#!/usr/bin/env python

#****************************************************************************
# treestates.py, class to keep track of recent files' meta-data
#
# Copyright (C) 2004, Jan Hustak
#
# This is free software; you can redistribute it and/or modify it under the
# terms of the GNU General Public License, Version 2.  This program is
# distributed in the hope that it will be useful, but WITTHOUT ANY WARRANTY.
#*****************************************************************************

import globalref
from os import stat
from qt import QPoint
from time import time

class TreeStates:
    """Tracks, loads & saves tree states of recently opened files"""
    DefaultState = '0:0:0:0' # timestamp:firstVisible:selected:openNodes
    def __init__(self, fileList):
        self.treeStates = {}
        for i in range(len(fileList)):
            state = globalref.options.strData(self.optionName(i), True)
            if not state:
                state = TreeStates.DefaultState
            self.treeStates[fileList[i]] = state
        self.currentFile = ''

    def fileListChanged(self, newList):
        """Sync tree states with the list of recent files"""
        newTreeStates = {}
        self.currentFile = ''
        for i in range(len(newList)):
            filePath = newList[i]
            treeState = self.getStateByFile(filePath)
            globalref.options.changeData(self.optionName(i), treeState, True)
            newTreeStates[filePath] = treeState
        globalref.options.writeChanges()
        self.treeStates = newTreeStates
        if newList:
            self.currentFile = newList[0]

    def clear(self):
        """Clear tree states of all recent files"""
        for i in range(len(self.treeStates)):
            globalref.options.changeData(self.optionName(i), \
                                         TreeStates.DefaultState, True)
        globalref.options.writeChanges()
        self.treeStates = {}

    def loadCurrent(self, view):
        """Apply the tree state to the currently open file
           and update the views"""
        if not self.currentFile:
            globalref.updateViewAll()
            return
        fileTimestamp = stat(self.currentFile).st_mtime
        stateTokens = self.getStateByFile(self.currentFile).split(':')
        if fileTimestamp > int(stateTokens[0]): # file modified externally
            interimState = str(int(fileTimestamp)) + ':0:0:0' # see DefaultState
            self.treeStates[self.currentFile] = interimState
            globalref.options.changeData(self.optionName(0), interimState, True)
            stateTokens = interimState.split(':')
            globalref.options.writeChanges()
        allNodes = globalref.docRef.root.descendantList(True)
        try:
            selectedNode = allNodes[int(stateTokens[2])]
        except IndexError:
            selectedNode = allNodes[0]
        globalref.docRef.selection.replace([selectedNode])
        self.loadOpenNodes(allNodes, stateTokens[3])
        globalref.updateViewAll()
        try:
            firstVisibleItem = allNodes[int(stateTokens[1])]
            view.setContentsPos(0, view.itemPos(firstVisibleItem.viewData))
        except (IndexError, AttributeError):
            pass

    def saveCurrent(self, view):
        """Persist the tree state of the currently open file"""
        if not self.currentFile:
            return
        allNodes = globalref.docRef.root.descendantList(True)
        firstNode = str(allNodes.index(view.itemAt(QPoint(0, 0)).docItemRef))
        selectNode = str(allNodes.index(globalref.docRef.selection.currentItem))
        openNodes = self.saveOpenNodes(allNodes)
        state = '%s:%s:%s:%s' % (str(int(time())), firstNode, selectNode, \
                                 openNodes)
        self.treeStates[self.currentFile] = state
        globalref.options.changeData(self.optionName(0), state, True)
        globalref.options.writeChanges()

    def getStateByFile(self, filePath):
        """Retrieve the given file's tree state or the default"""
        try:
            treeState = self.treeStates[filePath]
        except KeyError:
            treeState = TreeStates.DefaultState
        if not treeState:
            treeState = TreeStates.DefaultState
        return treeState

    def optionName(self, index):
        return 'TreeState' + `index + 1`

    def loadOpenNodes(self, allNodes, stateStr):
        """Set nodes' visibility state according to stateStr"""
        openNodeIndices = [int(x) for x in stateStr.split(',')]
        for index in openNodeIndices:
            try:
                node = allNodes[index]
            except IndexError:
                return  # nodes don't exist, posssibly due to file import issues
            while not node.open and node != allNodes[0]:
                node.open = True
                node = node.parent
    
    def saveOpenNodes(self, allNodes):
        """Serialize visible nodes into a string"""
        openList = []
        if not allNodes[0].open: # root closed, return default
            return '0'
        for i, node in enumerate(allNodes):
            if node.open and \
                    not [child for child in node.childList if child.open] and \
                    node.allAncestorsOpen():
                openList.append(str(i))
        return ','.join(openList)