from typing import Tuple, Dict

from sqlalchemy.orm import sessionmaker
from sqlalchemy import Engine, text, update

from s3 import s3helper
from db import pgclass

class DB:
    _engine = None

    @classmethod
    def __init__(cls, engine):
        cls._engine:Engine = engine

    @classmethod
    def getsession(cls):
        Session = sessionmaker(bind=cls._engine)
        return Session()

db:DB = None


# role (general) (owner) (admin)
# 獲取單一文章
def solo_article_fetcher(role:str, key:int, hash:str=None) -> Tuple[Dict, int]: # admin, owner, general
    with db.getsession() as session:
        # article fetch
        stmt="SELECT posts.id, posts.content, posts.file_list, meta.igid, posts.hash, meta.ip, pmark.mark " \
            +"FROM posts " \
            +"INNER JOIN mark AS pmark ON posts.hash=pmark.hash " \
            +"INNER JOIN article_meta AS meta ON posts.hash=meta.hash "
        if role == "owner": # 驗證id/hash，可以看到本體(無驗證)
            stmt += "WHERE posts.id = :id AND posts.hash = :hash"
        elif role == "admin": # 驗證id，可以看到本體(無驗證)
            stmt += "WHERE posts.id = :id"
        elif role == "general": # 驗證id，可以看到本體(visible)
            stmt += "WHERE posts.id=:id AND pmark.mark='visible'"
        result = session.execute(text(stmt), {"id":key, "hash":hash})
        res = result.first()
        if res is None: 
            return {}, 404
        
        # comment fetch
        stmt="SELECT c.sha1 " \
            +"FROM posts " \
            +"INNER JOIN unnest(posts.comment_list) AS c ON c=ANY(posts.comment_list) " \
            +"INNER JOIN mark AS cmark ON c.hash=cmark.hash " \
            +"WHERE posts.id=:id"
        if role == "general": # 留言sha1(visible)
            stmt+=" AND cmark.mark='visible'"
        result = session.execute(text(stmt), {"id":res[0]})
        cres = result.all()

        # mapping
        one = {
            "id": res[0],
            "content": res[1],
            "igid": res[3],
        }
        if res[2]: # files
            one["files_hash"] = res[2]
        if res[4]: # comments
            one["comments_hash"] = [ c[0] for c in cres ]
        
        if role == "admin": 
            one["ip"] = res[5]
            one["mark"] = res[6]
            one["hash"] = res[4]
        
    return one, 200


# role (general) (owner) (admin)
# 獲取單一留言 - 可能不會用到
def solo_comment_fetcher(role:str, key:str, hash:str=None) -> Tuple[Dict, int]: # admin, owner, general
    with db.getsession() as session:
        # query
        stmt="SELECT posts.id AS parent_id, posts.hash AS parent_hash, pmark.mark AS parent_mark, cmark.mark AS comment_mark, c.* " \
            +"FROM posts " \
            +"INNER JOIN unnest(posts.comment_list) AS c ON c=ANY(posts.comment_list) " \
            +"JOIN mark AS pmark ON posts.hash=pmark.hash " \
            +"JOIN mark AS cmark ON c.hash=cmark.hash " \
            +"WHERE c.sha1=:sha1 "
        if role == "general":
            # 對一般用戶，sha1查詢，確保本體跟留言可見
            stmt += "AND pmark.mark='visible' AND cmark.mark='visible'"
            arta = session.execute(text(stmt), {'sha1':key}).first()
        elif role == "owner":
            # 對發文者，sha1查詢，sha256查詢，不設檢查
            stmt += "AND c.hash=:hash"
            arta = session.execute(text(stmt), {'sha1':key, 'hash':hash}).first()
        elif role == "admin":
            # 對管理員，sha1查詢，不設檢查
            arta = session.execute(text(stmt), {'sha1':key}).first()
        if arta is None:
            return {}, 404

        # mapping
        one = {
            "content": arta[4],
            "sha1": arta[8]
        }
        
        if role == "admin": 
            one["ip"] = arta[5]
            one["mark"] = arta[3]
            one["hash"] = arta[6]
        
    return one, 200


# 獲取檔案 - for IG
def solo_file_fetcher(role:str, fnhash:str) -> Tuple[dict, int]: # general, admin
    with db.getsession() as session:
        arta="SELECT posts.id FROM posts " \
            +"INNER JOIN mark ON posts.hash=mark.hash " \
            +"WHERE :fnhash=ANY (posts.file_list) "
        if role == "general":
            arta += "AND mark.mark = 'visible'"
        arta = session.execute(text(arta), {'fnhash':fnhash}).first()
        if arta is None: # 檢查文章本體是否存在/可以閱覽
            return {}, 404
    
    # fetch file
    f, err = s3helper.solo_file_fetcher(fnhash)
    if err:
        return {}, 404
    return f, 200


# 填入 igid
def solo_article_set_igid(id:int, igid:str) -> int:
    # get hash
    article, code = solo_article_fetcher(role="admin", key=id)
    if code != 200:
        return 1
    hash = article["hash"]
    # print(hash)
    
    # edit igid
    err = 0
    article_meta = pgclass.SQLmeta
    with db.getsession() as session:
        try:
            stmt = update(article_meta).where(article_meta.hash==hash).values(igid=igid)
            session.execute(stmt)
        except Exception as e:
            err = 1
        session.commit()
    return err