# `PhoenixLiveCalendar.DayMarker`
[🔗](https://github.com/mdon/phoenix_live_calendar/blob/v0.5.0/lib/phoenix_live_calendar/day_marker.ex#L1)

Represents a date-level annotation — holidays, special hours, closures, notices.

Day markers are **not events**. They annotate the date itself rather than
occupying a time slot. They appear as visual indicators on the day cell
(background color, label, icon) and can span multiple days.

Use day markers for:
- Public holidays ("Christmas Day", "New Year")
- Special operating hours ("Winter hours: 10am-3pm")
- Office closures ("Office closed for renovation")
- Seasonal notices ("Peak season — limited availability")
- Custom date labels ("Payday", "Sprint 12 start")

Day markers can optionally override availability — e.g., a holiday marker
with `available: false` blocks booking, while a "reduced hours" marker with
custom `availability` windows allows booking within those reduced hours.

## Examples

    # Public holiday — fully closed
    %DayMarker{
      id: "xmas",
      label: "Christmas Day",
      start_date: ~D[2026-12-25],
      end_date: ~D[2026-12-26],
      type: :holiday,
      color: "bg-error/20",
      icon: "🎄",
      available: false
    }

    # Reduced hours — bookable within modified schedule
    %DayMarker{
      id: "winter-hours",
      label: "Winter Hours",
      start_date: ~D[2026-12-20],
      end_date: ~D[2027-01-05],
      type: :notice,
      color: "bg-info/10",
      description: "Reduced hours: 10am-3pm",
      availability: [
        %PhoenixLiveCalendar.Availability{
          days_of_week: [1, 2, 3, 4, 5],
          start_time: ~T[10:00:00],
          end_time: ~T[15:00:00]
        }
      ]
    }

    # Simple label
    %DayMarker{
      id: "payday",
      label: "Payday",
      start_date: ~D[2026-04-15],
      type: :label,
      color: "bg-success/10"
    }

    # Heatmap tint — cell background only, no corner label chip
    %DayMarker{
      id: "activity-2026-04-15",
      label: "42 minutes",
      start_date: ~D[2026-04-15],
      color: "bg-success/30",
      show_label: false
    }

## Styling

- `color` — cell background class. When set, it becomes the day cell's
  background (winning over the weekend/out-of-month tint; today/selected
  stay visible via an inset ring). When unset, the cell falls back to the
  type-based tint (`:holiday`/`:closure`/`:notice`/`:season`).
- `text_color` / `class` — applied to the corner label chip instead of the
  type-based chip colors. `class` is the chip background/extra classes,
  `text_color` the text class.
- `show_label` — set `false` (or `label: nil`) to render only the cell
  tint with no corner chip; ideal for heatmap-style markers.

All classes are the consumer's responsibility to make Tailwind-visible
(complete class names, no interpolation).

# `marker_type`

```elixir
@type marker_type() :: :holiday | :closure | :notice | :label | :season | :custom
```

# `t`

```elixir
@type t() :: %PhoenixLiveCalendar.DayMarker{
  availability: [PhoenixLiveCalendar.Availability.t()] | nil,
  available: boolean(),
  class: String.t() | nil,
  color: String.t() | nil,
  description: String.t() | nil,
  end_date: Date.t() | nil,
  extra: map(),
  icon: String.t() | nil,
  id: term(),
  label: String.t(),
  show_label: boolean(),
  start_date: Date.t(),
  text_color: String.t() | nil,
  type: marker_type()
}
```

# `chip_class`

```elixir
@spec chip_class(t()) :: [String.t() | nil] | String.t()
```

The classes for a marker's label chip: its own `class`/`text_color` when
either is set, else the type-based defaults.

# `covers_date?`

```elixir
@spec covers_date?(t(), Date.t()) :: boolean()
```

Returns whether this marker covers the given date.

# `custom_color`

```elixir
@spec custom_color([t()]) :: String.t() | nil
```

The first custom cell `color` among a day's markers, or `nil`.

# `dot`

```elixir
@spec dot([t()]) :: %{class: String.t(), title: String.t() | nil} | nil
```

The first `:dot`-style heatmap marker for a day, as
`%{class: intensity_class, title: label}` — or `nil`. Views render it as
a small corner/inline dot instead of a cell tint.

# `effective_end_date`

```elixir
@spec effective_end_date(t()) :: Date.t()
```

Returns the effective end date (exclusive). Defaults to start + 1 day.

# `group_by_date`

```elixir
@spec group_by_date([t()], [Date.t()]) :: %{required(Date.t()) => [t()]}
```

Groups markers by date for a list of dates. Returns `%{Date.t() => [t()]}`.

# `labeled`

```elixir
@spec labeled([t()]) :: [t()]
```

Markers that want a visible label chip (`show_label` and a non-nil label).

# `markers_for_date`

```elixir
@spec markers_for_date([t()], Date.t()) :: [t()]
```

Returns all markers that cover a given date from a list.

# `semantic_class`

```elixir
@spec semantic_class([t()]) :: String.t() | nil
```

The semantic hook class for a day's markers (`cal-day-holiday` /
`cal-day-closed` / `cal-day-notice` / `cal-day-season`), or `nil`.
Kept on the cell even when a custom color replaces the tint, so consumer
CSS/tests keying off it keep matching.

# `span_days`

```elixir
@spec span_days(t()) :: pos_integer()
```

Returns the number of days this marker spans.

# `type_tint`

```elixir
@spec type_tint([t()]) :: String.t() | nil
```

The type-based background tint for a day's markers, or `nil`.

---

*Consult [api-reference.md](api-reference.md) for complete listing*