# Copyright 2004-2017 Tom Rothamel <pytom@bishoujo.us>
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

# This code implements the ability to "warp" to a given location in
# the Ren'Py source code, given the filename and line number of the
# location.

import renpy

warp_spec = None


def warp():
    """
    Given a filename and line number, this attempts to warp the user
    to that filename and line number.
    """

    global warp_spec

    spec = warp_spec
    warp_spec = None

    if spec is None:
        return None

    if ':' not in spec:
        raise Exception('No : found in warp location.')

    filename, line = spec.split(':', 1)
    line = int(line)

    if not renpy.config.developer:
        raise Exception("Can't warp, developer mode disabled.")

    # First, compute for each statement reachable from a scene statement,
    # one statement that reaches that statement.

    prev = { }

    workset = { n for n in renpy.game.script.namemap.itervalues() if isinstance(n, renpy.ast.Scene) }
    seenset = set(workset)

    # This is called to indicate that next can be executed following node.
    def add(node, next):  # @ReservedAssignment
        if next not in seenset:
            seenset.add(next)
            workset.add(next)
            prev[next] = node

    while workset:

        n = workset.pop()

        if isinstance(n, renpy.ast.Menu):
            for i in n.items:
                if i[2] is not None:
                    add(n, i[2][0])

        if isinstance(n, renpy.ast.Jump):
            if not n.expression and n.target in renpy.game.script.namemap:
                add(n, renpy.game.script.namemap[n.target])
                continue

        if isinstance(n, renpy.ast.While):
            add(n, n.block[0])

        if isinstance(n, renpy.ast.If):

            seen_true = False

            for condition, block in n.entries:
                add(n, block[0])

                if condition == "True":
                    seen_true = True

            if seen_true:
                continue

        if isinstance(n, renpy.ast.UserStatement):
            add(n, n.get_next())

        elif getattr(n, 'next', None) is not None:
            add(n, n.next)

    # Now, attempt to find a statement preceding the line that the
    # user wants to warp to.

    candidates = [ (n.linenumber, n)
                   for n in seenset
                   if n.filename.endswith('/' + filename) and n.linenumber <= line ]

    # We didn't find any candidate statements, so give up the warp.
    if not candidates:
        return

    # Sort the list of candidates, so they're ordered by linenumber.
    candidates.sort()

    # Pick the candidate immediately before (or on) the line.
    node = candidates[-1][1]

    # Now, determine a list of nodes to run while getting to this node.
    run = [ ]
    n = node

    while True:
        n = prev.get(n, None)
        if n:
            run.append(n)
        else:
            break

    run.reverse()

    # Determine which statements we want to execute, and then run
    # only them.

    toexecute = ( renpy.ast.Scene, renpy.ast.Show, renpy.ast.Hide )

    for n in run:
        if isinstance(n, toexecute):
            n.execute()

    # Now, return the name of the place where we will warp to. This
    # becomes the new starting point of the game.

    return node.name
