package app

import (
	"context"
	"fmt"
	"strconv"
	"strings"
	"time"

	"github.com/redis/go-redis/v9"
	"github.com/gochat/gochat/internal/config"
	"github.com/gochat/gochat/pkg/logger"
)

// NewRedisClient creates a Redis client for caching, Pub/Sub, and sessions.
// Reference: Chatwoot config/cable.yml Redis adapter configuration
func NewRedisClient(cfg *config.RedisConfig) (*redis.Client, error) {
	opts, err := parseRedisURL(cfg.URL)
	if err != nil {
		return nil, fmt.Errorf("failed to parse Redis URL: %w", err)
	}

	if cfg.Password != "" {
		opts.Password = cfg.Password
	}
	opts.PoolSize = 10

	client := redis.NewClient(opts)

	// Verify connection
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	if err := client.Ping(ctx).Err(); err != nil {
		return nil, fmt.Errorf("failed to connect to Redis: %w", err)
	}

	logger.L().Infof("Connected to Redis: %s (pool=%d)", cfg.URL, 10)

	return client, nil
}

// parseRedisURL parses a Redis URL into redis.Options.
// Handles both "redis://host:port" and "redis://user:password@host:port/db" formats.
func parseRedisURL(urlStr string) (*redis.Options, error) {
	opts, err := redis.ParseURL(urlStr)
	if err != nil {
		// Fallback: simple host:port parsing
		parts := strings.Split(strings.TrimPrefix(urlStr, "redis://"), ":")
		if len(parts) < 2 {
			return nil, fmt.Errorf("invalid Redis URL format: %s", urlStr)
		}
		port, err := strconv.Atoi(parts[1])
		if err != nil {
			return nil, fmt.Errorf("invalid Redis port: %s", parts[1])
		}
		opts = &redis.Options{
			Addr: fmt.Sprintf("%s:%d", parts[0], port),
		}
	}
	return opts, nil
}