package protocoldb

import (
	"fmt"
	"io/fs"
	"os"
	"path"
	"path/filepath"
	"strings"

	"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() (map[string]protocol.DOPMeta, 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
	AddFile(path string) error
	Update(prot *protocol.ProtocolStructure) error
	UpdateFile(path string) 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
}

// 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
}

// 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() (map[string]DatabaseEntry, error) {
	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
					fd.protocols[prot.Metadata.Name] = DatabaseEntry{path, prot.Metadata}
				}
			}
			return nil
		})
		if err != nil {
			return nil, err
		}
	}
	return fd.protocols, 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
}

// AddFile copies a external protocoljson file into the database directory and updates the internal data
func (fd *FileDatabase) AddFile(p string) error {
	prot, err := protocolctl.LoadNew(p)
	if err == nil {
		if !strings.HasPrefix(p, fd.Path) {
			// add it to the database if not existing there
			fd.Add(prot)
		}
		p = path.Join(fd.Path, prot.Metadata.Name, ".protocoljson")
		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)
}

// UpdateFile simply adds a file if it is outside the database, or updates the internal storage with the contents of the file
func (fd *FileDatabase) UpdateFile(p string) error {
	if !strings.HasPrefix(p, fd.Path) {
		return fd.AddFile(p)
	}
	prot, err := protocolctl.LoadNew(p)
	if err == nil {
		fd.protocols[prot.Metadata.Name] = DatabaseEntry{p, prot.Metadata}
	}
	return err
}

// 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
}