#!/usr/bin/env bash
# ==============================================================================
# remove.sh — Multi-Agent Mux (MAM) Orchestration Uninstaller
# ==============================================================================
# Safely removes MAM orchestration skills, virtual environment, and metadata.
# Leaves pre-existing user configurations and files untouched by reading
# the installation manifest (.mam/install_manifest.txt).
# ==============================================================================
set -euo pipefail

TARGET_DIR=""
FORCE=0
PURGE_ENV=0
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# Parse arguments
while [[ $# -gt 0 ]]; do
  case "$1" in
    -y|--yes|--force)
      FORCE=1
      shift
      ;;
    --purge-env)
      PURGE_ENV=1
      shift
      ;;
    *)
      TARGET_DIR="$1"
      shift
      ;;
  esac
done

if [ -z "$TARGET_DIR" ]; then
  if [ "$(basename "$SCRIPT_DIR")" = ".mam_deploy" ]; then
    TARGET_DIR="$(dirname "$SCRIPT_DIR")"
  else
    TARGET_DIR="$(pwd)"
  fi
else
  if [ "$(basename "$TARGET_DIR")" = ".mam_deploy" ]; then
    TARGET_DIR="$(dirname "$TARGET_DIR")"
  fi
fi

echo "===================================================================="
echo "⚡ Starting Multi-Agent Mux (MAM) Uninstallation"
echo "📂 Target Workspace: $TARGET_DIR"
echo "===================================================================="

if [ ! -d "$TARGET_DIR" ]; then
  echo "❌ Error: Target directory '$TARGET_DIR' does not exist." >&2
  exit 1
fi

cd "$TARGET_DIR"

GI_CREATED=0
if [ -f ".mam/install_state" ]; then
  GI_CREATED=$(grep '^gitignore_created=' .mam/install_state 2>/dev/null | cut -d= -f2 || echo 0)
fi

# 1. Non-interactive input safety guard (set -e read crash prevention)
if [ ! -t 0 ] && [ $FORCE -eq 0 ]; then
  echo "❌ Error: Non-interactive terminal detected. Please run with -y/--yes/--force." >&2
  exit 1
fi

# Check if there is anything to remove
MANIFEST_FILE=".mam/install_manifest.txt"
any_exist=0
manifest_files=()

# Load the install manifest if it exists
if [ -f "$MANIFEST_FILE" ]; then
  any_exist=1
  while IFS= read -r line; do
    if [ -n "$line" ]; then
      manifest_files+=("$line")
    fi
  done < "$MANIFEST_FILE"
else
  fallback_assets=(
    ".agents/skills/lib.sh"
    ".agents/skills/multi-agent-mux-create"
    ".agents/skills/multi-agent-mux-delegate-job"
    ".agents/skills/multi-agent-mux-loop"
    ".agents/skills/multi-agent-mux-monitor"
    ".agents/skills/multi-agent-mux-resume"
    ".agents/skills/multi-agent-mux-status"
    ".agents/skills/multi-agent-mux-stop"
    ".agents/hooks"
    ".agents/hooks.json"
    ".agents/MULTI_AGENT_RULES.md"
    ".agents/MULTI_AGENT_RULES.ko.md"
    ".agents/INSTALL.md"
    ".venv"
    ".mam"
    ".mam_deploy"
  )
  for asset in "${fallback_assets[@]}"; do
    if [ -e "$asset" ] || [ -h "$asset" ]; then
      any_exist=1
      break
    fi
  done
fi

if [ $any_exist -eq 0 ]; then
  echo "ℹ️  No MAM assets detected in '$TARGET_DIR'. Nothing to do."
  exit 0
fi

# Request confirmation if not forced
if [ $FORCE -eq 0 ]; then
  echo "⚠️  WARNING: This will permanently remove the MAM orchestration skills, "
  echo "   virtual environment (.venv), local metadata (.mam), and docs."
  
  if ! read -p "❓ Are you sure you want to proceed? [y/N]: " -r response; then
    response="n"
  fi
  if [[ ! "$response" =~ ^[yY](es)?$ ]]; then
    echo "❌ Uninstallation cancelled by user."
    exit 0
  fi
fi

delete_asset() {
  local asset="$1"
  if [ -e "$asset" ] || [ -h "$asset" ]; then
    echo "🗑️  Removing: $asset"
    rm -rf "$asset"
  fi
}

# Check for modified skills before deleting
TS=$(date -u +%Y%m%dT%H%M%SZ)
python3 - ".mam/asset_hashes.txt" "$TS" <<'PY' 2>/dev/null || true
import sys, os, hashlib, shutil

hash_db_path = sys.argv[1]
ts = sys.argv[2]

if not os.path.exists(hash_db_path):
    sys.exit(0)

modified = []
with open(hash_db_path, "r") as f:
    for line in f:
        parts = line.strip().split(None, 1)
        if len(parts) == 2:
            expected_hash, path = parts[0], parts[1]
            if os.path.exists(path):
                h = hashlib.sha256()
                with open(path, "rb") as pf:
                    while chunk := pf.read(65536):
                        h.update(chunk)
                if h.hexdigest() != expected_hash:
                    modified.append(path)

if modified:
    backup_dir = f".mam-skill-backup.{ts}"
    os.makedirs(backup_dir, exist_ok=True)
    for p in modified:
        dest = os.path.join(backup_dir, p)
        os.makedirs(os.path.dirname(dest), exist_ok=True)
        shutil.copy2(p, dest)
    print(f"💾 Preserved {len(modified)} modified skill file(s) under {backup_dir}")
PY

# 2. Uninstall files using the manifest if present
if [ ${#manifest_files[@]} -gt 0 ]; then
  echo "📜 Manifest found. Reversing installer-created files..."
  for f in ${manifest_files[@]+"${manifest_files[@]}"}; do
    if [ "$f" = ".env" ] || [ "$f" = ".mam.env" ] || [ "$f" = "remove.sh" ] || [ "$f" = ".mam_deploy/remove.sh" ]; then
      continue
    fi
    delete_asset "$f"
  done
else
  echo "⚠️  No manifest found. Deleting standard MAM assets..."
  for asset in ${fallback_assets[@]+"${fallback_assets[@]}"}; do
    case "$asset" in
      .venv|.mam|.mam_deploy) continue ;;   # handled explicitly further down
    esac
    delete_asset "$asset"
  done
fi

if [ -d ".agents" ]; then
  find .agents -depth -type d -exec rmdir {} + 2>/dev/null || true
fi

# Clean up .gitignore managed block (C8)
MAM_GI_START="# >>> MAM managed block (managed by install.sh — do not edit) >>>"
MAM_GI_END="# <<< MAM managed block <<<"

if [ -f .gitignore ]; then
  python3 - .gitignore "$MAM_GI_START" "$MAM_GI_END" "$GI_CREATED" <<'PY'
import sys, os

gi_path, start_marker, end_marker, gi_created = sys.argv[1], sys.argv[2], sys.argv[3], sys.argv[4] == "1"

if not os.path.exists(gi_path):
    sys.exit(0)

with open(gi_path, "r") as f:
    lines = f.readlines()

new_lines = []
in_block = False
block_found = False

for line in lines:
    if line.strip() == start_marker:
        in_block = True
        block_found = True
        continue
    if line.strip() == end_marker:
        in_block = False
        continue
    if not in_block:
        new_lines.append(line)

if block_found:
    content = "".join(new_lines).strip()
    if gi_created and not content:
        os.remove(gi_path)
    else:
        with open(gi_path, "w") as f:
            f.writelines(new_lines)
PY
fi

delete_asset ".venv"
delete_asset ".cache/multi-agent-mux-monitor"
rmdir ".cache" 2>/dev/null || true
delete_asset ".mam"

for env_name in ".mam.env" ".env"; do
  [ -f "$env_name" ] || continue
  
  env_created_by_mam=0
  for f in ${manifest_files[@]+"${manifest_files[@]}"}; do
    if [ "$f" = "$env_name" ]; then
      env_created_by_mam=1
      break
    fi
  done

  should_delete_env=0
  if [ $PURGE_ENV -eq 1 ]; then
    should_delete_env=1
  elif [ $env_created_by_mam -eq 1 ] && [ $FORCE -eq 0 ]; then
    if ! read -p "❓ MAM-created '$env_name' found. Delete it? (Saying No preserves it) [y/N]: " -r env_response; then
      env_response="n"
    fi
    if [[ "$env_response" =~ ^[yY](es)?$ ]]; then
      should_delete_env=1
    fi
  fi

  if [ $should_delete_env -eq 1 ]; then
    delete_asset "$env_name"
  else
    if [ $env_created_by_mam -eq 1 ]; then
      already_preserved=0
      for existing in "${env_name}.mam-backup" "${env_name}".mam-backup.*; do
        [ -f "$existing" ] || continue
        if cmp -s "$env_name" "$existing" 2>/dev/null; then
          already_preserved=1
          rm -f "$env_name"
          echo "ℹ️  '$env_name' is already preserved in $existing (no duplicate created)."
          break
        fi
      done

      if [ $already_preserved -eq 0 ]; then
        slot="${env_name}.mam-backup"
        if [ -e "$slot" ]; then
          slot="${env_name}.mam-backup.$(date +%Y%m%d%H%M%S)"
          n=1
          while [ -e "$slot" ]; do
            slot="${env_name}.mam-backup.$(date +%Y%m%d%H%M%S)-$n"
            n=$((n + 1))
          done
        fi
        mv "$env_name" "$slot"
        echo "💾 Backed up $env_name -> $slot"
      fi
    else
      echo "ℹ️  Preserving user-owned $env_name configuration."
    fi
  fi
done

# Remove uninstaller file(s)
for self in ".mam_deploy/remove.sh" "remove.sh"; do
  [ -f "$self" ] || continue
  in_manifest=0
  for f in ${manifest_files[@]+"${manifest_files[@]}"}; do
    if [ "$f" = "$self" ]; then
      in_manifest=1
      break
    fi
  done
  if [ $in_manifest -eq 1 ] || [ $FORCE -eq 1 ]; then
    echo "🗑️  Removing uninstaller: $self"
    rm -f "$self"
  fi
done

delete_asset ".mam_deploy/update.sh"
rmdir .mam_deploy 2>/dev/null || true

echo "===================================================================="
echo "🎉 Uninstallation complete!"
echo "===================================================================="