"""Shaders router — CRUD, submit, fork, search."""

from uuid import UUID
from datetime import datetime, timezone
from fastapi import APIRouter, Depends, HTTPException, Query, status
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, func

from app.database import get_db
from app.models import User, Shader
from app.schemas import ShaderCreate, ShaderUpdate, ShaderPublic
from app.middleware.auth import get_current_user, get_optional_user
from app.services.glsl_validator import validate_glsl

router = APIRouter()


@router.get("", response_model=list[ShaderPublic])
async def list_shaders(
    q: str | None = Query(None, description="Search query"),
    tags: list[str] | None = Query(None, description="Filter by tags"),
    shader_type: str | None = Query(None, description="Filter by type: 2d, 3d, audio-reactive"),
    sort: str = Query("trending", description="Sort: trending, new, top"),
    limit: int = Query(20, ge=1, le=50),
    offset: int = Query(0, ge=0),
    db: AsyncSession = Depends(get_db),
):
    query = select(Shader).where(Shader.is_public == True, Shader.render_status == "ready")

    if q:
        query = query.where(Shader.title.ilike(f"%{q}%"))
    if tags:
        query = query.where(Shader.tags.overlap(tags))
    if shader_type:
        query = query.where(Shader.shader_type == shader_type)

    if sort == "new":
        query = query.order_by(Shader.created_at.desc())
    elif sort == "top":
        query = query.order_by(Shader.score.desc())
    else:  # trending
        query = query.order_by(Shader.score.desc(), Shader.created_at.desc())

    query = query.limit(limit).offset(offset)
    result = await db.execute(query)
    return result.scalars().all()


@router.get("/{shader_id}", response_model=ShaderPublic)
async def get_shader(
    shader_id: UUID,
    db: AsyncSession = Depends(get_db),
    user: User | None = Depends(get_optional_user),
):
    result = await db.execute(select(Shader).where(Shader.id == shader_id))
    shader = result.scalar_one_or_none()
    if not shader:
        raise HTTPException(status_code=404, detail="Shader not found")

    if not shader.is_public and (not user or user.id != shader.author_id):
        raise HTTPException(status_code=404, detail="Shader not found")

    # Increment view count
    shader.view_count += 1
    return shader


@router.post("", response_model=ShaderPublic, status_code=status.HTTP_201_CREATED)
async def create_shader(
    body: ShaderCreate,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    # Rate limit: free tier gets 5 submissions/month
    if user.subscription_tier == "free":
        month_start = datetime.now(timezone.utc).replace(day=1, hour=0, minute=0, second=0, microsecond=0)
        count_result = await db.execute(
            select(func.count()).select_from(Shader).where(
                Shader.author_id == user.id,
                Shader.created_at >= month_start,
            )
        )
        monthly_count = count_result.scalar()
        if monthly_count >= 5:
            raise HTTPException(
                status_code=429,
                detail="Free tier: 5 shader submissions per month. Upgrade to Pro for unlimited."
            )

    # Validate GLSL
    validation = validate_glsl(body.glsl_code, body.shader_type)
    if not validation.valid:
        raise HTTPException(
            status_code=422,
            detail={
                "message": "GLSL validation failed",
                "errors": validation.errors,
                "warnings": validation.warnings,
            }
        )

    shader = Shader(
        author_id=user.id,
        title=body.title,
        description=body.description,
        glsl_code=body.glsl_code,
        tags=body.tags,
        shader_type=body.shader_type,
        is_public=body.is_public,
        style_metadata=body.style_metadata,
        render_status="pending",
    )
    db.add(shader)
    await db.flush()

    # Enqueue render job
    from app.worker import celery_app
    try:
        celery_app.send_task("render_shader", args=[str(shader.id)])
    except Exception:
        # If Celery isn't available (dev without worker), mark as ready
        # with no thumbnail — the frontend can still render live
        shader.render_status = "ready"

    # If this shader fulfills a desire, link them
    if body.fulfills_desire_id:
        from app.models import Desire
        desire = (await db.execute(
            select(Desire).where(Desire.id == body.fulfills_desire_id, Desire.status == "open")
        )).scalar_one_or_none()
        if desire:
            desire.status = "fulfilled"
            desire.fulfilled_by_shader = shader.id
            desire.fulfilled_at = datetime.now(timezone.utc)

    return shader


@router.put("/{shader_id}", response_model=ShaderPublic)
async def update_shader(
    shader_id: UUID,
    body: ShaderUpdate,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    result = await db.execute(select(Shader).where(Shader.id == shader_id))
    shader = result.scalar_one_or_none()
    if not shader:
        raise HTTPException(status_code=404, detail="Shader not found")
    if shader.author_id != user.id and user.role != "admin":
        raise HTTPException(status_code=403, detail="Not the shader owner")

    updates = body.model_dump(exclude_unset=True)

    # Re-validate GLSL if code changed
    if "glsl_code" in updates:
        validation = validate_glsl(updates["glsl_code"], shader.shader_type)
        if not validation.valid:
            raise HTTPException(
                status_code=422,
                detail={
                    "message": "GLSL validation failed",
                    "errors": validation.errors,
                    "warnings": validation.warnings,
                }
            )
        # Re-render if code changed
        shader.render_status = "pending"
        from app.worker import celery_app
        try:
            celery_app.send_task("render_shader", args=[str(shader.id)])
        except Exception:
            shader.render_status = "ready"

    for field, value in updates.items():
        setattr(shader, field, value)

    shader.updated_at = datetime.now(timezone.utc)
    return shader


@router.delete("/{shader_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_shader(
    shader_id: UUID,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    result = await db.execute(select(Shader).where(Shader.id == shader_id))
    shader = result.scalar_one_or_none()
    if not shader:
        raise HTTPException(status_code=404, detail="Shader not found")
    if shader.author_id != user.id and user.role != "admin":
        raise HTTPException(status_code=403, detail="Not the shader owner")

    await db.delete(shader)


@router.post("/{shader_id}/fork", response_model=ShaderPublic, status_code=status.HTTP_201_CREATED)
async def fork_shader(
    shader_id: UUID,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    result = await db.execute(select(Shader).where(Shader.id == shader_id))
    original = result.scalar_one_or_none()
    if not original:
        raise HTTPException(status_code=404, detail="Shader not found")
    if not original.is_public:
        raise HTTPException(status_code=404, detail="Shader not found")

    forked = Shader(
        author_id=user.id,
        title=f"Fork of {original.title}",
        description=f"Forked from {original.title}",
        glsl_code=original.glsl_code,
        tags=original.tags,
        shader_type=original.shader_type,
        forked_from=original.id,
        style_metadata=original.style_metadata,
        render_status="pending",
    )
    db.add(forked)
    await db.flush()

    # Enqueue render for the fork
    from app.worker import celery_app
    try:
        celery_app.send_task("render_shader", args=[str(forked.id)])
    except Exception:
        forked.render_status = "ready"

    return forked