#!/usr/bin/env bash
# Confidence Engine — Production Deployment Script
#
# Executes on CT 112 at /opt/confidence-engine.
# Input: $1 = exact commit SHA (validated)
#
# Environment:
#   DEPLOY_DIR        - target repository path (defaults /opt/confidence-engine)
#   HEALTH_URL        - health check endpoint (defaults http://127.0.0.1:3000/api/health)
#
# Reads deploy.env from $DEPLOY_DIR/deploy.env for runtime values.

set -euo pipefail

# ── Parameters ──────────────────────────────────────────────────────

DEPLOY_SHA="${1:?Error: missing commit SHA argument}"
DEPLOY_DIR="${DEPLOY_DIR:-/opt/confidence-engine}"
HEALTH_URL="${HEALTH_URL:-http://127.0.0.1:3000/api/health}"

# ── Validation ──────────────────────────────────────────────────────

if [[ ${#DEPLOY_SHA} -lt 7 ]]; then
  echo "ERROR: SHA must be at least 7 hex characters."
  exit 1
fi

if ! echo "$DEPLOY_SHA" | grep -qE '^[0-9a-fA-F]+$'; then
  echo "ERROR: SHA contains non-hex characters."
  exit 1
fi

echo "Deploying SHA: $DEPLOY_SHA"

cd "$DEPLOY_DIR" || { echo "ERROR: Cannot cd to $DEPLOY_DIR"; exit 1; }

# ── Safety checks ───────────────────────────────────────────────────

# deploy.env must exist on the host (not tracked by Git)
if [[ ! -f deploy.env ]]; then
  echo "DEPLOYMENT BLOCKED - deploy.env not found at deploy.env"
  exit 1
fi

# Check for uncommitted changes that would block safe checkout
if ! git diff-index --quiet HEAD -- 2>/dev/null; then
  echo "DEPLOYMENT BLOCKED - target working tree has uncommitted changes"
  exit 1
fi

if [[ -n "$(git ls-files --others --exclude-standard)" ]]; then
  echo "DEPLOYMENT BLOCKED - target working tree has untracked files"
  exit 1
fi

# ── Fetch and verify SHA ────────────────────────────────────────────

echo "Fetching latest refs from origin..."
git fetch origin >/dev/null 2>&1 || {
  echo "ERROR: git fetch origin failed."
  exit 1
}

if ! git rev-parse --verify "$DEPLOY_SHA" >/dev/null 2>&1; then
  echo "ERROR: SHA $DEPLOY_SHA not found in repository after fetch."
  exit 1
fi

# ── Detached checkout (never modifies working tree or remote) ───────

echo "Checking out exactly $DEPLOY_SHA..."
git checkout --detach "$DEPLOY_SHA" >/dev/null 2>&1 || {
  echo "ERROR: Could not checkout SHA $DEPLOY_SHA."
  exit 1
}

# Verify the detached HEAD matches our deploy SHA
CURRENT_SHA="$(git rev-parse HEAD)"
if [[ "${CURRENT_SHA%"${CURRENT_SHA#?}"}" != "${DEPLOY_SHA%"${DEPLOY_SHA#?}"}" ]] || \
   [[ "$CURRENT_SHA" != "$DEPLOY_SHA" && "${CURRENT_SHA:0:7}" != "${DEPLOY_SHA:0:7}" ]]; then
  echo "ERROR: Checked out SHA $CURRENT_SHA does not match requested $DEPLOY_SHA."
  exit 1
fi

# ── Load runtime environment ────────────────────────────────────────

if [[ -f deploy.env ]]; then
  set -a
  # shellcheck disable=SC1091
  source deploy.env
  set +a
else
  echo "ERROR: deploy.env not found at $DEPLOY_DIR/deploy.env"
  exit 1
fi

# ── Build Docker image ──────────────────────────────────────────────

IMAGE_TAG="confidence-engine:${DEPLOY_SHA}"

echo "Building Docker image ${IMAGE_TAG}..."
docker build \
  --build-arg NEXT_PUBLIC_SUPABASE_URL="${NEXT_PUBLIC_SUPABASE_URL}" \
  --build-arg NEXT_PUBLIC_SUPABASE_ANON_KEY="${NEXT_PUBLIC_SUPABASE_ANON_KEY}" \
  -t "${IMAGE_TAG}" \
  .

echo "Image ${IMAGE_TAG} built successfully."

# ── Container replacement ───────────────────────────────────────────

CONTAINER_NAME="confidence-engine"

# Record previous image before replacing container
PREV_IMAGE=""
if docker ps -a --format '{{.Names}}' | grep -qx "$CONTAINER_NAME"; then
  PREV_IMAGE="$(docker inspect --format='{{.Config.Image}}' "$CONTAINER_NAME" 2>/dev/null || echo "")"
fi

echo "Stopping existing container (if running)..."
docker stop "$CONTAINER_NAME" >/dev/null 2>&1 || true
docker rm -f "$CONTAINER_NAME" >/dev/null 2>&1 || true

echo "Starting new container from ${IMAGE_TAG}..."
docker run -d \
  --name "$CONTAINER_NAME" \
  --restart unless-stopped \
  -p 3000:3000 \
  -e OLLAMA_BASE_URL="${OLLAMA_BASE_URL}" \
  -e OLLAMA_MODEL="${OLLAMA_MODEL}" \
  "${IMAGE_TAG}"

echo "Container $CONTAINER_NAME started."

# ── Health check polling ────────────────────────────────────────────

HEALTH_CHECK_TIMEOUT=60
HEALTH_CHECK_INTERVAL=3
ELAPSED=0

echo "Waiting for health check at ${HEALTH_URL}..."

while [[ $ELAPSED -lt $HEALTH_CHECK_TIMEOUT ]]; do
  if curl -sf "$HEALTH_URL" | grep -q '"healthy"[[:space:]]*:[[:space:]]*true'; then
    echo ""
    echo "============================================="
    echo "DEPLOYMENT SUCCEEDED"
    echo "Deployed SHA: $DEPLOY_SHA"
    echo "Current image: $(docker inspect --format='{{.Config.Image}}' "$CONTAINER_NAME" 2>/dev/null || echo 'unknown')"
    echo "============================================="
    exit 0
  fi

  sleep "$HEALTH_CHECK_INTERVAL"
  ELAPSED=$((ELAPSED + HEALTH_CHECK_INTERVAL))
done

echo ""
echo "============================================="
echo "DEPLOYMENT FAILED - Health check timed out after ${HEALTH_CHECK_TIMEOUT}s"
echo "============================================="

# ── Rollback (one attempt) ──────────────────────────────────────────

if [[ -n "$PREV_IMAGE" ]]; then
  echo ""
  echo "Attempting rollback to previous image: $PREV_IMAGE"
  docker stop "$CONTAINER_NAME" >/dev/null 2>&1 || true
  docker rm -f "$CONTAINER_NAME" >/dev/null 2>&1 || true

  docker run -d \
    --name "$CONTAINER_NAME" \
    --restart unless-stopped \
    -p 3000:3000 \
    -e OLLAMA_BASE_URL="${OLLAMA_BASE_URL}" \
    -e OLLAMA_MODEL="${OLLAMA_MODEL}" \
    "$PREV_IMAGE"

  if [[ $? -eq 0 ]]; then
    echo "DEPLOYMENT FAILED - ROLLED BACK to $PREV_IMAGE"
  else
    echo "DEPLOYMENT FAILED - ROLLBACK ALSO FAILED"
  fi
else
  echo "No previous image available for rollback."
fi

echo "DEPLOYMENT FAILED - MANUAL RECOVERY REQUIRED"
exit 1