import os

from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer

import aops
import bon

envs = {
    "problem": ("\\begin{problem}", "\\end{problem}"),
    "solution": ("\\begin{soln}", "\\end{soln}"),
}

WATCH_FILE = os.path.join(bon.TMP_PATH, bon.TMP_FILE_NAME)
OUTPUT_FILE = os.path.join(bon.HOME, "bon/bon-db/", f"{bon.DB_NAME}{bon.DB_FILE_EXT}")


# class TexChangeHandler(FileSystemEventHandler):
#     def on_modified(self, event):
#         log(f"Modified: {event.src_path}")
#         if os.path.abspath(event.src_path) == os.path.abspath(WATCH_FILE):
#             log("Ignored: Not the target file.")
#             with open(WATCH_FILE, "r", encoding="utf-8") as f:
#                 tex_content = f.read()
#             with open(OUTPUT_FILE, "r", encoding="utf-8") as f:
#                 db_content = f.read()
#             with open(OUTPUT_FILE, "w", encoding="utf-8") as out:
#                 out.write(transform(db_content, tex_content))
#             print("yes")
#
class TexChangeHandler(FileSystemEventHandler):
    def on_modified(self, event):
        log(f"🔔 Modified: {event.src_path}")

        if os.path.abspath(event.src_path) != os.path.abspath(WATCH_FILE):
            log("❌ Ignored: Not the target file.")
            return

        try:
            with open(WATCH_FILE, "r", encoding="utf-8") as f:
                tex_content = f.read()
            with open(OUTPUT_FILE, "r", encoding="utf-8") as f:
                db_content = f.read()
            updated = transform(db_content, tex_content)
            with open(OUTPUT_FILE, "w", encoding="utf-8") as out:
                out.write(updated)
            log("✅ Wrote updated content to DB file.")
        except Exception as e:
            log(f"❌ ERROR: {e}")


def transform(db_content: str, tex_content: str) -> str:
    fin_list = []
    db_list = db_content.split(bon.SEPARATOR)
    prob_spos = tex_content.index(envs["problem"][0])
    prob_epos = tex_content.index(envs["problem"][1])
    prob_cont = tex_content[prob_spos : prob_epos + len(envs["problem"][1])]
    fin_list.append(db_list[0])
    fin_list.append(prob_cont)
    i = 0
    while tex_content[i:].find(envs["solution"][0]) != -1:
        j = tex_content[i:].index(envs["solution"][0])
        j_cpos = aops.bracket_cpos(tex_content[i:], envs["solution"], j)
        fin_list.append(tex_content[j : j_cpos + len(envs["solution"][1])])
        i = j_cpos
    return (bon.SEPARATOR).join(fin_list)


def start_watcher():
    log("Watcher started")
    event_handler = TexChangeHandler()
    observer = Observer()
    observer.schedule(event_handler, path=os.path.dirname(WATCH_FILE), recursive=False)
    observer.start()
    log("Watcher actually started")
    return observer


def log(msg):
    with open("/tmp/tmptex_watcher.log", "a", encoding="utf-8") as f:
        f.write(msg + "\n")