// Package service provides business logic services.
package service

import (
	"context"
	"database/sql"
	"encoding/base64"
	"fmt"
	"log/slog"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"

	giteaadapter "github.com/orchard9/rdev/internal/adapter/gitea"
	"github.com/orchard9/rdev/internal/domain"
	"github.com/orchard9/rdev/internal/port"
)

// procfilePatterns contains pre-compiled regex patterns for parsing Procfile entries
// by component type. Compiled once at package init for performance.
var procfilePatterns = make(map[domain.ComponentType]*regexp.Regexp)

func init() {
	// Pre-compile regex patterns for each component type's Procfile entries
	for _, ct := range domain.ValidComponentTypes {
		destDir := ct.DestDir()
		if destDir != "" {
			// Pattern matches: "component-name: cd services/component-name && ..."
			procfilePatterns[ct] = regexp.MustCompile(`^([a-z][a-z0-9-]*): cd (` + destDir + `/[a-z0-9-]+)`)
		}
	}
}

// ComponentService manages components within monorepo projects.
type ComponentService struct {
	db               *sql.DB
	templateProvider port.TemplateProvider
	bulkClient       *giteaadapter.BulkFileClient
	deployer         port.Deployer
	defaultGitOwner  string
	registryURL      string
	logger           *slog.Logger
}

// ComponentServiceConfig configures the component service.
type ComponentServiceConfig struct {
	DefaultGitOwner string // e.g., "threesix"
	RegistryURL     string // e.g., "registry.threesix.ai"
	Logger          *slog.Logger
}

// NewComponentService creates a new component service.
func NewComponentService(
	db *sql.DB,
	templateProvider port.TemplateProvider,
	bulkClient *giteaadapter.BulkFileClient,
	deployer port.Deployer,
	cfg ComponentServiceConfig,
) *ComponentService {
	logger := cfg.Logger
	if logger == nil {
		logger = slog.Default()
	}
	return &ComponentService{
		db:               db,
		templateProvider: templateProvider,
		bulkClient:       bulkClient,
		deployer:         deployer,
		defaultGitOwner:  cfg.DefaultGitOwner,
		registryURL:      cfg.RegistryURL,
		logger:           logger,
	}
}

// Ensure ComponentService implements the interface.
var _ port.ComponentService = (*ComponentService)(nil)

// AddComponent adds a new component to a project's monorepo.
func (s *ComponentService) AddComponent(ctx context.Context, projectID string, req port.AddComponentRequest) (*domain.Component, error) {
	// 1. Validate component type
	if !domain.IsValidComponentType(req.Type) {
		return nil, fmt.Errorf("%w: %s", domain.ErrInvalidComponentType, req.Type)
	}
	componentType := domain.ComponentType(req.Type)

	// 2. Validate component name
	if err := domain.ValidateComponentName(req.Name); err != nil {
		return nil, fmt.Errorf("%w: %s", err, req.Name)
	}

	// 3. Get project info from database
	var gitRepoOwner, gitRepoName, goModule string
	var projectDomain string
	err := s.db.QueryRowContext(ctx, `
		SELECT COALESCE(git_repo_owner, $2), COALESCE(git_repo_name, $1), COALESCE(domain, '')
		FROM projects WHERE id = $1
	`, projectID, s.defaultGitOwner).Scan(&gitRepoOwner, &gitRepoName, &projectDomain)
	if err == sql.ErrNoRows {
		return nil, fmt.Errorf("%w: %s", domain.ErrProjectNotFound, projectID)
	}
	if err != nil {
		return nil, fmt.Errorf("failed to get project: %w", err)
	}

	// Build Go module path (use actual git host, not github.com)
	goModule = fmt.Sprintf("git.threesix.ai/%s/%s", gitRepoOwner, gitRepoName)

	// 4. Calculate component path
	destDir := componentType.DestDir()
	componentPath := filepath.Join(destDir, req.Name)

	// 5. Check for duplicate component by checking for key files
	checkFile := componentPath + "/go.mod"
	if componentType == domain.ComponentTypeAppAstro || componentType == domain.ComponentTypeAppReact {
		checkFile = componentPath + "/package.json"
	}
	existingContent, _, err := s.bulkClient.GetFileContent(ctx, gitRepoOwner, gitRepoName, checkFile)
	if err != nil {
		return nil, fmt.Errorf("failed to check for existing component: %w", err)
	}
	if existingContent != nil {
		return nil, fmt.Errorf("%w: %s", domain.ErrDuplicateComponent, componentPath)
	}

	// 6. Assign port if needed
	port := req.Port
	if port == 0 && componentType.NeedsPort() {
		port, err = s.assignPort(ctx, projectID, componentType)
		if err != nil {
			return nil, fmt.Errorf("failed to assign port: %w", err)
		}
	}

	// 7. Prepare template variables
	vars := map[string]string{
		"PROJECT_NAME":   projectID,
		"GO_MODULE":      goModule,
		"COMPONENT_NAME": req.Name,
		"PORT":           strconv.Itoa(port),
		"DOMAIN":         projectDomain,
	}

	// 8. Get component template files
	componentFiles, err := s.templateProvider.GetComponentFiles(ctx, req.Type, componentPath, vars)
	if err != nil {
		return nil, fmt.Errorf("failed to get component template files: %w", err)
	}

	// 9. Read and update monorepo files
	fileOps, err := s.prepareMonorepoUpdates(ctx, gitRepoOwner, gitRepoName, componentType, req.Name, componentPath, port, vars)
	if err != nil {
		return nil, fmt.Errorf("failed to prepare monorepo updates: %w", err)
	}

	// 10. Add component files to the operations
	for _, cf := range componentFiles {
		// Skip the .woodpecker.step.yml file - it's merged into main .woodpecker.yml
		if strings.HasSuffix(cf.Path, ".woodpecker.step.yml") {
			continue
		}
		encodedContent := base64.StdEncoding.EncodeToString([]byte(cf.Content))
		fileOps = append(fileOps, giteaadapter.ChangeFileOperation{
			Operation: "create",
			Path:      cf.Path,
			Content:   encodedContent,
		})
	}

	// 11. Commit all files in a single atomic commit
	opts := giteaadapter.ChangeFilesOptions{
		Files:   fileOps,
		Message: fmt.Sprintf("Add %s component: %s", req.Type, req.Name),
	}

	_, err = s.bulkClient.ChangeFiles(ctx, gitRepoOwner, gitRepoName, opts)
	if err != nil {
		return nil, fmt.Errorf("failed to commit component files: %w", err)
	}

	s.logger.Info("component added successfully",
		"project", projectID,
		"component_type", req.Type,
		"component_name", req.Name,
		"path", componentPath,
		"port", port,
	)

	// 12. Build and return the component
	component := &domain.Component{
		Type:         componentType,
		Name:         req.Name,
		Path:         componentPath,
		Port:         port,
		Template:     req.Type,
		Dependencies: []string{}, // Could be parsed from component.yaml
	}

	// 13. Create initial K8s deployment for components that need one.
	// This ensures kubectl set image will find the deployment when CI runs.
	s.createInitialComponentDeployment(ctx, projectID, projectDomain, component)

	return component, nil
}

// assignPort finds the next available port for a component type.
func (s *ComponentService) assignPort(ctx context.Context, projectID string, componentType domain.ComponentType) (int, error) {
	// Get existing components to find the highest used port
	components, err := s.ListComponents(ctx, projectID)
	if err != nil {
		return 0, err
	}

	startingPort := componentType.StartingPort()
	if startingPort == 0 {
		return 0, nil // Component type doesn't need a port
	}

	maxPort := startingPort - 1
	for _, c := range components {
		// Only consider components that share the same port range
		if c.Type.StartingPort() == startingPort && c.Port > maxPort {
			maxPort = c.Port
		}
	}

	return maxPort + 1, nil
}

// createInitialComponentDeployment creates a K8s Deployment for a newly added component.
// This ensures the deployment exists before CI runs, so kubectl set image succeeds.
// Failures are logged but don't fail the component creation.
func (s *ComponentService) createInitialComponentDeployment(
	ctx context.Context,
	projectID, projectDomain string,
	component *domain.Component,
) {
	// Skip if no deployer or component doesn't need a deployment
	if s.deployer == nil || !component.Type.NeedsPort() {
		return
	}

	// Build the image path - uses "latest" as placeholder until CI builds a real image
	image := fmt.Sprintf("%s/%s/%s:latest", s.registryURL, projectID, component.Name)

	spec := domain.DeploySpec{
		ProjectName:   projectID,
		ComponentPath: component.Path,
		Image:         image,
		Domain:        projectDomain,
		Port:          component.Port,
		Replicas:      1,
	}

	if err := s.deployer.Deploy(ctx, spec); err != nil {
		s.logger.Warn("failed to create initial component deployment",
			"project", projectID,
			"component", component.Name,
			"error", err,
		)
		return
	}

	s.logger.Info("created initial component deployment",
		"project", projectID,
		"component", component.Name,
		"image", image,
	)
}

// prepareMonorepoUpdates reads existing monorepo files and prepares updates.
func (s *ComponentService) prepareMonorepoUpdates(
	ctx context.Context,
	owner, repo string,
	componentType domain.ComponentType,
	componentName, componentPath string,
	port int,
	vars map[string]string,
) ([]giteaadapter.ChangeFileOperation, error) {
	var fileOps []giteaadapter.ChangeFileOperation

	// 1. Update Procfile
	procfileContent, procfileSHA, err := s.bulkClient.GetFileContent(ctx, owner, repo, "Procfile")
	if err != nil {
		return nil, fmt.Errorf("failed to get Procfile: %w", err)
	}
	if procfileContent != nil {
		updated := s.updateProcfile(string(procfileContent), componentType, componentName, componentPath, port)
		fileOps = append(fileOps, giteaadapter.ChangeFileOperation{
			Operation: "update",
			Path:      "Procfile",
			Content:   base64.StdEncoding.EncodeToString([]byte(updated)),
			SHA:       procfileSHA,
		})
	}

	// 2. Update go.work for Go components
	if componentType.IsGoComponent() {
		goWorkContent, goWorkSHA, err := s.bulkClient.GetFileContent(ctx, owner, repo, "go.work")
		if err != nil {
			return nil, fmt.Errorf("failed to get go.work: %w", err)
		}
		if goWorkContent != nil {
			updated := s.updateGoWork(string(goWorkContent), componentPath)
			fileOps = append(fileOps, giteaadapter.ChangeFileOperation{
				Operation: "update",
				Path:      "go.work",
				Content:   base64.StdEncoding.EncodeToString([]byte(updated)),
				SHA:       goWorkSHA,
			})
		}
	}

	// 3. Update .woodpecker.yml
	woodpeckerContent, woodpeckerSHA, err := s.bulkClient.GetFileContent(ctx, owner, repo, ".woodpecker.yml")
	if err != nil {
		return nil, fmt.Errorf("failed to get .woodpecker.yml: %w", err)
	}
	if woodpeckerContent != nil {
		// Get the CI step template for this component type
		stepYaml, err := s.templateProvider.GetComponentWoodpeckerStep(ctx, string(componentType), vars)
		if err != nil {
			s.logger.Warn("failed to get woodpecker step template", "error", err)
		} else {
			updated := s.updateWoodpeckerYml(string(woodpeckerContent), stepYaml)
			fileOps = append(fileOps, giteaadapter.ChangeFileOperation{
				Operation: "update",
				Path:      ".woodpecker.yml",
				Content:   base64.StdEncoding.EncodeToString([]byte(updated)),
				SHA:       woodpeckerSHA,
			})
		}
	}

	// 4. Update CLAUDE.md
	claudeMdContent, claudeMdSHA, err := s.bulkClient.GetFileContent(ctx, owner, repo, "CLAUDE.md")
	if err != nil {
		return nil, fmt.Errorf("failed to get CLAUDE.md: %w", err)
	}
	if claudeMdContent != nil {
		updated := s.updateClaudeMd(string(claudeMdContent), componentType, componentName, componentPath)
		fileOps = append(fileOps, giteaadapter.ChangeFileOperation{
			Operation: "update",
			Path:      "CLAUDE.md",
			Content:   base64.StdEncoding.EncodeToString([]byte(updated)),
			SHA:       claudeMdSHA,
		})
	}

	return fileOps, nil
}

// ListComponents lists all components in a project's monorepo.
func (s *ComponentService) ListComponents(ctx context.Context, projectID string) ([]domain.Component, error) {
	// Get project info from database
	var gitRepoOwner, gitRepoName string
	err := s.db.QueryRowContext(ctx, `
		SELECT COALESCE(git_repo_owner, $2), COALESCE(git_repo_name, $1)
		FROM projects WHERE id = $1
	`, projectID, s.defaultGitOwner).Scan(&gitRepoOwner, &gitRepoName)
	if err == sql.ErrNoRows {
		return nil, fmt.Errorf("%w: %s", domain.ErrProjectNotFound, projectID)
	}
	if err != nil {
		return nil, fmt.Errorf("failed to get project: %w", err)
	}

	// Read Procfile once (not inside the loop)
	procfileContent, _, err := s.bulkClient.GetFileContent(ctx, gitRepoOwner, gitRepoName, "Procfile")
	if err != nil {
		s.logger.Warn("failed to read Procfile", "error", err)
		return []domain.Component{}, nil
	}
	if procfileContent == nil {
		return []domain.Component{}, nil
	}

	var components []domain.Component
	procfileStr := string(procfileContent)

	// Check each component type's directory
	for _, ct := range domain.ValidComponentTypes {
		destDir := ct.DestDir()
		if destDir == "" {
			continue
		}

		// Parse Procfile to extract component info for this type
		comps := s.parseComponentsFromProcfile(procfileStr, ct)
		components = append(components, comps...)
	}

	return components, nil
}

// parseComponentsFromProcfile extracts component information from a Procfile.
// Ports are assigned incrementally based on discovery order within each component type.
func (s *ComponentService) parseComponentsFromProcfile(procfile string, componentType domain.ComponentType) []domain.Component {
	var components []domain.Component

	// Use pre-compiled pattern from package-level map
	pattern, ok := procfilePatterns[componentType]
	if !ok {
		return components
	}

	startingPort := componentType.StartingPort()
	portOffset := 0

	for _, line := range strings.Split(procfile, "\n") {
		matches := pattern.FindStringSubmatch(strings.TrimSpace(line))
		if len(matches) >= 3 {
			name := matches[1]
			path := matches[2]

			// Assign ports incrementally based on discovery order
			port := 0
			if componentType.NeedsPort() {
				port = startingPort + portOffset
				portOffset++
			}

			components = append(components, domain.Component{
				Type:         componentType,
				Name:         name,
				Path:         path,
				Port:         port,
				Template:     string(componentType),
				Dependencies: []string{},
			})
		}
	}

	return components
}

// RemoveComponent removes a component from a project's monorepo.
func (s *ComponentService) RemoveComponent(ctx context.Context, projectID string, componentPath string) error {
	// Get project info from database
	var gitRepoOwner, gitRepoName string
	err := s.db.QueryRowContext(ctx, `
		SELECT COALESCE(git_repo_owner, $2), COALESCE(git_repo_name, $1)
		FROM projects WHERE id = $1
	`, projectID, s.defaultGitOwner).Scan(&gitRepoOwner, &gitRepoName)
	if err == sql.ErrNoRows {
		return fmt.Errorf("%w: %s", domain.ErrProjectNotFound, projectID)
	}
	if err != nil {
		return fmt.Errorf("failed to get project: %w", err)
	}

	// Verify component exists by checking for a file in the path
	checkFile := componentPath + "/go.mod"
	content, _, err := s.bulkClient.GetFileContent(ctx, gitRepoOwner, gitRepoName, checkFile)
	if err != nil {
		return fmt.Errorf("failed to check component: %w", err)
	}
	if content == nil {
		// Try package.json for frontend apps
		checkFile = componentPath + "/package.json"
		content, _, err = s.bulkClient.GetFileContent(ctx, gitRepoOwner, gitRepoName, checkFile)
		if err != nil {
			return fmt.Errorf("failed to check component: %w", err)
		}
		if content == nil {
			return fmt.Errorf("%w: %s", domain.ErrComponentNotFound, componentPath)
		}
	}

	// Extract component name from path
	componentName := filepath.Base(componentPath)

	// Determine component type from path
	var componentType domain.ComponentType
	switch {
	case strings.HasPrefix(componentPath, "services/"):
		componentType = domain.ComponentTypeService
	case strings.HasPrefix(componentPath, "workers/"):
		componentType = domain.ComponentTypeWorker
	case strings.HasPrefix(componentPath, "apps/"):
		// Could be astro or react - check package.json later
		componentType = domain.ComponentTypeAppAstro
	case strings.HasPrefix(componentPath, "cli/"):
		componentType = domain.ComponentTypeCLI
	default:
		return fmt.Errorf("unknown component path structure: %s", componentPath)
	}

	// For now, we'll update the monorepo files to remove references
	// Actual file deletion would require listing all files in the directory
	// which the Gitea API doesn't support easily

	var fileOps []giteaadapter.ChangeFileOperation

	// 1. Update Procfile - remove the component entry
	procfileContent, procfileSHA, err := s.bulkClient.GetFileContent(ctx, gitRepoOwner, gitRepoName, "Procfile")
	if err != nil {
		return fmt.Errorf("failed to get Procfile: %w", err)
	}
	if procfileContent != nil {
		updated := s.removeProcfileEntry(string(procfileContent), componentName)
		fileOps = append(fileOps, giteaadapter.ChangeFileOperation{
			Operation: "update",
			Path:      "Procfile",
			Content:   base64.StdEncoding.EncodeToString([]byte(updated)),
			SHA:       procfileSHA,
		})
	}

	// 2. Update go.work if Go component
	if componentType.IsGoComponent() {
		goWorkContent, goWorkSHA, err := s.bulkClient.GetFileContent(ctx, gitRepoOwner, gitRepoName, "go.work")
		if err != nil {
			return fmt.Errorf("failed to get go.work: %w", err)
		}
		if goWorkContent != nil {
			updated := s.removeGoWorkEntry(string(goWorkContent), componentPath)
			fileOps = append(fileOps, giteaadapter.ChangeFileOperation{
				Operation: "update",
				Path:      "go.work",
				Content:   base64.StdEncoding.EncodeToString([]byte(updated)),
				SHA:       goWorkSHA,
			})
		}
	}

	// Note: Removing from .woodpecker.yml and CLAUDE.md is more complex
	// because we'd need to parse YAML and markdown tables properly.
	// For now, we'll leave those as manual cleanup tasks.

	if len(fileOps) > 0 {
		opts := giteaadapter.ChangeFilesOptions{
			Files:   fileOps,
			Message: fmt.Sprintf("Remove component references: %s", componentName),
		}

		_, err = s.bulkClient.ChangeFiles(ctx, gitRepoOwner, gitRepoName, opts)
		if err != nil {
			return fmt.Errorf("failed to commit changes: %w", err)
		}
	}

	s.logger.Info("component removed",
		"project", projectID,
		"path", componentPath,
		"note", "Component files remain in repo - delete manually if needed",
	)

	return nil
}