@startuml
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note as Lines
    Green lines are happy paths. 
    Red lines are error paths.
    Blue lines are stop paths.

    In general any action for any state can produce error.
    And the sync process can be stopped during any action.
end note


[*] -> validateServer

validateServer : ValidateServerAction
validateServer -[#green,bold]-> computeSyncRanges
validateServer -[#red]-> failed : Error occured.
validateServer -[#blue]-> stopped : Sync was stopped.

computeSyncRanges : ComputeSyncRangesAction
computeSyncRanges -[#green,bold]-> checksBeforeSync
computeSyncRanges -[#red]-> failed : Error occured.
computeSyncRanges -[#blue]-> stopped : Sync was stopped.

checksBeforeSync : ChecksBeforeSyncAction
checksBeforeSync -[#green,bold]-> fetchUTXO
checksBeforeSync -[#red]-> failed : Error occured.
checksBeforeSync -[#blue]-> stopped : Sync was stopped.

fetchUTXO : FetchUTXOAction
fetchUTXO -[#green,bold]-> handleSaplingParams
fetchUTXO -[#red]-> failed : Error occured.
fetchUTXO -[#blue]-> stopped : Sync was stopped.

handleSaplingParams : SaplingParamsAction
handleSaplingParams -[#green,bold]-> scanDownloaded
handleSaplingParams -[#red]-> failed : Error occured.
handleSaplingParams -[#blue]-> stopped : Sync was stopped.

scanDownloaded : ScanDownloadedButUnscannedAction
scanDownloaded -[#green,bold]-> download
scanDownloaded -[#red]-> failed : Error occured.
scanDownloaded -[#blue]-> stopped : Sync was stopped.

download : DownloadAction
download -[#green,bold]-> validate
download -[#red]-> failed : Error occured.
download -[#blue]-> stopped : Sync was stopped.

validate : ValidateAction
validate -[#green,bold]-> scan
validate -[#red]-> failed : Error occured.
validate -[#blue]-> stopped : Sync was stopped.

scan : ScanAction
scan -[#green,bold]-> clearAlreadyScannedBlocks
scan -[#red]-> failed : Error occured.
scan -[#blue]-> stopped : Sync was stopped.

clearAlreadyScannedBlocks : ClearAlreadyScannedBlocksAction
clearAlreadyScannedBlocks -[#green,bold]-> enhance
clearAlreadyScannedBlocks -[#red]-> failed : Error occured.
clearAlreadyScannedBlocks -[#blue]-> stopped : Sync was stopped.

enhance : EnhanceAction
enhance -[#green,bold]-> download : Not all blocks in the\nsync range are downloaded\nand scanned yet.
enhance -[#green,bold]-> clearCache : All the blocks in\nthe sync range are downloaded\nand scanned.
enhance -[#red]-> failed : Error occured.
enhance -[#blue]-> stopped : Sync was stopped.

note right of enhance
    Enhance transactions in batches of 1000 
    blocks. Dont't do it for each scan batch 
    which is usualy 100 blocks.
end note

clearCache : ClearCacheAction
clearCache --> finished
clearCache -[#red]-> failed : Error occured.
clearCache -[#blue]-> stopped : Sync was stopped.

finished --> [*]
failed --> [*]
stopped --> [*]

@enduml