#!/usr/bin/env bash
# ============================================================
# BFG history cleanup for Veza monorepo
# ============================================================
# Goal: strip committed audio (.mp3/.wav), certs (.pem/.key/.crt),
# Go binaries, and AI session artefacts from git history, then
# compact .git from ~2.3 GB down to an expected <500 MB.
#
# WHEN TO RUN: after commits 98ee449f4 + 1f00fb762 (untrack debris
# + dev key regen) have been pushed to origin and reviewed.
#
# CHOICE: this script uses `git-filter-repo` (modern, fast, pure
# Python). BFG (Java) is supported as a fallback — set
# USE_BFG=1 to force it.
#
# ============================================================
# SAFETY MODEL
# ============================================================
# This script NEVER force-pushes by itself. It:
#   1. Verifies prereqs
#   2. Clones repo as bare mirror to /tmp/veza-bfg.git
#   3. Strips blobs > SIZE_THRESHOLD
#   4. Strips files matching FILE_PATTERNS
#   5. Runs aggressive gc
#   6. Prints size-before / size-after
#   7. Prints the exact force-push commands for YOU to run manually
#
# You verify the bare clone by hand before force-pushing. No surprises.
#
# ============================================================
# PREREQS
# ============================================================
#   git-filter-repo: pip install --user git-filter-repo
#     OR: https://github.com/newren/git-filter-repo
#   (fallback) BFG: https://rtyley.github.io/bfg-repo-cleaner/
#     Requires Java 8+. `brew install bfg` or download .jar
#
# ============================================================

set -euo pipefail

# ---------- CONFIG ----------
REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
BARE_CLONE="${BARE_CLONE:-/tmp/veza-bfg.git}"
SIZE_THRESHOLD="${SIZE_THRESHOLD:-5M}"
USE_BFG="${USE_BFG:-0}"

# Files to strip from ALL history (even if they're <SIZE_THRESHOLD).
# Match syntax differs: git-filter-repo uses glob, BFG uses bare name.
FILE_PATTERNS_FILTERREPO=(
  # Audio uploads (44 files, up to 26 MB each)
  "veza-backend-api/uploads/*.mp3"
  "veza-backend-api/uploads/*.wav"
  "veza-backend-api/uploads/*.flac"
  "veza-backend-api/uploads/*.ogg"
  "veza-backend-api/uploads/*.m4a"
  # TLS + JWT secrets (match at any depth)
  "**/*.pem"
  "**/*.key"
  "**/*.crt"
  # Go binaries historically committed
  "veza-backend-api/api"
  "veza-backend-api/main"
  "veza-backend-api/veza-api"
  "veza-backend-api/seed"
  "veza-backend-api/seed-v2"
  "veza-backend-api/server"
  "veza-backend-api/modern-server"
  "veza-backend-api/encrypt_oauth_tokens"
  "veza-backend-api/migrate_tool"
  # AI session artefacts
  "CLAUDE_CONTEXT.txt"
  "UI_CONTEXT_SUMMARY.md"
  # Root PNG blobs (all prefixes that were ever committed)
  "design-system-*.png"
  "forgot-password-*.png"
  "register-*.png"
  "reset-password-*.png"
  "settings-*.png"
  "storybook-*.png"
  "dashboard-*.png"
  "login-*.png"
  "audit-*.png"
  # Stale generated scripts
  "generate_page_fix_prompts.sh"
  # Apps/web dead reports
  "apps/web/AUDIT_ISSUES.json"
  "apps/web/audit_remediation.json"
  "apps/web/lint_comprehensive.json"
  "apps/web/storybook-roadmap.json"
  "apps/web/e2e-results.json"
)

# BFG equivalent list (bare filenames, no path)
FILE_PATTERNS_BFG=(
  "*.mp3" "*.wav" "*.flac" "*.ogg" "*.m4a"
  "*.pem" "*.key" "*.crt"
  "CLAUDE_CONTEXT.txt" "UI_CONTEXT_SUMMARY.md"
  "generate_page_fix_prompts.sh"
)

# ---------- HELPERS ----------
die() { echo "ERROR: $*" >&2; exit 1; }
section() { echo ""; echo "━━━ $* ━━━"; }

check_tool() {
  if command -v git-filter-repo >/dev/null 2>&1 && [[ "$USE_BFG" != "1" ]]; then
    TOOL="filter-repo"
  elif command -v bfg >/dev/null 2>&1; then
    TOOL="bfg"
  elif command -v java >/dev/null 2>&1 && [[ -f "${BFG_JAR:-/usr/local/lib/bfg.jar}" ]]; then
    TOOL="bfg-jar"
  else
    die "Install git-filter-repo (pip install --user git-filter-repo) or BFG (https://rtyley.github.io/bfg-repo-cleaner/)"
  fi
  echo "Using: $TOOL"
}

human_size() {
  du -sh "$1" 2>/dev/null | awk '{print $1}'
}

# ---------- SECTION 1: PREREQS ----------
section "1. Prereqs"
check_tool

[[ -d "$REPO_ROOT/.git" ]] || die "REPO_ROOT ($REPO_ROOT) is not a git repo"
cd "$REPO_ROOT"

# Refuse to run if working tree is dirty
if ! git diff-index --quiet HEAD --; then
  die "Working tree has uncommitted changes. Commit or stash first."
fi

CURRENT_BRANCH="$(git branch --show-current)"
echo "Current branch: $CURRENT_BRANCH"
echo "Current .git size: $(human_size .git)"

read -r -p "Proceed with bare mirror clone to $BARE_CLONE? [y/N] " ANSWER
[[ "$ANSWER" == "y" || "$ANSWER" == "Y" ]] || die "Aborted by user"

# ---------- SECTION 2: BARE MIRROR CLONE ----------
section "2. Bare mirror clone"
if [[ -e "$BARE_CLONE" ]]; then
  read -r -p "$BARE_CLONE already exists. Delete and recreate? [y/N] " ANSWER
  [[ "$ANSWER" == "y" || "$ANSWER" == "Y" ]] || die "Aborted"
  rm -rf "$BARE_CLONE"
fi

git clone --mirror "$REPO_ROOT" "$BARE_CLONE"
BEFORE_SIZE="$(human_size "$BARE_CLONE")"
echo "Bare clone size BEFORE: $BEFORE_SIZE"

# ---------- SECTION 3: STRIP ----------
section "3. Strip history"

cd "$BARE_CLONE"

if [[ "$TOOL" == "filter-repo" ]]; then
  # Strip blobs bigger than threshold
  git filter-repo --strip-blobs-bigger-than "$SIZE_THRESHOLD" --force

  # Strip specific path patterns
  PATH_ARGS=()
  for p in "${FILE_PATTERNS_FILTERREPO[@]}"; do
    if [[ "$p" == "!"* ]]; then continue; fi  # skip negations for now
    PATH_ARGS+=(--path-glob "$p")
  done
  # filter-repo uses --invert-paths to DELETE matched paths
  git filter-repo --invert-paths "${PATH_ARGS[@]}" --force

elif [[ "$TOOL" == "bfg" ]]; then
  # BFG: strip by size
  bfg --strip-blobs-bigger-than "$SIZE_THRESHOLD" --no-blob-protection .

  # BFG: strip by filename (no path — matches filename anywhere in history)
  for p in "${FILE_PATTERNS_BFG[@]}"; do
    bfg --delete-files "$p" --no-blob-protection .
  done

elif [[ "$TOOL" == "bfg-jar" ]]; then
  java -jar "${BFG_JAR}" --strip-blobs-bigger-than "$SIZE_THRESHOLD" --no-blob-protection .
  for p in "${FILE_PATTERNS_BFG[@]}"; do
    java -jar "${BFG_JAR}" --delete-files "$p" --no-blob-protection .
  done
fi

# ---------- SECTION 4: GC ----------
section "4. Aggressive gc"
git reflog expire --expire=now --all
git gc --prune=now --aggressive

AFTER_SIZE="$(human_size "$BARE_CLONE")"
echo ""
echo "━━━ RESULT ━━━"
echo "BEFORE: $BEFORE_SIZE"
echo "AFTER:  $AFTER_SIZE"
echo ""

# ---------- SECTION 5: NEXT STEPS ----------
section "5. Next steps (manual)"
cat <<MANUAL

The bare clone at $BARE_CLONE is ready. To finalize:

1. INSPECT — check a few refs to make sure history makes sense:
     cd $BARE_CLONE
     git log --oneline -20 main
     git log --oneline -5 chore/v1.0.7-cleanup
     git tag | head -20

2. VERIFY size reduction is reasonable:
     du -sh $BARE_CLONE

3. FORCE PUSH to origin (rewrites all refs + tags — all collaborators
   must re-clone):
     cd $BARE_CLONE
     git push --force --all origin
     git push --force --tags origin

4. RE-CLONE your working copy (the old one has pre-BFG history):
     cd "$(dirname "$REPO_ROOT")"
     mv veza veza-prebfg-backup
     git clone <origin-url> veza

   Or if you trust this machine's local blob state:
     cd $REPO_ROOT
     git reflog expire --expire=now --all
     git gc --prune=now --aggressive

5. REGENERATE local dev secrets that live outside git:
     ./scripts/generate-jwt-keys.sh
     ./scripts/generate-ssl-cert.sh

6. DELETE the bare clone once everything is verified stable:
     rm -rf $BARE_CLONE

MANUAL