package store

import (
	"strings"
	"sync"
	"time"
)

func (m *Memory) GetModulePrefixSnapshot(tenantID, moduleID string) (*ModulePrefixSnapshot, bool, error) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	key := moduleSnapshotKey(tenantID, moduleID)
	snap, ok := m.moduleSnapshots[key]
	if !ok || snap == nil {
		return nil, false, nil
	}
	cp := make([]PrefixRow, len(snap.Prefixes))
	copy(cp, snap.Prefixes)
	return &ModulePrefixSnapshot{
		InputHash:   snap.InputHash,
		CollectedAt: snap.CollectedAt,
		Prefixes:    cp,
	}, true, nil
}

func (m *Memory) SetModulePrefixSnapshot(tenantID, moduleID, inputHash string, prefixes []PrefixRow) error {
	if strings.TrimSpace(tenantID) == "" || strings.TrimSpace(moduleID) == "" || strings.TrimSpace(inputHash) == "" {
		return ErrInvalidInput
	}
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.moduleSnapshots == nil {
		m.moduleSnapshots = make(map[string]*moduleSnapshotRec)
	}
	cp := make([]PrefixRow, len(prefixes))
	copy(cp, prefixes)
	key := moduleSnapshotKey(tenantID, moduleID)
	m.moduleSnapshots[key] = &moduleSnapshotRec{
		InputHash:   inputHash,
		CollectedAt: time.Now().UTC(),
		Prefixes:    cp,
	}
	return nil
}

func (m *Memory) DeleteModulePrefixSnapshot(tenantID, moduleID string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.moduleSnapshots != nil {
		delete(m.moduleSnapshots, moduleSnapshotKey(tenantID, moduleID))
	}
	return nil
}

func (m *Memory) SetModuleInputHash(tenantID, moduleID, hash string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	mod, ok := m.modules[moduleID]
	if !ok || mod.DeletedAt != nil {
		return ErrNotFound
	}
	if mod.TenantID != tenantID {
		return ErrTenantScope
	}
	mod.InputHash = strings.TrimSpace(hash)
	return nil
}

func (m *Memory) LockModuleSnapshot(tenantID, moduleID string) func() {
	key := moduleSnapshotKey(tenantID, moduleID)
	v, _ := m.snapshotLocks.LoadOrStore(key, &sync.Mutex{})
	mu := v.(*sync.Mutex)
	mu.Lock()
	return func() { mu.Unlock() }
}

type moduleSnapshotRec struct {
	InputHash   string
	CollectedAt time.Time
	Prefixes    []PrefixRow
}

func moduleSnapshotKey(tenantID, moduleID string) string {
	return strings.TrimSpace(tenantID) + "\x00" + strings.TrimSpace(moduleID)
}