#!/usr/bin/env bash
set -Eeuo pipefail

# There is no button in the interface of GitHub (and as it seems also no API) with which workflows can be deleted.
# They are eventually removed automatically, but in case you want to clean up your Actions UI it is sometimes nice
# to have the possibility to get rid of workflows that are not required anymore. This interactive script allows you
# to achieve exactly that by deleting each individual run of a workflow, after which GitHub deletes the workflow.

declare -ir CONCURRENCY=${CONCURRENCY:-8}

# region https://no-color.org/
if [[ "${NO_COLOR:-}" == '' ]]; then
    readonly RESET='\033[0m'
    readonly DIM='\033[2m'
    readonly RESET_DIM='\033[22m'
    readonly BOLD='\033[1m'
    readonly RESET_BOLD='\033[22m'
    readonly CYAN='\033[36m'
    readonly RED='\033[31m'
    readonly GREEN='\033[32m'
else
    readonly RESET=
    readonly DIM=
    readonly RESET_DIM=
    readonly BOLD=
    readonly RESET_BOLD=
    readonly CYAN=
    readonly RED=
    readonly GREEN=
fi
# endregion

dry_run=false
yes=false
while (($# > 0)); do
    case "$1" in
    -d | --dry-run)
        dry_run=true
        ;;

    -h | --help)
        cat <<HELP
Delete GitHub Actions Workflows from this repository.

Usage: gh-delete-workflow [option]...

Options:
  -d --dry-run  Print what would be deleted, but do not delete anything.
  -h --help     Show this help and exit.
  -y --yes      I know what I am doing, stop asking me questions!

Environment:
  CONCURRENCY=$CONCURRENCY  Sets the concurrency level for requests.
HELP
        exit 0
        ;;

    -y | --yes)
        yes=true
        ;;

    --)
        break
        ;;
    -*)
        printf -- '%bUnknown option: %s%b\n' "$RED" "$1" "$RESET"
        ;;
    *)
        break
        ;;
    esac
    shift
done
readonly dry_run yes

if ! command -v gh &>/dev/null; then
    printf -- '%bCould not find gh in PATH, make sure it is available: https://cli.github.com/%b\n' "$RED" "$RESET" >&2
    exit 1
fi

workflow_names=()
workflow_paths=()
workflow_ids=()
while read -r workflow; do
    eval "$workflow"
done < <(gh api '/repos/{owner}/{repo}/actions/workflows' --jq '.workflows |= sort_by(.name) | .workflows[] | "workflow_names+=('"'"'\(.name)'"'"');workflow_paths+=('"'"'\(.path)'"'"');workflow_ids+=(\(.id))"')

case ${#workflow_names[@]} in
0)
    echo 'Nothing to delete, this repository does not have any workflows.'
    exit 0
    ;;

1)
    readonly workflow_name=${workflow_names[0]}
    readonly workflow_path=${workflow_paths[0]}
    readonly workflow_id=${workflow_ids[0]}
    printf 'There is only one workflow %b%s %b(%s)%b...\n' "$CYAN" "$workflow_name" "$DIM" "$workflow_id" "$RESET"
    ;;

*)
    for ((i = 0; i < ${#workflow_names[@]}; i++)); do
        printf -- '%b[%i]%b %s %b%s (%s)%b\n' "$CYAN" $((i + 1)) "$RESET" "${workflow_names[$i]}" "$DIM" "${workflow_paths[$i]}" "${workflow_ids[$i]}" "$RESET_DIM"
    done

    while :; do
        printf -- '%bWhich workflow [1..%i]? ' "$CYAN" ${#workflow_names[@]}
        read -r selection
        if ((1 <= selection && selection <= ${#workflow_names[@]})); then
            printf -- "%b" "$RESET"
            ((selection--))
            readonly selection
            break
        else
            # shellcheck disable=SC2016
            printf -- '%bSelection `%s` is invalid, %bMUST%b be one of [1..%i], try again...%b\n' "$RED" "$selection" "$BOLD" "$RESET_BOLD" "${#workflow_names[@]}" "$RESET" >&2
        fi
    done

    readonly workflow_name=${workflow_names[$selection]}
    readonly workflow_path=${workflow_paths[$selection]}
    readonly workflow_id=${workflow_ids[$selection]}
    ;;
esac
unset workflow_names workflow_ids

if [[ "$dry_run" == false && "$yes" == false ]]; then
    # shellcheck disable=SC2016
    printf -- 'Are you sure you want to delete workflow %b%s %b%s (%s)%b? %bYou cannot recover from this!%b [y/n] ' "$CYAN" "$workflow_name" "$DIM" "$workflow_path" "$workflow_id" "$RESET" "$RED" "$RESET"
    read -rN1 reply
    if [[ "$reply" != y ]]; then
        case "$reply" in
        n) response='\nOK' ;;
        $'\n') response='You did not enter anything' ;;
        *) response='\nAssuming you meant n' ;;
        esac
        printf -- '%b%b, aborting...%b\n' "$RED" "$response" "$RESET"
        exit 0
    fi
    unset reply
    echo
fi

i=0
while read -r run_id; do
    if [[ "$dry_run" == true ]]; then
        printf -- '%b💀 run %s%b\n' "$RED" "$run_id" "$RESET"
    else
        gh api -X DELETE "/repos/{owner}/{repo}/actions/runs/$run_id" &
    fi
    if ((++i == CONCURRENCY)); then
        i=0
        wait
    fi
done < <(gh api --paginate "/repos/{owner}/{repo}/actions/workflows/$workflow_id/runs" --jq '.workflow_runs[] | .id')
wait
printf -- '%bDone%b\n' "$GREEN" "$RESET"