#!/usr/bin/env bash

#########################################################################################
#### sitemap-validator.sh — Validate Hugo sitemap URLs, meta tags, and content parity ####
#### Checks each URL for HTTP 200, duplicates, missing meta tags, and compares        ####
#### sitemap entries against local Hugo content files                                 ####
####                                                                                  ####
#### Author: Phil Connor                                                              ####
#### Contact: contact@mylinux.work                                                    ####
#### License: MIT                                                                     ####
#### Version 1.1                                                                      ####
####                                                                                  ####
#### Usage:                                                                           ####
####   ./sitemap-validator.sh https://example.com/sitemap.xml                         ####
####   ./sitemap-validator.sh --file public/sitemap.xml --local-dir content            ####
####   ./sitemap-validator.sh --help                                                  ####
####                                                                                  ####
#### See --help for all options.                                                      ####
#########################################################################################

set -euo pipefail

# ── Defaults ──────────────────────────────────────────────────────────
SITEMAP_URL="${SITEMAP_URL:-}"
SITEMAP_FILE=""
LOCAL_DIR=""
PUBLIC_DIR=""
CHECK_META="${CHECK_META:-true}"
PARALLEL="${PARALLEL:-5}"
VERBOSE="${VERBOSE:-false}"
COLOR="${COLOR:-auto}"
BASE_URL=""

# ── State ─────────────────────────────────────────────────────────────
SCRIPT_NAME="$(basename "$0")"
readonly SCRIPT_NAME
TMPDIR_WORK=""
COUNT_TOTAL=0
COUNT_OK=0
COUNT_BROKEN=0
COUNT_MISSING_META=0
COUNT_DUPLICATES=0
COUNT_ORPHAN=0

# ── Colors ────────────────────────────────────────────────────────────
setup_colors() {
    if [[ "$COLOR" == "never" ]]; then
        RED="" GREEN="" YELLOW="" CYAN="" BOLD="" DIM="" RESET=""
        return
    fi
    if [[ "$COLOR" == "always" ]] || [[ -t 1 ]]; then
        RED='\033[0;31m'
        GREEN='\033[0;32m'
        YELLOW='\033[0;33m'
        CYAN='\033[0;36m'
        BOLD='\033[1m'
        DIM='\033[2m'
        RESET='\033[0m'
    else
        RED="" GREEN="" YELLOW="" CYAN="" BOLD="" DIM="" RESET=""
    fi
}

# ── Logging ───────────────────────────────────────────────────────────
log()     { echo -e "${CYAN}[INFO]${RESET} $*"; }
warn()    { echo -e "${YELLOW}[WARN]${RESET} $*" >&2; }
err()     { echo -e "${RED}[ERROR]${RESET} $*" >&2; }
verbose() { if [[ "$VERBOSE" == "true" ]]; then echo -e "${DIM}[DEBUG]${RESET} $*"; fi; }

# ── Helpers ───────────────────────────────────────────────────────────
section_header() {
    echo ""
    echo -e "  ${BOLD}${CYAN}── $1 ──${RESET}"
    echo ""
}

cleanup() {
    if [[ -n "$TMPDIR_WORK" && -d "$TMPDIR_WORK" ]]; then
        rm -rf "$TMPDIR_WORK"
    fi
}
trap cleanup EXIT

fetch_sitemap() {
    local dest="$1"
    if [[ -n "$SITEMAP_FILE" ]]; then
        if [[ ! -f "$SITEMAP_FILE" ]]; then
            err "Sitemap file not found: $SITEMAP_FILE"
            exit 1
        fi
        cp "$SITEMAP_FILE" "$dest"
    elif [[ -n "$SITEMAP_URL" ]]; then
        verbose "Fetching sitemap from $SITEMAP_URL"
        if ! curl -fsSL --max-time 30 "$SITEMAP_URL" -o "$dest" 2>/dev/null; then
            err "Failed to fetch sitemap: $SITEMAP_URL"
            exit 1
        fi
    else
        err "No sitemap URL or file specified"
        exit 1
    fi
}

extract_urls() {
    local sitemap_file="$1"
    grep -oP '<loc>\K[^<]+' "$sitemap_file" || true
}

check_duplicates() {
    local url_file="$1"
    local dupes
    dupes=$(sort "$url_file" | uniq -d)
    if [[ -n "$dupes" ]]; then
        section_header "Duplicate URLs"
        while IFS= read -r url; do
            local count
            count=$(grep -cF "$url" "$url_file" || true)
            echo -e "  ${RED}✗${RESET} ${url} (${count} occurrences)"
            COUNT_DUPLICATES=$((COUNT_DUPLICATES + 1))
        done <<< "$dupes"
    else
        verbose "No duplicate URLs found"
    fi
}

url_to_local_path() {
    local url="$1"
    local path
    path=$(echo "$url" | sed -E 's|https?://[^/]+||')
    path="${path%/}"
    echo "${PUBLIC_DIR}${path}/index.html"
}

check_meta_tags() {
    local html_file="$1"
    local warnings=""

    if ! grep -qi '<title>' "$html_file"; then
        warnings="${warnings}missing-title,"
    fi
    if ! grep -qi 'name="description"' "$html_file"; then
        warnings="${warnings}missing-description,"
    fi
    if ! grep -qi 'rel="canonical"' "$html_file"; then
        warnings="${warnings}missing-canonical,"
    fi
    if ! grep -qi 'og:title' "$html_file"; then
        warnings="${warnings}missing-og-title,"
    fi

    echo "${warnings%,}"
}

check_url_local() {
    local url="$1"
    local results_dir="$2"
    local safe_name
    safe_name=$(echo "$url" | md5sum | cut -d' ' -f1)
    local result_file="${results_dir}/${safe_name}"

    local html_file
    html_file=$(url_to_local_path "$url")

    if [[ -f "$html_file" ]]; then
        echo "ok" > "$result_file"

        if [[ "$CHECK_META" == "true" ]]; then
            local warnings
            warnings=$(check_meta_tags "$html_file")
            if [[ -n "$warnings" ]]; then
                echo "meta:${warnings}" > "$result_file"
            fi
        fi
    else
        echo "broken:missing" > "$result_file"
    fi
    echo "$url" >> "$result_file"
}

check_url_remote() {
    local url="$1"
    local results_dir="$2"
    local safe_name
    safe_name=$(echo "$url" | md5sum | cut -d' ' -f1)
    local result_file="${results_dir}/${safe_name}"
    local body_file="${results_dir}/${safe_name}.body"

    local http_code
    http_code=$(curl -sL --max-time 10 -o "$body_file" -w '%{http_code}' "$url" 2>/dev/null) || http_code="000"

    if [[ "$http_code" == "200" ]]; then
        echo "ok" > "$result_file"

        if [[ "$CHECK_META" == "true" && -s "$body_file" ]]; then
            local warnings
            warnings=$(check_meta_tags "$body_file")
            if [[ -n "$warnings" ]]; then
                echo "meta:${warnings}" > "$result_file"
            fi
        fi
    else
        echo "broken:${http_code}" > "$result_file"
    fi
    echo "$url" >> "$result_file"
    rm -f "$body_file"
}

check_urls_parallel() {
    local url_file="$1"
    local results_dir="$2"
    local check_fn="check_url_remote"

    if [[ -n "$PUBLIC_DIR" ]]; then
        check_fn="check_url_local"
    fi

    mkdir -p "$results_dir"

    local pids=()
    local running=0

    while IFS= read -r url; do
        [[ -z "$url" ]] && continue
        "$check_fn" "$url" "$results_dir" &
        pids+=($!)
        running=$((running + 1))

        if [[ "$running" -ge "$PARALLEL" ]]; then
            wait "${pids[0]}" 2>/dev/null || true
            pids=("${pids[@]:1}")
            running=$((running - 1))
        fi
    done < "$url_file"

    for pid in "${pids[@]}"; do
        wait "$pid" 2>/dev/null || true
    done
}

report_url_results() {
    local results_dir="$1"

    section_header "URL Check Results"

    for result_file in "$results_dir"/*; do
        [[ -f "$result_file" ]] || continue
        local status url
        status=$(head -1 "$result_file")
        url=$(tail -1 "$result_file")

        COUNT_TOTAL=$((COUNT_TOTAL + 1))

        if [[ "$status" == "ok" ]]; then
            COUNT_OK=$((COUNT_OK + 1))
            if [[ "$VERBOSE" == "true" ]]; then
                echo -e "  ${GREEN}✓${RESET} ${url}"
            fi
        elif [[ "$status" == broken:* ]]; then
            local code="${status#broken:}"
            COUNT_BROKEN=$((COUNT_BROKEN + 1))
            echo -e "  ${RED}✗${RESET} ${url} — HTTP ${code}"
        elif [[ "$status" == meta:* ]]; then
            local tags="${status#meta:}"
            COUNT_OK=$((COUNT_OK + 1))
            COUNT_MISSING_META=$((COUNT_MISSING_META + 1))
            echo -e "  ${YELLOW}⚠${RESET} ${url} — ${tags}"
        fi
    done
}

check_orphan_content() {
    local url_file="$1"

    if [[ -z "$LOCAL_DIR" ]]; then
        verbose "No --local-dir specified, skipping orphan check"
        return
    fi

    if [[ ! -d "$LOCAL_DIR" ]]; then
        warn "Content directory not found: $LOCAL_DIR"
        return
    fi

    if [[ -z "$BASE_URL" ]]; then
        BASE_URL=$(head -1 "$url_file" | grep -oP 'https?://[^/]+' || true)
        if [[ -z "$BASE_URL" ]]; then
            warn "Could not determine base URL — skipping orphan check"
            return
        fi
    fi

    section_header "Orphan Content (not in sitemap)"

    local found_orphan=false
    while IFS= read -r -d '' content_file; do
        local dir_name
        dir_name=$(dirname "$content_file")
        local rel_path="${dir_name#"$LOCAL_DIR"}"
        rel_path="${rel_path#/}"

        if [[ "$(basename "$content_file")" == "_index.md" ]]; then
            continue
        fi

        local expected_url="${BASE_URL}/${rel_path}/"
        expected_url="${expected_url//\/\///}"
        expected_url="${expected_url/:\//://}"

        local front_matter
        front_matter=$(sed -n '/^---$/,/^---$/p' "$content_file" 2>/dev/null | head -20)

        if echo "$front_matter" | grep -qi 'draft: *true'; then
            verbose "Skipping draft: $content_file"
            continue
        fi

        if ! grep -qF "$rel_path" "$url_file" 2>/dev/null; then
            echo -e "  ${YELLOW}⚠${RESET} ${content_file} → expected ${expected_url}"
            COUNT_ORPHAN=$((COUNT_ORPHAN + 1))
            found_orphan=true
        fi
    done < <(find "$LOCAL_DIR" -name "index.md" -print0 2>/dev/null)

    if [[ "$found_orphan" == "false" ]]; then
        echo -e "  ${GREEN}✓${RESET} All content files found in sitemap"
    fi
}

print_summary() {
    section_header "Summary"

    printf "  ${BOLD}%-24s${RESET} %d\n" "Total URLs:" "$COUNT_TOTAL"
    printf "  ${BOLD}%-24s${RESET} %b%d%b\n" "OK:" "$GREEN" "$COUNT_OK" "$RESET"
    printf "  ${BOLD}%-24s${RESET} %b%d%b\n" "Broken:" "$RED" "$COUNT_BROKEN" "$RESET"
    printf "  ${BOLD}%-24s${RESET} %b%d%b\n" "Missing meta tags:" "$YELLOW" "$COUNT_MISSING_META" "$RESET"
    printf "  ${BOLD}%-24s${RESET} %b%d%b\n" "Duplicate URLs:" "$YELLOW" "$COUNT_DUPLICATES" "$RESET"
    printf "  ${BOLD}%-24s${RESET} %b%d%b\n" "Orphan content files:" "$YELLOW" "$COUNT_ORPHAN" "$RESET"
    echo ""

    if [[ "$COUNT_BROKEN" -gt 0 || "$COUNT_DUPLICATES" -gt 0 ]]; then
        echo -e "  ${RED}${BOLD}FAIL${RESET} — issues found"
        return 1
    else
        echo -e "  ${GREEN}${BOLD}PASS${RESET} — sitemap looks good"
        return 0
    fi
}

# ══════════════════════════════════════════════════════════════════════
#                       USAGE
# ══════════════════════════════════════════════════════════════════════

usage() {
    cat <<EOF
${SCRIPT_NAME} — Validate Hugo sitemap URLs, meta tags, and content parity

USAGE:
  ${SCRIPT_NAME} [OPTIONS] <SITEMAP_URL>
  ${SCRIPT_NAME} --file sitemap.xml [OPTIONS]

OPTIONS:
  --file FILE           Read sitemap from local file instead of URL
                        Auto-detects public dir and checks local HTML files
  --public-dir DIR      Override public directory for local HTML checks
  --local-dir DIR       Hugo content directory for orphan detection
  --base-url URL        Override base URL for orphan content matching
  --parallel N          Max concurrent URL checks (default: ${PARALLEL})
  --no-meta             Skip meta tag checks
  --verbose             Enable debug output
  --no-color            Disable colored output
  --help                Show this help

ENVIRONMENT VARIABLES:
  SITEMAP_URL           Default sitemap URL if not passed as argument
  CHECK_META            Enable/disable meta checks (default: true)
  PARALLEL              Max concurrent checks (default: 5)
  COLOR                 Color mode: auto, always, never (default: auto)

EXAMPLES:
  # Validate remote sitemap
  ./${SCRIPT_NAME} https://example.com/sitemap.xml

  # Validate local build with content cross-reference
  ./${SCRIPT_NAME} --file public/sitemap.xml --local-dir content

  # Fast check — skip meta tag validation
  ./${SCRIPT_NAME} --no-meta https://example.com/sitemap.xml

  # High concurrency
  ./${SCRIPT_NAME} --parallel 20 https://example.com/sitemap.xml
EOF
}

# ══════════════════════════════════════════════════════════════════════
#                       ARGUMENT PARSING
# ══════════════════════════════════════════════════════════════════════

parse_args() {
    while [[ $# -gt 0 ]]; do
        case "$1" in
            --file)
                SITEMAP_FILE="$2"; shift 2 ;;
            --public-dir)
                PUBLIC_DIR="$2"; shift 2 ;;
            --local-dir)
                LOCAL_DIR="$2"; shift 2 ;;
            --base-url)
                BASE_URL="$2"; shift 2 ;;
            --parallel)
                PARALLEL="$2"; shift 2 ;;
            --no-meta)
                CHECK_META="false"; shift ;;
            --verbose)
                VERBOSE="true"; shift ;;
            --no-color)
                COLOR="never"; shift ;;
            --help|-h)
                setup_colors
                usage
                exit 0 ;;
            -*)
                err "Unknown option: $1"
                echo "Run ${SCRIPT_NAME} --help for usage" >&2
                exit 1 ;;
            *)
                SITEMAP_URL="$1"; shift ;;
        esac
    done
}

# ══════════════════════════════════════════════════════════════════════
#                       MAIN
# ══════════════════════════════════════════════════════════════════════

main() {
    parse_args "$@"
    setup_colors

    if [[ -z "$SITEMAP_URL" && -z "$SITEMAP_FILE" ]]; then
        err "No sitemap URL or file specified"
        echo "Run ${SCRIPT_NAME} --help for usage" >&2
        exit 1
    fi

    TMPDIR_WORK=$(mktemp -d)
    local sitemap_file="${TMPDIR_WORK}/sitemap.xml"
    local url_file="${TMPDIR_WORK}/urls.txt"
    local results_dir="${TMPDIR_WORK}/results"

    # Auto-detect public directory from --file path
    if [[ -n "$SITEMAP_FILE" && -z "$PUBLIC_DIR" ]]; then
        PUBLIC_DIR=$(cd "$(dirname "$SITEMAP_FILE")" && pwd)
        if [[ ! -d "${PUBLIC_DIR}/guides" && ! -d "${PUBLIC_DIR}/posts" ]]; then
            verbose "Auto-detected PUBLIC_DIR=${PUBLIC_DIR} but no content dirs found — falling back to remote"
            PUBLIC_DIR=""
        else
            verbose "Auto-detected PUBLIC_DIR=${PUBLIC_DIR}"
        fi
    fi

    local mode="remote"
    [[ -n "$PUBLIC_DIR" ]] && mode="local (${PUBLIC_DIR})"

    echo ""
    echo -e "${BOLD}Sitemap Validator${RESET}"
    echo -e "${DIM}Source: ${SITEMAP_URL:-$SITEMAP_FILE}${RESET}"
    echo -e "${DIM}Mode: ${mode} | Parallel: ${PARALLEL} | Meta check: ${CHECK_META}${RESET}"

    fetch_sitemap "$sitemap_file"
    extract_urls "$sitemap_file" > "$url_file"

    local url_count
    url_count=$(wc -l < "$url_file")
    if [[ "$url_count" -eq 0 ]]; then
        err "No URLs found in sitemap"
        exit 1
    fi
    log "Found ${url_count} URLs in sitemap"

    # Check for localhost
    if grep -qi 'localhost\|127\.0\.0\.1' "$url_file"; then
        warn "Sitemap contains localhost URLs — check your baseURL"
    fi

    check_duplicates "$url_file"
    check_urls_parallel "$url_file" "$results_dir"
    report_url_results "$results_dir"
    check_orphan_content "$url_file"
    print_summary
}

main "$@"