Migrate formatting_html.py into xarray core (#8930)

* DAS-2066: formatting_html.py merge

* Revert "DAS-2066: formatting_html.py merge"
oopsies
This reverts commit d68ae3c.

* Adding datatree functions to core

* Deleted formatting_html.py and test_formatting_html.py in datatree_

* renamed all of the relevant functions so they represent datatree

* added comment for mypy

* added dict[any, any] as type hint for children

* added dict[Any, Any] as type hint for children

* updated typhint to dict[str, DataTree] and increased pixel min width to 700

* replaced Any with DataTree

* added type checking

* DAS-2066 - Incorporate CSS changes for DataTree display.

* DAS-2066 - Fix tests.

---------

Co-authored-by: Owen Littlejohns <owen.m.littlejohns@nasa.gov>
Co-authored-by: Matt Savoie <matthew.savoie@colorado.edu>

doc/whats-new.rst

@@ -40,6 +40,9 @@ Bug fixes
 
 Internal Changes
 ~~~~~~~~~~~~~~~~
+- Migrates ``formatting_html`` functionality for `DataTree` into ``xarray/core`` (:pull: `8930`)
+  By `Eni Awowale <https://github.com/eni-awowale>`_, `Julia Signell <https://github.com/jsignell>`_
+  and `Tom Nicholas <https://github.com/TomNicholas>`_.
 - Migrates ``datatree_mapping`` functionality into ``xarray/core`` (:pull:`8948`)
   By `Matt Savoie <https://github.com/flamingbear>`_ `Owen Littlejohns
   <https://github.com/owenlittlejohns>` and `Tom Nicholas <https://github.com/TomNicholas>`_.

xarray/core/datatree.py

@@ -23,6 +23,9 @@
     check_isomorphic,
     map_over_subtree,
 )
+from xarray.core.formatting_html import (
+    datatree_repr as datatree_repr_html,
+)
 from xarray.core.indexes import Index, Indexes
 from xarray.core.merge import dataset_update_method
 from xarray.core.options import OPTIONS as XR_OPTS
@@ -38,9 +41,6 @@
 from xarray.core.variable import Variable
 from xarray.datatree_.datatree.common import TreeAttrAccessMixin
 from xarray.datatree_.datatree.formatting import datatree_repr
-from xarray.datatree_.datatree.formatting_html import (
-    datatree_repr as datatree_repr_html,
-)
 from xarray.datatree_.datatree.ops import (
     DataTreeArithmeticMixin,
     MappedDatasetMethodsMixin,

xarray/core/formatting_html.py

@@ -2,9 +2,11 @@
 
 import uuid
 from collections import OrderedDict
+from collections.abc import Mapping
 from functools import lru_cache, partial
 from html import escape
 from importlib.resources import files
+from typing import TYPE_CHECKING
 
 from xarray.core.formatting import (
     inline_index_repr,
@@ -18,6 +20,9 @@
     ("xarray.static.css", "style.css"),
 )
 
+if TYPE_CHECKING:
+    from xarray.core.datatree import DataTree
+
 
 @lru_cache(None)
 def _load_static_files():
@@ -341,3 +346,129 @@ def dataset_repr(ds) -> str:
     ]
 
     return _obj_repr(ds, header_components, sections)
+
+
+def summarize_datatree_children(children: Mapping[str, DataTree]) -> str:
+    N_CHILDREN = len(children) - 1
+
+    # Get result from datatree_node_repr and wrap it
+    lines_callback = lambda n, c, end: _wrap_datatree_repr(
+        datatree_node_repr(n, c), end=end
+    )
+
+    children_html = "".join(
+        (
+            lines_callback(n, c, end=False)  # Long lines
+            if i < N_CHILDREN
+            else lines_callback(n, c, end=True)
+        )  # Short lines
+        for i, (n, c) in enumerate(children.items())
+    )
+
+    return "".join(
+        [
+            "<div style='display: inline-grid; grid-template-columns: 100%; grid-column: 1 / -1'>",
+            children_html,
+            "</div>",
+        ]
+    )
+
+
+children_section = partial(
+    _mapping_section,
+    name="Groups",
+    details_func=summarize_datatree_children,
+    max_items_collapse=1,
+    expand_option_name="display_expand_groups",
+)
+
+
+def datatree_node_repr(group_title: str, dt: DataTree) -> str:
+    header_components = [f"<div class='xr-obj-type'>{escape(group_title)}</div>"]
+
+    ds = dt.ds
+
+    sections = [
+        children_section(dt.children),
+        dim_section(ds),
+        coord_section(ds.coords),
+        datavar_section(ds.data_vars),
+        attr_section(ds.attrs),
+    ]
+
+    return _obj_repr(ds, header_components, sections)
+
+
+def _wrap_datatree_repr(r: str, end: bool = False) -> str:
+    """
+    Wrap HTML representation with a tee to the left of it.
+
+    Enclosing HTML tag is a <div> with :code:`display: inline-grid` style.
+
+    Turns:
+    [    title    ]
+    |   details   |
+    |_____________|
+
+    into (A):
+    |─ [    title    ]
+    |  |   details   |
+    |  |_____________|
+
+    or (B):
+    └─ [    title    ]
+       |   details   |
+       |_____________|
+
+    Parameters
+    ----------
+    r: str
+        HTML representation to wrap.
+    end: bool
+        Specify if the line on the left should continue or end.
+
+        Default is True.
+
+    Returns
+    -------
+    str
+        Wrapped HTML representation.
+
+        Tee color is set to the variable :code:`--xr-border-color`.
+    """
+    # height of line
+    end = bool(end)
+    height = "100%" if end is False else "1.2em"
+    return "".join(
+        [
+            "<div style='display: inline-grid; grid-template-columns: 0px 20px auto; width: 100%;'>",
+            "<div style='",
+            "grid-column-start: 1;",
+            "border-right: 0.2em solid;",
+            "border-color: var(--xr-border-color);",
+            f"height: {height};",
+            "width: 0px;",
+            "'>",
+            "</div>",
+            "<div style='",
+            "grid-column-start: 2;",
+            "grid-row-start: 1;",
+            "height: 1em;",
+            "width: 20px;",
+            "border-bottom: 0.2em solid;",
+            "border-color: var(--xr-border-color);",
+            "'>",
+            "</div>",
+            "<div style='",
+            "grid-column-start: 3;",
+            "'>",
+            r,
+            "</div>",
+            "</div>",
+        ]
+    )
+
+
+def datatree_repr(dt: DataTree) -> str:
+    obj_type = f"datatree.{type(dt).__name__}"
+    return datatree_node_repr(obj_type, dt)