#  Copyright (c) 2007, Enthought, Inc.
#  License: BSD Style.

# --(Extended Property depends_on References)-----------------------------------
"""
Extended Property *depends_on* References
=========================================

In Traits 3.0, the **Property** *depends_on* metadata has been extended to
take advantage of the new extended trait name support offered by the
*on_trait_change* method.

Previously, the *depends_on* metadata for a *Property* was restricted to
referencing traits defined either on the same object as the **Property**, or
on an object immediately reachable from the object. For example::

    class Wheel(Part):

        axel     = Instance(Axel)
        position = Property(depends_on = 'axel.position')

        ...

Starting with Traits 3.0, the *depends_on* metadata may now include any
extended trait reference that is allowed by the enhanced *on_trait_change*
method. So, for example it is now legal to write things like::

    class Wheel(Part):

        axel     = Instance(Axel)
        position = Property(depends_on = 'axel.chassis.position')

or::

    class Child(Person):

        mother = Instance(Person)
        father = Instance(Person)
        mood   = Property(depends_on = ['mother.+mood_affecting',
                                        'father.+mood_affecting'])

In particular, in the last example we are declaring that the **Child** class's
*mood* property depends upon the values of any of either its mother or
father object's traits that have *mood_affecting* metadata defined.

Thus, a **Child** object's *mood* property will fire a trait change
notification whenever any of the its mother's or father's mood affecting
traits change.

Refer also to the code tabs for this lesson for a complete example using a
**Property** definition using *depends_on* metadata containing an extended
trait reference. In particular, take a look at the **LeagueModelView Class**
tab's *total_hits* trait definition.
"""

from __future__ import print_function

# FIXME redo example without traitsui

import six.moves as sm

from traits.api import *

from traitsui.api import *

from traitsui.table_column import *


# --[Player Class]--------------------------------------------------------------
# Define a baseball player:
class Player(HasTraits):

    # The name of the player:
    name = Str("<new player>")

    # The number of hits the player made this season:
    hits = Int


# --[Team Class]----------------------------------------------------------------
# Define a baseball team:
class Team(HasTraits):

    # The name of the team:
    name = Str("<new team>")

    # The players on the team:
    players = List(Player)

    # The number of players on the team:
    num_players = Property(depends_on="players")

    def _get_num_players(self):
        """ Implementation of the 'num_players' property.
        """
        return len(self.players)


# --[League Class]--------------------------------------------------------------
# Define a baseball league model:
class League(HasTraits):

    # The name of the league:
    name = Str("<new league>")

    # The teams in the league:
    teams = List(Team)


# --[LeagueModelView Class]-----------------------------------------------------
# Define a ModelView for a League model:
class LeagueModelView(ModelView):

    # The currently selected team:
    team = Instance(Team)

    # The currently selected player:
    player = Instance(Player)

    # Button to add a hit to the current player:
    got_hit = Button("Got a Hit")

    # The total number of hits (note the 'depends_on' extended trait
    # reference):
    total_hits = Property(depends_on="model.teams.players.hits")

    @cached_property
    def _get_total_hits(self):
        """ Returns the total number of hits across all teams and players.
        """
        return sm.reduce(
            add,
            [
                sm.reduce(add, [p.hits for p in t.players], 0)
                for t in self.model.teams
            ],
            0,
        )

    view = View(
        VGroup(
            HGroup(
                Item("total_hits", style="readonly"),
                label="League Statistics",
                show_border=True,
            ),
            VGroup(
                Item(
                    "model.teams",
                    show_label=False,
                    editor=TableEditor(
                        columns=[
                            ObjectColumn(name="name", width=0.70),
                            ObjectColumn(
                                name="num_players",
                                label="# Players",
                                editable=False,
                                width=0.29,
                            ),
                        ],
                        selected="object.team",
                        auto_add=True,
                        row_factory=Team,
                        configurable=False,
                        sortable=False,
                    ),
                ),
                label="League Teams",
                show_border=True,
            ),
            VGroup(
                Item(
                    "object.team.players",
                    show_label=False,
                    editor=TableEditor(
                        columns=[
                            ObjectColumn(name="name", width=0.70),
                            ObjectColumn(
                                name="hits", editable=False, width=0.29
                            ),
                        ],
                        selected="object.player",
                        auto_add=True,
                        row_factory=Player,
                        configurable=False,
                        sortable=False,
                    ),
                ),
                "_",
                HGroup(
                    Item(
                        "got_hit",
                        show_label=False,
                        enabled_when="player is not None",
                    )
                ),
                label="Team Players",
                show_labels=False,
                show_border=True,
            ),
        ),
        resizable=True,
    )

    def _model_changed(self, model):
        """ Handles the 'league' model being initialized.
        """
        if len(model.teams) > 0:
            self.team = model.teams[0]

    def _got_hit_changed(self):
        """ Handles the currently selected player making a hit.
        """
        self.player.hits += 1

    def _team_changed(self, team):
        """ Handles a new team being selected.
        """
        if len(team.players) > 0:
            self.player = team.players[0]
        else:
            self.player = None


# Function to add two numbers (used with 'reduce'):
add = lambda a, b: a + b

# --[Example*]------------------------------------------------------------------

# Define some sample teams and players:
blue_birds = Team(
    name="Blue Birds",
    players=[
        Player(name="Mike Scott", hits=25),
        Player(name="Willy Shofield", hits=37),
        Player(name="Tony Barucci", hits=19),
    ],
)

chicken_hawks = Team(
    name="Chicken Hawks",
    players=[
        Player(name="Jimmy Domore", hits=34),
        Player(name="Bill Janks", hits=16),
        Player(name="Tim Saunders", hits=27),
    ],
)

eagles = Team(
    name="Eagles",
    players=[
        Player(name="Joe Peppers", hits=33),
        Player(name="Sam Alone", hits=12),
        Player(name="Roger Clemson", hits=23),
    ],
)

# Create a league and its corresponding model view:
demo = LeagueModelView(
    League(
        name="National Baseball Conference",
        teams=[blue_birds, chicken_hawks, eagles],
    )
)