# 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 util, config, templatefilters, parser, error

# template parsing

elements = {

    "(": (20, ("group", 1, ")"), ("func", 1, ")")),

    ",": (2, None, ("list", 2)),

    "|": (5, None, ("|", 5)),

    "%": (6, None, ("%", 6)),

    ")": (0, None, None),

    "symbol": (0, ("symbol",), None),

    "string": (0, ("string",), None),

    "end": (0, None, None),

}

def tokenizer(data):

    program, start, end = data

    pos = start

    while pos < end:

        c = program[pos]

        if c.isspace(): # skip inter-token whitespace

            pass

        elif c in "(,)%|": # handle simple operators

            yield (c, None, pos)

        elif (c in '"\'' or c == 'r' and

              program[pos:pos + 2] in ("r'", 'r"')): # handle quoted strings

            if c == 'r':

                pos += 1

                c = program[pos]

                decode = False

            else:

                decode = True

            pos += 1

            s = pos

            while pos < end: # find closing quote

                d = program[pos]

                if decode and d == '\\': # skip over escaped characters

                    pos += 2

                    continue

                if d == c:

                    if not decode:

                        yield ('string', program[s:pos].replace('\\', r'\\'), s)

                        break

                    yield ('string', program[s:pos].decode('string-escape'), s)

                    break

                pos += 1

            else:

                raise error.ParseError(_("unterminated string"), s)

        elif c.isalnum() or c in '_':

            s = pos

            pos += 1

            while pos < end: # find end of symbol

                d = program[pos]

                if not (d.isalnum() or d == "_"):

                    break

                pos += 1

            sym = program[s:pos]

            yield ('symbol', sym, s)

            pos -= 1

        elif c == '}':

            pos += 1

            break

        else:

            raise error.ParseError(_("syntax error"), pos)

        pos += 1

    yield ('end', None, pos)

def compiletemplate(tmpl, context):

    parsed = []

    pos, stop = 0, len(tmpl)

    p = parser.parser(tokenizer, elements)

    while pos < stop:

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

        if n < 0:

            parsed.append(("string", tmpl[pos:]))

            break

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

            # escaped

            parsed.append(("string", tmpl[pos:n - 1] + "{"))

            pos = n + 1

            continue

        if n > pos:

            parsed.append(("string", tmpl[pos:n]))

        pd = [tmpl, n + 1, stop]

        parseres, pos = p.parse(pd)

        parsed.append(parseres)

    return [compileexp(e, context) for e in parsed]

def compileexp(exp, context):

    t = exp[0]

    if t in methods:

        return methods[t](exp, context)

    raise error.ParseError(_("unknown method '%s'") % t)

# template evaluation

def getsymbol(exp):

    if exp[0] == 'symbol':

        return exp[1]

    raise error.ParseError(_("expected a symbol"))

def getlist(x):

    if not x:

        return []

    if x[0] == 'list':

        return getlist(x[1]) + [x[2]]

    return [x]

def getfilter(exp, context):

    f = getsymbol(exp)

    if f not in context._filters:

        raise error.ParseError(_("unknown function '%s'") % f)

    return context._filters[f]

def gettemplate(exp, context):

    if exp[0] == 'string':

        return compiletemplate(exp[1], context)

    if exp[0] == 'symbol':

        return context._load(exp[1])

    raise error.ParseError(_("expected template specifier"))

def runstring(context, mapping, data):

    return data

def runsymbol(context, mapping, key):

    v = mapping.get(key)

    if v is None:

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

    if util.safehasattr(v, '__call__'):

        return v(**mapping)

    return v

def buildfilter(exp, context):

    func, data = compileexp(exp[1], context)

    filt = getfilter(exp[2], context)

    return (runfilter, (func, data, filt))

def runfilter(context, mapping, data):

    func, data, filt = data

    try:

        return filt(func(context, mapping, data))

    except (ValueError, AttributeError, TypeError):

        if isinstance(data, tuple):

            dt = data[1]

        else:

            dt = data

        raise util.Abort(_("template filter '%s' is not compatible with "

                           "keyword '%s'") % (filt.func_name, dt))

def buildmap(exp, context):

    func, data = compileexp(exp[1], context)

    ctmpl = gettemplate(exp[2], context)

    return (runmap, (func, data, ctmpl))

def runtemplate(context, mapping, template):

    for func, data in template:

        yield func(context, mapping, data)

def runmap(context, mapping, data):

    func, data, ctmpl = data

    d = func(context, mapping, data)

    if util.safehasattr(d, '__call__'):

        d = d()

    lm = mapping.copy()

    for i in d:

        if isinstance(i, dict):

            lm.update(i)

            yield runtemplate(context, lm, ctmpl)

        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 buildfunc(exp, context):

    n = getsymbol(exp[1])

    args = [compileexp(x, context) for x in getlist(exp[2])]

    if n in funcs:

        f = funcs[n]

        return (f, args)

    if n in context._filters:

        if len(args) != 1:

            raise error.ParseError(_("filter %s expects one argument") % n)

        f = context._filters[n]

        return (runfilter, (args[0][0], args[0][1], f))

def join(context, mapping, args):

    if not (1 <= len(args) <= 2):

        raise error.ParseError(_("join expects one or two arguments"))

    joinset = args[0][0](context, mapping, args[0][1])

    if util.safehasattr(joinset, '__call__'):

        joinset = [x.values()[0] for x in joinset()]

    joiner = " "

    if len(args) > 1:

        joiner = args[1][0](context, mapping, args[1][1])

    first = True

    for x in joinset:

        if first:

            first = False

        else:

            yield joiner

        yield x

methods = {

    "string": lambda e, c: (runstring, e[1]),

    "symbol": lambda e, c: (runsymbol, e[1]),

    "group": lambda e, c: compileexp(e[1], c),

#    ".": buildmember,

    "|": buildfilter,

    "%": buildmap,

    "func": buildfunc,

    }

funcs = {

    "join": join,

}

# template engine

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 util.safehasattr(thing, '__iter__'):

        if thing is not None:

            yield str(thing)

    else:

        for i in thing:

            if isinstance(i, str):

                yield i

            elif not util.safehasattr(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 _load(self, t):

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

        if t not in self._cache:

            self._cache[t] = compiletemplate(self._loader(t), self)

        return self._cache[t]

    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(func(self, mapping, data) for func, data in

                         self._load(t))

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

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.ecache = {}

        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 not val:

                raise SyntaxError(_('%s: missing value') % conf.source('', key))

            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])