"""
sync.py — Push/pull synkronisering mellem lokal app og server.

POST /sync/push  — send lokal data op til server
GET  /sync/pull  — hent server-data ned til app
"""
from datetime import datetime, timezone
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from pydantic import BaseModel
from typing import Optional

from app.core.database import get_db
from app.core.security import get_current_user
from app.models import (
    User, Song, Dance, DanceLevel, Project, ProjectSong,
    PlaylistShare, CommunityDance, CommunityDanceAlt,
)

router = APIRouter(prefix="/sync", tags=["sync"])


# ── Schemas ───────────────────────────────────────────────────────────────────

class SongData(BaseModel):
    local_id:     str
    title:        str
    artist:       str = ""
    album:        str = ""
    bpm:          int = 0
    duration_sec: int = 0
    file_format:  str = ""

class DanceData(BaseModel):
    name:          str
    level_name:    str = ""
    choreographer: str = ""
    video_url:     str = ""
    stepsheet_url: str = ""
    notes:         str = ""

class SongDanceData(BaseModel):
    song_local_id:  str
    dance_name:     str
    level_name:     str = ""
    dance_order:    int = 1

class SongAltDanceData(BaseModel):
    song_local_id:  str
    dance_name:     str
    level_name:     str = ""
    note:           str = ""

class PlaylistSongData(BaseModel):
    song_local_id:  str
    position:       int
    status:         str = "pending"
    is_workshop:    bool = False
    dance_override: str = ""

class PlaylistData(BaseModel):
    local_id:    str
    name:        str
    description: str = ""
    tags:        str = ""
    visibility:  str = "private"
    songs:       list[PlaylistSongData] = []

class PushPayload(BaseModel):
    songs:      list[SongData] = []
    dances:     list[DanceData] = []
    song_dances: list[SongDanceData] = []
    song_alts:  list[SongAltDanceData] = []
    playlists:  list[PlaylistData] = []


# ── Push ──────────────────────────────────────────────────────────────────────

@router.post("/push")
def push(
    payload: PushPayload,
    db: Session = Depends(get_db),
    me: User = Depends(get_current_user),
):
    """Upload lokal data til server. Returnerer server-IDs."""
    song_id_map = {}    # local_id → server Song.id
    dance_id_map = {}   # "name|level" → server Dance.id
    level_map = {}      # level_name → DanceLevel.id

    # ── Dans-niveauer ─────────────────────────────────────────────────────────
    for lvl in db.query(DanceLevel).all():
        level_map[lvl.name.lower()] = lvl.id

    # ── Sange ─────────────────────────────────────────────────────────────────
    for s in payload.songs:
        if not s.title:
            continue
        # Match globalt på titel+artist — samme sang deles på tværs af brugere
        existing = db.query(Song).filter(
            Song.title == s.title,
            Song.artist == s.artist,
        ).first()
        if existing:
            song_id_map[s.local_id] = existing.id
            # Opdater BPM hvis det mangler
            if s.bpm and not existing.bpm:
                existing.bpm = s.bpm
        else:
            song = Song(
                owner_id=me.id,
                title=s.title, artist=s.artist, album=s.album,
                bpm=s.bpm, duration_sec=s.duration_sec,
                file_format=s.file_format,
            )
            db.add(song)
            db.flush()
            song_id_map[s.local_id] = song.id

    # ── Danse ──────────────────────────────────────────────────────────────────
    for d in payload.dances:
        level_id = level_map.get(d.level_name.lower()) if d.level_name else None
        key = f"{d.name.lower()}|{level_id}"
        existing = db.query(Dance).filter_by(name=d.name, level_id=level_id).first()
        if existing:
            # Opdater info hvis den har ny data
            if d.choreographer:  existing.choreographer = d.choreographer
            if d.video_url:      existing.video_url = d.video_url
            if d.stepsheet_url:  existing.stepsheet_url = d.stepsheet_url
            if d.notes:          existing.notes = d.notes
            dance_id_map[key] = existing.id
        else:
            dance = Dance(
                name=d.name, level_id=level_id,
                choreographer=d.choreographer, video_url=d.video_url,
                stepsheet_url=d.stepsheet_url, notes=d.notes,
            )
            db.add(dance)
            db.flush()
            dance_id_map[key] = dance.id

    # ── Community dans-tags ────────────────────────────────────────────────────
    for sd in payload.song_dances:
        song_id = song_id_map.get(sd.song_local_id)
        if not song_id:
            continue
        song = db.query(Song).filter_by(id=song_id).first()
        level_id = level_map.get(sd.level_name.lower()) if sd.level_name else None
        key = f"{sd.dance_name.lower()}|{level_id}"
        dance_id = dance_id_map.get(key)
        if not dance_id:
            continue
        # Indsend som community dans-tag
        existing = db.query(CommunityDance).filter_by(
            song_title=song.title, song_artist=song.artist, dance_id=dance_id
        ).first()
        if not existing:
            cd = CommunityDance(
                song_title=song.title, song_artist=song.artist,
                dance_id=dance_id, submitted_by=me.id,
            )
            db.add(cd)

    # ── Playlister ────────────────────────────────────────────────────────────
    playlist_id_map = {}
    for pl in payload.playlists:
        existing = db.query(Project).filter_by(
            owner_id=me.id, name=pl.name
        ).first()
        if existing:
            existing.description = pl.description
            existing.visibility  = pl.visibility
            # Slet og geninsert sange
            db.query(ProjectSong).filter_by(project_id=existing.id).delete()
            project = existing
        else:
            project = Project(
                owner_id=me.id, name=pl.name,
                description=pl.description, visibility=pl.visibility,
            )
            db.add(project)
            db.flush()
        playlist_id_map[pl.local_id] = project.id

        for ps in pl.songs:
            song_id = song_id_map.get(ps.song_local_id)
            if not song_id:
                continue
            proj_song = ProjectSong(
                project_id=project.id, song_id=song_id,
                position=ps.position, status=ps.status,
                is_workshop=ps.is_workshop,
                dance_override=ps.dance_override,
            )
            db.add(proj_song)

    db.commit()

    return {
        "status": "ok",
        "songs_synced":     len(song_id_map),
        "playlists_synced": len(playlist_id_map),
        "song_id_map":      song_id_map,
        "playlist_id_map":  playlist_id_map,
    }


# ── Pull ──────────────────────────────────────────────────────────────────────

@router.get("/pull")
def pull(
    db: Session = Depends(get_db),
    me: User = Depends(get_current_user),
):
    """Hent server-data til lokal app."""

    # Dans-niveauer
    levels = [
        {"id": l.id, "name": l.name, "sort_order": l.sort_order}
        for l in db.query(DanceLevel).order_by(DanceLevel.sort_order).all()
    ]

    # Danse med info
    dances = [
        {
            "name": d.name,
            "level_id": d.level_id,
            "choreographer": d.choreographer,
            "video_url": d.video_url,
            "stepsheet_url": d.stepsheet_url,
            "notes": d.notes,
            "use_count": d.use_count,
        }
        for d in db.query(Dance).order_by(Dance.use_count.desc()).limit(500).all()
    ]

    # Community dans-tags (populære)
    community = []
    for cd in db.query(CommunityDance).limit(1000).all():
        community.append({
            "song_title":  cd.song_title,
            "song_artist": cd.song_artist,
            "dance_id":    cd.dance_id,
        })

    # Delte playlister
    shared_ids = [
        s.project_id for s in
        db.query(PlaylistShare).filter_by(shared_with_id=me.id).all()
    ]
    shared = []
    for p in db.query(Project).filter(Project.id.in_(shared_ids)).all():
        shared.append({
            "id":          p.id,
            "name":        p.name,
            "owner_id":    p.owner_id,
            "visibility":  p.visibility,
            "songs": [
                {
                    "song_id":       ps.song_id,
                    "position":      ps.position,
                    "status":        ps.status,
                    "is_workshop":   ps.is_workshop,
                    "dance_override": ps.dance_override,
                }
                for ps in p.project_songs
            ]
        })

    return {
        "levels":    levels,
        "dances":    dances,
        "community": community,
        "shared":    shared,
    }