package store

import (
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/google/uuid"
)

func (m *Memory) ListMaintenancePolicies(cursor string, limit int) ([]*MaintenancePolicy, string, bool, error) {
	if limit <= 0 {
		limit = 50
	}
	m.mu.RLock()
	defer m.mu.RUnlock()
	all := make([]*MaintenancePolicy, 0, len(m.maintenancePolicies))
	for _, p := range m.maintenancePolicies {
		all = append(all, p)
	}
	sort.Slice(all, func(i, j int) bool {
		if all[i].CreatedAt.Equal(all[j].CreatedAt) {
			return all[i].ID > all[j].ID
		}
		return all[i].CreatedAt.After(all[j].CreatedAt)
	})
	off := parseMaintCursor(cursor)
	end := off + limit
	next := ""
	hasMore := false
	if end > len(all) {
		end = len(all)
	} else if end < len(all) {
		hasMore = true
		next = formatMaintCursor(end)
	}
	if off >= len(all) {
		return nil, "", false, nil
	}
	out := make([]*MaintenancePolicy, end-off)
	copy(out, all[off:end])
	return out, next, hasMore, nil
}

func (m *Memory) GetMaintenancePolicy(id string) (*MaintenancePolicy, error) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	p, ok := m.maintenancePolicies[id]
	if !ok {
		return nil, ErrNotFound
	}
	return cloneMaintenancePolicy(p), nil
}

func (m *Memory) CreateMaintenancePolicy(in *MaintenancePolicy) (*MaintenancePolicy, error) {
	if in == nil {
		return nil, ErrInvalidInput
	}
	vacuum := in.VacuumStrategy
	if vacuum == "" {
		vacuum = VacuumStrategyNone
	}
	if err := ValidateMaintenancePolicyInput(in.Name, in.TableName, vacuum, in.Schedule); err != nil {
		return nil, err
	}
	m.mu.Lock()
	defer m.mu.Unlock()
	now := time.Now().UTC()
	id := uuid.NewString()
	p := &MaintenancePolicy{
		ID:                 id,
		Name:               strings.TrimSpace(in.Name),
		TableName:          strings.TrimSpace(in.TableName),
		Condition:          NormalizeMaintenancePolicyCondition(in.Condition),
		RetentionPeriodSec: in.RetentionPeriodSec,
		MaxRows:            in.MaxRows,
		VacuumStrategy:     vacuum,
		Schedule:           strings.TrimSpace(in.Schedule),
		Enabled:            in.Enabled,
		DryRunEnabled:      in.DryRunEnabled,
		CreatedAt:          now,
		UpdatedAt:          now,
	}
	m.maintenancePolicies[id] = p
	return cloneMaintenancePolicy(p), nil
}

func (m *Memory) UpdateMaintenancePolicy(id string, patch *MaintenancePolicyPatch) (*MaintenancePolicy, error) {
	if patch == nil {
		return nil, ErrInvalidInput
	}
	m.mu.Lock()
	defer m.mu.Unlock()
	p, ok := m.maintenancePolicies[id]
	if !ok {
		return nil, ErrNotFound
	}
	if patch.Name != nil {
		p.Name = strings.TrimSpace(*patch.Name)
	}
	if patch.TableName != nil {
		p.TableName = strings.TrimSpace(*patch.TableName)
	}
	if patch.Condition != nil {
		p.Condition = NormalizeMaintenancePolicyCondition(*patch.Condition)
	}
	if patch.RetentionPeriodSec != nil {
		p.RetentionPeriodSec = patch.RetentionPeriodSec
	}
	if patch.MaxRows != nil {
		p.MaxRows = patch.MaxRows
	}
	if patch.VacuumStrategy != nil {
		if !ValidVacuumStrategy(*patch.VacuumStrategy) {
			return nil, ErrInvalidInput
		}
		p.VacuumStrategy = strings.TrimSpace(*patch.VacuumStrategy)
	}
	if patch.Schedule != nil {
		p.Schedule = strings.TrimSpace(*patch.Schedule)
	}
	if patch.Enabled != nil {
		p.Enabled = *patch.Enabled
	}
	if patch.DryRunEnabled != nil {
		p.DryRunEnabled = *patch.DryRunEnabled
	}
	if err := ValidateMaintenancePolicyInput(p.Name, p.TableName, p.VacuumStrategy, p.Schedule); err != nil {
		return nil, err
	}
	p.UpdatedAt = time.Now().UTC()
	return cloneMaintenancePolicy(p), nil
}

func (m *Memory) DeleteMaintenancePolicy(id string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if _, ok := m.maintenancePolicies[id]; !ok {
		return ErrNotFound
	}
	delete(m.maintenancePolicies, id)
	return nil
}

func (m *Memory) TouchMaintenancePolicyRun(id, status, errMsg string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	p, ok := m.maintenancePolicies[id]
	if !ok {
		return ErrNotFound
	}
	now := time.Now().UTC()
	p.LastRunAt = &now
	p.LastStatus = status
	p.LastError = errMsg
	p.UpdatedAt = now
	return nil
}

func (m *Memory) AppendMaintenancePolicyConfigAudit(actor, policyID, action string, before, after map[string]any) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	row := &MaintenancePolicyConfigAudit{
		ID:          uuid.NewString(),
		PolicyID:    policyID,
		ActorPrefix: strings.TrimSpace(actor),
		Action:      action,
		Before:      before,
		After:       after,
		CreatedAt:   time.Now().UTC(),
	}
	m.maintConfigAudit = append(m.maintConfigAudit, row)
	return nil
}

func (m *Memory) ListMaintenancePolicyConfigAudit(cursor string, limit int) ([]*MaintenancePolicyConfigAudit, string, bool, error) {
	if limit <= 0 {
		limit = 50
	}
	m.mu.RLock()
	defer m.mu.RUnlock()
	all := append([]*MaintenancePolicyConfigAudit(nil), m.maintConfigAudit...)
	sort.Slice(all, func(i, j int) bool {
		if all[i].CreatedAt.Equal(all[j].CreatedAt) {
			return all[i].ID > all[j].ID
		}
		return all[i].CreatedAt.After(all[j].CreatedAt)
	})
	off := parseMaintCursor(cursor)
	end := off + limit
	next := ""
	hasMore := false
	if end > len(all) {
		end = len(all)
	} else if end < len(all) {
		hasMore = true
		next = formatMaintCursor(end)
	}
	if off >= len(all) {
		return nil, "", false, nil
	}
	out := make([]*MaintenancePolicyConfigAudit, end-off)
	copy(out, all[off:end])
	return out, next, hasMore, nil
}

func cloneMaintenancePolicy(p *MaintenancePolicy) *MaintenancePolicy {
	if p == nil {
		return nil
	}
	cp := *p
	if p.RetentionPeriodSec != nil {
		v := *p.RetentionPeriodSec
		cp.RetentionPeriodSec = &v
	}
	if p.MaxRows != nil {
		v := *p.MaxRows
		cp.MaxRows = &v
	}
	if p.LastRunAt != nil {
		t := *p.LastRunAt
		cp.LastRunAt = &t
	}
	return &cp
}

func parseMaintCursor(cursor string) int {
	if cursor == "" {
		return 0
	}
	var off int
	for _, r := range cursor {
		if r < '0' || r > '9' {
			return 0
		}
		off = off*10 + int(r-'0')
	}
	return off
}

func formatMaintCursor(off int) string {
	return strconv.Itoa(off)
}