package bus

import (
	"context"
	"encoding/json"
	"strings"

	"github.com/google/uuid"
)

// MediaFile represents an inbound media file with its MIME type.
// Used throughout the media pipeline to preserve content type from channel download to storage.
type MediaFile struct {
	Path     string `json:"path"`
	MimeType string `json:"mime_type,omitempty"` // e.g. "application/pdf", "image/jpeg"
	Filename string `json:"filename,omitempty"`  // original user-provided filename, e.g. "Báo cáo Q4.pdf"; empty → UUID fallback in persistMedia
	Caption  string `json:"caption,omitempty"`   // optional outbound caption attached to this file
}

// InboundMessage represents a message received from a channel (Telegram, Discord, etc.)
type InboundMessage struct {
	Channel                    string            `json:"channel"`
	SenderID                   string            `json:"sender_id"`
	ChatID                     string            `json:"chat_id"`
	Content                    string            `json:"content"`
	Media                      []MediaFile       `json:"media,omitempty"`
	SessionKey                 string            `json:"session_key"`                            // deprecated: gateway builds canonical key
	PeerKind                   string            `json:"peer_kind,omitempty"`                    // "direct" or "group" (used for session key)
	TenantID                   uuid.UUID         `json:"tenant_id,omitempty"`                    // tenant scope from channel instance
	AgentID                    string            `json:"agent_id,omitempty"`                     // target agent (for multi-agent routing)
	UserID                     string            `json:"user_id,omitempty"`                      // external user ID for per-user scoping (memory, bootstrap)
	HistoryLimit               int               `json:"history_limit,omitempty"`                // max turns to keep in context (0=unlimited, from channel config)
	ToolAllow                  []string          `json:"tool_allow,omitempty"`                   // per-group tool allow list (nil = no restriction)
	TelegramManagerPermissions []string          `json:"telegram_manager_permissions,omitempty"` // hidden Telegram management permission groups for this inbound run
	Metadata                   map[string]string `json:"metadata,omitempty"`
}

// OutboundMessage represents a message to be sent to a channel.
type OutboundMessage struct {
	Channel          string            `json:"channel"`
	ChatID           string            `json:"chat_id"`
	Content          string            `json:"content"`
	Media            []MediaAttachment `json:"media,omitempty"`              // optional media attachments
	Metadata         map[string]string `json:"metadata,omitempty"`           // channel-specific metadata
	TenantID         uuid.UUID         `json:"tenant_id,omitempty"`          // tenant scope for per-tenant TTS
	AgentID          uuid.UUID         `json:"agent_id,omitempty"`           // agent scope for per-agent TTS voice override
	AgentOtherConfig []byte            `json:"agent_other_config,omitempty"` // agent's other_config for TTS voice/model
}

// Metadata keys on OutboundMessage.Metadata used to track the origin chat of
// a cross-target forward (message tool, forward=true). The outbound dispatch
// consumer runs async with no path back to the tool call that queued it, so
// these let it notify the ORIGIN chat if delivery to the forward target
// actually fails — otherwise a bad target (e.g. a display name instead of a
// real chat ID) fails silently downstream while the tool already reported
// success back to the model.
const (
	MetaForwardOriginChannel = "forward_origin_channel"
	MetaForwardOriginChatID  = "forward_origin_chat_id"
)

// MediaAttachment represents a media file to be sent with a message.
type MediaAttachment struct {
	URL         string `json:"url"`                    // file path or URL
	ContentType string `json:"content_type,omitempty"` // MIME type (e.g. "image/jpeg", "video/mp4")
	Caption     string `json:"caption,omitempty"`      // optional caption for media
}

// Event represents a server-side event to broadcast to WebSocket clients.
type Event struct {
	Name     string    `json:"name"` // event name (e.g. "agent", "chat", "health")
	Payload  any       `json:"payload,omitempty"`
	TenantID uuid.UUID `json:"-"` // tenant scope for event filtering (not serialized to clients)
}

// Cache invalidation kind constants.
const (
	CacheKindAgent            = "agent"
	CacheKindBootstrap        = "bootstrap"
	CacheKindSkills           = "skills"
	CacheKindCron             = "cron"
	CacheKindChannelInstances = "channel_instances"
	CacheKindBuiltinTools     = "builtin_tools"
	CacheKindTeam             = "team"
	CacheKindUserWorkspace    = "user_workspace"
	CacheKindSkillGrants      = "skill_grants"
	CacheKindMCP              = "mcp"
	CacheKindProvider         = "provider"
	CacheKindAPIKeys          = "api_keys"
	CacheKindHeartbeat        = "heartbeat"
	CacheKindConfigPerms      = "config_perms"
	CacheKindTenantUsers      = "tenant_users"
	CacheKindAgentAccess      = "agent_access"
	CacheKindTeamAccess       = "team_access"
	CacheKindTenants          = "tenants"
)

// Topic constants for msgBus.Subscribe() / Broadcast().
const (
	TopicCacheBootstrap        = "cache:bootstrap"
	TopicCacheAgent            = "cache:agent"
	TopicCacheSkills           = "cache:skills"
	TopicCacheCron             = "cache:cron"
	TopicCacheBuiltinTools     = "cache:builtin_tools"
	TopicCacheTeam             = "cache:team"
	TopicCacheUserWorkspace    = "cache:user_workspace"
	TopicCacheChannelInstances = "cache:channel_instances"
	TopicCacheSkillGrants      = "cache:skill_grants"
	TopicCacheMCP              = "cache:mcp"
	TopicCacheProvider         = "cache:provider"
	TopicCacheHeartbeat        = "cache:heartbeat"
	TopicCacheConfigPerms      = "cache:config_perms"
	TopicAudit                 = "audit"
	TopicTeamTaskAudit         = "team-task-audit"
	TopicChannelStreaming      = "channel-streaming"
	TopicConfigChanged         = "config:changed"
	TopicSystemConfigChanged   = "system_config:changed"
	TopicPairingRevoked        = "pairing:revoked"
	TopicAgentStatusChanged    = "agent:status_changed"
	TopicAgentDeleted          = "agent:deleted"
)

// EventPairingRevoked is the event name broadcast when a paired device is revoked.
const EventPairingRevoked = "pairing.revoked"

// PairingRevokedPayload identifies the revoked device.
type PairingRevokedPayload struct {
	SenderID string `json:"sender_id"`
	Channel  string `json:"channel"`
}

// EventAgentStatusChanged is broadcast when an agent's status changes (e.g., active → inactive).
const EventAgentStatusChanged = "agent.status_changed"

// AgentStatusChangedPayload carries agent status transition info for cascade operations.
type AgentStatusChangedPayload struct {
	AgentID   string `json:"agent_id"`
	OldStatus string `json:"old_status"`
	NewStatus string `json:"new_status"`
}

// AgentDeletedPayload carries agent deletion info for async cleanup (e.g. orphaned provider removal).
type AgentDeletedPayload struct {
	AgentKey string    `json:"agent_key"`
	Provider string    `json:"provider,omitempty"` // provider name for orphan cleanup
	TenantID uuid.UUID `json:"tenant_id,omitempty"`
}

// AuditEventPayload carries audit log data emitted by handlers.
// A single subscriber persists these to the activity_logs table.
type AuditEventPayload struct {
	ActorType  string          `json:"actor_type"`
	ActorID    string          `json:"actor_id"`
	Action     string          `json:"action"`
	EntityType string          `json:"entity_type"`
	EntityID   string          `json:"entity_id"`
	IPAddress  string          `json:"ip_address,omitempty"`
	Details    json.RawMessage `json:"details,omitempty"`
	TenantID   uuid.UUID       `json:"tenant_id,omitempty"` // for async subscriber tenant scoping
}

// CacheInvalidatePayload signals cache layers to evict stale entries.
// Used with protocol.EventCacheInvalidate events. Events are delivered
// in-process via MessageBus and never marshaled to the wire, so the json
// tags are documentation-only (and omitempty on uuid.UUID is a no-op
// because uuid.UUID is [16]byte — all-zero arrays don't count as empty).
type CacheInvalidatePayload struct {
	Kind string `json:"kind"` // CacheKind* constants
	Key  string `json:"key"`  // agent_key, agent_id, etc. Empty = invalidate all
	// TenantID scopes the invalidation to a single tenant. uuid.Nil means
	// global (master admin action) — subscribers treat it as "invalidate all".
	TenantID uuid.UUID `json:"tenant_id"`
}

// MessageHandler handles an inbound message from a specific channel.
type MessageHandler func(InboundMessage) error

// EventHandler handles a broadcast event.
type EventHandler func(Event)

// EventPublisher abstracts event broadcast + subscription.
// Used by gateway server and agents to decouple from concrete MessageBus.
type EventPublisher interface {
	Subscribe(id string, handler EventHandler)
	Unsubscribe(id string)
	Broadcast(event Event)
}

// MessageRouter abstracts inbound/outbound message routing between channels and the agent runtime.
type MessageRouter interface {
	PublishInbound(msg InboundMessage)
	ConsumeInbound(ctx context.Context) (InboundMessage, bool)
	PublishOutbound(msg OutboundMessage)
	SubscribeOutbound(ctx context.Context) (OutboundMessage, bool)
}

// IsInternalSender returns true if the senderID belongs to an internal system
// component (not a real channel user). These should not be stored as contacts
// and must be rejected by per-user permission checks in group contexts (#915).
func IsInternalSender(senderID string) bool {
	return strings.HasPrefix(senderID, "system:") ||
		strings.HasPrefix(senderID, "notification:") ||
		strings.HasPrefix(senderID, "teammate:") ||
		strings.HasPrefix(senderID, "ticker:") ||
		strings.HasPrefix(senderID, "subagent:") ||
		senderID == "session_send_tool"
}