/-
Copyright (c) 2022 Henrik Böving. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Henrik Böving
-/
import Lean

import DocGen4.Process.Base
import DocGen4.Process.NameInfo
import DocGen4.Process.DefinitionInfo

namespace DocGen4.Process

open Lean Meta

def getInstanceTypes (typ : Expr) : MetaM (Array Name) := do
  let (_, _, tail) ← forallMetaTelescopeReducing typ
  let args := tail.getAppArgs
  let (_, bis, _) ← forallMetaTelescopeReducing (← inferType tail.getAppFn)
  let (_, names) ← (bis.zip args).mapM findName |>.run .empty
  return names
where
  findName : BinderInfo × Expr → StateRefT (Array Name) MetaM Unit
    | (.default, .sort .zero) => modify (·.push "_builtin_prop")
    | (.default, .sort (.succ _)) => modify (·.push "_builtin_typeu")
    | (.default, .sort _) => modify (·.push "_builtin_sortu")
    | (.default, e) =>
      match e.getAppFn with
      | .const name .. => modify (·.push name)
      | _ => return ()
    | _ => return ()

def InstanceInfo.ofDefinitionVal (v : DefinitionVal) : MetaM InstanceInfo := do
  let mut info ← DefinitionInfo.ofDefinitionVal v
  let some className ← isClass? v.type | panic! s!"isClass? on {v.name} returned none"
  if let some instAttr ← getDefaultInstance v.name className then
    info := { info with attrs := info.attrs.push instAttr }
  let typeNames ← getInstanceTypes v.type
  return {
    toDefinitionInfo := info,
    className,
    typeNames
  }

end DocGen4.Process