"""database.py — Persistent storage for groups, students, attendance"""
import json, uuid, os
from pathlib import Path
from datetime import datetime

DATA_DIR      = Path("data")
EMBED_FILE    = DATA_DIR / "embeddings.json"
GROUPS_FILE   = DATA_DIR / "groups.json"
ATT_DIR       = DATA_DIR / "attendance"

def _init():
    DATA_DIR.mkdir(exist_ok=True)
    ATT_DIR.mkdir(exist_ok=True)

# ── Groups ────────────────────────────────────────────────────
def load_groups():
    _init()
    if not GROUPS_FILE.exists(): return {}
    try: return json.loads(GROUPS_FILE.read_text())
    except: return {}

def save_groups(g):
    _init(); GROUPS_FILE.write_text(json.dumps(g, indent=2))

def create_group(name, color="#a855f7"):
    g = load_groups()
    if any(v["name"].lower()==name.lower() for v in g.values()):
        return None, "Group already exists"
    gid = str(uuid.uuid4())[:8]
    g[gid] = {"name": name, "color": color, "created": datetime.now().isoformat()}
    save_groups(g); return gid, "OK"

def delete_group(gid):
    g = load_groups()
    if gid not in g: return False
    del g[gid]; save_groups(g)
    # remove students
    e = load_embeddings()
    for sid in [k for k,v in e.items() if v.get("group_id")==gid]:
        del e[sid]
    save_embeddings(e); return True

# ── Students / Embeddings ─────────────────────────────────────
def load_embeddings():
    _init()
    if not EMBED_FILE.exists(): return {}
    try: return json.loads(EMBED_FILE.read_text())
    except: return {}

def save_embeddings(e):
    _init(); EMBED_FILE.write_text(json.dumps(e, indent=2))

def add_student(name, group_id, fingerprint):
    """
    fingerprint = list of vectors (one per captured pose/angle) OR
                  a single plain vector (legacy) OR
                  { 'insight': list-of-vectors|vector|None, 'facenet':..., 'geo':... }
    Each pose is stored separately so matching can pick the best-fitting angle
    instead of averaging poses into one blurry vector.
    One registration per name per group.
    """
    e = load_embeddings()
    if any(v["group_id"]==group_id and v["name"].lower()==name.lower() for v in e.values()):
        return None, f"'{name}' already registered in this group"
    sid = str(uuid.uuid4())[:12]

    def _as_pose_list(v):
        if v is None:
            return None
        # list of vectors (each vector is itself a list of floats)
        if isinstance(v, list) and v and isinstance(v[0], list):
            return v
        # single flat vector -> wrap as a 1-pose list
        if isinstance(v, list):
            return [v]
        return None

    if isinstance(fingerprint, dict):
        fp_dict = fingerprint
        insight = _as_pose_list(fp_dict.get("insight"))
        facenet = _as_pose_list(fp_dict.get("facenet"))
        geo     = _as_pose_list(fp_dict.get("geo"))
    else:
        insight = _as_pose_list(fingerprint)
        facenet = None
        geo     = None

    e[sid] = {
        "name":       name,
        "group_id":   group_id,
        "insight":    insight,   # list of pose vectors, e.g. [front, left, right]
        "facenet":    facenet,
        "geo":        geo,
        "registered": datetime.now().isoformat(),
    }
    save_embeddings(e); return sid, "OK"

def delete_student(sid):
    e = load_embeddings()
    if sid not in e: return False
    del e[sid]; save_embeddings(e); return True

def get_students_in_group(gid):
    e = load_embeddings()
    return [{"id":k,"name":v["name"],"registered":v.get("registered","")}
            for k,v in e.items() if v.get("group_id")==gid]

def get_group_embeddings(gid):
    e = load_embeddings()
    return {k:v for k,v in e.items() if v.get("group_id")==gid}

def get_all_embeddings():
    return load_embeddings()

# ── Attendance ────────────────────────────────────────────────
def today():
    return datetime.now().strftime("%Y-%m-%d")

def _att_file(d=None):
    _init(); return ATT_DIR / f"{d or today()}.json"

def load_att():
    f = _att_file()
    if not f.exists(): return {}
    try: return json.loads(f.read_text())
    except: return {}

def save_att(a):
    _att_file().write_text(json.dumps(a, indent=2))

def mark_present(sid, name, gid):
    a   = load_att()
    now = datetime.now()
    if sid in a:
        last = datetime.fromisoformat(a[sid]["time"])
        if (now-last).total_seconds() < 600: return False
    a[sid] = {"name":name,"group_id":gid,"time":now.isoformat(),"status":"present"}
    save_att(a); return True

def get_summary(gid=None):
    a   = load_att()
    e   = load_embeddings()
    all_s = {k:v for k,v in e.items() if gid is None or v.get("group_id")==gid}
    present = [{"id":k,"name":v["name"],"group_id":v.get("group_id",""),"time":a[k]["time"]}
               for k,v in all_s.items() if k in a]
    absent  = [{"id":k,"name":v["name"],"group_id":v.get("group_id","")}
               for k,v in all_s.items() if k not in a]
    return {"present":present,"absent":absent}

def reset_att():
    f = _att_file()
    if f.exists(): f.unlink()

reset_today = reset_att  # alias used in app.py

def export_csv(gid=None):
    s = get_summary(gid); g = load_groups()
    gn = lambda id: g.get(id,{}).get("name",id)
    rows = ["Name,Group,Status,Time"]
    for x in s["present"]:
        rows.append(f"{x['name']},{gn(x['group_id'])},Present,{x['time'][:19].replace('T',' ')}")
    for x in s["absent"]:
        rows.append(f"{x['name']},{gn(x['group_id'])},Absent,")
    return "\n".join(rows)