package container

import (
	"crypto/rand"
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"github.com/sirupsen/logrus"
)

type BootcGenerator struct {
	logger     *logrus.Logger
	config     *BootcConfig
	registry   *ContainerRegistry
	signer     *ContainerSigner
	validator  *ContainerValidator
}

type BootcConfig struct {
	BaseImage     string            `json:"base_image"`
	OutputDir     string            `json:"output_dir"`
	RegistryURL  string            `json:"registry_url"`
	SigningKey   string            `json:"signing_key"`
	Compression  string            `json:"compression"`
	Metadata     map[string]string `json:"metadata"`
}

type ContainerRegistry struct {
	URL      string            `json:"url"`
	Username string            `json:"username"`
	Password string            `json:"password"`
	Insecure bool              `json:"insecure"`
	Headers  map[string]string `json:"headers"`
}

type ContainerSigner struct {
	PrivateKey string `json:"private_key"`
	PublicKey  string `json:"public_key"`
	Algorithm  string `json:"algorithm"`
}

type ContainerValidator struct {
	SecurityScan bool `json:"security_scan"`
	PolicyCheck  bool `json:"policy_check"`
	VulnerabilityScan bool `json:"vulnerability_scan"`
}

type BootcContainer struct {
	ID          string                 `json:"id"`
	Name        string                 `json:"name"`
	Tag         string                 `json:"tag"`
	Digest      string                 `json:"digest"`
	Size        int64                  `json:"size"`
	Architecture string                `json:"architecture"`
	OS          string                 `json:"os"`
	Variant     string                 `json:"variant"`
	Layers      []ContainerLayer       `json:"layers"`
	Metadata    map[string]interface{} `json:"metadata"`
	CreatedAt   time.Time              `json:"created_at"`
	Signed      bool                   `json:"signed"`
	Signature   string                 `json:"signature,omitempty"`
}

type ContainerLayer struct {
	Digest    string `json:"digest"`
	Size      int64  `json:"size"`
	MediaType string `json:"media_type"`
	Created   time.Time `json:"created"`
}

type ContainerVariant struct {
	Name        string   `json:"name"`
	Description string   `json:"description"`
	Packages    []string `json:"packages"`
	Services    []string `json:"services"`
	Config      map[string]interface{} `json:"config"`
}

func NewBootcGenerator(config *BootcConfig, logger *logrus.Logger) *BootcGenerator {
	generator := &BootcGenerator{
		logger:    logger,
		config:    config,
		registry:  NewContainerRegistry(),
		signer:    NewContainerSigner(),
		validator: NewContainerValidator(),
	}
	
	return generator
}

func NewContainerRegistry() *ContainerRegistry {
	return &ContainerRegistry{
		URL:      "localhost:5000",
		Insecure: true,
		Headers:  make(map[string]string),
	}
}

func NewContainerSigner() *ContainerSigner {
	return &ContainerSigner{
		Algorithm: "sha256",
	}
}

func NewContainerValidator() *ContainerValidator {
	return &ContainerValidator{
		SecurityScan:    true,
		PolicyCheck:     true,
		VulnerabilityScan: true,
	}
}

func (bg *BootcGenerator) GenerateContainer(blueprint *Blueprint, variant string) (*BootcContainer, error) {
	bg.logger.Infof("Generating bootc container for blueprint: %s, variant: %s", blueprint.Name, variant)
	
	// Create container structure
	container := &BootcContainer{
		ID:          generateContainerID(),
		Name:        fmt.Sprintf("%s-%s", blueprint.Name, variant),
		Tag:         "latest",
		Architecture: blueprint.Architecture,
		OS:          "linux",
		Variant:     variant,
		Layers:      []ContainerLayer{},
		Metadata:    make(map[string]interface{}),
		CreatedAt:   time.Now(),
	}
	
	// Generate container layers
	if err := bg.generateLayers(container, blueprint, variant); err != nil {
		return nil, fmt.Errorf("failed to generate layers: %w", err)
	}
	
	// Build container image
	if err := bg.buildContainer(container); err != nil {
		return nil, fmt.Errorf("failed to build container: %w", err)
	}
	
	// Sign container if configured
	if bg.config.SigningKey != "" {
		if err := bg.signContainer(container); err != nil {
			bg.logger.Warnf("Failed to sign container: %v", err)
		} else {
			container.Signed = true
		}
	}
	
	// Validate container
	if err := bg.validateContainer(container); err != nil {
		bg.logger.Warnf("Container validation failed: %v", err)
	}
	
	// Push to registry if configured
	if bg.config.RegistryURL != "" {
		if err := bg.pushToRegistry(container); err != nil {
			bg.logger.Warnf("Failed to push to registry: %v", err)
		}
	}
	
	bg.logger.Infof("Successfully generated container: %s", container.ID)
	return container, nil
}

func (bg *BootcGenerator) generateLayers(container *BootcContainer, blueprint *Blueprint, variant string) error {
	// Create base layer
	baseLayer := ContainerLayer{
		Digest:    generateDigest(),
		Size:      0,
		MediaType: "application/vnd.oci.image.layer.v1.tar+gzip",
		Created:   time.Now(),
	}
	container.Layers = append(container.Layers, baseLayer)
	
	// Create package layer
	packageLayer := ContainerLayer{
		Digest:    generateDigest(),
		Size:      0,
		MediaType: "application/vnd.oci.image.layer.v1.tar+gzip",
		Created:   time.Now(),
	}
	container.Layers = append(container.Layers, packageLayer)
	
	// Create configuration layer
	configLayer := ContainerLayer{
		Digest:    generateDigest(),
		Size:      0,
		MediaType: "application/vnd.oci.image.layer.v1.tar+gzip",
		Created:   time.Now(),
	}
	container.Layers = append(container.Layers, configLayer)
	
	// Set metadata
	container.Metadata["blueprint"] = blueprint.Name
	container.Metadata["variant"] = variant
	container.Metadata["packages"] = blueprint.Packages.Include
	container.Metadata["users"] = blueprint.Users
	container.Metadata["customizations"] = blueprint.Customizations
	
	return nil
}

func (bg *BootcGenerator) buildContainer(container *BootcContainer) error {
	// Create output directory
	outputDir := filepath.Join(bg.config.OutputDir, container.Name)
	if err := os.MkdirAll(outputDir, 0755); err != nil {
		return fmt.Errorf("failed to create output directory: %w", err)
	}
	
	// Generate Dockerfile
	dockerfilePath := filepath.Join(outputDir, "Dockerfile")
	if err := bg.generateDockerfile(dockerfilePath, container); err != nil {
		return fmt.Errorf("failed to generate Dockerfile: %w", err)
	}
	
	// Build container image
	if err := bg.dockerBuild(outputDir, container); err != nil {
		return fmt.Errorf("failed to build container: %w", err)
	}
	
	// Calculate final size
	container.Size = bg.calculateContainerSize(container)
	
	return nil
}

func (bg *BootcGenerator) generateDockerfile(path string, container *BootcContainer) error {
	content := fmt.Sprintf(`# Debian Bootc Container: %s
FROM debian:bookworm-slim

# Set metadata
LABEL org.opencontainers.image.title="%s"
LABEL org.opencontainers.image.description="Debian atomic container for %s"
LABEL org.opencontainers.image.vendor="Debian Forge"
LABEL org.opencontainers.image.version="1.0.0"

# Install packages
RUN apt-get update && apt-get install -y \\
    %s \\
    && rm -rf /var/lib/apt/lists/*

# Create users
%s

# Set customizations
%s

# Set working directory
WORKDIR /root

# Default command
CMD ["/bin/bash"]
`, container.Name, container.Name, container.Variant, 
	strings.Join(container.Metadata["packages"].([]string), " \\\n    "),
	bg.generateUserCommands(container),
	bg.generateCustomizationCommands(container))
	
	return os.WriteFile(path, []byte(content), 0644)
}

func (bg *BootcGenerator) generateUserCommands(container *BootcContainer) string {
	var commands []string
	
	if users, ok := container.Metadata["users"].([]BlueprintUser); ok {
		for _, user := range users {
			commands = append(commands, fmt.Sprintf("RUN useradd -m -s %s %s", user.Shell, user.Name))
		}
	}
	
	return strings.Join(commands, "\n")
}

func (bg *BootcGenerator) generateCustomizationCommands(container *BootcContainer) string {
	var commands []string
	
	if customizations, ok := container.Metadata["customizations"].(BlueprintCustomizations); ok {
		if customizations.Hostname != "" {
			commands = append(commands, fmt.Sprintf("RUN echo '%s' > /etc/hostname", customizations.Hostname))
		}
		if customizations.Timezone != "" {
			commands = append(commands, fmt.Sprintf("RUN ln -sf /usr/share/zoneinfo/%s /etc/localtime", customizations.Timezone))
		}
	}
	
	return strings.Join(commands, "\n")
}

func (bg *BootcGenerator) dockerBuild(context string, container *BootcContainer) error {
	// Build command
	cmd := exec.Command("docker", "build", "-t", container.Name+":"+container.Tag, context)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	
	if err := cmd.Run(); err != nil {
		return fmt.Errorf("docker build failed: %w", err)
	}
	
	// Get image digest
	digestCmd := exec.Command("docker", "images", "--digests", "--format", "{{.Digest}}", container.Name+":"+container.Tag)
	digestOutput, err := digestCmd.Output()
	if err != nil {
		bg.logger.Warnf("Failed to get image digest: %v", err)
	} else {
		container.Digest = strings.TrimSpace(string(digestOutput))
	}
	
	return nil
}

func (bg *BootcGenerator) calculateContainerSize(container *BootcContainer) int64 {
	// Get image size from Docker
	cmd := exec.Command("docker", "images", "--format", "{{.Size}}", container.Name+":"+container.Tag)
	output, err := cmd.Output()
	if err != nil {
		bg.logger.Warnf("Failed to get image size: %v", err)
		return 0
	}
	
	// Parse size (e.g., "123.4MB" -> 123400000)
	sizeStr := strings.TrimSpace(string(output))
	// Simple size parsing - in production, use proper size parsing library
	return 0 // Placeholder
}

func (bg *BootcGenerator) signContainer(container *BootcContainer) error {
	if bg.signer.PrivateKey == "" {
		return fmt.Errorf("no signing key configured")
	}
	
	// Use cosign to sign the container
	cmd := exec.Command("cosign", "sign", "--key", bg.signer.PrivateKey, 
		container.Name+":"+container.Tag)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	
	if err := cmd.Run(); err != nil {
		return fmt.Errorf("cosign signing failed: %w", err)
	}
	
	// Get signature
	signatureCmd := exec.Command("cosign", "verify", "--key", bg.signer.PublicKey, 
		container.Name+":"+container.Tag)
	signatureOutput, err := signatureCmd.Output()
	if err != nil {
		return fmt.Errorf("failed to verify signature: %w", err)
	}
	
	container.Signature = strings.TrimSpace(string(signatureOutput))
	return nil
}

func (bg *BootcGenerator) validateContainer(container *BootcContainer) error {
	if !bg.validator.SecurityScan {
		return nil
	}
	
	// Run security scan
	if err := bg.runSecurityScan(container); err != nil {
		return fmt.Errorf("security scan failed: %w", err)
	}
	
	// Run policy check
	if bg.validator.PolicyCheck {
		if err := bg.runPolicyCheck(container); err != nil {
			return fmt.Errorf("policy check failed: %w", err)
		}
	}
	
	// Run vulnerability scan
	if bg.validator.VulnerabilityScan {
		if err := bg.runVulnerabilityScan(container); err != nil {
			return fmt.Errorf("vulnerability scan failed: %w", err)
		}
	}
	
	return nil
}

func (bg *BootcGenerator) runSecurityScan(container *BootcContainer) error {
	// Use Trivy for security scanning
	cmd := exec.Command("trivy", "image", "--format", "json", 
		container.Name+":"+container.Tag)
	output, err := cmd.Output()
	if err != nil {
		return fmt.Errorf("trivy scan failed: %w", err)
	}
	
	// Parse scan results
	var scanResults map[string]interface{}
	if err := json.Unmarshal(output, &scanResults); err != nil {
		return fmt.Errorf("failed to parse scan results: %w", err)
	}
	
	// Check for high/critical vulnerabilities
	if vulnerabilities, ok := scanResults["Vulnerabilities"].([]interface{}); ok {
		for _, vuln := range vulnerabilities {
			if vulnMap, ok := vuln.(map[string]interface{}); ok {
				if severity, ok := vulnMap["Severity"].(string); ok {
					if severity == "HIGH" || severity == "CRITICAL" {
						bg.logger.Warnf("High/Critical vulnerability found: %v", vulnMap)
					}
				}
			}
		}
	}
	
	return nil
}

func (bg *BootcGenerator) runPolicyCheck(container *BootcContainer) error {
	// Use Open Policy Agent for policy checking
	// This is a placeholder - implement actual policy checking
	bg.logger.Info("Running policy check on container")
	return nil
}

func (bg *BootcGenerator) runVulnerabilityScan(container *BootcContainer) error {
	// Use Grype for vulnerability scanning
	cmd := exec.Command("grype", "--output", "json", container.Name+":"+container.Tag)
	output, err := cmd.Output()
	if err != nil {
		return fmt.Errorf("grype scan failed: %w", err)
	}
	
	// Parse vulnerability results
	var vulnResults map[string]interface{}
	if err := json.Unmarshal(output, &vulnResults); err != nil {
		return fmt.Errorf("failed to parse vulnerability results: %w", err)
	}
	
	// Process vulnerabilities
	bg.logger.Infof("Vulnerability scan completed for container: %s", container.Name)
	return nil
}

func (bg *BootcGenerator) pushToRegistry(container *BootcContainer) error {
	// Tag for registry
	registryTag := fmt.Sprintf("%s/%s:%s", bg.config.RegistryURL, container.Name, container.Tag)
	
	// Tag image
	tagCmd := exec.Command("docker", "tag", container.Name+":"+container.Tag, registryTag)
	if err := tagCmd.Run(); err != nil {
		return fmt.Errorf("failed to tag image: %w", err)
	}
	
	// Push to registry
	pushCmd := exec.Command("docker", "push", registryTag)
	pushCmd.Stdout = os.Stdout
	pushCmd.Stderr = os.Stderr
	
	if err := pushCmd.Run(); err != nil {
		return fmt.Errorf("failed to push image: %w", err)
	}
	
	bg.logger.Infof("Successfully pushed container to registry: %s", registryTag)
	return nil
}

func (bg *BootcGenerator) ListContainerVariants() []ContainerVariant {
	return []ContainerVariant{
		{
			Name:        "minimal",
			Description: "Minimal Debian system without desktop environment",
			Packages:    []string{"task-minimal", "systemd", "systemd-sysv"},
			Services:    []string{"systemd-sysctl", "systemd-random-seed"},
			Config: map[string]interface{}{
				"hostname": "debian-minimal",
				"timezone": "UTC",
			},
		},
		{
			Name:        "desktop",
			Description: "Debian with desktop environment",
			Packages:    []string{"task-gnome-desktop", "gnome-core", "systemd"},
			Services:    []string{"gdm", "systemd-sysctl"},
			Config: map[string]interface{}{
				"hostname": "debian-desktop",
				"timezone": "UTC",
				"desktop":  "gnome",
			},
		},
		{
			Name:        "server",
			Description: "Server-optimized Debian system",
			Packages:    []string{"task-server", "systemd", "openssh-server"},
			Services:    []string{"ssh", "systemd-sysctl"},
			Config: map[string]interface{}{
				"hostname": "debian-server",
				"timezone": "UTC",
				"ssh":      true,
			},
		},
		{
			Name:        "development",
			Description: "Development environment Debian system",
			Packages:    []string{"build-essential", "git", "python3", "nodejs"},
			Services:    []string{"systemd-sysctl"},
			Config: map[string]interface{}{
				"hostname": "debian-dev",
				"timezone": "UTC",
				"dev_tools": true,
			},
		},
	}
}

func (bg *BootcGenerator) GetContainerInfo(containerID string) (*BootcContainer, error) {
	// Get container information from Docker
	cmd := exec.Command("docker", "inspect", containerID)
	output, err := cmd.Output()
	if err != nil {
		return nil, fmt.Errorf("failed to inspect container: %w", err)
	}
	
	// Parse inspect output
	var inspectResults []map[string]interface{}
	if err := json.Unmarshal(output, &inspectResults); err != nil {
		return nil, fmt.Errorf("failed to parse inspect results: %w", err)
	}
	
	if len(inspectResults) == 0 {
		return nil, fmt.Errorf("container not found")
	}
	
	// Convert to our container structure
	container := &BootcContainer{
		ID:          containerID,
		Name:        inspectResults[0]["Name"].(string),
		CreatedAt:   time.Now(), // Parse from inspect results
		Metadata:    make(map[string]interface{}),
	}
	
	return container, nil
}

// Helper functions
func generateContainerID() string {
	bytes := make([]byte, 16)
	rand.Read(bytes)
	return fmt.Sprintf("%x", bytes)
}

func generateDigest() string {
	bytes := make([]byte, 32)
	rand.Read(bytes)
	return fmt.Sprintf("sha256:%x", bytes)
}

// Blueprint types (imported from blueprintapi)
type Blueprint struct {
	Name        string                 `json:"name"`
	Packages    BlueprintPackages      `json:"packages"`
	Users       []BlueprintUser        `json:"users"`
	Customizations BlueprintCustomizations `json:"customizations"`
}

type BlueprintPackages struct {
	Include []string `json:"include"`
}

type BlueprintUser struct {
	Name  string `json:"name"`
	Shell string `json:"shell"`
}

type BlueprintCustomizations struct {
	Hostname string `json:"hostname"`
	Timezone string `json:"timezone"`
}