with Ada.Containers.Generic_Array_Sort;
with Ada.Containers.Hashed_Maps;
with Ada.Containers.Vectors;
with Ada.Strings.Unbounded.Hash;
with Ada.Unchecked_Deallocation;

with TOML.Generic_Dump;
with TOML.Generic_Parse;

package body TOML is

   use Ada.Strings.Unbounded;

   procedure Dump_To_String is new TOML.Generic_Dump
     (Output_Stream => Unbounded_UTF8_String,
      Put           => Append);

   procedure Sort_Keys is new Ada.Containers.Generic_Array_Sort
     (Index_Type   => Positive,
      Element_Type => Unbounded_UTF8_String,
      Array_Type   => Key_Array);

   package TOML_Maps is new Ada.Containers.Hashed_Maps
     (Key_Type        => Unbounded_String,
      Element_Type    => TOML_Value,
      Hash            => Hash,
      Equivalent_Keys => "=");

   package TOML_Vectors is new Ada.Containers.Vectors (Positive, TOML_Value);

   type TOML_Value_Record (Kind : Any_Value_Kind) is limited record
      Ref_Count : Natural;

      case Kind is
         when TOML_Table =>
            Map_Value : TOML_Maps.Map;

            Table_Implicitly_Created : Boolean;
            --  Helper for parsing: true iff this table was created implictly
            --  when parsing a sub-table. For instance, this is true for the
            --  table "a" if we read "[a.b]" but not yet "[a]".

         when TOML_Array =>
            Array_Value : TOML_Vectors.Vector;
            --  List of values for all items

            Array_Implicitly_Created : Boolean;
            --  Same as Table_Implicitly_Created

         when TOML_String =>
            String_Value : Unbounded_String;

         when TOML_Integer =>
            Integer_Value : Any_Integer;

         when TOML_Float =>
            Float_Value : Any_Float;

         when TOML_Boolean =>
            Boolean_Value : Boolean;

         when TOML_Offset_Datetime =>
            Offset_Datetime_Value : Any_Offset_Datetime;

         when TOML_Local_Datetime =>
            Local_Datetime_Value : Any_Local_Datetime;

         when TOML_Local_Date =>
            Local_Date_Value : Any_Local_Date;

         when TOML_Local_Time =>
            Local_Time_Value : Any_Local_Time;
      end case;
   end record;

   procedure Free is new Ada.Unchecked_Deallocation
     (TOML_Value_Record, TOML_Value_Record_Access);

   function Create_Value (Rec : TOML_Value_Record_Access) return TOML_Value;
   --  Wrap a value record in a value. This resets its ref-count to 1.

   ------------------
   -- Create_Value --
   ------------------

   function Create_Value (Rec : TOML_Value_Record_Access) return TOML_Value is
   begin
      return Result : TOML_Value do
         Rec.Ref_Count := 1;
         Result.Value := Rec;
      end return;
   end Create_Value;

   ------------------
   -- Create_Error --
   ------------------

   function Create_Error
     (Message : String; Location : Source_Location) return Read_Result is
   begin
      return
        (Success  => False,
         Message  => To_Unbounded_String (Message),
         Location => Location);
   end Create_Error;

   -------------
   -- Is_Null --
   -------------

   function Is_Null (Value : TOML_Value) return Boolean is
   begin
      return Value.Value = null;
   end Is_Null;

   ----------
   -- Kind --
   ----------

   function Kind (Value : TOML_Value) return Any_Value_Kind is
   begin
      return Value.Value.Kind;
   end Kind;

   ------------
   -- Equals --
   ------------

   function Equals (Left, Right : TOML_Value) return Boolean is
   begin
      --  If Left and Right refer to the same document, they are obviously
      --  equivalent (X is equivalent to X). If they don't have the same kind,
      --  they are obviously not equivalent.

      if Left = Right then
         return True;
      elsif Left.Kind /= Right.Kind then
         return False;
      end if;

      case Left.Kind is
         when TOML_Table =>
            declare
               Left_Keys  : constant Key_Array := Left.Keys;
               Right_Keys : constant Key_Array := Right.Keys;
            begin
               if Left_Keys /= Right_Keys then
                  return False;
               end if;

               for K of Left_Keys loop
                  if not Equals (Left.Get (K), Right.Get (K)) then
                     return False;
                  end if;
               end loop;
            end;

         when TOML_Array =>
            if Left.Length /= Right.Length then
               return False;
            end if;

            for I in 1 .. Left.Length loop
               if not Equals (Left.Item (I), Right.Item (I)) then
                  return False;
               end if;
            end loop;

         when TOML_String =>
            return Left.Value.String_Value = Right.Value.String_Value;

         when TOML_Integer =>
            return Left.Value.Integer_Value = Right.Value.Integer_Value;

         when TOML_Boolean =>
            return Left.Value.Boolean_Value = Right.Value.Boolean_Value;

         when TOML_Offset_Datetime =>
            return Left.Value.Offset_Datetime_Value
                   = Right.Value.Offset_Datetime_Value;

         when TOML_Local_Datetime =>
            return Left.Value.Local_Datetime_Value
                   = Right.Value.Local_Datetime_Value;

         when TOML_Local_Date =>
            return Left.Value.Local_Date_Value = Right.Value.Local_Date_Value;

         when TOML_Local_Time =>
            return Left.Value.Local_Time_Value = Right.Value.Local_Time_Value;

         when TOML_Float =>
            return Left.Value.Float_Value = Right.Value.Float_Value;
      end case;

      return True;
   end Equals;

   -----------
   -- Clone --
   -----------

   function Clone (Value : TOML_Value) return TOML_Value is
      Result : TOML_Value;
   begin
      case Value.Kind is
         when TOML_Table =>
            Result := Create_Table;
            for Key of Value.Keys loop
               Result.Set (Key, Value.Get (Key).Clone);
            end loop;

         when TOML_Array =>
            Result := Create_Array;
            for I in 1 .. Value.Length loop
               Result.Append (Value.Item (I));
            end loop;

         when TOML_String =>
            Result := Create_String (Value.Value.String_Value);

         when TOML_Integer =>
            Result := Create_Integer (Value.Value.Integer_Value);

         when TOML_Boolean =>
            Result := Create_Boolean (Value.Value.Boolean_Value);

         when TOML_Offset_Datetime =>
            Result :=
               Create_Offset_Datetime (Value.Value.Offset_Datetime_Value);

         when TOML_Local_Datetime =>
            Result := Create_Local_Datetime (Value.Value.Local_Datetime_Value);

         when TOML_Local_Date =>
            Result := Create_Local_Date (Value.Value.Local_Date_Value);

         when TOML_Local_Time =>
            Result := Create_Local_Time (Value.Value.Local_Time_Value);

         when TOML_Float =>
            Result := Create_Float (Value.Value.Float_Value);
      end case;

      return Result;
   end Clone;

   ----------------
   -- As_Boolean --
   ----------------

   function As_Boolean (Value : TOML_Value) return Boolean is
   begin
      return Value.Value.Boolean_Value;
   end As_Boolean;

   ----------------
   -- As_Integer --
   ----------------

   function As_Integer (Value : TOML_Value) return Any_Integer is
   begin
      return Value.Value.Integer_Value;
   end As_Integer;

   --------------
   -- As_Float --
   --------------

   function As_Float (Value : TOML_Value) return Any_Float is
   begin
      return Value.Value.Float_Value;
   end As_Float;

   ---------------
   -- As_String --
   ---------------

   function As_String (Value : TOML_Value) return String is
   begin
      return To_String (Value.As_Unbounded_String);
   end As_String;

   -------------------------
   -- As_Unbounded_String --
   -------------------------

   function As_Unbounded_String
     (Value : TOML_Value) return Ada.Strings.Unbounded.Unbounded_String is
   begin
      return Value.Value.String_Value;
   end As_Unbounded_String;

   ------------------------
   -- As_Offset_Datetime --
   ------------------------

   function As_Offset_Datetime (Value : TOML_Value) return Any_Offset_Datetime
   is
   begin
      return Value.Value.Offset_Datetime_Value;
   end As_Offset_Datetime;

   -----------------------
   -- As_Local_Datetime --
   -----------------------

   function As_Local_Datetime (Value : TOML_Value) return Any_Local_Datetime is
   begin
      return Value.Value.Local_Datetime_Value;
   end As_Local_Datetime;

   -------------------
   -- As_Local_Date --
   -------------------

   function As_Local_Date (Value : TOML_Value) return Any_Local_Date is
   begin
      return Value.Value.Local_Date_Value;
   end As_Local_Date;

   -------------------
   -- As_Local_Time --
   -------------------

   function As_Local_Time (Value : TOML_Value) return Any_Local_Time is
   begin
      return Value.Value.Local_Time_Value;
   end As_Local_Time;

   ---------
   -- Has --
   ---------

   function Has (Value : TOML_Value; Key : String) return Boolean is
   begin
      return Value.Has (To_Unbounded_String (Key));
   end Has;

   ---------
   -- Has --
   ---------

   function Has
     (Value : TOML_Value; Key : Unbounded_UTF8_String) return Boolean is
   begin
      return Value.Value.Map_Value.Contains (Key);
   end Has;

   ----------
   -- Keys --
   ----------

   function Keys (Value : TOML_Value) return Key_Array is
      use TOML_Maps;
      Map : TOML_Maps.Map renames Value.Value.Map_Value;
      I   : Positive := 1;
   begin
      return Result : Key_Array (1 .. Natural (Map.Length)) do
         for Position in Map.Iterate loop
            Result (I) := Key (Position);
            I := I + 1;
         end loop;
         Sort_Keys (Result);
      end return;
   end Keys;

   ---------
   -- Get --
   ---------

   function Get (Value : TOML_Value; Key : String) return TOML_Value is
   begin
      return Value.Get (To_Unbounded_String (Key));
   end Get;

   ---------
   -- Get --
   ---------

   function Get
     (Value : TOML_Value; Key : Unbounded_UTF8_String) return TOML_Value is
   begin
      return Value.Value.Map_Value.Element (Key);
   end Get;

   -----------------
   -- Get_Or_Null --
   -----------------

   function Get_Or_Null (Value : TOML_Value; Key : String) return TOML_Value
   is
   begin
      return Value.Get_Or_Null (To_Unbounded_String (Key));
   end Get_Or_Null;

   -----------------
   -- Get_Or_Null --
   -----------------

   function Get_Or_Null
     (Value : TOML_Value; Key : Unbounded_UTF8_String) return TOML_Value
   is
      use TOML_Maps;
      Position : constant Cursor := Value.Value.Map_Value.Find (Key);
   begin
      return (if Has_Element (Position)
              then Element (Position)
              else No_TOML_Value);
   end Get_Or_Null;

   ----------------------
   -- Iterate_On_Table --
   ----------------------

   function Iterate_On_Table (Value : TOML_Value) return Table_Entry_Array is
      Keys : constant Key_Array := Value.Keys;
   begin
      return Result : Table_Entry_Array (Keys'Range) do
         for I In Keys'Range loop
            Result (I) := (Keys (I), Value.Get (Keys (I)));
         end loop;
      end return;
   end Iterate_On_Table;

   ------------
   -- Length --
   ------------

   function Length (Value : TOML_Value) return Natural is
   begin
      return Natural (Value.Value.Array_Value.Length);
   end Length;

   ----------
   -- Item --
   ----------

   function Item (Value : TOML_Value; Index : Positive) return TOML_Value is
   begin
      return Value.Value.Array_Value.Element (Index);
   end Item;

   --------------------
   -- Create_Boolean --
   --------------------

   function Create_Boolean (Value : Boolean) return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind => TOML_Boolean, Ref_Count => 1, Boolean_Value => Value));
   end Create_Boolean;

   --------------------
   -- Create_Integer --
   --------------------

   function Create_Integer (Value : Any_Integer) return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind => TOML_Integer, Ref_Count => 1, Integer_Value => Value));
   end Create_Integer;

   ------------------
   -- Create_Float --
   ------------------

   function Create_Float (Value : Any_Float) return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind => TOML_Float, Ref_Count => 1, Float_Value => Value));
   end Create_Float;

   -------------------
   -- Create_String --
   -------------------

   function Create_String (Value : String) return TOML_Value is
   begin
      return Create_String (To_Unbounded_String (Value));
   end Create_String;

   -------------------
   -- Create_String --
   -------------------

   function Create_String (Value : Unbounded_UTF8_String) return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind         => TOML_String,
         Ref_Count    => 1,
         String_Value => Value));
   end Create_String;

   ----------------------------
   -- Create_Offset_Datetime --
   ----------------------------

   function Create_Offset_Datetime
     (Value : Any_Offset_Datetime) return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind                  => TOML_Offset_Datetime,
         Ref_Count             => 1,
         Offset_Datetime_Value => Value));
   end Create_Offset_Datetime;

   ---------------------------
   -- Create_Local_Datetime --
   ---------------------------

   function Create_Local_Datetime
     (Value : Any_Local_Datetime) return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind                 => TOML_Local_Datetime,
         Ref_Count            => 1,
         Local_Datetime_Value => Value));
   end Create_Local_Datetime;

   -----------------------
   -- Create_Local_Date --
   -----------------------

   function Create_Local_Date (Value : Any_Local_Date) return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind             => TOML_Local_Date,
         Ref_Count        => 1,
         Local_Date_Value => Value));
   end Create_Local_Date;

   -----------------------
   -- Create_Local_Time --
   -----------------------

   function Create_Local_Time (Value : Any_Local_Time) return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind             => TOML_Local_Time,
         Ref_Count        => 1,
         Local_Time_Value => Value));
   end Create_Local_Time;

   ------------------
   -- Create_Table --
   ------------------

   function Create_Table return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind                     => TOML_Table,
         Ref_Count                => 1,
         Map_Value                => <>,
         Table_Implicitly_Created => False));
   end Create_Table;

   ---------
   -- Set --
   ---------

   procedure Set (Value : TOML_Value; Key : String; Entry_Value : TOML_Value)
   is
   begin
      Value.Set (To_Unbounded_String (Key), Entry_Value);
   end Set;

   ---------
   -- Set --
   ---------

   procedure Set
     (Value       : TOML_Value;
      Key         : Unbounded_UTF8_String;
      Entry_Value : TOML_Value)
   is
   begin
      Value.Value.Map_Value.Include (Key, Entry_Value);
   end Set;

   -----------------
   -- Set_Default --
   -----------------

   procedure Set_Default
     (Value : TOML_Value; Key : String; Entry_Value : TOML_Value)
   is
   begin
      Value.Set_Default (To_Unbounded_String (Key), Entry_Value);
   end Set_Default;

   -----------------
   -- Set_Default --
   -----------------

   procedure Set_Default
     (Value       : TOML_Value;
      Key         : Unbounded_UTF8_String;
      Entry_Value : TOML_Value)
   is
      use TOML_Maps;
      Dummy_Position : Cursor;
      Dummy_Inserted : Boolean;
   begin
      Value.Value.Map_Value.Insert
        (Key, Entry_Value, Dummy_Position, Dummy_Inserted);
   end Set_Default;

   -----------
   -- Unset --
   -----------

   procedure Unset (Value : TOML_Value; Key : String) is
   begin
      Value.Unset (To_Unbounded_String (Key));
   end Unset;

   -----------
   -- Unset --
   -----------

   procedure Unset (Value : TOML_Value; Key : Unbounded_UTF8_String) is
   begin
      Value.Value.Map_Value.Delete (Key);
   end Unset;

   -----------
   -- Merge --
   -----------

   function Merge (L, R : TOML_Value) return TOML_Value is
      function Merge_Entries
        (Key              : Unbounded_UTF8_String;
         Dummy_L, Dummy_R : TOML_Value) return TOML_Value
      is (raise Constraint_Error with "duplicate key: " & To_String (Key));
   begin
      return Merge (L, R, Merge_Entries'Access);
   end Merge;

   -----------
   -- Merge --
   -----------

   function Merge
     (L, R          : TOML_Value;
      Merge_Entries : not null access function
        (Key : Unbounded_UTF8_String; L, R : TOML_Value) return TOML_Value)
      return TOML_Value
   is
      Table : constant TOML_Value := Create_Table;
   begin
      for Key of L.Keys loop
         Table.Set (Key, L.Get (Key));
      end loop;

      for Key of R.Keys loop
         declare
            Value : TOML_Value := R.Get (Key);
         begin
            if Table.Has (Key) then
               Value := Merge_Entries (Key, Table.Get (Key), Value);
            end if;
            Table.Set (Key, Value);
         end;
      end loop;

      return Table;
   end Merge;

   ------------------
   -- Create_Array --
   ------------------

   function Create_Array return TOML_Value is
   begin
      return Create_Value (new TOML_Value_Record'
        (Kind                     => TOML_Array,
         Ref_Count                => 1,
         Array_Value              => <>,
         Array_Implicitly_Created => False));
   end Create_Array;

   ---------
   -- Set --
   ---------

   procedure Set (Value : TOML_Value; Index : Positive; Item : TOML_Value) is
   begin
      Value.Value.Array_Value (Index) := Item;
   end Set;

   ------------
   -- Append --
   ------------

   procedure Append (Value, Item : TOML_Value) is
   begin
      Value.Value.Array_Value.Append (Item);
   end Append;

   -------------------
   -- Insert_Before --
   -------------------

   procedure Insert_Before
     (Value : TOML_Value; Index : Positive; Item : TOML_Value)
   is
   begin
      Value.Value.Array_Value.Insert (Index, Item);
   end Insert_Before;

   -----------------
   -- Load_String --
   -----------------

   function Load_String (Content : String) return Read_Result is
      type Input_Stream is record
         Next_Character : Positive;
         --  Index of the next character in Content that Get must return
      end record;

      procedure Get
        (Stream : in out Input_Stream;
         EOF    : out Boolean;
         Byte   : out Character);
      --  Callback for Parse_String

      ---------
      -- Get --
      ---------

      procedure Get
        (Stream : in out Input_Stream;
         EOF    : out Boolean;
         Byte   : out Character) is
      begin
         if Stream.Next_Character > Content'Length then
            EOF := True;
         else
            EOF := False;
            Byte := Content (Stream.Next_Character);
            Stream.Next_Character := Stream.Next_Character + 1;
         end if;
      end Get;

      function Parse_String is new TOML.Generic_Parse (Input_Stream, Get);

      Stream : Input_Stream := (Next_Character => Content'First);
   begin
      return Parse_String (Stream);
   end Load_String;

   --------------------
   -- Dump_As_String --
   --------------------

   function Dump_As_String (Value : TOML_Value) return String is
   begin
      return To_String (Dump_As_Unbounded (Value));
   end Dump_As_String;

   -----------------------
   -- Dump_As_Unbounded --
   -----------------------

   function Dump_As_Unbounded
     (Value : TOML_Value) return Unbounded_UTF8_String is
   begin
      return Result : Unbounded_UTF8_String do
         Dump_To_String (Result, Value);
      end return;
   end Dump_As_Unbounded;

   ------------------
   -- Format_Error --
   ------------------

   function Format_Error (Result : Read_Result) return String is
      Formatted : Unbounded_UTF8_String;
   begin
      if Result.Location.Line /= 0 then
         declare
            L : constant String := Result.Location.Line'Image;
            C : constant String := Result.Location.Column'Image;
         begin
            Append (Formatted, L (L'First + 1 .. L'Last));
            Append (Formatted, ":");
            Append (Formatted, C (C'First + 1 .. C'Last));
            Append (Formatted, ": ");
         end;
      end if;

      Append (Formatted, Result.Message);
      return To_String (Formatted);
   end Format_Error;

   ------------
   -- Adjust --
   ------------

   overriding procedure Adjust (Self : in out TOML_Value) is
   begin
      if Self.Value = null then
         return;
      end if;

      Self.Value.Ref_Count := Self.Value.Ref_Count + 1;
   end Adjust;

   --------------
   -- Finalize --
   --------------

   overriding procedure Finalize (Self : in out TOML_Value) is
   begin
      if Self.Value = null then
         return;
      end if;

      declare
         V : TOML_Value_Record renames Self.Value.all;
      begin
         --  Decrement the ref-count. If no-one references V anymore,
         --  deallocate it.

         V.Ref_Count := V.Ref_Count - 1;
         if V.Ref_Count > 0 then
            return;
         end if;
      end;

      Free (Self.Value);
   end Finalize;

   ------------------------
   -- Implicitly_Created --
   ------------------------

   function Implicitly_Created (Self : TOML_Value'Class) return Boolean is
   begin
      if Self.Kind = TOML_Table then
         return Self.Value.Table_Implicitly_Created;
      else
         return Self.Value.Array_Implicitly_Created;
      end if;
   end Implicitly_Created;

   ----------------------------
   -- Set_Implicitly_Created --
   ----------------------------

   procedure Set_Implicitly_Created (Self : TOML_Value'Class) is
   begin
      if Self.Kind = TOML_Table then
         Self.Value.Table_Implicitly_Created := True;
      else
         Self.Value.Array_Implicitly_Created := True;
      end if;
   end Set_Implicitly_Created;

   ----------------------------
   -- Set_Explicitly_Created --
   ----------------------------

   procedure Set_Explicitly_Created (Self : TOML_Value'Class) is
   begin
      if Self.Kind = TOML_Table then
         Self.Value.Table_Implicitly_Created := False;
      else
         Self.Value.Array_Implicitly_Created := False;
      end if;
   end Set_Explicitly_Created;

end TOML;