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

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

# === CONFIGURATION ===
: "${NODE_NAME:=node-a}"
: "${BACKUP_LABEL:=manual}"
: "${OUTPUT_DIR:=$SKILL_ROOT/outputs}"
: "${BACKUP_SOURCES:=}"
: "${BACKUP_EXCLUDES:=.git,node_modules,target,dist,outputs}"
: "${DRY_RUN:=1}"
: "${REQUIRE_CONFIRM:=1}"
: "${CONFIRM_PHRASE:=I UNDERSTAND THIS WILL CREATE AND ENCRYPT BACKUPS}"

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

b3_file() {
    if command -v b3sum &>/dev/null; then
        b3sum "$1" | awk '{print $1}'
    else
        blake3 "$1"
    fi
}

require_confirm() {
    [[ "$DRY_RUN" == "0" ]] || die "DRY_RUN=$DRY_RUN (set DRY_RUN=0 to apply)."

    if [[ "$REQUIRE_CONFIRM" == "1" ]]; then
        echo ""
        echo "CONFIRMATION REQUIRED"
        echo "Type the phrase exactly to continue:"
        echo "  $CONFIRM_PHRASE"
        read -r input
        [[ "$input" == "$CONFIRM_PHRASE" ]] || die "Confirmation phrase mismatch; aborting."
    fi
}

json_array() {
    # Convert comma-separated string to JSON array
    local input="$1"
    local first=true
    echo -n "["
    IFS=',' read -r -a items <<< "$input"
    for item in "${items[@]}"; do
        if [[ "$first" == "true" ]]; then
            first=false
        else
            echo -n ","
        fi
        echo -n "\"$item\""
    done
    echo -n "]"
}

main() {
    [[ -n "$BACKUP_SOURCES" ]] || die "BACKUP_SOURCES is required (comma-separated paths)."

    require_confirm

    local ts run_id run_dir archive excludes_file manifest
    ts="$(date -Iseconds | tr ':' '-')"
    run_id="${NODE_NAME}_${BACKUP_LABEL}_${ts}"
    run_dir="$OUTPUT_DIR/runs/$run_id"
    archive="$run_dir/archive.tar.gz"
    excludes_file="$run_dir/excludes.txt"
    manifest="$run_dir/manifest.json"

    mkdir -p "$run_dir"

    # Write excludes file
    log_info "Writing excludes: $excludes_file"
    : > "$excludes_file"
    IFS=',' read -r -a excludes <<< "$BACKUP_EXCLUDES"
    for ex in "${excludes[@]}"; do
        echo "$ex" >> "$excludes_file"
    done

    # Build tar exclude args
    local tar_excludes=()
    while IFS= read -r pat; do
        [[ -n "$pat" ]] && tar_excludes+=("--exclude=$pat")
    done < "$excludes_file"

    # Expand sources
    local expanded_sources=()
    IFS=',' read -r -a sources <<< "$BACKUP_SOURCES"
    for src in "${sources[@]}"; do
        expanded_sources+=("${src/#\~/$HOME}")
    done

    # Create archive
    log_info "Creating archive: $archive"
    tar -czf "$archive" "${tar_excludes[@]}" "${expanded_sources[@]}"

    local archive_size archive_b3
    archive_size=$(stat -c%s "$archive")
    archive_b3=$(b3_file "$archive")

    log_info "Archive size: $archive_size bytes"
    log_info "Archive BLAKE3: $archive_b3"

    # Create manifest (pure bash JSON)
    log_info "Writing manifest: $manifest"
    cat > "$manifest" <<EOF
{
  "version": 1,
  "node": "$NODE_NAME",
  "label": "$BACKUP_LABEL",
  "run_id": "$run_id",
  "created_at": "$(date -Iseconds)",
  "sources": $(json_array "$BACKUP_SOURCES"),
  "excludes": $(json_array "$BACKUP_EXCLUDES"),
  "archive": {
    "path": "archive.tar.gz",
    "bytes": $archive_size,
    "blake3": "$archive_b3"
  }
}
EOF

    # Save last run pointer
    echo "$run_dir" > "$OUTPUT_DIR/last_run_dir.txt"
    log_info "Saved last run pointer: $OUTPUT_DIR/last_run_dir.txt"

    log_info "Backup complete."
    log_info "Next: ./scripts/20_encrypt_plan.sh then 21_encrypt_apply.sh"
}

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