#!/bin/bash
set -euo pipefail

# --- Configuration ---
ARTICLES_DIR="blog/clanki"
BLOG_TEMPLATE="blog/template.html"
BLOG_INDEX="blog/index.html"
ARTICLE_TEMPLATE="blog/article-template.html"
HEADER_TEMPLATE_FILE="header-template.html"
FOOTER_TEMPLATE_FILE="footer-template.html"
BLOG_LEAD_TEXT="Tu zbiramo izkušnje, nasvete in dobre prakse z jezikovnega in medkulturnega področja. Namen je ustvariti prostor srečanja, učenja in navdiha."
ARCHIVE_HEADING_TEXT="Seznam vsebin"

PLACEHOLDER_TITLES=(
    "Pripravljamo nove vsebine"
    "Kratek vodič po delavnicah"
    "Naslednji koraki"
)
PLACEHOLDER_DATES=(
    "pomlad 2026"
    "pomlad 2026"
    "poletje 2026"
)
PLACEHOLDER_SUMMARIES=(
    "Razmišljanja o tem, kako navdušiti učence za medkulturne pogovore in skupinske projekte."
    "Kako strukturirati delavnico, ki vključuje starše, učitelje in otroke v enakopravnem dialogu."
    "Sledi blogu za nove prispevke in praktične nasvete."
)

PLACEHOLDER_IMAGE="/assets/images/blog/placeholder.webp"

check_jq_dependency() {
    if ! command -v jq &> /dev/null; then
        echo "Error: 'jq' is not installed. Please install it to run this script." >&2
        exit 1
    fi
}

find_article_files() {
    find "$ARTICLES_DIR" -maxdepth 1 -type f -name "*.html" | sort -r
}

extract_metadata() {
    local file="$1"
    local metadata_json
    metadata_json=$(perl -ne 'BEGIN{undef $/;} if (/<!--\s*(\{.*?})\s*-->/s) { print $1; exit }' "$file")

    if [ -z "${metadata_json:-}" ]; then
        echo ""
        return
    fi

    if ! echo "$metadata_json" | jq -e . &> /dev/null; then
        echo "Warning: Malformed JSON metadata in $file. Skipping article." >&2
        echo ""
        return
    fi

    echo "$metadata_json"
}

format_short_date() {
    local iso_date="$1"
    if [[ "$iso_date" =~ ^([0-9]{4})-([0-9]{2})-([0-9]{2})$ ]]; then
        printf "%s.%s.%s" "${BASH_REMATCH[3]}" "${BASH_REMATCH[2]}" "${BASH_REMATCH[1]}"
    else
        echo "$iso_date"
    fi
}

format_long_date() {
    local iso_date="$1"
    if [[ "$iso_date" =~ ^([0-9]{4})-([0-9]{2})-([0-9]{2})$ ]]; then
        local year="${BASH_REMATCH[1]}"
        local month="${BASH_REMATCH[2]}"
        local day="${BASH_REMATCH[3]}"
        local month_name
        case "$month" in
            01) month_name="januar" ;;
            02) month_name="februar" ;;
            03) month_name="marec" ;;
            04) month_name="april" ;;
            05) month_name="maj" ;;
            06) month_name="junij" ;;
            07) month_name="julij" ;;
            08) month_name="avgust" ;;
            09) month_name="september" ;;
            10) month_name="oktober" ;;
            11) month_name="november" ;;
            12) month_name="december" ;;
            *) month_name="$month" ;;
        esac
        printf "%s. %s %s" "$day" "$month_name" "$year"
    else
        echo "$iso_date"
    fi
}

get_article_image() {
    local file="$1"
    local filename=$(basename "$file" .html)
    echo "/assets/images/blog/${filename}/header.png"
}

generate_featured_article_html() {
    local file="$1"
    local metadata_json="$2"
    local title date image summary article_path long_date

    title=$(echo "$metadata_json" | jq -r '.title')
    date=$(echo "$metadata_json" | jq -r '.date')
    image=$(get_article_image "$file")
    summary=$(echo "$metadata_json" | jq -r '.summary // ""')
    article_path=$(basename "$file")
    long_date=$(format_long_date "$date")

    cat <<EOF
<article class="featured-article" data-aos="fade-up">
    <a href="/blog/clanki/${article_path}">
        <img src="${image}" alt="${title}">
        <div class="featured-article-content">
            <p class="article-date">${long_date}</p>
            <h2>${title}</h2>
            <p>${summary}</p>
        </div>
    </a>
</article>
EOF
}

generate_recent_article_card_html() {
    local file="$1"
    local metadata_json="$2"
    local title date image summary short_date article_path

    title=$(echo "$metadata_json" | jq -r '.title')
    date=$(echo "$metadata_json" | jq -r '.date')
    image=$(get_article_image "$file")
    summary=$(echo "$metadata_json" | jq -r '.summary // ""')
    article_path=$(basename "$file")
    short_date=$(format_short_date "$date")

    cat <<EOF
<article class="recent-card">
    <a href="/blog/clanki/${article_path}">
        <img src="${image}" alt="${title}">
        <h3>${title}</h3>
        <p class="article-date">${short_date}</p>
        <p>${summary}</p>
    </a>
</article>
EOF
}

generate_archive_list_item_html() {
    local file="$1"
    local metadata_json="$2"
    local title date short_date article_path

    title=$(echo "$metadata_json" | jq -r '.title')
    date=$(echo "$metadata_json" | jq -r '.date')
    article_path=$(basename "$file")
    short_date=$(format_short_date "$date")

    cat <<EOF
<li><a href="/blog/clanki/${article_path}">${title}</a> - ${short_date}</li>
EOF
}

generate_placeholder_card_html() {
    local index="$1"
    local slot=$((index % ${#PLACEHOLDER_TITLES[@]}))
    local title="${PLACEHOLDER_TITLES[$slot]}"
    local date="${PLACEHOLDER_DATES[$slot]}"
    local summary="${PLACEHOLDER_SUMMARIES[$slot]}"

    cat <<EOF
<article class="recent-card placeholder-card">
    <a href="#">
        <img src="${PLACEHOLDER_IMAGE}" alt="${title}">
        <h3>${title}</h3>
        <p class="article-date">${date}</p>
        <p>${summary}</p>
    </a>
</article>
EOF
}

check_template_file() {
    local file="$1"
    if [ ! -f "$file" ]; then
        echo "Error: Template file '$file' does not exist." >&2
        exit 1
    fi
}

check_template_file "$BLOG_TEMPLATE"
check_template_file "$ARTICLE_TEMPLATE"
check_template_file "$HEADER_TEMPLATE_FILE"
check_template_file "$FOOTER_TEMPLATE_FILE"

check_jq_dependency

ALL_ARTICLE_FILES=$(find_article_files)
VALID_ARTICLE_ENTRIES=()

for file in $ALL_ARTICLE_FILES; do
    filename=$(basename "$file")
    if [[ "$filename" =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}-.*\.html$ ]]; then
        metadata=$(extract_metadata "$file")
        if [ -z "${metadata:-}" ]; then
            continue
        fi
        article_date=$(echo "$metadata" | jq -r '.date // empty')
        if [ -z "$article_date" ]; then
            echo "Warning: Missing date in $file. Skipping article." >&2
            continue
        fi
        VALID_ARTICLE_ENTRIES+=("${article_date}|${file}")
    else
        echo "Warning: Invalid filename format for $file. Expected YYYY-MM-DD-*.html. Skipping article." >&2
    fi
done

if [ "${#VALID_ARTICLE_ENTRIES[@]}" -eq 0 ]; then
    echo "No valid article files found in $ARTICLES_DIR."
    exit 0
fi

SORTED_ENTRIES=$(printf "%s\n" "${VALID_ARTICLE_ENTRIES[@]}" | LC_ALL=C sort -t'|' -k1,1r -k2,2)

FEATURED_ARTICLE_HTML=""
RECENT_ARTICLES_HTML=""
ARCHIVE_HTML=""

ARTICLE_COUNT=0
RECENT_COUNT=0
PLACEHOLDER_INDEX=0

while IFS='|' read -r _ file; do
    metadata=$(extract_metadata "$file")
    if [ -z "${metadata:-}" ]; then
        continue
    fi

    if [ "$ARTICLE_COUNT" -eq 0 ]; then
        FEATURED_ARTICLE_HTML=$(generate_featured_article_html "$file" "$metadata")
    elif [ "$ARTICLE_COUNT" -le 3 ]; then
        RECENT_ARTICLES_HTML+=$'\n'"$(generate_recent_article_card_html "$file" "$metadata")"
        RECENT_COUNT=$((RECENT_COUNT + 1))
    fi
    
    # Add ALL articles to archive list
    ARCHIVE_HTML+=$'\n'"$(generate_archive_list_item_html "$file" "$metadata")"

    ARTICLE_COUNT=$((ARTICLE_COUNT + 1))
done <<< "$SORTED_ENTRIES"

if [ "$RECENT_COUNT" -lt 3 ]; then
    for ((i=RECENT_COUNT; i<3; i++)); do
        RECENT_ARTICLES_HTML+=$'\n'"$(generate_placeholder_card_html "$PLACEHOLDER_INDEX")"
        PLACEHOLDER_INDEX=$((PLACEHOLDER_INDEX + 1))
    done
fi

if [ -z "${FEATURED_ARTICLE_HTML:-}" ]; then
    echo "Warning: No featured article generated." >&2
fi

export FEATURED_ARTICLE_HTML
export RECENT_ARTICLES_HTML
export ARCHIVE_HTML
export BLOG_TEMPLATE
export BLOG_INDEX
export ARTICLE_TEMPLATE
export HEADER_TEMPLATE_FILE
export FOOTER_TEMPLATE_FILE
export BLOG_LEAD_TEXT
export ARCHIVE_HEADING_TEXT

python3 <<'PY'
import os
from pathlib import Path

template = Path(os.environ["BLOG_TEMPLATE"]).read_text()
template = template.replace("__HEADER_CONTENT__", Path(os.environ["HEADER_TEMPLATE_FILE"]).read_text())
template = template.replace("__NAJNOVEJSI_CLANEK__", os.environ.get("FEATURED_ARTICLE_HTML", ""))
template = template.replace("__CAKAJOCI_CLANKI__", os.environ.get("RECENT_ARTICLES_HTML", ""))
template = template.replace("__ARHIV_SEZNAM__", os.environ.get("ARCHIVE_HTML", ""))
template = template.replace("__BLOG_LEAD__", os.environ.get("BLOG_LEAD_TEXT", ""))
template = template.replace("__ARCHIVE_HEADING__", os.environ.get("ARCHIVE_HEADING_TEXT", ""))
template = template.replace("__FOOTER_CONTENT__", Path(os.environ["FOOTER_TEMPLATE_FILE"]).read_text())
Path(os.environ["BLOG_INDEX"]).write_text(template)
PY

echo "Blog page generated successfully at $BLOG_INDEX"