"use client";

import { useState, useEffect, useCallback } from "react";
import { useRouter } from "next/navigation";
import { AuthGuard } from "@/components/auth/AuthGuard";
import { Navbar } from "@/components/layout/Navbar";
import { BottomNav } from "@/components/layout/BottomNav";
import { Button } from "@/components/ui/Button";
import { Spinner } from "@/components/ui/Spinner";
import { api } from "@/lib/api";
import { EquipmentStep } from "@/components/onboarding/EquipmentStep";
import { GoalsStep } from "@/components/onboarding/GoalsStep";
import { WorkoutTypesStep } from "@/components/onboarding/WorkoutTypesStep";
import { ScheduleStep } from "@/components/onboarding/ScheduleStep";
import { DurationStep } from "@/components/onboarding/DurationStep";
import { MusclesStep } from "@/components/onboarding/MusclesStep";
import { InjuryStep } from "@/components/onboarding/InjuryStep";
import { ExcludedExercisesStep } from "@/components/onboarding/ExcludedExercisesStep";
import type { InjuryType } from "@/lib/types";

interface PreferencesData {
  equipment_ids: number[];
  muscle_ids: number[];
  workout_type_ids: number[];
  fitness_level: number;
  primary_goal: string;
  secondary_goal: string;
  days_per_week: number;
  preferred_workout_duration: number;
  preferred_days: number[];
  injury_types: InjuryType[];
  excluded_exercise_ids: number[];
}

export default function PreferencesPage() {
  const router = useRouter();
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState("");
  const [preferences, setPreferences] = useState<PreferencesData>({
    equipment_ids: [],
    muscle_ids: [],
    workout_type_ids: [],
    fitness_level: 1,
    primary_goal: "general_fitness",
    secondary_goal: "",
    days_per_week: 4,
    preferred_workout_duration: 45,
    preferred_days: [],
    injury_types: [],
    excluded_exercise_ids: [],
  });

  useEffect(() => {
    async function fetchExisting() {
      try {
        const existing = await api.getPreferences();
        setPreferences({
          equipment_ids: existing.available_equipment.map((e) => e.id),
          muscle_ids: existing.target_muscle_groups.map((m) => m.id),
          workout_type_ids: existing.preferred_workout_types.map((w) => w.id),
          fitness_level: existing.fitness_level || 1,
          primary_goal: existing.primary_goal || "general_fitness",
          secondary_goal: existing.secondary_goal || "",
          days_per_week: existing.days_per_week || 4,
          preferred_workout_duration: existing.preferred_workout_duration || 45,
          preferred_days: existing.preferred_days || [],
          injury_types: existing.injury_types || [],
          excluded_exercise_ids: existing.excluded_exercises || [],
        });
      } catch {
        // No existing preferences - use defaults
      } finally {
        setLoading(false);
      }
    }
    fetchExisting();
  }, []);

  const updatePreferences = useCallback(
    (updates: Partial<PreferencesData>) => {
      setPreferences((prev) => ({ ...prev, ...updates }));
    },
    []
  );

  const handleSave = async () => {
    setSaving(true);
    setError("");
    try {
      await api.updatePreferences({ ...preferences });
      router.push("/dashboard");
    } catch (err) {
      console.error("Failed to save preferences:", err);
      setError("Failed to save preferences. Please try again.");
    } finally {
      setSaving(false);
    }
  };

  return (
    <AuthGuard>
      <Navbar />
      <BottomNav />
      <main className="pt-20 pb-28 px-4 max-w-2xl mx-auto">
        <h1 className="text-2xl font-bold text-zinc-100 mb-8">Preferences</h1>

        {loading ? (
          <div className="flex items-center justify-center py-20">
            <Spinner size="lg" />
          </div>
        ) : (
          <div className="space-y-12">
            {/* 1. Equipment */}
            <section>
              <EquipmentStep
                selectedIds={preferences.equipment_ids}
                onChange={(ids) => updatePreferences({ equipment_ids: ids })}
              />
            </section>

            <hr className="border-zinc-800" />

            {/* 2. Goals */}
            <section>
              <GoalsStep
                fitnessLevel={preferences.fitness_level}
                primaryGoal={preferences.primary_goal}
                secondaryGoal={preferences.secondary_goal}
                onChange={(data) => updatePreferences(data)}
              />
            </section>

            <hr className="border-zinc-800" />

            {/* 3. Workout Types */}
            <section>
              <WorkoutTypesStep
                selectedIds={preferences.workout_type_ids}
                onChange={(ids) =>
                  updatePreferences({ workout_type_ids: ids })
                }
              />
            </section>

            <hr className="border-zinc-800" />

            {/* 4. Schedule */}
            <section>
              <ScheduleStep
                daysPerWeek={preferences.days_per_week}
                preferredDays={preferences.preferred_days}
                onChange={(data) => updatePreferences(data)}
              />
            </section>

            <hr className="border-zinc-800" />

            {/* 5. Duration */}
            <section>
              <DurationStep
                duration={preferences.preferred_workout_duration}
                onChange={(min) =>
                  updatePreferences({ preferred_workout_duration: min })
                }
              />
            </section>

            <hr className="border-zinc-800" />

            {/* 6. Target Muscles */}
            <section>
              <MusclesStep
                selectedIds={preferences.muscle_ids}
                onChange={(ids) => updatePreferences({ muscle_ids: ids })}
              />
            </section>

            <hr className="border-zinc-800" />

            {/* 7. Injuries */}
            <section>
              <InjuryStep
                injuryTypes={preferences.injury_types}
                onChange={(injuries) =>
                  updatePreferences({ injury_types: injuries })
                }
              />
            </section>

            <hr className="border-zinc-800" />

            {/* 8. Excluded Exercises */}
            <section>
              <ExcludedExercisesStep
                selectedIds={preferences.excluded_exercise_ids}
                onChange={(ids) =>
                  updatePreferences({ excluded_exercise_ids: ids })
                }
              />
            </section>
          </div>
        )}

        {/* Sticky save bar */}
        {!loading && (
          <div className="fixed bottom-16 md:bottom-0 left-0 right-0 z-40 bg-zinc-950/95 backdrop-blur border-t border-zinc-800 px-4 py-3">
            <div className="max-w-2xl mx-auto flex items-center justify-between">
              <div className="text-sm">
                {error && (
                  <span className="text-red-400">{error}</span>
                )}
              </div>
              <Button
                variant="primary"
                onClick={handleSave}
                loading={saving}
              >
                Save
              </Button>
            </div>
          </div>
        )}
      </main>
    </AuthGuard>
  );
}