//
//  Handlers.swift
//  Swifter
//  Copyright (c) 2014 Damian Kołakowski. All rights reserved.
//

import Foundation

public class HttpHandlers {
    
    private static let rangePrefix = "bytes="
    
    public class func directory(dir: String) -> (HttpRequest -> HttpResponse) {
        return { request in
            
            guard let localPath = request.params.first else {
                return HttpResponse.NotFound
            }
            
            let filesPath = dir + "/" + localPath.1
            
            guard let fileBody = NSData(contentsOfFile: filesPath) else {
                return HttpResponse.NotFound
            }
            
            if let rangeHeader = request.headers["range"] {
                
                guard rangeHeader.hasPrefix(HttpHandlers.rangePrefix) else {
                    return HttpResponse.BadRequest
                }
                
#if os(Linux)
                let rangeString = rangeHeader.substringFromIndex(HttpHandlers.rangePrefix.characters.count)
#else
                let rangeString = rangeHeader.substringFromIndex(rangeHeader.startIndex.advancedBy(HttpHandlers.rangePrefix.characters.count))
#endif
                let rangeStringExploded = rangeString.split("-")
                guard rangeStringExploded.count == 2 else {
                    return HttpResponse.BadRequest
                }
                
                let startStr = rangeStringExploded[0]
                let endStr   = rangeStringExploded[1]
                
                guard let start = Int(startStr), end = Int(endStr) else {
                    var array = [UInt8](count: fileBody.length, repeatedValue: 0)
                    fileBody.getBytes(&array, length: fileBody.length)
                    return HttpResponse.RAW(200, "OK", nil, array)
                }
                
                let length = end - start
                let range = NSRange(location: start, length: length + 1)
                
                guard range.location + range.length <= fileBody.length else {
                    return HttpResponse.RAW(416, "Requested range not satisfiable", nil, nil)
                }
                
                let subData = fileBody.subdataWithRange(range)
                
                let headers = [
                    "Content-Range" : "bytes \(startStr)-\(endStr)/\(fileBody.length)"
                ]
                
                var array = [UInt8](count: subData.length, repeatedValue: 0)
                subData.getBytes(&array, length: subData.length)
                return HttpResponse.RAW(206, "Partial Content", headers, array)
                
            }
            else {
                var array = [UInt8](count: fileBody.length, repeatedValue: 0)
                fileBody.getBytes(&array, length: fileBody.length)
                return HttpResponse.RAW(200, "OK", nil, array)
            }
            
        }
    }
    
    public class func directoryBrowser(dir: String) -> ( HttpRequest -> HttpResponse ) {
        return { r in
            if let (_, value) = r.params.first {
                let filePath = dir + "/" + value
                let fileManager = NSFileManager.defaultManager()
                var isDir: ObjCBool = false
                if fileManager.fileExistsAtPath(filePath, isDirectory: &isDir) {
                    if isDir {
                        do {
                            let files = try fileManager.contentsOfDirectoryAtPath(filePath)
                            var response = "<h3>\(filePath)</h3></br><table>"
                            response += files.map({ "<tr><td><a href=\"\(r.url)/\($0)\">\($0)</a></td></tr>"}).joinWithSeparator("")
                            response += "</table>"
                            return HttpResponse.OK(.Html(response))
                        } catch {
                            return HttpResponse.NotFound
                        }
                    } else {
                        if let fileBody = NSData(contentsOfFile: filePath) {
                            var array = [UInt8](count: fileBody.length, repeatedValue: 0)
                            fileBody.getBytes(&array, length: fileBody.length)
                            return HttpResponse.RAW(200, "OK", nil, array)
                        }
                    }
                }
            }
            return HttpResponse.NotFound
        }
    }
}