#!/usr/bin/env python3

from starlette.applications import Starlette
from starlette.responses import HTMLResponse
from starlette.routing import Route
import pygments
from pygments.formatters import HtmlFormatter
from pygments.lexers import guess_lexer, guess_lexer_for_filename
from pygments.lexers.special import TextLexer
from pygments.util import ClassNotFound

formatter = None

async def startup_task():
    guess_lexer('')
    global formatter
    formatter = HtmlFormatter(style='pastie', nobackground=True)

def do_highlight(filename, data):
    try:
        lexer = guess_lexer_for_filename(filename, data)
    except ClassNotFound:
        try:
            lexer = guess_lexer(data)
            # SqlLexer always gives 0.01
            if lexer.analyse_text(data) <= 0.01:
                lexer = TextLexer()
        except ClassNotFound:
            lexer = TextLexer()
    return ''.join([
        f'<!-- Pygments {pygments.__version__}: {lexer.name} ({lexer.__class__.__name__}) -->',
        '<style>', formatter.get_style_defs('.highlight'), '</style>',
        pygments.highlight(data, lexer, formatter)
    ])

async def run_highlight(request):
    return HTMLResponse(do_highlight(request.query_params['filename'], await request.body()))

app = Starlette(
        routes=[
            Route('/highlight', run_highlight, methods=["POST"]),
            ],
        on_startup=[startup_task],
        )