<?php
/**
 * AJAX endpoints for managing links from wp-admin — create / update / delete, proxied to the
 * panel's /api/v1. Every handler checks the nonce and requires `manage_options`, because a write
 * here changes the connected account, not just this WordPress site.
 *
 * @package AffKeeper
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

// phpcs:disable WordPress.Security.NonceVerification.Missing -- every handler calls $this->guard() first: check_ajax_referer() + current_user_can('manage_options') before any request data is read.
// phpcs:disable WordPress.Security.ValidatedSanitizedInput -- the flagged reads are boolean-ish flags strict-compared against literal strings ('1'/'true'/'on'), never stored or output raw; everything that is persisted goes through sanitize_text_field()/esc_url_raw() with wp_unslash().

class AffKeeper_Ajax {

	const NONCE = 'affkeeper_manage';

	private static $instance = null;

	public static function instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	public function hooks() {
		add_action( 'wp_ajax_affkeeper_create_link', array( $this, 'create' ) );
		add_action( 'wp_ajax_affkeeper_update_link', array( $this, 'update' ) );
		add_action( 'wp_ajax_affkeeper_delete_link', array( $this, 'delete' ) );
	}

	/**
	 * Shared guard: valid nonce + capability, or a JSON error and stop.
	 */
	private function guard() {
		if ( ! check_ajax_referer( self::NONCE, 'nonce', false ) ) {
			wp_send_json_error( array( 'message' => __( 'Security check failed — reload the page.', 'affkeeper' ) ), 403 );
		}
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( array( 'message' => __( 'You are not allowed to manage links.', 'affkeeper' ) ), 403 );
		}
	}

	/**
	 * Turn a WP_Error into a JSON error using its own HTTP status where present.
	 *
	 * @param WP_Error $err Error.
	 */
	private function fail( $err ) {
		$data   = $err->get_error_data();
		$status = is_array( $data ) && isset( $data['status'] ) ? (int) $data['status'] : 400;
		wp_send_json_error( array( 'message' => $err->get_error_message() ), $status );
	}

	public function create() {
		$this->guard();
		$dest = isset( $_POST['destination_url'] ) ? esc_url_raw( wp_unslash( $_POST['destination_url'] ) ) : '';
		if ( '' === $dest ) {
			wp_send_json_error( array( 'message' => __( 'A destination URL is required.', 'affkeeper' ) ), 400 );
		}

		// "This site" picked in the connected create form: the link lives HERE (local redirect,
		// local clicks) and is pushed up right away so the account monitors it from minute one.
		if ( AffKeeper_API::is_configured() && ! empty( $_POST['local'] ) ) {
			$create_data = array(
				'destination'  => $dest,
				'slug'         => isset( $_POST['slug'] ) ? sanitize_text_field( wp_unslash( $_POST['slug'] ) ) : '',
				'title'        => isset( $_POST['title'] ) ? sanitize_text_field( wp_unslash( $_POST['title'] ) ) : '',
				'is_affiliate' => ! empty( $_POST['is_affiliate'] ),
				'source_url'   => isset( $_POST['source_url'] ) ? esc_url_raw( wp_unslash( $_POST['source_url'] ) ) : '',
			);
			if ( isset( $_POST['monitored'] ) ) {
				$create_data['monitored'] = ( '1' === (string) $_POST['monitored'] );
			}
			$dupe = empty( $_POST['slug'] ) ? AffKeeper_Local::recent_duplicate( $dest ) : null;
			if ( $dupe ) {
				wp_send_json_success( array( 'id' => (int) $dupe->id ) ); // double-submit: reuse, don't twin
			}
			$id = AffKeeper_Local::create( $create_data );
			if ( is_wp_error( $id ) ) {
				$this->fail( $id );
			}
			$row = AffKeeper_Local::get( (int) $id );
			if ( $row && ! empty( $row->monitored ) ) {
				$pushed = AffKeeper_Sync::push_one( $row ); // best-effort; the hourly sync re-pushes if it failed
				if ( 'quota' === $pushed ) {
					// The redirect works — but the account can't monitor it. Surface that on the
					// next page load instead of silently pretending it's covered.
					set_transient( 'affkeeper_create_warning', __( 'Link created — it redirects from this site, but it is NOT monitored: your plan\'s monitored-link limit is reached.', 'affkeeper' ), 120 );
				}
			}
			wp_send_json_success( array( 'id' => $id ) );
		}

		// No account connected → save to the local store (free tier). The link redirects from this
		// site's own domain and counts clicks locally; nothing leaves the server.
		if ( ! AffKeeper_API::is_configured() ) {
			$dupe = empty( $_POST['slug'] ) ? AffKeeper_Local::recent_duplicate( $dest ) : null;
			if ( $dupe ) {
				wp_send_json_success( array( 'id' => (int) $dupe->id ) ); // double-submit: reuse, don't twin
			}
			$id = AffKeeper_Local::create(
				array(
					'destination'  => $dest,
					'slug'         => isset( $_POST['slug'] ) ? sanitize_text_field( wp_unslash( $_POST['slug'] ) ) : '',
					'title'        => isset( $_POST['title'] ) ? sanitize_text_field( wp_unslash( $_POST['title'] ) ) : '',
					'is_affiliate' => ! empty( $_POST['is_affiliate'] ),
					'source_url'   => isset( $_POST['source_url'] ) ? esc_url_raw( wp_unslash( $_POST['source_url'] ) ) : '',
				)
			);
			if ( is_wp_error( $id ) ) {
				$this->fail( $id );
			}
			wp_send_json_success( array( 'id' => $id ) );
		}

		$payload = array(
			'destination_url' => $dest,
			'is_affiliate'    => ! empty( $_POST['is_affiliate'] ),
		);
		$slug = isset( $_POST['slug'] ) ? sanitize_text_field( wp_unslash( $_POST['slug'] ) ) : '';
		if ( '' !== $slug ) {
			$payload['slug'] = $slug;
		}
		$source = isset( $_POST['source_url'] ) ? esc_url_raw( wp_unslash( $_POST['source_url'] ) ) : '';
		if ( '' !== $source ) {
			$payload['source_url'] = $source;
		}
		$domain = isset( $_POST['domain_id'] ) ? sanitize_text_field( wp_unslash( $_POST['domain_id'] ) ) : '';
		if ( '' !== $domain ) {
			$payload['domain_id'] = $domain;
		}

		$result = AffKeeper_API::create_link( $payload );
		if ( is_wp_error( $result ) ) {
			$this->fail( $result );
		}
		wp_send_json_success( $result );
	}

	public function update() {
		$this->guard();
		$id       = isset( $_POST['id'] ) ? sanitize_text_field( wp_unslash( $_POST['id'] ) ) : '';
		$local_id = isset( $_POST['local_id'] ) ? absint( $_POST['local_id'] ) : 0;
		// An unsynced local link (plan limit) has no remote id — local_id alone is enough.
		if ( '' === $id && $local_id <= 0 ) {
			wp_send_json_error( array( 'message' => __( 'Missing link id.', 'affkeeper' ) ), 400 );
		}

		// Local (free) tier: the id IS the local row id.
		if ( ! AffKeeper_API::is_configured() ) {
			$this->apply_local_update( (int) $id );
			wp_send_json_success();
		}

		// Connected + a synced link (source='wordpress'): it lives here, so edit the local row (the
		// redirect) and mirror the monitoring-relevant fields up to the account's record ($id = remote
		// id). Editing it in the panel instead would leave the real redirect stale.
		if ( $local_id > 0 ) {
			// A stale tab can carry ids of rows that were re-created since (rename/delete cycles) —
			// without this check the slug validation excludes the wrong row and 409s confusingly.
			if ( ! AffKeeper_Local::get( $local_id ) ) {
				wp_send_json_error( array( 'message' => __( 'This link changed in the meantime — reload the page and try again.', 'affkeeper' ) ), 409 );
			}
			$this->apply_local_update( $local_id );
			// Monitor toggle transitions: off → free the plan slot (drop the account record);
			// on → claim one (push). The redirect itself is untouched either way.
			if ( isset( $_POST['monitored'] ) ) {
				$fresh_l = AffKeeper_Local::get( $local_id );
				$mon_on  = ( '1' === (string) $_POST['monitored'] );
				if ( $fresh_l && ! $mon_on && ! empty( $fresh_l->remote_id ) ) {
					AffKeeper_API::delete_link( $fresh_l->remote_id ); // best-effort
					AffKeeper_Local::update( $local_id, array( 'remote_id' => '' ) );
					wp_send_json_success();
				}
				if ( $fresh_l && $mon_on && empty( $fresh_l->remote_id ) ) {
					$pushed = AffKeeper_Sync::push_one( $fresh_l );
					if ( 'quota' === $pushed ) {
						set_transient( 'affkeeper_create_warning', __( 'Monitoring could not be enabled: your plan\'s monitored-link limit is reached.', 'affkeeper' ), 120 );
					}
					wp_send_json_success();
				}
			}
			$pdata = array();
			if ( isset( $_POST['destination_url'] ) ) {
				$pdata['destination_url'] = esc_url_raw( wp_unslash( $_POST['destination_url'] ) );
			}
			if ( isset( $_POST['is_affiliate'] ) ) {
				$pdata['is_affiliate'] = ( '1' === (string) $_POST['is_affiliate'] || 'true' === (string) $_POST['is_affiliate'] );
			}
			if ( '' !== $id ) {
				// This site is authoritative for the short URL: always report it (covers slug
				// renames) and confirm — a WP-side edit overrides any pending panel request.
				$fresh = AffKeeper_Local::get( $local_id );
				if ( $fresh ) {
					$pdata['external_url'] = AffKeeper_Local::short_url( $fresh );
				}
				$pdata['wp_synced'] = true;
				AffKeeper_API::update_link( $id, $pdata ); // best-effort; the local row is the source of truth
			}
			wp_send_json_success();
		}

		$payload = array();
		if ( isset( $_POST['destination_url'] ) ) {
			$payload['destination_url'] = esc_url_raw( wp_unslash( $_POST['destination_url'] ) );
		}
		if ( isset( $_POST['source_url'] ) ) {
			$payload['source_url'] = esc_url_raw( wp_unslash( $_POST['source_url'] ) );
		}
		// Sent as a string (empty = clear the alias); only forwarded when present so an edit that
		// doesn't touch the slug leaves it alone.
		if ( isset( $_POST['custom_slug'] ) ) {
			$payload['custom_slug'] = sanitize_text_field( wp_unslash( $_POST['custom_slug'] ) );
		}
		// Booleans only when explicitly sent, so an edit form can PATCH a subset.
		if ( isset( $_POST['is_affiliate'] ) ) {
			$payload['is_affiliate'] = ( '1' === (string) $_POST['is_affiliate'] || 'true' === (string) $_POST['is_affiliate'] );
		}
		if ( isset( $_POST['is_active'] ) ) {
			$payload['is_active'] = ( '1' === (string) $_POST['is_active'] || 'true' === (string) $_POST['is_active'] );
		}

		$result = AffKeeper_API::update_link( $id, $payload );
		if ( is_wp_error( $result ) ) {
			$this->fail( $result );
		}
		wp_send_json_success( $result );
	}

	public function delete() {
		$this->guard();
		$id       = isset( $_POST['id'] ) ? sanitize_text_field( wp_unslash( $_POST['id'] ) ) : '';
		$local_id = isset( $_POST['local_id'] ) ? absint( $_POST['local_id'] ) : 0;
		// An unsynced local link (plan limit) has no remote id — local_id alone is enough.
		if ( '' === $id && $local_id <= 0 ) {
			wp_send_json_error( array( 'message' => __( 'Missing link id.', 'affkeeper' ) ), 400 );
		}

		// Local (free) tier: the id IS the local row id.
		if ( ! AffKeeper_API::is_configured() ) {
			if ( ! AffKeeper_Local::delete( (int) $id ) ) {
				wp_send_json_error( array( 'message' => __( 'Could not delete the link.', 'affkeeper' ) ), 400 );
			}
			wp_send_json_success();
		}

		// Connected + a synced link: remove BOTH the local redirect and the account's monitoring
		// record, so nothing is left half-deleted (a dead redirect or an orphaned monitor).
		if ( $local_id > 0 ) {
			AffKeeper_Local::delete( $local_id );
			if ( '' !== $id ) {
				AffKeeper_API::delete_link( $id ); // best-effort
			}
			wp_send_json_success();
		}

		$result = AffKeeper_API::delete_link( $id );
		if ( is_wp_error( $result ) ) {
			$this->fail( $result );
		}
		wp_send_json_success();
	}

	/**
	 * Apply the edit form's fields to a local link row. Sends a JSON error (and stops) on a slug
	 * clash or DB failure; returns on success. Shared by the free-tier edit and the synced-link edit.
	 *
	 * @param int $local_id Local row id.
	 */
	private function apply_local_update( $local_id ) {
		$data = array();
		if ( isset( $_POST['destination_url'] ) ) {
			$data['destination'] = esc_url_raw( wp_unslash( $_POST['destination_url'] ) );
		}
		if ( isset( $_POST['title'] ) ) {
			$data['title'] = sanitize_text_field( wp_unslash( $_POST['title'] ) );
		}
		if ( isset( $_POST['source_url'] ) ) {
			$data['source_url'] = esc_url_raw( wp_unslash( $_POST['source_url'] ) );
		}
		if ( isset( $_POST['is_affiliate'] ) ) {
			$data['is_affiliate'] = ( '1' === (string) $_POST['is_affiliate'] || 'true' === (string) $_POST['is_affiliate'] );
		}
		if ( isset( $_POST['monitored'] ) ) {
			$data['monitored'] = ( '1' === (string) $_POST['monitored'] );
		}
		// The edit form sends the alias as custom_slug; the local store calls it slug.
		$slug = null;
		if ( isset( $_POST['custom_slug'] ) ) {
			$slug = sanitize_title( wp_unslash( $_POST['custom_slug'] ) );
		} elseif ( isset( $_POST['slug'] ) ) {
			$slug = sanitize_title( wp_unslash( $_POST['slug'] ) );
		}
		if ( null !== $slug && '' !== $slug ) {
			if ( AffKeeper_Local::slug_exists( $slug, (int) $local_id ) ) {
				$holder = AffKeeper_Local::get_by_slug( $slug );
				wp_send_json_error( array( 'message' => sprintf(
					/* translators: 1: the slug, 2: id of the row using it, 3: id the form edited. */
					__( 'Slug "%1$s" is already used by another link (#%2$s; you were editing #%3$s). Reload the page and try again.', 'affkeeper' ),
					$slug,
					$holder ? (int) $holder->id : 0,
					(int) $local_id
				) ), 409 );
			}
			$data['slug'] = $slug;
		}
		if ( ! AffKeeper_Local::update( (int) $local_id, $data ) ) {
			wp_send_json_error( array( 'message' => __( 'Could not update the link.', 'affkeeper' ) ), 400 );
		}
	}
}