from prosemirror.transform import Transform
from prosemirror.schema.basic import schema

# Create a document containing a single paragraph with the text "Hello, world!"
doc = schema.node("doc", {}, [
    schema.node("paragraph", {}, [
        schema.text("Hello, world!")
    ])
])

# Create a Transform which will be applied to the document.
tr = Transform(doc)

# Delete the text from position 3 to 5. Adds a ReplaceStep to the transform.
tr.delete(3, 5)

# Make the first three characters bold. Adds an AddMarkStep to the transform.
tr.add_mark(1, 4, schema.mark("strong"))

# This transform can be converted to JSON to be sent and applied elsewhere.
assert [step.to_json() for step in tr.steps] == [{
    'stepType': 'replace',
    'from': 3,
    'to': 5
}, {
    'stepType': 'addMark',
    'mark': {'type': 'strong', 'attrs': {}},
    'from': 1,
    'to': 4
}]

# The resulting document can also be converted to JSON.
assert tr.doc.to_json() == {
    'type': 'doc',
    'content': [{
        'type': 'paragraph',
        'content': [{
            'type': 'text',
            'marks': [{'type': 'strong', 'attrs': {}}],
            'text': 'Heo'
        }, {
            'type': 'text',
            'text': ', world!'
        }]
    }]
}