package fleet

import (
	"context"
	"crypto/rand"
	"database/sql"
	"encoding/hex"
	"encoding/json"
	"time"

	"github.com/google/uuid"
)

// LOTLAttempt is one triple-onion deploy audit row.
type LOTLAttempt struct {
	ID           string    `json:"id"`
	HostID       string    `json:"host_id"`
	Tier         int       `json:"tier"`
	Phase        string    `json:"phase"`
	Status       string    `json:"status"`
	Error        string    `json:"error,omitempty"`
	MetadataJSON string    `json:"metadata_json,omitempty"`
	CreatedAt    time.Time `json:"created_at"`
}

// DB exposes the underlying SQLite connection.
func (s *Store) DB() *sql.DB {
	return s.db
}

// LogLOTL records a triple-onion phase attempt.
func (s *Store) LogLOTL(ctx context.Context, hostID string, tier int, phase, status, errMsg, metadata string) error {
	if s == nil {
		return nil
	}
	if metadata == "" {
		metadata = "{}"
	}
	_, err := s.db.ExecContext(ctx, `
		INSERT INTO lotl_attempts (id, host_id, tier, phase, status, error, metadata_json)
		VALUES (?, ?, ?, ?, ?, ?, ?)`,
		uuid.NewString(), hostID, tier, phase, status, errMsg, metadata)
	return err
}

// ListLOTL returns recent attempts for a host (newest first).
func (s *Store) ListLOTL(ctx context.Context, hostID string, limit int) ([]LOTLAttempt, error) {
	if limit <= 0 {
		limit = 50
	}
	rows, err := s.db.QueryContext(ctx, `
		SELECT id, host_id, tier, phase, status, COALESCE(error,''), metadata_json, created_at
		FROM lotl_attempts WHERE host_id = ?
		ORDER BY created_at DESC LIMIT ?`, hostID, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []LOTLAttempt
	for rows.Next() {
		var a LOTLAttempt
		var created string
		if err := rows.Scan(&a.ID, &a.HostID, &a.Tier, &a.Phase, &a.Status, &a.Error, &a.MetadataJSON, &created); err != nil {
			return nil, err
		}
		a.CreatedAt, _ = time.Parse("2006-01-02 15:04:05", created)
		out = append(out, a)
	}
	return out, rows.Err()
}

const atlasFailureThreshold = 3
const atlasImmuneHours = 24

// ShouldSkipTier checks failure atlas immunity for phenotype+tier.
func (s *Store) ShouldSkipTier(ctx context.Context, phenotype string, tier int) (bool, error) {
	if phenotype == "" || s == nil {
		return false, nil
	}
	var count int
	var immuneUntil sqlNullTime
	err := s.db.QueryRowContext(ctx, `
		SELECT failure_count, immune_until FROM failure_atlas
		WHERE phenotype = ? AND tier = ?`, phenotype, tier).Scan(&count, &immuneUntil)
	if err != nil {
		return false, nil
	}
	if immuneUntil.Valid && time.Now().Before(immuneUntil.Time) {
		return true, nil
	}
	return false, nil
}

// RecordFailure increments failure atlas for phenotype+tier.
func (s *Store) RecordFailure(ctx context.Context, phenotype string, tier int) error {
	if phenotype == "" || s == nil {
		return nil
	}
	var count int
	_ = s.db.QueryRowContext(ctx, `
		SELECT failure_count FROM failure_atlas WHERE phenotype = ? AND tier = ?`,
		phenotype, tier).Scan(&count)
	count++

	immuneUntil := ""
	if count >= atlasFailureThreshold {
		until := time.Now().Add(atlasImmuneHours * time.Hour)
		immuneUntil = until.Format("2006-01-02 15:04:05")
	}

	_, err := s.db.ExecContext(ctx, `
		INSERT INTO failure_atlas (id, phenotype, tier, failure_count, immune_until, updated_at)
		VALUES (?, ?, ?, ?, ?, datetime('now'))
		ON CONFLICT(phenotype, tier) DO UPDATE SET
			failure_count = excluded.failure_count,
			immune_until = excluded.immune_until,
			updated_at = datetime('now')`,
		randomHexID(), phenotype, tier, count, nullIfEmpty(immuneUntil))
	return err
}

// RecordWin records a successful tier and updates adaptive order wins.
func (s *Store) RecordWin(ctx context.Context, phenotype string, tier int) error {
	if phenotype == "" || s == nil {
		return nil
	}
	order, _ := s.GetAdaptiveOrder(ctx, phenotype)
	order = promoteTier(order, tier)
	b, _ := json.Marshal(order)
	_, err := s.db.ExecContext(ctx, `
		INSERT INTO phenotype_tier_orders (phenotype, tier_order_json, wins, updated_at)
		VALUES (?, ?, 1, datetime('now'))
		ON CONFLICT(phenotype) DO UPDATE SET
			tier_order_json = excluded.tier_order_json,
			wins = wins + 1,
			updated_at = datetime('now')`,
		phenotype, string(b))
	return err
}

func promoteTier(order []int, tier int) []int {
	out := []int{tier}
	for _, t := range order {
		if t != tier {
			out = append(out, t)
		}
	}
	for _, t := range defaultOrderInts() {
		found := false
		for _, x := range out {
			if x == t {
				found = true
				break
			}
		}
		if !found {
			out = append(out, t)
		}
	}
	return out
}

// GetAdaptiveOrder returns learned tier order or defaults.
func (s *Store) GetAdaptiveOrder(ctx context.Context, phenotype string) ([]int, error) {
	if phenotype != "" {
		var raw string
		err := s.db.QueryRowContext(ctx, `
			SELECT tier_order_json FROM phenotype_tier_orders WHERE phenotype = ?`, phenotype).
			Scan(&raw)
		if err == nil && raw != "" && raw != "[]" {
			var order []int
			if json.Unmarshal([]byte(raw), &order) == nil && len(order) > 0 {
				return order, nil
			}
		}
	}
	return defaultOrderInts(), nil
}

func defaultOrderInts() []int {
	order := DefaultTierOrder()
	out := make([]int, len(order))
	for i := range order {
		out[i] = i + 1
	}
	return out
}

// SetHostPhenotype persists recon-derived fingerprint on a host.
func (s *Store) SetHostPhenotype(ctx context.Context, hostID, reconJSON, phenotype string) error {
	_, err := s.db.ExecContext(ctx, `
		UPDATE hosts SET phenotype = ?, fingerprint = COALESCE(NULLIF(fingerprint,''), ?),
			updated_at = datetime('now') WHERE id = ?`,
		phenotype, reconJSON, hostID)
	return err
}

// HostHashrate returns current hashrate for earn-before-burn gate.
func (s *Store) HostHashrate(ctx context.Context, hostID string) (float64, error) {
	var hr float64
	err := s.db.QueryRowContext(ctx, `SELECT hashrate FROM hosts WHERE id = ?`, hostID).Scan(&hr)
	return hr, err
}

// SiblingHosts lists other enrolled hosts sharing a phenotype.
func (s *Store) SiblingHosts(ctx context.Context, hostID, phenotype string) ([]string, error) {
	if phenotype == "" {
		return nil, nil
	}
	rows, err := s.db.QueryContext(ctx, `
		SELECT id FROM hosts WHERE phenotype = ? AND id != ? AND status != 'offline'`,
		phenotype, hostID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var ids []string
	for rows.Next() {
		var id string
		if err := rows.Scan(&id); err != nil {
			return nil, err
		}
		ids = append(ids, id)
	}
	return ids, rows.Err()
}

func randomHexID() string {
	b := make([]byte, 16)
	_, _ = rand.Read(b)
	return hex.EncodeToString(b)
}