<?php
/**
 * ConvoHub API gateway. Every HTTP call to ConvoHub goes through this class.
 *
 * @package convohub
 */

defined( 'ABSPATH' ) || exit;

/**
 * Thin client for the ConvoHub (Chatwoot-based) REST API.
 *
 * Auth is the `api_access_token` header (the access token ConvoHub returned when the connection key was exchanged). Account-scoped endpoints live under
 * `/api/v1/accounts/:account_id`.
 */
class ConvoHub_API {

	/**
	 * API access token.
	 *
	 * @var string
	 */
	private $token;

	/**
	 * Account ID.
	 *
	 * @var int
	 */
	private $account_id;

	/**
	 * Constructor.
	 *
	 * @param string $token      API access token.
	 * @param int    $account_id Account ID, 0 when not chosen yet.
	 */
	public function __construct( $token, $account_id = 0 ) {
		$this->token      = $token;
		$this->account_id = (int) $account_id;
	}

	/**
	 * Builds a client from the saved settings.
	 *
	 * @return ConvoHub_API
	 */
	public static function from_settings() {
		$settings = ConvoHub_Settings::get();
		return new self( $settings['api_token'], $settings['account_id'] );
	}

	/**
	 * The signed-in user and every account the token can access.
	 *
	 * @return array|WP_Error
	 */
	public function profile() {
		return $this->request( 'GET', '/api/v1/profile' );
	}

	/**
	 * The configured account.
	 *
	 * @return array|WP_Error
	 */
	public function account() {
		return $this->account_request( 'GET', '' );
	}

	/**
	 * All inboxes of the account.
	 *
	 * @return array|WP_Error List of inboxes.
	 */
	public function inboxes() {
		$data = $this->account_request( 'GET', '/inboxes' );
		return is_wp_error( $data ) ? $data : (array) ( $data['payload'] ?? array() );
	}

	/**
	 * Creates a website (web widget) inbox.
	 *
	 * @param string $name        Inbox name.
	 * @param string $website_url Site URL.
	 * @return array|WP_Error The created inbox.
	 */
	public function create_web_widget_inbox( $name, $website_url ) {
		return $this->account_request(
			'POST',
			'/inboxes',
			array(
				'name'    => $name,
				'channel' => array(
					'type'        => 'web_widget',
					'website_url' => $website_url,
				),
			)
		);
	}

	/**
	 * Creates an API-channel inbox (used to receive website leads).
	 *
	 * @param string $name Inbox name.
	 * @return array|WP_Error The created inbox.
	 */
	public function create_api_inbox( $name ) {
		return $this->account_request(
			'POST',
			'/inboxes',
			array(
				'name'    => $name,
				'channel' => array( 'type' => 'api' ),
			)
		);
	}

	/**
	 * Creates (or finds) the contact and opens a conversation with the lead's message in one call.
	 * ConvoHub matches an existing contact by identifier, then email, then phone number.
	 *
	 * @param int    $inbox_id          API-channel inbox ID.
	 * @param array  $contact           Keys: name, email, phone_number.
	 * @param string $content           First message, sent as the contact.
	 * @param array  $custom_attributes Conversation custom attributes.
	 * @return array|WP_Error The created conversation.
	 */
	public function create_lead_conversation( $inbox_id, array $contact, $content, array $custom_attributes ) {
		return $this->account_request(
			'POST',
			'/conversations',
			array(
				'inbox_id'          => (int) $inbox_id,
				'contact'           => $contact,
				'message'           => array(
					'content'      => $content,
					'message_type' => 'incoming',
				),
				'custom_attributes' => $custom_attributes,
			)
		);
	}

	/**
	 * Updates channel attributes of an inbox (for example `allowed_domains`).
	 *
	 * @param int   $inbox_id Inbox ID.
	 * @param array $channel  Channel attributes.
	 * @return array|WP_Error The updated inbox.
	 */
	public function update_inbox_channel( $inbox_id, array $channel ) {
		return $this->account_request( 'PATCH', '/inboxes/' . absint( $inbox_id ), array( 'channel' => $channel ) );
	}

	/**
	 * Sends an email through ConvoHub as a new conversation of an email inbox.
	 *
	 * ConvoHub takes the subject of an email from the conversation (`additional_attributes.mail_subject`), reads
	 * `content` as plain text and sends `email_html_content` as the HTML part. The Developer API has no fields for
	 * either, so an email is created here instead: the contact is found or created in the same request. Each call is
	 * a new conversation with its own subject, unless the inbox is locked to a single conversation per contact, in
	 * which case ConvoHub keeps the first subject and adds "Re:".
	 *
	 * @param int    $inbox_id Email inbox ID.
	 * @param array  $contact  Keys: email, name, identifier, custom_attributes.
	 * @param string $subject  Subject, already rendered, plain text.
	 * @param string $text     Plain-text version of the email. Never empty: ConvoHub ignores the HTML of an empty message.
	 * @param string $html     The HTML body, as it is to be delivered.
	 * @param array  $options  `to_emails`, `cc_emails`, `bcc_emails` (comma-separated).
	 * @return array|WP_Error `conversation_id` (the number shown in ConvoHub) and `message_id` (0 when ConvoHub did not list the message).
	 */
	public function create_email_conversation( $inbox_id, array $contact, $subject, $text, $html, array $options = array() ) {
		$message = array_merge(
			array(
				'content'            => $text,
				'email_html_content' => $html,
				'message_type'       => 'outgoing',
				'private'            => false,
			),
			array_intersect_key( $options, array_flip( array( 'to_emails', 'cc_emails', 'bcc_emails' ) ) )
		);

		$data = $this->account_request(
			'POST',
			'/conversations',
			array(
				'inbox_id'              => (int) $inbox_id,
				'contact'               => $contact,
				'additional_attributes' => array( 'mail_subject' => $subject ),
				'message'               => $message,
			)
		);
		if ( is_wp_error( $data ) ) {
			return $data;
		}
		return array(
			'conversation_id' => (int) ( $data['id'] ?? 0 ),
			'message_id'      => (int) ( $data['messages'][0]['id'] ?? 0 ),
		);
	}

	/**
	 * Sends a WhatsApp template or an email to a contact through the Developer API.
	 *
	 * The payload is `{inbox_id, type: 'whatsapp_template' | 'text', contact: {...}, message: {...}}`. For an email use
	 * create_email_conversation(): this API cannot set a subject or HTML.
	 * Each call creates a conversation unless the inbox is locked to a single conversation per contact.
	 * ConvoHub answers a payload it cannot use with a generic 422.
	 *
	 * @param array $payload Message payload.
	 * @return array|WP_Error `message_id` and `conversation_id` of the created message.
	 */
	public function send_message( array $payload ) {
		if ( $this->account_id <= 0 ) {
			return new WP_Error( 'convohub_no_account', __( 'Choose a ConvoHub account first.', 'convohub' ) );
		}
		return $this->request( 'POST', '/convohub/developer/api/v1/messages', $payload, array( 'api_account_id' => (string) $this->account_id ) );
	}

	/**
	 * The most recent messages of a conversation, including each message's delivery `status`.
	 *
	 * @param int $conversation_id Conversation ID (the `conversation_id` returned when the message was sent).
	 * @return array|WP_Error List of messages.
	 */
	public function conversation_messages( $conversation_id ) {
		$data = $this->account_request( 'GET', '/conversations/' . absint( $conversation_id ) . '/messages' );
		return is_wp_error( $data ) ? $data : (array) ( $data['payload'] ?? array() );
	}

	/**
	 * Searches contacts. ConvoHub matches the text anywhere in the name, email, phone number or identifier, so the
	 * caller must pick the exact contact from the result.
	 *
	 * @param string $query Search text.
	 * @return array|WP_Error List of contacts (a first page only).
	 */
	public function search_contacts( $query ) {
		$data = $this->account_request( 'GET', '/contacts/search?q=' . rawurlencode( $query ) );
		return is_wp_error( $data ) ? $data : (array) ( $data['payload'] ?? array() );
	}

	/**
	 * Merges custom attributes into a contact. Attributes that are not sent are kept.
	 *
	 * @param int   $contact_id        Contact ID.
	 * @param array $custom_attributes Attribute name => value.
	 * @return array|WP_Error
	 */
	public function update_contact_attributes( $contact_id, array $custom_attributes ) {
		return $this->account_request( 'PATCH', '/contacts/' . absint( $contact_id ), array( 'custom_attributes' => $custom_attributes ) );
	}

	/**
	 * Connects an integration app to the account (for example `woocommerce`).
	 *
	 * @param string $app_id   App ID.
	 * @param array  $settings App settings.
	 * @return array|WP_Error The created hook.
	 */
	public function create_integration_hook( $app_id, array $settings ) {
		return $this->account_request(
			'POST',
			'/integrations/hooks',
			array(
				'hook' => array(
					'app_id'   => $app_id,
					'settings' => $settings,
				),
			)
		);
	}

	/**
	 * Disconnects an integration.
	 *
	 * @param int $hook_id Hook ID.
	 * @return array|WP_Error
	 */
	public function delete_integration_hook( $hook_id ) {
		return $this->account_request( 'DELETE', '/integrations/hooks/' . absint( $hook_id ) );
	}

	/**
	 * Webhooks registered on the account.
	 *
	 * @return array|WP_Error List of webhooks (id, url, subscriptions, secret).
	 */
	public function webhooks() {
		$data = $this->account_request( 'GET', '/webhooks' );
		return is_wp_error( $data ) ? $data : (array) ( $data['payload']['webhooks'] ?? array() );
	}

	/**
	 * Registers an account webhook.
	 *
	 * @param string   $url    Public URL ConvoHub posts events to.
	 * @param string   $name   Webhook name.
	 * @param string[] $events Event names to subscribe to.
	 * @return array|WP_Error The created webhook, including its signing secret.
	 */
	public function create_webhook( $url, $name, array $events ) {
		$data = $this->account_request(
			'POST',
			'/webhooks',
			array(
				'webhook' => array(
					'url'           => $url,
					'name'          => $name,
					'subscriptions' => $events,
				),
			)
		);
		return is_wp_error( $data ) ? $data : (array) ( $data['payload']['webhook'] ?? array() );
	}

	/**
	 * Changes the events a webhook is subscribed to. ConvoHub does not allow changing its URL.
	 *
	 * @param int      $webhook_id Webhook ID.
	 * @param string[] $events     Event names.
	 * @return array|WP_Error The updated webhook.
	 */
	public function update_webhook_events( $webhook_id, array $events ) {
		$data = $this->account_request( 'PATCH', '/webhooks/' . absint( $webhook_id ), array( 'webhook' => array( 'subscriptions' => $events ) ) );
		return is_wp_error( $data ) ? $data : (array) ( $data['payload']['webhook'] ?? array() );
	}

	/**
	 * Deletes a webhook.
	 *
	 * @param int $webhook_id Webhook ID.
	 * @return array|WP_Error
	 */
	public function delete_webhook( $webhook_id ) {
		return $this->account_request( 'DELETE', '/webhooks/' . absint( $webhook_id ) );
	}

	/**
	 * Synced message templates of an inbox.
	 *
	 * @param int $inbox_id Inbox ID.
	 * @return array|WP_Error List of templates.
	 */
	public function message_templates( $inbox_id ) {
		$data = $this->account_request( 'GET', '/inboxes/' . absint( $inbox_id ) . '/message_templates' );
		return is_wp_error( $data ) ? $data : (array) ( $data['payload'] ?? array() );
	}

	/**
	 * Performs an account-scoped request.
	 *
	 * @param string     $method HTTP method.
	 * @param string     $suffix Path after `/api/v1/accounts/:id`.
	 * @param array|null $body   JSON body.
	 * @return array|WP_Error
	 */
	private function account_request( $method, $suffix, $body = null ) {
		if ( $this->account_id <= 0 ) {
			return new WP_Error( 'convohub_no_account', __( 'Choose a ConvoHub account first.', 'convohub' ) );
		}
		return $this->request( $method, '/api/v1/accounts/' . $this->account_id . $suffix, $body );
	}

	/**
	 * Performs a request and normalizes failures into a WP_Error.
	 *
	 * @param string     $method HTTP method.
	 * @param string     $path   Path starting with a slash.
	 * @param array|null $body    JSON body.
	 * @param array      $headers Extra request headers.
	 * @return array|WP_Error Decoded JSON body (empty array for an empty body).
	 */
	public function request( $method, $path, $body = null, array $headers = array() ) {
		if ( '' === $this->token ) {
			return new WP_Error( 'convohub_not_connected', __( 'ConvoHub is not connected.', 'convohub' ) );
		}

		$args = array(
			'method'      => $method,
			'timeout'     => 15,
			'redirection' => 0,
			'headers'     => array_merge(
				array(
					'api_access_token' => $this->token,
					'Accept'           => 'application/json',
					'Content-Type'     => 'application/json',
				),
				$headers
			),
		);
		if ( null !== $body ) {
			$args['body'] = wp_json_encode( $body );
		}

		$response = wp_remote_request( ConvoHub_Settings::BASE_URL . $path, $args );
		if ( is_wp_error( $response ) ) {
			return new WP_Error(
				'convohub_unreachable',
				/* translators: %s: error message from the HTTP layer. */
				sprintf( __( 'Could not reach ConvoHub: %s', 'convohub' ), $response->get_error_message() )
			);
		}

		$status = (int) wp_remote_retrieve_response_code( $response );
		$data   = json_decode( wp_remote_retrieve_body( $response ), true );

		if ( $status < 200 || $status >= 300 ) {
			return self::error_from_response( $status, $data );
		}

		return is_array( $data ) ? $data : array();
	}

	/**
	 * Maps ConvoHub's error shapes (`{error}` or `{message, attributes}`) to one WP_Error.
	 *
	 * @param int   $status HTTP status.
	 * @param mixed $data   Decoded body.
	 * @return WP_Error
	 */
	public static function error_from_response( $status, $data ) {
		$detail = '';
		if ( is_array( $data ) ) {
			$detail = (string) ( $data['error'] ?? $data['message'] ?? '' );
		}

		switch ( $status ) {
			case 401:
				$code    = 'convohub_unauthorized';
				$message = __( 'ConvoHub no longer accepts this site\'s access. Disconnect, then connect again with a new key.', 'convohub' );
				break;
			case 402:
				$code    = 'convohub_billing';
				$message = __( 'The ConvoHub account is in read-only billing mode or has hit a plan limit.', 'convohub' );
				break;
			case 403:
				$code    = 'convohub_api_disabled';
				$message = __( 'API access is not enabled for this ConvoHub account.', 'convohub' );
				break;
			case 404:
				$code    = 'convohub_not_found';
				$message = __( 'ConvoHub could not find that resource.', 'convohub' );
				break;
			case 422:
				$code    = 'convohub_invalid';
				$message = '' !== $detail ? $detail : __( 'ConvoHub rejected the request.', 'convohub' );
				break;
			case 429:
				$code    = 'convohub_rate_limited';
				$message = __( 'ConvoHub is rate limiting requests. Try again shortly.', 'convohub' );
				break;
			default:
				$code = $status >= 500 ? 'convohub_server_error' : 'convohub_error';
				/* translators: %d: HTTP status code. */
				$message = sprintf( __( 'ConvoHub returned an unexpected response (HTTP %d).', 'convohub' ), $status );
		}//end switch

		return new WP_Error(
			$code,
			$message,
			array(
				'status' => $status,
				'detail' => $detail,
			)
		);
	}
}