# drawdag.py - convert ASCII revision DAG to actual changesets

#

# Copyright 2016 Facebook, Inc.

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

"""

create changesets from an ASCII graph for testing purpose.

For example, given the following input::

    c d

    |/

    b

    |

    a

4 changesets and 4 local tags will be created.

`hg log -G -T "{rev} {desc} (tag: {tags})"` will output::

    o  3 d (tag: d tip)

    |

    | o  2 c (tag: c)

    |/

    o  1 b (tag: b)

    |

    o  0 a (tag: a)

For root nodes (nodes without parents) in the graph, they can be revsets

pointing to existing nodes.  The ASCII graph could also have disconnected

components with same names referring to the same changeset.

Therefore, given the repo having the 4 changesets (and tags) above, with the

following ASCII graph as input::

    foo    bar       bar  foo

     |     /          |    |

    ancestor(c,d)     a   baz

The result (`hg log -G -T "{desc}"`) will look like::

    o    foo

    |\

    +---o  bar

    | | |

    | o |  baz

    |  /

    +---o  d

    | |

    +---o  c

    | |

    o |  b

    |/

    o  a

Note that if you take the above `hg log` output directly as input. It will work

as expected - the result would be an isomorphic graph::

    o    foo

    |\

    | | o  d

    | |/

    | | o  c

    | |/

    | | o  bar

    | |/|

    | o |  b

    | |/

    o /  baz

     /

    o  a

This is because 'o' is specially handled in the input: instead of using 'o' as

the node name, the word to the right will be used.

"""

from __future__ import absolute_import, print_function

import collections

import itertools

from mercurial.i18n import _

from mercurial import (

    context,

    error,

    node,

    registrar,

    scmutil,

    tags as tagsmod,

)

cmdtable = {}

command = registrar.command(cmdtable)

_pipechars = '\\/+-|'

_nonpipechars = ''.join(chr(i) for i in xrange(33, 127)

                        if chr(i) not in _pipechars)

def _isname(ch):

    """char -> bool. return True if ch looks like part of a name, False

    otherwise"""

    return ch in _nonpipechars

def _parseasciigraph(text):

    """str -> {str : [str]}. convert the ASCII graph to edges"""

    lines = text.splitlines()

    edges = collections.defaultdict(list)  # {node: []}

    def get(y, x):

        """(int, int) -> char. give a coordinate, return the char. return a

        space for anything out of range"""

        if x < 0 or y < 0:

            return ' '

        try:

            return lines[y][x]

        except IndexError:

            return ' '

    def getname(y, x):

        """(int, int) -> str. like get(y, x) but concatenate left and right

        parts. if name is an 'o', try to replace it to the right"""

        result = ''

        for i in itertools.count(0):

            ch = get(y, x - i)

            if not _isname(ch):

                break

            result = ch + result

        for i in itertools.count(1):

            ch = get(y, x + i)

            if not _isname(ch):

                break

            result += ch

        if result == 'o':

            # special handling, find the name to the right

            result = ''

            for i in itertools.count(2):

                ch = get(y, x + i)

                if ch == ' ' or ch in _pipechars:

                    if result or x + i >= len(lines[y]):

                        break

                else:

                    result += ch

            return result or 'o'

        return result

    def parents(y, x):

        """(int, int) -> [str]. follow the ASCII edges at given position,

        return a list of parents"""

        visited = {(y, x)}

        visit = []

        result = []

        def follow(y, x, expected):

            """conditionally append (y, x) to visit array, if it's a char

            in excepted. 'o' in expected means an '_isname' test.

            if '-' (or '+') is not in excepted, and get(y, x) is '-' (or '+'),

            the next line (y + 1, x) will be checked instead."""

            ch = get(y, x)

            if any(ch == c and c not in expected for c in '-+'):

                y += 1

                return follow(y + 1, x, expected)

            if ch in expected or ('o' in expected and _isname(ch)):

                visit.append((y, x))

        #  -o-  # starting point:

        #  /|\ # follow '-' (horizontally), and '/|\' (to the bottom)

        follow(y + 1, x, '|')

        follow(y + 1, x - 1, '/')

        follow(y + 1, x + 1, '\\')

        follow(y, x - 1, '-')

        follow(y, x + 1, '-')

        while visit:

            y, x = visit.pop()

            if (y, x) in visited:

                continue

            visited.add((y, x))

            ch = get(y, x)

            if _isname(ch):

                result.append(getname(y, x))

                continue

            elif ch == '|':

                follow(y + 1, x, '/|o')

                follow(y + 1, x - 1, '/')

                follow(y + 1, x + 1, '\\')

            elif ch == '+':

                follow(y, x - 1, '-')

                follow(y, x + 1, '-')

                follow(y + 1, x - 1, '/')

                follow(y + 1, x + 1, '\\')

                follow(y + 1, x, '|')

            elif ch == '\\':

                follow(y + 1, x + 1, '\\|o')

            elif ch == '/':

                follow(y + 1, x - 1, '/|o')

            elif ch == '-':

                follow(y, x - 1, '-+o')

                follow(y, x + 1, '-+o')

        return result

    for y, line in enumerate(lines):

        for x, ch in enumerate(line):

            if ch == '#':  # comment

                break

            if _isname(ch):

                edges[getname(y, x)] += parents(y, x)

    return dict(edges)

class simplefilectx(object):

    def __init__(self, path, data):

        self._data = data

        self._path = path

    def data(self):

        return self._data

    def filenode(self):

        return None

    def path(self):

        return self._path

    def renamed(self):

        return None

    def flags(self):

        return ''

class simplecommitctx(context.committablectx):

    def __init__(self, repo, name, parentctxs, added=None):

        opts = {

            'changes': scmutil.status([], added or [], [], [], [], [], []),

            'date': '0 0',

            'extra': {'branch': 'default'},

        }

        super(simplecommitctx, self).__init__(self, name, **opts)

        self._repo = repo

        self._name = name

        self._parents = parentctxs

        self._parents.sort(key=lambda c: c.node())

        while len(self._parents) < 2:

            self._parents.append(repo[node.nullid])

    def filectx(self, key):

        return simplefilectx(key, self._name)

    def commit(self):

        return self._repo.commitctx(self)

def _walkgraph(edges):

    """yield node, parents in topologically order"""

    visible = set(edges.keys())

    remaining = {}  # {str: [str]}

    for k, vs in edges.iteritems():

        for v in vs:

            if v not in remaining:

                remaining[v] = []

        remaining[k] = vs[:]

    while remaining:

        leafs = [k for k, v in remaining.items() if not v]

        if not leafs:

            raise error.Abort(_('the graph has cycles'))

        for leaf in sorted(leafs):

            if leaf in visible:

                yield leaf, edges[leaf]

            del remaining[leaf]

            for k, v in remaining.iteritems():

                if leaf in v:

                    v.remove(leaf)

@command('debugdrawdag', [])

def debugdrawdag(ui, repo, **opts):

    """read an ASCII graph from stdin and create changesets

    The ASCII graph is like what :hg:`log -G` outputs, with each `o` replaced

    to the name of the node. The command will create dummy changesets and local

    tags with those names to make the dummy changesets easier to be referred

    to.

    If the name of a node is a single character 'o', It will be replaced by the

    word to the right. This makes it easier to reuse

    :hg:`log -G -T '{desc}'` outputs.

    For root (no parents) nodes, revset can be used to query existing repo.

    Note that the revset cannot have confusing characters which can be seen as

    the part of the graph edges, like `|/+-\`.

    """

    text = ui.fin.read()

    # parse the graph and make sure len(parents) <= 2 for each node

    edges = _parseasciigraph(text)

    for k, v in edges.iteritems():

        if len(v) > 2:

            raise error.Abort(_('%s: too many parents: %s')

                              % (k, ' '.join(v)))

    committed = {None: node.nullid}  # {name: node}

    # for leaf nodes, try to find existing nodes in repo

    for name, parents in edges.iteritems():

        if len(parents) == 0:

            try:

                committed[name] = scmutil.revsingle(repo, name)

            except error.RepoLookupError:

                pass

    # commit in topological order

    for name, parents in _walkgraph(edges):

        if name in committed:

            continue

        pctxs = [repo[committed[n]] for n in parents]

        ctx = simplecommitctx(repo, name, pctxs, [name])

        n = ctx.commit()

        committed[name] = n

        tagsmod.tag(repo, name, n, message=None, user=None, date=None,

                    local=True)