package channel

import "github.com/gochat/gochat/internal/model"

// ChannelFacebook represents a Facebook Messenger channel.
// Reference: Chatwoot app/models/channel/facebook_page.rb
//
// Chatwoot's ChannelFacebook (Channel::FacebookPage) model attributes:
//   - account_id: FK to Account
//   - page_id: Facebook Page ID
//   - page_access_token: Long-lived Page access token
//   - page_name: Display name of the FB Page
//   - reauthorization_required: Flag when token expires
//
// gochat enhancements beyond Chatwoot:
//   - instagram_business_account_id: Optional link to IG account for cross-channel
//   - app_id: FB App ID for webhook verification
//   - webhook_verify_token: Token for FB webhook subscription verification
type ChannelFacebook struct {
	model.Base

	// Account foreign key
	AccountID uint `gorm:"index;not null" json:"account_id"`

	// Inbox foreign key — links to the Inbox that wraps this channel
	InboxID uint `gorm:"not null;uniqueIndex" json:"inbox_id"`

	// Facebook Page ID — identifies the FB Page for Messenger
	PageID string `gorm:"size:255;not null" json:"page_id"`

	// Long-lived Page access token for Graph API calls
	// Requires pages_messaging permission for Messenger
	PageAccessToken string `gorm:"size:512;not null" json:"page_access_token"`

	// Display name of the Facebook Page
	PageName string `gorm:"size:255" json:"page_name,omitempty"`

	// FB App ID — used for webhook verification and API calls
	AppID string `gorm:"size:255" json:"app_id,omitempty"`

	// Webhook verify token — used during FB webhook subscription
	// Reference: Chatwoot doesn't store this; GoChat adds for verification
	WebhookVerifyToken string `gorm:"size:255" json:"webhook_verify_token,omitempty"`

	// Instagram Business Account ID — links to IG account for cross-channel
	// When set, this FB Page also manages Instagram DMs
	// Reference: FB Graph API /me?fields=instagram_business_account
	InstagramBusinessAccountID string `gorm:"size:255" json:"instagram_business_account_id,omitempty"`

	// Tracks when the Page token needs reauthorization
	ReauthorizationRequired bool `gorm:"default:false" json:"reauthorization_required"`
}

func (ChannelFacebook) TableName() string { return "channel_facebook_pages" }

// GetChannelBase returns the base channel fields for polymorphic access.
func (c *ChannelFacebook) GetChannelBase() ChannelBase {
	return ChannelBase{
		AccountID:   c.AccountID,
		InboxID:     c.InboxID,
		ChannelType: "facebook",
	}
}

// GetChannelType returns the channel type identifier.
func (c *ChannelFacebook) GetChannelType() string { return "facebook" }