import asyncio
from contextlib import asynccontextmanager
import logging
from typing import Literal, Optional
from fastapi import FastAPI, APIRouter
from httpx import AsyncClient
from pydantic import BaseModel, Field
import uvicorn
from playwright.async_api import async_playwright, Browser

from scrap.base import ScrapperBackendBase
from scrap.gpatents import GpatentsScrapBackend
from serp.base import SERPBackendBase, SerpQuery, SerpResultItem, get_backends_doc, query_serp_backend
from serp.arxiv import ArxivSerpBackend
from serp.bing import BingSerpBackend
from serp.duckduckgo import DuckDuckGoSerpBackend
from serp.gpatents import GPatentsSerpBackend


logging.basicConfig(
    level=logging.INFO,
    format='[%(asctime)s][%(levelname)s][%(filename)s:%(lineno)d]: %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S'
)

# playwright global context
playwright = None
pw_browser: Optional[Browser] = None

# HttpX client
http_client = AsyncClient()


@asynccontextmanager
async def api_lifespan(app: FastAPI):
    """Lifespan context manager for FastAPI to manage Playwright browser instance."""
    global playwright, pw_browser
    playwright = await async_playwright().start()
    pw_browser = await playwright.chromium.launch(headless=True)

    yield

    await pw_browser.close()
    await playwright.stop()

app = FastAPI(lifespan=api_lifespan, docs_url="/")
serp_router = APIRouter(prefix="/serp", tags=["SERP"])
scrap_router = APIRouter(prefix="/scrap", tags=["scrapping"])

# All backends for SERP scrapping
SERP_BACKENDS = {b.name: b for b in [DuckDuckGoSerpBackend(),
                                     BingSerpBackend(),
                                     ArxivSerpBackend(),
                                     GPatentsSerpBackend()]}

# All backends for scrap scrapping
SCRAP_BACKENDS = {b.content_type: b for b in [
    GpatentsScrapBackend()
]}

app.description = get_backends_doc(SERP_BACKENDS.values())


# ======================== Request schemas for SERP search ================================

class SerpRequest(BaseModel):
    """Model for a single-query SERP search"""
    query: SerpQuery = Field(..., description="The query to perform")
    backend: str = Field(..., description="The backend to use for search.")


class SerpResponse(BaseModel):
    """Model for single-query SERP search results"""
    error: Optional[str]
    backend: Optional[str]
    results: Optional[list[SerpResultItem]] = Field(
        None, description="List of search results for the query")


class SerpBulkRequest(BaseModel):
    """A bulk request with many queries"""
    queries: list[SerpQuery] = Field(...,
                                     description="Lists of queries to perform")
    backend: str = Field(...,
                         description="The backend to use for the bulk search.")


class SerpBulkResultItem(BaseModel):
    """Intermediate result item for bulk results"""
    query: str
    error: Optional[str]
    backend: Optional[str]
    results: Optional[list[SerpResultItem]]

    @classmethod
    def from_err(cls, q: SerpQuery, err: Exception, backend: str):
        return SerpBulkResultItem(query=q.query, error=str(err), results=None, backend=backend)

    @classmethod
    def from_results(cls, q: SerpQuery, results: list[SerpResultItem], backend: str):
        return SerpBulkResultItem(query=q.query, error=None, results=results, backend=backend)


class SerpBulkResponse(BaseModel):
    """Response to a bulk query"""
    queries: list[SerpBulkResultItem]


class SerpAutoSearchRequest(BaseModel):
    query: SerpQuery
    category: Literal["general", "patent", "scholar"] = "general"


class SerpAutoBulkSearchRequest(BaseModel):
    """A auto-bulk request with many queries"""
    queries: list[SerpQuery]
    category: Literal["general", "patent", "scholar"] = "general"

# =============================================== SERP routes ============================================


@serp_router.post("/search")
async def search(req: SerpRequest) -> SerpResponse:
    """Performs a single SERP search against the given backend with the given query."""

    # Find the backend with the given name
    backend: SERPBackendBase = SERP_BACKENDS.get(req.backend)

    if backend:
        try:
            results = await query_serp_backend(backend, req.query, http_client, pw_browser)
            return SerpResponse(error=None, results=results, backend=backend.name)
        except Exception as e:
            logging.warning(f"Error while querying {backend.name}", e)
            return SerpResponse(error=str(e), results=[], backend=backend.name)

    return SerpResponse(error="No backend with the given backend name was found.", backend=req.backend, results=None)


@serp_router.post("/search/bulk")
async def search_bulk(req: SerpBulkRequest) -> SerpBulkResponse:
    """Performs a bulk SERP search against the given backend with the given queries."""

    # Find the backend with the given name
    backend: SERPBackendBase = SERP_BACKENDS.get(req.backend)

    if backend:
        logging.info(
            f"Bulk querying {backend.name} with queries: {req.queries}")

        results = await asyncio.gather(*[query_serp_backend(backend, q, http_client, pw_browser) for q in req.queries], return_exceptions=True)

        for r in results:
            if isinstance(r, Exception):
                logging.warning(
                    f"Exception occured while querying {backend.name}", r)

        result_sections = [SerpBulkResultItem.from_err(q, r, backend.name)
                           if isinstance(r, Exception) else SerpBulkResultItem.from_results(q, r, backend.name) for r, q in zip(results, req.queries)]

        return SerpBulkResponse(queries=result_sections)

    return SerpResponse(error="No backend with the given backend name was found.", backend=req.backend, results=None)


@serp_router.post("/fallback_search")
async def search_fallback(auto: SerpAutoSearchRequest) -> SerpResponse:
    """Searches the given query with the first usable backend that matches the requested content category and fallbacks to the next one if it fails"""

    logging.info(f"Auto-search with query {auto}")
    for backend in SERP_BACKENDS.values():
        if backend.category.lower() != auto.category.lower():
            continue

        try:
            results = await query_serp_backend(backend, auto.query, http_client, pw_browser)
            return SerpResponse(error=None, results=results, backend=backend.name)
        except Exception as e:
            logging.warning(f"Search with {backend.name} backend failed: {e}")
            logging.info("Trying out query with next available backend.")
            continue

    return SerpResponse(error="No adequate backend found or all backends are rate-limited", results=None, backend=None)


@serp_router.post("/fallback_search/bulk")
async def search_fallback_bulk(auto: SerpAutoBulkSearchRequest) -> SerpBulkResponse:
    """Bulk searches the given queries with the first usable backend that matches the requested content category and fallbacks to the next one if it fails"""

    logging.info(f"Bulk Auto-search with query {auto}")

    async def _process_q(q: SerpQuery):
        for backend in SERP_BACKENDS.values():
            if backend.category.lower() != auto.category.lower():
                continue

            try:
                results = await query_serp_backend(backend, q, http_client, pw_browser)
                return (results, backend)
            except Exception as e:
                logging.warning(
                    f"Search with {backend.name} backend failed: {e}")
                continue

        raise Exception(
            error="No adequate backend found or all backends are rate-limited")

    tasks = await asyncio.gather(*[_process_q(q) for q in auto.queries], return_exceptions=True)
    result_sections = [SerpBulkResultItem.from_err(q, r[0], "") if isinstance(
        r[0], Exception) else SerpBulkResultItem.from_results(q, r[0], r[1].name) for r, q in zip(tasks, auto.queries)]

    return SerpBulkResponse(queries=result_sections)

# =============================================== scrapping routes ============================================


class FetchContentResponse(BaseModel):
    error: Optional[str]
    backend: Optional[str]
    content: Optional[dict]


@scrap_router.get("/full_contents")
async def full_content(slug: str) -> FetchContentResponse:
    splitted_slug = slug.split(":", 1)
    content_type = splitted_slug[0]
    content_id = splitted_slug[1]

    backend: ScrapperBackendBase = SCRAP_BACKENDS.get(content_type)

    if backend:
        try:
            result = await backend.scrap(http_client, content_id)
            return FetchContentResponse(error=None, backend=backend.content_type, content=result.model_dump())
        except Exception as e:
            return FetchContentResponse(error=str(e), backend=backend.content_type, content=None)

    return FetchContentResponse(error="No backend supporting found", backend="", content=None)


@scrap_router.get("/fetch_content")
async def fetch_content(back: str, id: str) -> FetchContentResponse:
    backend: ScrapperBackendBase = SCRAP_BACKENDS.get(back)

    if backend:
        try:
            result = await backend.scrap(http_client, id)
            return FetchContentResponse(error=None, backend=back, content=result.model_dump())
        except Exception as e:
            return FetchContentResponse(error=str(e), backend=back, content=None)

    return FetchContentResponse(error="No backend found", backend=back, content=None)


app.include_router(serp_router)
app.include_router(scrap_router)

uvicorn.run(app, host="0.0.0.0", port=7860)