package commands

import (
	"fmt"
	"os"
	"path/filepath"

	"git.dws.rip/DWS/onyx/internal/core"
	"git.dws.rip/DWS/onyx/internal/storage"
	"github.com/go-git/go-git/v5/config"
	"github.com/spf13/cobra"
)

// NewInitCmd creates the init command
func NewInitCmd() *cobra.Command {
	var remoteURL string

	cmd := &cobra.Command{
		Use:   "init [path]",
		Short: "Initialize a new Onyx repository",
		Long: `Initialize a new Onyx repository in the specified directory.
If no path is provided, initializes in the current directory.

This command will:
  - Create a Git repository (if one doesn't exist)
  - Create the .onx directory structure
  - Initialize the oplog file
  - Create default workstreams.json
  - Add .onx to .gitignore
  - Optionally configure a remote repository

Example:
  onx init
  onx init --remote https://git.dws.rip/DWS/onyx.git`,
		Args: cobra.MaximumNArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			return runInit(cmd, args, remoteURL)
		},
	}

	cmd.Flags().StringVarP(&remoteURL, "remote", "r", "", "Remote repository URL to configure as 'origin'")

	return cmd
}

func runInit(cmd *cobra.Command, args []string, remoteURL string) error {
	// Determine the path
	path := "."
	if len(args) > 0 {
		path = args[0]
	}

	// Resolve to absolute path
	absPath, err := filepath.Abs(path)
	if err != nil {
		return fmt.Errorf("failed to resolve path: %w", err)
	}

	// Check if already an Onyx repository
	if core.IsOnyxRepo(absPath) {
		return fmt.Errorf("already an onyx repository: %s", absPath)
	}

	// Create and initialize repository
	repo := &core.OnyxRepository{}
	err = repo.Init(absPath)
	if err != nil {
		return fmt.Errorf("failed to initialize repository: %w", err)
	}

	// Add remote if specified
	if remoteURL != "" {
		gitRepo := repo.GetGitRepo()
		_, err = gitRepo.CreateRemote(&config.RemoteConfig{
			Name: "origin",
			URLs: []string{remoteURL},
		})
		if err != nil {
			// Don't fail the init, but warn the user
			fmt.Fprintf(os.Stderr, "Warning: failed to add remote: %v\n", err)
		} else {
			fmt.Printf("Added remote 'origin': %s\n", remoteURL)
		}
	}

	// Create default workstream matching the current Git branch
	wsManager := core.NewWorkstreamManager(repo)
	if err := wsManager.CreateDefaultWorkstream(); err != nil {
		// Don't fail init if workstream creation fails, just warn
		fmt.Fprintf(os.Stderr, "Warning: failed to create default workstream: %v\n", err)
	}

	// Add .onx to .gitignore
	gitignorePath := filepath.Join(absPath, ".gitignore")
	err = addToGitignore(gitignorePath, ".onx/")
	if err != nil {
		// Don't fail if we can't update .gitignore, just warn
		fmt.Fprintf(os.Stderr, "Warning: failed to update .gitignore: %v\n", err)
	}

	// Log the init operation to oplog
	txn, err := core.NewTransaction(repo)
	if err != nil {
		// Don't fail if we can't create transaction, repo is already initialized
		fmt.Fprintf(os.Stderr, "Warning: failed to log init to oplog: %v\n", err)
	} else {
		defer txn.Close()

		// Execute a no-op function just to log the init
		err = txn.ExecuteWithTransaction("init", "Initialized Onyx repository", func() error {
			return nil
		})
		if err != nil {
			fmt.Fprintf(os.Stderr, "Warning: failed to log init: %v\n", err)
		}
	}

	// Get the workstream name to display to the user
	currentWs, _ := wsManager.GetCurrentWorkstreamName()
	if currentWs == "" {
		currentWs = "master" // fallback
	}

	fmt.Printf("Initialized empty Onyx repository in %s\n", filepath.Join(absPath, ".onx"))
	fmt.Printf("\n✓ Created workstream '%s' tracking branch '%s'\n", currentWs, currentWs)

	if remoteURL != "" {
		fmt.Printf("\nYou can now:\n")
		fmt.Printf("  onx save -m \"message\"  # Save your work\n")
		fmt.Printf("  onx push                # Push to remote\n")
	} else {
		fmt.Printf("\nYou can now:\n")
		fmt.Printf("  onx save -m \"message\"  # Save your work\n")
		fmt.Printf("  onx new <name>          # Create a new workstream\n")
	}

	return nil
}

// addToGitignore adds an entry to .gitignore if it doesn't already exist
func addToGitignore(gitignorePath, entry string) error {
	// Read existing .gitignore if it exists
	var content []byte
	if _, err := os.Stat(gitignorePath); err == nil {
		content, err = os.ReadFile(gitignorePath)
		if err != nil {
			return fmt.Errorf("failed to read .gitignore: %w", err)
		}
	}

	// Check if entry already exists
	contentStr := string(content)
	if len(contentStr) > 0 && contentStr[len(contentStr)-1] != '\n' {
		contentStr += "\n"
	}

	// Add entry if it doesn't exist
	needle := entry
	if len(needle) > 0 && needle[len(needle)-1] != '\n' {
		needle += "\n"
	}

	// Simple check - not perfect but good enough
	if !containsLine(contentStr, entry) {
		contentStr += needle
	}

	// Write back to .gitignore
	err := os.WriteFile(gitignorePath, []byte(contentStr), 0644)
	if err != nil {
		return fmt.Errorf("failed to write .gitignore: %w", err)
	}

	return nil
}

// containsLine checks if a multi-line string contains a specific line
func containsLine(content, line string) bool {
	// Simple implementation - just check if the line exists as a substring
	// In the future, we might want to do line-by-line checking
	target := line
	if len(target) > 0 && target[len(target)-1] == '\n' {
		target = target[:len(target)-1]
	}

	lines := splitLines(content)
	for _, l := range lines {
		if l == target {
			return true
		}
	}
	return false
}

// splitLines splits a string into lines
func splitLines(s string) []string {
	if s == "" {
		return []string{}
	}

	var lines []string
	start := 0
	for i := 0; i < len(s); i++ {
		if s[i] == '\n' {
			lines = append(lines, s[start:i])
			start = i + 1
		}
	}

	// Add the last line if it doesn't end with newline
	if start < len(s) {
		lines = append(lines, s[start:])
	}

	return lines
}

// GetOplogWriter creates an oplog writer for the repository at the given path
func GetOplogWriter(path string) (*storage.OplogWriter, error) {
	absPath, err := filepath.Abs(path)
	if err != nil {
		return nil, fmt.Errorf("failed to resolve path: %w", err)
	}

	if !core.IsOnyxRepo(absPath) {
		return nil, fmt.Errorf("not an onyx repository: %s", absPath)
	}

	oplogPath := filepath.Join(absPath, ".onx", "oplog")
	return storage.OpenOplog(oplogPath)
}