# git-gui branch merge support
# Copyright (C) 2006, 2007 Shawn Pearce

proc can_merge {} {
        global HEAD commit_type file_states

        if {[string match amend* $commit_type]} {
                info_popup {Cannot merge while amending.

You must finish amending this commit before starting any type of merge.
}
                return 0
        }

        if {[committer_ident] eq {}} {return 0}
        if {![lock_index merge]} {return 0}

        # -- Our in memory state should match the repository.
        #
        repository_state curType curHEAD curMERGE_HEAD
        if {$commit_type ne $curType || $HEAD ne $curHEAD} {
                info_popup {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 a merge can be performed.

The rescan will be automatically started now.
}
                unlock_index
                rescan {set ui_status_value {Ready.}}
                return 0
        }

        foreach path [array names file_states] {
                switch -glob -- [lindex $file_states($path) 0] {
                _O {
                        continue; # and pray it works!
                }
                U? {
                        error_popup "You are in the middle of a conflicted merge.

File [short_path $path] has merge conflicts.

You must resolve them, add the file, and commit to complete the current merge.  Only then can you begin another merge.
"
                        unlock_index
                        return 0
                }
                ?? {
                        error_popup "You are in the middle of a change.

File [short_path $path] is modified.

You should complete the current commit before starting a merge.  Doing so will help you abort a failed merge, should the need arise.
"
                        unlock_index
                        return 0
                }
                }
        }

        return 1
}

proc visualize_local_merge {w} {
        set revs {}
        foreach i [$w.source.l curselection] {
                lappend revs [$w.source.l get $i]
        }
        if {$revs eq {}} return
        lappend revs --not HEAD
        do_gitk $revs
}

proc start_local_merge_action {w} {
        global HEAD ui_status_value current_branch

        set cmd [list git merge]
        set names {}
        set revcnt 0
        foreach i [$w.source.l curselection] {
                set b [$w.source.l get $i]
                lappend cmd $b
                lappend names $b
                incr revcnt
        }

        if {$revcnt == 0} {
                return
        } elseif {$revcnt == 1} {
                set unit branch
        } elseif {$revcnt <= 15} {
                set unit branches

                if {[tk_dialog \
                $w.confirm_octopus \
                [wm title $w] \
                "Use octopus merge strategy?

You are merging $revcnt branches at once.  This requires using the octopus merge driver, which may not succeed if there are file-level conflicts.
" \
                question \
                0 \
                {Cancel} \
                {Use octopus} \
                ] != 1} return
        } else {
                tk_messageBox \
                        -icon error \
                        -type ok \
                        -title [wm title $w] \
                        -parent $w \
                        -message "Too many branches selected.

You have requested to merge $revcnt branches in an octopus merge.  This exceeds Git's internal limit of 15 branches per merge.

Please select fewer branches.  To merge more than 15 branches, merge the branches in batches.
"
                return
        }

        set msg "Merging $current_branch, [join $names {, }]"
        set ui_status_value "$msg..."
        set cons [new_console "Merge" $msg]
        console_exec $cons $cmd [list finish_merge $revcnt]
        bind $w <Destroy> {}
        destroy $w
}

proc finish_merge {revcnt w ok} {
        console_done $w $ok
        if {$ok} {
                set msg {Merge completed successfully.}
        } else {
                if {$revcnt != 1} {
                        info_popup "Octopus merge failed.

Your merge of $revcnt branches has failed.

There are file-level conflicts between the branches which must be resolved manually.

The working directory will now be reset.

You can attempt this merge again by merging only one branch at a time." $w

                        set fd [open "| git read-tree --reset -u HEAD" r]
                        fconfigure $fd -blocking 0 -translation binary
                        fileevent $fd readable [list reset_hard_wait $fd]
                        set ui_status_value {Aborting... please wait...}
                        return
                }

                set msg {Merge failed.  Conflict resolution is required.}
        }
        unlock_index
        rescan [list set ui_status_value $msg]
}

proc do_local_merge {} {
        global current_branch

        if {![can_merge]} return

        set w .merge_setup
        toplevel $w
        wm geometry $w "+[winfo rootx .]+[winfo rooty .]"

        label $w.header \
                -text "Merge Into $current_branch" \
                -font font_uibold
        pack $w.header -side top -fill x

        frame $w.buttons
        button $w.buttons.visualize -text Visualize \
                -command [list visualize_local_merge $w]
        pack $w.buttons.visualize -side left
        button $w.buttons.create -text Merge \
                -command [list start_local_merge_action $w]
        pack $w.buttons.create -side right
        button $w.buttons.cancel -text {Cancel} \
                -command [list destroy $w]
        pack $w.buttons.cancel -side right -padx 5
        pack $w.buttons -side bottom -fill x -pady 10 -padx 10

        labelframe $w.source -text {Source Branches}
        listbox $w.source.l \
                -height 10 \
                -width 70 \
                -selectmode extended \
                -yscrollcommand [list $w.source.sby set]
        scrollbar $w.source.sby -command [list $w.source.l yview]
        pack $w.source.sby -side right -fill y
        pack $w.source.l -side left -fill both -expand 1
        pack $w.source -fill both -expand 1 -pady 5 -padx 5

        set cmd [list git for-each-ref]
        lappend cmd {--format=%(objectname) %(*objectname) %(refname)}
        lappend cmd refs/heads
        lappend cmd refs/remotes
        lappend cmd refs/tags
        set fr_fd [open "| $cmd" r]
        fconfigure $fr_fd -translation binary
        while {[gets $fr_fd line] > 0} {
                set line [split $line { }]
                set sha1([lindex $line 0]) [lindex $line 2]
                set sha1([lindex $line 1]) [lindex $line 2]
        }
        close $fr_fd

        set to_show {}
        set fr_fd [open "| git rev-list --all --not HEAD"]
        while {[gets $fr_fd line] > 0} {
                if {[catch {set ref $sha1($line)}]} continue
                regsub ^refs/(heads|remotes|tags)/ $ref {} ref
                lappend to_show $ref
        }
        close $fr_fd

        foreach ref [lsort -unique $to_show] {
                $w.source.l insert end $ref
        }

        bind $w <Visibility> "grab $w"
        bind $w <Key-Escape> "unlock_index;destroy $w"
        bind $w <Destroy> unlock_index
        wm title $w "[appname] ([reponame]): Merge"
        tkwait window $w
}

proc do_reset_hard {} {
        global HEAD commit_type file_states

        if {[string match amend* $commit_type]} {
                info_popup {Cannot abort while amending.

You must finish amending this commit.
}
                return
        }

        if {![lock_index abort]} return

        if {[string match *merge* $commit_type]} {
                set op merge
        } else {
                set op commit
        }

        if {[ask_popup "Abort $op?

Aborting the current $op will cause *ALL* uncommitted changes to be lost.

Continue with aborting the current $op?"] eq {yes}} {
                set fd [open "| git read-tree --reset -u HEAD" r]
                fconfigure $fd -blocking 0 -translation binary
                fileevent $fd readable [list reset_hard_wait $fd]
                set ui_status_value {Aborting... please wait...}
        } else {
                unlock_index
        }
}

proc reset_hard_wait {fd} {
        global ui_comm

        read $fd
        if {[eof $fd]} {
                close $fd
                unlock_index

                $ui_comm delete 0.0 end
                $ui_comm edit modified false

                catch {file delete [gitdir MERGE_HEAD]}
                catch {file delete [gitdir rr-cache MERGE_RR]}
                catch {file delete [gitdir SQUASH_MSG]}
                catch {file delete [gitdir MERGE_MSG]}
                catch {file delete [gitdir GITGUI_MSG]}

                rescan {set ui_status_value {Abort completed.  Ready.}}
        }
}