package middleware

import (
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"path/filepath"
	"strings"

	"bitbucket.org/PinIdea/fcgi_client" // TODO: Inline this dependency. It'll need some work.
)

// FastCGI is middleware that acts as a FastCGI client. Requests
// that get forwarded to FastCGI stop the middleware execution
// chain. The most common use for this layer is to serve PHP
// websites with php-fpm.
func FastCGI(p parser) Middleware {
	root := p.Root()

	var rules []fastCgi
	for p.Next() {
		rule := fastCgi{}
		if !p.Args(&rule.path, &rule.address) {
			return p.ArgErr()
		}
		rules = append(rules, rule)
	}

	return func(next http.HandlerFunc) http.HandlerFunc {
		return func(w http.ResponseWriter, r *http.Request) {

			servedFcgi := false
			for _, rule := range rules {
				if Path(r.URL.Path).Matches(rule.path) {
					servedFcgi = true

					// Get absolute file paths
					absPath, err := filepath.Abs(root + r.URL.Path)
					if err != nil {
						// TODO!
						log.Fatal(err)
					}

					// Get absolute file paths
					absRootPath, err := filepath.Abs(root)
					if err != nil {
						// TODO!
						log.Fatal(err)
					}

					// Separate remote IP and port
					var ip, port string
					if idx := strings.Index(r.RemoteAddr, ":"); idx > -1 {
						ip = r.RemoteAddr[idx:]
						port = r.RemoteAddr[:idx]
					} else {
						ip = r.RemoteAddr
					}

					// TODO: Do we really have to make this map from scratch for each request?
					env := make(map[string]string)
					env["SERVER_SOFTWARE"] = "caddy" // TODO: Obtain version info...
					env["SERVER_PROTOCOL"] = r.Proto
					env["SCRIPT_FILENAME"] = absPath
					env["REMOTE_ADDR"] = ip
					env["REMOTE_PORT"] = port
					env["REQUEST_METHOD"] = r.Method
					env["QUERY_STRING"] = r.URL.RawQuery
					env["DOCUMENT_URI"] = r.URL.Path
					env["DOCUMENT_ROOT"] = absRootPath

					fcgi, err := fcgiclient.Dial("tcp", rule.address)
					if err != nil {
						// TODO!
					}

					resp, err := fcgi.Get(env)
					if err != nil && err != io.EOF {
						// TODO!
					}

					body, err := ioutil.ReadAll(resp.Body)
					if err != nil {
						// TODO!
					}

					for key, vals := range resp.Header {
						for _, val := range vals {
							w.Header().Add(key, val)
						}
					}

					w.WriteHeader(resp.StatusCode)
					w.Write(body)

					break
				}
			}

			if !servedFcgi {
				next(w, r)
			}
		}
	}
}

type fastCgi struct {
	path    string
	address string
}