"""
FastAPI Application - AI Reel Creator Platform API
RESTful endpoints for reel generation pipeline.
"""

import logging
from contextlib import asynccontextmanager
from typing import Optional
from uuid import UUID

from fastapi import FastAPI, HTTPException, BackgroundTasks, File, UploadFile, Depends
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel, Field

from ..models.schemas import (
    ReelQueryRequest,
    ReelQueryResponse,
    ReelRequest,
    RequestStatus,
    DurationTarget,
    Platform,
    Tone,
    AspectRatio,
    ReelScript,
    ReelManifest,
    AssetSwapRequest,
    RegenerateRequest,
)

logger = logging.getLogger(__name__)

# ============================================================
# APP LIFECYCLE
# ============================================================

@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifespan events."""
    logger.info("AI Reel Creator Platform API starting...")
    yield
    logger.info("AI Reel Creator Platform API shutting down...")


app = FastAPI(
    title="AI Reel Creator Platform",
    description="End-to-end reel generation from raw assets to editable video output",
    version="1.0.0",
    lifespan=lifespan,
)

# CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


# ============================================================
# REQUEST/RESPONSE MODELS
# ============================================================

class CreateReelRequest(BaseModel):
    """Request to create a new reel."""
    user_query: str = Field(..., min_length=5, max_length=2000, 
                           description="Description of the desired reel")
    duration_target: str = Field(default="20s", 
                                 description="Target duration: 10s, 20s, 30s, 60s, or custom")
    platform: str = Field(default="instagram_reels",
                          description="Target platform: instagram_reels, tiktok, youtube_shorts, etc.")
    tone: str = Field(default="sporty",
                      description="Reel tone: sporty, elegant, technical, luxury, adventure, minimal, dynamic, serene")
    aspect_ratio: Optional[str] = Field(default=None,
                                       description="Aspect ratio: 9:16, 16:9, 1:1, 4:5")
    brand_config_id: Optional[str] = Field(default=None,
                                           description="UUID of brand config to use")
    additional_constraints: Optional[dict] = Field(default=None,
                                                   description="Extra constraints: must_include, avoid_parts, etc.")


class ReelStatusResponse(BaseModel):
    """Status of a reel generation request."""
    request_id: str
    status: str
    progress_percent: Optional[int] = None
    message: Optional[str] = None
    reel_script: Optional[dict] = None
    reel_manifest: Optional[dict] = None
    render_url: Optional[str] = None


class ReelManifestResponse(BaseModel):
    """Complete reel manifest with all resolved assets."""
    request_id: str
    manifest: dict
    preview_available: bool = False
    preview_url: Optional[str] = None


class SwapAssetRequest(BaseModel):
    """Request to swap an asset for a specific beat."""
    request_id: str
    beat_number: int = Field(..., ge=1, description="Beat number to modify")
    new_asset_id: str = Field(..., description="UUID of the replacement asset")
    new_video_event_id: Optional[str] = Field(default=None,
                                              description="UUID of replacement video event (for video assets)")


class SwapAssetResponse(BaseModel):
    """Response after asset swap."""
    request_id: str
    beat_number: int
    new_asset_id: str
    new_file_path: str
    manifest_updated: bool = True


class OrchestratorStatus(BaseModel):
    """System health and pipeline status."""
    status: str
    version: str = "1.0.0"
    active_requests: int = 0
    completed_requests: int = 0
    failed_requests: int = 0


# ============================================================
# IN-MEMORY STATE (replace with DB in production)
# ============================================================

_requests: dict[str, ReelRequest] = {}
_scripts: dict[str, ReelScript] = {}
_manifests: dict[str, ReelManifest] = {}
_stats = {"active": 0, "completed": 0, "failed": 0}


# ============================================================
# ENDPOINTS
# ============================================================

@app.get("/health", response_model=OrchestratorStatus)
async def health_check():
    """Health check endpoint."""
    return OrchestratorStatus(
        status="healthy",
        active_requests=_stats["active"],
        completed_requests=_stats["completed"],
        failed_requests=_stats["failed"],
    )


@app.post("/api/v1/reels/create", response_model=ReelQueryResponse)
async def create_reel(request: CreateReelRequest, background_tasks: BackgroundTasks):
    """
    Create a new reel generation request.
    
    This endpoint validates the user query, creates a ReelRequest,
    and initiates the planning pipeline. Returns a request_id for polling.
    """
    try:
        from ..pipelines.query_interface import QueryInterface
        
        # Convert to ReelQueryRequest
        query = ReelQueryRequest(
            user_query=request.user_query,
            duration_target=DurationTarget(request.duration_target),
            platform=Platform(request.platform),
            tone=Tone(request.tone),
            aspect_ratio=AspectRatio(request.aspect_ratio) if request.aspect_ratio else None,
            brand_config_id=request.brand_config_id,
            additional_constraints=request.additional_constraints,
        )
        
        interface = QueryInterface()
        brand_uuid = UUID(request.brand_config_id) if request.brand_config_id else None
        
        reel_request = interface.create_reel_request(query, brand_config_id=brand_uuid)
        
        # Store for tracking
        _requests[str(reel_request.id)] = reel_request
        _stats["active"] += 1
        
        # In production: dispatch to orchestrator pipeline
        # background_tasks.add_task(orchestrator_pipeline, reel_request)
        
        return ReelQueryResponse(
            request_id=str(reel_request.id),
            status=RequestStatus.PLANNING,
            message="Reel request accepted and planning has begun",
            estimated_completion_seconds=30,
        )
        
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        logger.exception("Error creating reel request")
        raise HTTPException(status_code=500, detail="Internal server error")


@app.get("/api/v1/reels/{request_id}/status", response_model=ReelStatusResponse)
async def get_reel_status(request_id: str):
    """
    Get the current status of a reel generation request.
    
    Poll this endpoint to track progress through:
    PENDING -> PLANNING -> GENERATING -> REVIEW -> COMPLETED
    """
    reel_request = _requests.get(request_id)
    if not reel_request:
        raise HTTPException(status_code=404, detail="Request not found")
    
    # Determine progress
    status_map = {
        RequestStatus.PENDING: 5,
        RequestStatus.PLANNING: 25,
        RequestStatus.GENERATING: 50,
        RequestStatus.REVIEW: 75,
        RequestStatus.COMPLETED: 100,
        RequestStatus.FAILED: 0,
    }
    
    progress = status_map.get(reel_request.status, 0)
    
    response = ReelStatusResponse(
        request_id=request_id,
        status=reel_request.status.value,
        progress_percent=progress,
        message=f"Current status: {reel_request.status.value}",
    )
    
    # Include script/manifest if available
    if request_id in _scripts:
        response.reel_script = _scripts[request_id].model_dump()
    if request_id in _manifests:
        response.reel_manifest = _manifests[request_id].model_dump()
    
    return response


@app.get("/api/v1/reels/{request_id}/script", response_model=ReelStatusResponse)
async def get_reel_script(request_id: str):
    """Get the generated reel script for a request."""
    if request_id not in _scripts:
        raise HTTPException(status_code=404, detail="Script not yet generated or request not found")
    
    return ReelStatusResponse(
        request_id=request_id,
        status="script_ready",
        reel_script=_scripts[request_id].model_dump(),
    )


@app.get("/api/v1/reels/{request_id}/manifest", response_model=ReelManifestResponse)
async def get_reel_manifest(request_id: str):
    """Get the complete reel manifest with resolved assets."""
    if request_id not in _manifests:
        raise HTTPException(status_code=404, detail="Manifest not yet generated or request not found")
    
    manifest = _manifests[request_id]
    
    return ReelManifestResponse(
        request_id=request_id,
        manifest=manifest.model_dump(),
        preview_available=False,
    )


@app.post("/api/v1/reels/{request_id}/swap-asset", response_model=SwapAssetResponse)
async def swap_asset(request_id: str, swap: SwapAssetRequest):
    """
    Swap an asset for a specific beat in the reel manifest.
    
    Allows user to override the LLM-selected asset with one of the
    top-k candidates or any available asset.
    """
    if request_id not in _manifests:
        raise HTTPException(status_code=404, detail="Manifest not found")
    
    manifest = _manifests[request_id]
    
    # Find the beat to swap
    beat_found = False
    new_file_path = "unknown"
    
    for beat in manifest.beats:
        if beat.beat_number == swap.beat_number:
            beat.asset_id = UUID(swap.new_asset_id)
            if swap.new_video_event_id:
                beat.video_event_id = UUID(swap.new_video_event_id)
            new_file_path = beat.file_path  # Would update from asset DB
            beat_found = True
            break
    
    if not beat_found:
        raise HTTPException(status_code=400, detail=f"Beat {swap.beat_number} not found in manifest")
    
    return SwapAssetResponse(
        request_id=request_id,
        beat_number=swap.beat_number,
        new_asset_id=swap.new_asset_id,
        new_file_path=new_file_path,
        manifest_updated=True,
    )


@app.post("/api/v1/reels/{request_id}/regenerate", response_model=ReelQueryResponse)
async def regenerate_reel(request_id: str, request: CreateReelRequest):
    """
    Regenerate a reel with modified parameters while preserving the original request context.
    
    The new request is created as a child of the original, allowing comparison.
    """
    old_request = _requests.get(request_id)
    if not old_request:
        raise HTTPException(status_code=404, detail="Original request not found")
    
    # Create new request with updated parameters
    from ..pipelines.query_interface import QueryInterface
    
    new_query = ReelQueryRequest(
        user_query=request.user_query or old_request.user_query,
        duration_target=DurationTarget(request.duration_target) if request.duration_target else old_request.duration_target,
        platform=Platform(request.platform) if request.platform else old_request.platform,
        tone=Tone(request.tone) if request.tone else old_request.tone,
        aspect_ratio=AspectRatio(request.aspect_ratio) if request.aspect_ratio else old_request.aspect_ratio,
    )
    
    interface = QueryInterface()
    new_reel_request = interface.create_reel_request(
        new_query,
        brand_config_id=old_request.brand_config_id,
    )
    
    _requests[str(new_reel_request.id)] = new_reel_request
    _stats["active"] += 1
    
    return ReelQueryResponse(
        request_id=str(new_reel_request.id),
        status=RequestStatus.PLANNING,
        message="Regeneration request accepted",
        estimated_completion_seconds=30,
    )


@app.post("/api/v1/reels/{request_id}/render")
async def start_render(request_id: str, background_tasks: BackgroundTasks):
    """
    Start rendering the reel from the manifest.
    
    This triggers the FFmpeg composition pipeline (Phase 4).
    """
    if request_id not in _manifests:
        raise HTTPException(status_code=404, detail="Manifest not found - generate manifest first")
    
    # In production: background_tasks.add_task(render_pipeline, request_id)
    
    return {
        "request_id": request_id,
        "render_status": "queued",
        "message": "Render job queued for processing",
        "estimated_time_seconds": 120,
    }


@app.get("/api/v1/reels/{request_id}/render-status")
async def get_render_status(request_id: str):
    """Get the status of a render job."""
    return {
        "request_id": request_id,
        "render_status": "pending",  # pending, rendering, completed, failed
        "progress_percent": 0,
        "output_url": None,
    }


@app.get("/api/v1/reels/{request_id}/export/remotion")
async def export_remotion(request_id: str):
    """
    Export the reel manifest as a Remotion project (Phase 5).
    
    Returns a ZIP file containing the Remotion composition,
    assets, and package configuration.
    """
    if request_id not in _manifests:
        raise HTTPException(status_code=404, detail="Manifest not found")
    
    # In production: generate Remotion project and return download URL
    
    return {
        "request_id": request_id,
        "export_status": "ready",
        "download_url": f"/downloads/{request_id}/remotion_project.zip",
        "composition_file": "src/Composition.tsx",
    }


# ============================================================
# ASSET MANAGEMENT ENDPOINTS
# ============================================================

@app.post("/api/v1/assets/upload")
async def upload_asset(
    file: UploadFile = File(...),
    asset_type: str = "video",
    source: Optional[str] = None,
):
    """Upload a raw asset (video, image, or audio) to the asset database."""
    # In production: save to S3/R2, extract metadata, store in DB
    return {
        "asset_id": str(UUID(int=0)),  # placeholder
        "filename": file.filename,
        "asset_type": asset_type,
        "status": "uploaded",
        "metadata_extraction": "queued",
    }


@app.get("/api/v1/assets/search")
async def search_assets(
    query: str,
    asset_type: Optional[str] = None,
    limit: int = 10,
    subject_part: Optional[str] = None,
    mood: Optional[str] = None,
):
    """
    Search assets by semantic similarity using CLIP embeddings.
    
    Query is embedded via CLIP and matched against stored asset embeddings.
    """
    # In production: call embedding_store.search_assets(query_embedding, ...)
    return {
        "query": query,
        "results": [],
        "total": 0,
    }


# ============================================================
# BROCHURE MANAGEMENT ENDPOINTS
# ============================================================

@app.post("/api/v1/brochures/upload")
async def upload_brochure(
    file: UploadFile = File(...),
    brand_name: Optional[str] = None,
    background_tasks: BackgroundTasks = None,
):
    """
    Upload a brochure PDF for parsing.
    
    Triggers background processing: PDF -> nodes -> embeddings -> asset mapping.
    """
    # In production: queue brochure parsing pipeline
    return {
        "processing_id": str(UUID(int=0)),
        "filename": file.filename,
        "status": "queued",
        "estimated_nodes": None,
    }


@app.get("/api/v1/brochures/{brochure_id}/nodes")
async def get_brochure_nodes(brochure_id: str):
    """Get all brochure nodes for a parsed brochure."""
    return {
        "brochure_id": brochure_id,
        "nodes": [],
        "total_nodes": 0,
    }


@app.get("/api/v1/brochures/{brochure_id}/mappings")
async def get_brochure_mappings(brochure_id: str):
    """Get brochure-to-asset mappings for review."""
    return {
        "brochure_id": brochure_id,
        "mappings": [],
        "total_mappings": 0,
        "approved": 0,
        "pending": 0,
        "rejected": 0,
    }


# ============================================================
# RUN
# ============================================================

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)