package http

import (
	"context"
	"math"
	"net"
	"net/http"
	"strings"
	"time"

	"github.com/debridmediamanager.com/zurg/internal/config"
	cmap "github.com/orcaman/concurrent-map/v2"
	"go.uber.org/zap"
)

type HTTPClient struct {
	Client      *http.Client
	MaxRetries  int
	Backoff     func(attempt int) time.Duration
	ShouldRetry func(resp *http.Response, err error) int
	BearerToken string
	log         *zap.SugaredLogger
	config      config.ConfigInterface
	IPv6        cmap.ConcurrentMap[string, net.IP]
}

func (r *HTTPClient) Do(req *http.Request) (*http.Response, error) {
	req.Close = true
	if r.config != nil && strings.Contains(req.Host, "download.real-debrid.") {
		prefHost := r.config.GetRandomPreferredHost()
		if prefHost != "" {
			req.URL.Host = prefHost
		}
	}
	if r.BearerToken != "" {
		req.Header.Set("Authorization", "Bearer "+r.BearerToken)
	}

	if r.config.ShouldForceIPv6() {
		dialer := &net.Dialer{}
		transport := &http.Transport{
			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
				host, port, err := net.SplitHostPort(addr)
				if err != nil {
					return nil, err
				}
				if ipv6, ok := r.IPv6.Get(host); !ok {
					// Lookup IP address if not found in map
					ips, err := net.LookupIP(host)
					if err != nil {
						return nil, err
					}
					for _, ip := range ips {
						if ip.To4() == nil { // IPv6
							ipv6 = ip
							r.IPv6.Set(host, ipv6)
							break
						}
					}
					if ipv6 == nil { // No IPv6 address found, fallback to default
						addr = net.JoinHostPort(host, port)
					} else {
						addr = net.JoinHostPort(ipv6.String(), port)
					}
				} else if ipv6 != nil && host == req.URL.Hostname() {
					addr = net.JoinHostPort(ipv6.String(), port)
				}
				return dialer.DialContext(ctx, network, addr)
			},
		}
		r.Client.Transport = transport
	}

	var resp *http.Response
	var err error
	attempt := 0
	for {
		resp, err = r.Client.Do(req)
		if val := r.ShouldRetry(resp, err); val == -1 {
			return resp, err
		} else {
			if val == 0 {
				time.Sleep(8 * time.Second) // extra delay
			} else {
				attempt += val
				if attempt > r.MaxRetries {
					return resp, err
				}
				time.Sleep(r.Backoff(attempt))
			}
		}
	}
}

func NewHTTPClient(token string, maxRetries int, timeoutSecs int, cfg config.ConfigInterface, log *zap.SugaredLogger) *HTTPClient {
	return &HTTPClient{
		BearerToken: token,
		Client: &http.Client{
			Timeout: time.Duration(timeoutSecs) * time.Second,
		},
		MaxRetries: maxRetries,
		Backoff: func(attempt int) time.Duration {
			maxDuration := 60
			backoff := int(math.Pow(2, float64(attempt)))
			if backoff > maxDuration {
				backoff = maxDuration
			}
			return time.Duration(backoff) * time.Second
		},
		ShouldRetry: func(resp *http.Response, err error) int {
			if resp != nil {
				if resp.StatusCode == 429 || resp.StatusCode == 400 {
					return 0 // retry but don't increment attempt
				}
				return -1 // don't retry
			} else if err != nil {
				errStr := err.Error()
				if strings.Contains(errStr, "EOF") || strings.Contains(errStr, "connection reset") || strings.Contains(errStr, "no such host") {
					return 0 // retry but don't increment attempt
				} else {
					return 1
				}
			}
			return 1 // retry and increment attempt
		},
		log:    log,
		config: cfg,
		IPv6:   cmap.New[net.IP](),
	}
}