package config

import (
	"fmt"
	"os"
	"time"

	"github.com/spf13/cobra"
)

// Config holds all runtime configuration for ha-sync.
type Config struct {
	Src            string
	Dest           string
	Pair           string
	Direction      string
	DBDSN          string
	LockTTL        int
	LogDir         string
	LogRetainDays  int
	MtimeThreshold time.Duration
	DeleteMissing  bool
	Workers        int
	DryRun         bool
	Verbose        bool
	KubeNamespace  string
	Excludes       []string // glob patterns passed via --exclude flags
	SrcHost        string
	DestHost       string
}

// NewRootCmd returns a configured cobra root command with all flags bound to a
// Config. Call FromFlags(cmd) after Execute() to obtain a validated *Config.
func NewRootCmd() *cobra.Command {
	cfg := &Config{}

	cmd := &cobra.Command{
		Use:   "ha-sync",
		Short: "Bidirectional HA file-sync with leader-election and audit logging",
		Long: `ha-sync copies files from a source directory to a destination directory,
ensuring only one instance runs per sync pair at a time via a Kubernetes Lease.

Each run is recorded in MySQL with per-file operation details. Use --dry-run to
preview what would change without writing any files.

Examples:
  # Sync /data/media from Dell to HP (production)
  ha-sync --src=/data/media --dest=/mnt/hp/media --pair=media --direction=dell-to-hp

  # Dry-run first to preview changes
  ha-sync --src=/data/media --dest=/mnt/hp/media --pair=media --direction=dell-to-hp --dry-run

  # Exclude temporary and lock files
  ha-sync --src=/data/infra --dest=/mnt/hp/infra --pair=infra --direction=dell-to-hp \
    --exclude='*.sock' --exclude='*.lock' --exclude='*.pid'`,
	}

	f := cmd.Flags()
	f.StringVar(&cfg.Src, "src", "", "Source directory path (required)")
	f.StringVar(&cfg.Dest, "dest", "", "Destination directory path (required)")
	f.StringVar(&cfg.Pair, "pair", "", "Unique name for this sync pair; used as the Kubernetes Lease name ha-sync-<pair> (required)")
	f.StringVar(&cfg.Direction, "direction", "fwd", "Label stored in the audit log identifying sync direction (e.g. dell-to-hp, hp-to-dell)")
	f.StringVar(&cfg.DBDSN, "db-dsn", "", "MySQL DSN for audit logging. Defaults to env HA_SYNC_DB_DSN (format: user:pass@tcp(host:port)/db?parseTime=true)")
	f.IntVar(&cfg.LockTTL, "lock-ttl", 3600, "Kubernetes Lease TTL in seconds; a crashed pod releases the lock after this duration")
	f.StringVar(&cfg.LogDir, "log-dir", "/var/log/ha-sync", "Directory for file-based operation logs")
	f.IntVar(&cfg.LogRetainDays, "log-retain-days", 10, "Number of days to retain log files before rotation")
	f.DurationVar(&cfg.MtimeThreshold, "mtime-threshold", 2*time.Second, "Minimum mtime difference required to treat a same-size file as changed (avoids NFS clock skew false positives)")
	f.BoolVar(&cfg.DeleteMissing, "delete-missing", false, "Delete files in dest that no longer exist in src (use with caution)")
	f.IntVar(&cfg.Workers, "workers", 4, "Number of concurrent file-copy workers")
	f.BoolVar(&cfg.DryRun, "dry-run", false, "Preview what would be synced without writing any files; results are recorded in the DB with dry_run=true")
	f.BoolVar(&cfg.Verbose, "verbose", false, "Log every file operation (create/update/skip); default logs only errors and summary")
	f.StringVar(&cfg.KubeNamespace, "kube-namespace", "infrastructure", "Kubernetes namespace where the Lease object is managed")
	f.StringArrayVar(&cfg.Excludes, "exclude", nil, "Glob pattern to skip (may be repeated). Matched against the file's base name and its path relative to src. Supports * and ? wildcards. Example: --exclude='*.sock' --exclude='tmp/*'")
	f.StringVar(&cfg.SrcHost, "src-host", "dell", "Label for the source host (stored in audit log, e.g. dell, hp)")
	f.StringVar(&cfg.DestHost, "dest-host", "hp", "Label for the destination host (stored in audit log, e.g. dell, hp)")

	return cmd
}

// FromFlags reads flag values from cmd and returns a validated Config.
// It returns an error if any required field is missing.
func FromFlags(cmd *cobra.Command) (*Config, error) {
	f := cmd.Flags()

	src, _ := f.GetString("src")
	dest, _ := f.GetString("dest")
	pair, _ := f.GetString("pair")
	direction, _ := f.GetString("direction")
	dbDSN, _ := f.GetString("db-dsn")
	lockTTL, _ := f.GetInt("lock-ttl")
	logDir, _ := f.GetString("log-dir")
	logRetainDays, _ := f.GetInt("log-retain-days")
	mtimeThreshold, _ := f.GetDuration("mtime-threshold")
	deleteMissing, _ := f.GetBool("delete-missing")
	workers, _ := f.GetInt("workers")
	dryRun, _ := f.GetBool("dry-run")
	verbose, _ := f.GetBool("verbose")
	kubeNamespace, _ := f.GetString("kube-namespace")
	excludes, _ := f.GetStringArray("exclude")
	srcHost, _ := f.GetString("src-host")
	destHost, _ := f.GetString("dest-host")

	if src == "" {
		return nil, fmt.Errorf("--src is required")
	}
	if dest == "" {
		return nil, fmt.Errorf("--dest is required")
	}
	if pair == "" {
		return nil, fmt.Errorf("--pair is required")
	}

	// Fall back to env if the flag was left at its default empty value.
	if dbDSN == "" {
		dbDSN = os.Getenv("HA_SYNC_DB_DSN")
	}
	if dbDSN == "" {
		return nil, fmt.Errorf("--db-dsn or env HA_SYNC_DB_DSN is required")
	}

	return &Config{
		Src:            src,
		Dest:           dest,
		Pair:           pair,
		Direction:      direction,
		DBDSN:          dbDSN,
		LockTTL:        lockTTL,
		LogDir:         logDir,
		LogRetainDays:  logRetainDays,
		MtimeThreshold: mtimeThreshold,
		DeleteMissing:  deleteMissing,
		Workers:        workers,
		DryRun:         dryRun,
		Verbose:        verbose,
		KubeNamespace:  kubeNamespace,
		Excludes:       excludes,
		SrcHost:        srcHost,
		DestHost:       destHost,
	}, nil
}