package main

import (
	"crypto/tls"
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"strings"

	"code.rocketnine.space/tslocum/gmitohtml/pkg/gmitohtml"
)

var cssBytes = []byte(gmitohtml.StyleCSS)

func serveHTTPS(w http.ResponseWriter, r *http.Request) (int, int64, string) {
	if r.URL.Path == "" {
		// Redirect to /
		u, err := url.Parse(r.URL.String())
		if err != nil {
			status := http.StatusInternalServerError
			http.Error(w, "Failed to parse URL", status)
			return status, -1, ""
		}
		u.Path += "/"

		status := http.StatusTemporaryRedirect
		http.Redirect(w, r, u.String(), status)
		return status, -1, ""
	}

	pathBytes := []byte(r.URL.Path)
	strippedPath := r.URL.Path
	if strippedPath[0] == '/' {
		strippedPath = strippedPath[1:]
	}

	if host, ok := config.Hosts[r.URL.Hostname()]; ok {
		if strings.HasSuffix(r.URL.Path, "/assets/style.css") {
			status := http.StatusOK
			w.Header().Set("Content-Type", cssType)
			w.WriteHeader(status)

			if r.Method == "HEAD" {
				return status, 0, ""
			}

			if host.css != nil {
				w.Write(host.css)
			} else {
				w.Write(cssBytes)
			}
			return status, int64(len(cssBytes)), ""
		}

		for _, serve := range host.Paths {
			matchedRegexp := serve.r != nil && serve.r.Match(pathBytes)
			matchedPrefix := serve.r == nil && strings.HasPrefix(r.URL.Path, serve.Path)
			if !matchedRegexp && !matchedPrefix {
				continue
			}

			requireInput := serve.Input != "" || serve.SensitiveInput != ""
			if r.URL.RawQuery == "" && requireInput {
				if serve.SensitiveInput != "" {
					// TODO
				}
				status := http.StatusInternalServerError
				http.Error(w, "Gemini to HTML conversion is not supported for this page", status)
				return status, -1, serve.Log
			}

			if matchedRegexp || matchedPrefix {
				if serve.Root == "" || serve.FastCGI != "" {
					status := http.StatusInternalServerError
					http.Error(w, "Gemini to HTML conversion is not supported for this page", status)
					return status, -1, serve.Log
				}

				var filePath string
				if serve.Root != "" {
					root := serve.Root
					if root[len(root)-1] != '/' {
						root += "/"
					}

					requestSplit := strings.Split(r.URL.Path, "/")

					if !serve.SymLinks {
						for i := 1; i < len(requestSplit); i++ {
							info, err := os.Lstat(path.Join(root, strings.Join(requestSplit[1:i+1], "/")))
							if err != nil || info.Mode()&os.ModeSymlink == os.ModeSymlink {
								http.NotFound(w, r)
								return http.StatusNotFound, -1, serve.Log
							}
						}
					}

					filePath = path.Join(root, strings.Join(requestSplit[1:], "/"))
				}

				fi, err := os.Stat(filePath)
				if err != nil {
					http.NotFound(w, r)
					return http.StatusNotFound, -1, serve.Log
				}

				mode := fi.Mode()
				hasTrailingSlash := len(r.URL.Path) > 0 && r.URL.Path[len(r.URL.Path)-1] == '/'
				if mode.IsDir() {
					if !hasTrailingSlash {
						u, err := url.Parse(r.URL.String())
						if err != nil {
							status := http.StatusInternalServerError
							http.Error(w, "Failed to parse URL", status)
							return status, -1, serve.Log
						}
						u.Path += "/"

						status := http.StatusTemporaryRedirect
						http.Redirect(w, r, u.String(), status)
						return status, -1, serve.Log
					}

					var found bool
					for _, indexFile := range indexFiles {
						_, err := os.Stat(path.Join(filePath, indexFile))
						if err == nil || os.IsExist(err) {
							filePath = path.Join(filePath, indexFile)
							found = true
							break
						}
					}
					if !found {
						if serve.List {
							dirList, err := buildDirList(r.URL, filePath)
							if err != nil {
								status := http.StatusInternalServerError
								http.Error(w, "Failed to build directory listing", status)
								return status, -1, serve.Log
							}
							result := gmitohtml.Convert([]byte(dirList), r.URL.String())

							status := http.StatusOK
							w.Header().Set("Content-Type", htmlType)
							w.WriteHeader(status)

							if r.Method == "HEAD" {
								return status, 0, serve.Log
							}
							w.Write(result)
							return status, int64(len(result)), serve.Log
						}
						http.NotFound(w, r)
						return http.StatusNotFound, -1, serve.Log
					}
				} else if hasTrailingSlash && len(r.URL.Path) > 1 {
					u, err := url.Parse(r.URL.String())
					if err != nil {
						status := http.StatusInternalServerError
						http.Error(w, "Failed to parse URL", status)
						return status, -1, serve.Log
					}
					u.Path = u.Path[:len(u.Path)-1]

					status := http.StatusTemporaryRedirect
					http.Redirect(w, r, u.String(), status)
					return status, -1, serve.Log
				}

				data, err := ioutil.ReadFile(filePath)
				if err != nil {
					status := http.StatusInternalServerError
					http.Error(w, err.Error(), status)
					return status, -1, serve.Log
				}

				var result []byte
				contentType := htmlType
				fileExt := strings.ToLower(filepath.Ext(filePath))
				if fileExt == ".gmi" || fileExt == ".gemini" {
					result = gmitohtml.Convert([]byte(data), r.URL.String())
				} else if fileExt == ".htm" || fileExt == ".html" {
					result = data
				} else {
					result = data
					contentType = plainType
				}

				status := http.StatusOK
				w.Header().Set("Content-Type", contentType)
				w.WriteHeader(status)

				if r.Method == "HEAD" {
					return status, 0, serve.Log
				}
				w.Write(result)
				return status, int64(len(result)), serve.Log
			}
		}
	}

	http.NotFound(w, r)
	return http.StatusNotFound, -1, ""
}

type responseWriter struct {
	statusCode  int
	header      http.Header
	conn        *tls.Conn
	wroteHeader bool
}

func newResponseWriter(conn *tls.Conn) *responseWriter {
	return &responseWriter{
		header: http.Header{},
		conn:   conn,
	}
}

func (w *responseWriter) Header() http.Header {
	return w.header
}

func (w *responseWriter) Write(b []byte) (int, error) {
	if !w.wroteHeader {
		w.wroteHeader = true
		w.WriteHeader(http.StatusOK)
	}
	return w.conn.Write(b)
}

func (w *responseWriter) WriteHeader(statusCode int) {
	if w.wroteHeader {
		return
	}

	w.statusCode = statusCode

	statusText := http.StatusText(statusCode)
	if statusText == "" {
		statusText = "Unknown"
	}

	w.conn.Write([]byte(fmt.Sprintf("HTTP/1.1 %d %s\r\n", statusCode, statusText)))
	w.header.Write(w.conn)
	w.conn.Write([]byte("\r\n"))
}