sync: implement hint dependency on flags

libfic/hint.go

@@ -1,6 +1,8 @@
 package fic
 
 import (
+	"errors"
+	"fmt"
 	"path"
 	"strings"
 )
@@ -105,7 +107,9 @@ func (h EHint) Delete() (int64, error) {
 
 // WipeHints deletes (only in the database, not on disk) hints coming with the challenge.
 func (e Exercice) WipeHints() (int64, error) {
-	if res, err := DBExec("DELETE FROM exercice_hints WHERE id_exercice = ?", e.Id); err != nil {
+	if _, err := DBExec("DELETE FROM exercice_hints_deps WHERE id_hint IN (SELECT id_hint FROM exercice_hints WHERE id_exercice = ?)", e.Id); err != nil {
+		return 0, err
+	} else if res, err := DBExec("DELETE FROM exercice_hints WHERE id_exercice = ?", e.Id); err != nil {
 		return 0, err
 	} else if nb, err := res.RowsAffected(); err != nil {
 		return 0, err
@@ -114,6 +118,40 @@ func (e Exercice) WipeHints() (int64, error) {
 	}
 }
 
+// AddDepend insert a new dependency to a given flag.
+func (h EHint) AddDepend(f Flag) (err error) {
+	if d, ok := f.(FlagKey); ok {
+		_, err = DBExec("INSERT INTO exercice_hints_deps (id_hint, id_flag_dep) VALUES (?, ?)", h.Id, d.Id)
+	} else {
+		err = errors.New(fmt.Sprintf("Dependancy type for key (%T) not implemented for this flag.", f))
+	}
+	return
+}
+
+// GetDepends retrieve the flag's dependency list.
+func (h EHint) GetDepends() ([]Flag, error) {
+	var deps = make([]Flag, 0)
+
+	if rows, err := DBQuery("SELECT id_flag_dep FROM exercice_hints_deps WHERE id_hint = ?", h.Id); err != nil {
+		return nil, err
+	} else {
+		defer rows.Close()
+
+		for rows.Next() {
+			var d int64
+			if err := rows.Scan(&d); err != nil {
+				return nil, err
+			}
+			deps = append(deps, FlagKey{Id: d, IdExercice: h.IdExercice})
+		}
+		if err := rows.Err(); err != nil {
+			return nil, err
+		}
+	}
+
+	return deps, nil
+}
+
 // GetExercice returns the parent Exercice where this hint can be found.
 func (h EHint) GetExercice() (Exercice, error) {
 	var eid int64