/**
 * Departure Recurring Rule Form
 * Create and edit recurring rules for departures
 */

import React, { useState, useEffect } from "react";
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import { ArrowLeft, Save, Loader2 } from "lucide-react";
import { __ } from "../lib/i18n";
import { toDateValue } from "../lib/dateFormat";
import { Button } from "../components/ui/button";
import { Input } from "../components/ui/input";
import { Select } from "../components/ui/select";
import { PageHeader } from "../components/common/PageHeader";
import { Card, CardContent } from "../components/ui/card";
import { HelpText } from "../components/ui/help-text";
import { DatePicker } from "../components/ui/date-picker";
import { apiClient } from "../lib/api-client";
import { useToast } from "../components/ui/toast";

interface RecurringRuleFormData {
  recurrence_type: "daily" | "weekly" | "monthly" | "custom_days";
  weekdays: number[];
  start_date?: string;
  end_date?: string;
  max_capacity: string;
  base_price?: string;
  is_active: boolean;
}

const dayOptions = [
  { value: 0, label: __("Sunday", "yatra") },
  { value: 1, label: __("Monday", "yatra") },
  { value: 2, label: __("Tuesday", "yatra") },
  { value: 3, label: __("Wednesday", "yatra") },
  { value: 4, label: __("Thursday", "yatra") },
  { value: 5, label: __("Friday", "yatra") },
  { value: 6, label: __("Saturday", "yatra") },
];

const DepartureRecurringRuleForm: React.FC = () => {
  const queryClient = useQueryClient();
  const { showToast } = useToast();

  // Get trip_id and id from URL
  const urlParams = new URLSearchParams(window.location.search);
  const tripId = urlParams.get("trip_id")
    ? parseInt(urlParams.get("trip_id")!)
    : null;
  const ruleId = urlParams.get("id") || null;
  const isEditMode = !!ruleId;

  const [formData, setFormData] = useState<RecurringRuleFormData>({
    recurrence_type: "weekly",
    weekdays: [],
    start_date: "",
    end_date: "",
    max_capacity: "",
    base_price: "",
    is_active: true,
  });

  const [errors, setErrors] = useState<
    Partial<Record<keyof RecurringRuleFormData, string>>
  >({});

  // Fetch existing rule data if editing
  const { data: ruleData, isLoading: isLoadingRule } = useQuery({
    queryKey: ["recurring-rule", ruleId],
    queryFn: async () => {
      if (!ruleId || !tripId) return null;
      const response = await apiClient.get(
        `/trips/${tripId}/recurring-rules/${ruleId}`,
      );
      return response?.data || response;
    },
    enabled: isEditMode && !!ruleId && !!tripId,
  });

  // Load form data when rule data is available
  useEffect(() => {
    if (ruleData) {
      setFormData({
        recurrence_type: ruleData.recurrence_type || "weekly",
        weekdays: ruleData.weekdays || [],
        start_date: ruleData.start_date || "",
        end_date: ruleData.end_date || "",
        max_capacity: ruleData.max_capacity?.toString() || "",
        base_price: ruleData.base_price?.toString() || "",
        is_active: ruleData.is_active !== false,
      });
    }
  }, [ruleData]);

  // Create/Update mutation
  const saveMutation = useMutation({
    mutationFn: async (data: RecurringRuleFormData) => {
      if (!tripId) throw new Error("Trip ID is required");

      const payload: any = {
        trip_id: tripId,
        recurrence_type: data.recurrence_type,
        max_capacity: parseInt(data.max_capacity),
        is_active: data.is_active,
      };

      if (
        data.recurrence_type === "weekly" ||
        data.recurrence_type === "custom_days"
      ) {
        payload.weekdays = data.weekdays;
      }

      if (data.start_date) payload.start_date = data.start_date;
      if (data.end_date) payload.end_date = data.end_date;
      if (data.base_price) payload.base_price = parseFloat(data.base_price);

      if (isEditMode && ruleId) {
        return await apiClient.put(
          `/trips/${tripId}/recurring-rules/${ruleId}`,
          payload,
        );
      } else {
        return await apiClient.post(
          `/trips/${tripId}/recurring-rules`,
          payload,
        );
      }
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["recurring-rules", tripId] });
      showToast(
        isEditMode
          ? __("Recurring rule updated successfully", "yatra")
          : __("Recurring rule created successfully", "yatra"),
        "success",
      );
      window.location.href = `?page=yatra&subpage=trips&tab=departures&action=rules&trip_id=${tripId}`;
    },
    onError: (error: any) => {
      showToast(error?.message || __("Failed to save rule", "yatra"), "error");
    },
  });

  const validateForm = (): boolean => {
    const newErrors: Partial<Record<keyof RecurringRuleFormData, string>> = {};

    if (!formData.max_capacity) {
      newErrors.max_capacity = __("Max capacity is required", "yatra");
    } else if (parseInt(formData.max_capacity) < 1) {
      newErrors.max_capacity = __("Max capacity must be at least 1", "yatra");
    }

    if (
      (formData.recurrence_type === "weekly" ||
        formData.recurrence_type === "custom_days") &&
      formData.weekdays.length === 0
    ) {
      newErrors.weekdays = __("At least one weekday must be selected", "yatra");
    }

    setErrors(newErrors);
    return Object.keys(newErrors).length === 0;
  };

  const handleSubmit = (e: React.FormEvent) => {
    e.preventDefault();
    if (validateForm()) {
      saveMutation.mutate(formData);
    }
  };

  const handleBack = () => {
    window.location.href = `?page=yatra&subpage=trips&tab=departures&action=rules${tripId ? `&trip_id=${tripId}` : ""}`;
  };

  const toggleWeekday = (day: number) => {
    setFormData({
      ...formData,
      weekdays: formData.weekdays.includes(day)
        ? formData.weekdays.filter((d) => d !== day)
        : [...formData.weekdays, day].sort(),
    });
  };

  if (isLoadingRule) {
    return (
      <div className="space-y-6">
        <div className="animate-pulse">
          <div className="h-8 bg-gray-200 dark:bg-gray-700 rounded w-1/4 mb-4"></div>
          <div className="h-64 bg-gray-200 dark:bg-gray-700 rounded"></div>
        </div>
      </div>
    );
  }

  return (
    <div className="space-y-6">
      <PageHeader
        title={
          isEditMode
            ? __("Edit Recurring Rule", "yatra")
            : __("Add Recurring Rule", "yatra")
        }
        description={__(
          "Create a recurring pattern for automatic departure date generation",
          "yatra",
        )}
        actions={
          <Button variant="ghost" onClick={handleBack}>
            <ArrowLeft className="w-4 h-4 mr-2" />
            {__("Back", "yatra")}
          </Button>
        }
      />

      <form onSubmit={handleSubmit}>
        <Card>
          <CardContent className="pt-6 space-y-6">
            {/* Recurrence Type */}
            <div>
              <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
                {__("Recurrence Type", "yatra")}{" "}
                <span className="text-red-500">*</span>
              </label>
              <Select
                value={formData.recurrence_type}
                onChange={(e) => {
                  setFormData({
                    ...formData,
                    recurrence_type: e.target.value as any,
                    weekdays: [],
                  });
                }}
              >
                <option value="daily">{__("Daily", "yatra")}</option>
                <option value="weekly">{__("Weekly", "yatra")}</option>
                <option value="monthly">{__("Monthly", "yatra")}</option>
                <option value="custom_days">
                  {__("Custom Days", "yatra")}
                </option>
              </Select>
              <HelpText
                text={__(
                  "Select how often departures should be generated",
                  "yatra",
                )}
              />
            </div>

            {/* Weekdays (for weekly/custom_days) */}
            {(formData.recurrence_type === "weekly" ||
              formData.recurrence_type === "custom_days") && (
              <div>
                <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
                  {__("Days of Week", "yatra")}{" "}
                  <span className="text-red-500">*</span>
                </label>
                <div className="flex flex-wrap gap-2">
                  {dayOptions.map((day) => (
                    <button
                      key={day.value}
                      type="button"
                      onClick={() => toggleWeekday(day.value)}
                      className={`px-4 py-2 rounded-md border ${
                        formData.weekdays.includes(day.value)
                          ? "bg-blue-500 text-white border-blue-500"
                          : "bg-white dark:bg-gray-800 text-gray-700 dark:text-gray-300 border-gray-300 dark:border-gray-600 hover:bg-gray-50 dark:hover:bg-gray-700"
                      }`}
                    >
                      {day.label}
                    </button>
                  ))}
                </div>
                {errors.weekdays && (
                  <p className="mt-1 text-sm text-red-600 dark:text-red-400">
                    {errors.weekdays}
                  </p>
                )}
                <HelpText
                  text={__(
                    "Select which days of the week departures should be generated",
                    "yatra",
                  )}
                />
              </div>
            )}

            {/* Start Date */}
            <div>
              <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
                {__("Start Date", "yatra")}{" "}
                <span className="text-gray-400">
                  ({__("Optional", "yatra")})
                </span>
              </label>
              <DatePicker
                value={formData.start_date || ""}
                onChange={(value) =>
                  setFormData({ ...formData, start_date: value })
                }
              />
              <HelpText
                text={__(
                  "When should this rule start generating dates?",
                  "yatra",
                )}
              />
            </div>

            {/* End Date */}
            <div>
              <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
                {__("End Date", "yatra")}{" "}
                <span className="text-gray-400">
                  ({__("Optional", "yatra")})
                </span>
              </label>
              <DatePicker
                value={formData.end_date || ""}
                onChange={(value) =>
                  setFormData({ ...formData, end_date: value })
                }
                minDate={
                  formData.start_date
                    ? toDateValue(formData.start_date)
                    : undefined
                }
              />
              <HelpText
                text={__(
                  "When should this rule stop generating dates? Leave empty for no end date",
                  "yatra",
                )}
              />
            </div>

            {/* Max Capacity */}
            <div>
              <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
                {__("Max Capacity", "yatra")}{" "}
                <span className="text-red-500">*</span>
              </label>
              <Input
                type="number"
                min="1"
                value={formData.max_capacity}
                onChange={(e) =>
                  setFormData({ ...formData, max_capacity: e.target.value })
                }
                placeholder={__("e.g., 20", "yatra")}
              />
              {errors.max_capacity && (
                <p className="mt-1 text-sm text-red-600 dark:text-red-400">
                  {errors.max_capacity}
                </p>
              )}
              <HelpText
                text={__(
                  "Maximum number of travelers for generated departures",
                  "yatra",
                )}
              />
            </div>

            {/* Base Price (Optional) */}
            <div>
              <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
                {__("Base Price", "yatra")}{" "}
                <span className="text-gray-400">
                  ({__("Optional", "yatra")})
                </span>
              </label>
              <Input
                type="number"
                step="0.01"
                min="0"
                value={formData.base_price || ""}
                onChange={(e) =>
                  setFormData({ ...formData, base_price: e.target.value })
                }
                placeholder={__("e.g., 150.00", "yatra")}
              />
              <HelpText
                text={__(
                  "Base price per person for generated departures (optional)",
                  "yatra",
                )}
              />
            </div>

            {/* Active Status */}
            <div>
              <label className="flex items-center gap-2">
                <input
                  type="checkbox"
                  checked={formData.is_active}
                  onChange={(e) =>
                    setFormData({ ...formData, is_active: e.target.checked })
                  }
                  className="rounded border-gray-300 text-blue-600 focus:ring-blue-500"
                />
                <span className="text-sm font-medium text-gray-700 dark:text-gray-300">
                  {__("Active", "yatra")}
                </span>
              </label>
              <HelpText
                text={__(
                  "Only active rules will generate departure dates",
                  "yatra",
                )}
              />
            </div>

            {/* Submit Button */}
            <div className="flex justify-end gap-3 pt-4 border-t border-gray-200 dark:border-gray-700">
              <Button type="button" variant="outline" onClick={handleBack}>
                {__("Cancel", "yatra")}
              </Button>
              <Button type="submit" disabled={saveMutation.isPending}>
                {saveMutation.isPending ? (
                  <>
                    <Loader2 className="w-4 h-4 mr-2 animate-spin" />
                    {__("Saving...", "yatra")}
                  </>
                ) : (
                  <>
                    <Save className="w-4 h-4 mr-2" />
                    {__("Save Rule", "yatra")}
                  </>
                )}
              </Button>
            </div>
          </CardContent>
        </Card>
      </form>
    </div>
  );
};

export default DepartureRecurringRuleForm;
