package webdavupload

import (
    "os"
    "sync"
    "time"
    "github.com/studio-b12/gowebdav"
    "gitea.armuli.eu/museum-digital/museum-digital-webdav-uploader/src/configloader"
)

// Takes a path on the webdav remote and reads folder contents from it.
func listWebDavFolderContents(config configloader.MDWebDavUploaderConfig, path string) ([]os.FileInfo, error) {

    c := gowebdav.NewClient(getWebDavHost(config), config.Username, config.WebDavAuthToken)
    c.Connect()

    files, err := c.ReadDir(path)
    return files, err

}

// Returns a list of the files on the top level of the remote.
func ListTopLevelContents(config configloader.MDWebDavUploaderConfig) ([]os.FileInfo, error) {
    return listWebDavFolderContents(config, ".")
}

// Returns a list of the files in the current metadata dir of the remote.
func ListMetadataDir(config configloader.MDWebDavUploaderConfig) ([]os.FileInfo, error) {
    return listWebDavFolderContents(config, "./IMPORT_XML")
}

// Returns a list of the files in the current media dir of the remote.
func ListMediaDir(config configloader.MDWebDavUploaderConfig) ([]os.FileInfo, error) {
    return listWebDavFolderContents(config, "./IMPORT_IMG")
}

func checkImportConfigExists(c *gowebdav.Client) bool {

    _, err := c.Stat("./import_config.txt")
    if gowebdav.IsErrNotFound(err) == true {
        return false
    }
    return true

}

// Checks if a remote directory is free for updating:
// This means it can be read, and it does not contain files more recent than
// 10 minutes.
func checkRemoteDirIsFree(c *gowebdav.Client, path string) bool {

    now := time.Now()

    // Check metadata dir
    files, err := c.ReadDir(path)

    if err != nil {
        print("Failed to load remote contents")
        return false
    }

    for _, f := range(files) {
        if diff := now.Sub(f.ModTime()); diff < 10 * time.Minute {
            print("File " + f.Name() + " has been recently renamed")
            return false
        }
    }

    return true

}

// Checks if either the metadata or the image folder contains files that have
// been changed in the last 10 minutes.
// In this case, it can be assumed that there is a concurrent upload taking place.
func checkRemoteImportFilesAreTooRecent(c *gowebdav.Client) bool {

    var wg sync.WaitGroup
    var metadataDirFree bool
    var mediaDirFree bool

    wg.Add(2)
    go func() {
        defer wg.Done()
        metadataDirFree = checkRemoteDirIsFree(c, "./IMPORT_XML")
    }()
    go func() {
        defer wg.Done()
        mediaDirFree = checkRemoteDirIsFree(c, "./IMPORT_IMG")
    }()
    wg.Wait()

    if metadataDirFree == true && mediaDirFree == true {
        return false
    }
    return true

}

// Checks the remote for the existence of an import_config.txt.
func CheckRemoteIsFree(c *gowebdav.Client) bool {

    if checkImportConfigExists(c) == true {
        return false
    }

    // Check if the remote media and metadata directories currently
    // contain very recent files indicating a concurrent upload.
    if checkRemoteImportFilesAreTooRecent(c) == true {
        return false
    }

    return true

}