package pds

import (
	"context"
	"fmt"

	"atcr.io/pkg/atproto"
	"atcr.io/pkg/hold/quota"
	lexutil "github.com/bluesky-social/indigo/lex/util"
	"github.com/bluesky-social/indigo/repo"
)

// CreateLayerRecord creates a new layer record in the hold's PDS
// Returns the rkey and CID of the created record
func (p *HoldPDS) CreateLayerRecord(ctx context.Context, record *atproto.LayerRecord) (string, string, error) {
	// Validate record
	if record.Type != atproto.LayerCollection {
		return "", "", fmt.Errorf("invalid record type: %s", record.Type)
	}

	if record.Digest == "" {
		return "", "", fmt.Errorf("digest is required")
	}

	if record.Size <= 0 {
		return "", "", fmt.Errorf("size must be positive")
	}

	// Create record with auto-generated TID rkey
	rkey, recordCID, err := p.repomgr.CreateRecord(
		ctx,
		p.uid,
		atproto.LayerCollection,
		record,
	)

	if err != nil {
		return "", "", fmt.Errorf("failed to create layer record: %w", err)
	}

	return rkey, recordCID.String(), nil
}

// GetLayerRecord retrieves a specific layer record by rkey
// Note: This is a simplified implementation. For production, you may need to pass the CID
func (p *HoldPDS) GetLayerRecord(ctx context.Context, rkey string) (*atproto.LayerRecord, error) {
	// For now, we don't implement this as it's not needed for the manifest post feature
	// Full implementation would require querying the carstore with a specific CID
	return nil, fmt.Errorf("GetLayerRecord not yet implemented - use via XRPC listRecords instead")
}

// DeleteLayerRecord deletes a layer record by rkey
// This deletes from both the repo (MST) and the records index
func (p *HoldPDS) DeleteLayerRecord(ctx context.Context, rkey string) error {
	// Delete from repo (MST)
	if err := p.repomgr.DeleteRecord(ctx, p.uid, atproto.LayerCollection, rkey); err != nil {
		return fmt.Errorf("failed to delete from repo: %w", err)
	}

	// Delete from index
	if p.recordsIndex != nil {
		if err := p.recordsIndex.DeleteRecord(atproto.LayerCollection, rkey); err != nil {
			// Log but don't fail - index will resync on backfill
			fmt.Printf("Warning: failed to delete from records index: %v\n", err)
		}
	}

	return nil
}

// ListLayerRecords lists layer records with pagination
// Returns records, next cursor (empty if no more), and error
// Note: This is a simplified implementation. For production, consider adding filters
// (by repository, user, digest, etc.) and proper pagination
func (p *HoldPDS) ListLayerRecords(ctx context.Context, limit int, cursor string) ([]*atproto.LayerRecord, string, error) {
	// For now, return empty list - full implementation would query the carstore
	// This would require iterating over records in the collection and filtering
	// In practice, layer records are mainly for analytics and Bluesky posts,
	// not for runtime queries
	return nil, "", fmt.Errorf("ListLayerRecords not yet implemented")
}

// QuotaStats represents storage quota information for a user
type QuotaStats struct {
	UserDID     string `json:"userDid"`
	UniqueBlobs int    `json:"uniqueBlobs"`
	TotalSize   int64  `json:"totalSize"`
	Limit       *int64 `json:"limit,omitempty"` // nil = unlimited
	Tier        string `json:"tier,omitempty"`  // quota tier (e.g., 'deckhand', 'bosun', 'quartermaster')
}

// GetQuotaForUser calculates storage quota for a specific user.
// Uses SQL aggregation over the denormalized digest/size columns in the records index.
func (p *HoldPDS) GetQuotaForUser(ctx context.Context, userDID string) (*QuotaStats, error) {
	if p.recordsIndex == nil {
		return nil, fmt.Errorf("records index not available")
	}

	uniqueBlobs, totalSize, err := p.recordsIndex.QuotaForDID(atproto.LayerCollection, userDID)
	if err != nil {
		return nil, fmt.Errorf("failed to query quota: %w", err)
	}

	return &QuotaStats{
		UserDID:     userDID,
		UniqueBlobs: uniqueBlobs,
		TotalSize:   totalSize,
	}, nil
}

// GetAllUserQuotas returns quota stats for all users in a single SQL query.
// Used by admin endpoints to avoid N+1 per-user quota lookups.
func (p *HoldPDS) GetAllUserQuotas(ctx context.Context) (map[string]*QuotaStats, error) {
	if p.recordsIndex == nil {
		return nil, fmt.Errorf("records index not available")
	}

	quotas, err := p.recordsIndex.QuotasByDID(atproto.LayerCollection)
	if err != nil {
		return nil, fmt.Errorf("failed to query all quotas: %w", err)
	}

	result := make(map[string]*QuotaStats, len(quotas))
	for did, q := range quotas {
		result[did] = &QuotaStats{
			UserDID:     did,
			UniqueBlobs: q.UniqueBlobs,
			TotalSize:   q.TotalSize,
		}
	}
	return result, nil
}

// GetQuotaForUserWithTier calculates quota with tier-aware limits
// It returns the base quota stats plus the tier limit and tier name.
// Captain (owner) always has unlimited quota.
func (p *HoldPDS) GetQuotaForUserWithTier(ctx context.Context, userDID string, quotaMgr *quota.Manager) (*QuotaStats, error) {
	// Get base stats
	stats, err := p.GetQuotaForUser(ctx, userDID)
	if err != nil {
		return nil, err
	}

	// If quota manager is nil or disabled, return unlimited
	if quotaMgr == nil || !quotaMgr.IsEnabled() {
		return stats, nil
	}

	// Check if user is captain (owner) - always unlimited
	_, captain, err := p.GetCaptainRecord(ctx)
	if err == nil && captain.Owner == userDID {
		stats.Tier = "owner"
		// Limit remains nil (unlimited)
		return stats, nil
	}

	// Get crew record to find tier
	crewTier := p.getCrewTier(ctx, userDID)

	// Resolve limit from quota manager
	stats.Limit = quotaMgr.GetTierLimit(crewTier)
	stats.Tier = quotaMgr.GetTierName(crewTier)

	return stats, nil
}

// getCrewTier returns the tier for a crew member, or empty string if not found
func (p *HoldPDS) getCrewTier(ctx context.Context, userDID string) string {
	crewMembers, err := p.ListCrewMembers(ctx)
	if err != nil {
		return ""
	}

	for _, member := range crewMembers {
		if member.Record.Member == userDID {
			return member.Record.Tier
		}
	}

	return ""
}

// ListLayerRecordsForUser returns all layer records uploaded by a specific user
// Used for GDPR data export to return all layers a user has pushed to this hold
func (p *HoldPDS) ListLayerRecordsForUser(ctx context.Context, userDID string) ([]*atproto.LayerRecord, error) {
	if p.recordsIndex == nil {
		return nil, fmt.Errorf("records index not available")
	}

	// Get session for reading record data
	session, err := p.carstore.ReadOnlySession(p.uid)
	if err != nil {
		return nil, fmt.Errorf("failed to create session: %w", err)
	}

	head, err := p.carstore.GetUserRepoHead(ctx, p.uid)
	if err != nil {
		return nil, fmt.Errorf("failed to get repo head: %w", err)
	}

	if !head.Defined() {
		// Empty repo - return empty list
		return []*atproto.LayerRecord{}, nil
	}

	repoHandle, err := repo.OpenRepo(ctx, session, head)
	if err != nil {
		return nil, fmt.Errorf("failed to open repo: %w", err)
	}

	var records []*atproto.LayerRecord

	// Iterate layer records for this user via the index (filtered by DID in SQL)
	cursor := ""
	batchSize := 1000

	for {
		indexRecords, nextCursor, err := p.recordsIndex.ListRecordsByDID(atproto.LayerCollection, userDID, batchSize, cursor)
		if err != nil {
			return nil, fmt.Errorf("failed to list layer records: %w", err)
		}

		for _, rec := range indexRecords {
			recordPath := rec.Collection + "/" + rec.Rkey

			_, recBytes, err := repoHandle.GetRecordBytes(ctx, recordPath)
			if err != nil {
				continue
			}

			recordValue, err := lexutil.CborDecodeValue(*recBytes)
			if err != nil {
				continue
			}

			layerRecord, ok := recordValue.(*atproto.LayerRecord)
			if !ok {
				continue
			}

			records = append(records, layerRecord)
		}

		if nextCursor == "" {
			break
		}
		cursor = nextCursor
	}

	if records == nil {
		records = []*atproto.LayerRecord{}
	}

	return records, nil
}