{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE NoImplicitPrelude #-}

module Biz.Namespace
  ( Namespace (..),
    Ext (..),
    fromPath,
    toPath,
    toModule,
    fromHaskellContent,
    fromHaskellModule,
    toHaskellModule,
    toSchemeModule,
    fromPythonModule,
    isCab,
    groupByExt,
  )
where

import Alpha
import qualified Data.Aeson as Aeson
import qualified Data.Aeson.Types as Aeson
import qualified Data.Char as Char
import qualified Data.List as List
import qualified Data.List.Split as List
import qualified Data.Map as Map
import qualified Data.Text as Text
import qualified Text.Regex.Applicative as Regex

data Ext
  = Bash
  | C
  | Css
  | Hs
  | Html
  | Json
  | Keys
  | Lisp
  | Md
  | Nix
  | None
  | Py
  | Rs
  | Scm
  | Sh
  | Toml
  deriving (Eq, Show, Generic, Aeson.ToJSON, Ord)

data Namespace = Namespace {path :: [String], ext :: Ext}
  deriving (Eq, Show, Generic, Aeson.ToJSON, Ord)

instance Aeson.ToJSONKey Namespace where
  toJSONKey = Aeson.toJSONKeyText (Text.pack <. toPath)

fromPath :: String -> String -> Maybe Namespace
fromPath bizRoot absPath =
  List.stripPrefix bizRoot absPath
    +> List.stripPrefix "/"
    +> Regex.match (Namespace </ rePath <* dot <*> reExt)

toPath :: Namespace -> FilePath
toPath (Namespace parts ext) =
  joinWith "/" parts <> toExt ext

toExt :: Ext -> String
toExt =
  ("." <>) <. \case
    Bash -> "bash"
    C -> "c"
    Css -> "css"
    Hs -> "hs"
    Html -> "html"
    Json -> "json"
    Keys -> "pub"
    Lisp -> "lisp"
    Md -> "md"
    Nix -> "nix"
    None -> "none"
    Py -> "py"
    Rs -> "rs"
    Scm -> "scm"
    Sh -> "sh"
    Toml -> "toml"

fromHaskellContent :: String -> Maybe Namespace
fromHaskellContent c = case Regex.findFirstInfix haskellModule c of
  Nothing -> Nothing
  Just (_, Namespace {..}, _) -> Just <| Namespace (filter (/= ".") path) ext
  where
    haskellModule =
      Namespace
        </ (Regex.string "\nmodule " *> Regex.many (name <|> dot))
        <*> pure Hs

toModule :: Namespace -> String
toModule (Namespace parts Hs) = joinWith "." parts
toModule (Namespace parts Py) = joinWith "." parts
toModule (Namespace parts Scm) = "(" ++ joinWith " " parts ++ ")"
toModule (Namespace parts Rs) = joinWith "::" parts
toModule (Namespace parts C) = joinWith "/" parts <> ".c"
toModule (Namespace parts Nix) = joinWith "/" parts <> ".nix"
toModule (Namespace {..}) = panic <| "toModule not implemented for " <> show ext

toHaskellModule :: Namespace -> String
toHaskellModule = toModule

fromHaskellModule :: String -> Namespace
fromHaskellModule s = Namespace (List.splitOn "." s) Hs

toSchemeModule :: Namespace -> String
toSchemeModule = toModule

fromPythonModule :: String -> Namespace
fromPythonModule s = Namespace (List.splitOn "." s) Py

dot :: Regex.RE Char String
dot = Regex.some <| Regex.sym '.'

name :: Regex.RE Char String
name =
  Regex.many (Regex.psym Char.isUpper)
    <> ( Regex.many
           <| Regex.psym
           <| \c -> Char.isAlphaNum c || c == '_' || c == '-'
       )

rePath :: Regex.RE Char [String]
rePath = Regex.many (name <* Regex.string "/" <|> name)

reExt :: Regex.RE Char Ext
reExt =
  C <$ Regex.string "c"
    <|> Css <$ Regex.string "css"
    <|> Hs <$ Regex.string "hs"
    <|> Html <$ Regex.string "html"
    <|> Json <$ Regex.string "json"
    <|> Keys <$ Regex.string "pub"
    <|> Lisp <$ Regex.string "lisp"
    <|> Md <$ Regex.string "md"
    <|> Nix <$ Regex.string "nix"
    <|> Py <$ Regex.string "py"
    <|> Rs <$ Regex.string "rs"
    <|> Scm <$ Regex.string "scm"
    <|> Sh <$ Regex.string "sh"
    <|> Bash <$ Regex.string "bash"
    <|> Toml <$ Regex.string "toml"

-- | The cab dir is for temporary files and build outputs, not for source
-- inputs.
isCab :: FilePath -> Bool
isCab ('_' : _) = True
isCab fp = "/_/" `List.isInfixOf` fp

-- | Group a list of Namespaces keyed by their extensions
groupByExt :: [Namespace] -> Map Ext [Namespace]
groupByExt ns's = Map.fromListWith (++) [(ext ns, [ns]) | ns <- ns's]