#!/usr/bin/env bash
set -euo pipefail

GHCR_PAT="$1"
NEW_TAG="${2:-latest}"
TAG_FILE="/var/lib/polyweather/.current_tag"
COMPOSE_DIR="/root/PolyWeather"
LOCK_FILE="${POLYWEATHER_DEPLOY_LOCK_FILE:-/var/lock/polyweather-deploy.lock}"

mkdir -p "$(dirname "$LOCK_FILE")"
exec 9>"$LOCK_FILE"
if ! flock -n 9; then
    echo "❌ Another PolyWeather deploy is already running"
    exit 1
fi

echo "$GHCR_PAT" | docker login ghcr.io -u yangyuan-zhen --password-stdin

cd "$COMPOSE_DIR"
git fetch origin main && git reset --hard origin/main

PREVIOUS_TAG=""
if [ -f "$TAG_FILE" ]; then
    PREVIOUS_TAG=$(cat "$TAG_FILE")
    echo "Previous tag: $PREVIOUS_TAG"
fi

rollback_to_previous() {
    if [ -n "$PREVIOUS_TAG" ]; then
        echo "Rolling back to $PREVIOUS_TAG..."
        export IMAGE_TAG="$PREVIOUS_TAG"
        docker compose pull
        docker compose up -d
        echo "✅ Rolled back to $PREVIOUS_TAG"
    else
        echo "⚠️  No previous tag to rollback to"
    fi
}

export IMAGE_TAG="$NEW_TAG"
pull_ok=0
for pull_attempt in $(seq 1 6); do
    docker compose pull && pull_ok=1 && break
    echo "Image pull failed or tag not ready, retry ${pull_attempt}/6..."
    sleep 10
done
if [ "$pull_ok" != "1" ]; then
    echo "❌ Image pull failed after retries"
    exit 1
fi

smoke_check() {
    local name="$1"
    local url="$2"
    local timeout="$3"
    local attempts="${4:-6}"
    local delay="${5:-5}"

    for i in $(seq 1 "$attempts"); do
        if curl -fsSo /dev/null --max-time "$timeout" "$url"; then
            echo "✅ $name"
            return 0
        fi
        if [ "$i" != "$attempts" ]; then
            echo "   $name retry $i/$attempts..."
            sleep "$delay"
        fi
    done

    echo "❌ $name"
    return 1
}

wait_for_local_service() {
    local name="$1"
    local url="$2"
    local timeout="${3:-5}"
    local attempts="${4:-30}"
    local delay="${5:-2}"

    for i in $(seq 1 "$attempts"); do
        if curl -fsSo /dev/null --max-time "$timeout" "$url"; then
            echo "✅ $name ready after attempt $i/$attempts"
            return 0
        fi
        if [ "$i" != "$attempts" ]; then
            echo "   $name warming $i/$attempts..."
            sleep "$delay"
        fi
    done

    echo "❌ $name did not become ready"
    return 1
}

warm_public_route() {
    local name="$1"
    local url="$2"
    local timeout="${3:-15}"
    local attempts="${4:-3}"
    local delay="${5:-2}"

    for i in $(seq 1 "$attempts"); do
        if curl -fsSo /dev/null --max-time "$timeout" "$url"; then
            echo "✅ warmed $name"
            return 0
        fi
        if [ "$i" != "$attempts" ]; then
            echo "   warm $name retry $i/$attempts..."
            sleep "$delay"
        fi
    done

    echo "⚠️  warm $name failed"
    return 0
}

echo "Updating Redis dependency..."
docker compose up -d polyweather_redis

echo "Updating backend services..."
docker compose up -d --no-deps polyweather_web polyweather

echo "Waiting for backend..."
wait_for_local_service "backend healthz" "http://127.0.0.1:8000/healthz" 5 30 5 || FAILED_BACKEND=1
FAILED_BACKEND="${FAILED_BACKEND:-0}"
if [ "$FAILED_BACKEND" = "1" ]; then
    echo "❌ Backend did not become healthy"
    rollback_to_previous
    exit 1
fi

echo "Updating frontend..."
docker compose up -d --no-deps polyweather_frontend

echo "Waiting for frontend..."
wait_for_local_service "frontend root" "http://127.0.0.1:3001/" 5 40 2 || FAILED_FRONTEND=1
wait_for_local_service "frontend terminal" "http://127.0.0.1:3001/terminal" 10 20 2 || FAILED_FRONTEND=1
FAILED_FRONTEND="${FAILED_FRONTEND:-0}"
if [ "$FAILED_FRONTEND" = "1" ]; then
    echo "❌ Frontend did not become healthy"
    rollback_to_previous
    exit 1
fi

warm_public_route "terminal" "https://polyweather.top/terminal" 20 4 3
warm_public_route "auth snapshot" "https://polyweather.top/api/auth/me?prefer_snapshot=1" 10 3 2
warm_public_route "cities" "https://polyweather.top/api/cities" 20 3 2

FAILED=0
smoke_check "healthz" "https://api.polyweather.top/healthz" 15 3 5 || FAILED=1
smoke_check "cities" "https://api.polyweather.top/api/cities" 15 8 5 || FAILED=1
smoke_check "frontend" "https://www.polyweather.top/" 15 3 5 || FAILED=1

if [ "$FAILED" = "1" ]; then
    echo "❌ Smoke tests failed. Rolling back..."
    rollback_to_previous
    exit 1
fi

mkdir -p "$(dirname "$TAG_FILE")"
echo "$NEW_TAG" > "$TAG_FILE"
docker image prune -af
echo "✅ Deployed $NEW_TAG"