package f5

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"net/http"
	"time"

	"github.com/shankar0123/certctl/internal/connector/target"
)

// Config represents the F5 BIG-IP deployment target configuration.
type Config struct {
	Host       string `json:"host"`        // F5 BIG-IP hostname or IP
	Port       int    `json:"port"`        // F5 iControl REST API port (default 443)
	Username   string `json:"username"`    // Administrative username
	Password   string `json:"password"`    // Administrative password
	Partition  string `json:"partition"`   // F5 partition name (e.g., "Common")
	SSLProfile string `json:"ssl_profile"` // SSL profile name to update
}

// Connector implements the target.Connector interface for F5 BIG-IP load balancers.
// This connector communicates with F5's iControl REST API to upload certificates and manage SSL profiles.
//
// TODO: Implement actual F5 iControl REST API communication.
// The documented API endpoints and flow are:
//   - Authentication: POST /mgmt/shared/authn/login
//   - Upload certificate: POST /mgmt/tm/ltm/certificate
//   - Update SSL profile: PATCH /mgmt/tm/ltm/profile/client-ssl/{profile_name}
//   - Check SSL profile: GET /mgmt/tm/ltm/profile/client-ssl/{profile_name}
type Connector struct {
	config *Config
	logger *slog.Logger
	client *http.Client
}

// New creates a new F5 target connector with the given configuration and logger.
func New(config *Config, logger *slog.Logger) *Connector {
	return &Connector{
		config: config,
		logger: logger,
		client: &http.Client{
			Timeout: 30 * time.Second,
			// TODO: Configure proper TLS verification or skip for self-signed F5 certs
		},
	}
}

// ValidateConfig checks that the F5 BIG-IP is reachable and credentials are valid.
// It attempts to authenticate to the F5 iControl REST API.
//
// TODO: Implement actual F5 authentication validation.
func (c *Connector) ValidateConfig(ctx context.Context, rawConfig json.RawMessage) error {
	var cfg Config
	if err := json.Unmarshal(rawConfig, &cfg); err != nil {
		return fmt.Errorf("invalid F5 config: %w", err)
	}

	if cfg.Host == "" || cfg.Username == "" || cfg.Password == "" {
		return fmt.Errorf("F5 host, username, and password are required")
	}

	if cfg.Port == 0 {
		cfg.Port = 443 // Default HTTPS port
	}

	if cfg.Partition == "" {
		cfg.Partition = "Common"
	}

	c.logger.Info("validating F5 configuration",
		"host", cfg.Host,
		"port", cfg.Port,
		"partition", cfg.Partition)

	// TODO: Implement F5 authentication check
	// In production:
	//   1. POST to https://{host}:{port}/mgmt/shared/authn/login
	//   2. Send credentials in request body
	//   3. Verify response contains valid authentication token
	//   4. Optionally test connectivity to SSL profile endpoint

	c.logger.Warn("F5 validation not yet fully implemented",
		"host", cfg.Host)

	c.config = &cfg
	return nil
}

// DeployCertificate uploads a certificate to the F5 BIG-IP and updates the specified SSL profile.
//
// The F5 deployment process:
// 1. Authenticate to iControl REST API using credentials
// 2. Upload certificate PEM to /mgmt/tm/ltm/certificate
// 3. Upload chain PEM as separate certificate if needed
// 4. Update the target SSL profile to reference the new certificate
// 5. Verify the profile was updated successfully
//
// TODO: Implement actual F5 iControl REST API calls.
// API endpoints used:
//   - POST /mgmt/shared/authn/login (authentication)
//   - POST /mgmt/tm/ltm/certificate (upload cert)
//   - PATCH /mgmt/tm/ltm/profile/client-ssl/{SSLProfile} (update profile)
func (c *Connector) DeployCertificate(ctx context.Context, request target.DeploymentRequest) (*target.DeploymentResult, error) {
	c.logger.Info("deploying certificate to F5 BIG-IP",
		"host", c.config.Host,
		"partition", c.config.Partition,
		"ssl_profile", c.config.SSLProfile)

	startTime := time.Now()

	// TODO: Implement F5 certificate deployment
	// In production:
	//   1. Authenticate to F5: POST /mgmt/shared/authn/login
	//   2. Create certificate object:
	//      POST /mgmt/tm/ltm/certificate
	//      Body: {"name": "certctl-cert-{timestamp}", "certificateText": "{CertPEM}"}
	//   3. If chain is provided, upload as separate certificate:
	//      POST /mgmt/tm/ltm/certificate
	//      Body: {"name": "certctl-chain-{timestamp}", "certificateText": "{ChainPEM}"}
	//   4. Update SSL profile:
	//      PATCH /mgmt/tm/ltm/profile/client-ssl/{SSLProfile}
	//      Body: {"certificate": "/Common/certctl-cert-{timestamp}"}
	//   5. Verify deployment by checking profile status

	deploymentDuration := time.Since(startTime)

	c.logger.Warn("F5 deployment not yet implemented",
		"host", c.config.Host,
		"ssl_profile", c.config.SSLProfile)

	return &target.DeploymentResult{
		Success:       true,
		TargetAddress: fmt.Sprintf("%s:%d", c.config.Host, c.config.Port),
		DeploymentID:  fmt.Sprintf("f5-%d", time.Now().Unix()),
		Message:       "Certificate deployment to F5 initiated (stub)",
		DeployedAt:    time.Now(),
		Metadata: map[string]string{
			"host":        c.config.Host,
			"partition":   c.config.Partition,
			"ssl_profile": c.config.SSLProfile,
			"duration_ms": fmt.Sprintf("%d", deploymentDuration.Milliseconds()),
		},
	}, nil
}

// ValidateDeployment verifies that the certificate is properly deployed on the F5 BIG-IP.
// It checks the SSL profile configuration to ensure it references the correct certificate.
//
// TODO: Implement actual F5 validation via iControl REST API.
// API endpoint used:
//   - GET /mgmt/tm/ltm/profile/client-ssl/{SSLProfile}
func (c *Connector) ValidateDeployment(ctx context.Context, request target.ValidationRequest) (*target.ValidationResult, error) {
	c.logger.Info("validating F5 deployment",
		"certificate_id", request.CertificateID,
		"serial", request.Serial,
		"ssl_profile", c.config.SSLProfile)

	startTime := time.Now()

	// TODO: Implement F5 deployment validation
	// In production:
	//   1. Authenticate to F5: POST /mgmt/shared/authn/login
	//   2. Query SSL profile:
	//      GET /mgmt/tm/ltm/profile/client-ssl/{SSLProfile}
	//   3. Verify the response includes the expected certificate name
	//   4. Optionally check certificate validity dates
	//   5. Verify the profile is in active use (no errors/warnings)

	validationDuration := time.Since(startTime)

	c.logger.Warn("F5 validation not yet implemented",
		"ssl_profile", c.config.SSLProfile)

	return &target.ValidationResult{
		Valid:         true,
		Serial:        request.Serial,
		TargetAddress: fmt.Sprintf("%s:%d", c.config.Host, c.config.Port),
		Message:       "Certificate deployment validation initiated (stub)",
		ValidatedAt:   time.Now(),
		Metadata: map[string]string{
			"host":        c.config.Host,
			"ssl_profile": c.config.SSLProfile,
			"duration_ms": fmt.Sprintf("%d", validationDuration.Milliseconds()),
		},
	}, nil
}
