import os
import time
from typing import List, Dict

from fastapi import FastAPI, UploadFile, File, Depends
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from sqlalchemy.orm import Session

from .db import Base, engine, SessionLocal
from .models import ExtractionRecord
from .schemas import ExtractionRecordBase, ExtractionStage
from .openrouter_client import extract_fields_from_document

# Ensure data dir exists for SQLite
os.makedirs("data", exist_ok=True)

# Create tables
Base.metadata.create_all(bind=engine)

app = FastAPI(title="Document Capture Demo – Backend")

# CORS (for safety we allow all; you can tighten later)
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


@app.get("/ping")
def ping():
    """Healthcheck."""
    return {"status": "ok", "message": "backend alive"}


def make_stages(total_ms: int, status: str) -> Dict[str, ExtractionStage]:
    """
    Build synthetic stage timing data for the History UI.
    For now we just split total_ms into 4 stages.
    """
    if total_ms <= 0:
        total_ms = 1000

    return {
        "uploading": ExtractionStage(
            time=int(total_ms * 0.15),
            status="completed",
            variation="normal",
        ),
        "aiAnalysis": ExtractionStage(
            time=int(total_ms * 0.55),
            status="completed" if status == "completed" else "failed",
            variation="normal",
        ),
        "dataExtraction": ExtractionStage(
            time=int(total_ms * 0.2),
            status="completed" if status == "completed" else "skipped",
            variation="fast",
        ),
        "outputRendering": ExtractionStage(
            time=int(total_ms * 0.1),
            status="completed" if status == "completed" else "skipped",
            variation="normal",
        ),
    }


@app.post("/api/extract")
async def extract_document(
    file: UploadFile = File(...),
    db: Session = Depends(get_db),
):
    """
    Main extraction endpoint used by the Dashboard.
    1) Read the uploaded file
    2) Call OpenRouter + Qwen3-VL
    3) Store a record in SQLite
    4) Return extraction result + metadata
    """
    start = time.time()
    content = await file.read()
    content_type = file.content_type or "application/octet-stream"
    size_mb = len(content) / 1024 / 1024
    size_str = f"{size_mb:.2f} MB"

    try:
        print(f"[INFO] Starting extraction for file: {file.filename}, type: {content_type}, size: {size_str}")
        extracted = await extract_fields_from_document(content, content_type, file.filename)
        total_ms = int((time.time() - start) * 1000)

        print(f"[INFO] Extraction completed. Response keys: {list(extracted.keys())}")
        print(f"[INFO] Fields extracted: {extracted.get('fields', {})}")

        confidence = float(extracted.get("confidence", 90))
        fields = extracted.get("fields", {})
        
        # Include full_text in fields if present (for frontend display)
        full_text = extracted.get("full_text", "")
        if full_text:
            fields["full_text"] = full_text
            full_text_words = len(str(full_text).split())
            print(f"[INFO] Full text extracted: {full_text_words} words")
        
        # Also check for pages array
        pages_data = extracted.get("pages", [])
        if pages_data and isinstance(pages_data, list):
            print(f"[INFO] Extracted text from {len(pages_data)} page(s)")
            # Add pages to fields for frontend
            fields["pages"] = pages_data
        
        # Count fields, including full_text if present
        fields_extracted = len(fields) if isinstance(fields, dict) else 0

        print(f"[INFO] Final stats - confidence: {confidence}, fields_count: {fields_extracted}")

        status = "completed"
        error_message = None
    except Exception as e:
        import traceback
        total_ms = int((time.time() - start) * 1000)
        confidence = 0.0
        fields = {}
        fields_extracted = 0
        status = "failed"
        error_message = str(e)
        print(f"[ERROR] Extraction failed: {error_message}")
        print(f"[ERROR] Traceback: {traceback.format_exc()}")

    # Save record to DB
    rec = ExtractionRecord(
        file_name=file.filename,
        file_type=content_type,
        file_size=size_str,
        status=status,
        confidence=confidence,
        fields_extracted=fields_extracted,
        total_time_ms=total_ms,
        raw_output=str(fields),
        error_message=error_message,
    )
    db.add(rec)
    db.commit()
    db.refresh(rec)

    stages = make_stages(total_ms, status)

    # Response shape that frontend will consume
    return {
        "id": rec.id,
        "fileName": rec.file_name,
        "fileType": rec.file_type,
        "fileSize": rec.file_size,
        "status": status,
        "confidence": confidence,
        "fieldsExtracted": fields_extracted,
        "totalTime": total_ms,
        "fields": fields,
        "stages": {k: v.dict() for k, v in stages.items()},
        "errorMessage": error_message,
    }


@app.get("/api/history", response_model=List[ExtractionRecordBase])
def get_history(db: Session = Depends(get_db)):
    """
    Used by the History page.
    Returns last 100 records, with synthetic stage data.
    """
    recs = (
        db.query(ExtractionRecord)
        .order_by(ExtractionRecord.created_at.desc())
        .limit(100)
        .all()
    )

    output: List[ExtractionRecordBase] = []
    for r in recs:
        stages = make_stages(r.total_time_ms or 1000, r.status or "completed")
        output.append(
            ExtractionRecordBase(
                id=r.id,
                fileName=r.file_name,
                fileType=r.file_type or "",
                fileSize=r.file_size or "",
                extractedAt=r.created_at,
                status=r.status or "completed",
                confidence=r.confidence or 0.0,
                fieldsExtracted=r.fields_extracted or 0,
                totalTime=r.total_time_ms or 0,
                stages=stages,
                errorMessage=r.error_message,
            )
        )
    return output


# Static frontend mounting (used after we build React)
# Dockerfile copies the Vite build into backend/frontend_dist
# IMPORTANT: API routes must be defined BEFORE this so they take precedence
frontend_dir = os.path.join(
    os.path.dirname(os.path.dirname(__file__)), "frontend_dist"
)

if os.path.isdir(frontend_dir):
    # Serve static files (JS, CSS, images, etc.) from assets directory
    assets_dir = os.path.join(frontend_dir, "assets")
    if os.path.isdir(assets_dir):
        app.mount(
            "/assets",
            StaticFiles(directory=assets_dir),
            name="assets",
        )
    
    # Serve static files from root (logo.png, favicon.ico, etc.)
    # Files in public/ directory are copied to dist/ root during Vite build
    # These routes must be defined BEFORE the catch-all route
    @app.get("/logo.png")
    async def serve_logo():
        """Serve logo.png from frontend_dist root."""
        from fastapi.responses import FileResponse
        logo_path = os.path.join(frontend_dir, "logo.png")
        if os.path.exists(logo_path):
            return FileResponse(logo_path, media_type="image/png")
        from fastapi import HTTPException
        raise HTTPException(status_code=404)
    
    @app.get("/favicon.ico")
    async def serve_favicon():
        """Serve favicon.ico from frontend_dist root."""
        from fastapi.responses import FileResponse
        favicon_path = os.path.join(frontend_dir, "favicon.ico")
        if os.path.exists(favicon_path):
            return FileResponse(favicon_path, media_type="image/x-icon")
        from fastapi import HTTPException
        raise HTTPException(status_code=404)
    
    # Catch-all route to serve index.html for React Router
    # This must be last so API routes and static files are matched first
    @app.get("/{full_path:path}")
    async def serve_frontend(full_path: str):
        """
        Serve React app for all non-API routes.
        React Router will handle client-side routing.
        """
        # Skip API routes, docs, static assets, and known static files
        if (full_path.startswith("api/") or 
            full_path.startswith("docs") or 
            full_path.startswith("openapi.json") or
            full_path.startswith("assets/") or
            full_path in ["logo.png", "favicon.ico"]):
            from fastapi import HTTPException
            raise HTTPException(status_code=404)
        
        # Serve index.html for all other routes (React Router will handle routing)
        from fastapi.responses import FileResponse
        index_path = os.path.join(frontend_dir, "index.html")
        if os.path.exists(index_path):
            return FileResponse(index_path)
        from fastapi import HTTPException
        raise HTTPException(status_code=404)