# 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 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 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 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

        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 $null_sha1
        } elseif {$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 curHEAD curMERGE_HEAD
        if {[string match amend* $commit_type]
                && $curType eq {normal}
                && $curHEAD eq $HEAD} {
        } elseif {$commit_type ne $curType || $HEAD ne $curHEAD} {
                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 {$curHEAD 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 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 {}
        $::main_status start \
                [mc "Updating working directory to '%s'..." [_name $this]] \
                [mc "files checked out"]

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

method _readtree_wait {fd} {
        global current_branch

        set buf [read $fd]
        $::main_status update_meter $buf
        append readtree_d $buf

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

        if {[catch {close $fd}]} {
                set err $readtree_d
                regsub {^fatal: } $err {} err
                $::main_status 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
        }

        $::main_status stop
        _after_readtree $this
}

method _after_readtree {} {
        global selected_commit_type 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'."]
        }

        # -- 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.
        #
        unlock_index
        set selected_commit_type new
        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
}

git-version proc _detach_HEAD {log new} {
        >= 1.5.3 {
                git update-ref --no-deref -m $log HEAD $new
        }
        default {
                set p [gitdir HEAD]
                file delete $p
                set fd [open $p w]
                fconfigure $fd -translation lf -encoding utf-8
                puts $fd $new
                close $fd
        }
}

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 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
}

}