import { useRef, useState, type PointerEvent as ReactPointerEvent } from 'react';

import type { SheetWidget, SystemDefinition, WidgetType } from '../shared/types.ts';
import { WidgetPreview } from './WidgetPreview.tsx';

const PALETTE: Array<{ type: WidgetType; label: string; defaultBind?: string; w: number; h: number }> = [
  { type: 'section', label: 'Section', w: 220, h: 40 },
  { type: 'number', label: 'Number', defaultBind: 'attr.str', w: 110, h: 72 },
  { type: 'modBadge', label: 'Mod badge', defaultBind: 'derived.strMod', w: 110, h: 72 },
  { type: 'dots', label: 'Dots', defaultBind: 'attr.str', w: 160, h: 72 },
  { type: 'track', label: 'Track / HP', defaultBind: 'resource.hp', w: 220, h: 80 },
  { type: 'skillList', label: 'Skill list', w: 280, h: 240 },
  { type: 'notes', label: 'Notes', defaultBind: 'meta.notes', w: 280, h: 140 },
  { type: 'locationBar', label: 'Armor zones', w: 360, h: 90 },
  { type: 'text', label: 'Text', defaultBind: 'meta.title', w: 200, h: 60 },
];

type Props = {
  system: SystemDefinition;
  onChange: (next: SystemDefinition) => void;
  locale: 'ru' | 'en';
};

function snap(n: number, grid = 8): number {
  return Math.round(n / grid) * grid;
}

export function DesignerWorkspace({ system, onChange, locale }: Props) {
  const [selectedId, setSelectedId] = useState<string | null>(null);
  const [pageIndex, setPageIndex] = useState(0);
  const dragRef = useRef<{
    id: string;
    mode: 'move' | 'resize';
    startX: number;
    startY: number;
    orig: { x: number; y: number; w: number; h: number };
  } | null>(null);

  const page = system.sheetLayout.pages[pageIndex] ?? system.sheetLayout.pages[0];
  const selected = page?.widgets.find((w) => w.id === selectedId) ?? null;

  function updateWidgets(mutator: (widgets: SheetWidget[]) => SheetWidget[]) {
    if (!page) return;
    const pages = system.sheetLayout.pages.map((p, i) =>
      i === pageIndex ? { ...p, widgets: mutator(p.widgets) } : p,
    );
    onChange({ ...system, sheetLayout: { ...system.sheetLayout, pages } });
  }

  function addWidget(item: (typeof PALETTE)[number]) {
    if (!page) return;
    const id = `w_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 6)}`;
    const widget: SheetWidget = {
      id,
      type: item.type,
      bind: item.defaultBind,
      frame: {
        x: snap(24 + (page.widgets.length % 5) * 16),
        y: snap(24 + (page.widgets.length % 7) * 16),
        w: item.w,
        h: item.h,
      },
      props: {
        label: item.label,
        title: item.label,
        max: item.type === 'dots' ? 5 : 20,
      },
    };
    updateWidgets((ws) => [...ws, widget]);
    setSelectedId(id);
  }

  function onPointerDownWidget(e: ReactPointerEvent, id: string, mode: 'move' | 'resize') {
    e.stopPropagation();
    e.preventDefault();
    const w = page?.widgets.find((x) => x.id === id);
    if (!w) return;
    setSelectedId(id);
    dragRef.current = {
      id,
      mode,
      startX: e.clientX,
      startY: e.clientY,
      orig: { ...w.frame },
    };
    (e.target as HTMLElement).setPointerCapture?.(e.pointerId);
  }

  function onPointerMove(e: ReactPointerEvent) {
    const d = dragRef.current;
    if (!d) return;
    const dx = e.clientX - d.startX;
    const dy = e.clientY - d.startY;
    updateWidgets((ws) =>
      ws.map((w) => {
        if (w.id !== d.id) return w;
        if (d.mode === 'move') {
          return {
            ...w,
            frame: {
              ...w.frame,
              x: snap(Math.max(0, d.orig.x + dx)),
              y: snap(Math.max(0, d.orig.y + dy)),
            },
          };
        }
        return {
          ...w,
          frame: {
            ...w.frame,
            w: snap(Math.max(48, d.orig.w + dx)),
            h: snap(Math.max(36, d.orig.h + dy)),
          },
        };
      }),
    );
  }

  function onPointerUp() {
    dragRef.current = null;
  }

  function patchSelected(patch: Partial<SheetWidget> & { props?: Record<string, unknown> }) {
    if (!selected) return;
    updateWidgets((ws) =>
      ws.map((w) =>
        w.id === selected.id
          ? {
              ...w,
              ...patch,
              props: { ...w.props, ...patch.props },
            }
          : w,
      ),
    );
  }

  function removeSelected() {
    if (!selected) return;
    updateWidgets((ws) => ws.filter((w) => w.id !== selected.id));
    setSelectedId(null);
  }

  function addBrick(kind: 'attributes' | 'skills' | 'resources' | 'derived') {
    const key = `new_${Date.now().toString(36).slice(-4)}`;
    const bricks = { ...system.bricks };
    if (kind === 'attributes') {
      bricks.attributes = [
        ...(bricks.attributes ?? []),
        { key, label: key.toUpperCase(), scale: 'numeric', min: 1, max: 20, default: 10 },
      ];
    } else if (kind === 'skills') {
      bricks.skills = [
        ...(bricks.skills ?? []),
        { key, label: key, scale: 'numeric', default: 0 },
      ];
    } else if (kind === 'resources') {
      bricks.resources = [
        ...(bricks.resources ?? []),
        { key, label: key, min: 0, default: 0, track: true },
      ];
    } else {
      bricks.derived = [
        ...(bricks.derived ?? []),
        {
          key,
          label: key,
          formula: 'floor((attr.str - 10) / 2)',
          dependsOn: ['attr.str'],
        },
      ];
    }
    onChange({ ...system, bricks });
  }

  function removeBrick(kind: 'attributes' | 'skills' | 'resources' | 'derived', key: string) {
    const bricks = { ...system.bricks };
    if (kind === 'attributes') bricks.attributes = (bricks.attributes ?? []).filter((a) => a.key !== key);
    if (kind === 'skills') bricks.skills = (bricks.skills ?? []).filter((a) => a.key !== key);
    if (kind === 'resources') bricks.resources = (bricks.resources ?? []).filter((a) => a.key !== key);
    if (kind === 'derived') bricks.derived = (bricks.derived ?? []).filter((a) => a.key !== key);
    onChange({ ...system, bricks });
  }

  const bindOptions: string[] = [];
  for (const a of system.bricks.attributes ?? []) bindOptions.push(`attr.${a.key}`);
  for (const s of system.bricks.skills ?? []) bindOptions.push(`skill.${s.key}`);
  for (const r of system.bricks.resources ?? []) bindOptions.push(`resource.${r.key}`);
  for (const d of system.bricks.derived ?? []) bindOptions.push(`derived.${d.key}`);
  bindOptions.push('meta.notes', 'meta.title');

  return (
    <div className="designerGrid" data-testid="designer-workspace">
      <div className="panel designerSide">
        <div className="sideTitle">{locale === 'ru' ? 'Палитра' : 'Palette'}</div>
        <div className="palette">
          {PALETTE.map((item) => (
            <button
              key={item.type + item.label}
              type="button"
              className="paletteItem"
              data-testid={`palette-${item.type}`}
              onClick={() => addWidget(item)}
            >
              {item.label}
            </button>
          ))}
        </div>

        <div className="sideTitle">{locale === 'ru' ? 'Кирпичики' : 'Bricks'}</div>
        <div className="row wrap">
          <button type="button" onClick={() => addBrick('attributes')}>+ Attr</button>
          <button type="button" onClick={() => addBrick('skills')}>+ Skill</button>
          <button type="button" onClick={() => addBrick('resources')}>+ Resource</button>
          <button type="button" onClick={() => addBrick('derived')}>+ Derived</button>
        </div>
        <div className="brickList">
          {(system.bricks.attributes ?? []).map((a) => (
            <div key={a.key} className="brickRow">
              <code>attr.{a.key}</code>
              <button type="button" onClick={() => removeBrick('attributes', a.key)}>×</button>
            </div>
          ))}
          {(system.bricks.skills ?? []).map((a) => (
            <div key={a.key} className="brickRow">
              <code>skill.{a.key}</code>
              <button type="button" onClick={() => removeBrick('skills', a.key)}>×</button>
            </div>
          ))}
          {(system.bricks.resources ?? []).map((a) => (
            <div key={a.key} className="brickRow">
              <code>resource.{a.key}</code>
              <button type="button" onClick={() => removeBrick('resources', a.key)}>×</button>
            </div>
          ))}
          {(system.bricks.derived ?? []).map((a) => (
            <div key={a.key} className="brickRow">
              <code>derived.{a.key}</code>
              <button type="button" onClick={() => removeBrick('derived', a.key)}>×</button>
            </div>
          ))}
        </div>
      </div>

      <div
        className="designerCanvasHost"
        onPointerMove={onPointerMove}
        onPointerUp={onPointerUp}
        onClick={() => setSelectedId(null)}
      >
        <div className="row" style={{ marginBottom: 8 }}>
          {system.sheetLayout.pages.map((p, i) => (
            <button
              key={p.id}
              type="button"
              className={i === pageIndex ? 'primary' : ''}
              onClick={(e) => {
                e.stopPropagation();
                setPageIndex(i);
              }}
            >
              {p.label}
            </button>
          ))}
          <button
            type="button"
            onClick={(e) => {
              e.stopPropagation();
              const id = `page_${Date.now().toString(36)}`;
              onChange({
                ...system,
                sheetLayout: {
                  ...system.sheetLayout,
                  pages: [
                    ...system.sheetLayout.pages,
                    { id, label: `Page ${system.sheetLayout.pages.length + 1}`, widgets: [] },
                  ],
                },
              });
              setPageIndex(system.sheetLayout.pages.length);
            }}
          >
            + Page
          </button>
        </div>

        <div className="sheetCanvas designMode" data-testid="sheet-canvas">
          {(page?.widgets ?? []).map((w) => (
            <div
              key={w.id}
              className={`widget${selectedId === w.id ? ' selected' : ''}`}
              data-testid={`widget-${w.id}`}
              style={{ left: w.frame.x, top: w.frame.y, width: w.frame.w, height: w.frame.h }}
              onClick={(e) => {
                e.stopPropagation();
                setSelectedId(w.id);
              }}
              onPointerDown={(e) => onPointerDownWidget(e, w.id, 'move')}
            >
              <div className="widgetChrome">{w.type}{w.bind ? ` · ${w.bind}` : ''}</div>
              <div className="widgetBody">
                <WidgetPreview widget={w} system={system} />
              </div>
              <div
                className="resizeHandle"
                onPointerDown={(e) => onPointerDownWidget(e, w.id, 'resize')}
              />
            </div>
          ))}
        </div>
      </div>

      <div className="panel designerSide">
        <div className="sideTitle">{locale === 'ru' ? 'Свойства' : 'Properties'}</div>
        {!selected ? (
          <div className="muted">{locale === 'ru' ? 'Выберите виджет' : 'Select a widget'}</div>
        ) : (
          <div className="propsForm">
            <label>
              Type
              <input value={selected.type} disabled />
            </label>
            <label>
              Bind
              <select
                data-testid="widget-bind"
                value={selected.bind ?? ''}
                onChange={(e) => patchSelected({ bind: e.target.value || undefined })}
              >
                <option value="">—</option>
                {bindOptions.map((b) => (
                  <option key={b} value={b}>
                    {b}
                  </option>
                ))}
              </select>
            </label>
            <label>
              Label
              <input
                value={String(selected.props?.label ?? selected.props?.title ?? '')}
                onChange={(e) => patchSelected({ props: { label: e.target.value, title: e.target.value } })}
              />
            </label>
            <label>
              Max
              <input
                type="number"
                value={Number(selected.props?.max ?? 0)}
                onChange={(e) => patchSelected({ props: { max: Number(e.target.value) } })}
              />
            </label>
            <button type="button" data-testid="remove-widget" onClick={removeSelected}>
              {locale === 'ru' ? 'Удалить виджет' : 'Remove widget'}
            </button>
          </div>
        )}

        <div className="sideTitle" style={{ marginTop: 16 }}>
          System
        </div>
        <label className="propsForm">
          ID
          <input
            data-testid="system-id"
            value={system.id}
            onChange={(e) => onChange({ ...system, id: e.target.value.trim() || system.id })}
          />
        </label>
        <label className="propsForm">
          Edition
          <input
            value={system.edition ?? ''}
            onChange={(e) => onChange({ ...system, edition: e.target.value })}
          />
        </label>
        <label className="propsForm">
          Description
          <textarea
            rows={4}
            value={system.description ?? ''}
            onChange={(e) => onChange({ ...system, description: e.target.value })}
          />
        </label>
      </div>
    </div>
  );
}