package database

import (
	// Standard
	"encoding/json"
	"errors"
	"os"
	"sync"
)

// Database
type database struct {
	path  string
	mutex sync.Mutex
	data  databaseData
}

// Database Data
type databaseData struct {
	IPv4Address string                  `json:"ipv4_address"`
	IPv6Address string                  `json:"ipv6_address"`
	DDNSEntries []DatabaseDataDDNSEntry `json:"ddns_entries"`
}

// Database Data DDNS Entry
type DatabaseDataDDNSEntry struct {
	Record       string      `json:"record"`
	Updated      bool        `json:"updated"`
	Provider     string      `json:"provider"`
	ProviderData interface{} `json:"provider_data"`
}

// Database Data DDNS Entry Provider Data Cloudflare
type DatabaseDataDDNSEntryProviderDataCloudflare struct {
	APIToken string `json:"api_token"`
	ZoneID   string `json:"zone_id"`
}

// Save
func (db *database) save() error {
	// Marshal Data
	jsonData, err := json.MarshalIndent(db.data, "", "    ")
	// Handle Error
	if err != nil {
		return err
	}
	// Save Data
	return os.WriteFile(db.path, jsonData, 0644)
}

// Load
func (db *database) load() error {
	// Load Data
	jsonData, err := os.ReadFile(db.path)
	// Handle Error
	if err != nil {
		return err
	}
	// Unmarshal Data
	err = json.Unmarshal(jsonData, &db.data)
	// Handle Error
	if err != nil {
		return err
	}
	// Unmarshal DDNS Entries
	for entryNumber, entry := range db.data.DDNSEntries {
		switch entry.Provider {
		// Cloudflare
		case "Cloudflare":
			// Entry Data
			var entryData DatabaseDataDDNSEntryProviderDataCloudflare
			// Marshal Entry Data
			data, err := json.Marshal(entry.ProviderData)
			// Handle Error
			if err != nil {
				return err
			}
			// Unmarshal Entry Data
			err = json.Unmarshal(data, &entryData)
			// Handle Error
			if err != nil {
				return err
			}
			// Set Provider Data
			db.data.DDNSEntries[entryNumber].ProviderData = entryData
		// Default
		default:
			return errors.New("unknown ddns entry provider")
		}
	}
	// Success
	return nil
}

// Create
func Create(path string) *database {
	// Database
	db := database{
		path:  path,
		mutex: sync.Mutex{},
		data:  databaseData{},
	}
	// Check File
	_, err := os.Stat(db.path)
	// File Does Not Exist
	if os.IsNotExist(err) {
		// Create File
		file, err := os.Create(db.path)
		// Handle Error
		if err != nil {
			panic(err)
		}
		// Close File
		file.Close()
		// Save Database
		err = db.save()
		// Handle Error
		if err != nil {
			panic(err)
		}
		// Success
		return &db
	} else if err != nil {
		// Handle Error
		panic(err)
	}
	// Load
	err = db.load()
	// Handle Error
	if err != nil {
		panic(err)
	}
	// Success
	return &db
}

// Set IPv4 Address
func (db *database) SetIPv4Address(ipv4Address string) error {
	// Lock
	db.mutex.Lock()
	defer db.mutex.Unlock()
	// Set IPv4 Address
	db.data.IPv4Address = ipv4Address
	// Reset Updated
	for entryNumber := range db.data.DDNSEntries {
		db.data.DDNSEntries[entryNumber].Updated = false
	}
	// Save
	return db.save()
}

// Set IPv6 Address
func (db *database) SetIPv6Address(ipv6Address string) error {
	// Lock
	db.mutex.Lock()
	defer db.mutex.Unlock()
	// Set IPv6 Address
	db.data.IPv6Address = ipv6Address
	// Reset Updated
	for entryNumber := range db.data.DDNSEntries {
		db.data.DDNSEntries[entryNumber].Updated = false
	}
	// Save
	return db.save()
}

// Get IPv4 Address
func (db *database) GetIPv4Address() string {
	return db.data.IPv4Address
}

// Get IPv6 Address
func (db *database) GetIPv6Address() string {
	return db.data.IPv6Address
}

// Add Entry
func (db *database) AddEntry(entry DatabaseDataDDNSEntry) error {
	// Lock
	db.mutex.Lock()
	defer db.mutex.Unlock()
	// Check Entry
	for _, existingEntry := range db.data.DDNSEntries {
		if entry.Record == existingEntry.Record {
			return errors.New("entry exists")
		}
	}
	// Add Entry
	db.data.DDNSEntries = append(db.data.DDNSEntries, entry)
	// Save
	return db.save()
}

// Update Entry
func (db *database) UpdateEntry(record string) error {
	// Lock
	db.mutex.Lock()
	defer db.mutex.Unlock()
	// Update Entry
	for entryNumber, entry := range db.data.DDNSEntries {
		if entry.Record == record {
			db.data.DDNSEntries[entryNumber].Updated = true
			break
		}
	}
	// Save
	return db.save()
}

// Get Entries
func (db *database) GetEntries() []DatabaseDataDDNSEntry {
	return db.data.DDNSEntries
}

// Delete Entry
func (db *database) DeleteEntry(record string) error {
	// Lock
	db.mutex.Lock()
	defer db.mutex.Unlock()
	// Delete Entry
	for entryNumber, entry := range db.data.DDNSEntries {
		if entry.Record == record {
			db.data.DDNSEntries = append(db.data.DDNSEntries[:entryNumber], db.data.DDNSEntries[entryNumber+1:]...)
		}
	}
	// Save
	return db.save()
}