#!/usr/bin/env bash
set -euo pipefail

# === METADATA ===
SCRIPT_NAME="$(basename "$0")"
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
SKILL_ROOT="$(dirname "$SCRIPT_DIR")"

# === CONFIGURATION ===
: "${OUTPUT_DIR:=$SKILL_ROOT/outputs}"
: "${BACKUP_SOURCES:=}"
: "${BACKUP_EXCLUDES:=.git,node_modules,target,dist,outputs}"

# === FUNCTIONS ===
log_info()  { echo "[INFO]  $(date -Iseconds) $*"; }
log_warn()  { echo "[WARN]  $(date -Iseconds) $*" >&2; }
log_error() { echo "[ERROR] $(date -Iseconds) $*" >&2; }
die()       { log_error "$@"; exit 1; }

check_tool() {
    local tool="$1"
    if command -v "$tool" &>/dev/null; then
        log_info "Found: $tool ($(command -v "$tool"))"
        return 0
    else
        log_warn "Missing: $tool"
        return 1
    fi
}

check_b3sum() {
    if command -v b3sum &>/dev/null; then
        log_info "Found: b3sum ($(command -v b3sum))"
        return 0
    elif command -v blake3 &>/dev/null; then
        log_info "Found: blake3 ($(command -v blake3))"
        return 0
    else
        log_warn "Missing: b3sum or blake3"
        return 1
    fi
}

main() {
    log_info "Starting $SCRIPT_NAME..."
    mkdir -p "$OUTPUT_DIR"

    local missing=0

    log_info "=== Required Tools ==="
    check_tool tar || ((missing++))
    check_tool gzip || ((missing++))
    check_tool age || ((missing++))
    check_b3sum || ((missing++))
    check_tool stat || ((missing++))
    check_tool find || ((missing++))

    log_info "=== Backup Sources ==="
    if [[ -z "$BACKUP_SOURCES" ]]; then
        log_warn "BACKUP_SOURCES not set (required for backup)"
    else
        IFS=',' read -r -a sources <<< "$BACKUP_SOURCES"
        for src in "${sources[@]}"; do
            # Expand ~ if present
            src="${src/#\~/$HOME}"
            if [[ -e "$src" ]]; then
                log_info "Source exists: $src"
            else
                log_warn "Source missing: $src"
            fi
        done
    fi

    log_info "=== Encryption Files ==="
    if [[ -n "${AGE_RECIPIENT_FILE:-}" ]]; then
        if [[ -f "$AGE_RECIPIENT_FILE" ]]; then
            log_info "AGE_RECIPIENT_FILE exists: $AGE_RECIPIENT_FILE"
        else
            log_warn "AGE_RECIPIENT_FILE missing: $AGE_RECIPIENT_FILE"
        fi
    else
        log_warn "AGE_RECIPIENT_FILE not set (required for encryption)"
    fi

    if [[ -n "${AGE_IDENTITY_FILE:-}" ]]; then
        if [[ -f "$AGE_IDENTITY_FILE" ]]; then
            log_info "AGE_IDENTITY_FILE exists: $AGE_IDENTITY_FILE"
        else
            log_warn "AGE_IDENTITY_FILE missing: $AGE_IDENTITY_FILE"
        fi
    else
        log_warn "AGE_IDENTITY_FILE not set (required for restore drill)"
    fi

    log_info "=== Disk Space ==="
    local avail
    avail=$(df -P "$OUTPUT_DIR" | awk 'NR==2 {print $4}')
    log_info "Available space in $OUTPUT_DIR: $((avail / 1024)) MB"

    log_info "=== Parameters ==="
    log_info "NODE_NAME=${NODE_NAME:-node-a}"
    log_info "BACKUP_LABEL=${BACKUP_LABEL:-manual}"
    log_info "BACKUP_EXCLUDES=$BACKUP_EXCLUDES"
    log_info "DRY_RUN=${DRY_RUN:-1} (apply scripts require DRY_RUN=0)"

    if [[ $missing -gt 0 ]]; then
        die "Missing $missing required tools. Install them before proceeding."
    fi

    log_info "Preflight OK."
    log_info "Completed $SCRIPT_NAME"
}

[[ "${BASH_SOURCE[0]}" == "$0" ]] && main "$@"