import Vapor

// MARK: Paths

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

private let logFile = baseFolder.appendingPathComponent("logs/server.log").path

private let publicFolder = baseFolder.appendingPathComponent("Public")

private let imageFolder = publicFolder.appendingPathComponent("images")

private let nameFile = publicFolder.appendingPathComponent("names.txt")

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

// MARK: Variables

private let fm = FileManager.default

private var caps = [String]()

// MARK: SQLite

func loadCapNames() throws {
    let s = try String(contentsOf: nameFile)
    caps = s.trimmingCharacters(in: .whitespacesAndNewlines).components(separatedBy: "\n")
    log("\(caps.count) caps loaded")
}

// MARK: Helper

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 {
        return 0
    }
    return try countImages(in: f)
}

// MARK: Routes

/// Register your application's routes here.
///
/// [Learn More →](https://docs.vapor.codes/3.0/getting-started/structure/#routesswift)
func routes(_ app: Application) throws {
    
    try Log.set(logFile: logFile)
    try loadCapNames()
    
    // Get the name of a cap
    app.getCatching("name", ":n") { request -> Data in
        guard let cap = request.parameters.get("n", as: Int.self) else {
            log("Invalid body data")
            throw Abort(.badRequest)
        }
        let index = cap - 1
        guard index >= 0, index < caps.count else {
            log("Trying to get name for invalid cap \(cap) (\(caps.count) caps loaded)")
            throw CapError.unknownId
        }
        return caps[index].data(using: .utf8)!
    }
    
    // Set the name of a cap
    app.postCatching("name", ":n") { request in
        guard let cap = request.parameters.get("n", as: Int.self) else {
            log("Invalid parameter for cap")
            throw Abort(.badRequest)
        }
        let index = cap - 1
        guard let buffer = request.body.data, let name = String(data: Data(buffer: buffer), encoding: .utf8) else {
            log("Invalid body data")
            throw CapError.invalidBody
        }
        guard index <= caps.count else {
            log("Trying to set name for cap \(cap), but only \(caps.count) caps exist")
            throw CapError.unknownId
        }
        
        if index == caps.count {
            caps.append(name)
            // Create image folder
            let url = folder(of: cap)
            if !fm.fileExists(atPath: url.path) {
                try fm.createDirectory(at: url, withIntermediateDirectories: false)
            }
            log("Added cap \(cap)")
        } else {
            caps[index] = name
            log("Set name for cap \(cap)")
        }
        try caps.joined(separator: "\n").data(using: .utf8)!.write(to: nameFile)
        
    }
    
    // Upload an image
    app.postCatching("images", ":n") { request -> Data in
        guard let cap = request.parameters.get("n", as: Int.self) else {
            log("Invalid parameter for cap")
            throw Abort(.badRequest)
        }
        guard let buffer = request.body.data else {
            log("Invalid body data")
            throw CapError.invalidBody
        }
        let data = Data(buffer: buffer)
        let c = try count(of: cap)
        let f = file(of: cap, version: c)
        guard !fm.fileExists(atPath: f.path) else {
            log("Image \(c) for cap \(cap) already exists on disk")
            throw CapError.dataInconsistency
        }
        try data.write(to: f)
        return "\(c)".data(using: .utf8)!
    }
    
    // Get count of a cap
    app.getCatching("count", ":c") { request -> Data in
        guard let cap = request.parameters.get("c", as: Int.self) else {
            log("Invalid parameter for cap")
            throw Abort(.badRequest)
        }
        let c = try count(of: cap)
        return "\(c)".data(using: .utf8)!
    }
    
    // Get the count of all caps
    app.getCatching("counts") { request -> Data in
        Data(try (1...caps.count).map({ UInt8(try count(of: $0)) }))
    }
    
    // Set a different version as the main image
    app.getCatching("switch", ":n", ":v") { request in
        guard let cap = request.parameters.get("n", as: Int.self) else {
            log("Invalid parameter for cap")
            throw Abort(.badRequest)
        }
        guard let version = request.parameters.get("v", as: Int.self) else {
            log("Invalid parameter for cap version")
            throw Abort(.badRequest)
        }
        guard version > 0 else {
            log("Not switching cap \(cap) to image \(version)")
            return
        }
        let file1 = file(of: cap, version: 0)
        guard fm.fileExists(atPath: file1.path) else {
            log("No image 0 for cap \(cap)")
            throw CapError.invalidFile
        }
        let file2 = file(of: cap, version: version)
        guard fm.fileExists(atPath: file2.path) else {
            log("No image \(version) for cap \(cap)")
            throw CapError.invalidFile
        }
        try fm.moveItem(at: file1, to: tempImageFile)
        try fm.moveItem(at: file2, to: file1)
        try fm.moveItem(at: tempImageFile, to: file2)
        log("Switched cap \(cap) to version \(version)")
    }
}