#!/usr/bin/env bash
# Update the kdlbs/homebrew-kandev tap with a new formula for the given release.
#
# Downloads .sha256 files from the GitHub release to populate the formula,
# generates Formula/kandev.rb, and pushes (or opens a PR).
#
# Usage:
#   update-homebrew-tap.sh <version> <tag>
#
# Arguments:
#   version  SemVer string (e.g. 0.17.0)
#   tag      Git tag (e.g. v0.17.0)
#
# Environment:
#   HOMEBREW_TAP_REPO         Override tap repo (default: kdlbs/homebrew-kandev).
#   HOMEBREW_TAP_DEPLOY_KEY   Private SSH key (PEM) for the tap repo. When set,
#                             clone via SSH and push directly to main. This is
#                             the default CI path. Deploy keys cannot open PRs.
#   HOMEBREW_TAP_PUSH         When no deploy key is present, set to "1" to push
#                             directly via `gh`/HTTPS instead of opening a PR.
set -euo pipefail

VERSION="${1:?Usage: $0 <version> <tag>}"
TAG="${2:?Usage: $0 <version> <tag>}"
TAP_REPO="${HOMEBREW_TAP_REPO:-kdlbs/homebrew-kandev}"
PUSH_DIRECT="${HOMEBREW_TAP_PUSH:-0}"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
FORMULA_TEMPLATE="$SCRIPT_DIR/kandev.rb"

bold()  { printf '\033[1m%s\033[0m' "$*"; }
green() { printf '\033[32m%s\033[0m' "$*"; }
red()   { printf '\033[31m%s\033[0m' "$*"; }

log()    { echo "  >> $*"; }
log_ok() { echo "  $(green "ok") $*"; }

die() {
  echo "$(red "Error:") $*" >&2
  exit 1
}

# -- Determine clone strategy: deploy key (SSH) or gh (HTTPS) -----------------

CLONE_METHOD="gh"
WORK_DIR="$(mktemp -d)"
TAP_DIR="$WORK_DIR/tap"
SSH_KEY_FILE=""
KNOWN_HOSTS_FILE=""

cleanup() {
  [[ -n "${SSH_KEY_FILE:-}" && -f "$SSH_KEY_FILE" ]] && rm -f "$SSH_KEY_FILE"
  [[ -n "${KNOWN_HOSTS_FILE:-}" && -f "$KNOWN_HOSTS_FILE" ]] && rm -f "$KNOWN_HOSTS_FILE"
  [[ -n "${WORK_DIR:-}" && -d "$WORK_DIR" ]] && rm -rf "$WORK_DIR"
}
trap cleanup EXIT

if [[ -n "${HOMEBREW_TAP_DEPLOY_KEY:-}" ]]; then
  CLONE_METHOD="ssh"
  # Materialize the deploy key + a custom GIT_SSH_COMMAND so it doesn't pollute ~/.ssh
  SSH_KEY_FILE="$(mktemp)"
  chmod 600 "$SSH_KEY_FILE"
  printf '%s\n' "$HOMEBREW_TAP_DEPLOY_KEY" > "$SSH_KEY_FILE"
  # Ensure trailing newline (some secret stores strip it; openssh requires it)
  if [[ "$(tail -c1 "$SSH_KEY_FILE")" != "" ]]; then
    echo "" >> "$SSH_KEY_FILE"
  fi

  # Pin GitHub's published SSH host keys so we don't trust whatever key the
  # remote presents. Source: https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/githubs-ssh-key-fingerprints
  KNOWN_HOSTS_FILE="$(mktemp)"
  chmod 600 "$KNOWN_HOSTS_FILE"
  cat > "$KNOWN_HOSTS_FILE" <<'EOF'
github.com ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOMqqnkVzrm0SdG6UOoqKLsabgH5C9okWi0dh2l9GKJl
github.com ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBEmKSENjQEezOmxkZMy7opKgwFB9nkt5YRrYMjNuG5N87uRgg6CLrbo5wAdT/y6v0mKV0U2w0WZ2YB/++Tpockg=
github.com ssh-rsa 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
EOF
  export GIT_SSH_COMMAND="ssh -i $SSH_KEY_FILE -o IdentitiesOnly=yes -o StrictHostKeyChecking=yes -o UserKnownHostsFile=$KNOWN_HOSTS_FILE -o LogLevel=ERROR"
  log "Using SSH deploy key for tap auth (pinned github.com host keys)"
fi

# -- Fetch sha256 values from GitHub release ----------------------------------

fetch_sha256() {
  local platform="$1"
  local sha_file="kandev-${platform}.tar.gz.sha256"
  local content
  # Download into WORK_DIR so the EXIT trap cleans it up automatically.
  content="$(gh release download "$TAG" --pattern "$sha_file" --dir "$WORK_DIR" 2>/dev/null && cat "$WORK_DIR/$sha_file")" || {
    die "Failed to download $sha_file from release $TAG."
  }
  # sha256 files contain: <hash>  <filename> — extract just the hash
  echo "$content" | awk '{print $1}'
}

log "Fetching sha256 values from GitHub release $TAG..."
SHA_MACOS_ARM64="$(fetch_sha256 macos-arm64)"
SHA_MACOS_X64="$(fetch_sha256 macos-x64)"
SHA_LINUX_ARM64="$(fetch_sha256 linux-arm64)"
SHA_LINUX_X64="$(fetch_sha256 linux-x64)"
log_ok "sha256 values retrieved"

# -- Clone tap repo -----------------------------------------------------------
# (WORK_DIR and TAP_DIR were created near the top so the EXIT trap covers them.)

log "Cloning $TAP_REPO..."
if [[ "$CLONE_METHOD" == "ssh" ]]; then
  git clone "git@github.com:${TAP_REPO}.git" "$TAP_DIR"
else
  gh repo clone "$TAP_REPO" "$TAP_DIR"
fi
log_ok "Tap cloned to $TAP_DIR"

# -- Generate formula ---------------------------------------------------------

FORMULA_PATH="$TAP_DIR/Formula/kandev.rb"
mkdir -p "$(dirname "$FORMULA_PATH")"

GITHUB_BASE="https://github.com/kdlbs/kandev/releases/download/${TAG}"

sed \
  -e "s|__VERSION__|$VERSION|g" \
  -e "s|__GITHUB_BASE__|$GITHUB_BASE|g" \
  -e "s|__SHA_MACOS_ARM64__|$SHA_MACOS_ARM64|g" \
  -e "s|__SHA_MACOS_X64__|$SHA_MACOS_X64|g" \
  -e "s|__SHA_LINUX_ARM64__|$SHA_LINUX_ARM64|g" \
  -e "s|__SHA_LINUX_X64__|$SHA_LINUX_X64|g" \
  "$FORMULA_TEMPLATE" > "$FORMULA_PATH"

log_ok "Formula written to Formula/kandev.rb"

# -- Commit and push (or open PR) ---------------------------------------------

cd "$TAP_DIR"
git config user.email "release-bot@kandev"
git config user.name "kandev release bot"

git add Formula/kandev.rb

if git diff --cached --quiet; then
  log "Formula unchanged — nothing to commit"
  exit 0
fi

git commit -m "kandev $VERSION"

# Deploy keys can push but cannot open PRs (PR creation requires user/app auth).
# So when using SSH (deploy key path) or HOMEBREW_TAP_PUSH=1, push directly.
if [[ "$CLONE_METHOD" == "ssh" || "$PUSH_DIRECT" == "1" ]]; then
  git push origin HEAD:main
  log_ok "Pushed directly to main in $TAP_REPO"
else
  BRANCH="update-kandev-$VERSION"
  git branch -m "$BRANCH"
  git push -u origin "$BRANCH"
  gh pr create \
    --repo "$TAP_REPO" \
    --title "kandev $VERSION" \
    --body "Updates formula to [kandev $VERSION](https://github.com/kdlbs/kandev/releases/tag/$TAG)." \
    --head "$BRANCH" \
    --base main
  log_ok "PR opened in $TAP_REPO"
fi

# WORK_DIR cleanup happens via the EXIT trap.
echo "$(green "$(bold "Homebrew tap updated to $VERSION!")")"