from datetime import datetime
from pathlib import Path
from uuid import uuid4

from fastapi import APIRouter, Depends, File, Form, Request, UploadFile
from fastapi.responses import HTMLResponse, RedirectResponse
from fastapi.templating import Jinja2Templates
from sqlalchemy.orm import Session

from app.auth import (
    create_session,
    destroy_session,
    get_current_user_web,
    hash_password,
    redirect_if_not_logged_in,
    verify_password,
)
from app.config import SECRET_KEY, SESSION_COOKIE_NAME, UPLOAD_DIR
from app.database import get_db
from app.models import Postcard, Profile, User

router = APIRouter(tags=["web"])
templates = Jinja2Templates(directory=str(Path(__file__).resolve().parent.parent / "templates"))


def _country_flag(code: str) -> str:
    if not code or len(code) != 2:
        return code or ""
    return chr(0x1F1E6 + ord(code[0].upper()) - ord("A")) + chr(0x1F1E6 + ord(code[1].upper()) - ord("A"))


templates.env.filters["flag"] = _country_flag


def _redirect(url: str) -> RedirectResponse:
    return RedirectResponse(url, status_code=303)


# ---------- Auth ----------

@router.get("/login", response_class=HTMLResponse)
def login_page(request: Request, db: Session = Depends(get_db)):
    user = redirect_if_not_logged_in(request, db)
    if user:
        return _redirect("/dashboard")
    return templates.TemplateResponse("login.html", {"request": request})


@router.post("/login")
def login_submit(
    request: Request,
    username: str = Form(...),
    password: str = Form(...),
    remember_me: str = Form(""),
    db: Session = Depends(get_db),
):
    from app.auth import cleanup_expired_sessions
    cleanup_expired_sessions(db)
    user = db.query(User).filter(User.username == username).first()
    if not user or not verify_password(password, user.password_hash):
        return templates.TemplateResponse(
            "login.html", {"request": request, "error": "用户名或密码错误"}, status_code=401
        )
    is_remember = remember_me == "on"
    token = create_session(user.id, db, remember_me=is_remember)
    resp = _redirect("/dashboard")
    cookie_kwargs = {"httponly": True, "samesite": "lax"}
    if is_remember:
        cookie_kwargs["max_age"] = 365 * 24 * 3600
    resp.set_cookie(SESSION_COOKIE_NAME, token, **cookie_kwargs)
    return resp


# ---------- Settings ----------

@router.get("/settings", response_class=HTMLResponse)
def settings_page(
    request: Request,
    user: User = Depends(get_current_user_web),
):
    return templates.TemplateResponse("settings.html", {"request": request, "user": user})


@router.post("/settings/change-username")
def change_username(
    request: Request,
    new_username: str = Form(...),
    user: User = Depends(get_current_user_web),
    db: Session = Depends(get_db),
):
    if db.query(User).filter(User.username == new_username, User.id != user.id).first():
        return templates.TemplateResponse(
            "settings.html", {"request": request, "user": user, "error": "用户名已存在"}, status_code=400
        )
    user.username = new_username
    db.commit()
    return templates.TemplateResponse(
        "settings.html", {"request": request, "user": user, "success": "用户名修改成功"}
    )


@router.post("/settings/change-password")
def change_password(
    request: Request,
    old_password: str = Form(...),
    new_password: str = Form(...),
    confirm_password: str = Form(...),
    user: User = Depends(get_current_user_web),
    db: Session = Depends(get_db),
):
    if not verify_password(old_password, user.password_hash):
        return templates.TemplateResponse(
            "settings.html", {"request": request, "user": user, "error": "当前密码错误"}, status_code=400
        )
    if new_password != confirm_password:
        return templates.TemplateResponse(
            "settings.html", {"request": request, "user": user, "error": "两次输入的新密码不一致"}, status_code=400
        )
    if len(new_password) < 6:
        return templates.TemplateResponse(
            "settings.html", {"request": request, "user": user, "error": "新密码长度至少6位"}, status_code=400
        )
    user.password_hash = hash_password(new_password)
    db.commit()
    return templates.TemplateResponse(
        "settings.html", {"request": request, "user": user, "success": "密码修改成功"}
    )


# ---------- Auth ----------

@router.get("/logout")
def logout(request: Request, db: Session = Depends(get_db)):
    token = request.cookies.get(SESSION_COOKIE_NAME)
    destroy_session(token or "", db)
    resp = _redirect("/login")
    resp.delete_cookie(SESSION_COOKIE_NAME)
    return resp


# ---------- Dashboard ----------

@router.get("/", response_class=HTMLResponse)
def root(user: User = Depends(get_current_user_web)):
    return _redirect("/dashboard")


@router.get("/dashboard", response_class=HTMLResponse)
def dashboard(request: Request, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    profiles = db.query(Profile).filter(Profile.user_id == user.id).all()
    stats = {}
    extras = {}
    for p in profiles:
        cards = db.query(Postcard).filter(Postcard.profile_id == p.id).order_by(Postcard.created_at.desc()).all()
        stats[p.id] = {
            "total": len(cards),
            "sent": sum(1 for c in cards if c.status == "sent"),
            "delivered": sum(1 for c in cards if c.status == "delivered"),
            "received": sum(1 for c in cards if c.status == "received"),
        }
        countries = sorted({c.country for c in cards if c.country})
        recent = cards[:3]
        extras[p.id] = {"countries": countries, "recent": recent}
    return templates.TemplateResponse("dashboard.html", {"request": request, "user": user, "profiles": profiles, "stats": stats, "extras": extras})


# ---------- Profiles ----------

@router.get("/profiles", response_class=HTMLResponse)
def profile_list(request: Request, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    profiles = db.query(Profile).filter(Profile.user_id == user.id).all()
    return templates.TemplateResponse("profiles.html", {"request": request, "user": user, "profiles": profiles})


@router.post("/profiles")
def profile_create(request: Request, nickname: str = Form(...), user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    db.add(Profile(user_id=user.id, nickname=nickname))
    db.commit()
    return _redirect("/profiles")


@router.post("/profiles/{profile_id}/delete")
def profile_delete(profile_id: int, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    p = db.query(Profile).filter(Profile.id == profile_id, Profile.user_id == user.id).first()
    if p:
        db.delete(p)
        db.commit()
    return _redirect("/profiles")


@router.post("/profiles/{profile_id}/rename")
def profile_rename(profile_id: int, nickname: str = Form(...), user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    p = db.query(Profile).filter(Profile.id == profile_id, Profile.user_id == user.id).first()
    if p:
        p.nickname = nickname
        db.commit()
    return _redirect("/profiles")


# ---------- Postcards ----------

@router.get("/profiles/{profile_id}/postcards", response_class=HTMLResponse)
def postcard_list(
    request: Request,
    profile_id: int,
    country: str = "",
    user: User = Depends(get_current_user_web),
    db: Session = Depends(get_db),
):
    profile = db.query(Profile).filter(Profile.id == profile_id, Profile.user_id == user.id).first()
    if not profile:
        return _redirect("/profiles")
    q = db.query(Postcard).filter(Postcard.profile_id == profile_id)
    if country:
        q = q.filter(Postcard.country == country)
    postcards = q.all()

    # collect existing countries for dropdown
    all_countries = sorted({pc.country for pc in db.query(Postcard.country).filter(Postcard.profile_id == profile_id, Postcard.country.isnot(None)).all()})

    # status sort order: sent=0, delivered=1, received=2
    _status_order = {"sent": 0, "delivered": 1, "received": 2}
    postcards.sort(key=lambda pc: (_status_order.get(pc.status, 9), -(pc.send_time or pc.arrival_time or pc.receive_time or pc.created_at).timestamp()))

    # split into sent and received
    sent = [pc for pc in postcards if pc.status in ("sent", "delivered")]
    received = [pc for pc in postcards if pc.status == "received"]

    return templates.TemplateResponse(
        "postcards.html",
        {"request": request, "user": user, "profile": profile, "sent": sent, "received": received, "countries": all_countries, "country": country},
    )


@router.get("/profiles/{profile_id}/postcards/new", response_class=HTMLResponse)
def postcard_new(request: Request, profile_id: int, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    profile = db.query(Profile).filter(Profile.id == profile_id, Profile.user_id == user.id).first()
    if not profile:
        return _redirect("/profiles")
    return templates.TemplateResponse("postcard_form.html", {"request": request, "user": user, "profile": profile, "postcard": None})


@router.post("/profiles/{profile_id}/postcards")
def postcard_create(
    request: Request,
    profile_id: int,
    card_number: str = Form(...),
    status: str = Form(...),
    recipient_name: str = Form(""),
    country: str = Form(""),
    send_time: str = Form(""),
    arrival_time: str = Form(""),
    sender_name: str = Form(""),
    receive_time: str = Form(""),
    user: User = Depends(get_current_user_web),
    db: Session = Depends(get_db),
):
    profile = db.query(Profile).filter(Profile.id == profile_id, Profile.user_id == user.id).first()
    if not profile:
        return _redirect("/profiles")

    def _parse_dt(s: str) -> datetime | None:
        s = s.strip()
        if not s:
            return None
        try:
            return datetime.fromisoformat(s)
        except ValueError:
            try:
                return datetime.strptime(s, "%Y-%m-%d")
            except ValueError:
                return None

    pc = Postcard(
        profile_id=profile_id,
        card_number=card_number,
        status=status,
        recipient_name=recipient_name or None,
        country=(country.strip().upper() if country else None),
        send_time=_parse_dt(send_time),
        arrival_time=_parse_dt(arrival_time),
        sender_name=sender_name or None,
        receive_time=_parse_dt(receive_time),
    )
    db.add(pc)
    db.commit()
    return _redirect(f"/profiles/{profile_id}/postcards")


@router.get("/postcards/{postcard_id}", response_class=HTMLResponse)
def postcard_detail(request: Request, postcard_id: int, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    pc = (
        db.query(Postcard)
        .join(Profile)
        .filter(Postcard.id == postcard_id, Profile.user_id == user.id)
        .first()
    )
    if not pc:
        return _redirect("/profiles")
    return templates.TemplateResponse("postcard_detail.html", {"request": request, "user": user, "postcard": pc})


@router.get("/postcards/{postcard_id}/edit", response_class=HTMLResponse)
def postcard_edit(request: Request, postcard_id: int, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    pc = (
        db.query(Postcard)
        .join(Profile)
        .filter(Postcard.id == postcard_id, Profile.user_id == user.id)
        .first()
    )
    if not pc:
        return _redirect("/profiles")
    return templates.TemplateResponse("postcard_form.html", {"request": request, "user": user, "profile": pc.profile, "postcard": pc})


@router.post("/postcards/{postcard_id}/edit")
def postcard_update(
    request: Request,
    postcard_id: int,
    card_number: str = Form(...),
    status: str = Form(...),
    recipient_name: str = Form(""),
    country: str = Form(""),
    send_time: str = Form(""),
    arrival_time: str = Form(""),
    sender_name: str = Form(""),
    receive_time: str = Form(""),
    user: User = Depends(get_current_user_web),
    db: Session = Depends(get_db),
):
    pc = (
        db.query(Postcard)
        .join(Profile)
        .filter(Postcard.id == postcard_id, Profile.user_id == user.id)
        .first()
    )
    if not pc:
        return _redirect("/profiles")

    def _parse_dt(s: str) -> datetime | None:
        s = s.strip()
        if not s:
            return None
        try:
            return datetime.fromisoformat(s)
        except ValueError:
            try:
                return datetime.strptime(s, "%Y-%m-%d")
            except ValueError:
                return None

    pc.card_number = card_number
    pc.status = status
    pc.recipient_name = recipient_name or None
    pc.country = country or None
    pc.send_time = _parse_dt(send_time)
    pc.arrival_time = None if status == "sent" else _parse_dt(arrival_time)
    pc.sender_name = sender_name or None
    pc.receive_time = _parse_dt(receive_time)
    db.commit()
    return _redirect(f"/postcards/{postcard_id}")


@router.post("/postcards/{postcard_id}/delete")
def postcard_delete(postcard_id: int, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    pc = (
        db.query(Postcard)
        .join(Profile)
        .filter(Postcard.id == postcard_id, Profile.user_id == user.id)
        .first()
    )
    if not pc:
        return _redirect("/profiles")
    pid = pc.profile_id
    db.delete(pc)
    db.commit()
    return _redirect(f"/profiles/{pid}/postcards")


@router.post("/postcards/{postcard_id}/mark-delivered")
def mark_delivered(
    postcard_id: int,
    user: User = Depends(get_current_user_web),
    db: Session = Depends(get_db),
):
    pc = (
        db.query(Postcard)
        .join(Profile)
        .filter(Postcard.id == postcard_id, Profile.user_id == user.id)
        .first()
    )
    if not pc:
        return _redirect("/profiles")
    pc.status = "delivered"
    if not pc.arrival_time:
        pc.arrival_time = datetime.now()
    db.commit()
    return _redirect(f"/postcards/{postcard_id}")


# ---------- Image Upload ----------

@router.post("/postcards/{postcard_id}/image/{side}")
async def upload_image(
    postcard_id: int,
    side: str,
    file: UploadFile = File(...),
    user: User = Depends(get_current_user_web),
    db: Session = Depends(get_db),
):
    if side not in ("front", "back"):
        return _redirect("/profiles")
    pc = (
        db.query(Postcard)
        .join(Profile)
        .filter(Postcard.id == postcard_id, Profile.user_id == user.id)
        .first()
    )
    if not pc:
        return _redirect("/profiles")
    ext = Path(file.filename or "upload.jpg").suffix or ".jpg"
    filename = f"{uuid4().hex}{ext}"
    dest = UPLOAD_DIR / filename
    content = await file.read()
    dest.write_bytes(content)
    setattr(pc, f"image_{side}", f"/uploads/{filename}")
    db.commit()
    return _redirect(f"/postcards/{postcard_id}")


# ---------- API Keys ----------

@router.get("/api-keys", response_class=HTMLResponse)
def api_keys_page(request: Request, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    keys = db.query(ApiKey).filter(ApiKey.user_id == user.id).all()
    return templates.TemplateResponse("api_keys.html", {"request": request, "user": user, "keys": keys})


@router.post("/api-keys")
def api_key_create(user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    ak = ApiKey(user_id=user.id, key=ApiKey.generate_key())
    db.add(ak)
    db.commit()
    return _redirect("/api-keys")


@router.post("/api-keys/{key_id}/delete")
def api_key_delete(key_id: int, user: User = Depends(get_current_user_web), db: Session = Depends(get_db)):
    ak = db.query(ApiKey).filter(ApiKey.id == key_id, ApiKey.user_id == user.id).first()
    if ak:
        db.delete(ak)
        db.commit()
    return _redirect("/api-keys")