Write-Output "Moony's upstream merge workflow tool."
Write-Output "This tool can be stopped at any time, i.e. to finish a merge or resolve conflicts. Simply rerun the tool after having resolved the merge with normal git cli."
Write-Output "Pay attention to any output from git! DO NOT RUN THIS ON A WORKING TREE WITH UNCOMMITTED FILES OF ANY KIND."
$target = Read-Host "Enter the branch you're syncing toward (typically upstream/master or similar)"
$refs = git log --reverse --format=format:%H HEAD.. $target

$cherryPickOption = New-Object System.Management.Automation.Host.ChoiceDescription "&Cherry-pick","Uses git cherry pick to integrate the commit into the current branch. BE VERY CAREFUL WITH THIS."
$mergeOption = New-Object System.Management.Automation.Host.ChoiceDescription "&Merge","Uses git merge to integrate the commit and any of it's children into the current branch."
$skipOption = New-Object System.Management.Automation.Host.ChoiceDescription "&Skip","Skips introducing this commit."

$mergeOptions = [System.Management.Automation.Host.ChoiceDescription[]]($skipOption, $mergeOption, $cherryPickOption)

foreach ($unmerged in $refs) {
    $summary = git show --format=format:%s $unmerged

    if ($summary -ieq "automatic changelog update") {
        Write-Output ("Deliberately skipping changelog bot commit {0}." -f $unmerged)
        Write-Output "== GIT (CONFLICTS ARE OKAY) =="
        git merge --no-ff --no-commit --no-verify $unmerged
        # DELIBERATELY IGNORE merge conflict markers. We're just going to undo the commit!
        git add *
        git commit -m ("squash! Merge tool skipping '{0}'" -f $unmerged)
        $newhead = git log -n 1 --format=format:%H
        git reset HEAD~ --hard
        git reset $newhead --soft
        git commit --amend --no-edit
        Write-Output "== DONE =="
        continue
    }

    git show --format=full --summary $unmerged

    $response = $host.UI.PromptForChoice("Commit action?", "", $mergeOptions, 0)

    Switch ($response) {
        2 {
            Write-Output "== GIT =="
            git cherry-pick $unmerged
            Write-Output "== DONE =="
        }
        1 {
            Write-Output "== GIT =="
            git merge --no-ff -m ("squash! Merge tool integrating '{0}'" -f $unmerged) $unmerged
            Write-Output "== DONE =="
        }
        0 {
            Write-Output ("Skipping {0}" -f $unmerged)
            Write-Output "== GIT (CONFLICTS ARE OKAY) =="
            git merge --no-ff --no-commit --no-verify $unmerged
            # DELIBERATELY IGNORE merge conflict markers. We're just going to undo the commit!
            git add *
            git commit -m ("squash! Merge tool skipping '{0}'" -f $unmerged)
            $newhead = git log -n 1 --format=format:%H
            git reset HEAD~ --hard
            git reset $newhead --soft
            git commit --amend --no-edit
            Write-Output "== DONE =="
        }
    }
}

# TODO: squash all merges together.