# Code dedicated to display and exploration of the obsolescence history
#
# This module content aims at being upstreamed enventually.
#
# Copyright 2017 Octobus SAS <contact@octobus.net>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from mercurial import (
    node as nodemod,
)

def _debugobshistorysingle(fm, repo, revs):
    """ Display the obsolescence history for a single revision
    """
    precursors = repo.obsstore.precursors
    successors = repo.obsstore.successors
    nodec = repo.changelog.node
    nodes = [nodec(r) for r in revs]

    seen = set(nodes)

    while nodes:
        ctxnode = nodes.pop()

        _debugobshistorydisplaynode(fm, repo, ctxnode)

        succs = successors.get(ctxnode, ())

        markerfm = fm.nested("debugobshistory.markers")
        for successor in sorted(succs):
            _debugobshistorydisplaymarker(markerfm, repo, successor)
        markerfm.end()

        precs = precursors.get(ctxnode, ())
        for p in sorted(precs):
            # Only show nodes once
            if p[0] not in seen:
                seen.add(p[0])
                nodes.append(p[0])

def _debugobshistorydisplaynode(fm, repo, node):
    if node in repo.unfiltered():
        _debugobshistorydisplayctx(fm, repo.unfiltered()[node])
    else:
        _debugobshistorydisplaymissingctx(fm, node)

def _debugobshistorydisplayctx(fm, ctx):
    shortdescription = ctx.description().splitlines()[0]

    fm.startitem()
    fm.write('debugobshistory.node', '%s', str(ctx),
             label="evolve.node")
    fm.plain(' ')

    fm.write('debugobshistory.rev', '(%d)', int(ctx),
             label="evolve.rev")
    fm.plain(' ')

    fm.write('debugobshistory.shortdescription', '%s', shortdescription,
             label="evolve.short_description")
    fm.plain('\n')

def _debugobshistorydisplaymissingctx(fm, nodewithoutctx):
    hexnode = nodemod.short(nodewithoutctx)
    fm.startitem()
    fm.write('debugobshistory.node', '%s', hexnode,
             label="evolve.node evolve.missing_change_ctx")
    fm.plain('\n')

def _debugobshistorydisplaymarker(fm, repo, marker):
    succnodes = marker[1]
    date = marker[4]
    metadata = dict(marker[3])

    fm.startitem()
    fm.plain('  ')

    # Detect pruned revisions
    if len(succnodes) == 0:
        verb = 'pruned'
    else:
        verb = 'rewritten'

    fm.write('debugobshistory.verb', '%s', verb,
             label="evolve.verb")
    fm.plain(' by ')

    fm.write('debugobshistory.marker_user', '%s', metadata['user'],
             label="evolve.user")
    fm.plain(' ')

    fm.write('debugobshistory.marker_date', '(%s)', fm.formatdate(date),
             label="evolve.date")

    if len(succnodes) > 0:
        fm.plain(' as ')

        shortsnodes = (nodemod.short(succnode) for succnode in sorted(succnodes))
        nodes = fm.formatlist(shortsnodes, 'debugobshistory.succnodes', sep=', ')
        fm.write('debugobshistory.succnodes', '%s', nodes,
                 label="evolve.node")

    fm.plain("\n")