# Copyright 2014 OpenStack Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import datetime
import logging

import urwid

from gertty import gitrepo
from gertty import keymap
from gertty import mywid
from gertty import gitrepo
from gertty import sync
from gertty.view import mouse_scroll_decorator

class PatchsetDialog(urwid.WidgetWrap, mywid.LineBoxTitlePropertyMixin):
    signals = ['ok', 'cancel']

    def __init__(self, patchsets, old, new):
        button_widgets = []
        ok_button = mywid.FixedButton('OK')
        cancel_button = mywid.FixedButton('Cancel')
        urwid.connect_signal(ok_button, 'click',
                             lambda button:self._emit('ok'))
        urwid.connect_signal(cancel_button, 'click',
                             lambda button:self._emit('cancel'))
        button_widgets.append(('pack', ok_button))
        button_widgets.append(('pack', cancel_button))
        button_columns = urwid.Columns(button_widgets, dividechars=2)

        left = []
        right = []
        left.append(urwid.Text('Old'))
        right.append(urwid.Text('New'))
        self.old_buttons = []
        self.new_buttons = []
        self.patchset_keys = {}
        oldb = mywid.FixedRadioButton(self.old_buttons, 'Base',
                                      state=(old==None))
        left.append(oldb)
        right.append(urwid.Text(''))
        self.patchset_keys[oldb] = None
        for key, num in patchsets:
            oldb = mywid.FixedRadioButton(self.old_buttons, 'Patchset %d' % num,
                                          state=(old==key))
            newb = mywid.FixedRadioButton(self.new_buttons, 'Patchset %d' % num,
                                          state=(new==key))
            left.append(oldb)
            right.append(newb)
            self.patchset_keys[oldb] = key
            self.patchset_keys[newb] = key
        left = urwid.Pile(left)
        right = urwid.Pile(right)
        table  = urwid.Columns([left, right])
        rows = []
        rows.append(table)
        rows.append(urwid.Divider())
        rows.append(button_columns)
        pile = urwid.Pile(rows)
        fill = urwid.Filler(pile, valign='top')
        title = 'Patchsets'
        super(PatchsetDialog, self).__init__(urwid.LineBox(fill, title))

    def getSelected(self):
        old = new = None
        for b in self.old_buttons:
            if b.state:
                old = self.patchset_keys[b]
                break
        for b in self.new_buttons:
            if b.state:
                new = self.patchset_keys[b]
                break
        return old, new

class LineContext(object):
    def __init__(self, old_file_key, new_file_key,
                 old_fn, new_fn, old_ln, new_ln,
                 header=False):
        self.old_file_key = old_file_key
        self.new_file_key = new_file_key
        self.old_fn = old_fn
        self.new_fn = new_fn
        self.old_ln = old_ln
        self.new_ln = new_ln
        self.header = header

class BaseDiffCommentEdit(urwid.Columns):
    pass

class BaseDiffComment(urwid.Columns):
    pass

class BaseDiffLine(urwid.Button):
    def selectable(self):
        return True

    def search(self, search, attribute):
        pass

class BaseFileHeader(urwid.Button):
    def selectable(self):
        return True

    def search(self, search, attribute):
        pass

class BaseFileReminder(urwid.WidgetWrap):
    pass

class DiffContextButton(urwid.WidgetWrap):
    def selectable(self):
        return True

    def __init__(self, view, diff, chunk):
        focus_map={'context-button':'focused-context-button'}
        buttons = [mywid.FixedButton(('context-button', "Expand previous 10"),
                                     on_press=self.prev),
                   mywid.FixedButton(('context-button', "Expand"),
                                     on_press=self.all),
                   mywid.FixedButton(('context-button', "Expand next 10"),
                                     on_press=self.next)]
        self._buttons = buttons
        buttons = [('pack', urwid.AttrMap(b, None, focus_map=focus_map)) for b in buttons]
        buttons = urwid.Columns([urwid.Text('')] + buttons + [urwid.Text('')],
                                dividechars=4)
        buttons = urwid.AttrMap(buttons, 'context-button')
        super(DiffContextButton, self).__init__(buttons)
        self.view = view
        self.diff = diff
        self.chunk = chunk
        self.update()

    def update(self):
        self._buttons[1].set_label("Expand %s lines of context" %
                                   (len(self.chunk.lines)),)

    def prev(self, button):
        self.view.expandChunk(self.diff, self.chunk, from_start=10)

    def all(self, button):
        self.view.expandChunk(self.diff, self.chunk, expand_all=True)

    def next(self, button):
        self.view.expandChunk(self.diff, self.chunk, from_end=-10)

@mouse_scroll_decorator.ScrollByWheel
class BaseDiffView(urwid.WidgetWrap, mywid.Searchable):
    def getCommands(self):
        return [
            (keymap.ACTIVATE,
             "Add an inline comment"),
            (keymap.SELECT_PATCHSETS,
             "Select old/new patchsets to diff"),
            (keymap.INTERACTIVE_SEARCH,
             "Interactive search"),
            ]

    def help(self):
        key = self.app.config.keymap.formatKeys
        commands = self.getCommands()
        return [(c[0], key(c[0]), c[1]) for c in commands]

    def __init__(self, app, new_revision_key):
        super(BaseDiffView, self).__init__(urwid.Pile([]))
        self.log = logging.getLogger('gertty.view.diff')
        self.app = app
        self.old_revision_key = None  # Base
        self.new_revision_key = new_revision_key
        self._init()

    def _init(self):
        del self._w.contents[:]
        self.searchInit()
        with self.app.db.getSession() as session:
            new_revision = session.getRevision(self.new_revision_key)
            old_comments = []
            new_comments = []
            self.old_file_keys = {}
            self.new_file_keys = {}
            if self.old_revision_key is not None:
                old_revision = session.getRevision(self.old_revision_key)
                self.old_revision_num = old_revision.number
                old_str = 'patchset %s' % self.old_revision_num
                self.base_commit = old_revision.commit
                for f in old_revision.files:
                    old_comments += f.comments
                    self.old_file_keys[f.path] = f.key
                show_old_commit = True
            else:
                old_revision = None
                self.old_revision_num = None
                old_str = 'base'
                self.base_commit = new_revision.parent
                show_old_commit = False
                # The old files are the same as the new files since we
                # are diffing from base -> change, however, we should
                # use the old file names for file lookup.
                for f in new_revision.files:
                    if f.old_path:
                        self.old_file_keys[f.old_path] = f.key
                    else:
                        self.old_file_keys[f.path] = f.key
            self.title = u'Diff of %s change %s from %s to patchset %s' % (
                new_revision.change.project.name,
                new_revision.change.number,
                old_str, new_revision.number)
            self.short_title = u'Diff of %s' % (new_revision.change.number,)
            self.new_revision_num = new_revision.number
            self.change_key = new_revision.change.key
            self.project_name = new_revision.change.project.name
            self.commit = new_revision.commit
            for f in new_revision.files:
                new_comments += f.comments
                self.new_file_keys[f.path] = f.key
            comment_lists = {}
            comment_filenames = set()
            for comment in new_comments:
                path = comment.file.path
                if comment.parent:
                    if old_revision:  # we're not looking at the base
                        continue
                    key = 'old'
                    if comment.file.old_path:
                        path = comment.file.old_path
                else:
                    key = 'new'
                if comment.draft:
                    key += 'draft'
                key += '-' + str(comment.line)
                key += '-' + path
                comment_list = comment_lists.get(key, [])
                if comment.draft:
                    message = comment.message
                else:
                    message = [('comment-name', comment.author.name),
                               ('comment', u': '+comment.message)]
                comment_list.append((comment.key, message))
                comment_lists[key] = comment_list
                comment_filenames.add(path)
            for comment in old_comments:
                if comment.parent:
                    continue
                path = comment.file.path
                key = 'old'
                if comment.draft:
                    key += 'draft'
                key += '-' + str(comment.line)
                key += '-' + path
                comment_list = comment_lists.get(key, [])
                if comment.draft:
                    message = comment.message
                else:
                    message = [('comment-name', comment.author.name),
                               ('comment', u': '+comment.message)]
                comment_list.append((comment.key, message))
                comment_lists[key] = comment_list
                comment_filenames.add(path)
        repo = gitrepo.get_repo(self.project_name, self.app.config)
        self._w.contents.append((self.app.header, ('pack', 1)))
        self.file_reminder = self.makeFileReminder()
        self._w.contents.append((self.file_reminder, ('pack', 1)))
        lines = []  # The initial set of lines to display
        self.file_diffs = [{}, {}]  # Mapping of fn -> DiffFile object (old, new)
        # this is a list of files:
        diffs = repo.diff(self.base_commit, self.commit,
                          show_old_commit=show_old_commit)
        for diff in diffs:
            comment_filenames.discard(diff.oldname)
            comment_filenames.discard(diff.newname)
        # There are comments referring to these files which do not
        # appear in the diff so we should create fake diff objects
        # that contain the full text.
        for filename in comment_filenames:
            diff = repo.getFile(self.base_commit, self.commit, filename)
            if diff:
                diffs.append(diff)
            else:
                self.log.debug("Unable to find file %s in commit %s" % (filename, self.commit))
        for i, diff in enumerate(diffs):
            if i > 0:
                lines.append(urwid.Text(''))
            self.file_diffs[gitrepo.OLD][diff.oldname] = diff
            self.file_diffs[gitrepo.NEW][diff.newname] = diff
            lines.extend(self.makeFileHeader(diff, comment_lists))
            for chunk in diff.chunks:
                if chunk.context:
                    if not chunk.first:
                        lines += self.makeLines(diff, chunk.lines[:10], comment_lists)
                        del chunk.lines[:10]
                    button = DiffContextButton(self, diff, chunk)
                    chunk.button = button
                    lines.append(button)
                    if not chunk.last:
                        lines += self.makeLines(diff, chunk.lines[-10:], comment_lists)
                        del chunk.lines[-10:]
                    chunk.calcRange()
                    chunk.button.update()
                    if not chunk.lines:
                        lines.remove(button)
                else:
                    lines += self.makeLines(diff, chunk.lines, comment_lists)
        listwalker = urwid.SimpleFocusListWalker(lines)
        self.listbox = urwid.ListBox(listwalker)
        self._w.contents.append((self.listbox, ('weight', 1)))
        self.old_focus = 2
        self.draft_comments = []
        self._w.set_focus(self.old_focus)
        self.handleUndisplayedComments(comment_lists)
        self.app.status.update(title=self.title)

    def handleUndisplayedComments(self, comment_lists):
        # Handle comments that landed outside our default diff context
        lastlen = 0
        while comment_lists:
            comment_lists_keys = list(comment_lists.keys())
            if len(comment_lists_keys) == lastlen:
                self.log.error("Unable to display all comments: %s" % comment_lists)
                return
            comment_lists_keys = list(comment_lists.keys())
            lastlen = len(comment_lists_keys)
            key = comment_lists_keys[0]
            kind, lineno, path = key.split('-', 2)
            lineno = int(lineno)
            if kind.startswith('old'):
                oldnew = gitrepo.OLD
            else:
                oldnew = gitrepo.NEW
            file_diffs = self.file_diffs[oldnew]
            if path not in file_diffs:
                self.log.error("Unable to display comment: %s" % key)
                del comment_lists[key]
                continue
            diff = self.file_diffs[oldnew][path]
            for chunk in diff.chunks:
                if (chunk.range[oldnew][gitrepo.START] <= lineno and
                    chunk.range[oldnew][gitrepo.END]   >= lineno):
                    i = chunk.indexOfLine(oldnew, lineno)
                    if i < (len(chunk.lines) / 2):
                        from_start = True
                    else:
                        from_start = False
                    if chunk.first and from_start:
                        from_start = False
                    if chunk.last and (not from_start):
                        from_start = True
                    if from_start:
                        self.expandChunk(diff, chunk, comment_lists, from_start=i+10)
                    else:
                        self.expandChunk(diff, chunk, comment_lists, from_end=0-(len(chunk.lines)-i)-10)
                    break

    def expandChunk(self, diff, chunk, comment_lists={}, from_start=None, from_end=None,
                    expand_all=None):
        self.log.debug("Expand chunk %s %s %s" % (chunk, from_start, from_end))
        add_lines = []
        if from_start is not None:
            index = self.listbox.body.index(chunk.button)
            add_lines = chunk.lines[:from_start]
            del chunk.lines[:from_start]
        if from_end is not None:
            index = self.listbox.body.index(chunk.button)+1
            add_lines = chunk.lines[from_end:]
            del chunk.lines[from_end:]
        if expand_all:
            index = self.listbox.body.index(chunk.button)
            add_lines = chunk.lines[:]
            del chunk.lines[:]
        if add_lines:
            lines = self.makeLines(diff, add_lines, comment_lists)
            self.listbox.body[index:index] = lines
        chunk.calcRange()
        if not chunk.lines:
            self.listbox.body.remove(chunk.button)
        else:
            chunk.button.update()

    def makeContext(self, diff, old_ln, new_ln, header=False):
        old_key = None
        new_key = None
        if not diff.old_empty:
            if diff.oldname in self.old_file_keys:
                old_key = self.old_file_keys[diff.oldname]
            elif diff.newname in self.old_file_keys:
                old_key = self.old_file_keys[diff.newname]
        if not diff.new_empty:
            new_key = self.new_file_keys.get(diff.newname)
        return LineContext(
            old_key, new_key,
            diff.oldname, diff.newname,
            old_ln, new_ln, header)

    def makeLines(self, diff, lines_to_add, comment_lists):
        raise NotImplementedError

    def makeFileHeader(self, diff, comment_lists):
        raise NotImplementedError

    def makeFileReminder(self):
        raise NotImplementedError

    def interested(self, event):
        if not ((isinstance(event, sync.ChangeAddedEvent) and
                 self.change_key in event.related_change_keys)
                or
                (isinstance(event, sync.ChangeUpdatedEvent) and
                 self.change_key in event.related_change_keys)):
            #self.log.debug("Ignoring refresh diff due to event %s" % (event,))
            return False
        #self.log.debug("Refreshing diff due to event %s" % (event,))
        return True

    def refresh(self, event=None):
        #TODO
        pass

    def getContextAtTop(self, size):
        middle, top, bottom = self.listbox.calculate_visible(size, True)
        if top and top[1]:
            (widget, pos, rows) = top[1][-1]
        elif middle:
            pos = middle[2]
        # Make sure the first header shows up as soon as it scrolls up
        if pos > 1:
            pos -= 1
        context = None
        while True:
            item = self.listbox.body[pos]
            if hasattr(item, 'context'):
                break
            pos -= 1
        if pos > 0:
            context = item.context
        return context

    def keypress(self, size, key):
        if self.searchKeypress(size, key):
            return None

        old_focus = self.listbox.focus
        if not self.app.input_buffer:
            key = super(BaseDiffView, self).keypress(size, key)
        new_focus = self.listbox.focus
        keys = self.app.input_buffer + [key]
        commands = self.app.config.keymap.getCommands(keys)

        context = self.getContextAtTop(size)
        if context:
            self.file_reminder.set(context.old_fn,
                                   context.new_fn)
        else:
            self.file_reminder.set('', '')

        if (isinstance(old_focus, BaseDiffCommentEdit) and
            (old_focus != new_focus or (keymap.PREV_SCREEN in commands))):
            self.cleanupEdit(old_focus)
        if keymap.SELECT_PATCHSETS in commands:
            self.openPatchsetDialog()
            return None
        if keymap.INTERACTIVE_SEARCH in commands:
            self.searchStart()
            return None
        return key

    def mouse_event(self, size, event, button, x, y, focus):
        old_focus = self.listbox.focus
        r = super(BaseDiffView, self).mouse_event(size, event, button, x, y, focus)
        new_focus = self.listbox.focus
        if old_focus != new_focus and isinstance(old_focus, BaseDiffCommentEdit):
            self.cleanupEdit(old_focus)
        return r

    def makeCommentEdit(self, edit):
        raise NotImplementedError

    def onSelect(self, button):
        pos = self.listbox.focus_position
        e = self.makeCommentEdit(self.listbox.body[pos])
        self.listbox.body.insert(pos+1, e)
        self.listbox.focus_position = pos+1

    def cleanupEdit(self, edit):
        raise NotImplementedError

    def deleteComment(self, comment_key):
        with self.app.db.getSession() as session:
            comment = session.getComment(comment_key)
            session.delete(comment)

    def saveComment(self, context, text, new=True):
        if (not new) and (not self.old_revision_num):
            parent = True
        else:
            parent = False
        if new:
            line_num = context.new_ln
            file_key = context.new_file_key
        else:
            line_num = context.old_ln
            file_key = context.old_file_key
        if file_key is None:
            raise Exception("Comment is not associated with a file")
        with self.app.db.getSession() as session:
            fileobj = session.getFile(file_key)
            account = session.getAccountByUsername(self.app.config.username)
            comment = fileobj.createComment(None, account, None,
                                            datetime.datetime.utcnow(),
                                            parent,
                                            line_num, text, draft=True)
            key = comment.key
        return key

    def openPatchsetDialog(self):
        revisions = []
        with self.app.db.getSession() as session:
            change = session.getChange(self.change_key)
            for r in change.revisions:
                revisions.append((r.key, r.number))
        dialog = PatchsetDialog(revisions,
                                self.old_revision_key,
                                self.new_revision_key)
        urwid.connect_signal(dialog, 'cancel',
            lambda button: self.app.backScreen())
        urwid.connect_signal(dialog, 'ok',
            lambda button: self._openPatchsetDialog(dialog))
        self.app.popup(dialog, min_width=30, min_height=8)

    def _openPatchsetDialog(self, dialog):
        self.app.backScreen()
        self.old_revision_key, self.new_revision_key = dialog.getSelected()
        self._init()