# 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, incorporated herein by reference.

from i18n import _

import re, sys, os

import util, config, templatefilters

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

stringify = templatefilters.stringify

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|...}.'''

    template_re = re.compile(r'{([\w\|%]+)}|#([\w\|%]+)#')

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

        self.loader = loader

        self.filters = filters

        self.defaults = defaults

        self.cache = {}

    def process(self, t, map):

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

        added elements for use during expansion. Is a generator.'''

        tmpl = self.loader(t)

        iters = [self._process(tmpl, map)]

        while iters:

            try:

                item = iters[0].next()

            except StopIteration:

                iters.pop(0)

                continue

            if isinstance(item, str):

                yield item

            elif item is None:

                yield ''

            elif hasattr(item, '__iter__'):

                iters.insert(0, iter(item))

            else:

                yield str(item)

    def _format(self, expr, get, map):

        key, format = expr.split('%')

        v = get(key)

        if not hasattr(v, '__iter__'):

            raise SyntaxError(_("error expanding '%s%%%s'") % (key, format))

        lm = map.copy()

        for i in v:

            lm.update(i)

            yield self.process(format, lm)

    def _filter(self, expr, get, map):

        if expr not in self.cache:

            parts = expr.split('|')

            val = parts[0]

            try:

                filters = [self.filters[f] for f in parts[1:]]

            except KeyError, i:

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

            def apply(get):

                    x = get(val)

                    for f in filters:

                        x = f(x)

                    return x

            self.cache[expr] = apply

        return self.cache[expr](get)

    def _process(self, tmpl, map):

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

        def get(key):

            v = map.get(key)

            if v is None:

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

            if hasattr(v, '__call__'):

                v = v(**map)

            return v

        while tmpl:

            m = self.template_re.search(tmpl)

            if not m:

                yield tmpl

                break

            start, end = m.span(0)

            variants = m.groups()

            expr = variants[0] or variants[1]

            if start:

                yield tmpl[:start]

            tmpl = tmpl[end:]

            if '%' in expr:

                yield self._format(expr, get, map)

            elif '|' in expr:

                yield self._filter(expr, get, map)

            else:

                yield get(expr)

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, **map):

        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, map)

        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(style, 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]

    locations = style and [os.path.join(style, "map"), "map-" + style] or []

    locations.append("map")

    for path in paths:

        for location in locations:

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

            if os.path.isfile(mapfile):

                return mapfile

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