#!/bin/bash
# ─────────────────────────────────────────────────────────────────────────────
# LMS — Docker Compose Build & Run Script
# Usage:
#   ./build.sh              # build + start (production)
#   ./build.sh --no-cache   # force full rebuild (no Docker layer cache)
#   ./build.sh --down       # stop and remove containers
#   ./build.sh --restart    # stop, rebuild, and start
#   ./build.sh --logs       # tail logs after starting
# ─────────────────────────────────────────────────────────────────────────────

set -euo pipefail

# ── Colour helpers ────────────────────────────────────────────────────────────
RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'
CYAN='\033[0;36m'; BOLD='\033[1m'; RESET='\033[0m'
ok()   { echo -e "${GREEN}✔${RESET}  $*"; }
info() { echo -e "${CYAN}▶${RESET}  $*"; }
warn() { echo -e "${YELLOW}⚠${RESET}  $*"; }
fail() { echo -e "${RED}✘${RESET}  $*" >&2; exit 1; }
step() { echo -e "\n${BOLD}${CYAN}══ $* ══${RESET}"; }

# ── Parse flags ───────────────────────────────────────────────────────────────
NO_CACHE=false
DO_DOWN=false
DO_RESTART=false
DO_LOGS=false

for arg in "$@"; do
  case $arg in
    --no-cache) NO_CACHE=true ;;
    --down)     DO_DOWN=true ;;
    --restart)  DO_RESTART=true ;;
    --logs)     DO_LOGS=true ;;
    --help|-h)
      sed -n '/^# Usage:/,/^# ─/p' "$0" | grep '^#' | sed 's/^# \?//'
      exit 0 ;;
    *) fail "Unknown option: $arg" ;;
  esac
done

# ── Change to script directory ────────────────────────────────────────────────
cd "$(dirname "$0")"

# ── Helper: check required commands ──────────────────────────────────────────
require_cmd() {
  command -v "$1" &>/dev/null || fail "'$1' is not installed or not in PATH."
}
require_cmd docker
require_cmd docker compose 2>/dev/null || {
  # Older Docker installs use "docker-compose" instead of "docker compose"
  require_cmd docker-compose
  # Shim so the rest of the script uses the right command
  docker() {
    if [ "$1" = "compose" ]; then shift; docker-compose "$@"; else command docker "$@"; fi
  }
  export -f docker
}

# ─────────────────────────────────────────────────────────────────────────────
# --down: stop and remove containers
# ─────────────────────────────────────────────────────────────────────────────
if $DO_DOWN; then
  step "Stopping & removing containers"
  docker compose down --remove-orphans
  ok "All containers stopped."
  exit 0
fi

# ─────────────────────────────────────────────────────────────────────────────
# Validate .env
# ─────────────────────────────────────────────────────────────────────────────
step "Checking .env"

if [ ! -f .env ]; then
  warn ".env not found — copying from .env.example"
  if [ ! -f .env.example ]; then
    fail ".env.example not found either. Cannot continue."
  fi
  cp .env.example .env
  echo ""
  warn "Please edit .env and set POSTGRES_PASSWORD and JWT_SECRET_KEY, then re-run this script."
  exit 1
fi

source .env

ERRORS=0
check_var() {
  local name=$1 val=${!1:-} placeholder=${2:-""}
  if [ -z "$val" ] || { [ -n "$placeholder" ] && [ "$val" = "$placeholder" ]; }; then
    warn "Missing or placeholder value for ${BOLD}${name}${RESET} in .env"
    ERRORS=$((ERRORS+1))
  fi
}

check_var POSTGRES_PASSWORD "change_me_strong_password"
check_var JWT_SECRET_KEY    "change_me_generate_with_secrets_token_hex_32"

if [ $ERRORS -gt 0 ]; then
  echo ""
  echo -e "  ${YELLOW}Tip — generate a JWT secret:${RESET}"
  echo "    python3 -c \"import secrets; print(secrets.token_hex(32))\""
  echo ""
  fail "Fix the above values in .env and re-run."
fi

ok ".env looks good"

# ─────────────────────────────────────────────────────────────────────────────
# --restart: tear down first
# ─────────────────────────────────────────────────────────────────────────────
if $DO_RESTART; then
  step "Stopping existing containers"
  docker compose down --remove-orphans
  ok "Stopped."
fi

# ─────────────────────────────────────────────────────────────────────────────
# Build images
# ─────────────────────────────────────────────────────────────────────────────
step "Building Docker images"

BUILD_ARGS=""
$NO_CACHE && BUILD_ARGS="--no-cache" && warn "Building without layer cache (--no-cache)"

# shellcheck disable=SC2086
docker compose build $BUILD_ARGS

ok "Images built successfully"

# ─────────────────────────────────────────────────────────────────────────────
# Start stack
# ─────────────────────────────────────────────────────────────────────────────
step "Starting services"
docker compose up -d --remove-orphans

# ─────────────────────────────────────────────────────────────────────────────
# Wait for backend health
# ─────────────────────────────────────────────────────────────────────────────
step "Waiting for backend to become healthy"

MAX_WAIT=60
ELAPSED=0
INTERVAL=3
printf "   "
while true; do
  STATUS=$(docker compose ps --format json backend 2>/dev/null \
    | python3 -c "import sys,json; d=json.load(sys.stdin); print(d.get('Health','') or d.get('State',''))" 2>/dev/null || echo "")
  case "$STATUS" in
    healthy)  echo ""; ok "Backend is healthy"; break ;;
    running)  printf "."; sleep $INTERVAL; ELAPSED=$((ELAPSED+INTERVAL)) ;;
    *)        printf "."; sleep $INTERVAL; ELAPSED=$((ELAPSED+INTERVAL)) ;;
  esac
  if [ $ELAPSED -ge $MAX_WAIT ]; then
    echo ""
    warn "Timed out waiting for backend health check — checking logs:"
    docker compose logs --tail=20 backend
    break
  fi
done

# ─────────────────────────────────────────────────────────────────────────────
# Summary
# ─────────────────────────────────────────────────────────────────────────────
PORT="${FRONTEND_PORT:-3011}"
echo ""
echo -e "${BOLD}${GREEN}══════════════════════════════════════════${RESET}"
echo -e "${BOLD}${GREEN}  ✅  LMS is up!${RESET}"
echo -e "${BOLD}${GREEN}══════════════════════════════════════════${RESET}"
echo -e "  ${BOLD}App URL  :${RESET}  http://localhost:${PORT}"
echo -e "  ${BOLD}Backend  :${RESET}  http://localhost:${PORT}/api/docs  (via proxy)"
echo ""
docker compose ps
echo ""

# ─────────────────────────────────────────────────────────────────────────────
# Tail logs if requested
# ─────────────────────────────────────────────────────────────────────────────
if $DO_LOGS; then
  step "Tailing logs (Ctrl+C to stop)"
  docker compose logs -f
fi