import React, { useEffect, useRef, useState } from "react";

import { Alert, Box, Button, TextField, Typography } from "@mui/material";

import { useNavigate } from "react-router-dom";

import { api, getApiErrorMessage } from "../api";
import { useToast } from "../toast";
import { useI18n } from "../i18n/I18nProvider";
import AuthPageFrame from "../layout/AuthPageFrame";

export default function ForgotPasswordPage() {
  const { toast } = useToast();
  const { t } = useI18n();
  const navigate = useNavigate();

  const [email, setEmail] = useState("");
  const [loading, setLoading] = useState(false);
  const [submitted, setSubmitted] = useState(false);
  const [emailError, setEmailError] = useState<string | undefined>(undefined);
  const [submitError, setSubmitError] = useState<string | null>(null);
  const emailRef = useRef<HTMLInputElement>(null);
  const EMAIL_PATTERN = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;

  useEffect(() => {
    const params = new URLSearchParams(window.location.search);
    setEmail(params.get("email") || "");
  }, []);

  return (
    <AuthPageFrame title={t("forgotPasswordTitle")} description={t("forgotPasswordBody")}>
        <Box
          component="form"
          onSubmit={(e) => {
            e.preventDefault();
            const trimmed = email.trim();
            if (!trimmed) {
              setEmailError(t("emailRequired"));
              emailRef.current?.focus();
              return;
            }
            if (!EMAIL_PATTERN.test(trimmed)) {
              setEmailError(t("invalidEmail"));
              emailRef.current?.focus();
              return;
            }
            setEmailError(undefined);
            setSubmitError(null);
            setSubmitted(false);
            setLoading(true);
            api
              .post("/auth/request-password-reset", { email: email.trim() })
              .then(() => {
                setSubmitted(true);
                toast(t("passwordResetRequestSent"), "success");
              })
              .catch((error: any) => {
                setSubmitError(getApiErrorMessage(error, t("passwordResetRequestFailed")));
              })
              .finally(() => setLoading(false));
          }}
          sx={{ display: "flex", flexDirection: "column", gap: 1.5 }}
        >
          {submitted ? <Alert severity="success" role="status">{t("passwordResetRequestSent")}</Alert> : null}
          {submitError ? <Alert severity="error">{submitError}</Alert> : null}
          <TextField
            label={t("profileEmail")}
            type="email"
            value={email}
            onChange={(e) => { setEmail(e.target.value); setEmailError(undefined); }}
            autoComplete="email"
            autoFocus
            inputRef={emailRef}
            error={Boolean(emailError)}
            helperText={emailError}
            fullWidth
          />

          <Box sx={{ display: "flex", flexWrap: "wrap", justifyContent: "flex-end", gap: 1, mt: 1, "& > button": { maxWidth: "100%", whiteSpace: "normal", overflowWrap: "anywhere" } }}>
            <Button type="button" variant="outlined" onClick={() => navigate("/login")} disabled={loading}>
              {t("backToLogin")}
            </Button>
            <Button type="submit" variant="contained" disabled={loading} aria-busy={loading}>
              {t("forgotPasswordSubmit")}
            </Button>
          </Box>
          {loading ? <Typography role="status" aria-live="polite" variant="body2" color="text.secondary">{t("passwordResetRequestSending")}</Typography> : null}
        </Box>
    </AuthPageFrame>
  );
}