# git-gui commit checkout support
# Copyright (C) 2007 Shawn Pearce

class checkout_op {

field w        {}; # our window (if we have one)
field w_cons   {}; # embedded console window object

field new_expr   ; # expression the user saw/thinks this is
field new_hash   ; # commit SHA-1 we are switching to
field new_ref    ; # ref we are updating/creating
field old_hash   ; # commit SHA-1 that was checked out when we started

field parent_w      .; # window that started us
field merge_type none; # type of merge to apply to existing branch
field merge_base   {}; # merge base if we have another ref involved
field fetch_spec   {}; # refetch tracking branch if used?
field checkout      1; # actually checkout the branch?
field create        0; # create the branch if it doesn't exist?
field remote_source {}; # same as fetch_spec, to setup tracking

field reset_ok      0; # did the user agree to reset?
field fetch_ok      0; # did the fetch succeed?

field readtree_d   {}; # buffered output from read-tree
field update_old   {}; # was the update-ref call deferred?
field reflog_msg   {}; # log message for the update-ref call

constructor new {expr hash {ref {}}} {
	set new_expr $expr
	set new_hash $hash
	set new_ref  $ref

	return $this
}

method parent {path} {
	set parent_w [winfo toplevel $path]
}

method enable_merge {type} {
	set merge_type $type
}

method enable_fetch {spec} {
	set fetch_spec $spec
}

method remote_source {spec} {
	set remote_source $spec
}

method enable_checkout {co} {
	set checkout $co
}

method enable_create {co} {
	set create $co
}

method run {} {
	if {$fetch_spec ne {}} {
		global M1B

		# We were asked to refresh a single tracking branch
		# before we get to work.  We should do that before we
		# consider any ref updating.
		#
		set fetch_ok 0
		set l_trck [lindex $fetch_spec 0]
		set remote [lindex $fetch_spec 1]
		set r_head [lindex $fetch_spec 2]
		regsub ^refs/heads/ $r_head {} r_name

		set cmd [list git fetch $remote]
		if {$l_trck ne {}} {
			lappend cmd +$r_head:$l_trck
		} else {
			lappend cmd $r_head
		}

		_toplevel $this {Refreshing Tracking Branch}
		set w_cons [::console::embed \
			$w.console \
			[mc "Fetching %s from %s" $r_name $remote]]
		pack $w.console -fill both -expand 1
		$w_cons exec $cmd [cb _finish_fetch]

		bind $w <$M1B-Key-w> break
		bind $w <$M1B-Key-W> break
		bind $w <Visibility> "
			[list grab $w]
			[list focus $w]
		"
		wm protocol $w WM_DELETE_WINDOW [cb _noop]
		tkwait window $w

		if {!$fetch_ok} {
			delete_this
			return 0
		}
	}

	if {$new_ref ne {}} {
		# If we have a ref we need to update it before we can
		# proceed with a checkout (if one was enabled).
		#
		if {![_update_ref $this]} {
			delete_this
			return 0
		}
	}

	if {$checkout} {
		_checkout $this
		return 1
	}

	delete_this
	return 1
}

method _noop {} {}

method _finish_fetch {ok} {
	if {$ok} {
		set l_trck [lindex $fetch_spec 0]
		if {$l_trck eq {}} {
			set l_trck FETCH_HEAD
		}
		if {[catch {set new_hash [git rev-parse --verify "$l_trck^0"]} err]} {
			set ok 0
			$w_cons insert [mc "fatal: Cannot resolve %s" $l_trck]
			$w_cons insert $err
		}
	}

	$w_cons done $ok
	set w_cons {}
	wm protocol $w WM_DELETE_WINDOW {}

	if {$ok} {
		destroy $w
		set w {}
	} else {
		button $w.close -text [mc Close] -command [list destroy $w]
		pack $w.close -side bottom -anchor e -padx 10 -pady 10
	}

	set fetch_ok $ok
}

method _update_ref {} {
	global null_sha1 current_branch repo_config

	set ref $new_ref
	set new $new_hash

	set is_current 0
	set rh refs/heads/
	set rn [string length $rh]
	if {[string equal -length $rn $rh $ref]} {
		set newbranch [string range $ref $rn end]
		if {$current_branch eq $newbranch} {
			set is_current 1
		}
	} else {
		set newbranch $ref
	}

	if {[catch {set cur [git rev-parse --verify "$ref^0"]}]} {
		# Assume it does not exist, and that is what the error was.
		#
		if {!$create} {
			_error $this [mc "Branch '%s' does not exist." $newbranch]
			return 0
		}

		set reflog_msg "branch: Created from $new_expr"
		set cur $null_sha1

		if {($repo_config(branch.autosetupmerge) eq {true}
			|| $repo_config(branch.autosetupmerge) eq {always})
			&& $remote_source ne {}
			&& "refs/heads/$newbranch" eq $ref} {

			set c_remote [lindex $remote_source 1]
			set c_merge [lindex $remote_source 2]
			if {[catch {
					git config branch.$newbranch.remote $c_remote
					git config branch.$newbranch.merge  $c_merge
				} err]} {
				_error $this [strcat \
				[mc "Failed to configure simplified git-pull for '%s'." $newbranch] \
				"\n\n$err"]
			}
		}
	} elseif {$create && $merge_type eq {none}} {
		# We were told to create it, but not do a merge.
		# Bad.  Name shouldn't have existed.
		#
		_error $this [mc "Branch '%s' already exists." $newbranch]
		return 0
	} elseif {!$create && $merge_type eq {none}} {
		# We aren't creating, it exists and we don't merge.
		# We are probably just a simple branch switch.
		# Use whatever value we just read.
		#
		set new      $cur
		set new_hash $cur
	} elseif {$new eq $cur} {
		# No merge would be required, don't compute anything.
		#
	} else {
		catch {set merge_base [git merge-base $new $cur]}
		if {$merge_base eq $cur} {
			# The current branch is older.
			#
			set reflog_msg "merge $new_expr: Fast-forward"
		} else {
			switch -- $merge_type {
			ff {
				if {$merge_base eq $new} {
					# The current branch is actually newer.
					#
					set new $cur
					set new_hash $cur
				} else {
					_error $this [mc "Branch '%s' already exists.\n\nIt cannot fast-forward to %s.\nA merge is required." $newbranch $new_expr]
					return 0
				}
			}
			reset {
				# The current branch will lose things.
				#
				if {[_confirm_reset $this $cur]} {
					set reflog_msg "reset $new_expr"
				} else {
					return 0
				}
			}
			default {
				_error $this [mc "Merge strategy '%s' not supported." $merge_type]
				return 0
			}
			}
		}
	}

	if {$new ne $cur} {
		if {$is_current} {
			# No so fast.  We should defer this in case
			# we cannot update the working directory.
			#
			set update_old $cur
			return 1
		}

		if {[catch {
				git update-ref -m $reflog_msg $ref $new $cur
			} err]} {
			_error $this [strcat [mc "Failed to update '%s'." $newbranch] "\n\n$err"]
			return 0
		}
	}

	return 1
}

method _checkout {} {
	if {[lock_index checkout_op]} {
		after idle [cb _start_checkout]
	} else {
		_error $this [mc "Staging area (index) is already locked."]
		delete_this
	}
}

method _start_checkout {} {
	global HEAD commit_type

	# -- Our in memory state should match the repository.
	#
	repository_state curType old_hash curMERGE_HEAD
	if {[string match amend* $commit_type]
		&& $curType eq {normal}
		&& $old_hash eq $HEAD} {
	} elseif {$commit_type ne $curType || $HEAD ne $old_hash} {
		info_popup [mc "Last scanned state does not match repository state.

Another Git program has modified this repository since the last scan.  A rescan must be performed before the current branch can be changed.

The rescan will be automatically started now.
"]
		unlock_index
		rescan ui_ready
		delete_this
		return
	}

	if {$old_hash eq $new_hash} {
		_after_readtree $this
	} elseif {[is_config_true gui.trustmtime]} {
		_readtree $this
	} else {
		ui_status [mc "Refreshing file status..."]
		set fd [git_read [list update-index \
			-q \
			--unmerged \
			--ignore-missing \
			--refresh \
			]]
		fconfigure $fd -blocking 0 -translation binary
		fileevent $fd readable [cb _refresh_wait $fd]
	}
}

method _refresh_wait {fd} {
	read $fd
	if {[eof $fd]} {
		close $fd
		_readtree $this
	}
}

method _name {} {
	if {$new_ref eq {}} {
		return [string range $new_hash 0 7]
	}

	set rh refs/heads/
	set rn [string length $rh]
	if {[string equal -length $rn $rh $new_ref]} {
		return [string range $new_ref $rn end]
	} else {
		return $new_ref
	}
}

method _readtree {} {
	global HEAD

	set readtree_d {}
	set status_bar_operation [$::main_status start \
		[mc "Updating working directory to '%s'..." [_name $this]] \
		[mc "files checked out"]]

	set fd [git_read [list read-tree \
		-m \
		-u \
		-v \
		--exclude-per-directory=.gitignore \
		$HEAD \
		$new_hash \
		] \
		[list 2>@1]]
	fconfigure $fd -blocking 0 -translation binary
	fileevent $fd readable [cb _readtree_wait $fd $status_bar_operation]
}

method _readtree_wait {fd status_bar_operation} {
	global current_branch

	set buf [read $fd]
	$status_bar_operation update_meter $buf
	append readtree_d $buf

	fconfigure $fd -blocking 1
	if {![eof $fd]} {
		fconfigure $fd -blocking 0
		$status_bar_operation stop
		return
	}

	if {[catch {close $fd}]} {
		set err $readtree_d
		regsub {^fatal: } $err {} err
		$status_bar_operation stop [mc "Aborted checkout of '%s' (file level merging is required)." [_name $this]]
		warn_popup [strcat [mc "File level merge required."] "

$err

" [mc "Staying on branch '%s'." $current_branch]]
		unlock_index
		delete_this
		return
	}

	$status_bar_operation stop
	_after_readtree $this
}

method _after_readtree {} {
	global commit_type HEAD MERGE_HEAD PARENT
	global current_branch is_detached
	global ui_comm

	set name [_name $this]
	set log "checkout: moving"
	if {!$is_detached} {
		append log " from $current_branch"
	}

	# -- Move/create HEAD as a symbolic ref.  Core git does not
	#    even check for failure here, it Just Works(tm).  If it
	#    doesn't we are in some really ugly state that is difficult
	#    to recover from within git-gui.
	#
	set rh refs/heads/
	set rn [string length $rh]
	if {[string equal -length $rn $rh $new_ref]} {
		set new_branch [string range $new_ref $rn end]
		if {$is_detached || $current_branch ne $new_branch} {
			append log " to $new_branch"
			if {[catch {
					git symbolic-ref -m $log HEAD $new_ref
				} err]} {
				_fatal $this $err
			}
			set current_branch $new_branch
			set is_detached 0
		}
	} else {
		if {!$is_detached || $new_hash ne $HEAD} {
			append log " to $new_expr"
			if {[catch {
					_detach_HEAD $log $new_hash
				} err]} {
				_fatal $this $err
			}
		}
		set current_branch HEAD
		set is_detached 1
	}

	# -- We had to defer updating the branch itself until we
	#    knew the working directory would update.  So now we
	#    need to finish that work.  If it fails we're in big
	#    trouble.
	#
	if {$update_old ne {}} {
		if {[catch {
				git update-ref \
					-m $reflog_msg \
					$new_ref \
					$new_hash \
					$update_old
			} err]} {
			_fatal $this $err
		}
	}

	if {$is_detached} {
		info_popup [mc "You are no longer on a local branch.

If you wanted to be on a branch, create one now starting from 'This Detached Checkout'."]
	}

	# -- Run the post-checkout hook.
	#
	set fd_ph [githook_read post-checkout $old_hash $new_hash 1]
	if {$fd_ph ne {}} {
		global pch_error
		set pch_error {}
		fconfigure $fd_ph -blocking 0 -translation binary -eofchar {}
		fileevent $fd_ph readable [cb _postcheckout_wait $fd_ph]
	} else {
		_update_repo_state $this
	}
}

method _postcheckout_wait {fd_ph} {
	global pch_error

	append pch_error [read $fd_ph]
	fconfigure $fd_ph -blocking 1
	if {[eof $fd_ph]} {
		if {[catch {close $fd_ph}]} {
			hook_failed_popup post-checkout $pch_error 0
		}
		unset pch_error
		_update_repo_state $this
		return
	}
	fconfigure $fd_ph -blocking 0
}

method _update_repo_state {} {
	# -- Update our repository state.  If we were previously in
	#    amend mode we need to toss the current buffer and do a
	#    full rescan to update our file lists.  If we weren't in
	#    amend mode our file lists are accurate and we can avoid
	#    the rescan.
	#
	global commit_type_is_amend commit_type HEAD MERGE_HEAD PARENT
	global ui_comm

	unlock_index
	set name [_name $this]
	set commit_type_is_amend 0
	if {[string match amend* $commit_type]} {
		$ui_comm delete 0.0 end
		$ui_comm edit reset
		$ui_comm edit modified false
		rescan [list ui_status [mc "Checked out '%s'." $name]]
	} else {
		repository_state commit_type HEAD MERGE_HEAD
		set PARENT $HEAD
		ui_status [mc "Checked out '%s'." $name]
	}
	delete_this
}

proc _detach_HEAD {log new} {
	git update-ref --no-deref -m $log HEAD $new
}

method _confirm_reset {cur} {
	set reset_ok 0
	set name [_name $this]
	set gitk [list do_gitk [list $cur ^$new_hash]]

	_toplevel $this {Confirm Branch Reset}
	pack [label $w.msg1 \
		-anchor w \
		-justify left \
		-text [mc "Resetting '%s' to '%s' will lose the following commits:" $name $new_expr]\
		] -anchor w

	set list $w.list.l
	frame $w.list
	text $list \
		-font font_diff \
		-width 80 \
		-height 10 \
		-wrap none \
		-xscrollcommand [list $w.list.sbx set] \
		-yscrollcommand [list $w.list.sby set]
	scrollbar $w.list.sbx -orient h -command [list $list xview]
	scrollbar $w.list.sby -orient v -command [list $list yview]
	pack $w.list.sbx -fill x -side bottom
	pack $w.list.sby -fill y -side right
	pack $list -fill both -expand 1
	pack $w.list -fill both -expand 1 -padx 5 -pady 5

	pack [label $w.msg2 \
		-anchor w \
		-justify left \
		-text [mc "Recovering lost commits may not be easy."] \
		]
	pack [label $w.msg3 \
		-anchor w \
		-justify left \
		-text [mc "Reset '%s'?" $name] \
		]

	frame $w.buttons
	button $w.buttons.visualize \
		-text [mc Visualize] \
		-command $gitk
	pack $w.buttons.visualize -side left
	button $w.buttons.reset \
		-text [mc Reset] \
		-command "
			set @reset_ok 1
			destroy $w
		"
	pack $w.buttons.reset -side right
	button $w.buttons.cancel \
		-default active \
		-text [mc Cancel] \
		-command [list destroy $w]
	pack $w.buttons.cancel -side right -padx 5
	pack $w.buttons -side bottom -fill x -pady 10 -padx 10

	set fd [git_read [list rev-list --pretty=oneline $cur ^$new_hash]]
	while {[gets $fd line] > 0} {
		set abbr [string range $line 0 7]
		set subj [string range $line 41 end]
		$list insert end "$abbr  $subj\n"
	}
	close $fd
	$list configure -state disabled

	bind $w    <Key-v> $gitk
	bind $w <Visibility> "
		grab $w
		focus $w.buttons.cancel
	"
	bind $w <Key-Return> [list destroy $w]
	bind $w <Key-Escape> [list destroy $w]
	tkwait window $w
	return $reset_ok
}

method _error {msg} {
	if {[winfo ismapped $parent_w]} {
		set p $parent_w
	} else {
		set p .
	}

	tk_messageBox \
		-icon error \
		-type ok \
		-title [wm title $p] \
		-parent $p \
		-message $msg
}

method _toplevel {title} {
	regsub -all {::} $this {__} w
	set w .$w

	if {[winfo ismapped $parent_w]} {
		set p $parent_w
	} else {
		set p .
	}

	toplevel $w
	wm title $w $title
	wm geometry $w "+[winfo rootx $p]+[winfo rooty $p]"
}

method _fatal {err} {
	error_popup [strcat [mc "Failed to set current branch.

This working directory is only partially switched.  We successfully updated your files, but failed to update an internal Git file.

This should not have occurred.  %s will now close and give up." [appname]] "

$err"]
	exit 1
}

}
