import { useEffect } from "react";
import { Controller, useForm, useWatch } from "react-hook-form";
import { zodResolver } from "@hookform/resolvers/zod";
import { useNavigate, useParams, useSearchParams } from "react-router";
import {
  Alert,
  Box,
  Button,
  Checkbox,
  CircularProgress,
  FormControl,
  FormControlLabel,
  InputLabel,
  MenuItem,
  Paper,
  Select,
  Stack,
  TextField,
  Typography,
} from "@mui/material";
import {
  CALENDAR_REMINDER_OPTIONS,
  CALENDAR_TIME_OPTIONS,
} from "@/components/common/calendar/calendar-utils";
import {
  calendarEventSchema,
  type CalendarEventFormValues,
} from "@/domain/calendar/schemas/calendar-event-schema";
import { useCalendarEventDetail } from "@/domain/calendar/use-cases/use-calendar-event-detail";
import { useCreateCalendarEvent } from "@/domain/calendar/use-cases/use-create-calendar-event";
import { useUpdateCalendarEvent } from "@/domain/calendar/use-cases/use-update-calendar-event";
import { toDateInputValue } from "@/lib/time-utils";

const COLORS = ["primary", "success", "info", "warning", "danger"] as const;

const defaultValues: CalendarEventFormValues = {
  title: "",
  description: "",
  location: "",
  recordId: null,
  recordName: "",
  recordTargetType: "",
  reminderMinutes: 15,
  eventColor: "primary",
  startDate: new Date().toISOString().split("T")[0],
  startTime: "08:00 AM",
  endDate: new Date().toISOString().split("T")[0],
  endTime: "08:30 AM",
  allDay: false,
};

export default function EventFormPage() {
  const { id } = useParams();
  const [searchParams] = useSearchParams();
  const navigate = useNavigate();
  const isEdit = Boolean(id);

  const { data: event, isLoading, error } = useCalendarEventDetail(id);
  const createEvent = useCreateCalendarEvent();
  const updateEvent = useUpdateCalendarEvent();

  const {
    register,
    handleSubmit,
    reset,
    control,
    formState: { errors },
  } = useForm<CalendarEventFormValues>({
    resolver: zodResolver(calendarEventSchema),
    defaultValues: {
      ...defaultValues,
      startDate: searchParams.get("date") ?? defaultValues.startDate,
      endDate: searchParams.get("date") ?? defaultValues.endDate,
    },
  });

  const allDay = useWatch({ control, name: "allDay" });

  useEffect(() => {
    if (event && isEdit) {
      reset({
        title: event.title,
        description: event.description,
        location: event.location,
        recordId: event.recordId,
        recordName: event.recordName,
        recordTargetType: event.recordTargetType,
        reminderMinutes: event.reminderMinutes,
        eventColor: event.eventColor,
        startDate: toDateInputValue(event.startDate),
        startTime: event.startTime || "08:00 AM",
        endDate: toDateInputValue(event.endDate),
        endTime: event.endTime || "08:30 AM",
        allDay: event.allDay,
      });
    }
  }, [event, isEdit, reset]);

  const isSaving = createEvent.isPending || updateEvent.isPending;

  const onSubmit = (values: CalendarEventFormValues) => {
    if (isEdit && id) {
      updateEvent.mutate({ id, values });
      return;
    }
    createEvent.mutate(values);
  };

  if (isEdit && isLoading) {
    return (
      <Box className="flex justify-center p-10">
        <CircularProgress />
      </Box>
    );
  }

  return (
    <Box className="mx-auto max-w-3xl p-4">
      <Paper variant="outlined" className="p-6">
        <Stack spacing={3}>
          <Typography variant="h5">{isEdit ? "Edit Event" : "Create Event"}</Typography>

          {Boolean(error) && <Alert severity="error">Failed to load event</Alert>}

          <Box component="form" onSubmit={handleSubmit(onSubmit)}>
            <Stack spacing={3}>
              <TextField
                label="Title"
                required
                fullWidth
                error={Boolean(errors.title)}
                helperText={errors.title?.message}
                {...register("title")}
                slotProps={{
                  htmlInput: { maxLength: 100 },
                }}
              />

              <TextField
                label="Description"
                fullWidth
                multiline
                rows={3}
                {...register("description")}
              />

              <TextField
                label="Location"
                fullWidth
                {...register("location")}
                slotProps={{
                  htmlInput: { maxLength: 150 },
                }}
              />

              <Controller
                name="reminderMinutes"
                control={control}
                render={({ field }) => (
                  <FormControl fullWidth>
                    <InputLabel>Remind Attendees</InputLabel>
                    <Select
                      label="Remind Attendees"
                      value={field.value}
                      onChange={(event) => field.onChange(Number(event.target.value))}
                    >
                      {CALENDAR_REMINDER_OPTIONS.map((option) => (
                        <MenuItem key={option.value} value={option.value}>
                          {option.label}
                        </MenuItem>
                      ))}
                    </Select>
                  </FormControl>
                )}
              />

              <Controller
                name="eventColor"
                control={control}
                render={({ field }) => (
                  <FormControl fullWidth>
                    <InputLabel>Calendar Color</InputLabel>
                    <Select label="Calendar Color" value={field.value} onChange={field.onChange}>
                      {COLORS.map((color) => (
                        <MenuItem key={color} value={color}>
                          {color}
                        </MenuItem>
                      ))}
                    </Select>
                  </FormControl>
                )}
              />

              {!allDay && (
                <Stack direction={{ xs: "column", sm: "row" }} spacing={2}>
                  <TextField
                    label="Start Date"
                    type="date"
                    fullWidth
                    slotProps={{ inputLabel: { shrink: true } }}
                    error={Boolean(errors.startDate)}
                    helperText={errors.startDate?.message}
                    {...register("startDate")}
                  />
                  <Controller
                    name="startTime"
                    control={control}
                    render={({ field }) => (
                      <FormControl fullWidth>
                        <InputLabel>Start Time</InputLabel>
                        <Select label="Start Time" value={field.value} onChange={field.onChange}>
                          {CALENDAR_TIME_OPTIONS.map((time) => (
                            <MenuItem key={time} value={time}>
                              {time}
                            </MenuItem>
                          ))}
                        </Select>
                      </FormControl>
                    )}
                  />
                </Stack>
              )}

              {!allDay && (
                <Stack direction={{ xs: "column", sm: "row" }} spacing={2}>
                  <TextField
                    label="End Date"
                    type="date"
                    fullWidth
                    slotProps={{ inputLabel: { shrink: true } }}
                    error={Boolean(errors.endDate)}
                    helperText={errors.endDate?.message}
                    {...register("endDate")}
                  />
                  <Controller
                    name="endTime"
                    control={control}
                    render={({ field }) => (
                      <FormControl fullWidth>
                        <InputLabel>End Time</InputLabel>
                        <Select label="End Time" value={field.value} onChange={field.onChange}>
                          {CALENDAR_TIME_OPTIONS.map((time) => (
                            <MenuItem key={time} value={time}>
                              {time}
                            </MenuItem>
                          ))}
                        </Select>
                      </FormControl>
                    )}
                  />
                </Stack>
              )}

              <Controller
                name="allDay"
                control={control}
                render={({ field }) => (
                  <FormControlLabel
                    control={<Checkbox checked={field.value} onChange={field.onChange} />}
                    label="All day event"
                  />
                )}
              />

              <Stack
                direction="row"
                spacing={2}
                sx={{
                  justifyContent: "flex-end",
                }}
              >
                <Button
                  variant="outlined"
                  onClick={() => navigate("/calendar")}
                  disabled={isSaving}
                >
                  Cancel
                </Button>
                <Button type="submit" variant="contained" disabled={isSaving}>
                  {isSaving ? "Saving..." : isEdit ? "Update" : "Create"}
                </Button>
              </Stack>
            </Stack>
          </Box>
        </Stack>
      </Paper>
    </Box>
  );
}