{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}

-- | Gerrit stream event data type
module Gerrit.Data.Event
  ( -- * Main event data types
    EventType (..),
    Event (..),

    -- * Common data types
    User (..),
    PatchSet (..),
    Change (..),
    Ref (..),

    -- * Individual event data types
    AssigneeChanged (..),
    ChangeAbandoned (..),
    ChangeDeleted (..),
    ChangeMerged (..),
    ChangeRestored (..),
    CommentAdded (..),
    HashtagsChanged (..),
    ProjectCreated (..),
    PatchsetCreated (..),
    RefUpdated (..),
    ReviewerAdded (..),
    ReviewerDeleted (..),
    TopicChanged (..),
    WorkInProgressStateChanged (..),
    PrivateStateChanged (..),
    VoteDeleted (..),

    -- * Convenient functions
    getChange,
    getPatchSet,
    getUser,
    getCreatedOn,
    getEventType,
    eventName,
  )
where

import Control.Monad (mzero)
import Data.Aeson
  ( FromJSON (..),
    Options (fieldLabelModifier),
    Value (Object, String),
    defaultOptions,
    genericParseJSON,
    (.:),
  )
import Data.Char (toLower)
import Data.Text (Text)
import qualified Data.Text as Text
import GHC.Generics (Generic)
import GHC.Int (Int64)

aesonOption :: Text -> Options
aesonOption prefix = defaultOptions {fieldLabelModifier = recordToJson}
  where
    recordToJson = updateCase . drop (Text.length prefix)
    updateCase [] = []
    updateCase (x : xs) = toLower x : xs

-------------------------------------------------------------------------------
-- Shared types
-------------------------------------------------------------------------------
data User = User
  { userName :: Maybe Text,
    userEmail :: Maybe Text,
    userUsername :: Maybe Text
  }
  deriving (Show, Eq, Generic)

instance FromJSON User where
  parseJSON = genericParseJSON $ aesonOption "user"

data PatchSet = PatchSet
  { patchSetNumber :: Int,
    patchSetRef :: Text,
    patchSetUploader :: User,
    patchsetAuthor :: User
  }
  deriving (Show, Eq, Generic)

instance FromJSON PatchSet where
  parseJSON = genericParseJSON $ aesonOption "patchSet"

data Change = Change
  { changeProject :: Text,
    changeBranch :: Text,
    changeSubject :: Text,
    changeNumber :: Int,
    changeUrl :: Text,
    changeOwner :: User,
    changeWip :: Maybe Bool,
    changeTopic :: Maybe Text,
    changeCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

instance FromJSON Change where
  parseJSON = genericParseJSON $ aesonOption "change"

data Ref = Ref
  { refOldRev :: Text,
    refNewRev :: Text,
    refRefName :: Text,
    refProject :: Text
  }
  deriving (Show, Eq, Generic)

instance FromJSON Ref where
  parseJSON = genericParseJSON $ aesonOption "ref"

-------------------------------------------------------------------------------
-- Individual Event data types
-------------------------------------------------------------------------------
data AssigneeChanged = AssigneeChanged
  { assigneeChangedChange :: Change,
    assigneeChangedChanger :: User,
    assigneeChangedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data ChangeAbandoned = ChangeAbandoned
  { changeAbandonedProject :: Text,
    changeAbandonedAbandoner :: User,
    changeAbandonedChange :: Change,
    changeAbandonedPatchSet :: PatchSet,
    changeAbandonedReason :: Maybe Text,
    changeAbandonedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data ChangeDeleted = ChangeDeleted
  { changeDeletedChange :: Change,
    changeDeletedDeleter :: User
  }
  deriving (Show, Eq, Generic)

data ChangeMerged = ChangeMerged
  { changeMergedProject :: Text,
    changeMergedSubmitter :: User,
    changeMergedChange :: Change,
    changeMergedPatchSet :: PatchSet,
    changeMergedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data ChangeRestored = ChangeRestored
  { changeRestoredChange :: Change,
    changeRestoredPatchSet :: PatchSet,
    changeRestoredRestorer :: User,
    changeRestoredReason :: Maybe Text,
    changeRestoredEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data CommentAdded = CommentAdded
  { commentAddedChange :: Change,
    commentAddedPatchSet :: PatchSet,
    commentAddedAuthor :: User,
    commentAddedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data HashtagsChanged = HashtagsChanged
  { hashtagsChangedChange :: Change,
    hashtagsChangedEditor :: User,
    hashtagsChangedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data ProjectCreated = ProjectCreated
  { projectCreatedProjectName :: Text,
    projectCreatedHeadName :: Text,
    projectCreatedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data PatchsetCreated = PatchsetCreated
  { patchsetCreatedUploader :: User,
    patchsetCreatedChange :: Change,
    patchsetCreatedPatchSet :: PatchSet,
    patchsetCreatedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data RefUpdated = RefUpdated
  { refUpdatedSubmitter :: User,
    refUpdatedRefUpdate :: Ref,
    refUpdatedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data ReviewerAdded = ReviewerAdded
  { reviewerAddedChange :: Change,
    reviewerAddedPatchSet :: PatchSet,
    reviewerAddedAdder :: User,
    reviewerAddedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data ReviewerDeleted = ReviewerDeleted
  { reviewerDeletedChange :: Change,
    reviewerDeletedPatchSet :: PatchSet,
    reviewerDeletedRemover :: User,
    reviewerDeletedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data TopicChanged = TopicChanged
  { topicChangedChange :: Change,
    topicChangedChanger :: User,
    topicChangedOldTopic :: Text,
    topicChangedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data WorkInProgressStateChanged = WorkInProgressStateChanged
  { workInProgressStateChangedChange :: Change,
    workInProgressStateChangedPatchSet :: PatchSet,
    workInProgressStateChangedChanger :: User,
    workInProgressStateChangedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data PrivateStateChanged = PrivateStateChanged
  { privateStateChangedChange :: Change,
    privateStateChangedPatchSet :: PatchSet,
    privateStateChangedChanger :: User,
    privateStateChangedChangedEventCreatedOn :: Int64
  }
  deriving (Show, Eq, Generic)

data VoteDeleted = VoteDeleted
  { voteDeletedChange :: Change,
    voteDeletedPatchSet :: PatchSet,
    voteDeletedRemover :: User
  }
  deriving (Show, Eq, Generic)

-------------------------------------------------------------------------------
-- Events FromJSON instances
-------------------------------------------------------------------------------
instance FromJSON AssigneeChanged where
  parseJSON = genericParseJSON $ aesonOption "assigneeChanged"

instance FromJSON ChangeAbandoned where
  parseJSON = genericParseJSON $ aesonOption "changeAbandoned"

instance FromJSON ChangeDeleted where
  parseJSON = genericParseJSON $ aesonOption "changeDeleted"

instance FromJSON ChangeMerged where
  parseJSON = genericParseJSON $ aesonOption "changeMerged"

instance FromJSON ChangeRestored where
  parseJSON = genericParseJSON $ aesonOption "changeRestored"

instance FromJSON CommentAdded where
  parseJSON = genericParseJSON $ aesonOption "commentAdded"

instance FromJSON HashtagsChanged where
  parseJSON = genericParseJSON $ aesonOption "hashtagsChanged"

instance FromJSON ProjectCreated where
  parseJSON = genericParseJSON $ aesonOption "projectCreated"

instance FromJSON PatchsetCreated where
  parseJSON = genericParseJSON $ aesonOption "patchsetCreated"

instance FromJSON RefUpdated where
  parseJSON = genericParseJSON $ aesonOption "refUpdated"

instance FromJSON ReviewerAdded where
  parseJSON = genericParseJSON $ aesonOption "reviewerAdded"

instance FromJSON ReviewerDeleted where
  parseJSON = genericParseJSON $ aesonOption "reviewerDeleted"

instance FromJSON TopicChanged where
  parseJSON = genericParseJSON $ aesonOption "topicChanged"

instance FromJSON WorkInProgressStateChanged where
  parseJSON = genericParseJSON $ aesonOption "workInProgressStateChanged"

instance FromJSON PrivateStateChanged where
  parseJSON = genericParseJSON $ aesonOption "privateStateChanged"

instance FromJSON VoteDeleted where
  parseJSON = genericParseJSON $ aesonOption "voteDeleted"

-- | The event "type" data type
data EventType
  = AssigneeChangedEvent
  | ChangeAbandonedEvent
  | ChangeDeletedEvent
  | ChangeMergedEvent
  | ChangeRestoredEvent
  | CommentAddedEvent
  | DroppedOutputEvent
  | HashtagsChangedEvent
  | ProjectCreatedEvent
  | PatchsetCreatedEvent
  | RefUpdatedEvent
  | ReviewerAddedEvent
  | ReviewerDeletedEvent
  | TopicChangedEvent
  | WorkInProgressStateChangedEvent
  | PrivateStateChangedEvent
  | VoteDeletedEvent
  deriving (Show, Eq)

instance FromJSON EventType where
  parseJSON (String v) = case v of
    "assignee-changed" -> pure AssigneeChangedEvent
    "change-abandoned" -> pure ChangeAbandonedEvent
    "change-deleted" -> pure ChangeDeletedEvent
    "change-merged" -> pure ChangeMergedEvent
    "change-restored" -> pure ChangeRestoredEvent
    "comment-added" -> pure CommentAddedEvent
    "dropped-output" -> pure DroppedOutputEvent
    "hashtags-changed" -> pure HashtagsChangedEvent
    "project-created" -> pure ProjectCreatedEvent
    "patchset-created" -> pure PatchsetCreatedEvent
    "ref-updated" -> pure RefUpdatedEvent
    "reviewer-added" -> pure ReviewerAddedEvent
    "reviewer-deleted" -> pure ReviewerDeletedEvent
    "topic-changed" -> pure TopicChangedEvent
    "wip-state-changed" -> pure WorkInProgressStateChangedEvent
    "private-state-changed" -> pure PrivateStateChangedEvent
    "vote-deleted" -> pure VoteDeletedEvent
    _ -> mzero
  parseJSON _ = mzero

-- | The main event union data type
data Event
  = EventAssigneeChanged AssigneeChanged
  | EventChangeAbandoned ChangeAbandoned
  | EventChangeDeleted ChangeDeleted
  | EventChangeMerged ChangeMerged
  | EventChangeRestored ChangeRestored
  | EventCommentAdded CommentAdded
  | EventDroppedOutput
  | EventHashtagsChanged HashtagsChanged
  | EventProjectCreated ProjectCreated
  | EventPatchsetCreated PatchsetCreated
  | EventRefUpdated RefUpdated
  | EventReviewerAdded ReviewerAdded
  | EventReviewerDeleted ReviewerDeleted
  | EventTopicChanged TopicChanged
  | EventWorkInProgressStateChanged WorkInProgressStateChanged
  | EventPrivateStateChanged PrivateStateChanged
  | EventVoteDeleted VoteDeleted
  deriving (Show, Eq)

instance FromJSON Event where
  parseJSON o@(Object v) = do
    eType <- v .: "type"
    case eType of
      AssigneeChangedEvent -> EventAssigneeChanged <$> parseJSON o
      ChangeAbandonedEvent -> EventChangeAbandoned <$> parseJSON o
      ChangeDeletedEvent -> EventChangeDeleted <$> parseJSON o
      ChangeMergedEvent -> EventChangeMerged <$> parseJSON o
      ChangeRestoredEvent -> EventChangeRestored <$> parseJSON o
      CommentAddedEvent -> EventCommentAdded <$> parseJSON o
      DroppedOutputEvent -> pure EventDroppedOutput
      HashtagsChangedEvent -> EventHashtagsChanged <$> parseJSON o
      ProjectCreatedEvent -> EventProjectCreated <$> parseJSON o
      PatchsetCreatedEvent -> EventPatchsetCreated <$> parseJSON o
      RefUpdatedEvent -> EventRefUpdated <$> parseJSON o
      ReviewerAddedEvent -> EventReviewerAdded <$> parseJSON o
      ReviewerDeletedEvent -> EventReviewerDeleted <$> parseJSON o
      TopicChangedEvent -> EventTopicChanged <$> parseJSON o
      WorkInProgressStateChangedEvent -> EventWorkInProgressStateChanged <$> parseJSON o
      PrivateStateChangedEvent -> EventPrivateStateChanged <$> parseJSON o
      VoteDeletedEvent -> EventVoteDeleted <$> parseJSON o
  parseJSON _ = mzero

-------------------------------------------------------------------------------
-- Utilities function
-------------------------------------------------------------------------------

-- | Get the associated change
getChange :: Event -> Maybe Change
getChange event = case event of
  EventAssigneeChanged AssigneeChanged {..} -> Just assigneeChangedChange
  EventChangeAbandoned ChangeAbandoned {..} -> Just changeAbandonedChange
  EventChangeDeleted ChangeDeleted {..} -> Just changeDeletedChange
  EventChangeMerged ChangeMerged {..} -> Just changeMergedChange
  EventChangeRestored ChangeRestored {..} -> Just changeRestoredChange
  EventCommentAdded CommentAdded {..} -> Just commentAddedChange
  EventDroppedOutput -> Nothing
  EventHashtagsChanged HashtagsChanged {..} -> Just hashtagsChangedChange
  EventProjectCreated _ -> Nothing
  EventPatchsetCreated PatchsetCreated {..} -> Just patchsetCreatedChange
  EventRefUpdated _ -> Nothing
  EventReviewerAdded ReviewerAdded {..} -> Just reviewerAddedChange
  EventReviewerDeleted ReviewerDeleted {..} -> Just reviewerDeletedChange
  EventTopicChanged TopicChanged {..} -> Just topicChangedChange
  EventWorkInProgressStateChanged WorkInProgressStateChanged {..} -> Just workInProgressStateChangedChange
  EventPrivateStateChanged PrivateStateChanged {..} -> Just privateStateChangedChange
  EventVoteDeleted VoteDeleted {..} -> Just voteDeletedChange

-- | Get the associated patchset
getPatchSet :: Event -> Maybe PatchSet
getPatchSet event = case event of
  EventAssigneeChanged _ -> Nothing
  EventChangeAbandoned ChangeAbandoned {..} -> Just changeAbandonedPatchSet
  EventChangeDeleted _ -> Nothing
  EventChangeMerged ChangeMerged {..} -> Just changeMergedPatchSet
  EventChangeRestored ChangeRestored {..} -> Just changeRestoredPatchSet
  EventCommentAdded CommentAdded {..} -> Just commentAddedPatchSet
  EventDroppedOutput -> Nothing
  EventHashtagsChanged _ -> Nothing
  EventProjectCreated _ -> Nothing
  EventPatchsetCreated PatchsetCreated {..} -> Just patchsetCreatedPatchSet
  EventRefUpdated _ -> Nothing
  EventReviewerAdded ReviewerAdded {..} -> Just reviewerAddedPatchSet
  EventReviewerDeleted ReviewerDeleted {..} -> Just reviewerDeletedPatchSet
  EventTopicChanged _ -> Nothing
  EventWorkInProgressStateChanged WorkInProgressStateChanged {..} -> Just workInProgressStateChangedPatchSet
  EventPrivateStateChanged PrivateStateChanged {..} -> Just privateStateChangedPatchSet
  EventVoteDeleted VoteDeleted {..} -> Just voteDeletedPatchSet

-- | Get the associated author
getUser :: Event -> Maybe User
getUser event = case event of
  EventAssigneeChanged AssigneeChanged {..} -> Just assigneeChangedChanger
  EventChangeAbandoned ChangeAbandoned {..} -> Just changeAbandonedAbandoner
  EventChangeDeleted ChangeDeleted {..} -> Just changeDeletedDeleter
  EventChangeMerged ChangeMerged {..} -> Just changeMergedSubmitter
  EventChangeRestored ChangeRestored {..} -> Just changeRestoredRestorer
  EventCommentAdded CommentAdded {..} -> Just commentAddedAuthor
  EventDroppedOutput -> Nothing
  EventHashtagsChanged HashtagsChanged {..} -> Just hashtagsChangedEditor
  EventProjectCreated _ -> Nothing
  EventPatchsetCreated PatchsetCreated {..} -> Just patchsetCreatedUploader
  EventRefUpdated _ -> Nothing
  EventReviewerAdded ReviewerAdded {..} -> Just reviewerAddedAdder
  EventReviewerDeleted ReviewerDeleted {..} -> Just reviewerDeletedRemover
  EventTopicChanged TopicChanged {..} -> Just topicChangedChanger
  EventWorkInProgressStateChanged WorkInProgressStateChanged {..} -> Just workInProgressStateChangedChanger
  EventPrivateStateChanged PrivateStateChanged {..} -> Just privateStateChangedChanger
  EventVoteDeleted VoteDeleted {..} -> Just voteDeletedRemover

-- | Get the creation timestamp
getCreatedOn :: Event -> Maybe Int64
getCreatedOn event = case event of
  EventAssigneeChanged AssigneeChanged {..} -> Just assigneeChangedEventCreatedOn
  EventChangeAbandoned ChangeAbandoned {..} -> Just changeAbandonedEventCreatedOn
  EventChangeDeleted _ -> Nothing
  EventChangeMerged ChangeMerged {..} -> Just changeMergedEventCreatedOn
  EventChangeRestored ChangeRestored {..} -> Just changeRestoredEventCreatedOn
  EventCommentAdded CommentAdded {..} -> Just commentAddedEventCreatedOn
  EventDroppedOutput -> Nothing
  EventHashtagsChanged HashtagsChanged {..} -> Just hashtagsChangedEventCreatedOn
  EventProjectCreated ProjectCreated {..} -> Just projectCreatedEventCreatedOn
  EventPatchsetCreated PatchsetCreated {..} -> Just patchsetCreatedEventCreatedOn
  EventRefUpdated RefUpdated {..} -> Just refUpdatedEventCreatedOn
  EventReviewerAdded ReviewerAdded {..} -> Just reviewerAddedEventCreatedOn
  EventReviewerDeleted ReviewerDeleted {..} -> Just reviewerDeletedEventCreatedOn
  EventTopicChanged TopicChanged {..} -> Just topicChangedEventCreatedOn
  EventWorkInProgressStateChanged WorkInProgressStateChanged {..} -> Just workInProgressStateChangedEventCreatedOn
  EventPrivateStateChanged PrivateStateChanged {..} -> Just privateStateChangedChangedEventCreatedOn
  EventVoteDeleted _ -> Nothing

-- | Get the 'EventType' back from an 'Event'
getEventType :: Event -> EventType
getEventType event = case event of
  EventAssigneeChanged _ -> AssigneeChangedEvent
  EventChangeAbandoned _ -> ChangeAbandonedEvent
  EventChangeDeleted _ -> ChangeDeletedEvent
  EventChangeMerged _ -> ChangeMergedEvent
  EventChangeRestored _ -> ChangeRestoredEvent
  EventCommentAdded _ -> CommentAddedEvent
  EventDroppedOutput -> DroppedOutputEvent
  EventHashtagsChanged _ -> HashtagsChangedEvent
  EventProjectCreated _ -> ProjectCreatedEvent
  EventPatchsetCreated _ -> PatchsetCreatedEvent
  EventRefUpdated _ -> RefUpdatedEvent
  EventReviewerAdded _ -> ReviewerAddedEvent
  EventReviewerDeleted _ -> ReviewerDeletedEvent
  EventTopicChanged _ -> TopicChangedEvent
  EventWorkInProgressStateChanged _ -> WorkInProgressStateChangedEvent
  EventPrivateStateChanged _ -> PrivateStateChangedEvent
  EventVoteDeleted _ -> VoteDeletedEvent

-- | Get the text representation suitable for event subscription.
eventName :: EventType -> Text
eventName eventType = case eventType of
  AssigneeChangedEvent -> "assignee-changed"
  ChangeAbandonedEvent -> "change-abandoned"
  ChangeDeletedEvent -> "change-deleted"
  ChangeMergedEvent -> "change-merged"
  ChangeRestoredEvent -> "change-restored"
  CommentAddedEvent -> "comment-added"
  DroppedOutputEvent -> "dropped-output"
  HashtagsChangedEvent -> "hashtags-changed"
  ProjectCreatedEvent -> "project-created"
  PatchsetCreatedEvent -> "patchset-created"
  RefUpdatedEvent -> "ref-updated"
  ReviewerAddedEvent -> "reviewer-added"
  ReviewerDeletedEvent -> "reviewer-deleted"
  TopicChangedEvent -> "topic-changed"
  WorkInProgressStateChangedEvent -> "wip-state-changed"
  PrivateStateChangedEvent -> "private-state-changed"
  VoteDeletedEvent -> "vote-deleted"