extends Node
## Chargement et deroulement des exercices a partir des donnees JSON validees.
## Valide chaque fichier au chargement avec le meme validateur que
## `make validate-data` (DataLoader/SchemaValidator, scripts/data/) : un
## fichier invalide est ignore (avec une erreur journalisee), jamais charge
## tel quel. Le tirage au sort d'un exercice est delegue a ExercisePicker,
## pur, avec un generateur aleatoire possede ici (voir CLAUDE.md : le hasard
## est injecte dans la logique pure, pas lu directement par elle).

var _rules: Dictionary = {}
var _exercises_by_rule_and_type: Dictionary = {}
var _dictations_by_rule: Dictionary = {}
var _reward_items: Array[Dictionary] = []
var _regions: Dictionary = {}
var _region_order: Array[String] = []
var _missions: Dictionary = {}
var _mission_order: Array[String] = []
var _rng := RandomNumberGenerator.new()


func _ready() -> void:
    _rng.randomize()
    _load_rules()
    _load_regions()
    _load_exercises()
    _load_dictations()
    _load_missions()
    _load_rewards()


func get_rule(rule_id: String) -> Dictionary:
    return _rules.get(rule_id, {})


func get_missions() -> Array[Dictionary]:
    var missions: Array[Dictionary] = []
    for mission_id in _mission_order:
        missions.append(_missions[mission_id])
    return missions


## Missions dont la regle appartient au niveau scolaire demande (le niveau
## d'une mission est celui de sa regle, pas un champ de plus a tenir a jour).
func get_missions_for_level(level: String) -> Array[Dictionary]:
    var missions: Array[Dictionary] = []
    for mission in get_missions():
        if get_rule(mission["rule_id"]).get("level", "") == level:
            missions.append(mission)
    return missions


## « Tableaux » (regions de la carte) du niveau, dans l'ordre d'affichage :
## chacun est un fichier de data/curriculum/ (titre, decor, regles).
func get_regions_for_level(level: String) -> Array[Dictionary]:
    var regions: Array[Dictionary] = []
    for region_id in _region_order:
        if _regions[region_id]["level"] == level:
            regions.append(_regions[region_id])
    return regions


func get_region(region_id: String) -> Dictionary:
    return _regions.get(region_id, {})


## Tableau auquel appartient une regle ("" si aucun).
func region_id_for_rule(rule_id: String) -> String:
    for region_id in _region_order:
        if (_regions[region_id]["rule_ids"] as Array).has(rule_id):
            return region_id
    return ""


## Missions d'un tableau : celles dont la regle figure dans ce tableau.
func get_missions_for_region(region_id: String) -> Array[Dictionary]:
    var missions: Array[Dictionary] = []
    var rule_ids: Array = _regions.get(region_id, {}).get("rule_ids", [])
    for mission in get_missions():
        if rule_ids.has(mission["rule_id"]):
            missions.append(mission)
    return missions


## Decor (BackdropKinds) du tableau d'une regle ; a defaut, celui du niveau.
func backdrop_for_rule(rule_id: String) -> String:
    var region := get_region(region_id_for_rule(rule_id))
    var kind: String = region.get("backdrop", "")
    if BackdropKinds.is_valid(kind):
        return kind
    return "marsh" if get_rule(rule_id).get("level", "") == "CE2" else BackdropKinds.FALLBACK


## Catalogue des objets de la collection, du plus facile au plus difficile
## a obtenir (ordre stable : seuil puis identifiant).
func get_reward_items() -> Array[Dictionary]:
    return _reward_items


func get_mission(mission_id: String) -> Dictionary:
    return _missions.get(mission_id, {})


## Tire le prochain exercice (ou dictee) pour une mission, au plus proche de
## `difficulty`, sans redonner `exclude_id`. Dictionnaire vide si la mission
## n'a aucun contenu disponible.
func pick_exercise_for_mission(
    mission: Dictionary, exclude_id: String, difficulty: int
) -> Dictionary:
    var rule_id: String = mission["rule_id"]
    var exercise_type: String = mission["exercise_type"]
    var candidates: Array[Dictionary] = _candidates_for(rule_id, exercise_type)
    var filtered := _filter_by_difficulty(candidates, difficulty)
    var picked: Variant = ExercisePicker.pick(filtered, exclude_id, _rng)
    return picked if picked != null else {}


## Comme pick_exercise_for_mission, mais ne redonne jamais un exercice deja vu
## pendant la mission tant qu'il en reste un autre (un enfant ne doit pas voir
## deux fois la meme phrase dans une meme mission).
func pick_unseen_exercise_for_mission(
    mission: Dictionary, seen_ids: Array[String], difficulty: int
) -> Dictionary:
    var candidates: Array[Dictionary] = _candidates_for(
        mission["rule_id"], mission["exercise_type"]
    )
    var picked: Variant = ExercisePicker.pick_unseen(
        _filter_by_difficulty(candidates, difficulty), candidates, seen_ids, _rng
    )
    return picked if picked != null else {}


## Ne garde que les candidats a la difficulte demandee ; si aucun ne la
## propose, retombe sur l'ensemble des candidats plutot que de n'en donner
## aucun (le contenu disponible est encore limite, voir docs/specs/decisions.md).
func _filter_by_difficulty(candidates: Array[Dictionary], difficulty: int) -> Array[Dictionary]:
    var exact: Array[Dictionary] = []
    for candidate in candidates:
        if int(candidate.get("difficulty", difficulty)) == difficulty:
            exact.append(candidate)
    return exact if not exact.is_empty() else candidates


func _candidates_for(rule_id: String, exercise_type: String) -> Array[Dictionary]:
    if exercise_type == "dictation":
        return _dictations_by_rule.get(rule_id, [] as Array[Dictionary])
    var by_type: Dictionary = _exercises_by_rule_and_type.get(rule_id, {})
    return by_type.get(exercise_type, [] as Array[Dictionary])


func _load_rules() -> void:
    for path in DataLoader.find_json_files("res://data/rules"):
        var errors := DataLoader.validate_file(path, "rule")
        if not errors.is_empty():
            push_error("Regle ignoree (%s) : %s" % [path, errors])
            continue
        var rule: Dictionary = DataLoader.read_json(path)
        _rules[rule["rule_id"]] = rule


func _load_regions() -> void:
    var loaded: Array[Dictionary] = []
    for path in DataLoader.find_json_files("res://data/curriculum"):
        var errors := DataLoader.validate_file(path, "curriculum")
        if not errors.is_empty():
            push_error("Tableau ignore (%s) : %s" % [path, errors])
            continue
        loaded.append(DataLoader.read_json(path))
    # Ordre : niveau, puis numero de tableau, puis identifiant (stable).
    loaded.sort_custom(
        func(a: Dictionary, b: Dictionary) -> bool:
            var rank_a := SchoolLevels.rank(a["level"])
            var rank_b := SchoolLevels.rank(b["level"])
            if rank_a != rank_b:
                return rank_a < rank_b
            var order_a := int(a.get("order", 1))
            var order_b := int(b.get("order", 1))
            if order_a != order_b:
                return order_a < order_b
            return a["region_id"] < b["region_id"]
    )
    for region in loaded:
        _regions[region["region_id"]] = region
        _region_order.append(region["region_id"])


func _load_exercises() -> void:
    for path in DataLoader.find_json_files("res://data/exercises"):
        var raw: Variant = DataLoader.read_json(path)
        if typeof(raw) != TYPE_DICTIONARY or not raw.has("type"):
            push_error("Exercice ignore (%s) : type manquant ou JSON invalide" % path)
            continue
        var exercise: Dictionary = raw
        var exercise_type: String = exercise["type"]
        var schema_name := DataLoader.exercise_schema_name_for_type(exercise_type)
        if schema_name.is_empty():
            push_error("Exercice ignore (%s) : type inconnu '%s'" % [path, exercise_type])
            continue
        var errors := SchemaValidator.validate(exercise, DataLoader.load_schema(schema_name))
        if not errors.is_empty():
            push_error("Exercice ignore (%s) : %s" % [path, errors])
            continue

        var rule_id: String = exercise["rule_id"]
        if not _exercises_by_rule_and_type.has(rule_id):
            _exercises_by_rule_and_type[rule_id] = {}
        var by_type: Dictionary = _exercises_by_rule_and_type[rule_id]
        if not by_type.has(exercise_type):
            by_type[exercise_type] = [] as Array[Dictionary]
        (by_type[exercise_type] as Array[Dictionary]).append(exercise)


func _load_dictations() -> void:
    for path in DataLoader.find_json_files("res://data/dictations"):
        var errors := DataLoader.validate_file(path, "dictation")
        if not errors.is_empty():
            push_error("Dictee ignoree (%s) : %s" % [path, errors])
            continue
        var dictation: Dictionary = DataLoader.read_json(path)
        for rule_id: String in dictation["rule_ids"]:
            if not _dictations_by_rule.has(rule_id):
                _dictations_by_rule[rule_id] = [] as Array[Dictionary]
            (_dictations_by_rule[rule_id] as Array[Dictionary]).append(dictation)


func _load_missions() -> void:
    var mission_ids: Array[String] = []
    for path in DataLoader.find_json_files("res://data/missions"):
        var errors := DataLoader.validate_file(path, "mission")
        if not errors.is_empty():
            push_error("Mission ignoree (%s) : %s" % [path, errors])
            continue
        var mission: Dictionary = DataLoader.read_json(path)
        _missions[mission["mission_id"]] = mission
        mission_ids.append(mission["mission_id"])
    mission_ids.sort()
    _mission_order = mission_ids


func _load_rewards() -> void:
    for path in DataLoader.find_json_files("res://data/rewards"):
        var errors := DataLoader.validate_file(path, "reward_item")
        if not errors.is_empty():
            push_error("Objet de collection ignore (%s) : %s" % [path, errors])
            continue
        var item: Dictionary = DataLoader.read_json(path)
        _reward_items.append(item)
    _reward_items.sort_custom(
        func(a: Dictionary, b: Dictionary) -> bool:
            var count_a: int = a["unlock"]["count"]
            var count_b: int = b["unlock"]["count"]
            if count_a != count_b:
                return count_a < count_b
            return String(a["item_id"]) < String(b["item_id"])
    )