package identity

import (
	"context"
	"errors"
	"fmt"
	"log"
	"net/http"
	"time"
)

// VerificationProvider defines the interface for all identity verification providers
type VerificationProvider interface {
	// VerifyCitizenship checks if a user is a citizen of the supported country
	VerifyCitizenship(ctx context.Context, userData map[string]string) (bool, error)

	// VerifyEligibility checks if a user is eligible to participate (e.g., voting rights)
	VerifyEligibility(ctx context.Context, userData map[string]string) (bool, error)

	// GetCountry returns the country code this provider supports
	GetCountry() string
}

// USVerificationProvider implements verification for US citizens using Privado ID
type USVerificationProvider struct {
	privadoClient *PrivadoClient
}

// NewUSVerificationProvider creates a new USVerificationProvider with Privado ID integration
func NewUSVerificationProvider(apiKey string, apiURL string) *USVerificationProvider {
	return &USVerificationProvider{
		privadoClient: NewPrivadoClient(apiKey, apiURL),
	}
}

// VerifyCitizenship for US citizens using Privado ID's ZKP system
func (p *USVerificationProvider) VerifyCitizenship(ctx context.Context, userData map[string]string) (bool, error) {
	// Extract ZKP token
	zkpToken, exists := userData["zkpProof"]
	if !exists {
		return false, errors.New("zkpProof is required for US citizenship verification")
	}

	// Verify the ZKP token with Privado ID
	verified, err := p.privadoClient.VerifyZKP(ctx, zkpToken)
	if err != nil {
		log.Printf("Privado ID verification failed: %v", err)
		return false, fmt.Errorf("verification service error: %v", err)
	}

	return verified, nil
}

// VerifyEligibility for US citizens based on self-attestation with legal disclaimer
func (p *USVerificationProvider) VerifyEligibility(ctx context.Context, userData map[string]string) (bool, error) {
	// Check if the user has self-attested to being eligible
	selfAttested, exists := userData["selfAttestedEligible"]
	if !exists {
		return false, errors.New("selfAttestedEligible field is required for eligibility verification")
	}

	// Check if user has acknowledged the legal disclaimer
	disclaimer, exists := userData["legalDisclaimerAcknowledged"]
	if !exists || disclaimer != "true" {
		return false, errors.New("user must acknowledge the legal disclaimer for eligibility verification")
	}

	return selfAttested == "true", nil
}

// GetCountry returns the country code for US
func (p *USVerificationProvider) GetCountry() string {
	return "US"
}

// CanadaVerificationProvider implements verification for Canadian citizens
type CanadaVerificationProvider struct {
	privadoClient *PrivadoClient
}

// NewCanadaVerificationProvider creates a new CanadaVerificationProvider with Privado ID integration
func NewCanadaVerificationProvider(apiKey string, apiURL string) *CanadaVerificationProvider {
	return &CanadaVerificationProvider{
		privadoClient: NewPrivadoClient(apiKey, apiURL),
	}
}

// VerifyCitizenship for Canadian citizens using Privado ID
func (p *CanadaVerificationProvider) VerifyCitizenship(ctx context.Context, userData map[string]string) (bool, error) {
	// Extract ZKP token
	zkpToken, exists := userData["zkpProof"]
	if !exists {
		return false, errors.New("zkpProof is required for Canada citizenship verification")
	}

	// Verify the ZKP token with Privado ID
	verified, err := p.privadoClient.VerifyZKP(ctx, zkpToken)
	if err != nil {
		log.Printf("Privado ID verification failed: %v", err)
		return false, fmt.Errorf("verification service error: %v", err)
	}

	return verified, nil
}

// VerifyEligibility for Canadian citizens based on self-attestation
func (p *CanadaVerificationProvider) VerifyEligibility(ctx context.Context, userData map[string]string) (bool, error) {
	// Check if the user has self-attested to being eligible
	selfAttested, exists := userData["selfAttestedEligible"]
	if !exists {
		return false, errors.New("selfAttestedEligible field is required for eligibility verification")
	}

	// Check if user has acknowledged the legal disclaimer
	disclaimer, exists := userData["legalDisclaimerAcknowledged"]
	if !exists || disclaimer != "true" {
		return false, errors.New("user must acknowledge the legal disclaimer for eligibility verification")
	}

	return selfAttested == "true", nil
}

// GetCountry returns the country code for Canada
func (p *CanadaVerificationProvider) GetCountry() string {
	return "CA"
}

// PlaceholderVerificationProvider is a generic provider for countries without specific implementation
type PlaceholderVerificationProvider struct {
	country string
}

// NewPlaceholderVerificationProvider creates a new placeholder provider for the specified country
func NewPlaceholderVerificationProvider(country string) *PlaceholderVerificationProvider {
	return &PlaceholderVerificationProvider{
		country: country,
	}
}

// VerifyCitizenship for placeholder provider always returns true
func (p *PlaceholderVerificationProvider) VerifyCitizenship(ctx context.Context, userData map[string]string) (bool, error) {
	log.Printf("Using placeholder verification for %s citizenship", p.country)
	return true, nil
}

// VerifyEligibility for placeholder provider always returns true
func (p *PlaceholderVerificationProvider) VerifyEligibility(ctx context.Context, userData map[string]string) (bool, error) {
	log.Printf("Using placeholder verification for %s eligibility", p.country)
	return true, nil
}

// GetCountry returns the country code this provider supports
func (p *PlaceholderVerificationProvider) GetCountry() string {
	return p.country
}

// GetVerificationProvider returns the appropriate provider based on country code
func GetVerificationProvider(country string) VerificationProvider {
	// Get Privado API key and URL from environment
	privadoAPIKey := getPrivadoAPIKey()
	privadoAPIURL := getPrivadoAPIURL()

	// Always normalize country code to uppercase
	switch country {
	case "US":
		return NewUSVerificationProvider(privadoAPIKey, privadoAPIURL)
	case "CA":
		return NewCanadaVerificationProvider(privadoAPIKey, privadoAPIURL)
	default:
		return NewPlaceholderVerificationProvider(country)
	}
}

// Helper functions to get environment variables
func getPrivadoAPIKey() string {
	// In a real implementation, this would get the API key from environment variables
	return "privado-api-key"
}

func getPrivadoAPIURL() string {
	// In a real implementation, this would get the API URL from environment variables
	return "https://api.privado.ai"
}

// PrivadoClient handles communication with the Privado ID API
type PrivadoClient struct {
	apiKey string
	apiURL string
	client *http.Client
}

// NewPrivadoClient creates a new Privado API client
func NewPrivadoClient(apiKey, apiURL string) *PrivadoClient {
	return &PrivadoClient{
		apiKey: apiKey,
		apiURL: apiURL,
		client: &http.Client{
			Timeout: 10 * time.Second,
		},
	}
}

// PrivadoZKPVerificationRequest represents a request to verify a ZKP token
type PrivadoZKPVerificationRequest struct {
	ZKPToken string `json:"zkpToken"`
}

// PrivadoZKPVerificationResponse represents the response from Privado ID verification
type PrivadoZKPVerificationResponse struct {
	Verified bool   `json:"verified"`
	Error    string `json:"error,omitempty"`
}

// VerifyZKP verifies a ZKP token with Privado ID
// In a production implementation, this would make real API calls to Privado ID
func (c *PrivadoClient) VerifyZKP(ctx context.Context, zkpToken string) (bool, error) {
	// For development/testing: you can implement a mock response here
	// In production, replace this with actual API calls to Privado ID

	// Mock implementation for testing
	if zkpToken == "invalid-token" {
		return false, errors.New("invalid ZKP proof")
	}

	if zkpToken == "error-token" {
		return false, errors.New("verification service unavailable")
	}

	return zkpToken != "", nil

	/*
		// Real implementation would look something like this:
		reqBody, err := json.Marshal(PrivadoZKPVerificationRequest{
			ZKPToken: zkpToken,
		})
		if err != nil {
			return false, fmt.Errorf("failed to marshal request: %v", err)
		}

		req, err := http.NewRequestWithContext(ctx, "POST", c.apiURL+"/verify-zkp", bytes.NewBuffer(reqBody))
		if err != nil {
			return false, fmt.Errorf("failed to create request: %v", err)
		}

		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("X-API-Key", c.apiKey)

		resp, err := c.client.Do(req)
		if err != nil {
			return false, fmt.Errorf("failed to send request: %v", err)
		}
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusOK {
			return false, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
		}

		var verificationResp PrivadoZKPVerificationResponse
		if err := json.NewDecoder(resp.Body).Decode(&verificationResp); err != nil {
			return false, fmt.Errorf("failed to decode response: %v", err)
		}

		if verificationResp.Error != "" {
			return false, errors.New(verificationResp.Error)
		}

		return verificationResp.Verified, nil
	*/
}