package stripe

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"regexp"
	"strings"
	"time"

	"gpt-plus/config"
)

// aimizyResponse represents the JSON response from the Aimizy API.
type aimizyResponse struct {
	Success           bool   `json:"success"`
	CheckoutSessionID string `json:"checkout_session_id"`
	URL               string `json:"url"`
	PublishableKey    string `json:"publishable_key"`
	Error             string `json:"error"`
	Message           string `json:"message"`
}

var csLiveRe = regexp.MustCompile(`cs_live_[A-Za-z0-9]+`)

// CreateCheckoutViaAimizy uses the Aimizy API to generate a $0 checkout session.
// This is an alternative to calling ChatGPT's /backend-api/payments/checkout directly.
// Returns a CheckoutResult compatible with the normal Stripe flow.
func CreateCheckoutViaAimizy(aimizy config.AimizyConfig, accessToken, country, currency, planName, promoCampaignID string, seatQuantity int) (*CheckoutResult, error) {
	payload := map[string]interface{}{
		"access_token":                accessToken,
		"check_card_proxy":            false,
		"country":                     country,
		"currency":                    currency,
		"is_coupon_from_query_param":  true,
		"is_short_link":               true,
		"plan_name":                   planName,
		"price_interval":              "month",
		"promo_campaign_id":           promoCampaignID,
	}

	// Team plan needs seat_quantity
	if seatQuantity > 0 {
		payload["seat_quantity"] = seatQuantity
	}

	jsonBody, err := json.Marshal(payload)
	if err != nil {
		return nil, fmt.Errorf("marshal aimizy payload: %w", err)
	}

	apiURL := aimizy.BaseURL + "/api/public/generate-payment-link"

	var resp *http.Response
	var respBody []byte
	directClient := &http.Client{Timeout: 30 * time.Second}

	for try := 1; try <= 3; try++ {
		req, err := http.NewRequest("POST", apiURL, strings.NewReader(string(jsonBody)))
		if err != nil {
			return nil, fmt.Errorf("build aimizy request: %w", err)
		}
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("Accept", "application/json")
		req.Header.Set("Origin", aimizy.BaseURL)
		req.Header.Set("Referer", aimizy.BaseURL+"/pay")
		req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36")

		resp, err = directClient.Do(req)
		if err != nil {
			log.Printf("[aimizy] attempt %d/3: request error: %v", try, err)
			if try < 3 {
				time.Sleep(3 * time.Second)
				continue
			}
			return nil, fmt.Errorf("aimizy request failed after 3 attempts: %w", err)
		}

		respBody, err = io.ReadAll(resp.Body)
		resp.Body.Close()
		if err != nil {
			return nil, fmt.Errorf("read aimizy response: %w", err)
		}

		// Log full response headers and body
		log.Printf("[aimizy] attempt %d/3: status=%d", try, resp.StatusCode)
		for k, vs := range resp.Header {
			for _, v := range vs {
				log.Printf("[aimizy] response header: %s: %s", k, v)
			}
		}
		log.Printf("[aimizy] response body: %s", string(respBody))

		if resp.StatusCode == 200 {
			break
		}
		log.Printf("[aimizy] attempt %d/3: status %d, retrying...", try, resp.StatusCode)
		if try < 3 {
			time.Sleep(3 * time.Second)
		}
	}

	if resp == nil || resp.StatusCode != 200 {
		statusCode := 0
		if resp != nil {
			statusCode = resp.StatusCode
		}
		return nil, fmt.Errorf("aimizy failed: status %d, body: %s", statusCode, string(respBody))
	}

	var result aimizyResponse
	if err := json.Unmarshal(respBody, &result); err != nil {
		return nil, fmt.Errorf("parse aimizy response: %w (body: %s)", err, string(respBody))
	}

	if !result.Success {
		return nil, fmt.Errorf("aimizy returned success=false: %s", string(respBody))
	}

	// Extract checkout_session_id
	csID := result.CheckoutSessionID
	if csID == "" && result.URL != "" {
		// Fallback: extract from URL
		if m := csLiveRe.FindString(result.URL); m != "" {
			csID = m
		}
	}
	if csID == "" {
		return nil, fmt.Errorf("aimizy returned no checkout_session_id: %s", string(respBody))
	}

	// Build compatible CheckoutResult
	cr := &CheckoutResult{
		CheckoutSessionID: csID,
		ProcessorEntity:   "openai_llc",
		PublishableKey:     result.PublishableKey,
	}

	// If publishable_key not in aimizy response, use the known production key
	if cr.PublishableKey == "" {
		cr.PublishableKey = "pk_live_51HOrSwC6h1nxGoI3lTAgRjYVrz4dU3fVOabyCcKR3pbEJguCVAlqCxdxCUvoRh1XWwRacViovU3kLKvpkjh7IqkW00iXQsjo3n"
	}

	log.Printf("[aimizy] checkout session created: %s (key=%s)", cr.CheckoutSessionID, cr.PublishableKey[:20]+"...")

	return cr, nil
}