package cli

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/spf13/cobra"
)

const defaultConfigTemplate = `# vaultik configuration
# Documentation: https://git.eeqj.de/sneak/vaultik

# ─── REQUIRED ────────────────────────────────────────────────────────────────

# Age recipient public keys for encryption.
# Backups are encrypted to ALL listed recipients. Any one of the corresponding
# private keys can decrypt. Generate a keypair with:
#   age-keygen -o key.txt && grep 'public key' key.txt
age_recipients:
  - age1REPLACE_WITH_YOUR_PUBLIC_KEY

# Named snapshots. Each snapshot backs up one or more paths and can have its
# own exclude patterns in addition to the global excludes below.
snapshots:
  home:
    paths:
      - ~/Documents
      - ~/Pictures
    # exclude:
    #   - "*.cache"

# Storage backend (pick ONE of the three forms below).
#
# S3-compatible:
#   storage_url: "s3://mybucket/backups?endpoint=s3.example.com&region=us-east-1"
#   (also set s3.access_key_id and s3.secret_access_key below)
#
# Local filesystem:
#   storage_url: "file:///mnt/backups/vaultik"
#
# Rclone (requires rclone configured separately):
#   storage_url: "rclone://myremote/path/to/backups"
storage_url: ""

# ─── S3 CREDENTIALS (required for s3:// storage_url) ────────────────────────

# s3:
#   access_key_id: YOUR_ACCESS_KEY
#   secret_access_key: YOUR_SECRET_KEY
#   # region: us-east-1        # Default: us-east-1
#   # use_ssl: true            # Default: true
#   # part_size: 5MB           # Multipart upload part size. Default: 5MB

# ─── OPTIONAL ────────────────────────────────────────────────────────────────

# Global exclude patterns applied to ALL snapshots.
# Snapshot-specific excludes are additive.
# exclude:
#   - "*.log"
#   - "*.tmp"
#   - ".git"
#   - "node_modules"

# Average chunk size for content-defined chunking (FastCDC).
# Smaller = better deduplication but more metadata overhead.
# Accepts: 1MB, 10M, 64KB, etc.
# Default: 10MB
# chunk_size: 10MB

# Maximum blob size before splitting into a new blob.
# Accepts: 1GB, 10G, 500MB, etc.
# Default: 10GB
# blob_size_limit: 10GB

# Zstd compression level (1-19). Higher = better ratio but slower.
# Default: 3
# compression_level: 3

# Hostname used in snapshot IDs. Default: system hostname.
# hostname: myserver

# Path to the local SQLite index database.
# Default: ~/.local/share/berlin.sneak.app.vaultik/index.sqlite
# index_path: /path/to/index.sqlite
`

// NewInitCommand creates the init command that writes a default config file.
func NewInitCommand() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "init",
		Short: "Write a default config file",
		Long: `Creates a default configuration file with commented explanations
for every setting. If a config file already exists at the target path,
the command refuses to overwrite it.

The config is written to the path from --config, $VAULTIK_CONFIG, or
the platform default config directory (e.g. ~/Library/Application Support/
on macOS, ~/.config/ on Linux, /etc/vaultik/ as root).`,
		Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			path := configPathForInit()

			if _, err := os.Stat(path); err == nil {
				return fmt.Errorf("config file already exists: %s", path)
			}

			dir := filepath.Dir(path)
			if err := os.MkdirAll(dir, 0o755); err != nil {
				return fmt.Errorf("creating config directory %s: %w", dir, err)
			}

			if err := os.WriteFile(path, []byte(defaultConfigTemplate), 0o600); err != nil {
				return fmt.Errorf("writing config file: %w", err)
			}

			fmt.Printf("Config written to %s\n", path)
			fmt.Println("Edit it to set your age_recipients, snapshots, and storage_url.")
			return nil
		},
	}

	return cmd
}

// configPathForInit returns the config path to write, checking --config flag,
// VAULTIK_CONFIG env, and the platform default.
func configPathForInit() string {
	if rootFlags.ConfigPath != "" {
		return rootFlags.ConfigPath
	}
	if envPath := os.Getenv("VAULTIK_CONFIG"); envPath != "" {
		return envPath
	}
	return DefaultConfigPath()
}