package cmd

import (
	"bufio"
	"fmt"
	"os"
	"strings"
	"time"

	"git.jnss.me/joakim/opal/internal/engine"
	"git.jnss.me/joakim/opal/internal/sync"
	"github.com/google/uuid"
	"github.com/spf13/cobra"
)

var (
	quietFlag bool
)

var syncCmd = &cobra.Command{
	Use:   "sync",
	Short: "Sync tasks with remote server",
	Long:  `Manage synchronization with the opal API server`,
}

// opal sync init
var syncInitCmd = &cobra.Command{
	Use:   "init",
	Short: "Configure sync with server",
	Long: `Initialize sync configuration with the opal server.

This will prompt for server URL and API key, then save the configuration.

Examples:
  opal sync init
  opal sync init --url https://opal.example.com --key oak_xxx`,
	Run: func(cmd *cobra.Command, args []string) {
		url, _ := cmd.Flags().GetString("url")
		key, _ := cmd.Flags().GetString("key")

		// Load existing config
		cfg, err := engine.GetConfig()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
			os.Exit(1)
		}

		// Prompt for URL if not provided
		if url == "" {
			fmt.Print("Enter server URL: ")
			reader := bufio.NewReader(os.Stdin)
			url, _ = reader.ReadString('\n')
			url = strings.TrimSpace(url)
		}

		// Prompt for API key if not provided
		if key == "" {
			fmt.Print("Enter API key: ")
			reader := bufio.NewReader(os.Stdin)
			key, _ = reader.ReadString('\n')
			key = strings.TrimSpace(key)
		}

		// Generate client ID if not exists
		clientID := cfg.SyncClientID
		if clientID == "" {
			clientID = uuid.New().String()
		}

		// Update config
		cfg.SyncEnabled = true
		cfg.SyncURL = url
		cfg.SyncAPIKey = key
		cfg.SyncClientID = clientID
		cfg.SyncStrategy = "last-write-wins"
		cfg.SyncQueueOffline = true

		// Save config
		if err := engine.SaveConfig(cfg); err != nil {
			fmt.Fprintf(os.Stderr, "Error saving config: %v\n", err)
			os.Exit(1)
		}

		// Test connection
		client := sync.NewClient(url, key, clientID)
		fmt.Println("\n✓ Sync configuration saved")
		fmt.Printf("  URL:       %s\n", url)
		fmt.Printf("  Client ID: %s\n", clientID)
		fmt.Printf("  Strategy:  %s\n", cfg.SyncStrategy)

		// Offer to sync now
		fmt.Print("\nRun initial sync now? [y/N]: ")
		reader := bufio.NewReader(os.Stdin)
		response, _ := reader.ReadString('\n')
		response = strings.TrimSpace(strings.ToLower(response))

		if response == "y" || response == "yes" {
			strategy := sync.ParseStrategy(cfg.SyncStrategy)

			// Create progress reporter
			var reporter sync.ProgressReporter
			if sync.ShouldShowProgress(quietFlag) {
				reporter = sync.NewInteractiveProgress(os.Stdout)
			} else {
				reporter = &sync.NoOpProgress{}
			}

			result, err := client.Sync(strategy, reporter)
			if err != nil {
				fmt.Fprintf(os.Stderr, "Error syncing: %v\n", err)
				os.Exit(1)
			}
			result.Display()
		}
	},
}

// opal sync status
var syncStatusCmd = &cobra.Command{
	Use:   "status",
	Short: "Show sync status",
	Long:  `Display current sync configuration and status`,
	Run: func(cmd *cobra.Command, args []string) {
		cfg, err := engine.GetConfig()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
			os.Exit(1)
		}

		if !cfg.SyncEnabled {
			fmt.Println("Sync is not configured.")
			fmt.Println("Run 'opal sync init' to configure sync.")
			return
		}

		fmt.Println("Sync Configuration")
		fmt.Println("━━━━━━━━━━━━━━━━━━")
		fmt.Printf("Enabled:        %v\n", cfg.SyncEnabled)
		fmt.Printf("URL:            %s\n", cfg.SyncURL)
		fmt.Printf("Client ID:      %s\n", cfg.SyncClientID)
		fmt.Printf("Strategy:       %s\n", cfg.SyncStrategy)
		fmt.Printf("Queue offline:  %v\n", cfg.SyncQueueOffline)

		// Check queue status
		queue, err := sync.NewQueue()
		if err == nil && queue.Size() > 0 {
			fmt.Printf("\n⚠️  %d changes queued for sync\n", queue.Size())
		}

		// Get last sync time
		db := engine.GetDB()
		if db != nil {
			var lastSync int64
			err := db.QueryRow("SELECT last_sync FROM sync_state WHERE client_id = ?", cfg.SyncClientID).Scan(&lastSync)
			if err == nil && lastSync > 0 {
				fmt.Printf("\nLast sync:      %s\n", formatTimestamp(lastSync))
			}
		}

		// Test connectivity
		fmt.Print("\nTesting connection... ")
		_ = sync.NewClient(cfg.SyncURL, cfg.SyncAPIKey, cfg.SyncClientID)
		// Simple connectivity test - we can't call testConnection directly, so we'll just show config
		fmt.Println("(run 'opal sync now' to test)")
	},
}

// opal sync now (default)
var syncNowCmd = &cobra.Command{
	Use:   "now",
	Short: "Sync with server now",
	Long:  `Perform bidirectional sync with the server`,
	Run: func(cmd *cobra.Command, args []string) {
		cfg, err := engine.GetConfig()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
			os.Exit(1)
		}

		if !cfg.SyncEnabled {
			fmt.Println("Sync is not configured.")
			fmt.Println("Run 'opal sync init' to configure sync.")
			os.Exit(1)
		}

		client := sync.NewClient(cfg.SyncURL, cfg.SyncAPIKey, cfg.SyncClientID)
		strategy := sync.ParseStrategy(cfg.SyncStrategy)

		// Create progress reporter
		var reporter sync.ProgressReporter
		if sync.ShouldShowProgress(quietFlag) {
			reporter = sync.NewInteractiveProgress(os.Stdout)
		} else {
			reporter = &sync.NoOpProgress{}
		}

		result, err := client.Sync(strategy, reporter)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
			os.Exit(1)
		}

		result.Display()
	},
}

// opal sync up
var syncUpCmd = &cobra.Command{
	Use:   "up",
	Short: "Push local changes to server",
	Long:  `Upload local changes to the server`,
	Run: func(cmd *cobra.Command, args []string) {
		cfg, err := engine.GetConfig()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
			os.Exit(1)
		}

		if !cfg.SyncEnabled {
			fmt.Println("Sync is not configured.")
			os.Exit(1)
		}

		client := sync.NewClient(cfg.SyncURL, cfg.SyncAPIKey, cfg.SyncClientID)

		// Get local changes
		lastSync := sync.GetLastSyncTime(cfg.SyncClientID)
		localChanges, err := sync.GetLocalChanges(lastSync)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error getting local changes: %v\n", err)
			os.Exit(1)
		}

		if len(localChanges) == 0 {
			fmt.Println("No local changes to push")
			return
		}

		fmt.Printf("Pushing %d changes...\n", len(localChanges))
		if err := client.PushChanges(localChanges); err != nil {
			fmt.Fprintf(os.Stderr, "Error pushing changes: %v\n", err)
			os.Exit(1)
		}

		fmt.Println("✓ Changes pushed successfully")
	},
}

// opal sync down
var syncDownCmd = &cobra.Command{
	Use:   "down",
	Short: "Pull server changes to local",
	Long:  `Download changes from the server`,
	Run: func(cmd *cobra.Command, args []string) {
		cfg, err := engine.GetConfig()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
			os.Exit(1)
		}

		if !cfg.SyncEnabled {
			fmt.Println("Sync is not configured.")
			os.Exit(1)
		}

		client := sync.NewClient(cfg.SyncURL, cfg.SyncAPIKey, cfg.SyncClientID)
		lastSync := sync.GetLastSyncTime(cfg.SyncClientID)

		changes, err := client.PullChanges(lastSync)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error pulling changes: %v\n", err)
			os.Exit(1)
		}

		if len(changes) == 0 {
			fmt.Println("No changes from server")
			return
		}

		// Parse changes into tasks
		tasks, err := client.ParseChanges(changes)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error parsing changes: %v\n", err)
			os.Exit(1)
		}

		// Apply each task locally
		var applied int
		for _, task := range tasks {
			if err := task.Save(); err != nil {
				fmt.Fprintf(os.Stderr, "Warning: failed to save task %s: %v\n", task.UUID, err)
				continue
			}

			// Mark as sync-originated to prevent feedback loop
			_ = engine.MarkChangeLogAsSync(task.UUID.String())

			// Sync tags
			savedTask, err := engine.GetTask(task.UUID)
			if err != nil {
				fmt.Fprintf(os.Stderr, "Warning: failed to reload task %s: %v\n", task.UUID, err)
				continue
			}

			currentTags, _ := savedTask.GetTags()
			currentSet := make(map[string]bool)
			for _, tag := range currentTags {
				currentSet[tag] = true
			}
			desiredSet := make(map[string]bool)
			for _, tag := range task.Tags {
				desiredSet[tag] = true
			}
			for tag := range currentSet {
				if !desiredSet[tag] {
					savedTask.RemoveTag(tag)
				}
			}
			for tag := range desiredSet {
				if !currentSet[tag] {
					savedTask.AddTag(tag)
				}
			}

			applied++
		}

		fmt.Printf("✓ Pulled %d changes, applied %d tasks from server\n", len(changes), applied)
	},
}

// opal sync log
var syncLogCmd = &cobra.Command{
	Use:   "log",
	Short: "Show conflict resolution log",
	Long:  `Display the log of sync conflicts and how they were resolved`,
	Run: func(cmd *cobra.Command, args []string) {
		logPath, err := engine.GetSyncConflictLogPath()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
			os.Exit(1)
		}
		data, err := os.ReadFile(logPath)
		if err != nil {
			if os.IsNotExist(err) {
				fmt.Println("No conflicts logged yet.")
				return
			}
			fmt.Fprintf(os.Stderr, "Error reading log: %v\n", err)
			os.Exit(1)
		}

		fmt.Print(string(data))
	},
}

// opal sync merge
var syncMergeCmd = &cobra.Command{
	Use:   "merge",
	Short: "Initial database merge",
	Long: `Merge local database with server database for first-time sync.

This is used when connecting an existing local database to a server for the first time.

Strategies:
  --prefer-local:  Upload all local tasks, merge server tasks
  --prefer-server: Download all server tasks, merge local tasks
  --smart:         Merge by UUID, add unique tasks from both sides (default)

Examples:
  opal sync merge
  opal sync merge --prefer-local
  opal sync merge --prefer-server`,
	Run: func(cmd *cobra.Command, args []string) {
		cfg, err := engine.GetConfig()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
			os.Exit(1)
		}

		if !cfg.SyncEnabled {
			fmt.Println("Sync is not configured.")
			fmt.Println("Run 'opal sync init' to configure sync.")
			os.Exit(1)
		}

		preferLocal, _ := cmd.Flags().GetBool("prefer-local")
		preferServer, _ := cmd.Flags().GetBool("prefer-server")

		strategy := sync.LastWriteWins // Default: smart merge
		if preferLocal {
			strategy = sync.ClientWins
		} else if preferServer {
			strategy = sync.ServerWins
		}

		fmt.Println("Performing initial merge...")
		fmt.Printf("Strategy: %s\n\n", sync.StrategyString(strategy))

		// Get all local tasks (not just recent changes)
		filter := engine.DefaultFilter()
		localTasks, err := engine.GetTasks(filter)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error getting local tasks: %v\n", err)
			os.Exit(1)
		}

		fmt.Printf("Found %d local tasks\n", len(localTasks))

		// Pull all changes from server
		client := sync.NewClient(cfg.SyncURL, cfg.SyncAPIKey, cfg.SyncClientID)
		changes, err := client.PullChanges(0) // Get all changes (since epoch)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error pulling from server: %v\n", err)
			os.Exit(1)
		}

		fmt.Printf("Found %d server changes\n", len(changes))

		// Parse server tasks
		// For initial merge, we'll do a full sync

		// Create progress reporter
		var reporter sync.ProgressReporter
		if sync.ShouldShowProgress(quietFlag) {
			reporter = sync.NewInteractiveProgress(os.Stdout)
		} else {
			reporter = &sync.NoOpProgress{}
		}

		result, err := client.Sync(strategy, reporter)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error during merge: %v\n", err)
			os.Exit(1)
		}

		fmt.Println("\n✓ Initial merge completed")
		result.Display()
	},
}

func init() {
	syncCmd.GroupID = "other"
	rootCmd.AddCommand(syncCmd)

	syncCmd.AddCommand(syncInitCmd)
	syncCmd.AddCommand(syncStatusCmd)
	syncCmd.AddCommand(syncNowCmd)
	syncCmd.AddCommand(syncUpCmd)
	syncCmd.AddCommand(syncDownCmd)
	syncCmd.AddCommand(syncLogCmd)
	syncCmd.AddCommand(syncMergeCmd)

	// Flags
	syncInitCmd.Flags().StringP("url", "u", "", "Server URL")
	syncInitCmd.Flags().StringP("key", "k", "", "API key")

	syncMergeCmd.Flags().Bool("prefer-local", false, "Prefer local database")
	syncMergeCmd.Flags().Bool("prefer-server", false, "Prefer server database")

	// Global sync flags
	syncCmd.PersistentFlags().BoolVarP(&quietFlag, "quiet", "q", false, "Suppress progress output")
}

func formatTimestamp(ts int64) string {
	t := time.Unix(ts, 0)
	now := time.Now()
	diff := now.Sub(t)

	switch {
	case diff < time.Minute:
		return "just now"
	case diff < time.Hour:
		m := int(diff.Minutes())
		if m == 1 {
			return "1 minute ago"
		}
		return fmt.Sprintf("%d minutes ago", m)
	case diff < 24*time.Hour:
		h := int(diff.Hours())
		if h == 1 {
			return "1 hour ago"
		}
		return fmt.Sprintf("%d hours ago", h)
	case diff < 7*24*time.Hour:
		d := int(diff.Hours() / 24)
		if d == 1 {
			return "yesterday"
		}
		return fmt.Sprintf("%d days ago", d)
	default:
		return t.Format("2006-01-02 15:04")
	}
}