#!/bin/bash

CONTENT_DIR="content/"
FILTERS_DIR="filters/"
METADATA_DIR="metadata/"
TEMPLATES_DIR="templates/"
OUTPUT_DIR="output/"

CATEGORY_MAP=$(cat "$METADATA_DIR/categories.json")

get_filters() {
    filters_args=""

    mapfile -d $'\0' filters < <(find $FILTERS_DIR \
        -type f \
        -name "*.lua" ! -name ".*" \
        -print0)

    for file in "${filters[@]}"; do
        filters_args="$filters_args --lua-filter $file"
    done

    echo $filters_args
}

FILTERS=$(get_filters)

target_filename() {
    filename=$1
    filename=${filename#"$CONTENT_DIR"}
    if [ "${filename##*.}" = "md" ]; then
        filename="${filename%.md}.html"
    fi
    echo "$OUTPUT_DIR$filename"
}

target_url_rel() {
    basedir=$1
    filename=$2
    filename=$(realpath --relative-to="$basedir" "$filename")
    filename="${filename%.md}.html"
    if [ "${filename##*/}" = "index.html" ]; then
        filename=${filename%index.html}
    fi
    echo "$filename"
}

target_url_abs() {
    echo "/$(target_url_rel "$CONTENT_DIR" "$1")"
}

get_section() {
    filename=$1
    filename=${filename#"$CONTENT_DIR"}
    filename=${filename%.md}
    filename=$(echo "$filename" | cut -f1 -d /)
    echo "$filename"
}

get_subpages_basedir() {
    filename=$1
    if [ "${filename##*/}" = "index.md" ]; then
        filename=$(dirname "$filename")
    fi
    echo "$filename"
}

get_metadata() {
    basedir=$(get_subpages_basedir "$1")
    child_pages=()

    if [ -d "$basedir" ]; then
        mapfile -d $'\0' child_pages_1 < <(find $basedir/ \
            -type f \
            -name "*.md" ! -name "index.md" \
            -maxdepth 1 \
            -print0)

        mapfile -d $'\0' child_pages_2 < <(find $basedir/ \
            -type f \
            -name "index.md" \
            -mindepth 2 \
            -maxdepth 2 \
            -print0)

        child_pages=("${child_pages_1[@]}" "${child_pages_2[@]}")
    fi

    if [ ${#child_pages[@]} -ne 0 ]; then
        #echo -e "\033[0;90m[////////]\033[0m Child pages:"

        pages=$(echo "{}" | jq ". + { \
            all: [], \
            by_year: {} \
        }")

        categories="{}"

        for file in "${child_pages[@]}"; do
            #echo -e "\033[0;90m[////////]\033[0m   -  $file"

            url_rel=$(target_url_rel "$basedir" "$file")
            url_abs=$(target_url_abs "$file")

            metadata=$(pandoc "$file" \
                -f markdown \
                -t plain \
                --template scripts/metadata_tpl.json)

            date=$(echo "$metadata" | jq -r .date)
            category=$(echo "$metadata" | jq -r .category)
            category_name=$(echo "$CATEGORY_MAP" | jq -r .$category)

            metadata=$(echo "$metadata" | jq ". + { \
                url_rel: \"$url_rel\", \
                url_abs: \"$url_abs\" \
            }")

            pages=$(echo "$pages" | jq ".all += [ $metadata ]")

            if [ "$category" != "" ]; then
                categories=$(echo "$categories" | jq ". + { $category: \"$category_name\" }")
            fi

            if [ "$date" != "" ]; then
                date_year=$(date -d "$date" +%Y)
                #date_month=$(date -d "$date" +%m)
                #date_day=$(date -d "$date" +%d)

                pages=$(echo "$pages" | jq ".by_year.\"$date_year\" += [ $metadata ]")
            fi
        done

        pages=$(echo "$pages" \
            | jq ".all |= (sort_by(.date) | reverse) \
                | .by_year |= (to_entries | sort_by(.key) | reverse \
                    | .[].value |= (sort_by(.date) | reverse))")

        categories=$(echo "$categories" | jq ". | to_entries | sort_by(.key)")

        echo "{}" | jq ". + { \
            pages: $pages, \
            categories: $categories \
        }"
    fi
}

handle () {
    target=$(target_filename "$1")

    mkdir -p $(dirname "$target")

    if [ "${1#*.}" = "md" ]; then
        echo -e "\033[0;32m[COMPILE ]\033[0m $1 -> $target"

        is_home=false
        section=$(get_section "$1")

        if [ "$target" = "${OUTPUT_DIR}index.html" ]; then
            is_home=true
        fi

        subpages_meta_file=$(mktemp)

        # echo "$(get_metadata "$1")"
        echo "$(get_metadata "$1")" > "$subpages_meta_file"

        # echo $(pandoc "$1" \
        #     -f markdown \
        #     -t json)

        pandoc "$1" \
            -f markdown \
            -t html5 \
            --template "${TEMPLATES_DIR}base.html" \
            -o "$target" \
            --metadata "ishome"=$is_home \
            --metadata section=$section \
            --metadata "is$section" \
            --metadata-file metadata/metadata.yaml \
            --metadata-file "$subpages_meta_file" \
            $FILTERS
            # --lua-filter "filters/add_refs.lua"

        rm "$subpages_meta_file"
    else
        echo -e "\033[0;32m[COPY    ]\033[0m $1 -> $target"

        cp "$1" "$target"
    fi
}

if [ -z "$1" ]; then
    find "$CONTENT_DIR" \
        -type f \
        | while read file
            do
                handle "$file"
            done
elif [ "$1" = "all_md" ]; then
    find "$CONTENT_DIR" \
        -type f \
        -name "*.md" \
        | while read file
            do
                handle "$file"
            done
elif [ "$1" = "single" ]; then
    if [ -z "$2" ]; then
        echo -e "\033[0;31m[ERROR   ]\033[0m \"single\" operation requires file argument"
    else
        handle "$2"
    fi
elif [ "$1" = "delete" ]; then
    if [ -z "$2" ]; then
        echo -e "\033[0;31m[ERROR   ]\033[0m \"delete\" operation requires file argument"
    else
        TARGET=$(target_filename "$2")
        echo -e "\033[0;32m[DELETE  ]\033[0m $2 -> $TARGET"
        rm -rf $TARGET
    fi
else
    echo -e "\033[0;31m[ERROR   ]\033[0m Unknown operation: \"$1\""
fi