### Retire a slot: strip it from the pipelines and delete its objects from S3.
#
# Usage:
#   Rscript local/retire-slot.R <codename> [--apply] [--config-only|--assets-only]
#
#   Rscript local/retire-slot.R alpine322                 # dry run, both halves
#   Rscript local/retire-slot.R alpine322 --config-only    # edit .crow/, no S3
#   Rscript local/retire-slot.R alpine322 --assets-only --apply
#
# Retiring a distro retires both architectures, because `local.rpkgs_slots` in
# `cdn.tf` is a setproduct over `["amd64", "arm64"]` and there is no way to
# publish one without the other.
#
# Three things have to happen and nothing ties them together on its own:
#
#   1. the slot leaves `local.rpkgs_slots` in `cdn.tf` (and `DistroId` in the
#      website's `src/src/data/repos.ts`), which is what stops the edge routing
#      it. Do this first and by hand: it is the decision, the rest is cleanup.
#   2. the slot leaves every `.crow/*.yaml` matrix, which is what stops the
#      fleet building, indexing and verifying it. This script does that.
#   3. the objects leave the bucket. This script does that too.
#
# A fourth step cannot be scripted from here: the slot's cron jobs live on the
# Crow server, not in this repository, and removing a matrix row does not remove
# the cron that targets it. The script prints the ones it finds by name at the
# end, with the API call to delete them.
#
# Dry run by default. Nothing is edited or deleted without --apply.
#
# Order matters. Deleting the objects while a pipeline still targets the slot
# means the next nightly rebuilds them.
#
# Only structural YAML is edited: matrix rows, dropdown options and the
# `OS_VERSION` tag. Prose that happens to mention the slot (a usage example in
# a header comment, a dropdown `description:`) is left alone, because rewriting
# free text automatically is guesswork. Grep for the name afterwards.

options(error = function() {
  cat("ERROR:", geterrmessage(), "\n", file = stdout())
  q(status = 1)
})

args <- commandArgs(trailingOnly = TRUE)
apply_changes <- "--apply" %in% args
config_only <- "--config-only" %in% args
assets_only <- "--assets-only" %in% args
args <- args[!args %in% c("--apply", "--config-only", "--assets-only")]
if (length(args) != 1L || (config_only && assets_only)) {
  stop(
    "usage: retire-slot.R <codename> [--apply] [--config-only|--assets-only]",
    call. = FALSE
  )
}
codename <- args[[1L]]

# `alpine322` is how the bucket, the edge and `CODENAME:` spell it; `alpine-322`
# is how `OS:` and the dropdown options spell it. Both have to go.
pipeline_os <- if (grepl("^rhel[0-9]+$", codename)) {
  sub("^rhel", "redhat-", codename)
} else if (grepl("^alpine[0-9]+$", codename)) {
  sub("^alpine", "alpine-", codename)
} else {
  # Single bracket, so an unknown codename yields NA and the check below
  # reports it rather than raising "subscript out of bounds".
  c(resolute = "ubuntu-2604", noble = "ubuntu-2404", jammy = "ubuntu-2204")[
    codename
  ]
}
if (is.na(pipeline_os) || length(pipeline_os) == 0L) {
  stop(sprintf("Unrecognised codename '%s'.", codename), call. = FALSE)
}

# The `OS_VERSION` dropdowns are keyed on the image tag, not the slot name.
image_tag <- if (grepl("^alpine-", pipeline_os)) {
  sub("^alpine-([0-9])([0-9]+)$", "\\1.\\2", pipeline_os)
} else if (grepl("^redhat-", pipeline_os)) {
  sub("^redhat-", "", pipeline_os)
} else {
  codename
}

# Refuse to retire a slot that is still routed. Without this the script is a
# fast way to break a live slot: the edge would keep sending clients to indexes
# whose objects no longer exist, and every install would 404.
tf <- readLines("cdn.tf", warn = FALSE)
start <- grep("rpkgs_slots\\s*=", tf)
if (length(start) != 1L) {
  stop(
    "Could not find exactly one `rpkgs_slots` local in cdn.tf.",
    call. = FALSE
  )
}
block <- paste(tf[start:min(start + 10L, length(tf))], collapse = "\n")
if (grepl(sprintf('"%s"', codename), block, fixed = TRUE)) {
  stop(
    sprintf(
      "'%s' is still listed in `local.rpkgs_slots` in cdn.tf, so the edge still routes it. Remove it there (and from the website's DistroId union) and apply the OpenTofu change first.", # nolint
      codename
    ),
    call. = FALSE
  )
}

cat(sprintf(
  "Retiring %s (pipelines call it '%s', images tag it '%s')\n\n",
  codename,
  pipeline_os,
  image_tag
))

## 1. Pipeline definitions ----------------------------------------------------

# Drops a matrix row and everything indented under it, a dropdown option, and
# an `OS_VERSION` entry for the retired tag. Line-based on purpose: round
# tripping through a YAML parser would reflow all 18 files and bury the change.
strip_slot <- function(lines) {
  keep <- rep(TRUE, length(lines))
  i <- 1L
  while (i <= length(lines)) {
    line <- lines[[i]]
    row <- regexec(
      sprintf(
        "^(\\s*)-\\s*(OS|CODENAME):\\s*(%s|%s)\\s*$",
        pipeline_os,
        codename
      ),
      line
    )
    m <- regmatches(line, row)[[1L]]
    if (length(m) == 4L) {
      indent <- nchar(m[[2L]])
      keep[[i]] <- FALSE
      j <- i + 1L
      while (j <= length(lines)) {
        nxt <- lines[[j]]
        if (
          !nzchar(trimws(nxt)) || nchar(sub("^(\\s*).*$", "\\1", nxt)) <= indent
        ) {
          break
        }
        keep[[j]] <- FALSE
        j <- j + 1L
      }
      i <- j
      next
    }
    if (grepl(sprintf("^\\s*-\\s*%s-(amd64|arm64)\\s*$", pipeline_os), line)) {
      keep[[i]] <- FALSE
    }
    if (grepl(sprintf("^\\s*-\\s*'%s'\\s*$", image_tag), line)) {
      keep[[i]] <- FALSE
    }
    i <- i + 1L
  }
  out <- lines[keep]
  # A dropdown whose default was the retired tag would reject its own default,
  # so move it to the first surviving option of the same block.
  bad_default <- grepl(sprintf("^\\s*default:\\s*'%s'\\s*$", image_tag), out)
  if (any(bad_default)) {
    for (k in which(bad_default)) {
      opts <- grep("^\\s*-\\s*'[^']+'\\s*$", out[seq_len(k - 1L)])
      if (length(opts) == 0L) {
        next
      }
      # Walk back to the first option of this block rather than the last, so the
      # default lands on the lowest surviving version instead of an unrelated one.
      first <- max(opts)
      while (first > 1L && grepl("^\\s*-\\s*'[^']+'\\s*$", out[[first - 1L]])) {
        first <- first - 1L
      }
      replacement <- sub("^\\s*-\\s*'([^']+)'\\s*$", "\\1", out[[first]])
      out[[k]] <- sub("'[^']+'", sprintf("'%s'", replacement), out[[k]])
      cat(sprintf("  default moved to '%s'\n", replacement))
    }
  }
  out
}

if (!assets_only) {
  files <- sort(list.files(".crow", pattern = "\\.yaml$", full.names = TRUE))
  touched <- 0L
  for (f in files) {
    lines <- readLines(f, warn = FALSE)
    out <- strip_slot(lines)
    if (length(out) == length(lines)) {
      next
    }
    touched <- touched + 1L
    cat(sprintf(
      "  %s %-45s -%d lines\n",
      if (apply_changes) "EDIT   " else "would edit",
      f,
      length(lines) - length(out)
    ))
    if (apply_changes) {
      writeLines(out, f)
    }
  }
  if (touched == 0L) {
    cat("  No pipeline references the slot.\n")
  } else if (apply_changes) {
    cat(sprintf(
      "  %d file(s) edited. Verify with `crow lint .crow/` and `Rscript local/check-slots.R`.\n",
      touched
    ))
  }
  cat("\n")
}

## 2. Bucket objects ----------------------------------------------------------

if (!config_only) {
  library(s3fs, quietly = TRUE)
  if (!nzchar(Sys.getenv("B2_S3_ACCESS_KEY"))) {
    stop(
      "B2_S3_ACCESS_KEY is unset. B2 needs credentials even to list, and an unauthenticated list returns empty, which is indistinguishable from an already-clean slot.", # nolint
      call. = FALSE
    )
  }
  bucket <- "devxy-rpkgs-binaries"
  s3fs::s3_file_system(
    aws_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"),
    aws_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"),
    endpoint = "https://s3.eu-central-003.backblazeb2.com",
    region_name = "eu-central-003",
    refresh = TRUE
  )

  for (arch in c("amd64", "arm64")) {
    prefix <- sprintf("%s/%s/%s", bucket, arch, codename)
    if (!s3fs::s3_dir_exists(prefix)) {
      cat(sprintf("  %s/%s: nothing in the bucket.\n", arch, codename))
      next
    }
    objects <- s3fs::s3_dir_ls(prefix, recurse = TRUE)
    cat(sprintf(
      "  %s %s/%s: %d object(s)\n",
      if (apply_changes) "DELETE" else "would delete",
      arch,
      codename,
      length(objects)
    ))
    if (apply_changes && length(objects) > 0L) {
      s3fs::s3_dir_delete(prefix)
      cat(sprintf("  deleted s3://%s\n", prefix))
    }
  }
  cat("\n")
}

## 3. What is left for a human ------------------------------------------------

if (!apply_changes) {
  cat("Dry run: nothing was edited or deleted. Re-run with --apply.\n\n")
}

cat("Crons still to remove on the Crow server (they are not in this repo):\n")
cat(sprintf(
  "  crow-at ci.devxy.io repo cron ls devxy/build-cran-binaries | grep %s\n",
  pipeline_os
))
cat(
  "  # `crow repo cron rm` 404s on this server version; use the API, whose base is /api/v1\n"
)
cat("  eval \"$(crow-at --export ci.devxy.io)\"\n")
cat("  curl -s -X DELETE -H \"Authorization: Bearer $CROW_TOKEN\" \\\n")
cat("    https://ci.devxy.io/api/v1/repos/5/cron/<cron-id>\n")