'use client';

import { useAuth } from '@/components/auth/AuthContext';
import { useRouter } from 'next/navigation';
import { FormEvent, useCallback, useEffect, useState } from 'react';

import { LeagueWizardCommandModel } from '@/lib/command-models/leagues/LeagueWizardCommandModel';
import { useLeagueScoringPresets } from "@/hooks/useLeagueScoringPresets";
import { useCreateLeagueWizard } from "@/hooks/useLeagueWizardService";
import type { LeagueConfigFormModel } from '@/lib/types/LeagueConfigFormModel';
import type { Weekday } from '@/lib/types/Weekday';
import type { WizardErrors } from '@/lib/types/WizardErrors';
import type { LeagueScoringPresetViewModel } from '@/lib/view-models/LeagueScoringPresetViewModel';
import { CreateLeagueWizardTemplate, Step } from '@/templates/CreateLeagueWizardTemplate';
import { SearchParamBuilder } from '@/lib/routing/search-params/SearchParamBuilder';
import { 
  Award, 
  Calendar, 
  CheckCircle2, 
  FileText, 
  Scale, 
  Trophy, 
  Users 
} from 'lucide-react';

// ============================================================================
// LOCAL STORAGE PERSISTENCE
// ============================================================================

const STORAGE_KEY = 'gridpilot_league_wizard_draft';
const STORAGE_HIGHEST_STEP_KEY = 'gridpilot_league_wizard_highest_step';

function saveFormToStorage(form: LeagueWizardFormModel): void {
  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify(form));
  } catch {
    // Ignore storage errors
  }
}

function loadFormFromStorage(): LeagueWizardFormModel | null {
  try {
    const stored = localStorage.getItem(STORAGE_KEY);
    if (stored) {
      const parsed = JSON.parse(stored) as LeagueWizardFormModel;
      if (!parsed.seasonName) {
        const seasonStartDate = parsed.timings?.seasonStartDate;
        parsed.seasonName = getDefaultSeasonName(seasonStartDate);
      }
      return parsed;
    }
  } catch {
    // Ignore parse errors
  }
  return null;
}

function clearFormStorage(): void {
  try {
    localStorage.removeItem(STORAGE_KEY);
    localStorage.removeItem(STORAGE_HIGHEST_STEP_KEY);
  } catch {
    // Ignore storage errors
  }
}

function saveHighestStep(step: number): void {
  try {
    const current = getHighestStep();
    if (step > current) {
      localStorage.setItem(STORAGE_HIGHEST_STEP_KEY, String(step));
    }
  } catch {
    // Ignore storage errors
  }
}

function getHighestStep(): number {
  try {
    const stored = localStorage.getItem(STORAGE_HIGHEST_STEP_KEY);
    return stored ? parseInt(stored, 10) : 1;
  } catch {
    return 1;
  }
}

type StepName = 'basics' | 'visibility' | 'structure' | 'schedule' | 'scoring' | 'stewarding' | 'review';

type LeagueWizardFormModel = LeagueConfigFormModel & {
  seasonName?: string;
};

interface CreateLeagueWizardProps {
  stepName: StepName;
  onStepChange?: (stepName: StepName) => void;
}

function stepNameToStep(stepName: StepName): Step {
  switch (stepName) {
    case 'basics': return 1;
    case 'visibility': return 2;
    case 'structure': return 3;
    case 'schedule': return 4;
    case 'scoring': return 5;
    case 'stewarding': return 6;
    case 'review': return 7;
  }
}

function stepToStepName(step: Step): StepName {
  switch (step) {
    case 1: return 'basics';
    case 2: return 'visibility';
    case 3: return 'structure';
    case 4: return 'schedule';
    case 5: return 'scoring';
    case 6: return 'stewarding';
    case 7: return 'review';
  }
}

function getDefaultSeasonStartDate(): string {
  const now = new Date();
  const daysUntilSaturday = (6 - now.getDay() + 7) % 7 || 7;
  const nextSaturday = new Date(now);
  nextSaturday.setDate(now.getDate() + daysUntilSaturday);
  const [datePart] = nextSaturday.toISOString().split('T');
  return datePart ?? '';
}

function getDefaultSeasonName(seasonStartDate?: string): string {
  if (seasonStartDate) {
    const parsed = new Date(seasonStartDate);
    if (!Number.isNaN(parsed.getTime())) {
      const year = parsed.getFullYear();
      return `Season 1 (${year})`;
    }
  }
  const fallbackYear = new Date().getFullYear();
  return `Season 1 (${fallbackYear})`;
}

function createDefaultForm(): LeagueWizardFormModel {
  const defaultPatternId = 'sprint-main-driver';
  const defaultSeasonStartDate = getDefaultSeasonStartDate();

  return {
    basics: {
      name: '',
      description: '',
      visibility: 'public',
      gameId: 'iracing',
    },
    structure: {
      mode: 'solo',
      maxDrivers: 24,
      multiClassEnabled: false,
    },
    championships: {
      enableDriverChampionship: true,
      enableTeamChampionship: false,
      enableNationsChampionship: false,
      enableTrophyChampionship: false,
    },
    scoring: {
      patternId: defaultPatternId,
      customScoringEnabled: false,
    },
    dropPolicy: {
      strategy: 'bestNResults',
      n: 6,
    },
    timings: {
      practiceMinutes: 20,
      qualifyingMinutes: 30,
      sprintRaceMinutes: 20,
      mainRaceMinutes: 40,
      sessionCount: 2,
      roundsPlanned: 8,
      weekdays: ['Sat'] as Weekday[],
      recurrenceStrategy: 'weekly' as const,
      timezoneId: 'UTC',
      seasonStartDate: defaultSeasonStartDate,
    },
    stewarding: {
      decisionMode: 'admin_only',
      requiredVotes: 2,
      requireDefense: false,
      defenseTimeLimit: 48,
      voteTimeLimit: 72,
      protestDeadlineHours: 48,
      stewardingClosesHours: 168,
      notifyAccusedOnProtest: true,
      notifyOnVoteRequired: true,
    },
    seasonName: getDefaultSeasonName(defaultSeasonStartDate),
  };
}

export function CreateLeagueWizard({ stepName, onStepChange }: CreateLeagueWizardProps) {
  const router = useRouter();
  const { session } = useAuth();

  const handleStepChange = useCallback((newStepName: StepName) => {
    if (onStepChange) {
      onStepChange(newStepName);
    } else {
      const builder = new SearchParamBuilder();
      builder.step(newStepName);
      router.push(`/leagues/create${builder.build()}`);
    }
  }, [onStepChange, router]);

  const step = stepNameToStep(stepName);
  const [loading, setLoading] = useState(false);
  const [presetsLoading, setPresetsLoading] = useState(true);
  const [presets, setPresets] = useState<LeagueScoringPresetViewModel[]>([]);
  const [errors, setErrors] = useState<WizardErrors>({});
  const [highestCompletedStep, setHighestCompletedStep] = useState(1);
  const [isHydrated, setIsHydrated] = useState(false);
  
  const [form, setForm] = useState<LeagueWizardFormModel>(() =>
    createDefaultForm(),
  );

  useEffect(() => {
    const stored = loadFormFromStorage();
    if (stored) {
      setForm(stored);
    }
    setHighestCompletedStep(getHighestStep());
    setIsHydrated(true);
  }, []);

  useEffect(() => {
    if (isHydrated) {
      saveFormToStorage(form);
    }
  }, [form, isHydrated]);

  useEffect(() => {
    if (isHydrated) {
      saveHighestStep(step);
      setHighestCompletedStep((prev) => Math.max(prev, step));
    }
  }, [step, isHydrated]);

  const { data: queryPresets, error: presetsError } = useLeagueScoringPresets();

  useEffect(() => {
    if (queryPresets) {
      setPresets(queryPresets as any);
      const firstPreset = queryPresets[0];
      if (firstPreset && !form.scoring?.patternId) {
        setForm((prev) => ({
          ...prev,
          scoring: {
            ...prev.scoring,
            patternId: firstPreset.id,
            customScoringEnabled: false,
          },
        }));
      }
      setPresetsLoading(false);
    }
  }, [queryPresets, form.scoring?.patternId]);

  useEffect(() => {
    if (presetsError) {
      setErrors((prev) => ({
        ...prev,
        submit: presetsError instanceof Error ? presetsError.message : 'Failed to load scoring presets',
      }));
    }
  }, [presetsError]);

  const createLeagueMutation = useCreateLeagueWizard();

  const validateStep = (currentStep: Step): boolean => {
    const formData: any = {
      leagueId: form.leagueId || '',
      basics: {
        name: form.basics?.name || '',
        description: form.basics?.description || '',
        visibility: (form.basics?.visibility as 'public' | 'private' | 'unlisted') || 'public',
        gameId: form.basics?.gameId || 'iracing',
      },
      structure: {
        mode: (form.structure?.mode as 'solo' | 'fixedTeams') || 'solo',
        maxDrivers: form.structure?.maxDrivers || 0,
        maxTeams: form.structure?.maxTeams || 0,
        driversPerTeam: form.structure?.driversPerTeam || 0,
      },
      championships: {
        enableDriverChampionship: form.championships?.enableDriverChampionship ?? true,
        enableTeamChampionship: form.championships?.enableTeamChampionship ?? false,
        enableNationsChampionship: form.championships?.enableNationsChampionship ?? false,
        enableTrophyChampionship: form.championships?.enableTrophyChampionship ?? false,
      },
      scoring: {
        patternId: form.scoring?.patternId || '',
        customScoringEnabled: form.scoring?.customScoringEnabled ?? false,
      },
      dropPolicy: {
        strategy: (form.dropPolicy?.strategy as 'none' | 'bestNResults' | 'dropWorstN') || 'bestNResults',
        n: form.dropPolicy?.n || 6,
      },
      timings: {
        practiceMinutes: form.timings?.practiceMinutes || 0,
        qualifyingMinutes: form.timings?.qualifyingMinutes || 0,
        sprintRaceMinutes: form.timings?.sprintRaceMinutes || 0,
        mainRaceMinutes: form.timings?.mainRaceMinutes || 0,
        sessionCount: form.timings?.sessionCount || 0,
        roundsPlanned: form.timings?.roundsPlanned || 0,
      },
      stewarding: {
        decisionMode: (form.stewarding?.decisionMode as 'owner_only' | 'admin_vote' | 'steward_panel') || 'admin_only',
        requiredVotes: form.stewarding?.requiredVotes || 0,
        requireDefense: form.stewarding?.requireDefense ?? false,
        defenseTimeLimit: form.stewarding?.defenseTimeLimit || 0,
        voteTimeLimit: form.stewarding?.voteTimeLimit || 0,
        protestDeadlineHours: form.stewarding?.protestDeadlineHours || 0,
        stewardingClosesHours: form.stewarding?.stewardingClosesHours || 0,
        notifyAccusedOnProtest: form.stewarding?.notifyAccusedOnProtest ?? true,
        notifyOnVoteRequired: form.stewarding?.notifyOnVoteRequired ?? true,
      },
    };

    const stepErrors = LeagueWizardCommandModel.validateLeagueWizardStep(formData, currentStep as any);
    setErrors((prev) => ({
      ...prev,
      ...stepErrors,
    }));
    return !LeagueWizardCommandModel.hasWizardErrors(stepErrors);
  };

  const goToNextStep = () => {
    if (!validateStep(step)) {
      return;
    }
    const nextStep = (step < 7 ? ((step + 1) as Step) : step);
    saveHighestStep(nextStep);
    setHighestCompletedStep((prev) => Math.max(prev, nextStep));
    handleStepChange(stepToStepName(nextStep));
  };

  const goToPreviousStep = () => {
    const prevStep = (step > 1 ? ((step - 1) as Step) : step);
    handleStepChange(stepToStepName(prevStep));
  };

  const goToStep = useCallback((targetStep: Step) => {
    if (targetStep <= highestCompletedStep) {
      handleStepChange(stepToStepName(targetStep));
    }
  }, [highestCompletedStep, handleStepChange]);

  const handleSubmit = async (event: FormEvent) => {
    event.preventDefault();
    if (loading) return;

    const ownerId = session?.user.userId;
    if (!ownerId) {
      setErrors((prev) => ({
        ...prev,
        submit: 'You must be logged in to create a league',
      }));
      return;
    }

    const formData: any = {
      leagueId: form.leagueId || '',
      basics: {
        name: form.basics?.name || '',
        description: form.basics?.description || '',
        visibility: (form.basics?.visibility as 'public' | 'private' | 'unlisted') || 'public',
        gameId: form.basics?.gameId || 'iracing',
      },
      structure: {
        mode: (form.structure?.mode as 'solo' | 'fixedTeams') || 'solo',
        maxDrivers: form.structure?.maxDrivers || 0,
        maxTeams: form.structure?.maxTeams || 0,
        driversPerTeam: form.structure?.driversPerTeam || 0,
      },
      championships: {
        enableDriverChampionship: form.championships?.enableDriverChampionship ?? true,
        enableTeamChampionship: form.championships?.enableTeamChampionship ?? false,
        enableNationsChampionship: form.championships?.enableNationsChampionship ?? false,
        enableTrophyChampionship: form.championships?.enableTrophyChampionship ?? false,
      },
      scoring: {
        patternId: form.scoring?.patternId || '',
        customScoringEnabled: form.scoring?.customScoringEnabled ?? false,
      },
      dropPolicy: {
        strategy: (form.dropPolicy?.strategy as 'none' | 'bestNResults' | 'dropWorstN') || 'bestNResults',
        n: form.dropPolicy?.n || 6,
      },
      timings: {
        practiceMinutes: form.timings?.practiceMinutes || 0,
        qualifyingMinutes: form.timings?.qualifyingMinutes || 0,
        sprintRaceMinutes: form.timings?.sprintRaceMinutes || 0,
        mainRaceMinutes: form.timings?.mainRaceMinutes || 0,
        sessionCount: form.timings?.sessionCount || 0,
        roundsPlanned: form.timings?.roundsPlanned || 0,
      },
      stewarding: {
        decisionMode: (form.stewarding?.decisionMode as 'owner_only' | 'admin_vote' | 'steward_panel') || 'admin_only',
        requiredVotes: form.stewarding?.requiredVotes || 0,
        requireDefense: form.stewarding?.requireDefense ?? false,
        defenseTimeLimit: form.stewarding?.defenseTimeLimit || 0,
        voteTimeLimit: form.stewarding?.voteTimeLimit || 0,
        protestDeadlineHours: form.stewarding?.protestDeadlineHours || 0,
        stewardingClosesHours: form.stewarding?.stewardingClosesHours || 0,
        notifyAccusedOnProtest: form.stewarding?.notifyAccusedOnProtest ?? true,
        notifyOnVoteRequired: form.stewarding?.notifyOnVoteRequired ?? true,
      },
    };

    const allErrors = LeagueWizardCommandModel.validateAllLeagueWizardSteps(formData);
    setErrors((prev) => ({
      ...prev,
      ...allErrors,
    }));

    if (LeagueWizardCommandModel.hasWizardErrors(allErrors)) {
      handleStepChange('basics');
      return;
    }

    setLoading(true);
    setErrors((prev) => {
      const { submit: _, ...rest } = prev;
      return rest;
    });

    try {
      const result = await createLeagueMutation.mutateAsync({ form, ownerId });
      clearFormStorage();
      router.push(`/leagues/${result.leagueId}`);
    } catch (err) {
      const message = err instanceof Error ? err.message : 'Failed to create league';
      setErrors((prev) => ({
        ...prev,
        submit: message,
      }));
      setLoading(false);
    }
  };

  const handleScoringPresetChange = (patternId: string) => {
    setForm((prev) => {
      const selectedPreset = presets.find((p) => p.id === patternId);

      return {
        ...prev,
        scoring: {
          ...prev.scoring,
          patternId,
          customScoringEnabled: false,
        },
        timings: selectedPreset
          ? {
              ...prev.timings,
              practiceMinutes: prev.timings?.practiceMinutes ?? selectedPreset.defaultTimings.practiceMinutes,
              qualifyingMinutes: prev.timings?.qualifyingMinutes ?? selectedPreset.defaultTimings.qualifyingMinutes,
              sprintRaceMinutes: prev.timings?.sprintRaceMinutes ?? selectedPreset.defaultTimings.sprintRaceMinutes,
              mainRaceMinutes: prev.timings?.mainRaceMinutes ?? selectedPreset.defaultTimings.mainRaceMinutes,
              sessionCount: selectedPreset.defaultTimings.sessionCount,
            }
          : prev.timings,
      };
    });
  };
  
  const steps = [
    { id: 1 as Step, label: 'Basics', icon: FileText, shortLabel: 'Name' },
    { id: 2 as Step, label: 'Visibility', icon: Award, shortLabel: 'Type' },
    { id: 3 as Step, label: 'Structure', icon: Users, shortLabel: 'Mode' },
    { id: 4 as Step, label: 'Schedule', icon: Calendar, shortLabel: 'Time' },
    { id: 5 as Step, label: 'Scoring', icon: Trophy, shortLabel: 'Points' },
    { id: 6 as Step, label: 'Stewarding', icon: Scale, shortLabel: 'Rules' },
    { id: 7 as Step, label: 'Review', icon: CheckCircle2, shortLabel: 'Done' },
  ];

  const getStepTitle = (currentStep: Step): string => {
    switch (currentStep) {
      case 1: return 'Name your league';
      case 2: return 'Choose your destiny';
      case 3: return 'Choose the structure';
      case 4: return 'Set the schedule';
      case 5: return 'Scoring & championships';
      case 6: return 'Stewarding & protests';
      case 7: return 'Review & create';
      default: return '';
    }
  };

  const getStepSubtitle = (currentStep: Step): string => {
    switch (currentStep) {
      case 1: return 'Give your league a memorable name and tell your story.';
      case 2: return 'Will you compete for global rankings or race with friends?';
      case 3: return 'Define how races in this season will run.';
      case 4: return 'Plan when this season’s races happen.';
      case 5: return 'Choose how points and drop scores work for this season.';
      case 6: return 'Set how protests and stewarding work for this season.';
      case 7: return 'Review your league and first season before launching.';
      default: return '';
    }
  };

  const getStepContextLabel = (currentStep: Step): string => {
    if (currentStep === 1 || currentStep === 2) return 'League setup';
    if (currentStep >= 3 && currentStep <= 6) return 'Season setup';
    return 'League & Season summary';
  };

  return (
    <CreateLeagueWizardTemplate
      viewData={{}}
      step={step}
      steps={steps}
      form={form}
      errors={errors}
      loading={loading}
      presetsLoading={presetsLoading}
      presets={presets}
      highestCompletedStep={highestCompletedStep}
      onGoToStep={goToStep}
      onFormChange={setForm}
      onSubmit={handleSubmit}
      onNextStep={goToNextStep}
      onPreviousStep={goToPreviousStep}
      onScoringPresetChange={handleScoringPresetChange}
      onToggleCustomScoring={() =>
        setForm((prev) => ({
          ...prev,
          scoring: {
            ...prev.scoring,
            customScoringEnabled: !(prev.scoring?.customScoringEnabled),
          },
        }))
      }
      getStepTitle={getStepTitle}
      getStepSubtitle={getStepSubtitle}
      getStepContextLabel={getStepContextLabel}
    />
  );
}