# templater.py - template expansion for output

#

# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>

#

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

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

from i18n import _

import sys, os

import util, config, templatefilters

path = ['templates', '../templates']

stringify = templatefilters.stringify

def _flatten(thing):

    '''yield a single stream from a possibly nested set of iterators'''

    if isinstance(thing, str):

        yield thing

    elif not hasattr(thing, '__iter__'):

        if thing is not None:

            yield str(thing)

    else:

        for i in thing:

            if isinstance(i, str):

                yield i

            elif not hasattr(i, '__iter__'):

                if i is not None:

                    yield str(i)

            elif i is not None:

                for j in _flatten(i):

                    yield j

def parsestring(s, quoted=True):

    '''parse a string using simple c-like syntax.

    string must be in quotes if quoted is True.'''

    if quoted:

        if len(s) < 2 or s[0] != s[-1]:

            raise SyntaxError(_('unmatched quotes'))

        return s[1:-1].decode('string_escape')

    return s.decode('string_escape')

class engine(object):

    '''template expansion engine.

    template expansion works like this. a map file contains key=value

    pairs. if value is quoted, it is treated as string. otherwise, it

    is treated as name of template file.

    templater is asked to expand a key in map. it looks up key, and

    looks for strings like this: {foo}. it expands {foo} by looking up

    foo in map, and substituting it. expansion is recursive: it stops

    when there is no more {foo} to replace.

    expansion also allows formatting and filtering.

    format uses key to expand each item in list. syntax is

    {key%format}.

    filter uses function to transform value. syntax is

    {key|filter1|filter2|...}.'''

    def __init__(self, loader, filters={}, defaults={}):

        self._loader = loader

        self._filters = filters

        self._defaults = defaults

        self._cache = {}

    def process(self, t, mapping):

        '''Perform expansion. t is name of map element to expand.

        mapping contains added elements for use during expansion. Is a

        generator.'''

        return _flatten(self._process(self._load(t), mapping))

    def _load(self, t):

        '''load, parse, and cache a template'''

        if t not in self._cache:

            self._cache[t] = self._parse(self._loader(t))

        return self._cache[t]

    def _get(self, mapping, key):

        v = mapping.get(key)

        if v is None:

            v = self._defaults.get(key, '')

        if hasattr(v, '__call__'):

            v = v(**mapping)

        return v

    def _filter(self, mapping, parts):

        filters, val = parts

        x = self._get(mapping, val)

        for f in filters:

            x = f(x)

        return x

    def _format(self, mapping, args):

        key, parsed = args

        v = self._get(mapping, key)

        if not hasattr(v, '__iter__'):

            raise SyntaxError(_("error expanding '%s%%%s'")

                              % (key, format))

        lm = mapping.copy()

        for i in v:

            if isinstance(i, dict):

                lm.update(i)

                yield self._process(parsed, lm)

            else:

                # v is not an iterable of dicts, this happen when 'key'

                # has been fully expanded already and format is useless.

                # If so, return the expanded value.

                yield i

    def _parse(self, tmpl):

        '''preparse a template'''

        parsed = []

        pos, stop = 0, len(tmpl)

        while pos < stop:

            n = tmpl.find('{', pos)

            if n < 0:

                parsed.append((None, tmpl[pos:stop]))

                break

            if n > 0 and tmpl[n - 1] == '\\':

                # escaped

                parsed.append((None, tmpl[pos:n - 1] + "{"))

                pos = n + 1

                continue

            if n > pos:

                parsed.append((None, tmpl[pos:n]))

            pos = n

            n = tmpl.find('}', pos)

            if n < 0:

                # no closing

                parsed.append((None, tmpl[pos:stop]))

                break

            expr = tmpl[pos + 1:n]

            pos = n + 1

            if '%' in expr:

                key, t = expr.split('%')

                parsed.append((self._format, (key.strip(),

                                              self._load(t.strip()))))

            elif '|' in expr:

                parts = expr.split('|')

                val = parts[0].strip()

                try:

                    filters = [self._filters[f.strip()] for f in parts[1:]]

                except KeyError, i:

                    raise SyntaxError(_("unknown filter '%s'") % i[0])

                parsed.append((self._filter, (filters, val)))

            else:

                parsed.append((self._get, expr.strip()))

        return parsed

    def _process(self, parsed, mapping):

        '''Render a template. Returns a generator.'''

        for f, e in parsed:

            if f:

                yield f(mapping, e)

            else:

                yield e

engines = {'default': engine}

class templater(object):

    def __init__(self, mapfile, filters={}, defaults={}, cache={},

                 minchunk=1024, maxchunk=65536):

        '''set up template engine.

        mapfile is name of file to read map definitions from.

        filters is dict of functions. each transforms a value into another.

        defaults is dict of default map definitions.'''

        self.mapfile = mapfile or 'template'

        self.cache = cache.copy()

        self.map = {}

        self.base = (mapfile and os.path.dirname(mapfile)) or ''

        self.filters = templatefilters.filters.copy()

        self.filters.update(filters)

        self.defaults = defaults

        self.minchunk, self.maxchunk = minchunk, maxchunk

        self.engines = {}

        if not mapfile:

            return

        if not os.path.exists(mapfile):

            raise util.Abort(_('style not found: %s') % mapfile)

        conf = config.config()

        conf.read(mapfile)

        for key, val in conf[''].items():

            if val[0] in "'\"":

                try:

                    self.cache[key] = parsestring(val)

                except SyntaxError, inst:

                    raise SyntaxError('%s: %s' %

                                      (conf.source('', key), inst.args[0]))

            else:

                val = 'default', val

                if ':' in val[1]:

                    val = val[1].split(':', 1)

                self.map[key] = val[0], os.path.join(self.base, val[1])

    def __contains__(self, key):

        return key in self.cache or key in self.map

    def load(self, t):

        '''Get the template for the given template name. Use a local cache.'''

        if not t in self.cache:

            try:

                self.cache[t] = open(self.map[t][1]).read()

            except IOError, inst:

                raise IOError(inst.args[0], _('template file %s: %s') %

                              (self.map[t][1], inst.args[1]))

        return self.cache[t]

    def __call__(self, t, **mapping):

        ttype = t in self.map and self.map[t][0] or 'default'

        proc = self.engines.get(ttype)

        if proc is None:

            proc = engines[ttype](self.load, self.filters, self.defaults)

            self.engines[ttype] = proc

        stream = proc.process(t, mapping)

        if self.minchunk:

            stream = util.increasingchunks(stream, min=self.minchunk,

                                           max=self.maxchunk)

        return stream

def templatepath(name=None):

    '''return location of template file or directory (if no name).

    returns None if not found.'''

    normpaths = []

    # executable version (py2exe) doesn't support __file__

    if hasattr(sys, 'frozen'):

        module = sys.executable

    else:

        module = __file__

    for f in path:

        if f.startswith('/'):

            p = f

        else:

            fl = f.split('/')

            p = os.path.join(os.path.dirname(module), *fl)

        if name:

            p = os.path.join(p, name)

        if name and os.path.exists(p):

            return os.path.normpath(p)

        elif os.path.isdir(p):

            normpaths.append(os.path.normpath(p))

    return normpaths

def stylemap(styles, paths=None):

    """Return path to mapfile for a given style.

    Searches mapfile in the following locations:

    1. templatepath/style/map

    2. templatepath/map-style

    3. templatepath/map

    """

    if paths is None:

        paths = templatepath()

    elif isinstance(paths, str):

        paths = [paths]

    if isinstance(styles, str):

        styles = [styles]

    for style in styles:

        if not style:

            continue

        locations = [os.path.join(style, 'map'), 'map-' + style]

        locations.append('map')

        for path in paths:

            for location in locations:

                mapfile = os.path.join(path, location)

                if os.path.isfile(mapfile):

                    return style, mapfile

    raise RuntimeError("No hgweb templates found in %r" % paths)