// Package model holds the wire and domain types passed between layers.
package model

import (
	"encoding/json"
	"time"
)

// EventType is the Segment-compatible call kind.
type EventType string

const (
	EventTypeTrack    EventType = "track"
	EventTypeIdentify EventType = "identify"
	EventTypePage     EventType = "page"
	EventTypeGroup    EventType = "group"
	EventTypeAlias    EventType = "alias"
	EventTypeScreen   EventType = "screen"
)

// RawEvent is the parsed-but-not-yet-validated payload from a client.
// We keep Properties / Traits / Context as json.RawMessage so the handler can
// pass them through to the service untouched; flattening happens in service.
type RawEvent struct {
	Type        EventType       `json:"type"        validate:"required,oneof=track identify page group alias screen"`
	MessageID   string          `json:"messageId"   validate:"required,max=128"`
	AnonymousID string          `json:"anonymousId" validate:"max=128"`
	UserID      string          `json:"userId"      validate:"max=128"`
	GroupID     string          `json:"groupId"     validate:"max=128"`
	Event       string          `json:"event"       validate:"max=255"`
	Name        string          `json:"name"        validate:"max=255"`
	Category    string          `json:"category"    validate:"max=255"`
	Properties  json.RawMessage `json:"properties"`
	Traits      json.RawMessage `json:"traits"`
	Context     json.RawMessage `json:"context"`
	Timestamp   *time.Time      `json:"timestamp"`
	SentAt      *time.Time      `json:"sentAt"`
}

// BatchEnvelope is the body of /batch — Segment-compatible.
type BatchEnvelope struct {
	Batch    []RawEvent      `json:"batch" validate:"required,min=1,max=1000,dive"`
	SentAt   *time.Time      `json:"sentAt"`
	Context  json.RawMessage `json:"context"`
}

// IngestedEvent is the canonical record we push onto Kafka. Flat fields,
// timestamps already normalized, payload sanitized.
type IngestedEvent struct {
	WorkspaceID string                 `json:"workspace_id"`
	SourceID    string                 `json:"source_id"`
	MessageID   string                 `json:"message_id"`
	Type        EventType              `json:"type"`
	AnonymousID string                 `json:"anonymous_id,omitempty"`
	UserID      string                 `json:"user_id,omitempty"`
	GroupID     string                 `json:"group_id,omitempty"`
	Event       string                 `json:"event,omitempty"`
	Name        string                 `json:"name,omitempty"`
	Category    string                 `json:"category,omitempty"`
	Properties  map[string]any         `json:"properties,omitempty"`
	Traits      map[string]any         `json:"traits,omitempty"`
	Context     map[string]any         `json:"context,omitempty"`
	IP          string                 `json:"ip,omitempty"`
	UserAgent   string                 `json:"user_agent,omitempty"`

	Timestamp  time.Time `json:"timestamp"`
	SentAt     time.Time `json:"sent_at"`
	ReceivedAt time.Time `json:"received_at"`
}

// PartitionKey returns the key used for Kafka partitioning. We use
// anonymous_id to keep identity-stitching ordering per visitor.
func (e *IngestedEvent) PartitionKey() string {
	if e.AnonymousID != "" {
		return e.AnonymousID
	}
	if e.UserID != "" {
		return e.UserID
	}
	return e.MessageID
}