#!/usr/bin/env nix-script
#!>python3

## Regex tester

import tkinter
import tkinter.messagebox
import traceback


class Text(tkinter.Text):
	"""
	Tkinter Text Widget
	Override that allows to highlight words with regex.
	"""
	def __init__(self, *args, **kwargs):
		tkinter.Text.__init__(self, *args, **kwargs)

	def highlight(self, pattern, tag, start="1.0", stop="end", regex=True):
		"""
		Highlight text matched by "pattern" and apply it the tag "tag"
		Specify "start" and "stop" in order to restrict the search and
		regex=False if pattern is not a regex.
		"""
		start = self.index(start)
		stop = self.index(stop)
		self.mark_set("matchStart", start)
		self.mark_set("matchEnd", start)
		self.mark_set("searchLimit", stop)
		occurrences = tkinter.IntVar()
		while True:
			index = self.search(
				pattern,
				"matchEnd",
				"searchLimit",
				count=occurrences,
				regexp=regex
			)
			if index == "":
				break
			self.mark_set("matchStart", index)
			self.mark_set("matchEnd", "%s+%sc" % (index, occurrences.get()))
			self.tag_add(tag, "matchStart", "matchEnd")


class Application(tkinter.Frame):
	"""
	Application
	Initialize it with a window created by Tk().
	"""
	def __init__(self, window):
		tkinter.Frame.__init__(self, window)

		self.options = {
			"font": ("Monaco", 13),
			"borderwidth": 2,
			"highlightthickness": 0,
			"relief": "sunken",
			"insertbackground": "#fff"
		}
		self.last = ""

		#Window settings
		window.columnconfigure(1, weight=1)
		window.rowconfigure(0, weight=1)
		window.geometry("800x500+540+300")
		window.title("reQuery")

		#Inizialize
		self.grid()
		self.widgets()

		#Main loop
		self.loop()

	def widgets(self):
		"""Create and draw the widgets of the window."""
		self.search = Text(
			window, width=100, height=30, **self.options)
		self.expression = tkinter.Entry(window, **self.options)

		#Layout
		self.search.grid(
			column=1, row=0, sticky="nswe", pady=(6, 3), padx=6)
		self.expression.grid(
			column=1, row=1, sticky="nswe", pady=(3, 6), padx=6)

	def test(self):
		"""
		Highlight in the text output generated by the search
		If this is not valid is colored in red.
		If it is valid is colored in green as well as the text
		to which it corresponds.
		"""

		expression = self.expression.get()
		if expression == "" or expression == self.last:
			return
		try:
			self.search.tag_configure("result", foreground="#648f00")
			self.search.highlight(expression, "result")
		except tkinter.TclError:
			self.expression.config(fg="#92182b")
			tkinter.messagebox.showerror(
				"reQuery", "Syntax error",
				detail=traceback.format_exc(0).split(":")[3])
			self.display_error = False
		else:
			self.expression.config(fg="#648f00")
		self.last = expression

	def loop(self):
		"""
		Main loop
		Executed every 200 ms.
		Updates regex search.
		"""
		self.test()
		self.after(200, self.loop)

window = tkinter.Tk()
app = Application(window)
app.mainloop()