'use client';

import { useEffect, useState, FormEvent } from 'react';
import { useRouter } from 'next/navigation';
import {
  FileText,
  Users,
  Calendar,
  Trophy,
  Award,
  CheckCircle2,
  ChevronLeft,
  ChevronRight,
  Loader2,
  AlertCircle,
  Sparkles,
  Check,
} from 'lucide-react';
import Card from '@/components/ui/Card';
import Button from '@/components/ui/Button';
import Heading from '@/components/ui/Heading';
import LeagueReviewSummary from '@/components/leagues/LeagueReviewSummary';
import {
  getDriverRepository,
  getListLeagueScoringPresetsQuery,
  getCreateLeagueWithSeasonAndScoringUseCase,
} from '@/lib/di-container';
import type { LeagueScoringPresetDTO } from '@gridpilot/racing/application/ports/LeagueScoringPresetProvider';
import type { LeagueConfigFormModel } from '@gridpilot/racing/application';
import { LeagueBasicsSection } from './LeagueBasicsSection';
import { LeagueStructureSection } from './LeagueStructureSection';
import {
  LeagueScoringSection,
  ScoringPatternSection,
  ChampionshipsSection,
} from './LeagueScoringSection';
import { LeagueDropSection } from './LeagueDropSection';
import { LeagueTimingsSection } from './LeagueTimingsSection';

type Step = 1 | 2 | 3 | 4 | 5;

interface WizardErrors {
  basics?: {
    name?: string;
    visibility?: string;
  };
  structure?: {
    maxDrivers?: string;
    maxTeams?: string;
    driversPerTeam?: string;
  };
  timings?: {
    qualifyingMinutes?: string;
    mainRaceMinutes?: string;
    roundsPlanned?: string;
  };
  scoring?: {
    patternId?: string;
  };
  submit?: string;
}

function createDefaultForm(): LeagueConfigFormModel {
  const defaultPatternId = 'sprint-main-driver';

  return {
    basics: {
      name: '',
      description: '',
      visibility: 'public',
      gameId: 'iracing',
    },
    structure: {
      mode: 'solo',
      maxDrivers: 24,
      maxTeams: undefined,
      driversPerTeam: undefined,
      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: defaultPatternId === 'sprint-main-driver' ? 20 : undefined,
      mainRaceMinutes: 40,
      sessionCount: 2,
      roundsPlanned: 8,
    },
  };
}

export default function CreateLeagueWizard() {
  const router = useRouter();
 
  const [step, setStep] = useState<Step>(1);
  const [loading, setLoading] = useState(false);
  const [presetsLoading, setPresetsLoading] = useState(true);
  const [presets, setPresets] = useState<LeagueScoringPresetDTO[]>([]);
  const [errors, setErrors] = useState<WizardErrors>({});
  const [form, setForm] = useState<LeagueConfigFormModel>(() =>
    createDefaultForm(),
  );

  useEffect(() => {
    async function loadPresets() {
      try {
        const query = getListLeagueScoringPresetsQuery();
        const result = await query.execute();
        setPresets(result);
        if (result.length > 0) {
          setForm((prev) => ({
            ...prev,
            scoring: {
              ...prev.scoring,
              patternId: prev.scoring.patternId || result[0].id,
              customScoringEnabled: prev.scoring.customScoringEnabled ?? false,
            },
          }));
        }
      } catch (err) {
        setErrors((prev) => ({
          ...prev,
          submit:
            err instanceof Error
              ? err.message
              : 'Failed to load scoring presets',
        }));
      } finally {
        setPresetsLoading(false);
      }
    }

    loadPresets();
  }, []);

  const validateStep = (currentStep: Step): boolean => {
    const nextErrors: WizardErrors = {};

    if (currentStep === 1) {
      const basicsErrors: WizardErrors['basics'] = {};
      if (!form.basics.name.trim()) {
        basicsErrors.name = 'Name is required';
      }
      if (!form.basics.visibility) {
        basicsErrors.visibility = 'Visibility is required';
      }
      if (Object.keys(basicsErrors).length > 0) {
        nextErrors.basics = basicsErrors;
      }
    }

    if (currentStep === 2) {
      const structureErrors: WizardErrors['structure'] = {};
      if (form.structure.mode === 'solo') {
        if (!form.structure.maxDrivers || form.structure.maxDrivers <= 0) {
          structureErrors.maxDrivers =
            'Max drivers must be greater than 0 for solo leagues';
        }
      } else if (form.structure.mode === 'fixedTeams') {
        if (
          !form.structure.maxTeams ||
          form.structure.maxTeams <= 0
        ) {
          structureErrors.maxTeams =
            'Max teams must be greater than 0 for team leagues';
        }
        if (
          !form.structure.driversPerTeam ||
          form.structure.driversPerTeam <= 0
        ) {
          structureErrors.driversPerTeam =
            'Drivers per team must be greater than 0';
        }
      }
      if (Object.keys(structureErrors).length > 0) {
        nextErrors.structure = structureErrors;
      }
    }

    if (currentStep === 3) {
      const timingsErrors: WizardErrors['timings'] = {};
      if (!form.timings.qualifyingMinutes || form.timings.qualifyingMinutes <= 0) {
        timingsErrors.qualifyingMinutes =
          'Qualifying duration must be greater than 0 minutes';
      }
      if (!form.timings.mainRaceMinutes || form.timings.mainRaceMinutes <= 0) {
        timingsErrors.mainRaceMinutes =
          'Main race duration must be greater than 0 minutes';
      }
      if (Object.keys(timingsErrors).length > 0) {
        nextErrors.timings = timingsErrors;
      }
    }

    if (currentStep === 4) {
      const scoringErrors: WizardErrors['scoring'] = {};
      if (!form.scoring.patternId && !form.scoring.customScoringEnabled) {
        scoringErrors.patternId =
          'Select a scoring preset or enable custom scoring';
      }
      if (Object.keys(scoringErrors).length > 0) {
        nextErrors.scoring = scoringErrors;
      }
    }

    setErrors((prev) => ({
      ...prev,
      ...nextErrors,
    }));

    return Object.keys(nextErrors).length === 0;
  };

  const goToNextStep = () => {
    if (!validateStep(step)) {
      return;
    }
    setStep((prev) => (prev < 5 ? ((prev + 1) as Step) : prev));
  };

  const goToPreviousStep = () => {
    setStep((prev) => (prev > 1 ? ((prev - 1) as Step) : prev));
  };

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

    if (
      !validateStep(1) ||
      !validateStep(2) ||
      !validateStep(3) ||
      !validateStep(4)
    ) {
      setStep(1);
      return;
    }

    setLoading(true);
    setErrors((prev) => ({ ...prev, submit: undefined }));

    try {
      const driverRepo = getDriverRepository();
      const drivers = await driverRepo.findAll();
      const currentDriver = drivers[0];

      if (!currentDriver) {
        setErrors((prev) => ({
          ...prev,
          submit:
            'No driver profile found. Please create a driver profile first.',
        }));
        setLoading(false);
        return;
      }

      const createUseCase = getCreateLeagueWithSeasonAndScoringUseCase();

      const structure = form.structure;
      let maxDrivers: number | undefined;
      let maxTeams: number | undefined;

      if (structure.mode === 'solo') {
        maxDrivers =
          typeof structure.maxDrivers === 'number'
            ? structure.maxDrivers
            : undefined;
        maxTeams = undefined;
      } else {
        const teams =
          typeof structure.maxTeams === 'number' ? structure.maxTeams : 0;
        const perTeam =
          typeof structure.driversPerTeam === 'number'
            ? structure.driversPerTeam
            : 0;
        maxTeams = teams > 0 ? teams : undefined;
        maxDrivers =
          teams > 0 && perTeam > 0 ? teams * perTeam : undefined;
      }

      const command = {
        name: form.basics.name.trim(),
        description: form.basics.description?.trim() || undefined,
        visibility: form.basics.visibility,
        ownerId: currentDriver.id,
        gameId: form.basics.gameId,
        maxDrivers,
        maxTeams,
        enableDriverChampionship: form.championships.enableDriverChampionship,
        enableTeamChampionship: form.championships.enableTeamChampionship,
        enableNationsChampionship:
          form.championships.enableNationsChampionship,
        enableTrophyChampionship:
          form.championships.enableTrophyChampionship,
        scoringPresetId: form.scoring.patternId || undefined,
      } as const;

      const result = await createUseCase.execute(command);

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

  const currentPreset =
    presets.find((p) => p.id === form.scoring.patternId) ?? null;

  // Handler for scoring preset selection - updates timing defaults based on preset
  const handleScoringPresetChange = (patternId: string) => {
    const lowerPresetId = patternId.toLowerCase();
    
    setForm((prev) => {
      const timings = prev.timings ?? {};
      let updatedTimings = { ...timings };
      
      // Auto-configure session durations based on preset type
      if (lowerPresetId.includes('sprint') || lowerPresetId.includes('double')) {
        updatedTimings = {
          ...updatedTimings,
          practiceMinutes: 15,
          qualifyingMinutes: 20,
          sprintRaceMinutes: 20,
          mainRaceMinutes: 35,
          sessionCount: 2,
        };
      } else if (lowerPresetId.includes('endurance') || lowerPresetId.includes('long')) {
        updatedTimings = {
          ...updatedTimings,
          practiceMinutes: 30,
          qualifyingMinutes: 30,
          sprintRaceMinutes: undefined,
          mainRaceMinutes: 90,
          sessionCount: 1,
        };
      } else {
        // Standard/feature format
        updatedTimings = {
          ...updatedTimings,
          practiceMinutes: 20,
          qualifyingMinutes: 30,
          sprintRaceMinutes: undefined,
          mainRaceMinutes: 40,
          sessionCount: 1,
        };
      }
      
      return {
        ...prev,
        scoring: {
          ...prev.scoring,
          patternId,
          customScoringEnabled: false,
        },
        timings: updatedTimings,
      };
    });
  };
 
  const steps = [
    { id: 1 as Step, label: 'Basics', icon: FileText, shortLabel: 'Name' },
    { id: 2 as Step, label: 'Structure', icon: Users, shortLabel: 'Mode' },
    { id: 3 as Step, label: 'Schedule', icon: Calendar, shortLabel: 'Time' },
    { id: 4 as Step, label: 'Scoring', icon: Trophy, shortLabel: 'Points' },
    { id: 5 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 the structure';
      case 3:
        return 'Set the schedule';
      case 4:
        return 'Scoring & championships';
      case 5:
        return 'Review & create';
      default:
        return '';
    }
  };

  const getStepSubtitle = (currentStep: Step): string => {
    switch (currentStep) {
      case 1:
        return 'Give your league a memorable name and choose who can join.';
      case 2:
        return 'Will drivers compete individually or as part of teams?';
      case 3:
        return 'Configure session durations and plan your season calendar.';
      case 4:
        return 'Select a scoring preset, enable championships, and set drop rules.';
      case 5:
        return 'Everything looks good? Launch your new league!';
      default:
        return '';
    }
  };

  const currentStepData = steps.find((s) => s.id === step);
  const CurrentStepIcon = currentStepData?.icon ?? FileText;

  return (
    <form onSubmit={handleSubmit} className="max-w-4xl mx-auto pb-8">
      {/* Header with icon */}
      <div className="mb-8">
        <div className="flex items-center gap-3 mb-3">
          <div className="flex h-11 w-11 items-center justify-center rounded-xl bg-gradient-to-br from-primary-blue/20 to-primary-blue/5 border border-primary-blue/20">
            <Sparkles className="w-5 h-5 text-primary-blue" />
          </div>
          <div>
            <Heading level={1} className="text-2xl sm:text-3xl">
              Create a new league
            </Heading>
            <p className="text-sm text-gray-500">
              Set up your racing series in {steps.length} easy steps
            </p>
          </div>
        </div>
      </div>

      {/* Desktop Progress Bar */}
      <div className="hidden md:block mb-8">
        <div className="relative">
          {/* Background track */}
          <div className="absolute top-5 left-6 right-6 h-0.5 bg-charcoal-outline rounded-full" />
          {/* Progress fill */}
          <div
            className="absolute top-5 left-6 h-0.5 bg-gradient-to-r from-primary-blue to-neon-aqua rounded-full transition-all duration-500 ease-out"
            style={{ width: `calc(${((step - 1) / (steps.length - 1)) * 100}% - 48px)` }}
          />

          <div className="relative flex justify-between">
            {steps.map((wizardStep) => {
              const isCompleted = wizardStep.id < step;
              const isCurrent = wizardStep.id === step;
              const StepIcon = wizardStep.icon;

              return (
                <div key={wizardStep.id} className="flex flex-col items-center">
                  <div
                    className={`
                      relative z-10 flex h-10 w-10 items-center justify-center rounded-full
                      transition-all duration-300 ease-out
                      ${isCurrent
                        ? 'bg-primary-blue text-white shadow-[0_0_24px_rgba(25,140,255,0.5)] scale-110'
                        : isCompleted
                        ? 'bg-primary-blue text-white'
                        : 'bg-iron-gray text-gray-500 border-2 border-charcoal-outline'
                      }
                    `}
                  >
                    {isCompleted ? (
                      <Check className="w-4 h-4" strokeWidth={3} />
                    ) : (
                      <StepIcon className="w-4 h-4" />
                    )}
                  </div>
                  <div className="mt-2 text-center">
                    <p
                      className={`text-xs font-medium transition-colors duration-200 ${
                        isCurrent
                          ? 'text-white'
                          : isCompleted
                          ? 'text-primary-blue'
                          : 'text-gray-500'
                      }`}
                    >
                      {wizardStep.label}
                    </p>
                  </div>
                </div>
              );
            })}
          </div>
        </div>
      </div>

      {/* Mobile Progress */}
      <div className="md:hidden mb-6">
        <div className="flex items-center justify-between mb-2">
          <div className="flex items-center gap-2">
            <CurrentStepIcon className="w-4 h-4 text-primary-blue" />
            <span className="text-sm font-medium text-white">{currentStepData?.label}</span>
          </div>
          <span className="text-xs text-gray-500">
            {step}/{steps.length}
          </span>
        </div>
        <div className="h-1.5 bg-charcoal-outline rounded-full overflow-hidden">
          <div
            className="h-full bg-gradient-to-r from-primary-blue to-neon-aqua rounded-full transition-all duration-500 ease-out"
            style={{ width: `${(step / steps.length) * 100}%` }}
          />
        </div>
        {/* Step dots */}
        <div className="flex justify-between mt-2 px-0.5">
          {steps.map((s) => (
            <div
              key={s.id}
              className={`
                h-1.5 rounded-full transition-all duration-300
                ${s.id === step
                  ? 'w-4 bg-primary-blue'
                  : s.id < step
                  ? 'w-1.5 bg-primary-blue/60'
                  : 'w-1.5 bg-charcoal-outline'
                }
              `}
            />
          ))}
        </div>
      </div>

      {/* Main Card */}
      <Card className="relative overflow-hidden">
        {/* Top gradient accent */}
        <div className="absolute top-0 left-0 right-0 h-1 bg-gradient-to-r from-transparent via-primary-blue to-transparent" />

        {/* Step header */}
        <div className="flex items-start gap-4 mb-6">
          <div className="flex h-12 w-12 items-center justify-center rounded-xl bg-primary-blue/10 shrink-0 transition-transform duration-300">
            <CurrentStepIcon className="w-6 h-6 text-primary-blue" />
          </div>
          <div className="flex-1 min-w-0">
            <Heading level={2} className="text-xl sm:text-2xl text-white leading-tight">
              {getStepTitle(step)}
            </Heading>
            <p className="text-sm text-gray-400 mt-1">
              {getStepSubtitle(step)}
            </p>
          </div>
          <div className="hidden sm:flex items-center gap-1.5 px-3 py-1.5 rounded-full bg-deep-graphite border border-charcoal-outline">
            <span className="text-xs text-gray-500">Step</span>
            <span className="text-sm font-semibold text-white">{step}</span>
            <span className="text-xs text-gray-500">/ {steps.length}</span>
          </div>
        </div>

        {/* Divider */}
        <div className="h-px bg-gradient-to-r from-transparent via-charcoal-outline to-transparent mb-6" />

        {/* Step content with min-height for consistency */}
        <div className="min-h-[320px]">
          {step === 1 && (
            <div className="animate-fade-in">
              <LeagueBasicsSection
                form={form}
                onChange={setForm}
                errors={errors.basics}
              />
            </div>
          )}

          {step === 2 && (
            <div className="animate-fade-in">
              <LeagueStructureSection
                form={form}
                onChange={setForm}
                readOnly={false}
              />
            </div>
          )}

          {step === 3 && (
            <div className="animate-fade-in">
              <LeagueTimingsSection
                form={form}
                onChange={setForm}
                errors={errors.timings}
              />
            </div>
          )}

          {step === 4 && (
            <div className="animate-fade-in space-y-8">
              {/* Scoring Pattern Selection */}
              <ScoringPatternSection
                scoring={form.scoring}
                presets={presets}
                readOnly={presetsLoading}
                patternError={errors.scoring?.patternId}
                onChangePatternId={handleScoringPresetChange}
                onToggleCustomScoring={() =>
                  setForm((prev) => ({
                    ...prev,
                    scoring: {
                      ...prev.scoring,
                      customScoringEnabled: !prev.scoring.customScoringEnabled,
                    },
                  }))
                }
              />

              {/* Divider */}
              <div className="h-px bg-gradient-to-r from-transparent via-charcoal-outline to-transparent" />
              
              {/* Championships & Drop Rules side by side on larger screens */}
              <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
                <ChampionshipsSection form={form} onChange={setForm} readOnly={presetsLoading} />
                <LeagueDropSection form={form} onChange={setForm} readOnly={false} />
              </div>

              {errors.submit && (
                <div className="flex items-start gap-3 rounded-lg bg-warning-amber/10 p-4 border border-warning-amber/20">
                  <AlertCircle className="w-5 h-5 text-warning-amber shrink-0 mt-0.5" />
                  <p className="text-sm text-warning-amber">{errors.submit}</p>
                </div>
              )}
            </div>
          )}

          {step === 5 && (
            <div className="animate-fade-in space-y-6">
              <LeagueReviewSummary form={form} presets={presets} />
              {errors.submit && (
                <div className="flex items-start gap-3 rounded-lg bg-warning-amber/10 p-4 border border-warning-amber/20">
                  <AlertCircle className="w-5 h-5 text-warning-amber shrink-0 mt-0.5" />
                  <p className="text-sm text-warning-amber">{errors.submit}</p>
                </div>
              )}
            </div>
          )}
        </div>
      </Card>

      {/* Navigation */}
      <div className="flex justify-between items-center mt-6">
        <Button
          type="button"
          variant="secondary"
          disabled={step === 1 || loading}
          onClick={goToPreviousStep}
          className="flex items-center gap-2"
        >
          <ChevronLeft className="w-4 h-4" />
          <span className="hidden sm:inline">Back</span>
        </Button>

        <div className="flex items-center gap-3">
          {/* Mobile step dots */}
          <div className="flex sm:hidden items-center gap-1">
            {steps.map((s) => (
              <div
                key={s.id}
                className={`
                  h-1.5 rounded-full transition-all duration-300
                  ${s.id === step ? 'w-3 bg-primary-blue' : s.id < step ? 'w-1.5 bg-primary-blue/50' : 'w-1.5 bg-charcoal-outline'}
                `}
              />
            ))}
          </div>

          {step < 5 ? (
            <Button
              type="button"
              variant="primary"
              disabled={loading}
              onClick={goToNextStep}
              className="flex items-center gap-2"
            >
              <span>Continue</span>
              <ChevronRight className="w-4 h-4" />
            </Button>
          ) : (
            <Button
              type="submit"
              variant="primary"
              disabled={loading}
              className="flex items-center gap-2 min-w-[150px] justify-center"
            >
              {loading ? (
                <>
                  <Loader2 className="w-4 h-4 animate-spin" />
                  <span>Creating…</span>
                </>
              ) : (
                <>
                  <Sparkles className="w-4 h-4" />
                  <span>Create League</span>
                </>
              )}
            </Button>
          )}
        </div>
      </div>

      {/* Helper text */}
      <p className="text-center text-xs text-gray-500 mt-4">
        You can edit all settings after creating your league
      </p>
    </form>
  );
}