{- This file is part of Vervis.
 -
 - Written in 2016 by fr33domlover <fr33domlover@riseup.net>.
 -
 - ♡ Copying is an act of love. Please copy, reuse and share.
 -
 - The author(s) have dedicated all copyright and related and neighboring
 - rights to this software to the public domain worldwide. This software is
 - distributed without any warranty.
 -
 - You should have received a copy of the CC0 Public Domain Dedication along
 - with this software. If not, see
 - <http://creativecommons.org/publicdomain/zero/1.0/>.
 -}

module Vervis.Handler.Repo
    ( getReposR
    , postReposR
    , getRepoNewR
    , getRepoR
    , getRepoCommitsR
    )
where

--TODO CONTINUE HERE
--
-- [/] maybe list project repos in personal overview too
-- [x] make repo list page
-- [x] add new repo creation link
-- [x] make new repo form
-- [x] write the git and mkdir parts that actually create the repo
-- [x] make repo view that shows a table of commits

import ClassyPrelude.Conduit       hiding (unpack)
import Yesod                       hiding (Header, parseTime, (==.))
import Yesod.Auth

import Data.Git.Graph
import Data.Git.Graph.Util
import Data.Git.Ref (toHex)
import Data.Git.Repository (initRepo)
import Data.Git.Storage (withRepo)
import Data.Git.Types (Commit (..), Person (..))
import Data.Graph.Inductive.Graph (noNodes)
import Data.Graph.Inductive.Query.Topsort
import Data.Text (unpack)
import Data.Text.Encoding (decodeUtf8With)
import Data.Text.Encoding.Error (lenientDecode)
import Database.Esqueleto
import Data.Hourglass (timeConvert)
import System.Directory (createDirectoryIfMissing)
import System.Hourglass (dateCurrent)

import qualified Data.DList as D

import Data.ByteString.Char8.Local (takeLine)
import Vervis.Form.Repo
import Vervis.Foundation
import Vervis.Git (timeAgo')
import Vervis.Path
import Vervis.Model
import Vervis.Settings

getReposR :: Text -> Text -> Handler Html
getReposR user proj = do
    repos <- runDB $ select $ from $ \ (sharer, project, repo) -> do
        where_ $
            sharer ^. SharerIdent ==. val user &&.
            sharer ^. SharerId ==. project ^. ProjectSharer &&.
            repo ^. RepoProject ==. project ^. ProjectId
        orderBy [asc $ repo ^. RepoIdent]
        return $ repo ^. RepoIdent
    defaultLayout $ do
        setTitle $ toHtml $ mconcat
            ["Vervis > People > ", user, " > Projects > ", proj, " Repos"]
        $(widgetFile "repo/repos")

postReposR :: Text -> Text -> Handler Html
postReposR user proj = do
    Entity _pid person <- requireAuth
    let sid = personIdent person
    Entity pid _project <- runDB $ getBy404 $ UniqueProject proj sid
    ((result, widget), enctype) <- runFormPost $ newRepoForm sid pid
    case result of
        FormSuccess repo -> do
            parent <- askProjectDir user proj
            let path = parent </> unpack (repoIdent repo)
            liftIO $ createDirectoryIfMissing True parent
            liftIO $ initRepo $ fromString path
            runDB $ insert_ repo
            setMessage "Repo added."
            redirectUltDest HomeR
        FormMissing -> do
            setMessage "Field(s) missing"
            defaultLayout $(widgetFile "repo/repo-new")
        FormFailure l -> do
            setMessage $ toHtml $ intercalate "; " l
            defaultLayout $(widgetFile "repo/repo-new")

getRepoNewR :: Text -> Text -> Handler Html
getRepoNewR user proj = do
    Entity _pid person <- requireAuth
    let sid = personIdent person
    Entity pid _project <- runDB $ getBy404 $ UniqueProject proj sid
    ((_result, widget), enctype) <- runFormPost $ newRepoForm sid pid
    defaultLayout $ do
        setTitle $ toHtml $ mconcat
            ["Vervis > People > ", user, " > Projects > ", proj, " > New Repo"]
        $(widgetFile "repo/repo-new")

instance ResultList D.DList where
    emptyList = D.empty
    appendItem = flip D.snoc

getRepoR :: Text -> Text -> Text -> Handler Html
getRepoR user proj repo = do
    repository <- runDB $ do
        Entity sid _s <- getBy404 $ UniqueSharerIdent user
        Entity pid _p <- getBy404 $ UniqueProject proj sid
        Entity _rid r <- getBy404 $ UniqueRepo repo pid
        return r
    path <- askRepoDir user proj repo
    pairs <- liftIO $ withRepo (fromString path) $ \ git -> do
        oid <- resolveName git $ unpack $ repoMainBranch repository
        graph <- loadCommitGraphPT git [oid]
        let mnodes = topsortUnmixOrder graph (NodeStack [noNodes graph])
            nodes = case mnodes of
                Nothing -> error "commit graph contains a cycle"
                Just ns -> ns
        return $ D.toList $ fmap (nodeLabel graph) nodes
    now <- liftIO dateCurrent
    let toText = decodeUtf8With lenientDecode
        mkrow oid commit =
            ( toText $ personName $ commitAuthor commit
            , toText $ toHex $ unObjId oid
            , toText $ takeLine $ commitMessage commit
            , timeAgo' now (timeConvert $ personTime $ commitAuthor commit)
            )
        rows = map (uncurry mkrow) pairs
    defaultLayout $ do
        setTitle $ toHtml $ intercalate " > " $
            ["Vervis", "People", user, "Projects", proj, "Repos", repo]
        $(widgetFile "repo/repo")

getRepoCommitsR :: Text -> Text -> Text -> Handler Html
getRepoCommitsR user proj repo = do
    repository <- runDB $ do
        Entity sid _s <- getBy404 $ UniqueSharerIdent user
        Entity pid _p <- getBy404 $ UniqueProject proj sid
        Entity _rid r <- getBy404 $ UniqueRepo repo pid
        return r
    path <- askRepoDir user proj repo
    pairs <- liftIO $ withRepo (fromString path) $ \ git -> do
        oid <- resolveName git $ unpack $ repoMainBranch repository
        graph <- loadCommitGraphPT git [oid]
        let mnodes = topsortUnmixOrder graph (NodeStack [noNodes graph])
            nodes = case mnodes of
                Nothing -> error "commit graph contains a cycle"
                Just ns -> ns
        return $ D.toList $ fmap (nodeLabel graph) nodes
    now <- liftIO dateCurrent
    let toText = decodeUtf8With lenientDecode
        mkrow oid commit =
            ( toText $ personName $ commitAuthor commit
            , toText $ toHex $ unObjId oid
            , toText $ takeLine $ commitMessage commit
            , timeAgo' now (timeConvert $ personTime $ commitAuthor commit)
            )
        rows = map (uncurry mkrow) pairs
    defaultLayout $ do
        setTitle $ toHtml $ intercalate " > " $
            ["Vervis", "People", user, "Projects", proj, "Repos", repo, "Commits"]
        $(widgetFile "repo/commits")