# coding=utf-8
import csv
import json
import time
import sys
import os

sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
import random
import traceback
from selenium.webdriver.common.by import By
from selenium.webdriver.support.select import Select
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.common.exceptions import (
    TimeoutException, NoSuchElementException,
)
from selenium.webdriver.common.action_chains import ActionChains
from config import create_browser,_scroll_into_view
# ---------主函数 ---------
def extract_row_info(row, driver):
    """抓取单条记录信息并返回字典"""
    try:
        url_elem = row.find_element(By.CSS_SELECTOR, "a.docsum-title")
        title = url_elem.text.strip()
        originalLink = url_elem.get_attribute("href")
    except Exception as e:
        title = ""
        originalLink = ""
        print("[错误] 获取论文标题或链接失败:", e)
    #抓取作者以及引用信息
    try:
        authors = row.find_element(By.XPATH,
                                   ".//span[contains(@class,'docsum-authors') and contains(@class,'full-authors')]").text
        citation = row.find_element(By.XPATH,
                                    ".//span[contains(@class,'docsum-journal-citation') and contains(@class,'full-journal-citation')]").text
    except:
        citation = ""
        authors =  ""
    print("论文原处:",originalLink)
    print("论文标题:", title)
    print("作者列表:", authors)
    print("论文引用:", citation)

    try:
        downloadElem = row.find_element(By.XPATH,".//div[contains(@class,'docsum-citation') and contains(@class,'full-citation')]")
        downloadText = downloadElem.text
    except:
        downloadText = ""
    time.sleep(1)
    url_elem.click()
    time.sleep(3)  # 等待加载
    # 摘要
    try:
        abstract_elem = driver.find_element(By.CSS_SELECTOR, "#eng-abstract p")
        abstract_text = abstract_elem.text.strip()
    except NoSuchElementException:
        abstract_text = ""
    print("摘要：", abstract_text)
    # 关键词（可能没有）
    try:
        keyword_elem = driver.find_element(By.CSS_SELECTOR, "#abstract > p")
        keyword_text = keyword_elem.text.replace("Keywords:", "").strip()
    except NoSuchElementException:
        keyword_text = ""
    print("关键词：", keyword_text)
    pdf_url = ""
    if "Free PMC article" in downloadText:
        print("✅ 该文章是免费文章，可以下载")
        original_handle = driver.current_window_handle
        original_handles = driver.window_handles.copy()

        # --- 点击下载按钮 ---
        print("[步骤] 跳转下载界面 ...")

        try:
            pdf_selector = WebDriverWait(driver, 5).until(
                EC.presence_of_element_located(
                    (By.XPATH, "//a[contains(@class,'link-item') and contains(@class,'pmc')]"))
            )
        except Exception:
            print("❌ 找不到 PMC PDF 链接，跳过下载")
            pdf_selector = None
        if pdf_selector:

            try:
                pdf_selector.click()
            except Exception:
                driver.execute_script("arguments[0].click();", pdf_selector)
            print("[步骤] 点击完成，等待新窗口/页面...")

            # --- 判断是否有新窗口 ---
            try:
                WebDriverWait(driver, 5).until(lambda d: len(d.window_handles) > len(original_handles))
                new_handle = [h for h in driver.window_handles if h not in original_handles][0]
                driver.switch_to.window(new_handle)
                print("[步骤] 已切换到新窗口:", new_handle)
            except TimeoutException:
                print("[步骤] 没有新窗口，在当前窗口继续处理。")

            time.sleep(1)

            # --- 切换后重新查找 PDF 元素 ---
            try:
                print("[步骤] 等待 PDF 按钮出现...")
                pdf_a = WebDriverWait(driver, 10).until(
                    EC.presence_of_element_located(
                        (By.XPATH, "//a[contains(@class,'usa-button') and contains(@href,'pdf/')]")
                    )
                )
                pdf_url = pdf_a.get_attribute("href")
                if pdf_url:
                    print("📄 PDF 链接:", pdf_url)

            except Exception as e:
                print("❌ 获取 PDF 失败:", e)

            finally:
                # --- 关闭并切回原窗口 ---
                current = driver.current_window_handle
                if current != original_handle:
                    driver.close()
                    driver.switch_to.window(original_handle)
                    time.sleep(1)
                    print("[步骤] 已切回原窗口。")

    else:
        print("❌ 该文章不是免费文章")

    # 回退到上一级
    driver.back()
    time.sleep(2)  # 等待页面加载完成

    return {
        "title": title,  # 确保函数里有定义
        "author": authors,
        "site":"pubmed",
        "originalLink":originalLink,
        "citation": citation,
        "pdfUrl": pdf_url,
        "keywords": keyword_text,
        "summary": abstract_text
    }
def crawl_current_sort(driver, limit):
    """抓取当前排序下的 limit 条记录"""
    fetched_count = 0
    results = []

    while fetched_count < limit:
        try:
            WebDriverWait(driver, 10).until(
                EC.presence_of_element_located((By.CSS_SELECTOR, '#search-form > div.inner-wrap > a.pubmed-logo > img'))
            )
        except TimeoutException:
            print("[警告] 本页结果表格未出现，尝试继续")
        time.sleep(2)

        rows = driver.find_elements(By.XPATH, '//*[@id="search-results"]/section/div[2]/div/article')

        for row in rows:
            if fetched_count >= limit:
                break
            try:
                info = extract_row_info(row, driver)
                if info:  # 只有 info 有效才追加
                    results.append(info)
                    fetched_count += 1
                    time.sleep(2)
            except Exception as e:
                print(f"[错误] 抓取 row 失败: {e}")
                traceback.print_exc()
                # 如果窗口还存在，强制切回主窗口，避免死锁
                try:
                    if driver.window_handles:
                        driver.switch_to.window(driver.window_handles[0])
                except Exception:
                    pass
                continue  # 遇错后继续下一个 row，不要影响整体

        # 翻页
        try:
            next_btn = driver.find_element(By.CSS_SELECTOR,"#search-results > div.top-wrapper > div.top-pagination > button.button-wrapper.next-page-btn > img.chevron-icon.enabled-icon")
            if next_btn.is_enabled() and fetched_count < limit:
                _scroll_into_view(driver, next_btn)
                try:
                    next_btn.click()
                except Exception:
                    try:
                        ActionChains(driver).move_to_element(next_btn).pause(0.1).click(next_btn).perform()
                    except Exception:
                        driver.execute_script("arguments[0].click();", next_btn)
                time.sleep(random.uniform(1, 2))
            else:
                break
        except NoSuchElementException:
            print("[INFO] 已到最后一页或翻页不存在")
            break
        except Exception as e:
            print(f"[错误] 翻页失败: {e}")
            break

    return results
def pubmed(keyword, limit,sort_options=None):
    """主函数：三种排序抓取"""
    driver = create_browser()
    wait = WebDriverWait(driver, 15)
    all_results = {}
    if not sort_options:
        sort_options = ["relevance"]  # 默认相关性

    try:
        driver.get("https://pubmed.ncbi.nlm.nih.gov/")
        wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, "#id_term"))).send_keys(keyword)
        time.sleep(1)
        driver.find_element(By.CSS_SELECTOR, "#search-form > div > div.search-input > div > button").click()
        time.sleep(4)
        for sort_name in sort_options:
            try:
                if sort_name == "publication_time":
                    print("[INFO] 使用时间进行排序")
                    # 等待下拉框出现
                    sort_elem = driver.find_element(By.ID, "id_sort")
                    sort_select = Select(sort_elem)
                    sort_select.select_by_value("pubdate")  # 或 select_by_visible_text("Publication date")
                    time.sleep(2)
                elif sort_name == "relevance":
                    print("[INFO] 使用相关性排序（默认）")

            except Exception as e:
                print(f"[WARN] 点击排序 {sort_name} 失败:", e)

            # 抓取当前排序下的结果
            results = crawl_current_sort(driver, limit)
            all_results[sort_name] = results

    finally:
        try:
            driver.quit()
        except Exception:
            pass
        print("[DONE] PDF处理完成")
    print(json.dumps(all_results, ensure_ascii=False, indent=2))

    return all_results

if __name__ == '__main__':
    keyword = "bert"
    limit=100
    # pubmed(keyword, limit, ["relevance"])
    # 搜最新
    # pubmed(keyword, limit, ["publication_time"])
    # 先相关性再最新
    pubmed(keyword, limit, ["relevance", "publication_time"])