import Routing
import Vapor
import SQLite

private let fm = FileManager.default

private let baseFolder = URL(fileURLWithPath: "/caps")

private let imageFolder = URL(fileURLWithPath: "/caps/public/images")

private let dbFile = "/caps/db.sqlite3"

private let tempImageFile = imageFolder.appendingPathComponent("temp.jpg")

private var db: Connection!

private let id = Expression<Int>("id")

private let name = Expression<String>("name")

private let table = Table("caps")

func loadDatabase() throws {
    db = try Connection(dbFile)
}

private func select(_ cap: Int) -> Table {
    table.filter(id == cap)
}

private func folder(of cap: Int) -> URL {
    imageFolder.appendingPathComponent(String(format: "%04d", cap))
}

private func file(of cap: Int, version: Int) -> URL {
    folder(of: cap).appendingPathComponent(String(format: "%04d-%02d.jpg", cap, version))
}

private func countImages(in folder: URL) throws -> Int {
    try fm.contentsOfDirectory(at: folder, includingPropertiesForKeys: nil).filter({ $0.pathExtension == "jpg" }).count
}

private func count(of cap: Int) throws -> Int {
    let f = folder(of: cap)
    guard fm.fileExists(atPath: f.path) else {
        throw CapError.unknownId
    }
    return try countImages(in: f)
}

/// Register your application's routes here.
///
/// [Learn More →](https://docs.vapor.codes/3.0/getting-started/structure/#routesswift)
public func routes(_ router: Router) throws {
    
    // Get the name of a cap
    router.getCatching("name", Int.parameter) { request -> Data in
        let cap = try request.parameters.next(Int.self)
        guard let row = try db.pluck(table.select(name).filter(id == cap)) else {
            throw CapError.unknownId
        }
        return row[name].data(using: .utf8)!
    }
    
    // Set the name of a cap
    router.postCatching("name", Int.parameter) { request in
        let cap = try request.parameters.next(Int.self)
        guard let data = request.http.body.data, let string = String(data: data, encoding: .utf8) else {
            throw CapError.invalidBody
        }
        guard let _ = try db.pluck(select(cap)) else {
            try db.run(select(cap).insert(id <- cap, name <- string))
            return
        }
        try db.run(select(cap).update(name <- string))
    }
    
    // Upload an image
    router.postCatching("images", Int.parameter) { request -> Data in
        let cap = try request.parameters.next(Int.self)
        guard let data = request.http.body.data else {
            throw CapError.invalidBody
        }
        let c = try count(of: cap)
        let f = file(of: cap, version: c)
        guard !fm.fileExists(atPath: f.path) else {
            throw CapError.dataInconsistency
        }
        try data.write(to: f)
        return "\(c)".data(using: .utf8)!
    }
    
    // Get count of a cap
    router.getCatching("count", Int.parameter) { request -> Data in
        let cap = try request.parameters.next(Int.self)
        let c = try count(of: cap)
        return "\(c)".data(using: .utf8)!
    }
    
    // Get the count of all caps
    router.getCatching("count", "all") { request -> Data in
        let counts: [(id: Int, count: Int)] = try fm.contentsOfDirectory(at: imageFolder, includingPropertiesForKeys: nil).compactMap { folder in
            guard let id = Int(folder.lastPathComponent) else {
                return nil
            }
            guard let count = try? countImages(in: folder) else {
                return nil
            }
            return (id, count)
        }
        return counts.map { "\($0.id)#\($0.count)"}.joined(separator: ";").data(using: .utf8)!
    }
    
    // Set a different version as the main image
    router.getCatching("switch", Int.parameter, Int.parameter) { request in
        let cap = try request.parameters.next(Int.self)
        let version = try request.parameters.next(Int.self)
        guard version > 0 else {
            return
        }
        let file1 = file(of: cap, version: 0)
        guard fm.fileExists(atPath: file1.path) else {
            throw CapError.invalidFile
        }
        let file2 = file(of: cap, version: version)
        guard fm.fileExists(atPath: file2.path) else {
            throw CapError.invalidFile
        }
        try fm.moveItem(at: file1, to: tempImageFile)
        try fm.moveItem(at: file2, to: file1)
        try fm.moveItem(at: tempImageFile, to: file2)
    }
}