# PrintoutYourWorkout — LLM Usage Guide

## What this app does

PrintoutYourWorkout is a no-backend, no-login workout plan builder. Users
compose a weekly workout schedule (exercises, sets, reps, days), then share or
bookmark it via a single URL. There is no server, no database, and no
authentication — the entire workout is encoded in the URL itself.

Live at: https://www.printoutyourworkout.com/

---

## URL schema

A shareable workout is passed as a single query parameter:

    https://www.printoutyourworkout.com/?workout=<encoded>

The `<encoded>` value is produced by this pipeline:

    JSON  →  zlib deflate (pako)  →  base64  →  URL-encode

To decode, reverse the pipeline:

    URL-decode  →  base64 decode  →  zlib inflate  →  JSON parse

---

## JSON data structure

The JSON value is an array of exactly 7 elements, one per day of the week,
indexed Monday (0) through Sunday (6).

Each element is either `null` (no exercises planned that day) or an object:

```json
[
  {
    "day": "Monday",
    "exercises": [
      { "id": 1700000000000, "name": "Bench Press", "sets": 3, "reps": 10 },
      { "id": 1700000000001, "name": "Push-up",     "sets": 4, "reps": 15 }
    ]
  },
  null,
  {
    "day": "Wednesday",
    "exercises": [
      { "id": 1700000000002, "name": "Squat", "sets": 4, "reps": 8 }
    ]
  },
  null,
  null,
  null,
  null
]
```

### Field reference

| Field              | Type   | Notes                                           |
|--------------------|--------|-------------------------------------------------|
| `day`              | string | Full English day name ("Monday" … "Sunday")     |
| `exercises[].id`   | number | Unix timestamp (ms). Any unique integer is fine |
| `exercises[].name` | string | Exercise name (free text)                       |
| `exercises[].sets` | number | Number of sets                                  |
| `exercises[].reps` | number | Number of reps per set                          |

---

## Python example

```python
import json, zlib, base64, urllib.parse

def build_workout_url(workout: list, base: str = "https://www.printoutyourworkout.com/") -> str:
    json_bytes  = json.dumps(workout, separators=(",", ":")).encode("utf-8")
    compressed  = zlib.compress(json_bytes, level=6, wbits=-15)  # raw deflate (no zlib header)
    b64         = base64.b64encode(compressed).decode("ascii")
    encoded     = urllib.parse.quote(b64, safe="")
    return f"{base}?workout={encoded}"


workout = [
    {
        "day": "Monday",
        "exercises": [
            {"id": 1700000000000, "name": "Bench Press", "sets": 3, "reps": 10},
            {"id": 1700000000001, "name": "Push-up",     "sets": 4, "reps": 15},
        ],
    },
    None,  # Tuesday — rest day
    {
        "day": "Wednesday",
        "exercises": [
            {"id": 1700000000002, "name": "Squat", "sets": 4, "reps": 8},
        ],
    },
    None, None, None, None,  # Thu–Sun — rest days
]

print(build_workout_url(workout))
```

> **Note on deflate:** pako's `deflate()` (used by the app) produces *raw*
> deflate without a zlib wrapper. Pass `wbits=-15` to Python's `zlib.compress`
> to match that format.

---

## Node.js example

```js
import { deflateRawSync } from "node:zlib";

function buildWorkoutUrl(workout, base = "https://www.printoutyourworkout.com/") {
  const json       = JSON.stringify(workout);
  const input      = Buffer.from(json, "utf8");
  const compressed = deflateRawSync(input, { level: 6 });
  const b64        = compressed.toString("base64");
  const encoded    = encodeURIComponent(b64);
  return `${base}?workout=${encoded}`;
}

const workout = [
  {
    day: "Monday",
    exercises: [
      { id: 1700000000000, name: "Bench Press", sets: 3, reps: 10 },
      { id: 1700000000001, name: "Push-up",     sets: 4, reps: 15 },
    ],
  },
  null, // Tuesday — rest day
  {
    day: "Wednesday",
    exercises: [
      { id: 1700000000002, name: "Squat", sets: 4, reps: 8 },
    ],
  },
  null, null, null, null, // Thu–Sun — rest days
];

console.log(buildWorkoutUrl(workout));
```

> **Note:** `deflateRawSync` produces raw deflate (no zlib header), which
> matches what pako emits in the browser.