#!/usr/bin/env bash
#
# A simple, configurable HTTP server written in bash.
#
# See LICENSE for licensing information.
#
# Original author: Avleen Vig, 2012
# Reworked by:     Josh Cartwright, 2012

warn() { echo "WARNING: $@" >&2; }

recv() { echo "< $@" >&2; }
send() { echo "> $@" >&2;
         printf '%s\r\n' "$*"; }

[[ $UID = 0 ]] && warn "It is not recommended to run bashttpd as root."

DATE=$(date +"%a, %d %b %Y %H:%M:%S %Z")
declare -a RESPONSE_HEADERS=(
      "Date: $DATE"
   "Expires: $DATE"
    "Server: Slash Bin Slash Bash"
)

add_response_header() {
   RESPONSE_HEADERS+=("$1: $2")
}

declare -a HTTP_RESPONSE=(
   [200]="OK"
   [400]="Bad Request"
   [403]="Forbidden"
   [404]="Not Found"
   [405]="Method Not Allowed"
   [500]="Internal Server Error"
)

send_response() {
   local code=$1
   send "HTTP/1.0 $1 ${HTTP_RESPONSE[$1]}"
   for i in "${RESPONSE_HEADERS[@]}"; do
      send "$i"
   done
   send
   while read -r line; do
      send "$line"
   done
}

send_response_ok_exit() { send_response 200; exit 0; }

fail_with() {
   send_response "$1" <<< "$1 ${HTTP_RESPONSE[$1]}"
   exit 1
}
serve_static_string() {
   add_response_header "Content-Type" "text/plain;charset=utf-8"
   send_response_ok_exit <<< "$1"
}

where () {
    h="$(dirname "$0")"
    # If $h isnt absolute, prepend working dir
    if [[ ! "${h:0:1}" = "/" ]] ; then
        h="$(pwd)/$(dirname "$0")"
    fi
    h="$(realpath "$h")"
    echo "$h"
}

main () {
    # Request uri must be a relative path from the exercices/corriges directory
    [ -x "$REQUEST_URI" ] || [ ! -d "$REQUEST_URI" ] || fail_with 404
    here="$(where)"
    path="$(realpath "$here/exercices/corriges/$REQUEST_URI")"
    [[ "$path" = "$here"* ]] || fail_with 404
    serve_static_string "$(basename "$path" | cut -d '.' -f 1) : $(bash "$path" 2>&1 && echo Ok || echo 'Non validé')"
}

# Request-Line HTTP RFC 2616 $5.1
read -r line || fail_with 400

# strip trailing CR if it exists
line=${line%%$'\r'}
recv "$line"

read -r REQUEST_METHOD REQUEST_URI REQUEST_HTTP_VERSION <<<"$line"

[ -n "$REQUEST_METHOD" ] && \
[ -n "$REQUEST_URI" ] && \
[ -n "$REQUEST_HTTP_VERSION" ] \
   || fail_with 400

# Only GET is supported at this time
[ "$REQUEST_METHOD" = "GET" ] || fail_with 405

declare -a REQUEST_HEADERS

while read -r line; do
   line=${line%%$'\r'}
   recv "$line"

   # If we've reached the end of the headers, break.
   [ -z "$line" ] && break

   REQUEST_HEADERS+=("$line")
done

main

fail_with 500