// Package bridge provides configuration management for platform adapters.
// Configs are stored as JSON on disk and loaded only when created via the admin panel.
// Supports hot-reload: the router watches the config file and reloads adapters on change.
package bridge

import (
	"encoding/json"
	"fmt"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/logger"
	"os"
	"path/filepath"
	"sync"
	"time"
)

// AdapterConfig holds configuration for a single platform adapter.
type AdapterConfig struct {
	Name      string            `json:"name"`
	Type      string            `json:"type"` // "qq-obv11" | "telegram" | "discord" | "webhook"
	Enabled   bool              `json:"enabled"`
	Settings  map[string]string `json:"settings"`
	CreatedAt string            `json:"created_at"`
	UpdatedAt string            `json:"updated_at"`
}

// BridgeConfig is the top-level configuration file structure.
type BridgeConfig struct {
	Version   string          `json:"version"`
	UpdatedAt string          `json:"updated_at"`
	Adapters  []AdapterConfig `json:"adapters"`
}

// ConfigStore manages bridge configurations with file persistence.
type ConfigStore struct {
	mu       sync.RWMutex
	path     string
	config   *BridgeConfig
	onChange func(*BridgeConfig) // Called when config is loaded or reloaded
	stopCh   chan struct{}
}

// NewConfigStore creates a bridge config store. Path is the config file location.
// If the file doesn't exist, no config is created — it will be created on first save via admin panel.
func NewConfigStore(path string, onChange func(*BridgeConfig)) *ConfigStore {
	s := &ConfigStore{
		path:     path,
		config:   &BridgeConfig{Version: "1.0", Adapters: []AdapterConfig{}},
		onChange: onChange,
		stopCh:   make(chan struct{}),
	}

	// Try to load existing file
	if _, err := os.Stat(path); err == nil {
		s.load()
		if s.onChange != nil {
			s.onChange(s.config)
		}
	}

	return s
}

// StartWatching begins polling the config file for changes (hot-reload).
func (s *ConfigStore) StartWatching(interval time.Duration) {
	var lastMod time.Time
	if info, err := os.Stat(s.path); err == nil {
		lastMod = info.ModTime()
	}

	go func() {
		ticker := time.NewTicker(interval)
		defer ticker.Stop()
		for {
			select {
			case <-s.stopCh:
				return
			case <-ticker.C:
				info, err := os.Stat(s.path)
				if err != nil {
					continue
				}
				if info.ModTime().After(lastMod) {
					lastMod = info.ModTime()
					s.mu.Lock()
					if s.load() {
						logger.Infof("[bridge] config hot-reloaded (%d adapters)", len(s.config.Adapters))
						if s.onChange != nil {
							s.onChange(s.config)
						}
					}
					s.mu.Unlock()
				}
			}
		}
	}()
}

// Stop stops the file watcher.
func (s *ConfigStore) Stop() { close(s.stopCh) }

// GetAdapters returns all configured adapters.
func (s *ConfigStore) GetAdapters() []AdapterConfig {
	s.mu.RLock()
	defer s.mu.RUnlock()
	result := make([]AdapterConfig, len(s.config.Adapters))
	copy(result, s.config.Adapters)
	return result
}

// GetAdapter returns a single adapter by name.
func (s *ConfigStore) GetAdapter(name string) (*AdapterConfig, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()
	for _, a := range s.config.Adapters {
		if a.Name == name {
			ac := a
			return &ac, nil
		}
	}
	return nil, fmt.Errorf("adapter %s not found", name)
}

// SaveAdapter creates or updates an adapter config.
func (s *ConfigStore) SaveAdapter(cfg AdapterConfig) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	now := time.Now().Format(time.RFC3339)
	cfg.UpdatedAt = now
	if cfg.CreatedAt == "" {
		cfg.CreatedAt = now
	}

	found := false
	for i, a := range s.config.Adapters {
		if a.Name == cfg.Name {
			// Preserve creation time
			if a.CreatedAt != "" { cfg.CreatedAt = a.CreatedAt }
			s.config.Adapters[i] = cfg
			found = true
			break
		}
	}
	if !found {
		s.config.Adapters = append(s.config.Adapters, cfg)
	}

	s.config.UpdatedAt = now
	return s.persist()
}

// DeleteAdapter removes an adapter config.
func (s *ConfigStore) DeleteAdapter(name string) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	filtered := make([]AdapterConfig, 0)
	for _, a := range s.config.Adapters {
		if a.Name != name {
			filtered = append(filtered, a)
		}
	}
	s.config.Adapters = filtered
	s.config.UpdatedAt = time.Now().Format(time.RFC3339)
	return s.persist()
}

// Count returns the number of enabled adapters.
func (s *ConfigStore) Count() int {
	s.mu.RLock()
	defer s.mu.RUnlock()
	n := 0
	for _, a := range s.config.Adapters {
		if a.Enabled { n++ }
	}
	return n
}

// load reads the config file from disk. Returns true if loaded successfully.
func (s *ConfigStore) load() bool {
	data, err := os.ReadFile(s.path)
	if err != nil {
		return false
	}
	var cfg BridgeConfig
	if err := json.Unmarshal(data, &cfg); err != nil {
		logger.Infof("[bridge] config parse error: %v", err)
		return false
	}
	if cfg.Adapters == nil {
		cfg.Adapters = []AdapterConfig{}
	}
	s.config = &cfg
	return true
}

// persist writes the current config to disk.
func (s *ConfigStore) persist() error {
	data, err := json.MarshalIndent(s.config, "", "  ")
	if err != nil {
		return fmt.Errorf("marshal config: %w", err)
	}
	// Ensure parent dir exists
	os.MkdirAll(filepath.Dir(s.path), 0o755)
	if err := os.WriteFile(s.path, data, 0o644); err != nil {
		return fmt.Errorf("write config: %w", err)
	}
	return nil
}