{ config, lib, pkgs, ... }:

with lib;

let
  cfg = config.services.lnbits-backup;

in {
  options.services.lnbits-backup = {
    enable = mkEnableOption "LNbits Borg Backup Service";

    dataPath = mkOption {
      type = types.path;
      default = "/var/lib/lnbits/data";
      description = "Path to LNbits data directory";
    };

    repository = mkOption {
      type = types.str;
      example = "ssh://borg@192.168.1.100//mnt/my_ssd/borg-backups/lnbits";
      description = "Borg repository location (SSH URL or user@host:/path format)";
    };

    schedule = mkOption {
      type = types.str;
      default = "hourly";
      description = "Backup schedule (hourly, daily, or systemd timer format)";
    };

    compression = mkOption {
      type = types.str;
      default = "auto,lz4";
      description = "Compression: auto,lz4 (Pi), auto,zstd (RockPro64). 'auto' skips already-compressed files.";
    };

    passphraseFile = mkOption {
      type = types.path;
      default = "/root/secrets/borg-passphrase";
      description = "Path to Borg passphrase file";
    };

    sshKeyFile = mkOption {
      type = types.path;
      default = "/root/.ssh/borg_backup_key";
      description = "SSH private key for repository access";
    };

    retention = {
      hourly = mkOption { type = types.int; default = 24; };
      daily = mkOption { type = types.int; default = 7; };
      weekly = mkOption { type = types.int; default = 4; };
      monthly = mkOption { type = types.int; default = 6; };
    };

    alertEmail = mkOption {
      type = types.nullOr types.str;
      default = null;
      description = "Email for alerts (optional)";
    };
  };

  config = mkIf cfg.enable {
    services.borgbackup.jobs.lnbits = {
      paths = [
        cfg.dataPath
        "/tmp/lnbits-snapshot.sqlite3"
      ];

      exclude = [ "*.log" "*.pyc" "__pycache__" "*.tmp" ];
      repo = cfg.repository;

      encryption = {
        mode = "repokey-blake2";
        passCommand = "cat ${cfg.passphraseFile}";
      };

      compression = cfg.compression;
      startAt = cfg.schedule;
      persistentTimer = true;  # Run missed backups after reboots

      prune.keep = {
        inherit (cfg.retention) hourly daily weekly monthly;
      };

      preHook = ''
        echo "=== LNbits Backup Starting: $(date) ==="

        if [ -f "${cfg.dataPath}/database.sqlite3" ]; then
          echo "Creating SQLite snapshot..."
          ${pkgs.sqlite}/bin/sqlite3 "${cfg.dataPath}/database.sqlite3" \
            ".backup '/tmp/lnbits-snapshot.sqlite3'"

          SIZE=$(stat -c%s "/tmp/lnbits-snapshot.sqlite3")
          echo "Snapshot created: $SIZE bytes"

          if [ "$SIZE" -lt 1000 ]; then
            echo "ERROR: Snapshot too small!"
            rm -f /tmp/lnbits-snapshot.sqlite3
            exit 1
          fi
        else
          echo "ERROR: Database not found!"
          exit 1
        fi
      '';

      postHook = ''
        rm -f /tmp/lnbits-snapshot.sqlite3

        # Weekly integrity check (Sundays)
        if [ $(date +%u) -eq 7 ]; then
          echo "Running weekly integrity check..."
          ${pkgs.borgbackup}/bin/borg check --repository-only ${cfg.repository}
        fi

        echo "=== Backup Complete: $(date) ==="
      '';

      environment = {
        BORG_RSH = "ssh -i ${cfg.sshKeyFile} -o StrictHostKeyChecking=accept-new";
      };
    };

    # Install required packages and helper commands
    environment.systemPackages = with pkgs; [
      borgbackup
      sqlite

      (writeShellScriptBin "lnbits-borg-list" ''
        export BORG_PASSPHRASE=$(cat ${cfg.passphraseFile})
        export BORG_RSH="ssh -i ${cfg.sshKeyFile}"
        ${borgbackup}/bin/borg list ${cfg.repository} "$@"
      '')

      (writeShellScriptBin "lnbits-borg-info" ''
        export BORG_PASSPHRASE=$(cat ${cfg.passphraseFile})
        export BORG_RSH="ssh -i ${cfg.sshKeyFile}"
        ${borgbackup}/bin/borg info ${cfg.repository} "$@"
      '')

      (writeShellScriptBin "lnbits-borg-restore" ''
        if [ $# -lt 1 ]; then
          echo "Usage: lnbits-borg-restore <archive-name> [destination]"
          echo ""
          echo "Available archives:"
          lnbits-borg-list
          exit 1
        fi

        ARCHIVE="$1"
        DEST="''${2:-/tmp/lnbits-restore}"

        export BORG_PASSPHRASE=$(cat ${cfg.passphraseFile})
        export BORG_RSH="ssh -i ${cfg.sshKeyFile}"

        mkdir -p "$DEST"
        cd "$DEST"
        echo "Restoring to: $DEST"
        ${borgbackup}/bin/borg extract ${cfg.repository}::$ARCHIVE
        echo "Done! Restored files in: $DEST"
      '')

      (writeShellScriptBin "lnbits-borg-mount" ''
        MOUNT="''${1:-/mnt/borg-browse}"

        export BORG_PASSPHRASE=$(cat ${cfg.passphraseFile})
        export BORG_RSH="ssh -i ${cfg.sshKeyFile}"

        mkdir -p "$MOUNT"
        ${borgbackup}/bin/borg mount ${cfg.repository} "$MOUNT"
        echo "Mounted at: $MOUNT"
        echo "Unmount: borg umount $MOUNT"
      '')
    ];
  };
}