Back-end functionality for a comparison site

Welcome, We are currently developing a website for simultaneous comparison of books on a variety of online book shops. The successful freelancer will be building a set of PHP based functions to search, extract, return and sort books into the cheapest books from a range of online book shops. (note: The successful developer DOES NOT have to build/implement the UI, just the functionality listed above) Essentially, a user is initially confronted with a "search" page, where the user can enter the title or isbn of a given book into a search bar. The user can also add extra search bars in order to search for additional products with the aid of a simple addition button. Once the user has completed their input, they press a "Search" button. When the user submits the search bar(s) form, the following should happen. 1. The system iterates over a list of book e-commerce providers 2. For each site, for each title/isbn is queried and the results stored in a multi-dimensional array or similar data structure 3. Each search should return the top 5 results for each book with the most relevant appearing first 4. For each book, attributes that need to be captured include Title, Author, Edition (number and/or physical versus e-book) and price 5. Once all books have been searched and results have been compiled, results are to be returned in a tabular format as demonstrated in the attachment, with the cheapest listed first. 6. In each result, there should also appear an option to discard the current result and replace it with the next closest match Notes: - A list of the chosen book e-commerce sites (approximately 10) will be provided to the winning freelancer - Some of the sites have a direct API that can be utilised to return results, others will need to be manually scraped and indexed - The functional implementation should be in PHP - The developer DOES NOT need to complete the UI design or implementation, just purely the functionality that Should you have any clarifications/extra questions about the project, please message me Looking forward to your bids, TM