"""Replace dialog for IDLE. Inherits SearchDialogBase for GUI.
Uses idlelib.searchengine.SearchEngine for search capability.
Defines various replace related functions like replace, replace all,
and replace+find.
"""
import re

from tkinter import StringVar, TclError

from idlelib.searchbase import SearchDialogBase
from idlelib import searchengine


def replace(text):
 """Create or reuse a singleton ReplaceDialog instance.

 The singleton dialog saves user entries and preferences
 across instances.

 Args:
 text: Text widget containing the text to be searched.
 """
 root = text._root()
 engine = searchengine.get(root)
 if not hasattr(engine, "_replacedialog"):
 engine._replacedialog = ReplaceDialog(root, engine)
 dialog = engine._replacedialog
 dialog.open(text)


class ReplaceDialog(SearchDialogBase):
 "Dialog for finding and replacing a pattern in text."

 title = "Replace Dialog"
 icon = "Replace"

 def __init__(self, root, engine):
 """Create search dialog for finding and replacing text.

 Uses SearchDialogBase as the basis for the GUI and a
 searchengine instance to prepare the search.

 Attributes:
 replvar: StringVar containing 'Replace with:' value.
 replent: Entry widget for replvar. Created in
 create_entries().
 ok: Boolean used in searchengine.search_text to indicate
 whether the search includes the selection.
 """
 super().__init__(root, engine)
 self.replvar = StringVar(root)

 def open(self, text):
 """Make dialog visible on top of others and ready to use.

 Also, highlight the currently selected text and set the
 search to include the current selection (self.ok).

 Args:
 text: Text widget being searched.
 """
 SearchDialogBase.open(self, text)
 try:
 first = text.index("sel.first")
 except TclError:
 first = None
 try:
 last = text.index("sel.last")
 except TclError:
 last = None
 first = first or text.index("insert")
 last = last or first
 self.show_hit(first, last)
 self.ok = True

 def create_entries(self):
 "Create base and additional label and text entry widgets."
 SearchDialogBase.create_entries(self)
 self.replent = self.make_entry("Replace with:", self.replvar)[0]

 def create_command_buttons(self):
 """Create base and additional command buttons.

 The additional buttons are for Find, Replace,
 Replace+Find, and Replace All.
 """
 SearchDialogBase.create_command_buttons(self)
 self.make_button("Find", self.find_it)
 self.make_button("Replace", self.replace_it)
 self.make_button("Replace+Find", self.default_command, isdef=True)
 self.make_button("Replace All", self.replace_all)

 def find_it(self, event=None):
 "Handle the Find button."
 self.do_find(False)

 def replace_it(self, event=None):
 """Handle the Replace button.

 If the find is successful, then perform replace.
 """
 if self.do_find(self.ok):
 self.do_replace()

 def default_command(self, event=None):
 """Handle the Replace+Find button as the default command.

 First performs a replace and then, if the replace was
 successful, a find next.
 """
 if self.do_find(self.ok):
 if self.do_replace(): # Only find next match if replace succeeded.
 # A bad re can cause it to fail.
 self.do_find(False)

 def _replace_expand(self, m, repl):
 "Expand replacement text if regular expression."
 if self.engine.isre():
 try:
 new = m.expand(repl)
 except re.error:
 self.engine.report_error(repl, 'Invalid Replace Expression')
 new = None
 else:
 new = repl

 return new

 def replace_all(self, event=None):
 """Handle the Replace All button.

 Search text for occurrences of the Find value and replace
 each of them. The 'wrap around' value controls the start
 point for searching. If wrap isn't set, then the searching
 starts at the first occurrence after the current selection;
 if wrap is set, the replacement starts at the first line.
 The replacement is always done top-to-bottom in the text.
 """
 prog = self.engine.getprog()
 if not prog:
 return
 repl = self.replvar.get()
 text = self.text
 res = self.engine.search_text(text, prog)
 if not res:
 self.bell()
 return
 text.tag_remove("sel", "1.0", "end")
 text.tag_remove("hit", "1.0", "end")
 line = res[0]
 col = res[1].start()
 if self.engine.iswrap():
 line = 1
 col = 0
 ok = True
 first = last = None
 # XXX ought to replace circular instead of top-to-bottom when wrapping
 text.undo_block_start()
 while True:
 res = self.engine.search_forward(text, prog, line, col,
 wrap=False, ok=ok)
 if not res:
 break
 line, m = res
 chars = text.get("%d.0" % line, "%d.0" % (line+1))
 orig = m.group()
 new = self._replace_expand(m, repl)
 if new is None:
 break
 i, j = m.span()
 first = "%d.%d" % (line, i)
 last = "%d.%d" % (line, j)
 if new == orig:
 text.mark_set("insert", last)
 else:
 text.mark_set("insert", first)
 if first != last:
 text.delete(first, last)
 if new:
 text.insert(first, new)
 col = i + len(new)
 ok = False
 text.undo_block_stop()
 if first and last:
 self.show_hit(first, last)
 self.close()

 def do_find(self, ok=False):
 """Search for and highlight next occurrence of pattern in text.

 No text replacement is done with this option.
 """
 if not self.engine.getprog():
 return False
 text = self.text
 res = self.engine.search_text(text, None, ok)
 if not res:
 self.bell()
 return False
 line, m = res
 i, j = m.span()
 first = "%d.%d" % (line, i)
 last = "%d.%d" % (line, j)
 self.show_hit(first, last)
 self.ok = True
 return True

 def do_replace(self):
 "Replace search pattern in text with replacement value."
 prog = self.engine.getprog()
 if not prog:
 return False
 text = self.text
 try:
 first = pos = text.index("sel.first")
 last = text.index("sel.last")
 except TclError:
 pos = None
 if not pos:
 first = last = pos = text.index("insert")
 line, col = searchengine.get_line_col(pos)
 chars = text.get("%d.0" % line, "%d.0" % (line+1))
 m = prog.match(chars, col)
 if not prog:
 return False
 new = self._replace_expand(m, self.replvar.get())
 if new is None:
 return False
 text.mark_set("insert", first)
 text.undo_block_start()
 if m.group():
 text.delete(first, last)
 if new:
 text.insert(first, new)
 text.undo_block_stop()
 self.show_hit(first, text.index("insert"))
 self.ok = False
 return True

 def show_hit(self, first, last):
 """Highlight text between first and last indices.

 Text is highlighted via the 'hit' tag and the marked
 section is brought into view.

 The colors from the 'hit' tag aren't currently shown
 when the text is displayed. This is due to the 'sel'
 tag being added first, so the colors in the 'sel'
 config are seen instead of the colors for 'hit'.
 """
 text = self.text
 text.mark_set("insert", first)
 text.tag_remove("sel", "1.0", "end")
 text.tag_add("sel", first, last)
 text.tag_remove("hit", "1.0", "end")
 if first == last:
 text.tag_add("hit", first)
 else:
 text.tag_add("hit", first, last)
 text.see("insert")
 text.update_idletasks()

 def close(self, event=None):
 "Close the dialog and remove hit tags."
 SearchDialogBase.close(self, event)
 self.text.tag_remove("hit", "1.0", "end")


def _replace_dialog(parent): # htest #
 from tkinter import Toplevel, Text, END, SEL
 from tkinter.ttk import Frame, Button

 top = Toplevel(parent)
 top.title("Test ReplaceDialog")
 x, y = map(int, parent.geometry().split('+')[1:])
 top.geometry("+%d+%d" % (x, y + 175))

 # mock undo delegator methods
 def undo_block_start():
 pass

 def undo_block_stop():
 pass

 frame = Frame(top)
 frame.pack()
 text = Text(frame, inactiveselectbackground='gray')
 text.undo_block_start = undo_block_start
 text.undo_block_stop = undo_block_stop
 text.pack()
 text.insert("insert","This is a sample sTring\nPlus MORE.")
 text.focus_set()

 def show_replace():
 text.tag_add(SEL, "1.0", END)
 replace(text)
 text.tag_remove(SEL, "1.0", END)

 button = Button(frame, text="Replace", command=show_replace)
 button.pack()

if __name__ == '__main__':
 from unittest import main
 main('idlelib.idle_test.test_replace', verbosity=2, exit=False)

 from idlelib.idle_test.htest import run
 run(_replace_dialog)