import { useState, useCallback } from "react";
import type { WorkoutSet, StrokeType, RestType } from "@types/workout";
import { saveWorkout, saveTemplate } from "@db/operations";

const DEFAULT_SET: WorkoutSet = {
  stroke: "Freestyle",
  distancePerRep: 200,
  repCount: 1,
  restType: "fixed_rest",
  restDuration: 30,
};

export function useWorkoutBuilder(initialSets?: WorkoutSet[]) {
  const [sets, setSets] = useState<WorkoutSet[]>(initialSets ?? [{ ...DEFAULT_SET }]);
  const [workoutName, setWorkoutName] = useState("");
  const [isSaving, setIsSaving] = useState(false);

  const addSet = useCallback(() => {
    setSets((prev) => [...prev, { ...DEFAULT_SET }]);
  }, []);

  const updateSet = useCallback((index: number, updates: Partial<WorkoutSet>) => {
    setSets((prev) => prev.map((s, i) => (i === index ? { ...s, ...updates } : s)));
  }, []);

  const removeSet = useCallback((index: number) => {
    setSets((prev) => prev.filter((_, i) => i !== index));
  }, []);

  const totalDistance = sets.reduce((acc, s) => acc + s.distancePerRep * s.repCount, 0);

  const save = useCallback(
    async (poolLength: number, templateId?: string) => {
      setIsSaving(true);
      try {
        const name = workoutName.trim() || `Workout ${new Date().toLocaleDateString()}`;
        const id = await saveWorkout(name, poolLength, sets, templateId);
        return id;
      } finally {
        setIsSaving(false);
      }
    },
    [workoutName, sets]
  );

  const saveAsTemplate = useCallback(
    async (templateName: string, poolLength: number) => {
      setIsSaving(true);
      try {
        const id = await saveTemplate(templateName, poolLength, sets);
        return id;
      } finally {
        setIsSaving(false);
      }
    },
    [sets]
  );

  const loadTemplate = useCallback((templateSets: WorkoutSet[], name?: string) => {
    setSets(templateSets);
    if (name) setWorkoutName(name);
  }, []);

  const reset = useCallback(() => {
    setSets([{ ...DEFAULT_SET }]);
    setWorkoutName("");
  }, []);

  return {
    sets,
    workoutName,
    setWorkoutName,
    totalDistance,
    isSaving,
    addSet,
    updateSet,
    removeSet,
    save,
    saveAsTemplate,
    loadTemplate,
    reset,
  };
}