package cache

import (
	"fmt"
	"log/slog"
	"sync"
	"time"

	"github.com/sparetimecoders/goamqp"
	"gitlab.com/unboundsoftware/eventsourced/eventsourced"

	"gitea.unbound.se/unboundsoftware/schemas/domain"
	"gitea.unbound.se/unboundsoftware/schemas/graph/model"
	"gitea.unbound.se/unboundsoftware/schemas/hash"
)

type Cache struct {
	mu            sync.RWMutex
	organizations map[string]domain.Organization
	users         map[string][]string
	apiKeys       map[string]domain.APIKey // keyed by organizationId-name
	services      map[string]map[string]map[string]struct{}
	subGraphs     map[string]string
	lastUpdate    map[string]string
	mergedSDLs    map[string]*mergedSDLEntry
	schemaUpdates map[string]*model.SchemaUpdate
	logger        *slog.Logger
}

// mergedSDLEntry holds a precomputed merged SDL together with the lastUpdate
// id it was computed against, so stale entries can be detected on read.
type mergedSDLEntry struct {
	ID        string
	SDL       string
	SubGraphs []*model.SubGraph
}

func (c *Cache) OrganizationByAPIKey(apiKey string) *domain.Organization {
	c.mu.RLock()
	defer c.mu.RUnlock()

	// Find the API key by comparing hashes
	for _, key := range c.apiKeys {
		if hash.CompareAPIKey(key.Key, apiKey) {
			org, exists := c.organizations[key.OrganizationId]
			if !exists {
				return nil
			}
			return &org
		}
	}
	return nil
}

func (c *Cache) OrganizationsByUser(sub string) []domain.Organization {
	c.mu.RLock()
	defer c.mu.RUnlock()

	orgIds := c.users[sub]
	orgs := make([]domain.Organization, len(orgIds))
	for i, id := range orgIds {
		orgs[i] = c.organizations[id]
	}
	return orgs
}

func (c *Cache) AllOrganizations() []domain.Organization {
	c.mu.RLock()
	defer c.mu.RUnlock()

	orgs := make([]domain.Organization, 0, len(c.organizations))
	for _, org := range c.organizations {
		orgs = append(orgs, org)
	}
	return orgs
}

func (c *Cache) ApiKeyByKey(key string) *domain.APIKey {
	c.mu.RLock()
	defer c.mu.RUnlock()

	// Find the API key by comparing hashes
	for _, apiKey := range c.apiKeys {
		if hash.CompareAPIKey(apiKey.Key, key) {
			return &apiKey
		}
	}
	return nil
}

func (c *Cache) Services(orgId, ref, lastUpdate string) ([]string, string) {
	c.mu.RLock()
	defer c.mu.RUnlock()

	key := refKey(orgId, ref)
	var services []string
	if lastUpdate == "" || c.lastUpdate[key] > lastUpdate {
		for k := range c.services[orgId][ref] {
			services = append(services, k)
		}
	}
	return services, c.lastUpdate[key]
}

func (c *Cache) SubGraphId(orgId, ref, service string) string {
	c.mu.RLock()
	defer c.mu.RUnlock()

	return c.subGraphs[subGraphKey(orgId, ref, service)]
}

func (c *Cache) Update(msg any, _ goamqp.Headers) (any, error) {
	c.mu.Lock()
	defer c.mu.Unlock()

	switch m := msg.(type) {
	case *domain.OrganizationAdded:
		o := domain.Organization{
			BaseAggregate: eventsourced.BaseAggregateFromString(m.ID.String()),
		}
		m.UpdateOrganization(&o)
		c.organizations[m.ID.String()] = o
		c.addUser(m.Initiator, o)
		c.logger.With("org_id", m.ID.String(), "event", "OrganizationAdded").Debug("cache updated")
	case *domain.UserAddedToOrganization:
		org, exists := c.organizations[m.ID.String()]
		if exists {
			m.UpdateOrganization(&org)
			c.organizations[m.ID.String()] = org
			c.addUser(m.UserId, org)
			c.logger.With("org_id", m.ID.String(), "user_id", m.UserId, "event", "UserAddedToOrganization").Debug("cache updated")
		} else {
			c.logger.With("org_id", m.ID.String(), "event", "UserAddedToOrganization").Warn("organization not found in cache")
		}
	case *domain.APIKeyAdded:
		key := domain.APIKey{
			Name:           m.Name,
			OrganizationId: m.OrganizationId,
			Key:            m.Key, // This is now the hashed key
			Refs:           m.Refs,
			Read:           m.Read,
			Publish:        m.Publish,
			CreatedBy:      m.Initiator,
			CreatedAt:      m.When(),
		}
		// Use composite key: organizationId-name
		c.apiKeys[apiKeyId(m.OrganizationId, m.Name)] = key
		org := c.organizations[m.OrganizationId]
		org.APIKeys = append(org.APIKeys, key)
		c.organizations[m.OrganizationId] = org
		c.logger.With("org_id", m.OrganizationId, "key_name", m.Name, "event", "APIKeyAdded").Debug("cache updated")
	case *domain.APIKeyRemoved:
		orgId := m.ID.String()
		org, exists := c.organizations[orgId]
		if exists {
			// Remove from organization's API keys list
			for i, key := range org.APIKeys {
				if key.Name == m.KeyName {
					org.APIKeys = append(org.APIKeys[:i], org.APIKeys[i+1:]...)
					break
				}
			}
			c.organizations[orgId] = org
			// Remove from apiKeys map
			delete(c.apiKeys, apiKeyId(orgId, m.KeyName))
			c.logger.With("org_id", orgId, "key_name", m.KeyName, "event", "APIKeyRemoved").Debug("cache updated")
		} else {
			c.logger.With("org_id", orgId, "event", "APIKeyRemoved").Warn("organization not found in cache")
		}
	case *domain.OrganizationRemoved:
		orgId := m.ID.String()
		org, exists := c.organizations[orgId]
		if exists {
			// Remove all API keys for this organization
			for _, key := range org.APIKeys {
				delete(c.apiKeys, apiKeyId(orgId, key.Name))
			}
			// Remove organization from all users
			for userId, userOrgs := range c.users {
				for i, userOrgId := range userOrgs {
					if userOrgId == orgId {
						c.users[userId] = append(userOrgs[:i], userOrgs[i+1:]...)
						break
					}
				}
				// If user has no more organizations, remove from map
				if len(c.users[userId]) == 0 {
					delete(c.users, userId)
				}
			}
			// Remove services for this organization
			if refs, exists := c.services[orgId]; exists {
				for ref := range refs {
					// Remove all subgraphs for this org/ref combination
					for service := range refs[ref] {
						delete(c.subGraphs, subGraphKey(orgId, ref, service))
					}
					// Remove cached results for this org/ref
					rk := refKey(orgId, ref)
					delete(c.lastUpdate, rk)
					delete(c.mergedSDLs, rk)
					delete(c.schemaUpdates, rk)
				}
				delete(c.services, orgId)
			}
			// Remove organization
			delete(c.organizations, orgId)
			c.logger.With("org_id", orgId, "event", "OrganizationRemoved").Debug("cache updated")
		} else {
			c.logger.With("org_id", orgId, "event", "OrganizationRemoved").Warn("organization not found in cache")
		}
	case *domain.SubGraphUpdated:
		c.updateSubGraph(m.OrganizationId, m.Ref, m.ID.String(), m.Service, m.Time)
		c.logger.With("org_id", m.OrganizationId, "ref", m.Ref, "service", m.Service, "event", "SubGraphUpdated").Debug("cache updated")
	case *domain.Organization:
		c.organizations[m.ID.String()] = *m
		c.addUser(m.CreatedBy, *m)
		for _, k := range m.APIKeys {
			// Use composite key: organizationId-name
			c.apiKeys[apiKeyId(k.OrganizationId, k.Name)] = k
		}
		c.logger.With("org_id", m.ID.String(), "event", "Organization aggregate loaded").Debug("cache updated")
	case *domain.SubGraph:
		c.updateSubGraph(m.OrganizationId, m.Ref, m.ID.String(), m.Service, m.ChangedAt)
		c.logger.With("org_id", m.OrganizationId, "ref", m.Ref, "service", m.Service, "event", "SubGraph aggregate loaded").Debug("cache updated")
	default:
		c.logger.With("msg", msg).Warn("unexpected message received")
	}
	return nil, nil
}

func (c *Cache) updateSubGraph(orgId string, ref string, subGraphId string, service string, updated time.Time) {
	if _, exists := c.services[orgId]; !exists {
		c.services[orgId] = make(map[string]map[string]struct{})
	}
	if _, exists := c.services[orgId][ref]; !exists {
		c.services[orgId][ref] = make(map[string]struct{})
	}
	c.services[orgId][ref][subGraphId] = struct{}{}
	c.subGraphs[subGraphKey(orgId, ref, service)] = subGraphId
	c.lastUpdate[refKey(orgId, ref)] = updated.Format(time.RFC3339Nano)
}

func (c *Cache) addUser(sub string, organization domain.Organization) {
	user, exists := c.users[sub]
	orgId := organization.ID.String()
	if !exists {
		c.users[sub] = []string{orgId}
		return
	}

	// Check if organization already exists for this user
	for _, id := range user {
		if id == orgId {
			return // Already exists, no need to add
		}
	}

	c.users[sub] = append(user, orgId)
}

func New(logger *slog.Logger) *Cache {
	return &Cache{
		organizations: make(map[string]domain.Organization),
		users:         make(map[string][]string),
		apiKeys:       make(map[string]domain.APIKey),
		services:      make(map[string]map[string]map[string]struct{}),
		subGraphs:     make(map[string]string),
		lastUpdate:    make(map[string]string),
		mergedSDLs:    make(map[string]*mergedSDLEntry),
		schemaUpdates: make(map[string]*model.SchemaUpdate),
		logger:        logger,
	}
}

// GetMergedSDL returns the cached merged SDL for (orgId, ref) if it was
// computed against the current lastUpdate. Returns nil when missing or stale.
func (c *Cache) GetMergedSDL(orgId, ref string) *mergedSDLEntry {
	c.mu.RLock()
	defer c.mu.RUnlock()

	key := refKey(orgId, ref)
	entry := c.mergedSDLs[key]
	if entry == nil || entry.ID != c.lastUpdate[key] {
		return nil
	}
	return entry
}

// MergedSDLEntry exposes the cached merged SDL fields to callers.
func (e *mergedSDLEntry) Unpack() (id, sdl string, subGraphs []*model.SubGraph) {
	return e.ID, e.SDL, e.SubGraphs
}

// SetMergedSDL stores a precomputed merged SDL for (orgId, ref). The entry
// is only retained while c.lastUpdate[key] matches id; subsequent updates
// invalidate it implicitly via the version mismatch in GetMergedSDL.
func (c *Cache) SetMergedSDL(orgId, ref, id, sdl string, subGraphs []*model.SubGraph) {
	c.mu.Lock()
	defer c.mu.Unlock()

	c.mergedSDLs[refKey(orgId, ref)] = &mergedSDLEntry{
		ID:        id,
		SDL:       sdl,
		SubGraphs: subGraphs,
	}
}

// GetSchemaUpdate returns the cached SchemaUpdate (subgraphs + cosmo router
// config) for (orgId, ref) when its id matches the current lastUpdate.
// Returns nil when missing or stale.
func (c *Cache) GetSchemaUpdate(orgId, ref string) *model.SchemaUpdate {
	c.mu.RLock()
	defer c.mu.RUnlock()

	key := refKey(orgId, ref)
	upd := c.schemaUpdates[key]
	if upd == nil || upd.ID != c.lastUpdate[key] {
		return nil
	}
	return upd
}

// SetSchemaUpdate stores a precomputed SchemaUpdate for (orgId, ref).
func (c *Cache) SetSchemaUpdate(orgId, ref string, update *model.SchemaUpdate) {
	c.mu.Lock()
	defer c.mu.Unlock()

	c.schemaUpdates[refKey(orgId, ref)] = update
}

func refKey(orgId string, ref string) string {
	return fmt.Sprintf("%s<->%s", orgId, ref)
}

func subGraphKey(orgId string, ref string, service string) string {
	return fmt.Sprintf("%s<->%s<->%s", orgId, ref, service)
}

func apiKeyId(orgId string, name string) string {
	return fmt.Sprintf("%s<->%s", orgId, name)
}