Re-structured the app code to be feature based rather than code type based

app/Entities/Book.php

@@ -0,0 +1,110 @@
+<?php namespace BookStack\Entities;
+
+use BookStack\Uploads\Image;
+use BookStack\Entities\Page;
+
+class Book extends Entity
+{
+    public $searchFactor = 2;
+
+    protected $fillable = ['name', 'description', 'image_id'];
+
+    /**
+     * Get the morph class for this model.
+     * @return string
+     */
+    public function getMorphClass()
+    {
+        return 'BookStack\\Book';
+    }
+
+    /**
+     * Get the url for this book.
+     * @param string|bool $path
+     * @return string
+     */
+    public function getUrl($path = false)
+    {
+        if ($path !== false) {
+            return baseUrl('/books/' . urlencode($this->slug) . '/' . trim($path, '/'));
+        }
+        return baseUrl('/books/' . urlencode($this->slug));
+    }
+
+    /**
+     * Returns book cover image, if book cover not exists return default cover image.
+     * @param int $width - Width of the image
+     * @param int $height - Height of the image
+     * @return string
+     */
+    public function getBookCover($width = 440, $height = 250)
+    {
+        $default = baseUrl('/book_default_cover.png');
+        if (!$this->image_id) {
+            return $default;
+        }
+
+        try {
+            $cover = $this->cover ? baseUrl($this->cover->getThumb($width, $height, false)) : $default;
+        } catch (\Exception $err) {
+            $cover = $default;
+        }
+        return $cover;
+    }
+
+    /**
+     * Get the cover image of the book
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function cover()
+    {
+        return $this->belongsTo(Image::class, 'image_id');
+    }
+
+    /**
+     * Get all pages within this book.
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function pages()
+    {
+        return $this->hasMany(Page::class);
+    }
+
+    /**
+     * Get all chapters within this book.
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function chapters()
+    {
+        return $this->hasMany(Chapter::class);
+    }
+
+    /**
+     * Get the shelves this book is contained within.
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
+     */
+    public function shelves()
+    {
+        return $this->belongsToMany(Bookshelf::class, 'bookshelves_books', 'book_id', 'bookshelf_id');
+    }
+
+    /**
+     * Get an excerpt of this book's description to the specified length or less.
+     * @param int $length
+     * @return string
+     */
+    public function getExcerpt($length = 100)
+    {
+        $description = $this->description;
+        return strlen($description) > $length ? substr($description, 0, $length-3) . '...' : $description;
+    }
+
+    /**
+     * Return a generalised, common raw query that can be 'unioned' across entities.
+     * @return string
+     */
+    public function entityRawQuery()
+    {
+        return "'BookStack\\\\Book' as entity_type, id, id as entity_id, slug, name, {$this->textField} as text,'' as html, '0' as book_id, '0' as priority, '0' as chapter_id, '0' as draft, created_by, updated_by, updated_at, created_at";
+    }
+}