-----------------------------------------------------------------------------
-- Copyright 2010, Open Universiteit Nederland. This file is distributed 
-- under the terms of the GNU General Public License. For more information, 
-- see the file "LICENSE.txt", which is included in the distribution.
-----------------------------------------------------------------------------
-- |
-- Maintainer  :  alex.gerdes@ou.nl
-- Stability   :  provisional
-- Portability :  portable (depends on ghc)
--
-----------------------------------------------------------------------------
module Domain.Math.Power.Equation.Exercises    
   ( powerEqExercise
   , expEqExercise
   , logEqExercise
   , higherPowerEqExercise
   ) where

import Prelude hiding ( (^) )

import Common.Context
import Common.Exercise
import Common.View
import Domain.Math.Data.OrList
import Domain.Math.Data.Relation
import Domain.Math.Equation.Views
import Domain.Math.Examples.DWO4
import Domain.Math.Expr hiding (isPower)
import Domain.Math.Numeric.Views
import Domain.Math.Power.Rules
import Domain.Math.Power.Equation.Strategies
import Domain.Math.Power.Equation.NormViews


------------------------------------------------------------
-- Exercises

powerEqExercise :: Exercise (Relation Expr)
powerEqExercise = let precision = 2 in makeExercise
  { status         = Provisional
  , parser         = parseExprWith (pRelation pExpr)
  , strategy       = powerEqApproxStrategy
  , navigation     = termNavigator
  , exerciseId     = describe "solve power equation algebraically with x > 0" $ 
                       newId "algebra.manipulation.exponents.equation"
  , examples       = concatMap (map $ build equationView) $ 
                       powerEquations ++ [last higherPowerEquations]
  , isReady        = solvedRelation
  , isSuitable   = (`belongsTo` (normPowerEqApproxView precision))
  , equivalence    = viewEquivalent (normPowerEqApproxView precision)
  }
  
expEqExercise :: Exercise (Equation Expr)
expEqExercise = makeExercise
  { status         = Provisional
  , parser         = parseExprWith (pEquation pExpr)
  , strategy       = expEqStrategy
  , navigation     = termNavigator
  , exerciseId     = describe "solve exponential equation algebraically" $ 
                       newId "algebra.manipulation.exponential.equation"
  , examples       = concat expEquations
  , isReady        = \ rel -> isVariable (leftHandSide rel) 
                           && rightHandSide rel `belongsTo` rationalView
  , isSuitable     = (`belongsTo` normExpEqView)
  , equivalence    = viewEquivalent normExpEqView
  , ruleOrdering   = ruleOrderingWithId [ getId root2power ]  
  }

logEqExercise :: Exercise (OrList (Relation Expr))
logEqExercise = makeExercise
  { status         = Provisional
  , parser         = parseExprWith (pOrList (pRelation pExpr))
  , strategy       = logEqStrategy
  , navigation     = termNavigator
  , exerciseId     = describe "solve logarithmic equation algebraically" $ 
                       newId "algebra.manipulation.logarithmic.equation"
  , examples       = map (orList . return . build equationView) (concat logEquations)
  , isReady        = solvedRelations
  , isSuitable     = (`belongsTo` (switchView equationView >>> normLogEqView))
  , equivalence    = viewEquivalent (switchView equationView >>> normLogEqView)
  , ruleOrdering   = ruleOrderingWithId [ getId calcPower
                                        , getId calcRoot ]
  }

higherPowerEqExercise :: Exercise (OrList (Equation Expr))
higherPowerEqExercise = makeExercise
  { status         = Provisional
  , parser         = parseExprWith (pOrList (pEquation pExpr))
  , strategy       = higherPowerEqStrategy
  , navigation     = termNavigator
  , exerciseId     = describe "solve higher power equation algebraically" $ 
                       newId "algebra.manipulation.exponents.equation"
  , examples       = map (orList . return) $ concat $ init higherPowerEquations
  , isReady        = solvedRelations
  , isSuitable     = maybe False and . disjunctions . fmap (`belongsTo` normPowerEqView)
  , equivalence    = let f = normalize . fmap (simplify normPowerEqView')
                     in \ x y -> f x == f y
  , ruleOrdering   = ruleOrderingWithId [ getId calcPower
                                        , getId calcRoot ]
  }