#!/usr/bin/env python
# encoding: utf-8

"""Parsing of snippet files."""

from collections import defaultdict
import glob
import os

from UltiSnips import _vim
from UltiSnips.snippet.definition import UltiSnipsSnippetDefinition
from UltiSnips.snippet.source.file._base import SnippetFileSource
from UltiSnips.snippet.source.file._common import handle_extends, \
    handle_action, handle_context
from UltiSnips.text import LineIterator, head_tail


def find_snippet_files(ft, directory):
    """Returns all matching snippet files for 'ft' in 'directory'."""
    patterns = ['%s.snippets', '%s_*.snippets', os.path.join('%s', '*')]
    ret = set()
    directory = os.path.expanduser(directory)
    for pattern in patterns:
        for fn in glob.glob(os.path.join(directory, pattern % ft)):
            ret.add(os.path.realpath(fn))
    return ret


def find_all_snippet_files(ft):
    """Returns all snippet files matching 'ft' in the given runtime path
    directory."""
    if _vim.eval("exists('b:UltiSnipsSnippetDirectories')") == '1':
        snippet_dirs = _vim.eval('b:UltiSnipsSnippetDirectories')
    else:
        snippet_dirs = _vim.eval('g:UltiSnipsSnippetDirectories')
    if len(snippet_dirs) == 1 and os.path.isabs(snippet_dirs[0]):
        check_dirs = ['']
    else:
        check_dirs = _vim.eval('&runtimepath').split(',')
    patterns = ['%s.snippets', '%s_*.snippets', os.path.join('%s', '*')]
    ret = set()
    for rtp in check_dirs:
        for snippet_dir in snippet_dirs:
            if snippet_dir == 'snippets':
                raise RuntimeError(
                    "You have 'snippets' in UltiSnipsSnippetDirectories. This "
                    'directory is reserved for snipMate snippets. Use another '
                    'directory for UltiSnips snippets.')
            pth = os.path.realpath(os.path.expanduser(
                os.path.join(rtp, snippet_dir)))
            for pattern in patterns:
                for fn in glob.glob(os.path.join(pth, pattern % ft)):
                    ret.add(fn)
    return ret


def _handle_snippet_or_global(
    filename, line, lines, python_globals, priority, pre_expand, context
):
    """Parses the snippet that begins at the current line."""
    start_line_index = lines.line_index
    descr = ''
    opts = ''

    # Ensure this is a snippet
    snip = line.split()[0]

    # Get and strip options if they exist
    remain = line[len(snip):].strip()
    words = remain.split()

    if len(words) > 2:
        # second to last word ends with a quote
        if '"' not in words[-1] and words[-2][-1] == '"':
            opts = words[-1]
            remain = remain[:-len(opts) - 1].rstrip()

    if 'e' in opts and not context:
        left = remain[:-1].rfind('"')
        if left != -1 and left != 0:
            context, remain = remain[left:].strip('"'), remain[:left]

    # Get and strip description if it exists
    remain = remain.strip()
    if len(remain.split()) > 1 and remain[-1] == '"':
        left = remain[:-1].rfind('"')
        if left != -1 and left != 0:
            descr, remain = remain[left:], remain[:left]

    # The rest is the trigger
    trig = remain.strip()
    if len(trig.split()) > 1 or 'r' in opts:
        if trig[0] != trig[-1]:
            return 'error', ("Invalid multiword trigger: '%s'" % trig,
                             lines.line_index)
        trig = trig[1:-1]
    end = 'end' + snip
    content = ''

    found_end = False
    for line in lines:
        if line.rstrip() == end:
            content = content[:-1]  # Chomp the last newline
            found_end = True
            break
        content += line

    if not found_end:
        return 'error', ("Missing 'endsnippet' for %r" %
                         trig, lines.line_index)

    if snip == 'global':
        python_globals[trig].append(content)
    elif snip == 'snippet':
        definition = UltiSnipsSnippetDefinition(
            priority, trig, content,
            descr, opts, python_globals,
            '%s:%i' % (filename, start_line_index),
            context, pre_expand)
        return 'snippet', (definition,)
    else:
        return 'error', ("Invalid snippet type: '%s'" % snip, lines.line_index)


def _parse_snippets_file(data, filename):
    """Parse 'data' assuming it is a snippet file.

    Yields events in the file.

    """

    python_globals = defaultdict(list)
    lines = LineIterator(data)
    current_priority = 0
    actions = {}
    context = None
    for line in lines:
        if not line.strip():
            continue

        head, tail = head_tail(line)
        if head in ('snippet', 'global'):
            snippet = _handle_snippet_or_global(
                filename, line, lines,
                python_globals,
                current_priority,
                actions,
                context
            )

            actions = {}
            context = None
            if snippet is not None:
                yield snippet
        elif head == 'extends':
            yield handle_extends(tail, lines.line_index)
        elif head == 'clearsnippets':
            yield 'clearsnippets', (current_priority, tail.split())
        elif head == 'context':
            head, context, = handle_context(tail, lines.line_index)
            if head == 'error':
                yield (head, tail)
        elif head == 'priority':
            try:
                current_priority = int(tail.split()[0])
            except (ValueError, IndexError):
                yield 'error', ('Invalid priority %r' % tail, lines.line_index)
        elif head in ['pre_expand', 'post_expand', 'post_jump']:
            head, tail = handle_action(head, tail, lines.line_index)
            if head == 'error':
                yield (head, tail)
            else:
                actions[head], = tail
        elif head and not head.startswith('#'):
            yield 'error', ('Invalid line %r' % line.rstrip(), lines.line_index)


class UltiSnipsFileSource(SnippetFileSource):

    """Manages all snippets definitions found in rtp for ultisnips."""

    def _get_all_snippet_files_for(self, ft):
        return find_all_snippet_files(ft)

    def _parse_snippet_file(self, filedata, filename):
        for event, data in _parse_snippets_file(filedata, filename):
            yield event, data