#!/bin/bash

# vars
SELF="${BASH_SOURCE[0]}"
BASE_DIR=$(cd $(dirname "${BASH_SOURCE[0]}") && pwd -P)
BASE_DIR="${BASE_DIR:-$(pwd)}"
CONFIG="${BASE_DIR}/config.yaml"
DOCS_DIR="${BASE_DIR}/docs"
SOURCE_DIR="${BASE_DIR}/source"
TEMPLATE_DIR="${BASE_DIR}/templates"
TOOLS_DIR="${BASE_DIR}/tools"

# dependencies
MARKDOWN="${BASE_DIR}/tools/discount/markdown"
if [[ "${1}" == "--markdown" ]]; then  # TODO: remove ugly hack
    MARKDOWN="${2}"
fi
DEPS=("${MARKDOWN}")

# creates bash variables from yaml records
# https://gist.github.com/pkuczynski/8665367
function parse_yaml {
   local prefix=$2
   local s='[[:space:]]*' w='[a-zA-Z0-9_]*' fs=$(echo @|tr @ '\034')
   sed -ne "s|^\($s\)\($w\)$s:$s\"\(.*\)\"$s\$|\1$fs\2$fs\3|p" \
        -e "s|^\($s\)\($w\)$s:$s\(.*\)$s\$|\1$fs\2$fs\3|p"  $1 |
   awk -F$fs '{
      indent = length($1)/2;
      vname[indent] = $2;
      for (i in vname) {if (i > indent) {delete vname[i]}}
      if (length($3) > 0) {
         vn=""; for (i=0; i<indent; i++) {vn=(vn)(vname[i])("_")}
         printf("%s%s%s=\"%s\"\n", "'$prefix'",vn, $2, $3);
      }
   }'
}

# checks for required external tools
function check_dependencies {  # takes 1 argument
    DEPS=("${1}");
    ERROR=false
    for DEP in ${DEPS[@]}; do
        if echo "${DEP}" | grep '/' >/dev/null 2>&1 && [[ ! -x "${DEP}" ]]; then
            ERROR=true
        elif ! hash "${DEP}" >/dev/null 2>&1; then
            ERROR=true
        fi
    done
    if [[ "${ERROR}" == true ]]; then
        echo "Error: Unable to find command '${DEP#$BASE_DIR/}'." >&2
        return 1
    fi
}

# builds document(s) from a single source file
function build_source {

    local SOURCE YAML META_Title META_Project META_Project_URL META_Project_Version META_Language META_Language_Code META_Text_Encoding META_Authors META_Copyright META_License META_License_URL
    SOURCE="${1}"
    DEST="${SOURCE%.markdown}"
    DEST_NAME="${DEST##*/}"

    # check for yaml header
    META=false
    if head -n 1 "${SOURCE}" | grep '^---$' >/dev/null 2>&1; then
        META=true
    fi
    if [[ "${META}" == true ]]; then
        # split yaml and markdown
        awk '{ drop = 0; } /^---$/ { if (NR==1) { drop = 1 } else if (NR>1) { exit } else { drop = 0; next } } drop == 0 { print }' "${SOURCE}" > "${DEST}.yaml"
        mv "${SOURCE}" "${DEST}.markdown.temp"
        tail -n +$(wc -l "${DEST}.yaml" | awk '{ print $1+3 }') "${DEST}.markdown.temp" > "${SOURCE}"
        rm -f "${DEST}.markdown.temp"
        # parse yaml
        eval $(parse_yaml "${DEST}.yaml" "META_")
    fi

    # generate document using template
    DOCUMENT_Content="${DEST}.html.temp"
    "${MARKDOWN}" -fdlextra -ffencedcode -ffootnote -fgithubtags "${SOURCE}" > "${DOCUMENT_Content}"
    cp "${TEMPLATE_Document}" "${DEST}.html"
    if [[ "${DEST_NAME}" == "license" ]] || [[ "${DEST_NAME}" == "license-summary" ]]; then
        sed -E \
        -e 's|{{[ ]*template\.header[ ]*}}||g' \
        -e 's|{{[ ]*template\.footer[ ]*}}||g' \
        -i .sedbak "${DEST}.html"
    fi
    sed -E \
    -e '/{{[ ]*template\.header[ ]*}}/r '"${TEMPLATE_Header}"'' -e '/{{[ ]*template\.header[ ]*}}/d' \
    -e '/{{[ ]*document\.content[ ]*}}/r '"${DOCUMENT_Content}"'' -e '/{{[ ]*document\.content[ ]*}}/d' \
    -e '/{{[ ]*template\.footer[ ]*}}/r '"${TEMPLATE_Footer}"'' -e '/{{[ ]*template\.footer[ ]*}}/d' \
    -i .sedbak "${DEST}.html"
    sed -E \
    -e 's|{{[ ]*meta\.title[ ]*}}|'"${META_Title:-}"'|g' \
    -e 's|{{[ ]*meta\.project[ ]*}}|'"${META_Project:-}"'|g' \
    -e 's|{{[ ]*meta\.project-url[ ]*}}|'"${META_Project_URL:-}"'|g' \
    -e 's|{{[ ]*meta\.project-version[ ]*}}|'"${META_Project_Version:-}"'|g' \
    -e 's|{{[ ]*meta\.language[ ]*}}|'"${META_Language:-}"'|g' \
    -e 's|{{[ ]*meta\.language-code[ ]*}}|'"${META_Language_Code:-}"'|g' \
    -e 's|{{[ ]*meta\.text-encoding[ ]*}}|'"${META_Text_Encoding:-}"'|g' \
    -e 's|{{[ ]*meta\.authors[ ]*}}|'"${META_Authors:-}"'|g' \
    -e 's|{{[ ]*meta\.copyright[ ]*}}|'"${META_Copyright:-}"'|g' \
    -e 's|{{[ ]*meta\.license[ ]*}}|'"${META_License:-}"'|g' \
    -e 's|{{[ ]*meta\.license-abbr[ ]*}}|'"${META_License_Abbr:-}"'|g' \
    -e 's|{{[ ]*meta\.license-url[ ]*}}|'"${META_License_URL:-}"'|g' \
    -e 's|{{[ ]*base\.relpath[ ]*}}|'"${BASE_RELPATH:-}"'|g' \
    -i .sedbak "${DEST}.html"

    # clean up
    rm -f "${DEST}.markdown"
    rm -f "${DEST}.yaml"
    rm -f "${DEST}.html.temp"
    rm -f "${DEST}.html.sedbak"

}

# base directory (absolute)
cd "${BASE_DIR}"

# check deps
check_dependencies "${DEPS[@]}" || exit 1

# parse config
if [[ -e "${CONFIG}" ]]; then
    eval $(parse_yaml "${CONFIG}" "CONFIG_")
else
    echo "Configuration file not found." >&2
    exit 1
fi

# check template
TEMPLATE_DIR+="/${CONFIG_Template}"
if [[ ! -d "${TEMPLATE_DIR}" ]] || [[ ! -e "${TEMPLATE_DIR}/document.html" ]]; then
    echo "Template '${CONFIG_Template}' not found." >&2
    exit 1
fi

# template vars
TEMPLATE_Document="${TEMPLATE_DIR}/document.html"
TEMPLATE_Header="${TEMPLATE_DIR}/header.html"
TEMPLATE_Footer="${TEMPLATE_DIR}/footer.html"

# clean
rm -rf "${DOCS_DIR}"/*

# build
cp -R "${TEMPLATE_DIR}"/fonts "${TEMPLATE_DIR}"/style "${SOURCE_DIR}"/* "${DOCS_DIR}"/
SOURCES=($(find "${DOCS_DIR}" | sed 's/^\.\///' | grep -i '.markdown'))
for SOURCE in ${SOURCES[@]}; do
    BASE_RELPATH="${SOURCE#$DOCS_DIR/}"       # strip abs prefix
    BASE_RELPATH="${BASE_RELPATH//[^\/]}"     # leave only slashes
    BASE_RELPATH="${BASE_RELPATH//[\/]/../}"  # slashes to dirs
    build_source "${SOURCE}"
done

# done
exit 0