package logging

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"sync"
	"time"

	"chorus/pkg/shhh"
	"github.com/libp2p/go-libp2p/core/peer"
)

// Logger interface for basic logging operations
type Logger interface {
	Info(msg string, args ...interface{})
	Warn(msg string, args ...interface{})
	Error(msg string, args ...interface{})
}

// HypercoreLog represents a simplified Hypercore-inspired distributed log
type HypercoreLog struct {
	entries []LogEntry
	mutex   sync.RWMutex
	peerID  peer.ID

	// Verification chain
	headHash string

	// Replication
	replicators map[peer.ID]*Replicator

	redactor *shhh.Sentinel
}

// LogEntry represents a single entry in the distributed log
type LogEntry struct {
	Index     uint64                 `json:"index"`
	Timestamp time.Time              `json:"timestamp"`
	Author    string                 `json:"author"`    // Peer ID of the author
	Type      LogType                `json:"type"`      // Type of log entry
	Data      map[string]interface{} `json:"data"`      // Log data
	Hash      string                 `json:"hash"`      // Hash of this entry
	PrevHash  string                 `json:"prev_hash"` // Hash of previous entry
	Signature string                 `json:"signature"` // Digital signature (simplified)
}

// LogType represents different types of log entries
type LogType string

const (
	// Bzzz coordination logs
	TaskAnnounced LogType = "task_announced"
	TaskClaimed   LogType = "task_claimed"
	TaskProgress  LogType = "task_progress"
	TaskCompleted LogType = "task_completed"
	TaskFailed    LogType = "task_failed"

	// HMMM meta-discussion logs
	PlanProposed      LogType = "plan_proposed"
	ObjectionRaised   LogType = "objection_raised"
	Collaboration     LogType = "collaboration"
	ConsensusReached  LogType = "consensus_reached"
	Escalation        LogType = "escalation"
	TaskHelpRequested LogType = "task_help_requested"
	TaskHelpOffered   LogType = "task_help_offered"
	TaskHelpReceived  LogType = "task_help_received"

	// System logs
	PeerJoined      LogType = "peer_joined"
	PeerLeft        LogType = "peer_left"
	CapabilityBcast LogType = "capability_broadcast"
	NetworkEvent    LogType = "network_event"
)

// Replicator handles log replication with other peers
type Replicator struct {
	peerID        peer.ID
	lastSyncIndex uint64
	connected     bool
}

// NewHypercoreLog creates a new distributed log for a peer
func NewHypercoreLog(peerID peer.ID) *HypercoreLog {
	return &HypercoreLog{
		entries:     make([]LogEntry, 0),
		peerID:      peerID,
		headHash:    "",
		replicators: make(map[peer.ID]*Replicator),
	}
}

// SetRedactor wires the SHHH sentinel so log payloads are sanitized before persistence.
func (h *HypercoreLog) SetRedactor(redactor *shhh.Sentinel) {
	h.mutex.Lock()
	defer h.mutex.Unlock()
	h.redactor = redactor
}

// AppendString is a convenience method for string log types (to match interface)
func (h *HypercoreLog) AppendString(logType string, data map[string]interface{}) error {
	_, err := h.Append(LogType(logType), data)
	return err
}

// Append adds a new entry to the log
func (h *HypercoreLog) Append(logType LogType, data map[string]interface{}) (*LogEntry, error) {
	h.mutex.Lock()
	defer h.mutex.Unlock()

	index := uint64(len(h.entries))

	sanitized := h.redactData(logType, data)

	entry := LogEntry{
		Index:     index,
		Timestamp: time.Now(),
		Author:    h.peerID.String(),
		Type:      logType,
		Data:      sanitized,
		PrevHash:  h.headHash,
	}

	// Calculate hash
	entryHash, err := h.calculateEntryHash(entry)
	if err != nil {
		return nil, fmt.Errorf("failed to calculate entry hash: %w", err)
	}
	entry.Hash = entryHash

	// Add simple signature (in production, use proper cryptographic signatures)
	entry.Signature = h.createSignature(entry)

	// Append to log
	h.entries = append(h.entries, entry)
	h.headHash = entryHash

	fmt.Printf("📝 Log entry appended: %s [%d] by %s\n",
		logType, index, h.peerID.ShortString())

	// Trigger replication to connected peers
	go h.replicateEntry(entry)

	return &entry, nil
}

// Get retrieves a log entry by index
func (h *HypercoreLog) Get(index uint64) (*LogEntry, error) {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	if index >= uint64(len(h.entries)) {
		return nil, fmt.Errorf("entry %d not found", index)
	}

	return &h.entries[index], nil
}

// Length returns the number of entries in the log
func (h *HypercoreLog) Length() uint64 {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	return uint64(len(h.entries))
}

// GetRange retrieves a range of log entries
func (h *HypercoreLog) GetRange(start, end uint64) ([]LogEntry, error) {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	if start >= uint64(len(h.entries)) {
		return nil, fmt.Errorf("start index %d out of range", start)
	}

	if end > uint64(len(h.entries)) {
		end = uint64(len(h.entries))
	}

	if start > end {
		return nil, fmt.Errorf("invalid range: start %d > end %d", start, end)
	}

	result := make([]LogEntry, end-start)
	copy(result, h.entries[start:end])

	return result, nil
}

// GetEntriesByType retrieves all entries of a specific type
func (h *HypercoreLog) GetEntriesByType(logType LogType) ([]LogEntry, error) {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	var result []LogEntry
	for _, entry := range h.entries {
		if entry.Type == logType {
			result = append(result, entry)
		}
	}

	return result, nil
}

// GetEntriesByAuthor retrieves all entries by a specific author
func (h *HypercoreLog) GetEntriesByAuthor(author string) ([]LogEntry, error) {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	var result []LogEntry
	for _, entry := range h.entries {
		if entry.Author == author {
			result = append(result, entry)
		}
	}

	return result, nil
}

// GetRecentEntries retrieves the most recent N entries from the log
func (h *HypercoreLog) GetRecentEntries(count int) ([]LogEntry, error) {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	totalEntries := len(h.entries)
	if count <= 0 || totalEntries == 0 {
		return []LogEntry{}, nil
	}

	start := 0
	if totalEntries > count {
		start = totalEntries - count
	}

	result := make([]LogEntry, totalEntries-start)
	copy(result, h.entries[start:])

	return result, nil
}

// GetEntriesSince retrieves all entries since a given index
func (h *HypercoreLog) GetEntriesSince(sinceIndex uint64) ([]LogEntry, error) {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	if sinceIndex >= uint64(len(h.entries)) {
		return []LogEntry{}, nil
	}

	result := make([]LogEntry, len(h.entries)-int(sinceIndex))
	copy(result, h.entries[sinceIndex:])

	return result, nil
}

// VerifyIntegrity verifies the integrity of the log chain
func (h *HypercoreLog) VerifyIntegrity() error {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	var prevHash string
	for i, entry := range h.entries {
		// Verify previous hash link
		if entry.PrevHash != prevHash {
			return fmt.Errorf("integrity error at entry %d: prev_hash mismatch", i)
		}

		// Verify entry hash
		calculatedHash, err := h.calculateEntryHash(entry)
		if err != nil {
			return fmt.Errorf("failed to calculate hash for entry %d: %w", i, err)
		}

		if entry.Hash != calculatedHash {
			return fmt.Errorf("integrity error at entry %d: hash mismatch", i)
		}

		prevHash = entry.Hash
	}

	return nil
}

// AddReplicator adds a peer for log replication
func (h *HypercoreLog) AddReplicator(peerID peer.ID) {
	h.mutex.Lock()
	defer h.mutex.Unlock()

	h.replicators[peerID] = &Replicator{
		peerID:        peerID,
		lastSyncIndex: 0,
		connected:     true,
	}

	fmt.Printf("🔄 Added replicator: %s\n", peerID.ShortString())
}

// RemoveReplicator removes a peer from replication
func (h *HypercoreLog) RemoveReplicator(peerID peer.ID) {
	h.mutex.Lock()
	defer h.mutex.Unlock()

	delete(h.replicators, peerID)
	fmt.Printf("🔄 Removed replicator: %s\n", peerID.ShortString())
}

// replicateEntry sends a new entry to all connected replicators
func (h *HypercoreLog) replicateEntry(entry LogEntry) {
	h.mutex.RLock()
	replicators := make([]*Replicator, 0, len(h.replicators))
	for _, replicator := range h.replicators {
		if replicator.connected {
			replicators = append(replicators, replicator)
		}
	}
	h.mutex.RUnlock()

	for _, replicator := range replicators {
		// In a real implementation, this would send the entry over the network
		fmt.Printf("🔄 Replicating entry %d to %s\n",
			entry.Index, replicator.peerID.ShortString())
	}
}

// calculateEntryHash calculates the hash of a log entry
func (h *HypercoreLog) calculateEntryHash(entry LogEntry) (string, error) {
	// Create a copy without the hash and signature for calculation
	entryForHash := LogEntry{
		Index:     entry.Index,
		Timestamp: entry.Timestamp,
		Author:    entry.Author,
		Type:      entry.Type,
		Data:      entry.Data,
		PrevHash:  entry.PrevHash,
	}

	entryBytes, err := json.Marshal(entryForHash)
	if err != nil {
		return "", err
	}

	hash := sha256.Sum256(entryBytes)
	return hex.EncodeToString(hash[:]), nil
}

func (h *HypercoreLog) redactData(logType LogType, data map[string]interface{}) map[string]interface{} {
	cloned := cloneLogMap(data)
	if cloned == nil {
		return nil
	}
	if h.redactor != nil {
		labels := map[string]string{
			"source":   "hypercore",
			"log_type": string(logType),
		}
		h.redactor.RedactMapWithLabels(context.Background(), cloned, labels)
	}
	return cloned
}

func cloneLogMap(in map[string]interface{}) map[string]interface{} {
	if in == nil {
		return nil
	}
	out := make(map[string]interface{}, len(in))
	for k, v := range in {
		out[k] = cloneLogValue(v)
	}
	return out
}

// @goal: CHORUS-REQ-001 - Fix duplicate type case compilation error
// WHY: Go 1.18+ treats interface{} and any as identical types, causing duplicate case errors
func cloneLogValue(v interface{}) interface{} {
	switch tv := v.(type) {
	case map[string]any:
		// @goal: CHORUS-REQ-001 - Convert any to interface{} for cloneLogMap compatibility
		converted := make(map[string]interface{}, len(tv))
		for k, val := range tv {
			converted[k] = val
		}
		return cloneLogMap(converted)
	case []any:
		converted := make([]interface{}, len(tv))
		for i, val := range tv {
			converted[i] = cloneLogValue(val)
		}
		return converted
	case []string:
		return append([]string(nil), tv...)
	default:
		return tv
	}
}

func cloneLogSlice(in []interface{}) []interface{} {
	out := make([]interface{}, len(in))
	for i, val := range in {
		out[i] = cloneLogValue(val)
	}
	return out
}

// createSignature creates a simplified signature for the entry
func (h *HypercoreLog) createSignature(entry LogEntry) string {
	// In production, this would use proper cryptographic signatures
	// For now, we use a simple hash-based signature
	signatureData := fmt.Sprintf("%s:%s:%d", h.peerID.String(), entry.Hash, entry.Index)
	hash := sha256.Sum256([]byte(signatureData))
	return hex.EncodeToString(hash[:])[:16] // Shortened for display
}

// GetStats returns statistics about the log
func (h *HypercoreLog) GetStats() map[string]interface{} {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	typeCount := make(map[LogType]int)
	authorCount := make(map[string]int)

	for _, entry := range h.entries {
		typeCount[entry.Type]++
		authorCount[entry.Author]++
	}

	return map[string]interface{}{
		"total_entries":     len(h.entries),
		"head_hash":         h.headHash,
		"replicators":       len(h.replicators),
		"entries_by_type":   typeCount,
		"entries_by_author": authorCount,
		"peer_id":           h.peerID.String(),
	}
}