// Package storage handles cross-platform persistence of configuration and
// subscription data, using YAML files under a per-user config directory.
package storage

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

	"gopkg.in/yaml.v3"

	"gitea.epss.net.cn/klesh/ss/internal/model"
	"gitea.epss.net.cn/klesh/ss/internal/yamlutil"
)

// Manager manages cross-platform data storage for subscriptions and configuration.
type Manager struct {
	ConfigDir         string
	ConfigFile        string
	SubscriptionsFile string
}

// New creates a Manager, resolving the config directory (SF_CONFIG_DIR env
// var, falling back to ~/basicfiles/cli/ss) and ensuring it exists.
func New() (*Manager, error) {
	configDir, err := getConfigDir()
	if err != nil {
		return nil, err
	}

	m := &Manager{
		ConfigDir:         configDir,
		ConfigFile:        filepath.Join(configDir, "config.yaml"),
		SubscriptionsFile: filepath.Join(configDir, "subscriptions.yaml"),
	}

	if err := os.MkdirAll(m.ConfigDir, 0o755); err != nil {
		return nil, fmt.Errorf("failed to create config directory: %w", err)
	}

	return m, nil
}

func getConfigDir() (string, error) {
	if dir := os.Getenv("SF_CONFIG_DIR"); dir != "" {
		return dir, nil
	}

	home, err := os.UserHomeDir()
	if err != nil {
		return "", fmt.Errorf("failed to determine home directory: %w", err)
	}
	return filepath.Join(home, "basicfiles", "cli", "ss"), nil
}

// LoadSubscriptions loads subscriptions from the YAML file, returning an
// empty collection if the file doesn't exist or fails to parse.
func (m *Manager) LoadSubscriptions() *model.SubscriptionsData {
	data := model.NewSubscriptionsData()

	raw, err := os.ReadFile(m.SubscriptionsFile)
	if err != nil {
		return data
	}

	if err := yamlutil.Unmarshal(raw, data); err != nil {
		fmt.Printf("Warning: Failed to load subscriptions: %v\n", err)
		return model.NewSubscriptionsData()
	}
	if data.Subscriptions == nil {
		data.Subscriptions = make(map[string]*model.Subscription)
	}
	return data
}

// SaveSubscriptions writes subscriptions to the YAML file.
func (m *Manager) SaveSubscriptions(data *model.SubscriptionsData) bool {
	out, err := yaml.Marshal(data)
	if err != nil {
		fmt.Printf("Error: Failed to save subscriptions: %v\n", err)
		return false
	}
	if err := os.WriteFile(m.SubscriptionsFile, out, 0o644); err != nil {
		fmt.Printf("Error: Failed to save subscriptions: %v\n", err)
		return false
	}
	return true
}

// LoadConfig loads the raw application config as a generic map, matching the
// Python version's dict-based (non-strict) handling of config.yaml.
func (m *Manager) LoadConfig() map[string]interface{} {
	raw, err := os.ReadFile(m.ConfigFile)
	if err != nil {
		return map[string]interface{}{}
	}

	var data map[string]interface{}
	if err := yamlutil.Unmarshal(raw, &data); err != nil {
		fmt.Printf("Warning: Failed to load config: %v\n", err)
		return map[string]interface{}{}
	}
	if data == nil {
		return map[string]interface{}{}
	}
	return data
}

// SaveConfig writes the application config to the YAML file.
func (m *Manager) SaveConfig(config map[string]interface{}) bool {
	out, err := yaml.Marshal(config)
	if err != nil {
		fmt.Printf("Error: Failed to save config: %v\n", err)
		return false
	}
	if err := os.WriteFile(m.ConfigFile, out, 0o644); err != nil {
		fmt.Printf("Error: Failed to save config: %v\n", err)
		return false
	}
	return true
}

// Info describes the storage location, mirroring get_storage_info().
type Info struct {
	ConfigDir         string
	ConfigFile        string
	SubscriptionsFile string
	Platform          string
	Exists            bool
}

// GetStorageInfo returns information about the storage location.
func (m *Manager) GetStorageInfo() Info {
	_, err := os.Stat(m.ConfigDir)
	return Info{
		ConfigDir:         m.ConfigDir,
		ConfigFile:        m.ConfigFile,
		SubscriptionsFile: m.SubscriptionsFile,
		Platform:          platformName(),
		Exists:            err == nil,
	}
}

func platformName() string {
	switch runtime.GOOS {
	case "darwin":
		return "Darwin"
	case "linux":
		return "Linux"
	case "windows":
		return "Windows"
	default:
		return runtime.GOOS
	}
}