"use client";

import { useState } from "react";
import { Exercise } from "@prisma/client";
import { Loader2 } from "lucide-react";

const EXERCISE_TYPES = [
  "barbell",
  "dumbbell",
  "machine",
  "cable",
  "bodyweight",
  "cardio",
  "kettlebell",
  "other",
];

const MUSCLE_GROUPS = [
  "chest",
  "back",
  "shoulders",
  "biceps",
  "triceps",
  "forearms",
  "quads",
  "hamstrings",
  "glutes",
  "calves",
  "core",
  "cardio",
];

const INPUT_FIELD_OPTIONS = [
  { value: "sets", label: "Sets" },
  { value: "reps", label: "Reps" },
  { value: "weight", label: "Weight" },
  { value: "duration", label: "Duration" },
  { value: "distance", label: "Distance" },
  { value: "calories", label: "Calories" },
];

interface AddExerciseFormProps {
  onExerciseAdded: (exercise: Exercise) => void;
}

export default function AddExerciseForm({
  onExerciseAdded,
}: AddExerciseFormProps) {
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [formData, setFormData] = useState({
    name: "",
    type: "barbell",
    muscleGroups: [] as string[],
    inputFields: ["sets", "reps", "weight"] as string[],
    description: "",
  });

  const handleMuscleGroupToggle = (group: string) => {
    setFormData((prev) => {
      const groups = prev.muscleGroups.includes(group)
        ? prev.muscleGroups.filter((g) => g !== group)
        : [...prev.muscleGroups, group];
      return { ...prev, muscleGroups: groups };
    });
  };

  const handleInputFieldToggle = (field: string) => {
    setFormData((prev) => {
      const fields = prev.inputFields.includes(field)
        ? prev.inputFields.filter((f) => f !== field)
        : [...prev.inputFields, field];
      return { ...prev, inputFields: fields };
    });
  };

  // Auto-set sensible input fields when type changes
  const handleTypeChange = (type: string) => {
    let defaultFields = ["sets", "reps", "weight"];
    if (type === "cardio") {
      defaultFields = ["sets", "duration", "calories"];
    } else if (type === "bodyweight") {
      defaultFields = ["sets", "reps"];
    }
    setFormData((prev) => ({
      ...prev,
      type,
      inputFields: defaultFields,
    }));
  };

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    setError(null);
    setLoading(true);

    try {
      const response = await fetch("/api/exercises", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          name: formData.name,
          type: formData.type,
          muscleGroups: formData.muscleGroups,
          inputFields: formData.inputFields,
          description: formData.description || undefined,
        }),
      });

      if (!response.ok) {
        const data = await response.json();
        throw new Error(data.error || "Failed to add exercise");
      }

      const exercise = await response.json();
      onExerciseAdded(exercise);

      setFormData({
        name: "",
        type: "barbell",
        muscleGroups: [],
        inputFields: ["sets", "reps", "weight"],
        description: "",
      });
    } catch (err) {
      setError(err instanceof Error ? err.message : "An error occurred");
    } finally {
      setLoading(false);
    }
  };

  return (
    <form onSubmit={handleSubmit} className="space-y-5">
      {error && (
        <div className="bg-red-900/50 border border-red-800 rounded-lg p-3 text-red-400 text-sm">
          {error}
        </div>
      )}

      {/* Name */}
      <div>
        <label className="block text-xs font-medium text-zinc-400 uppercase tracking-wider mb-2">
          Exercise Name
        </label>
        <input
          type="text"
          required
          value={formData.name}
          onChange={(e) =>
            setFormData((prev) => ({ ...prev, name: e.target.value }))
          }
          className="w-full px-4 py-3 bg-zinc-800 border border-zinc-700 rounded-lg text-white placeholder:text-zinc-500 focus:outline-none focus:ring-2 focus:ring-white/20"
          placeholder="e.g., Barbell Bench Press"
        />
      </div>

      {/* Equipment */}
      <div>
        <label className="block text-xs font-medium text-zinc-400 uppercase tracking-wider mb-2">
          Equipment
        </label>
        <div className="flex flex-wrap gap-2">
          {EXERCISE_TYPES.map((type) => (
            <button
              key={type}
              type="button"
              onClick={() => handleTypeChange(type)}
              className={`px-3 py-1.5 rounded-lg text-sm font-medium transition ${
                formData.type === type
                  ? "bg-white text-black"
                  : "bg-zinc-800 text-zinc-400 hover:text-white"
              }`}
            >
              {type.charAt(0).toUpperCase() + type.slice(1)}
            </button>
          ))}
        </div>
      </div>

      {/* Input Fields */}
      <div>
        <label className="block text-xs font-medium text-zinc-400 uppercase tracking-wider mb-1">
          Tracked Fields
        </label>
        <p className="text-xs text-zinc-600 mb-2">
          What data do you log for this exercise?
        </p>
        <div className="flex flex-wrap gap-2">
          {INPUT_FIELD_OPTIONS.map((field) => (
            <button
              key={field.value}
              type="button"
              onClick={() => handleInputFieldToggle(field.value)}
              className={`px-3 py-1.5 rounded-lg text-sm font-medium transition ${
                formData.inputFields.includes(field.value)
                  ? "bg-white text-black"
                  : "bg-zinc-800 text-zinc-400 hover:text-white"
              }`}
            >
              {field.label}
            </button>
          ))}
        </div>
      </div>

      {/* Muscle Groups */}
      <div>
        <label className="block text-xs font-medium text-zinc-400 uppercase tracking-wider mb-2">
          Muscle Groups
        </label>
        <div className="flex flex-wrap gap-2">
          {MUSCLE_GROUPS.map((group) => (
            <button
              key={group}
              type="button"
              onClick={() => handleMuscleGroupToggle(group)}
              className={`px-3 py-1.5 rounded-lg text-sm font-medium transition ${
                formData.muscleGroups.includes(group)
                  ? "bg-white text-black"
                  : "bg-zinc-800 text-zinc-400 hover:text-white"
              }`}
            >
              {group.charAt(0).toUpperCase() + group.slice(1)}
            </button>
          ))}
        </div>
      </div>

      {/* Description */}
      <div>
        <label className="block text-xs font-medium text-zinc-400 uppercase tracking-wider mb-2">
          Description (optional)
        </label>
        <textarea
          value={formData.description}
          onChange={(e) =>
            setFormData((prev) => ({ ...prev, description: e.target.value }))
          }
          className="w-full px-4 py-3 bg-zinc-800 border border-zinc-700 rounded-lg text-white placeholder:text-zinc-500 focus:outline-none focus:ring-2 focus:ring-white/20 resize-none"
          placeholder="Notes about form, tips, or variations..."
          rows={2}
        />
      </div>

      {/* Submit */}
      <button
        type="submit"
        disabled={loading || !formData.name}
        className="w-full bg-white hover:bg-zinc-200 disabled:bg-zinc-700 disabled:text-zinc-500 text-black font-bold py-3 px-4 rounded-lg transition flex items-center justify-center gap-2"
      >
        {loading && <Loader2 className="w-4 h-4 animate-spin" />}
        {loading ? "Adding..." : "Add Exercise"}
      </button>
    </form>
  );
}