host, view, object, target !== undefined));

  // Content of a placed container: values compare against the template, not just the asset.
  if (target) {
    const linkRow = labelledRow('Part of');
    linkRow.row.add(
      new Button(target.asset.name, {
        variant: 'ghost',
        onClick: () => host.state.select({ kind: 'asset', assetId: target.asset.id }),
      }),
      1,
    );
    host.body.add(linkRow.row);
  }

  // The master switch, right where it is looked for: above everything type-specific.
  for (const def of COMMON_PROPS)
    propertyRow(host, holderId, objectId, asset, def, resolveSceneObjectProps(asset, object));

  addTitle(host, object.parentId ? 'POSITION (LOCAL TO PARENT)' : 'POSITION');
  for (const axis of POSITION_AXES) {
    const moved = () => positionMoved(host.state, holderId, objectId, axis);
    componentRow(host, holderId, objectId, object.position[axis], {
      key: axis,
      label: axis.toUpperCase(),
      axis,
      read: (ref) => ref.object.position,
      write: (ref, value) => ref.setPosition(value),
      command: (v) => new MoveSceneObjectCommand(holderId, objectId, v),
      reset: () =>
        moved()
          ? [
              {
                label: 'Reset to container',
                onSelect: () =>
                  host.state.execute(new RevertPositionToTemplateCommand(holderId, objectId, axis)),
              },
            ]
          : [],
      apply: () =>
        moved()
          ? [
              {
                label: 'Apply to container',
                onSelect: () =>
                  host.state.execute(new ApplyPositionToContainerCommand(holderId, objectId, axis)),
              },
            ]
          : [],
    });
  }

  // Where the object is *drawn* in the viewport, nothing else – for pulling stacked objects apart.
  addTitle(host, 'EDITOR OFFSET (SCENE VIEW ONLY)');
  for (const axis of OFFSET_AXES) {
    componentRow(host, holderId, objectId, object.editorOffset[axis], {
      key: offsetKey(axis),
      label: `Offset ${axis.toUpperCase()}`,
      axis,
      read: (ref) => ref.object.editorOffset,
      write: (ref, value) => ref.setEditorOffset(value),
      command: (v) => new SetEditorOffsetCommand(holderId, objectId, v),
      // No apply: the offset never leaves the placed object.
      reset: () => {
        const current = currentRef(host.state, holderId, objectId)?.object;
        if (!current || current.editorOffset[axis] === 0) return [];
        return [
          {
            label: 'Reset to 0',
            onSelect: () =>
              host.state.execute(
                new SetEditorOffsetCommand(holderId, objectId, { ...current.editorOffset, [axis]: 0 }),
              ),
          },
        ];
      },
    });
  }

  // Asset properties (or behavior variables) with overrides; the common switch is shown above.
  const schema = schemaForAsset(asset);
  const values = resolveSceneObjectProps(asset, object);
  const own = schema.filter((def) => !isCommonProp(def.key));
  if (own.length > 0 || asset.type === 'behavior')
    addTitle(host, asset.type === 'behavior' ? 'VARIABLES' : 'PROPERTIES');
  if (own.length === 0 && asset.type === 'behavior') addNote(host, 'The behavior declares no variables.');
  for (const def of own) propertyRow(host, holderId, objectId, asset, def, values);
  markObjectRows(host, object, asset, target);

  if (asset.type === 'container') contentSection(host, holderId, object, asset.objects.length);

  if (asset.type !== 'collider' && !target) {
    addGap(host);
    host.body.add(
      new Button('+ Add collider', {
        variant: 'ghost',
        onClick: () => addCollider(host.state, holderId, objectId),
      }),
    );
  }
}

/**
 * What a placed container holds. While it follows its template the content cannot be changed here –
 * unpacking writes it into the scene as ordinary objects, which cuts the link for good.
 */
function contentSection(
  host: InspectorHost,
  holderId: string,
  object: SceneObject,
  templateCount: number,
): void {
  const holder = findObjectHolder(host.state.project, holderId);
  const live = Boolean(holder && isLiveInstance(host.state.project, holder, object));
  addTitle(host, 'CONTENT');
  if (!live) {
    addNote(host, 'Unpacked: its content is stored in the scene.');
    return;
  }
  addNote(
    host,
    templateCount === 0 ? 'The container is empty.' : `Follows a template of ${templateCount} object(s).`,
  );
  if (templateCount === 0) return;
  addNote(host, 'Its content is listed below it in the hierarchy.', 'small');
  addGap(host);
  host.body.add(
    new Button('Unpack', {
      variant: 'ghost',
      onClick: () => host.state.execute(new UnpackContainerCommand(holderId, object.id)),
    }),
  );
  addNote(host, 'Copies the content into the scene and stops', 'small');
  addNote(host, 'following the template.', 'small');
}

/** Pushes the current model values into the rows. False when the object is gone (rebuild). */
export function refreshObjectSection(host: InspectorHost, holderId: string, objectId: string): boolean {
  const { project } = host.state;
  const view = viewOf(project, holderId);
  const object = view && findObject(view, objectId);
  const asset = object && findAsset(project, object.assetId);
  if (!view || !object || !asset) return false;
  host.nameField?.setValue(object.name);
  for (const axis of POSITION_AXES) host.fields.get(axis)?.setValue(object.position[axis]);
  for (const axis of OFFSET_AXES) host.fields.get(offsetKey(axis))?.setValue(object.editorOffset[axis]);
  const values = resolveSceneObjectProps(asset, object);
  for (const def of schemaForAsset(asset)) host.fields.get(def.key)?.setValue(values[def.key] ?? def.default);
  markObjectRows(host, object, asset, targetOf(project, holderId, objectId));
  return true;
}

interface ComponentSpec<V extends object> {
  key: string;
  label: string;
  axis: keyof V & string;
  read: (ref: ObjectRef) => V;
  write: (ref: ObjectRef, value: V) => void;
  command: (value: V) => Command;
  reset?: FieldActions;
  apply?: FieldActions;
}

/**
 * A number row editing one component of a vector on the object (position, editor offset).
 * The row edits one axis, the command carries the whole vector: the other components come
 * from the target after the preview was taken back, so they are the pre-preview ones.
 */
function componentRow<V extends object>(
  host: InspectorHost,
  holderId: string,
  objectId: string,
  value: number,
  spec: ComponentSpec<V>,
): void {
  const withAxis = (vector: V, next: PropertyValue): V => ({ ...vector, [spec.axis]: Number(next) });
  const row = createFieldRow(
    host,
    { key: spec.key, label: spec.label, kind: 'number', default: 0, step: 1 },
    value,
    previewingHandlers<ObjectRef, V>(host, {
      target: () => currentRef(host.state, holderId, objectId),
      // Copied: the snapshot outlives the scrub, the vector in the model does not.
      read: (ref) => ({ ...spec.read(ref) }),
      write: spec.write,
      toModel: (next, ref) => withAxis(spec.read(ref), next),
      commit: spec.command,
    }),
    { reset: spec.reset, apply: spec.apply },
  );
  host.fields.set(spec.key, row);
  host.body.add(row.row);
}

/**
 * One editable property of a placed object: writes an override, offers ↺ (back to the asset
 * or, inside a container, to the template) and ↑ (apply upwards).
 *
 * Inside a container a value has two bases – the template it follows and, one step further up,
 * the asset. Reset always goes to the nearest one, so content of a placed container offers only
 * "Reset to container"; "Apply to asset" still reaches past it, dropping the template's override.
 */
function propertyRow(
  host: InspectorHost,
  holderId: string,
  objectId: string,
  owner: Asset,
  def: PropertyDef,
  values: Record<string, PropertyValue>,
): FieldRow {
  const bases = () => deviations(host.state, holderId, objectId, def.key);
  const row = createFieldRow(
    host,
    def,
    values[def.key] ?? def.default,
    previewingHandlers<ObjectRef>(host, {
      target: () => currentRef(host.state, holderId, objectId),
      read: (ref) => ref.object.overrides[def.key],
      write: (ref, value) => ref.setOverride(def.key, value),
      remove: (ref) => ref.setOverride(def.key, undefined),
      commit: (value) => new SetOverrideCommand(holderId, objectId, def.key, value),
    }),
    {
      extra: aspectActions(
        host,
        owner,
        def,
        () => currentProps(host.state, holderId, objectId),
        (value) => host.state.execute(new SetOverrideCommand(holderId, objectId, def.key, value)),
      ),
      reset: () => {
        const { template, asset } = bases();
        return [
          ...(template
            ? [
                {
                  label: 'Reset to container',
                  onSelect: () =>
                    host.state.execute(new RevertOverrideToTemplateCommand(holderId, objectId, def.key)),
                },
              ]
            : []),
          ...(asset
            ? [
                {
                  label: 'Reset to asset',
                  onSelect: () => host.state.execute(new ClearOverrideCommand(holderId, objectId, def.key)),
                },
              ]
            : []),
        ];
      },
      apply: () => {
        const { template, applyToAsset } = bases();
        return [
          ...(template
            ? [
                {
                  label: 'Apply to container',
                  onSelect: () =>
                    host.state.execute(new ApplyOverrideToContainerCommand(holderId, objectId, def.key)),
                },
              ]
            : []),
          ...(applyToAsset
            ? [
                {
                  label: 'Apply to asset',
                  onSelect: () =>
                    host.state.execute(new ApplyOverrideToAssetCommand(holderId, objectId, def.key)),
                },
              ]
            : []),
        ];
      },
    },
  );
  host.fields.set(def.key, row);
  host.body.add(row.row);
  return row;
}

/**
 * "Parent: <name> ▾" – picks another object of the same scene or container, or none. The object's own
 * subtree is excluded (that would be a cycle). For behaviors the parent is the owner. Content of a
 * placed container only shows its parent: where it hangs is the template's business.
 */
function parentRow(host: InspectorHost, holder: ObjectHolder, object: SceneObject, fixed: boolean) {
  const { row } = labelledRow('Parent');
  const nameOf = (o: SceneObject) => o.name || findAsset(host.state.project, o.assetId)?.name || '?';
  const parent = findObject(holder, object.parentId);
  const name = parent ? nameOf(parent) : 'None';
  if (fixed) {
    row.add(new Label(name, { style: 'muted' }), 1);
    return row;
  }
  const button = new Dropdown(name);
  button.onClick = () => {
    // Resolved anew on every open: `holder` is a derived copy of the scene, so one captured when
    // the row was built lists the objects of that moment, not the ones there now.
    const current = viewOf(host.state.project, holder.id) ?? holder;
    const items: MenuItem[] = [
      { label: 'None', onSelect: () => host.state.execute(new SetParentCommand(holder.id, object.id, '')) },
    ];
    for (const { object: candidate, depth } of treeOrder(current)) {
      if (isSelfOrAncestor(current, object.id, candidate.id)) continue;
      const label = `${'   '.repeat(depth)}${nameOf(candidate)}`;
      items.push({
        label: candidate.id === object.parentId ? `● ${label}` : label,
        onSelect: () => host.state.execute(new SetParentCommand(holder.id, object.id, candidate.id)),
      });
    }
    // Searchable: this lists every object of the scene or container, which grows with the project.
    new Menu(items, { searchable: true }).openBelow(button);
  };
  row.add(button, 1);
  return row;
}

/**
 * Bold marks exactly what the ↺/↑ buttons offer: for content of a placed container a deviation
 * from the template (position per axis, overrides), for any other object one from the asset. The
 * editor offset has one base only – no offset at all.
 */
function markObjectRows(
  host: InspectorHost,
  object: SceneObject,
  asset: Asset,
  target: InstanceTarget | undefined,
): void {
  for (const axis of POSITION_AXES)
    host.fields
      .get(axis)
      ?.setModified(Boolean(target) && object.position[axis] !== target!.template.position[axis]);
  for (const axis of OFFSET_AXES)
    host.fields.get(offsetKey(axis))?.setModified(object.editorOffset[axis] !== 0);
  for (const def of schemaForAsset(asset)) {
    const deviates = target
      ? deviatesFromTemplate(object, target.template, def.key)
      : deviatesFromAsset(object, asset, def.key);
    host.fields.get(def.key)?.setModified(deviates);
  }
}

/**
 * What the ↺/↑ menus may offer, each only when it actually differs. Reset goes to the nearest base
 * only: dropping a deviation inside a container lands on the template, never past it. Evaluated on
 * demand so a menu never acts on a stale snapshot.
 */
function deviations(
  state: InspectorHost['state'],
  holderId: string,
  objectId: string,
  key: string,
): { template: boolean; asset: boolean; applyToAsset: boolean } {
  const view = viewOf(state.project, holderId);
  const object = view && findObject(view, objectId);
  const asset = object && findAsset(state.project, object.assetId);
  if (!view || !object || !asset) return { template: false, asset: false, applyToAsset: false };
  const target = targetOf(state.project, holderId, objectId);
  const fromAsset = deviatesFromAsset(object, asset, key);
  return {
    template: Boolean(target) && deviatesFromTemplate(object, target!.template, key),
    asset: !target && fromAsset,
    applyToAsset: fromAsset,
  };
}

/** Whether the object sits somewhere else on `axis` than its container template says. */
function positionMoved(
  state: InspectorHost['state'],
  holderId: string,
  objectId: string,
  axis: Axis,
): boolean {
  const target = targetOf(state.project, holderId, objectId);
  const object = currentRef(state, holderId, objectId)?.object;
  return Boolean(target && object) && object!.position[axis] !== target!.template.position[axis];
}

function currentRef(
  state: InspectorHost['state'],
  holderId: string,
  objectId: string,
): ObjectRef | undefined {
  const holder = findObjectHolder(state.project, holderId);
  return holder && objectRef(state.project, holder, objectId);
}

/** The values the object shows right now, asset defaults and overrides merged. */
function currentProps(state: InspectorHost['state'], holderId: string, objectId: string): PropertyBag | null {
  const object = currentRef(state, holderId, objectId)?.object;
  const asset = object && findAsset(state.project, object.assetId);
  return object && asset ? resolveSceneObjectProps(asset, object) : null;
}