class_name ProgressUpdates
extends RefCounted
## Fonctions pures qui appliquent une tentative d'exercice ou un debut de
## seance a une sauvegarde (dictionnaire conforme a save.schema.json), en
## s'appuyant sur ReviewScheduler et DifficultyManager (scripts/pedagogy/).
## ProgressManager (autoload) est seul responsable d'appeler ces fonctions et
## de persister le resultat via SaveManager ; l'ecriture sur disque reste
## groupee en fin de mission (docs/specs/decisions.md, point 7).


## attempt : {"skill": String, "success": bool, "hint_used": bool,
## "exercise_type": String}.
static func record_attempt(save_data: Dictionary, attempt: Dictionary) -> Dictionary:
    var updated: Dictionary = save_data.duplicate(true)
    var skills: Dictionary = updated["skills"]
    var skill_id: String = attempt["skill"]
    var skill_state: Dictionary = (
        skills[skill_id] if skills.has(skill_id) else ReviewScheduler.initial_state()
    )
    var current_session: int = updated["session_count"]
    skills[skill_id] = ReviewScheduler.record_attempt(skill_state, attempt, current_session)
    updated["skills"] = skills
    return updated


## A appeler une fois en debut de seance, avant toute tentative : incremente
## session_count et bascule en "a_reviser" les competences "acquise" dont le
## delai de revision est depasse sans nouvelle pratique.
static func start_session(save_data: Dictionary) -> Dictionary:
    var updated: Dictionary = save_data.duplicate(true)
    updated["session_count"] = int(updated["session_count"]) + 1
    var current_session: int = updated["session_count"]

    var skills: Dictionary = updated["skills"]
    var updated_skills: Dictionary = {}
    for skill_id: String in skills:
        updated_skills[skill_id] = ReviewScheduler.mark_overdue_as_review(
            skills[skill_id], current_session
        )
    updated["skills"] = updated_skills
    return updated


static func next_difficulty_for_skill(
    save_data: Dictionary, skill_id: String, current_difficulty: int
) -> int:
    var skills: Dictionary = save_data["skills"]
    if not skills.has(skill_id):
        return current_difficulty
    # Relu depuis le disque (JSON), le tableau est un Array non type : on le
    # recopie dans un Array[bool] plutot que de l'affecter directement.
    var recent: Array[bool] = []
    for result: Variant in skills[skill_id]["recent_results"]:
        recent.append(bool(result))
    return DifficultyManager.next_difficulty(current_difficulty, recent)


static func unlock_region(save_data: Dictionary, region_id: String) -> Dictionary:
    var updated: Dictionary = save_data.duplicate(true)
    var regions: Array = updated["unlocked_regions"]
    if not regions.has(region_id):
        regions.append(region_id)
    updated["unlocked_regions"] = regions
    return updated


## Enregistre le resultat d'une mission terminee. Le meilleur score est
## conserve ; seules les etoiles gagnees en plus du meilleur score precedent
## s'ajoutent au total, donc rejouer une mission ne gonfle pas le total.
static func record_mission_result(
    save_data: Dictionary, mission_id: String, stars: int
) -> Dictionary:
    var updated: Dictionary = save_data.duplicate(true)
    var results: Dictionary = updated["mission_results"]
    var previous: Dictionary = results.get(mission_id, {})
    var previous_best: int = int(previous.get("best_stars", 0))
    var new_best: int = maxi(previous_best, stars)

    results[mission_id] = {
        "best_stars": new_best,
        "last_stars": stars,
        "completions": int(previous.get("completions", 0)) + 1,
    }
    updated["mission_results"] = results

    var rewards: Dictionary = updated["rewards"].duplicate(true)
    rewards["stars"] = int(rewards["stars"]) + (new_best - previous_best)
    updated["rewards"] = rewards
    return updated


static func grant_items(save_data: Dictionary, item_ids: Array[String]) -> Dictionary:
    var updated: Dictionary = save_data.duplicate(true)
    var rewards: Dictionary = updated["rewards"].duplicate(true)
    var items: Array = rewards["items"]
    for item_id in item_ids:
        if not items.has(item_id):
            items.append(item_id)
    rewards["items"] = items
    updated["rewards"] = rewards
    return updated