#!/bin/bash

if [ $# -lt 1 ]; then
    echo "Usage: $0 SCENEID" >&2
    exit 1
fi

mypath="$( dirname $0 )"
sceneid="$1"
scenepath="$mypath/../scenes/$sceneid"
scene="$( < "$scenepath" )"

spacecont="[Press Space to continue]"
setval="$mypath/setval"
getval="$mypath/getval"

getconf()
{
    grep -m 1 "^$1 " <<< "$cdata" \
        | cut -d' ' -f2-
}

setscene()
{
    $setval _scene $1
}

parsevals()
{
    local data=$( cat )
    local vals=$( grep -o '%[a-zA-Z0-9]\+%' <<< "$data" )
    local pre=$1
    local post=$2

    local replace=''
    for val in $vals; do
        result=$( $getval $( sed 's/^%\|%$//g' <<< "$val" ) 2>/dev/null )
        replace="$replace;s/$val/$pre$result$post/"
    done

    sed "$replace" <<< "$data"
    echo
}

if [ ! -r "$scenepath" ]; then
    echo "Scene not found" >&2
    exit 2
fi

# all configuration options appear before the first empty line
cdata=$(
    awk '/^$/ { stop=1 } { if ( !stop ) print }' \
    <<< "$scene"
)

type="$( getconf TYPE )"
nextscene="$( getconf NEXT )"

# clear the screen to prepare to render the scene
clear

# output the story, as identified by the STORY line, using a pager (less) in the
# event that the page is too long for the terminal
awk '/STORY/ {
        found=1;
        getline
    }
    { if ( found ) print }
    END { print "" }
    ' <<< "$scene" \
    | parsevals \
    | less -EF

inputs=$(
    awk '/INPUT/,/^$/ {
        if ( ! $0 ) {
            print ""
        } else {
            printf "%s ", $0
        }
    }
    ' <<< "$scene"
)
IFS="
"
for inline in $inputs; do
    dest="$( cut -d' ' -f2 <<< "$inline" )"
    text="$( cut -d' ' -f3- <<< "$inline" )"

    echo "$text"
    echo

    input=''
    while [ ! "$input" ]; do
        read -p '> ' input
    done

    $setval "$dest" "$input"
done


branches=$( awk '/^BRANCH /' <<< "$scene" | parsevals \" \" )
IFS="
"
for branch in $branches; do
    dest=$( cut -d' ' -f2 <<< "$branch" )
    teststr=$( cut -d' ' -f3- <<< "$branch" )

    eval test $teststr && {
        nextscene="$dest"

        # don't check any other branches
        break
    }
done

# input handling is defined by the scene type
case "$type" in
    action)
        read -p '> ' input
        ;;

    trans|transition)
        read -s -d ' ' -p "$spacecont"
        echo
        ;;

    end)
        read -s -d ' ' -p '[Press Space to end]'
        exit 100
        ;;

    input)
        # input should have already been done
        ;;

    *)
        echo "WARNING: Unknown scene type: $type" >&2
        read -s -d ' '
        ;;
esac

# if no next scene was provided, then there's nothing we can do
if [ ! "$nextscene" ]; then
    setscene err-scene
    exit 1
fi

# set the next scene (this is persistent, allowing the user to quit at any time)
setscene "$nextscene"