package tracker

import (
	"encoding/json"
	"fmt"
	"time"

	"github.com/sirupsen/logrus"
	bolt "go.etcd.io/bbolt"
)

const (
	StatusPending    = "pending"
	StatusInProgress = "in_progress"
	StatusCompleted  = "completed"
	StatusFailed     = "failed"
)

type MigrationJob struct {
	ID             string    `json:"id"`
	SourceName     string    `json:"source_name"`
	DestName       string    `json:"dest_name"`
	Status         string    `json:"status"`
	StartTime      time.Time `json:"start_time"`
	EndTime        time.Time `json:"end_time,omitempty"`
	TotalFiles     int64     `json:"total_files"`
	CompletedFiles int64     `json:"completed_files"`
	ErrorMessage   string    `json:"error_message,omitempty"`
}

type FileEntry struct {
	Path         string    `json:"path"`
	Size         int64     `json:"size"`
	Status       string    `json:"status"`
	TransferTime time.Time `json:"transfer_time,omitempty"`
	ErrorMessage string    `json:"error_message,omitempty"`
}

type Tracker struct {
	db *bolt.DB
}

var (
	jobsBucket  = []byte("jobs")
	filesBucket = []byte("files")
)

// NewTracker creates a new tracker instance
func NewTracker(dbPath string) (*Tracker, error) {
	db, err := bolt.Open(dbPath, 0600, &bolt.Options{Timeout: 1 * time.Second})
	if err != nil {
		return nil, fmt.Errorf("failed to open database: %w", err)
	}

	// Create buckets if they don't exist
	err = db.Update(func(tx *bolt.Tx) error {
		if _, err := tx.CreateBucketIfNotExists(jobsBucket); err != nil {
			return err
		}
		if _, err := tx.CreateBucketIfNotExists(filesBucket); err != nil {
			return err
		}
		return nil
	})
	if err != nil {
		db.Close()
		return nil, fmt.Errorf("failed to create buckets: %w", err)
	}

	return &Tracker{db: db}, nil
}

// Close closes the database connection
func (t *Tracker) Close() error {
	return t.db.Close()
}

// CreateJob creates a new migration job
func (t *Tracker) CreateJob(job *MigrationJob) error {
	return t.db.Update(func(tx *bolt.Tx) error {
		b := tx.Bucket(jobsBucket)
		data, err := json.Marshal(job)
		if err != nil {
			return err
		}
		return b.Put([]byte(job.ID), data)
	})
}

// UpdateJob updates an existing migration job
func (t *Tracker) UpdateJob(job *MigrationJob) error {
	return t.CreateJob(job) // Same as create for now
}

// GetJob retrieves a migration job by ID
func (t *Tracker) GetJob(jobID string) (*MigrationJob, error) {
	var job MigrationJob
	err := t.db.View(func(tx *bolt.Tx) error {
		b := tx.Bucket(jobsBucket)
		data := b.Get([]byte(jobID))
		if data == nil {
			return fmt.Errorf("job not found")
		}
		return json.Unmarshal(data, &job)
	})
	return &job, err
}

// MarkFileCompleted marks a file as completed
func (t *Tracker) MarkFileCompleted(jobID, filePath string, size int64) error {
	file := &FileEntry{
		Path:         filePath,
		Size:         size,
		Status:       StatusCompleted,
		TransferTime: time.Now(),
	}

	return t.db.Update(func(tx *bolt.Tx) error {
		b := tx.Bucket(filesBucket)
		key := fmt.Sprintf("%s:%s", jobID, filePath)
		data, err := json.Marshal(file)
		if err != nil {
			return err
		}
		return b.Put([]byte(key), data)
	})
}

// IsFileCompleted checks if a file has been completed
func (t *Tracker) IsFileCompleted(jobID, filePath string) bool {
	var completed bool
	t.db.View(func(tx *bolt.Tx) error {
		b := tx.Bucket(filesBucket)
		key := fmt.Sprintf("%s:%s", jobID, filePath)
		data := b.Get([]byte(key))
		if data != nil {
			var file FileEntry
			if err := json.Unmarshal(data, &file); err == nil {
				completed = file.Status == StatusCompleted
			}
		}
		return nil
	})
	return completed
}

// GetCompletedFiles returns the count of completed files for a job
func (t *Tracker) GetCompletedFiles(jobID string) int64 {
	var count int64
	t.db.View(func(tx *bolt.Tx) error {
		b := tx.Bucket(filesBucket)
		c := b.Cursor()
		prefix := []byte(jobID + ":")

		for k, v := c.Seek(prefix); k != nil && len(k) > len(prefix) && string(k[:len(prefix)]) == string(prefix); k, v = c.Next() {
			var file FileEntry
			if err := json.Unmarshal(v, &file); err == nil && file.Status == StatusCompleted {
				count++
			}
		}
		return nil
	})
	return count
}

// LogProgress logs the current progress
func (t *Tracker) LogProgress(jobID string) {
	job, err := t.GetJob(jobID)
	if err != nil {
		logrus.Errorf("Failed to get job: %v", err)
		return
	}

	completed := t.GetCompletedFiles(jobID)
	if job.TotalFiles > 0 {
		percentage := float64(completed) / float64(job.TotalFiles) * 100
		logrus.Infof("Progress: %d/%d files (%.2f%%)", completed, job.TotalFiles, percentage)
	} else {
		logrus.Infof("Progress: %d files completed", completed)
	}
}