package protocoldb

import (
	"fmt"
	"io/fs"
	"log"
	"os"
	"os/user"
	"path"
	"path/filepath"

	"github.com/go-git/go-git/v5"

	"gitea.mmo.to/ppForge/ppforge/protocol"
	"gitea.mmo.to/ppForge/ppforge/protocolctl"
)

// PPFDatabases is a list of all databases, with the most simple interface
type PPFDatabases struct {
	Databases []ProtocolDatabaseProvider
}

// ProtocolDatabaseProvider is a simple protocol database interface, which only provides open/close and retrieving the contents
type ProtocolDatabaseProvider interface {
	// Open opens a new database
	Open(path string) error
	// Close closes a database (only internal flag set)
	Close() error
	// Protocols returns the content of the database as map, an error if the first read of the database failed
	Protocols() ([]DatabaseEntry, error)
}

// ProtocolDatabaseManager is a complex protocol database interface, which allows adding, updating and refreshing of the content
type ProtocolDatabaseManager interface {
	Add(prot *protocol.ProtocolStructure) error
	Update(prot *protocol.ProtocolStructure) error
	// no remove.
	UpdateDatabase() error // scans for new protocols
}

// DatabaseEntry is a single entry in the file database, additionally to the meta data the path is required
type DatabaseEntry struct {
	Path     string
	Protocol protocol.DOPMeta
}

// Init initializes the databases, opens the default one and checks for others if available
func Init() *PPFDatabases {
	// initialize main list
	databases := PPFDatabases{[]ProtocolDatabaseProvider{}}
	// initialize default db
	user, err := user.Current()
	if err != nil {
		log.Printf("Current user not obtainable: %s", err)
		log.Fatal("Impossible to open default database")
	}
	pathlist := []string{user.HomeDir, ".config", "ppforge"}
	fdb := FileDatabase{path.Join(pathlist...), map[string]DatabaseEntry{}, false}
	fdb.Open(path.Join(pathlist...))
	fdb.UpdateDatabase()
	databases.Databases = append(databases.Databases, fdb)
	log.Printf("Amount of databases available %d", len(databases.Databases))
	return &databases
}

// Get Retrieves the full set of databases
func (ppfdb *PPFDatabases) Get() []ProtocolDatabaseProvider {
	return ppfdb.Databases
}

// Get a full protocol from a database entry
func (de *DatabaseEntry) Get() (*protocol.ProtocolStructure, error) {
	return protocolctl.LoadNew(de.Path)
}

// FileDatabase implements ProtocolDatabaseProvider and ProtocolDatabaseManager
type FileDatabase struct {
	Path      string
	protocols map[string]DatabaseEntry
	closed    bool
}

// FileDatabaseFromGitRemote implements retrieving the latest stuff from an external git remote additionally to the FileDatabase functionality
// TODO
type FileDatabaseFromGitRemote struct {
	FileDatabase
	RemoteGitRepository string
	gitRepo             git.Repository
}

// Open the database
func (fd FileDatabase) Open(path string) error {
	fileinfo, err := os.Stat(path)
	if err == os.ErrNotExist {
		return err
	}
	if !fileinfo.IsDir() {
		return fmt.Errorf("Path %s is not a directory", path)
	}
	fd.Path = path
	fd.closed = false
	return nil
}

// Close the database and free the data
func (fd FileDatabase) Close() error {
	for k := range fd.protocols {
		delete(fd.protocols, k)
	}
	fd.closed = true
	return nil
}

// Protocols returns the map of protocols or an error if the first read failed
func (fd FileDatabase) Protocols() ([]DatabaseEntry, error) {
	entries := []DatabaseEntry{}
	if !fd.closed && len(fd.protocols) == 0 {
		fd.protocols = map[string]DatabaseEntry{}
		// recurse recursively through the path
		err := filepath.Walk(fd.Path, func(path string, info fs.FileInfo, err error) error {
			if !info.IsDir() {
				prot, err := protocolctl.LoadNew(path)
				if err == nil {
					// add to map
					entry := DatabaseEntry{path, prot.Metadata}

					fd.protocols[prot.Metadata.Name] = entry
					entries = append(entries, entry)
				}
			}
			return nil
		})
		if err != nil {
			return nil, err
		}
	}
	if entries == nil || len(entries) == 0 {
		entries = make([]DatabaseEntry, len(fd.protocols))
		for _, v := range fd.protocols {
			entries = append(entries, v)
		}
	}
	return entries, nil
}

// Add puts a new protocol into the path of the file database
func (fd *FileDatabase) Add(prot *protocol.ProtocolStructure) error {
	p := path.Join(fd.Path, prot.Metadata.Name, ".protocoljson")
	err := protocolctl.Save(prot, p)
	if err == nil {
		fd.protocols[prot.Metadata.Name] = DatabaseEntry{p, prot.Metadata}
	}
	return err
}

// Update updates an existing entry through saving the contents of the protocol to the file, or just adding it anew
func (fd *FileDatabase) Update(prot *protocol.ProtocolStructure) error {
	if v, ok := fd.protocols[prot.Metadata.Name]; ok {
		v.Protocol = prot.Metadata
		return protocolctl.Save(prot, v.Path)
	}
	return fd.Add(prot)
}

// UpdateDatabase just rereads all files
func (fd *FileDatabase) UpdateDatabase() error {
	// recurse recursively through the path
	err := filepath.Walk(fd.Path, func(path string, info fs.FileInfo, err error) error {
		if !info.IsDir() {
			prot, err := protocolctl.LoadNew(path)
			if err == nil {
				// add to map
				fd.protocols[prot.Metadata.Name] = DatabaseEntry{path, prot.Metadata}
			}
		}
		return nil
	})
	return err
}