from pathlib import Path
from IPython.core.alias import Alias
from IPython.core.interactiveshell import InteractiveShell
from IPython.core.magic import MagicAlias
from IPython.utils.text import dedent, indent

shell = InteractiveShell.instance()
magics = shell.magics_manager.magics

def _strip_underline(line):
    chars = set(line.strip())
    if len(chars) == 1 and ("-" in chars or "=" in chars):
        return ""
    else:
        return line

def format_docstring(func):
    docstring = (func.__doc__ or "Undocumented").rstrip()
    docstring = indent(dedent(docstring))
    # Sphinx complains if indented bits have rst headings in, so strip out
    # any underlines in the docstring.
    lines = [_strip_underline(l) for l in docstring.splitlines()]
    return "\n".join(lines)

output = [
"Line magics",
"===========",
"",
]

# Case insensitive sort by name
def sortkey(s): return s[0].lower()

for name, func in sorted(magics["line"].items(), key=sortkey):
    if isinstance(func, Alias) or isinstance(func, MagicAlias):
        # Aliases are magics, but shouldn't be documented here
        # Also skip aliases to other magics
        continue
    output.extend([".. magic:: {}".format(name),
                   "",
                   format_docstring(func),
                   ""])

output.extend([
"Cell magics",
"===========",
"",
])

for name, func in sorted(magics["cell"].items(), key=sortkey):
    if name == "!":
        # Special case - don't encourage people to use %%!
        continue
    if func == magics["line"].get(name, "QQQP"):
        # Don't redocument line magics that double as cell magics
        continue
    if isinstance(func, MagicAlias):
        continue
    output.extend([".. cellmagic:: {}".format(name),
                   "",
                   format_docstring(func),
                   ""])

src_path = Path(__file__).parent
dest = src_path.joinpath("source", "interactive", "magics-generated.txt")
dest.write_text("\n".join(output), encoding="utf-8")
