"""Business logic: compute worked hours and expected hours per day/week."""
from datetime import datetime, timedelta

DEFAULT_PLAGES = {
    "matin_debut": "09:00",        # présence obligatoire à partir de cette heure le matin
    "matin_fin": "12:00",          # présence obligatoire jusqu'à cette heure le matin
    "aprem_debut": "14:00",        # présence obligatoire à partir de cette heure l'après-midi
    "aprem_fin": "17:00",          # présence obligatoire jusqu'à cette heure l'après-midi (plancher de sortie)
    "pause_dejeuner_fin": "13:30",  # reprise par défaut projetée tant que l'entrée aprem n'est pas saisie
}


def hhmm_to_minutes(val: str | None) -> int:
    if not val:
        return 0
    h, m = val.split(":")
    return int(h) * 60 + int(m)


def minutes_to_hhmm(minutes: int) -> str:
    sign = "-" if minutes < 0 else ""
    minutes = abs(minutes)
    return f"{sign}{minutes // 60}h{minutes % 60:02d}"


def heures_travaillees(p: dict) -> int:
    """Return worked minutes for a pointage row.

    If a half-day has started but has no exit time yet, count elapsed time up to now
    (today only — past dates with missing exits are treated as 0).
    """
    today = datetime.today().strftime("%Y-%m-%d")
    now_min = datetime.today().hour * 60 + datetime.today().minute

    matin = 0
    if p["matin_entree"] and p["matin_sortie"]:
        matin = max(0, hhmm_to_minutes(p["matin_sortie"]) - hhmm_to_minutes(p["matin_entree"]))
    elif p["matin_entree"] and p.get("date") == today:
        matin = max(0, now_min - hhmm_to_minutes(p["matin_entree"]))

    aprem = 0
    if p["aprem_entree"] and p["aprem_sortie"]:
        aprem = max(0, hhmm_to_minutes(p["aprem_sortie"]) - hhmm_to_minutes(p["aprem_entree"]))
    elif p["aprem_entree"] and p.get("date") == today:
        aprem = max(0, now_min - hhmm_to_minutes(p["aprem_entree"]))

    return matin + aprem


def heures_dues(date_str: str, conges: list[dict], heures_jour_min: int) -> int:
    """Return expected minutes for a date, accounting for vacations."""
    d = datetime.strptime(date_str, "%Y-%m-%d").date()
    # Weekend = no hours due
    if d.weekday() >= 5:
        return 0

    conges_date = {c["type"] for c in conges if c["date"] == date_str}

    if "jour" in conges_date:
        return 0
    if "matin" in conges_date and "aprem" in conges_date:
        return 0

    half = heures_jour_min // 2
    if "matin" in conges_date or "aprem" in conges_date:
        return half

    return heures_jour_min


def compute_week(pointages: list[dict], conges: list[dict], heures_jour_min: int, plages: dict | None = None) -> dict:
    """Compute totals for a list of pointages (one week)."""
    plages = {**DEFAULT_PLAGES, **(plages or {})}
    matin_debut_min = hhmm_to_minutes(plages["matin_debut"])
    matin_fin_min = hhmm_to_minutes(plages["matin_fin"])
    aprem_fin_min = hhmm_to_minutes(plages["aprem_fin"])
    pause_dejeuner_fin_min = hhmm_to_minutes(plages["pause_dejeuner_fin"])

    total_travaille = 0
    total_du = 0
    jours = []

    for p in pointages:
        travaille = heures_travaillees(p)
        du = heures_dues(p["date"], conges, heures_jour_min)
        delta = travaille - du
        total_travaille += travaille
        total_du += du
        jours.append({
            **p,
            "travaille_min": travaille,
            "du_min": du,
            "delta_min": delta,
            "travaille": minutes_to_hhmm(travaille),
            "du": minutes_to_hhmm(du),
            "delta": minutes_to_hhmm(delta),
            "conge": {c["type"] for c in conges if c["date"] == p["date"]},
        })

    # Mark each day as complete (all non-congé slots filled, or day is a congé/weekend)
    for jour in jours:
        cg = jour["conge"]
        matin_done = bool(jour.get("matin_entree") and jour.get("matin_sortie")) or "matin" in cg or "jour" in cg
        aprem_done = bool(jour.get("aprem_entree") and jour.get("aprem_sortie")) or "aprem" in cg or "jour" in cg
        jour["is_complete"] = (jour["du_min"] == 0) or (matin_done and aprem_done)

    # Cumulative weekly delta — accumulated for all days, but visible only when chain is unbroken
    cumul = 0
    cumul_chain_ok = True
    for jour in jours:
        cumul += jour["delta_min"]
        jour["delta_cumul_min"] = cumul
        jour["delta_cumul"] = minutes_to_hhmm(abs(cumul))
        # Chain breaks on the first incomplete workday — subsequent days don't show cumul
        if not jour["is_complete"] and jour["du_min"] > 0:
            cumul_chain_ok = False
        jour["cumul_visible"] = jour["is_complete"] and cumul_chain_ok

    # Préconisations : répartit le manque restant à parts égales sur les demi-journées
    # restantes (au lieu de tout reporter sur la fin de journée courante), pour permettre
    # un rattrapage progressif et confortable jusqu'à la fin de semaine.
    for jour in jours:
        jour["cible_matin"] = None
        jour["cible_aprem"] = None

    today = datetime.today().strftime("%Y-%m-%d")
    restant = total_du - total_travaille
    slots = []  # (jour, "matin"|"aprem", nominal_min)
    for jour in jours:
        if jour["date"] < today:
            continue  # jour passé : impossible d'y rattraper quoi que ce soit
        cg = jour["conge"]
        du = jour["du_min"]
        if du == 0:
            continue
        matin_nominal = 0 if "matin" in cg else (du if "aprem" in cg else du // 2)
        aprem_nominal = 0 if "aprem" in cg else (du if "matin" in cg else du - du // 2)
        matin_done = bool(jour.get("matin_entree") and jour.get("matin_sortie")) or "matin" in cg or "jour" in cg
        aprem_done = bool(jour.get("aprem_entree") and jour.get("aprem_sortie")) or "aprem" in cg or "jour" in cg
        if not matin_done:
            slots.append((jour, "matin", matin_nominal))
        if not aprem_done:
            slots.append((jour, "aprem", aprem_nominal))

    extra_total = max(0, restant - sum(s[2] for s in slots)) if slots else 0
    slots_restants = len(slots)

    if slots_restants:
        base, remainder = divmod(extra_total, slots_restants)
        for i, (jour, half, nominal) in enumerate(slots):
            adj = base + (1 if i < remainder else 0)
            duree_cible = nominal + adj
            if adj <= 0:
                continue  # rythme normal suffit pour cette demi-journée, rien à signaler
            if half == "matin":
                debut_min = hhmm_to_minutes(jour["matin_entree"]) if jour.get("matin_entree") else matin_debut_min
                sortie_min = max(debut_min + duree_cible, matin_fin_min)
            else:
                debut_min = hhmm_to_minutes(jour["aprem_entree"]) if jour.get("aprem_entree") else pause_dejeuner_fin_min
                sortie_min = max(debut_min + duree_cible, aprem_fin_min)
            if sortie_min > 23 * 60 + 59:
                continue  # rattrapage impossible en une seule demi-journée
            cible = f"{sortie_min // 60:02d}:{sortie_min % 60:02d}"
            if half == "matin":
                jour["cible_matin"] = cible
            else:
                jour["cible_aprem"] = cible

    reste_min = max(0, restant)

    return {
        "jours": jours,
        "total_travaille": minutes_to_hhmm(total_travaille),
        "total_du": minutes_to_hhmm(total_du),
        "solde": minutes_to_hhmm(total_travaille - total_du),
        "solde_min": total_travaille - total_du,
        "reste_min": reste_min,
        "reste": minutes_to_hhmm(reste_min),
        "extra_min": extra_total,
        "extra": minutes_to_hhmm(extra_total),
        "slots_restants": slots_restants,
        "moyenne_extra_min": (extra_total // slots_restants) if slots_restants else 0,
        "moyenne_extra": minutes_to_hhmm((extra_total // slots_restants) if slots_restants else 0),
    }