from __future__ import annotations

import re
import tkinter as tk
from decimal import Decimal, InvalidOperation
from pathlib import Path
from tkinter import messagebox, ttk

from copienator import EvaluationWorkspace, atomic_update_json, read_json
from copienator.utils import natural_key
from .giving_names import RETURN_FOLDER_PATTERN


def score_path_for_id(evaluation: Path, copy_id: str) -> Path:
    identifier = copy_id.strip()
    if not re.fullmatch(r"[0-9]+", identifier):
        raise ValueError("Saisissez un numéro d’id.")
    return_dir = EvaluationWorkspace(evaluation).return_dir
    matches = []
    if return_dir.is_dir():
        for folder in return_dir.iterdir():
            match = RETURN_FOLDER_PATTERN.fullmatch(folder.name)
            if folder.is_dir() and not folder.is_symlink() and match and int(match["copy_id"]) == int(identifier):
                matches.append(folder / "score.json")
    if not matches:
        raise FileNotFoundError(f"Aucun dossier dans A Rendre pour l’id {identifier}.")
    if len(matches) > 1:
        raise ValueError(f"Plusieurs dossiers dans A Rendre portent l’id {identifier}.")
    if not matches[0].is_file():
        raise FileNotFoundError(f"score.json introuvable : {matches[0]}")
    return matches[0]


def read_scores(path: Path) -> dict:
    scores = read_json(path)
    if not isinstance(scores, dict):
        raise ValueError(f"score.json doit contenir un objet JSON : {path}")
    return scores


def set_score(path: Path, label: str, value: str) -> str:
    try:
        number = Decimal(value.strip().replace(",", "."))
    except InvalidOperation:
        raise ValueError("Le score doit être un nombre.") from None
    if not number.is_finite() or number < 0:
        raise ValueError("Le score doit être un nombre positif ou nul.")
    previous = ""

    def update(scores):
        nonlocal previous
        if not isinstance(scores, dict) or label not in scores:
            raise ValueError(f"Label absent de score.json : {label}")
        previous = str(scores[label])
        scores[label] = str(number)

    # A Rendre/score.json is often a symlink to the annotation score file.
    # Resolve it before atomic replacement so the link continues to work.
    atomic_update_json(path.resolve(strict=True), update, default_factory=dict)
    return previous


class ScoreEditorPanel(ttk.Frame):
    def __init__(self, parent, evaluation: Path, on_change):
        super().__init__(parent)
        self.evaluation = evaluation
        self.on_change = on_change
        self.current_path = None
        self.busy = False
        self.id_var = tk.StringVar()
        self.label_var = tk.StringVar()
        self.score_var = tk.StringVar()
        self.status_var = tk.StringVar()
        self.columnconfigure(1, weight=1)
        ttk.Label(self, text="Id de copie").grid(row=0, column=0, sticky="w", padx=(0, 8), pady=4)
        self.id_entry = ttk.Entry(self, textvariable=self.id_var)
        self.id_entry.grid(row=0, column=1, sticky="ew", pady=4)
        ttk.Label(self, text="Label").grid(row=1, column=0, sticky="w", padx=(0, 8), pady=4)
        self.label_entry = ttk.Combobox(self, textvariable=self.label_var)
        self.label_entry.grid(row=1, column=1, sticky="ew", pady=4)
        ttk.Label(self, text="Score").grid(row=2, column=0, sticky="w", padx=(0, 8), pady=4)
        self.score_entry = ttk.Entry(self, textvariable=self.score_var)
        self.score_entry.grid(row=2, column=1, sticky="ew", pady=4)
        self.set_button = ttk.Button(self, text="Set", command=self.save_score)
        self.set_button.grid(row=2, column=2, padx=(8, 0), pady=4)
        ttk.Label(self, textvariable=self.status_var, wraplength=650).grid(
            row=3, column=0, columnspan=3, sticky="w", pady=8
        )
        self.id_var.trace_add("write", self.load_score)
        self.label_var.trace_add("write", self.load_score)
        self.score_entry.bind("<Return>", lambda _event: self.save_score())
        self.load_score()

    def load_score(self, *_args):
        self.current_path = None
        self.score_var.set("")
        self.label_entry.configure(values=())
        try:
            path = score_path_for_id(self.evaluation, self.id_var.get())
            scores = read_scores(path)
            self.label_entry.configure(values=sorted(scores, key=natural_key))
            label = self.label_var.get().strip()
            if not label:
                self.status_var.set("Choisissez ou saisissez un label.")
            elif label not in scores:
                self.status_var.set(f"Label absent de score.json : {label}")
            else:
                self.current_path = path
                self.score_var.set(str(scores[label]))
                self.status_var.set(path.parent.name)
        except (OSError, ValueError) as exc:
            self.status_var.set(str(exc))
        self.set_busy(self.busy)

    def set_busy(self, busy: bool):
        self.busy = busy
        self.id_entry.configure(state="disabled" if busy else "normal")
        self.label_entry.configure(state="disabled" if busy else "normal")
        state = "normal" if self.current_path is not None and not busy else "disabled"
        self.score_entry.configure(state=state)
        self.set_button.configure(state=state)

    def save_score(self):
        if self.current_path is None or self.busy:
            return
        label = self.label_var.get().strip()
        try:
            previous = set_score(self.current_path, label, self.score_var.get())
            current = str(read_scores(self.current_path)[label])
            self.score_var.set(current)
            if previous != current:
                self.on_change(self.id_var.get().strip(), label, previous, current)
            self.status_var.set(f"Score enregistré : {self.current_path.parent.name} — {label} : {current}")
        except (OSError, ValueError) as exc:
            messagebox.showerror("Modification du score", str(exc))