<?php
/**
 * Theme Revisions API.
 *
 * @package Theme_Revisions
 * @todo Alot.
 */

// TODO: Functions for previewing, sandboxing, saving, moving, and deleting files.
//       Oh, and making these functions below actually perform tasks.

/**
 * Gets revised theme object.
 *
 * @param $theme
 * @return object Post object of the revised_theme post_type
 */
function get_revised_theme_object( $theme ) {
	if ( $post = get_page_by_title( $theme, OBJECT, 'revised_theme' ) )
		return $post;
	return false;
}

/**
 * Gets file data for a revised theme.
 *
 * @todo Also return revision data.
 *
 * @param string $theme
 * @param $file Not implemented.
 * @return array Revision data
 */
function get_theme_file_data( $theme, $file = null ) {
	if ( $theme_obj = get_revised_theme_object( $theme ) )
		return get_posts( array(
			'post_parent' => $theme_obj->ID,
			'post_status' => 'any',
			'post_type' => 'theme_file',
			) );
	return false;
}

/**
 * Gets revision data for a file.
 *
 * @param string $theme
 * @param string $file Not implemented.
 * @return array Revision data
 */
function get_theme_file_revision_data( $theme, $file = null ) {
	if ( ! $file_data = get_theme_file_data( $theme ) )
		return false;
	$ids = array();
	foreach ( $file_data as $file )
		$ids[] = $file->ID;
	$revisions = get_posts( array(
		'post_type' => 'theme_file_revision',
		'post_status' => 'any',
		'suppress_filters' => false,
		'post_parent__in' => array( $ids ),
	) );
	// @todo map this to each file.
	return $revisions;
}

//
// Revision setters.
//

/**
 * Creates a theme revision based on a file.
 *
 * @param string $theme Theme root
 * @param string $file File, relative to theme
 * @param string|null $new_content Optional. New content. Defaults to null, which then uses content on disk.
 * @param bool $check_changes Optional. Whether the file should be checked for changes before generating a revision.
 * @return int|WP_Error The value 0 or WP_Error on failure. The post ID on success.
 */
function create_theme_file_revision( $theme, $file, $new_content = null, $check_changes = true ) {
	if ( null === $new_content ) {
		$f = fopen( $file, 'r' );
		$new_content = fread( $f, filesize( $file ) );
	}

	$revised_theme = get_theme_revision_data( $theme );
	$revisions = get_theme_file_revision_data( $theme, $file );
	$last_revision = empty( $revisions ) ? 0 : end( $revisions );

	if ( $last_revision && $check_changes && $last_revision->post_name == md5( $new_content ) )
		return false;

	$args = array(
		'post_type' => 'theme_revision',
		'post_content' => $new_content,
		'post_name' => $last_revision ? md5( $new_content ) : $file,
		'post_parent' => $last_revision ? $last_revision->ID : $revised_theme->ID,
		'post_status' => 'draft',
		'post_author' => get_current_user_id(),
	);

	return wp_insert_post( $args );
}

/**
 * Generates initial revisions for a theme.
 *
 * Returns false if theme already has revisions.
 *
 * @param string $theme
 * @return bool True on success, false on failure.
 */
function start_theme_revisions( $theme ) {
	if ( get_revised_theme_object( $theme ) )
		return false;
	$theme_data = get_theme( $theme );
	$allowed_files = array_merge( $theme_data['Stylesheet Files'], $theme_data['Template Files'] );
	foreach ( $allowed_files as $file )
		create_theme_file_revision( $theme, $file );
	return true;
}

/**
 * Deletes a theme file revision.
 *
 * @param int $revision
 * @return bool|WP_Error True on success, WP_Error on failure.
 */
function delete_theme_file_revision( $revision ) {
	if ( ! $post = get_post( $revision ) )
		return false;
	if ( $post->post_type != 'theme_file_revision' )
		return false;
	return wp_delete_post( $revision, true );
}

//
// Snapshot functions
//

/**
 * Create a theme snapshot.
 *
 * @param string $theme
 * @return int|WP_Error ID of snapshot term on success, WP_Error on failure.
 */
function create_theme_snapshot( $theme ) {
	$revised_theme = get_theme_revision_data( $theme );
	$for_snapshot = array();
	$term_id = wp_insert_term( 'snapshot-' . current_time('timestamp'), 'snapshot' );
	if ( is_wp_error( $term_id ) )
		return $term_id;
	foreach ( $revised_theme as $revised_file ) {
		$file = end( $revised_file['revisions'] );
		wp_set_object_terms( $file->ID, array( $term_id ), 'snapshot', true );
	}
	return $term_id;
}

/**
 * Restores a theme snapshot.
 *
 * @param int $snapshot Snapshot's term ID
 * @return bool|WP_Error True on success, WP_Error on failure.
 */
function restore_theme_snapshot( $snapshot ) {
	$snapshot_term = get_objects_in_term( $snapshot, 'snapshot' );
	// fetch most recent theme file revision IDs
	// copy over the snapshot term
}

/**
 * Delete a theme snapshot.
 *
 * @param int $snapshot Snapshot's term ID
 * @return bool|WP_Error ID of snapshot term on success, WP_Error on failure.
 */
function delete_theme_snapshot( $snapshot ) {
	return wp_delete_term( $snapshot, 'snapshot' );
}

/**
 * Restores a file to a revision.
 *
 * @todo This code doesn't make much sense yet. Yeah.
 *
 * @param string $theme
 * @param string $file
 * @return bool|WP_Error True on success, WP_Error on failure.
 */
function restore_theme_file_revision( $theme, $file, $revision ) {
	$revised_theme = get_theme_revision_data( $theme );
	$revised_file  = get_theme_file_revision_data( $theme, $file );
	$restoring = get_post( $revised_file[0]->ID );
	$restoring['ID'] = $revision;
	return wp_insert_post( $restoring );
}

/**
 * Gets most recent revisions to a theme's files.
 *
 * @param string $theme
 * @param int $count Optional. Number of recent revisions. Default 20.
 * @param bool $duplicate Optional. Whether to return multiple revisions of the same file. Default true.
 * @return array Revision data, sorted by date descending.
 */
function get_recent_theme_revisions( $theme, $count = 20, $duplicate = true ) {}