from fastapi import APIRouter, Depends, HTTPException, BackgroundTasks
from pydantic import BaseModel
from typing import List, Optional
from ..schemas.research import (
    ResearchQueryRequest, ResearchQueryResponse, SessionStatusResponse,
)
from ..schemas.council import AgentConfig, CouncilConfigRequest, DEFAULT_AGENTS
from ..core.auth import get_current_user
from ..core.firebase import get_db
from ..workers.pipeline import run_research_pipeline
import uuid
from datetime import datetime, timezone


class ChatRequest(BaseModel):
    message: str
    history: Optional[List[dict]] = []


def _snake_to_camel(s: str) -> str:
    parts = s.split("_")
    return parts[0] + "".join(p.capitalize() for p in parts[1:])


def _to_camel(obj):
    """Recursively convert dict keys from snake_case to camelCase."""
    if isinstance(obj, dict):
        return {_snake_to_camel(k): _to_camel(v) for k, v in obj.items()}
    if isinstance(obj, list):
        return [_to_camel(i) for i in obj]
    return obj

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


@router.post("/query", response_model=ResearchQueryResponse)
async def submit_query(
    body: ResearchQueryRequest,
    background_tasks: BackgroundTasks,
    user: dict = Depends(get_current_user),
):
    # Generate session ID and return immediately — no blocking Firestore calls here.
    # The pipeline background task creates the Firestore document as its first action.
    session_id = str(uuid.uuid4())
    print(f"[API] /research/query called — session {session_id[:8]} user {user['uid'][:8]}")
    background_tasks.add_task(run_research_pipeline, session_id, body.query, user["uid"])
    return ResearchQueryResponse(session_id=session_id)


@router.get("/{session_id}/status", response_model=SessionStatusResponse)
async def get_status(
    session_id: str,
    user: dict = Depends(get_current_user),
):
    db  = get_db()
    doc = db.collection("research_sessions").document(session_id).get()
    if not doc.exists:
        raise HTTPException(status_code=404, detail="Session not found")
    data = doc.to_dict()
    if data.get("userId") != user["uid"]:
        raise HTTPException(status_code=403, detail="Forbidden")
    return SessionStatusResponse(
        session_id=session_id,
        status=data["status"],
        paper_count=data.get("paperCount"),
    )


@router.get("/{session_id}/papers")
async def get_papers(session_id: str, user: dict = Depends(get_current_user)):
    db     = get_db()
    docs   = db.collection("papers").where("sessionId", "==", session_id).stream()
    papers = [_to_camel({"id": d.id, **d.to_dict()}) for d in docs]
    return {"papers": papers}


@router.get("/{session_id}/report")
async def get_report(session_id: str, user: dict = Depends(get_current_user)):
    db = get_db()
    # Try snake_case first (Pydantic model_dump default), then camelCase fallback
    docs = list(db.collection("reports").where("session_id", "==", session_id).limit(1).stream())
    if not docs:
        docs = list(db.collection("reports").where("sessionId", "==", session_id).limit(1).stream())
    report = next(({"id": d.id, **d.to_dict()} for d in docs), None)
    if not report:
        raise HTTPException(status_code=404, detail="Report not ready yet")
    return {"report": _to_camel(report)}


@router.post("/{session_id}/regenerate-report")
async def regenerate_report(session_id: str, background_tasks: BackgroundTasks, user: dict = Depends(get_current_user)):
    """Re-run report generation for an existing completed session (fixes static fallback reports)."""
    db  = get_db()
    doc = db.collection("research_sessions").document(session_id).get()
    if not doc.exists:
        raise HTTPException(status_code=404, detail="Session not found")
    data = doc.to_dict()
    if data.get("userId") != user["uid"]:
        raise HTTPException(status_code=403, detail="Forbidden")

    query = data.get("query", "")

    async def _regen():
        from ..services.reporting.report_generator import generate_report
        from ..schemas.research import Paper, PaperExtraction, PaperSource

        # Load papers from Firestore
        paper_docs = db.collection("papers").where("sessionId", "==", session_id).stream()
        papers = []
        for pd in paper_docs:
            raw = pd.to_dict()
            try:
                ext_raw = raw.get("extraction") or {}
                extraction = PaperExtraction(**ext_raw) if ext_raw else None
                papers.append(Paper(
                    id=raw.get("id", pd.id),
                    session_id=session_id,
                    external_source=raw.get("externalSource") or raw.get("external_source") or "arxiv",
                    source_paper_id=raw.get("sourcePaperId") or raw.get("source_paper_id") or "",
                    title=raw.get("title", ""),
                    authors=raw.get("authors", []),
                    year=raw.get("year"),
                    abstract=raw.get("abstract", ""),
                    citation_count=raw.get("citationCount") or raw.get("citation_count"),
                    relevance_score=raw.get("relevanceScore") or raw.get("relevance_score"),
                    extraction=extraction,
                ))
            except Exception as e:
                print(f"[Regen] Skipping paper: {e}")

        print(f"[Regen] Regenerating report for session {session_id[:8]} with {len(papers)} papers")
        report = await generate_report(query, papers, session_id)
        db.collection("reports").document(report.id).set(report.model_dump())
        print(f"[Regen] Report saved: {report.id}")

    background_tasks.add_task(_regen)
    return {"status": "regenerating", "message": "Report is being regenerated. Refresh in ~30 seconds."}


@router.get("/{session_id}/graph")
async def get_graph(session_id: str, user: dict = Depends(get_current_user)):
    db  = get_db()
    doc = db.collection("graphs").document(session_id).get()
    if not doc.exists:
        raise HTTPException(status_code=404, detail="Graph not ready yet")
    return {"graph": doc.to_dict()}


@router.get("/{session_id}/neo4j-graph")
async def get_neo4j_graph(session_id: str, user: dict = Depends(get_current_user)):
    """Returns the knowledge graph directly from Neo4j AuraDB."""
    try:
        from ..services.graph.neo4j_writer import get_graph_for_session
        data = get_graph_for_session(session_id)
        return {"graph": data}
    except RuntimeError as e:
        raise HTTPException(status_code=503, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Neo4j query failed: {e}")


@router.get("/{session_id}/contradictions")
async def get_contradictions(session_id: str, user: dict = Depends(get_current_user)):
    db = get_db()
    # Try snake_case first, then camelCase fallback
    docs = list(db.collection("contradictions").where("session_id", "==", session_id).stream())
    if not docs:
        docs = list(db.collection("contradictions").where("sessionId", "==", session_id).stream())
    return {"contradictions": [_to_camel({"id": d.id, **d.to_dict()}) for d in docs]}


# ── Council endpoints ─────────────────────────────────────────────────────────

@router.get("/{session_id}/council")
async def get_council(session_id: str, user: dict = Depends(get_current_user)):
    db  = get_db()
    doc = db.collection("council_sessions").document(session_id).get()
    if not doc.exists:
        return {
            "council": {
                "session_id": session_id,
                "status":     "idle",
                "agents":     [a.model_dump() for a in DEFAULT_AGENTS],
                "round_1":    [],
                "round_2":    [],
                "round_3":    [],
                "supervisor": None,
            }
        }
    return {"council": doc.to_dict()}


@router.post("/{session_id}/council/configure")
async def configure_council(
    session_id: str,
    body:       CouncilConfigRequest,
    user:       dict = Depends(get_current_user),
):
    db = get_db()
    doc = db.collection("council_sessions").document(session_id).get()
    current = doc.to_dict() if doc.exists else {}
    current_status = current.get("status", "idle")

    if current_status not in ("idle", "configured"):
        raise HTTPException(status_code=409, detail="Council has already started — cannot reconfigure.")

    db.collection("council_sessions").document(session_id).set({
        "session_id": session_id,
        "status":     "configured",
        "agents":     [a.model_dump() for a in body.agents],
        "round_1":    [],
        "round_2":    [],
        "round_3":    [],
        "supervisor": None,
        "created_at": datetime.now(timezone.utc).isoformat(),
    })
    return {"status": "configured", "agents": [a.model_dump() for a in body.agents]}


@router.post("/{session_id}/council/start")
async def start_council(
    session_id:        str,
    background_tasks:  BackgroundTasks,
    user:              dict = Depends(get_current_user),
):
    """Manually trigger the council debate (if user wants to start it before the pipeline reaches that stage)."""
    db  = get_db()
    doc = db.collection("council_sessions").document(session_id).get()
    if not doc.exists:
        raise HTTPException(status_code=404, detail="No council session found. Run the research pipeline first.")

    cd = doc.to_dict()
    if cd.get("status") not in ("idle", "configured"):
        return {"status": cd.get("status"), "message": "Council is already running or complete."}

    # Load papers for this session
    paper_docs = db.collection("papers").where("sessionId", "==", session_id).stream()
    from ..schemas.research import Paper, PaperExtraction
    papers = []
    for pd in paper_docs:
        raw = pd.to_dict()
        try:
            ext_raw    = raw.get("extraction") or {}
            extraction = PaperExtraction(**ext_raw) if ext_raw else None
            papers.append(Paper(
                id=raw.get("id", pd.id),
                session_id=session_id,
                external_source=raw.get("externalSource") or raw.get("external_source") or "arxiv",
                source_paper_id=raw.get("sourcePaperId") or raw.get("source_paper_id") or "",
                title=raw.get("title", ""),
                authors=raw.get("authors", []),
                year=raw.get("year"),
                abstract=raw.get("abstract", ""),
                citation_count=raw.get("citationCount") or raw.get("citation_count"),
                relevance_score=raw.get("relevanceScore") or raw.get("relevance_score"),
                extraction=extraction,
            ))
        except Exception as e:
            print(f"[Council start] Skipping paper: {e}")

    agents = [AgentConfig(**a) for a in cd.get("agents", [])] or DEFAULT_AGENTS
    session_doc = db.collection("research_sessions").document(session_id).get()
    query = (session_doc.to_dict() or {}).get("query", "")

    from ..core.config import get_settings
    from ..services.council.council_runner import run_debate_council

    settings = get_settings()

    async def _run_council():
        await run_debate_council(session_id, query, papers, agents, db, num_rounds=settings.council_rounds)

    background_tasks.add_task(_run_council)
    return {"status": "started", "message": "Council debate is running in the background."}


# ── Chat endpoints ────────────────────────────────────────────────────────────

@router.get("/{session_id}/chat")
async def get_chat_history(session_id: str, user: dict = Depends(get_current_user)):
    db   = get_db()
    docs = (
        db.collection("chat_messages")
        .where("session_id", "==", session_id)
        .order_by("created_at")
        .stream()
    )
    messages = [{"id": d.id, **d.to_dict()} for d in docs]
    return {"messages": messages}


@router.post("/{session_id}/chat")
async def send_chat_message(
    session_id: str,
    body:       ChatRequest,
    user:       dict = Depends(get_current_user),
):
    from ..services.chat.chat_agent import answer_research_question

    db = get_db()

    # Load all papers for this session
    paper_docs = db.collection("papers").where("sessionId", "==", session_id).stream()
    papers = []
    for pd in paper_docs:
        raw = pd.to_dict()
        papers.append(raw)

    if not papers:
        return {"answer": "No papers found for this session yet. Please wait for the pipeline to complete."}

    try:
        answer = await answer_research_question(
            question=body.message,
            papers=papers,
            history=body.history or [],
        )
    except Exception as e:
        print(f"[Chat] Error: {e}")
        answer = f"An error occurred while processing your question: {e}"

    # Persist conversation turns
    now = datetime.now(timezone.utc).isoformat()
    try:
        db.collection("chat_messages").document(str(uuid.uuid4())).set({
            "session_id": session_id,
            "role":       "user",
            "content":    body.message,
            "created_at": now,
        })
        db.collection("chat_messages").document(str(uuid.uuid4())).set({
            "session_id": session_id,
            "role":       "assistant",
            "content":    answer,
            "created_at": now,
        })
    except Exception as e:
        print(f"[Chat] Could not persist message: {e}")

    return {"answer": answer}