#!/usr/bin/env python
import os
import sys

sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
from zulip_tools import check_output

class Record:
    pass

def validate(fn):
    text = open(fn).read()

    state = Record()

    def NoStartTag(end_tag):
        raise Exception('No start tag for %s' % end_tag)

    def start_tag_matcher(s):
        start_line = state.line
        start_col = state.col
        state.depth += 1
        tag = s[1:-1]
        start_tag = tag.split()[0]
        old_matcher = state.matcher
        def f(end_tag):
            problem = None
            if start_tag != end_tag[2:-1]:
                problem = 'Mismatched tag.'
            elif state.line > start_line + 1 and state.col != start_col:
                problem = 'Bad indentation.'
            if problem:
                raise Exception('''
                    fn: %s
                    %s
                    start:
                        %s
                        line %d, col %d
                    end tag:
                        %s
                        line %d, col %d
                    ''' % (fn, problem, s, start_line, start_col, end_tag, state.line, state.col))
            state.matcher = old_matcher
            state.depth -= 1
        return f

    state.depth = 0
    state.i = 0
    state.line = 1
    state.col = 1
    state.matcher = NoStartTag

    def advance(n):
        for _ in range(n):
            state.i += 1
            if state.i >= 0 and text[state.i - 1] == '\n':
                state.line += 1
                state.col = 1
            else:
                state.col += 1

    while True:
        if state.i >= len(text):
            break
        c = text[state.i]
        if c == '<':
            end = state.i + 1
            while end < len(text) and text[end] != '>':
                end += 1
            if text[end] != '>':
                raise Exception('Tag missing >')
            s = text[state.i:end+1]
            if s.startswith('</'):
                state.matcher(s)
            else:
                if not s.endswith('/>'):
                    state.matcher = start_tag_matcher(s)
            advance(len(s))
            continue
        advance(1)

    assert state.depth == 0

git_files = map(str.strip, check_output(['git', 'ls-files']).split('\n'))

# Check all our handlebars templates.
templates = [fn for fn in git_files if fn.endswith('.handlebars')]
assert len(templates) >= 10 # sanity check that we are actually doing work

# Django templates are pretty messy now, so we whitelist them for now.
templates += [
    'templates/zerver/settings.html'
]

for fn in templates:
    validate(fn)