#!/usr/bin/env bash

declare -A clients http_codes=(
  [200]=OK [400]="Bad Request" [403]=Forbidden
  [404]="Not Found" [405]="Method Not Allowed"
)

enable -f "${SHERVER_SO_PATH-.}"/sherver.so sherver_{bind,select,accept}

if ! sherver-bind -p 8080 -h 0.0.0.0 -v server_fd; then
  exit
fi

while true; do
  if ! sherver-select -iv ready_fds "$server_fd" "${!clients[@]}"; then
    continue
  fi

  for fd in "${ready_fds[@]}"; do
    if (( fd == server_fd )) && sherver-accept -v client_info "$server_fd"; then
      declare -A __client_{req,resp}_"${client_info[0]}"_ 
      declare -n client_req=__client_req_${client_info[0]}_
      client_req[ip]=${client_info[1]}
      client_req[port]=${client_info[2]}
      clients[${client_info[0]}]=0
    else
      declare -n client_req=__client_req_${fd}_
      declare -n client_resp=__client_resp_${fd}_

      if ! IFS= read -ru "$fd" line || (( ! ${#line} )); then
        unset "__client_"{req,resp}"_${fd}_" "clients[$fd]"
        exec {fd}>&-
      else
        (( clients[$fd] += ${#line} + 1 ))
        line=${line%$'\r'}

        if [[ ! -v client_req[method] ]]; then
          read -ra req_line <<< "$line"
          client_req[method]=${req_line[0],,}
          client_req[req-file]=${req_line[1]}
          client_req[version]=${req_line[2]-HTTP/1.0}

          case ${client_req[method]} in
          get)
            client_resp[has-payload]=yes
            ;;
          head)
            client_resp[has-payload]=no
            ;;
          *)
            client_req[error]=yes
            client_resp[code]=405
          esac

          if [[ ${client_req[req-file]} = /* ]]; then
            client_req[real-file]=.${client_req[req-file]}

            if [[ ${client_req[req-file]} = */ ]]; then
              client_req[real-file]+=index.html
            elif [[ -d client_req[real-file] ]]; then
              client_req[real-file]+=/index.html
            fi
          else
            client_req[error]=yes
            client_resp[code]=400
          fi

          if [[ ${client_req[error]} != yes ]]; then
            if [[ -f ${client_req[real-file]} ]]; then
              if [[ -r ${client_req[real-file]} ]]; then
                client_resp[code]=200
              else
                client_req[error]=yes
                client_resp[code]=403
              fi
            else
              client_req[error]=yes
              client_resp[code]=404
            fi
          fi
        elif [[ $line = *": "* ]]; then
          hdr_key=${line%%:*} hdr_key=${hdr_key,,}
          client_req[hdr-$hdr_key]=${line#*: }
        elif [[ -z $line ]]; then
          req_host=${client_req[hdr-host]-"$HOSTNAME"}
          ver=${client_req[version]} code=${client_resp[code]}

          if [[ ${client_req[error]} = yes ]]; then
            client_req[real-file]=./error.html
            client_resp[has-payload]=yes
          fi

          payload=$(<"${client_req[real-file]}")
          client_resp[hdr-Content-Length]=${#payload}

          case ${client_req[req-file]} in
          *.html)
            client_resp[hdr-Content-Type]=text/html
            ;;
          *.txt)
            client_resp[hdr-Content-Type]=text/plain
            ;;
          *)
            client_resp[hdr-Content-Type]=application/octet-stream
          esac

          printf -v 'client_resp[hdr-Date]' '%(%Y-%m-%d %H:%M:%S)T' -1
          printf '%s %d %s\r\n' "$ver" "$code" "${http_codes[$code]}" >&"$fd"

          for hdr in "${!client_resp[@]}"; do
            if [[ $hdr = hdr-* ]]; then
              printf '%s: %s\r\n' "${hdr#hdr-}" "${client_resp[$hdr]}" >&"$fd"
            fi
          done

          printf '\r\n' >&"$fd"

          if [[ ${client_resp[has-payload]} = yes ]]; then
            printf %s "$payload" >&"$fd"
          fi

          printf '[%s] %s has requested http://%s%s (%s)\n' "${client_resp[hdr-Date]}" "${client_req[ip]}" "$req_host" "${client_req[req-file]}" "${client_req[real-file]}"
        fi
      fi
    fi
  done
done