import {
  PHENOLOGY_PHASES,
  type PhenologyPhaseKey,
} from '../../season/season-types';
import {
  bool,
  childScope,
  enumList,
  enumValue,
  has,
  isCleared,
  makeParser,
  monthDay,
  numberIn,
  report,
  type Scope,
} from './parse-helpers';
import type { PhenologyConfig } from './rule-config.types';

/** Upper limit of a growing-degree-day threshold; far above any phase. */
const MAX_GTS_THRESHOLD = 5000;
const MAX_GAP_SHARE = 0.5;

export const DEFAULT_PHENOLOGY_CONFIG: PhenologyConfig = {
  useGts: true,
  gtsThresholds: { SALWEIDE: 200 },
  calibrateFromReports: true,
  calibratePhases: ['KIRSCHE', 'APFEL'],
  calendarFallback: {
    SALWEIDE: '03-20',
    KIRSCHE: '04-15',
    APFEL: '04-28',
    HOLUNDER: '05-30',
    LINDE: '06-20',
    TRACHTENDE: '08-01',
    HERBST: '09-15',
    WINTER: '11-15',
  },
  swarmSeason: { from: 'KIRSCHE', until: 'LINDE' },
  maxGapShare: 0.1,
};

function readThresholds(scope: Scope): PhenologyConfig['gtsThresholds'] {
  // Without the group the defaults apply; with it, only the phases given
  // have a threshold - leaving one out removes it.
  if (!has(scope, 'gtsThresholds')) {
    return { ...DEFAULT_PHENOLOGY_CONFIG.gtsThresholds };
  }
  const thresholds = childScope(scope, 'gtsThresholds');
  const result: PhenologyConfig['gtsThresholds'] = {};
  for (const phase of PHENOLOGY_PHASES) {
    if (isCleared(thresholds, phase)) {
      continue;
    }
    const value = numberIn(
      thresholds,
      phase,
      Number.NaN,
      0,
      MAX_GTS_THRESHOLD,
      { exclusiveMin: true },
    );
    if (!Number.isNaN(value)) {
      result[phase] = value;
    }
  }
  return result;
}

/**
 * The calendar dates of the phases must not run backwards in phase order.
 * One violation sends the whole map back to the defaults, so it stays
 * consistent; the issue names a key the caller actually sent.
 */
function readCalendar(scope: Scope): PhenologyConfig['calendarFallback'] {
  const calendar = childScope(scope, 'calendarFallback');
  const defaults = DEFAULT_PHENOLOGY_CONFIG.calendarFallback;
  const before = scope.issues.length;
  const result = { ...defaults };
  for (const phase of PHENOLOGY_PHASES) {
    result[phase] = monthDay(calendar, phase, defaults[phase]);
  }
  if (scope.issues.length > before) {
    return { ...defaults };
  }
  for (let index = 1; index < PHENOLOGY_PHASES.length; index += 1) {
    const previous = PHENOLOGY_PHASES[index - 1];
    const phase = PHENOLOGY_PHASES[index];
    if (result[phase] < result[previous]) {
      const culprit = has(calendar, phase) ? phase : previous;
      report(
        calendar,
        culprit,
        `Das Datum darf nicht vor dem der vorherigen Phase liegen (${previous}).`,
      );
      return { ...defaults };
    }
  }
  return result;
}

function readSwarmSeason(scope: Scope): PhenologyConfig['swarmSeason'] {
  const season = childScope(scope, 'swarmSeason');
  const defaults = DEFAULT_PHENOLOGY_CONFIG.swarmSeason;
  const from: PhenologyPhaseKey = enumValue(
    season,
    'from',
    defaults.from,
    PHENOLOGY_PHASES,
  );
  const until: PhenologyPhaseKey = enumValue(
    season,
    'until',
    defaults.until,
    PHENOLOGY_PHASES,
  );
  if (PHENOLOGY_PHASES.indexOf(from) >= PHENOLOGY_PHASES.indexOf(until)) {
    report(
      season,
      has(season, 'from') ? 'from' : 'until',
      'Der Beginn der Schwarmzeit muss vor ihrem Ende liegen.',
    );
    return { ...defaults };
  }
  return { from, until };
}

export const phenologyParser = makeParser<PhenologyConfig>(
  'PHENOLOGY',
  DEFAULT_PHENOLOGY_CONFIG,
  (scope) => {
    const d = DEFAULT_PHENOLOGY_CONFIG;
    return {
      useGts: bool(scope, 'useGts', d.useGts),
      gtsThresholds: readThresholds(scope),
      calibrateFromReports: bool(
        scope,
        'calibrateFromReports',
        d.calibrateFromReports,
      ),
      calibratePhases: enumList(
        scope,
        'calibratePhases',
        d.calibratePhases,
        PHENOLOGY_PHASES,
      ),
      calendarFallback: readCalendar(scope),
      swarmSeason: readSwarmSeason(scope),
      maxGapShare: numberIn(
        scope,
        'maxGapShare',
        d.maxGapShare,
        0,
        MAX_GAP_SHARE,
      ),
    };
  },
);