Schema Diagram

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f9fafb;
  color: #111;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.demo {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.sd-toolbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 20px;
  background: #fff;
  border-bottom: 1px solid #e5e7eb;
  flex-shrink: 0;
}
.sd-title {
  font-size: 15px;
  font-weight: 800;
}
.sd-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
}
.sd-btn {
  padding: 6px 14px;
  background: #f3f4f6;
  border: none;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  color: #374151;
}
.sd-btn:hover {
  background: #e5e7eb;
}
.sd-hint {
  font-size: 12px;
  color: #9ca3af;
}

.sd-canvas {
  flex: 1;
  position: relative;
  overflow: hidden;
  background: #f9fafb;
  background-image: radial-gradient(circle, #d1d5db 1px, transparent 1px);
  background-size: 24px 24px;
}

.sd-svg {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

/* Table node */
.sd-table {
  position: absolute;
  background: #fff;
  border: 1.5px solid #e5e7eb;
  border-radius: 10px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  min-width: 200px;
  cursor: grab;
  user-select: none;
  transition: box-shadow 0.15s;
}
.sd-table:active {
  cursor: grabbing;
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.15);
}
.sd-table.selected {
  border-color: #6366f1;
  box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

.sd-table-header {
  padding: 10px 14px;
  background: #6366f1;
  border-radius: 8px 8px 0 0;
  display: flex;
  align-items: center;
  gap: 8px;
}
.sd-table-icon {
  font-size: 14px;
}
.sd-table-name {
  font-size: 13px;
  font-weight: 800;
  color: #fff;
}

.sd-col {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-top: 1px solid #f3f4f6;
  font-size: 12px;
}
.sd-col:hover {
  background: #f9fafb;
}

.col-key {
  width: 14px;
  font-size: 11px;
  flex-shrink: 0;
}
.col-pk {
  color: #f59e0b;
}
.col-fk {
  color: #6366f1;
}

.col-name {
  flex: 1;
  font-weight: 600;
  color: #111827;
}
.col-type {
  font-size: 11px;
  color: #9ca3af;
  font-family: Menlo, monospace;
}
.col-nullable {
  font-size: 10px;
  color: #d1d5db;
  margin-left: auto;
}

/* Relationship line labels */
.rel-label {
  font-size: 10px;
  fill: #6b7280;
}

const SCHEMA = [
  {
    id: "users",
    name: "users",
    icon: "👤",
    x: 40,
    y: 60,
    cols: [
      { name: "id", type: "uuid", key: "pk" },
      { name: "email", type: "varchar(255)" },
      { name: "name", type: "varchar(100)" },
      { name: "created_at", type: "timestamp", nullable: true },
    ],
  },
  {
    id: "orders",
    name: "orders",
    icon: "📦",
    x: 320,
    y: 40,
    cols: [
      { name: "id", type: "uuid", key: "pk" },
      { name: "user_id", type: "uuid", key: "fk" },
      { name: "status", type: "varchar(20)" },
      { name: "total", type: "numeric(10,2)" },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "order_items",
    name: "order_items",
    icon: "🗂",
    x: 580,
    y: 40,
    cols: [
      { name: "id", type: "uuid", key: "pk" },
      { name: "order_id", type: "uuid", key: "fk" },
      { name: "product_id", type: "uuid", key: "fk" },
      { name: "quantity", type: "integer" },
      { name: "unit_price", type: "numeric(10,2)" },
    ],
  },
  {
    id: "products",
    name: "products",
    icon: "🏷",
    x: 580,
    y: 280,
    cols: [
      { name: "id", type: "uuid", key: "pk" },
      { name: "name", type: "varchar(200)" },
      { name: "price", type: "numeric(10,2)" },
      { name: "stock", type: "integer" },
      { name: "category_id", type: "uuid", key: "fk" },
    ],
  },
  {
    id: "categories",
    name: "categories",
    icon: "🗃",
    x: 320,
    y: 280,
    cols: [
      { name: "id", type: "uuid", key: "pk" },
      { name: "name", type: "varchar(100)" },
      { name: "slug", type: "varchar(100)" },
    ],
  },
];

const RELATIONS = [
  { from: "orders", fromCol: "user_id", to: "users", toCol: "id", label: "1:N" },
  { from: "order_items", fromCol: "order_id", to: "orders", toCol: "id", label: "1:N" },
  { from: "order_items", fromCol: "product_id", to: "products", toCol: "id", label: "1:N" },
  { from: "products", fromCol: "category_id", to: "categories", toCol: "id", label: "N:1" },
];

const canvas = document.getElementById("sdCanvas");
const container = document.getElementById("tableContainer");
const svgEl = document.getElementById("sdSvg");
const linesG = document.getElementById("lines");

const tableEls = {};
const positions = {};

function renderTable(t) {
  const el = document.createElement("div");
  el.className = "sd-table";
  el.id = `tbl-${t.id}`;
  el.style.left = t.x + "px";
  el.style.top = t.y + "px";
  positions[t.id] = { x: t.x, y: t.y };

  let html = `<div class="sd-table-header"><span class="sd-table-icon">${t.icon}</span><span class="sd-table-name">${t.name}</span></div>`;
  t.cols.forEach((col) => {
    const keyHtml =
      col.key === "pk"
        ? `<span class="col-key col-pk">🔑</span>`
        : col.key === "fk"
          ? `<span class="col-key col-fk">🔗</span>`
          : `<span class="col-key"></span>`;
    const nullable = col.nullable ? `<span class="col-nullable">?</span>` : "";
    html += `<div class="sd-col">${keyHtml}<span class="col-name">${col.name}</span><span class="col-type">${col.type}</span>${nullable}</div>`;
  });
  el.innerHTML = html;

  // Drag
  let dragging = false,
    ox = 0,
    oy = 0;
  el.addEventListener("mousedown", (e) => {
    dragging = true;
    ox = e.clientX - positions[t.id].x;
    oy = e.clientY - positions[t.id].y;
    el.classList.add("selected");
    e.preventDefault();
  });
  window.addEventListener("mousemove", (e) => {
    if (!dragging) return;
    const x = e.clientX - ox;
    const y = e.clientY - oy;
    positions[t.id] = { x, y };
    el.style.left = x + "px";
    el.style.top = y + "px";
    renderLines();
  });
  window.addEventListener("mouseup", () => {
    if (dragging) {
      dragging = false;
      el.classList.remove("selected");
    }
  });

  container.appendChild(el);
  tableEls[t.id] = el;
}

function getCenter(id) {
  const el = tableEls[id];
  const { x, y } = positions[id];
  return { x: x + el.offsetWidth / 2, y: y + el.offsetHeight / 2 };
}

function renderLines() {
  linesG.innerHTML = "";
  RELATIONS.forEach((rel) => {
    const fc = getCenter(rel.from);
    const tc = getCenter(rel.to);
    const mx = (fc.x + tc.x) / 2;
    const my = (fc.y + tc.y) / 2;
    const path = document.createElementNS("http://www.w3.org/2000/svg", "path");
    const d = `M ${fc.x} ${fc.y} C ${mx} ${fc.y}, ${mx} ${tc.y}, ${tc.x} ${tc.y}`;
    path.setAttribute("d", d);
    path.setAttribute("stroke", "#9ca3af");
    path.setAttribute("stroke-width", "1.5");
    path.setAttribute("fill", "none");
    path.setAttribute("marker-end", "url(#arrow)");
    linesG.appendChild(path);

    const text = document.createElementNS("http://www.w3.org/2000/svg", "text");
    text.setAttribute("x", mx);
    text.setAttribute("y", (fc.y + tc.y) / 2 - 4);
    text.setAttribute("text-anchor", "middle");
    text.className.baseVal = "rel-label";
    text.textContent = rel.label;
    linesG.appendChild(text);
  });
}

SCHEMA.forEach(renderTable);

// Resize observer to re-render lines when tables are sized
const ro = new ResizeObserver(renderLines);
Object.values(tableEls).forEach((el) => ro.observe(el));
renderLines();

// Fit button
document.getElementById("fitBtn").addEventListener("click", () => {
  SCHEMA.forEach((t, i) => {
    const row = Math.floor(i / 3);
    const col = i % 3;
    positions[t.id] = { x: 40 + col * 260, y: 60 + row * 220 };
    tableEls[t.id].style.left = positions[t.id].x + "px";
    tableEls[t.id].style.top = positions[t.id].y + "px";
  });
  renderLines();
});

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>Schema Diagram</title>
  <link rel="stylesheet" href="style.css" />
</head>
<body>
<div class="demo">
  <div class="sd-toolbar">
    <span class="sd-title">E-Commerce Schema</span>
    <div class="sd-actions">
      <button class="sd-btn" id="fitBtn">Fit view</button>
      <span class="sd-hint">Drag tables to reposition</span>
    </div>
  </div>
  <div class="sd-canvas" id="sdCanvas">
    <svg class="sd-svg" id="sdSvg" width="100%" height="100%">
      <defs>
        <marker id="arrow" markerWidth="8" markerHeight="8" refX="6" refY="3" orient="auto">
          <path d="M0,0 L0,6 L8,3 z" fill="#9ca3af" />
        </marker>
      </defs>
      <!-- Relationship lines rendered by JS -->
      <g id="lines"></g>
    </svg>
    <!-- Table nodes rendered by JS -->
    <div id="tableContainer"></div>
  </div>
</div>
<script src="script.js"></script>
</body>
</html>

import { useState, useRef, useEffect, useCallback } from "react";

interface Column {
  name: string;
  type: string;
  pk?: boolean;
  fk?: boolean;
  nullable?: boolean;
}

interface Table {
  id: string;
  name: string;
  color: string;
  x: number;
  y: number;
  columns: Column[];
}

interface Relation {
  from: string; // tableId.columnName
  to: string;
  label?: string;
}

const TABLES: Table[] = [
  {
    id: "users",
    name: "users",
    color: "#58a6ff",
    x: 60,
    y: 80,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "email", type: "text", nullable: false },
      { name: "name", type: "text", nullable: true },
      { name: "role", type: "enum", nullable: false },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "posts",
    name: "posts",
    color: "#7ee787",
    x: 400,
    y: 60,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "user_id", type: "uuid", fk: true },
      { name: "title", type: "text" },
      { name: "body", type: "text", nullable: true },
      { name: "published", type: "bool" },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "comments",
    name: "comments",
    color: "#e3b341",
    x: 400,
    y: 330,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "post_id", type: "uuid", fk: true },
      { name: "user_id", type: "uuid", fk: true },
      { name: "body", type: "text" },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "tags",
    name: "tags",
    color: "#bc8cff",
    x: 720,
    y: 60,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "name", type: "text" },
      { name: "slug", type: "text" },
    ],
  },
  {
    id: "post_tags",
    name: "post_tags",
    color: "#ff7b72",
    x: 720,
    y: 280,
    columns: [
      { name: "post_id", type: "uuid", pk: true, fk: true },
      { name: "tag_id", type: "uuid", pk: true, fk: true },
    ],
  },
];

const RELATIONS: Relation[] = [
  { from: "posts.user_id", to: "users.id", label: "N:1" },
  { from: "comments.post_id", to: "posts.id", label: "N:1" },
  { from: "comments.user_id", to: "users.id", label: "N:1" },
  { from: "post_tags.post_id", to: "posts.id", label: "N:1" },
  { from: "post_tags.tag_id", to: "tags.id", label: "N:1" },
];

const TABLE_W = 200;
const ROW_H = 28;
const HEADER_H = 36;

function tableHeight(t: Table) {
  return HEADER_H + t.columns.length * ROW_H;
}

function colY(t: Table, colName: string) {
  const idx = t.columns.findIndex((c) => c.name === colName);
  return t.y + HEADER_H + idx * ROW_H + ROW_H / 2;
}

type Point = { x: number; y: number };

function bezierPath(a: Point, b: Point) {
  const cx = (a.x + b.x) / 2;
  return `M ${a.x} ${a.y} C ${cx} ${a.y}, ${cx} ${b.y}, ${b.x} ${b.y}`;
}

function RelationLine({
  fromTable,
  toTable,
  fromCol,
  toCol,
  label,
  active,
  animated,
}: {
  fromTable: Table;
  toTable: Table;
  fromCol: string;
  toCol: string;
  label?: string;
  active: boolean;
  animated: boolean;
}) {
  const fx = fromTable.x + TABLE_W;
  const fy = colY(fromTable, fromCol);
  const tx = toTable.x;
  const ty = colY(toTable, toCol);
  const path = bezierPath({ x: fx, y: fy }, { x: tx, y: ty });
  const mid = { x: (fx + tx) / 2, y: (fy + ty) / 2 };

  return (
    <g>
      <path
        d={path}
        fill="none"
        stroke={active ? "#58a6ff" : "#30363d"}
        strokeWidth={active ? 2 : 1.5}
        strokeDasharray={animated ? "6 3" : undefined}
        className={animated ? "animate-dash" : undefined}
        opacity={active ? 1 : 0.6}
      />
      {label && (
        <text
          x={mid.x}
          y={mid.y - 6}
          fill={active ? "#58a6ff" : "#484f58"}
          fontSize={10}
          textAnchor="middle"
          fontFamily="monospace"
        >
          {label}
        </text>
      )}
    </g>
  );
}

function TableNode({
  table,
  onDrag,
  selected,
  onClick,
}: {
  table: Table;
  onDrag: (id: string, dx: number, dy: number) => void;
  selected: boolean;
  onClick: (id: string) => void;
}) {
  const dragRef = useRef<{ startX: number; startY: number } | null>(null);

  const handleMouseDown = (e: React.MouseEvent) => {
    e.stopPropagation();
    dragRef.current = { startX: e.clientX, startY: e.clientY };
    const onMove = (me: MouseEvent) => {
      if (!dragRef.current) return;
      onDrag(table.id, me.clientX - dragRef.current.startX, me.clientY - dragRef.current.startY);
      dragRef.current = { startX: me.clientX, startY: me.clientY };
    };
    const onUp = () => {
      dragRef.current = null;
      window.removeEventListener("mousemove", onMove);
      window.removeEventListener("mouseup", onUp);
    };
    window.addEventListener("mousemove", onMove);
    window.addEventListener("mouseup", onUp);
    onClick(table.id);
  };

  const h = tableHeight(table);

  return (
    <g
      transform={`translate(${table.x}, ${table.y})`}
      onMouseDown={handleMouseDown}
      style={{ cursor: "grab" }}
    >
      {/* Shadow */}
      <rect x={3} y={3} width={TABLE_W} height={h} rx={8} fill="rgba(0,0,0,0.4)" />
      {/* Body */}
      <rect
        width={TABLE_W}
        height={h}
        rx={8}
        fill="#161b22"
        stroke={selected ? table.color : "#30363d"}
        strokeWidth={selected ? 2 : 1}
      />
      {/* Header */}
      <rect width={TABLE_W} height={HEADER_H} rx={8} fill={table.color + "22"} />
      <rect y={HEADER_H - 8} width={TABLE_W} height={8} fill={table.color + "22"} />
      <rect
        y={HEADER_H - 1}
        width={TABLE_W}
        height={1}
        fill={selected ? table.color : "#30363d"}
        opacity={0.6}
      />

      {/* Table name */}
      <text
        x={TABLE_W / 2}
        y={HEADER_H / 2 + 5}
        textAnchor="middle"
        fill={table.color}
        fontSize={13}
        fontWeight="bold"
        fontFamily="monospace"
      >
        {table.name}
      </text>

      {/* Columns */}
      {table.columns.map((col, i) => {
        const cy = HEADER_H + i * ROW_H;
        return (
          <g key={col.name}>
            {i % 2 === 1 && (
              <rect y={cy} width={TABLE_W} height={ROW_H} fill="rgba(255,255,255,0.02)" />
            )}
            {/* PK/FK indicator */}
            {(col.pk || col.fk) && (
              <text
                x={10}
                y={cy + ROW_H / 2 + 4}
                fill={col.pk ? "#e3b341" : "#bc8cff"}
                fontSize={9}
                fontFamily="monospace"
              >
                {col.pk ? "PK" : "FK"}
              </text>
            )}
            <text
              x={col.pk || col.fk ? 34 : 10}
              y={cy + ROW_H / 2 + 4}
              fill={col.nullable ? "#8b949e" : "#e6edf3"}
              fontSize={11}
              fontFamily="monospace"
            >
              {col.name}
            </text>
            <text
              x={TABLE_W - 8}
              y={cy + ROW_H / 2 + 4}
              textAnchor="end"
              fill="#484f58"
              fontSize={10}
              fontFamily="monospace"
            >
              {col.type}
            </text>
          </g>
        );
      })}
    </g>
  );
}

export default function SchemaDiagramRC() {
  const [tables, setTables] = useState(TABLES);
  const [selected, setSelected] = useState<string | null>(null);
  const [animated, setAnimated] = useState(true);

  const handleDrag = useCallback((id: string, dx: number, dy: number) => {
    setTables((prev) => prev.map((t) => (t.id === id ? { ...t, x: t.x + dx, y: t.y + dy } : t)));
  }, []);

  const canvasH = Math.max(...tables.map((t) => t.y + tableHeight(t))) + 80;
  const canvasW = Math.max(...tables.map((t) => t.x + TABLE_W)) + 80;

  return (
    <div className="min-h-screen bg-[#0d1117] p-6 flex flex-col items-center">
      <style>{`
        @keyframes dash { to { stroke-dashoffset: -18; } }
        .animate-dash { animation: dash 0.8s linear infinite; }
      `}</style>

      <div className="w-full max-w-[1000px] space-y-3">
        <div className="flex items-center justify-between">
          <h2 className="text-[15px] font-bold text-[#e6edf3]">Schema Diagram</h2>
          <div className="flex items-center gap-2">
            <span className="text-[11px] text-[#484f58]">Drag tables to reposition</span>
            <button
              onClick={() => setAnimated((v) => !v)}
              className={`px-2.5 py-1 rounded-lg text-[11px] font-semibold border transition-colors ${
                animated
                  ? "bg-[#58a6ff]/10 border-[#58a6ff]/30 text-[#58a6ff]"
                  : "border-[#30363d] text-[#8b949e] hover:text-[#e6edf3]"
              }`}
            >
              {animated ? "Animated" : "Static"}
            </button>
            <button
              onClick={() => setTables(TABLES)}
              className="px-2.5 py-1 rounded-lg text-[11px] border border-[#30363d] text-[#8b949e] hover:text-[#e6edf3] transition-colors"
            >
              Reset
            </button>
          </div>
        </div>

        <div className="bg-[#0d1117] border border-[#30363d] rounded-xl overflow-auto">
          <svg width={canvasW} height={canvasH} className="block" onClick={() => setSelected(null)}>
            {/* Grid */}
            <defs>
              <pattern id="grid" width="24" height="24" patternUnits="userSpaceOnUse">
                <path d="M 24 0 L 0 0 0 24" fill="none" stroke="#21262d" strokeWidth="0.5" />
              </pattern>
            </defs>
            <rect width="100%" height="100%" fill="url(#grid)" />

            {/* Relations (behind tables) */}
            {RELATIONS.map((rel) => {
              const [fid, fcol] = rel.from.split(".");
              const [tid, tcol] = rel.to.split(".");
              const ft = tables.find((t) => t.id === fid);
              const tt = tables.find((t) => t.id === tid);
              if (!ft || !tt) return null;
              const active = selected === fid || selected === tid;
              return (
                <RelationLine
                  key={rel.from}
                  fromTable={ft}
                  toTable={tt}
                  fromCol={fcol}
                  toCol={tcol}
                  label={rel.label}
                  active={active}
                  animated={animated}
                />
              );
            })}

            {/* Tables */}
            {tables.map((t) => (
              <TableNode
                key={t.id}
                table={t}
                onDrag={handleDrag}
                selected={selected === t.id}
                onClick={setSelected}
              />
            ))}
          </svg>
        </div>

        {/* Legend */}
        <div className="flex flex-wrap gap-4 text-[11px] text-[#8b949e]">
          <span className="flex items-center gap-1.5">
            <span className="font-mono font-bold text-[#e3b341]">PK</span> Primary key
          </span>
          <span className="flex items-center gap-1.5">
            <span className="font-mono font-bold text-[#bc8cff]">FK</span> Foreign key
          </span>
          <span className="flex items-center gap-1.5">
            <span className="w-6 h-px border-t-2 border-dashed border-[#30363d] inline-block" />{" "}
            Relation
          </span>
          <span className="flex items-center gap-1.5">
            <span className="w-6 h-px border-t-2 border-[#58a6ff] inline-block" /> Selected relation
          </span>
        </div>
      </div>
    </div>
  );
}

<script setup>
import { ref, computed } from "vue";

const TABLES_INIT = [
  {
    id: "users",
    name: "users",
    color: "#58a6ff",
    x: 60,
    y: 80,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "email", type: "text", nullable: false },
      { name: "name", type: "text", nullable: true },
      { name: "role", type: "enum", nullable: false },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "posts",
    name: "posts",
    color: "#7ee787",
    x: 400,
    y: 60,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "user_id", type: "uuid", fk: true },
      { name: "title", type: "text" },
      { name: "body", type: "text", nullable: true },
      { name: "published", type: "bool" },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "comments",
    name: "comments",
    color: "#e3b341",
    x: 400,
    y: 330,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "post_id", type: "uuid", fk: true },
      { name: "user_id", type: "uuid", fk: true },
      { name: "body", type: "text" },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "tags",
    name: "tags",
    color: "#bc8cff",
    x: 720,
    y: 60,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "name", type: "text" },
      { name: "slug", type: "text" },
    ],
  },
  {
    id: "post_tags",
    name: "post_tags",
    color: "#ff7b72",
    x: 720,
    y: 280,
    columns: [
      { name: "post_id", type: "uuid", pk: true, fk: true },
      { name: "tag_id", type: "uuid", pk: true, fk: true },
    ],
  },
];

const RELATIONS = [
  { from: "posts.user_id", to: "users.id", label: "N:1" },
  { from: "comments.post_id", to: "posts.id", label: "N:1" },
  { from: "comments.user_id", to: "users.id", label: "N:1" },
  { from: "post_tags.post_id", to: "posts.id", label: "N:1" },
  { from: "post_tags.tag_id", to: "tags.id", label: "N:1" },
];

const TABLE_W = 200;
const ROW_H = 28;
const HEADER_H = 36;

const tables = ref(TABLES_INIT.map((t) => ({ ...t })));
const selected = ref(null);
const animated = ref(true);

function tableHeight(t) {
  return HEADER_H + t.columns.length * ROW_H;
}

function colY(t, colName) {
  const idx = t.columns.findIndex((c) => c.name === colName);
  return t.y + HEADER_H + idx * ROW_H + ROW_H / 2;
}

function bezierPath(a, b) {
  const cx = (a.x + b.x) / 2;
  return `M ${a.x} ${a.y} C ${cx} ${a.y}, ${cx} ${b.y}, ${b.x} ${b.y}`;
}

const canvasH = computed(() => Math.max(...tables.value.map((t) => t.y + tableHeight(t))) + 80);
const canvasW = computed(() => Math.max(...tables.value.map((t) => t.x + TABLE_W)) + 80);

function getRelationData(rel) {
  const [fid, fcol] = rel.from.split(".");
  const [tid, tcol] = rel.to.split(".");
  const ft = tables.value.find((t) => t.id === fid);
  const tt = tables.value.find((t) => t.id === tid);
  if (!ft || !tt) return null;
  const fx = ft.x + TABLE_W;
  const fy = colY(ft, fcol);
  const tx = tt.x;
  const ty = colY(tt, tcol);
  const path = bezierPath({ x: fx, y: fy }, { x: tx, y: ty });
  const mid = { x: (fx + tx) / 2, y: (fy + ty) / 2 };
  const active = selected.value === fid || selected.value === tid;
  return { path, mid, label: rel.label, active };
}

function handleTableMouseDown(e, tableId) {
  e.stopPropagation();
  selected.value = tableId;
  let lastX = e.clientX;
  let lastY = e.clientY;

  const onMove = (me) => {
    const dx = me.clientX - lastX;
    const dy = me.clientY - lastY;
    lastX = me.clientX;
    lastY = me.clientY;
    tables.value = tables.value.map((t) =>
      t.id === tableId ? { ...t, x: t.x + dx, y: t.y + dy } : t
    );
  };

  const onUp = () => {
    window.removeEventListener("mousemove", onMove);
    window.removeEventListener("mouseup", onUp);
  };

  window.addEventListener("mousemove", onMove);
  window.addEventListener("mouseup", onUp);
}

function resetTables() {
  tables.value = TABLES_INIT.map((t) => ({ ...t }));
}
</script>

<template>
  <div style="min-height: 100vh; background: #0d1117; padding: 1.5rem; display: flex; flex-direction: column; align-items: center; font-family: system-ui, -apple-system, sans-serif;">
    <div style="width: 100%; max-width: 1000px; display: flex; flex-direction: column; gap: 0.75rem;">
      <div style="display: flex; align-items: center; justify-content: space-between;">
        <h2 style="font-size: 15px; font-weight: 700; color: #e6edf3;">Schema Diagram</h2>
        <div style="display: flex; align-items: center; gap: 0.5rem;">
          <span style="font-size: 11px; color: #484f58;">Drag tables to reposition</span>
          <button
            @click="animated = !animated"
            :style="{
              padding: '0.25rem 0.625rem',
              borderRadius: '0.5rem',
              fontSize: '11px',
              fontWeight: 600,
              border: `1px solid ${animated ? 'rgba(88,166,255,0.3)' : '#30363d'}`,
              background: animated ? 'rgba(88,166,255,0.1)' : 'transparent',
              color: animated ? '#58a6ff' : '#8b949e',
              cursor: 'pointer',
            }"
          >
            {{ animated ? "Animated" : "Static" }}
          </button>
          <button
            @click="resetTables"
            style="padding: 0.25rem 0.625rem; border-radius: 0.5rem; font-size: 11px; border: 1px solid #30363d; color: #8b949e; background: transparent; cursor: pointer;"
          >
            Reset
          </button>
        </div>
      </div>

      <div style="background: #0d1117; border: 1px solid #30363d; border-radius: 0.75rem; overflow: auto;">
        <svg
          :width="canvasW"
          :height="canvasH"
          style="display: block;"
          @click="selected = null"
        >
          <defs>
            <pattern id="grid" width="24" height="24" patternUnits="userSpaceOnUse">
              <path d="M 24 0 L 0 0 0 24" fill="none" stroke="#21262d" stroke-width="0.5" />
            </pattern>
          </defs>
          <rect width="100%" height="100%" fill="url(#grid)" />

          <template v-for="rel in RELATIONS" :key="rel.from">
            <g v-if="getRelationData(rel)">
              <path
                :d="getRelationData(rel).path"
                fill="none"
                :stroke="getRelationData(rel).active ? '#58a6ff' : '#30363d'"
                :stroke-width="getRelationData(rel).active ? 2 : 1.5"
                :stroke-dasharray="animated ? '6 3' : undefined"
                :class="animated ? 'animate-dash' : ''"
                :opacity="getRelationData(rel).active ? 1 : 0.6"
              />
              <text
                v-if="getRelationData(rel).label"
                :x="getRelationData(rel).mid.x"
                :y="getRelationData(rel).mid.y - 6"
                :fill="getRelationData(rel).active ? '#58a6ff' : '#484f58'"
                font-size="10"
                text-anchor="middle"
                font-family="monospace"
              >{{ getRelationData(rel).label }}</text>
            </g>
          </template>

          <g
            v-for="table in tables"
            :key="table.id"
            :transform="`translate(${table.x}, ${table.y})`"
            @mousedown="(e) => handleTableMouseDown(e, table.id)"
            style="cursor: grab;"
          >
            <rect x="3" y="3" :width="TABLE_W" :height="tableHeight(table)" rx="8" fill="rgba(0,0,0,0.4)" />
            <rect :width="TABLE_W" :height="tableHeight(table)" rx="8" fill="#161b22" :stroke="selected === table.id ? table.color : '#30363d'" :stroke-width="selected === table.id ? 2 : 1" />
            <rect :width="TABLE_W" :height="HEADER_H" rx="8" :fill="table.color + '22'" />
            <rect :y="HEADER_H - 8" :width="TABLE_W" height="8" :fill="table.color + '22'" />
            <rect :y="HEADER_H - 1" :width="TABLE_W" height="1" :fill="selected === table.id ? table.color : '#30363d'" opacity="0.6" />
            <text :x="TABLE_W / 2" :y="HEADER_H / 2 + 5" text-anchor="middle" :fill="table.color" font-size="13" font-weight="bold" font-family="monospace">{{ table.name }}</text>

            <g v-for="(col, i) in table.columns" :key="col.name">
              <rect v-if="i % 2 === 1" :y="HEADER_H + i * ROW_H" :width="TABLE_W" :height="ROW_H" fill="rgba(255,255,255,0.02)" />
              <text v-if="col.pk || col.fk" x="10" :y="HEADER_H + i * ROW_H + ROW_H / 2 + 4" :fill="col.pk ? '#e3b341' : '#bc8cff'" font-size="9" font-family="monospace">{{ col.pk ? "PK" : "FK" }}</text>
              <text :x="col.pk || col.fk ? 34 : 10" :y="HEADER_H + i * ROW_H + ROW_H / 2 + 4" :fill="col.nullable ? '#8b949e' : '#e6edf3'" font-size="11" font-family="monospace">{{ col.name }}</text>
              <text :x="TABLE_W - 8" :y="HEADER_H + i * ROW_H + ROW_H / 2 + 4" text-anchor="end" fill="#484f58" font-size="10" font-family="monospace">{{ col.type }}</text>
            </g>
          </g>
        </svg>
      </div>

      <div style="display: flex; flex-wrap: wrap; gap: 1rem; font-size: 11px; color: #8b949e;">
        <span style="display: flex; align-items: center; gap: 6px;">
          <span style="font-family: monospace; font-weight: 700; color: #e3b341;">PK</span> Primary key
        </span>
        <span style="display: flex; align-items: center; gap: 6px;">
          <span style="font-family: monospace; font-weight: 700; color: #bc8cff;">FK</span> Foreign key
        </span>
        <span style="display: flex; align-items: center; gap: 6px;">
          <span style="width: 24px; height: 1px; border-top: 2px dashed #30363d; display: inline-block;" /> Relation
        </span>
        <span style="display: flex; align-items: center; gap: 6px;">
          <span style="width: 24px; height: 1px; border-top: 2px solid #58a6ff; display: inline-block;" /> Selected
        </span>
      </div>
    </div>
  </div>
</template>

<style scoped>
@keyframes dash { to { stroke-dashoffset: -18; } }
.animate-dash { animation: dash 0.8s linear infinite; }
</style>

<script>
const TABLES_INIT = [
  {
    id: "users",
    name: "users",
    color: "#58a6ff",
    x: 60,
    y: 80,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "email", type: "text", nullable: false },
      { name: "name", type: "text", nullable: true },
      { name: "role", type: "enum", nullable: false },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "posts",
    name: "posts",
    color: "#7ee787",
    x: 400,
    y: 60,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "user_id", type: "uuid", fk: true },
      { name: "title", type: "text" },
      { name: "body", type: "text", nullable: true },
      { name: "published", type: "bool" },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "comments",
    name: "comments",
    color: "#e3b341",
    x: 400,
    y: 330,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "post_id", type: "uuid", fk: true },
      { name: "user_id", type: "uuid", fk: true },
      { name: "body", type: "text" },
      { name: "created_at", type: "timestamp" },
    ],
  },
  {
    id: "tags",
    name: "tags",
    color: "#bc8cff",
    x: 720,
    y: 60,
    columns: [
      { name: "id", type: "uuid", pk: true },
      { name: "name", type: "text" },
      { name: "slug", type: "text" },
    ],
  },
  {
    id: "post_tags",
    name: "post_tags",
    color: "#ff7b72",
    x: 720,
    y: 280,
    columns: [
      { name: "post_id", type: "uuid", pk: true, fk: true },
      { name: "tag_id", type: "uuid", pk: true, fk: true },
    ],
  },
];

const RELATIONS = [
  { from: "posts.user_id", to: "users.id", label: "N:1" },
  { from: "comments.post_id", to: "posts.id", label: "N:1" },
  { from: "comments.user_id", to: "users.id", label: "N:1" },
  { from: "post_tags.post_id", to: "posts.id", label: "N:1" },
  { from: "post_tags.tag_id", to: "tags.id", label: "N:1" },
];

const TABLE_W = 200;
const ROW_H = 28;
const HEADER_H = 36;

let tables = TABLES_INIT.map((t) => ({ ...t }));
let selected = null;
let animated = true;

function tableHeight(t) {
  return HEADER_H + t.columns.length * ROW_H;
}

function colY(t, colName) {
  const idx = t.columns.findIndex((c) => c.name === colName);
  return t.y + HEADER_H + idx * ROW_H + ROW_H / 2;
}

function bezierPath(a, b) {
  const cx = (a.x + b.x) / 2;
  return `M ${a.x} ${a.y} C ${cx} ${a.y}, ${cx} ${b.y}, ${b.x} ${b.y}`;
}

function getRelationPath(rel) {
  const [fid, fcol] = rel.from.split(".");
  const [tid, tcol] = rel.to.split(".");
  const ft = tables.find((t) => t.id === fid);
  const tt = tables.find((t) => t.id === tid);
  if (!ft || !tt) return null;
  const fx = ft.x + TABLE_W;
  const fy = colY(ft, fcol);
  const tx = tt.x;
  const ty = colY(tt, tcol);
  const path = bezierPath({ x: fx, y: fy }, { x: tx, y: ty });
  const mid = { x: (fx + tx) / 2, y: (fy + ty) / 2 };
  const active = selected === fid || selected === tid;
  return { path, mid, label: rel.label, active };
}

$: canvasH = Math.max(...tables.map((t) => t.y + tableHeight(t))) + 80;
$: canvasW = Math.max(...tables.map((t) => t.x + TABLE_W)) + 80;

function handleTableMouseDown(e, tableId) {
  e.stopPropagation();
  selected = tableId;
  const startX = e.clientX;
  const startY = e.clientY;

  const onMove = (me) => {
    const dx = me.clientX - startX;
    const dy = me.clientY - startY;
    tables = tables.map((t) =>
      t.id === tableId
        ? { ...t, x: t.x + (me.clientX - startX), y: t.y + (me.clientY - startY) }
        : t
    );
    // Update start for next delta
    Object.defineProperty(onMove, "_startX", { value: me.clientX, writable: true });
    Object.defineProperty(onMove, "_startY", { value: me.clientY, writable: true });
  };

  let lastX = e.clientX;
  let lastY = e.clientY;
  const onMoveTracked = (me) => {
    const dx = me.clientX - lastX;
    const dy = me.clientY - lastY;
    lastX = me.clientX;
    lastY = me.clientY;
    tables = tables.map((t) => (t.id === tableId ? { ...t, x: t.x + dx, y: t.y + dy } : t));
  };

  const onUp = () => {
    window.removeEventListener("mousemove", onMoveTracked);
    window.removeEventListener("mouseup", onUp);
  };

  window.addEventListener("mousemove", onMoveTracked);
  window.addEventListener("mouseup", onUp);
}

function resetTables() {
  tables = TABLES_INIT.map((t) => ({ ...t }));
}
</script>

<svelte:head>
  <style>
    @keyframes dash { to { stroke-dashoffset: -18; } }
    .animate-dash { animation: dash 0.8s linear infinite; }
  </style>
</svelte:head>

<div style="min-height: 100vh; background: #0d1117; padding: 1.5rem; display: flex; flex-direction: column; align-items: center; font-family: system-ui, -apple-system, sans-serif;">
  <div style="width: 100%; max-width: 1000px; display: flex; flex-direction: column; gap: 0.75rem;">
    <div style="display: flex; align-items: center; justify-content: space-between;">
      <h2 style="font-size: 15px; font-weight: 700; color: #e6edf3;">Schema Diagram</h2>
      <div style="display: flex; align-items: center; gap: 0.5rem;">
        <span style="font-size: 11px; color: #484f58;">Drag tables to reposition</span>
        <button
          on:click={() => (animated = !animated)}
          style="padding: 0.25rem 0.625rem; border-radius: 0.5rem; font-size: 11px; font-weight: 600; border: 1px solid {animated ? 'rgba(88,166,255,0.3)' : '#30363d'}; background: {animated ? 'rgba(88,166,255,0.1)' : 'transparent'}; color: {animated ? '#58a6ff' : '#8b949e'}; cursor: pointer;"
        >
          {animated ? "Animated" : "Static"}
        </button>
        <button
          on:click={resetTables}
          style="padding: 0.25rem 0.625rem; border-radius: 0.5rem; font-size: 11px; border: 1px solid #30363d; color: #8b949e; background: transparent; cursor: pointer;"
        >
          Reset
        </button>
      </div>
    </div>

    <div style="background: #0d1117; border: 1px solid #30363d; border-radius: 0.75rem; overflow: auto;">
      <svg
        width={canvasW}
        height={canvasH}
        style="display: block;"
        on:click={() => (selected = null)}
      >
        <defs>
          <pattern id="grid" width="24" height="24" patternUnits="userSpaceOnUse">
            <path d="M 24 0 L 0 0 0 24" fill="none" stroke="#21262d" stroke-width="0.5" />
          </pattern>
        </defs>
        <rect width="100%" height="100%" fill="url(#grid)" />

        {#each RELATIONS as rel}
          {@const r = getRelationPath(rel)}
          {#if r}
            <g>
              <path
                d={r.path}
                fill="none"
                stroke={r.active ? "#58a6ff" : "#30363d"}
                stroke-width={r.active ? 2 : 1.5}
                stroke-dasharray={animated ? "6 3" : undefined}
                class={animated ? "animate-dash" : ""}
                opacity={r.active ? 1 : 0.6}
              />
              {#if r.label}
                <text
                  x={r.mid.x}
                  y={r.mid.y - 6}
                  fill={r.active ? "#58a6ff" : "#484f58"}
                  font-size="10"
                  text-anchor="middle"
                  font-family="monospace"
                >{r.label}</text>
              {/if}
            </g>
          {/if}
        {/each}

        {#each tables as table}
          {@const h = tableHeight(table)}
          <g
            transform="translate({table.x}, {table.y})"
            on:mousedown={(e) => handleTableMouseDown(e, table.id)}
            style="cursor: grab;"
          >
            <rect x="3" y="3" width={TABLE_W} height={h} rx="8" fill="rgba(0,0,0,0.4)" />
            <rect width={TABLE_W} height={h} rx="8" fill="#161b22" stroke={selected === table.id ? table.color : "#30363d"} stroke-width={selected === table.id ? 2 : 1} />
            <rect width={TABLE_W} height={HEADER_H} rx="8" fill={table.color + "22"} />
            <rect y={HEADER_H - 8} width={TABLE_W} height="8" fill={table.color + "22"} />
            <rect y={HEADER_H - 1} width={TABLE_W} height="1" fill={selected === table.id ? table.color : "#30363d"} opacity="0.6" />
            <text x={TABLE_W / 2} y={HEADER_H / 2 + 5} text-anchor="middle" fill={table.color} font-size="13" font-weight="bold" font-family="monospace">{table.name}</text>

            {#each table.columns as col, i}
              {@const cy = HEADER_H + i * ROW_H}
              <g>
                {#if i % 2 === 1}
                  <rect y={cy} width={TABLE_W} height={ROW_H} fill="rgba(255,255,255,0.02)" />
                {/if}
                {#if col.pk || col.fk}
                  <text x="10" y={cy + ROW_H / 2 + 4} fill={col.pk ? "#e3b341" : "#bc8cff"} font-size="9" font-family="monospace">{col.pk ? "PK" : "FK"}</text>
                {/if}
                <text x={col.pk || col.fk ? 34 : 10} y={cy + ROW_H / 2 + 4} fill={col.nullable ? "#8b949e" : "#e6edf3"} font-size="11" font-family="monospace">{col.name}</text>
                <text x={TABLE_W - 8} y={cy + ROW_H / 2 + 4} text-anchor="end" fill="#484f58" font-size="10" font-family="monospace">{col.type}</text>
              </g>
            {/each}
          </g>
        {/each}
      </svg>
    </div>

    <div style="display: flex; flex-wrap: wrap; gap: 1rem; font-size: 11px; color: #8b949e;">
      <span style="display: flex; align-items: center; gap: 6px;">
        <span style="font-family: monospace; font-weight: 700; color: #e3b341;">PK</span> Primary key
      </span>
      <span style="display: flex; align-items: center; gap: 6px;">
        <span style="font-family: monospace; font-weight: 700; color: #bc8cff;">FK</span> Foreign key
      </span>
      <span style="display: flex; align-items: center; gap: 6px;">
        <span style="width: 24px; height: 1px; border-top: 2px dashed #30363d; display: inline-block;" /> Relation
      </span>
      <span style="display: flex; align-items: center; gap: 6px;">
        <span style="width: 24px; height: 1px; border-top: 2px solid #58a6ff; display: inline-block;" /> Selected
      </span>
    </div>
  </div>
</div>