import type { ClassId } from "../app/characterCatalog";
import {
  abilitiesForClass,
  abilityAtLevel,
  type AbilityDefinition,
} from "./abilityCatalog";
import {
  actionBindingId,
  type ActionBindingControl,
} from "./actionBindings";
import { useCombatStore } from "./combatStore";
import { useGameStore } from "./store";

export const MANASTORM_ACTIVE_SPELL_LIMIT = 4;

export interface ManastormSpellLoadoutProvenance {
  readonly model: "local-client-spell-selection";
  readonly fidelity: "substitution";
  readonly exactServerParity: false;
  readonly source: "character-client-ability-catalog";
  readonly note: string;
}

export const MANASTORM_SPELL_LOADOUT_PROVENANCE: ManastormSpellLoadoutProvenance = Object.freeze({
  model: "local-client-spell-selection",
  fidelity: "substitution",
  exactServerParity: false,
  source: "character-client-ability-catalog",
  note: "The installed Manastorm client tables contain no authoritative spell-choice table; this local model selects from the character's imported client spell catalog.",
});

export interface ManastormActiveSpellOption {
  readonly id: string;
  readonly abilityId: string;
  readonly dbcSpellId: number;
  readonly name: string;
  readonly description: string;
  readonly icon: string;
  readonly unlockLevel: number;
  readonly source: NonNullable<AbilityDefinition["source"]>;
}

export interface ManastormActiveSpellLoadoutModel {
  readonly classId: ClassId;
  readonly characterLevel: number;
  readonly maxSelections: number;
  readonly options: readonly ManastormActiveSpellOption[];
  readonly provenance: ManastormSpellLoadoutProvenance;
}

export interface ManastormActiveSpellLoadoutRequest {
  readonly available: readonly ManastormActiveSpellOption[];
  readonly selectedIds: readonly string[];
  readonly maxSelections: number;
  readonly provenance: ManastormSpellLoadoutProvenance;
}

export interface ManastormActiveSpellLoadoutState extends ManastormActiveSpellLoadoutRequest {
  readonly selected: readonly ManastormActiveSpellOption[];
  readonly validationError: string | null;
}

export interface ManastormActiveSpellValidation {
  readonly ok: boolean;
  readonly selectedIds: readonly string[];
  readonly selected: readonly ManastormActiveSpellOption[];
  readonly error?: string;
}

const CLIENT_GROUNDED_SOURCES = new Set<AbilityDefinition["source"]>([
  "wow335-progression",
  "ascension-progression",
  "coa-starter",
  "coa-progression",
  "coa-tree",
]);

const PRIMARY_LOADOUT_CONTROLS: readonly ActionBindingControl[] = [
  "face-bottom",
  "face-left",
  "face-top",
  "face-right",
];

function learnedTalentRank(ability: AbilityDefinition, talentRanks: Readonly<Record<string, number>>): number {
  return ability.talentEntryId === undefined
    ? 0
    : Math.max(0, Math.trunc(talentRanks[`coa-entry-${ability.talentEntryId}`] ?? 0));
}

function isSelectableClientSpell(
  ability: AbilityDefinition,
  level: number,
  talentRanks: Readonly<Record<string, number>>,
): boolean {
  return !ability.passive
    && ability.unlockLevel <= level
    && CLIENT_GROUNDED_SOURCES.has(ability.source)
    && (ability.talentEntryId === undefined || learnedTalentRank(ability, talentRanks) > 0);
}

export function manastormActiveSpellLoadoutModel(
  classId: ClassId,
  characterLevel: number,
  talentRanks: Readonly<Record<string, number>> = {},
): ManastormActiveSpellLoadoutModel {
  const level = Math.max(1, Math.trunc(characterLevel));
  const options = abilitiesForClass(classId)
    .filter((ability) => isSelectableClientSpell(ability, level, talentRanks))
    .map((ability) => {
      const resolved = abilityAtLevel(ability, level, learnedTalentRank(ability, talentRanks));
      return Object.freeze({
        id: ability.id,
        abilityId: ability.id,
        dbcSpellId: resolved.dbcSpellId,
        name: resolved.name,
        description: resolved.description,
        icon: resolved.icon,
        unlockLevel: ability.unlockLevel,
        source: ability.source!,
      });
    })
    .sort((left, right) => (
      left.unlockLevel - right.unlockLevel
      || left.name.localeCompare(right.name)
      || left.dbcSpellId - right.dbcSpellId
    ));
  return Object.freeze({
    classId,
    characterLevel: level,
    maxSelections: MANASTORM_ACTIVE_SPELL_LIMIT,
    options: Object.freeze(options),
    provenance: MANASTORM_SPELL_LOADOUT_PROVENANCE,
  });
}

export function validateManastormActiveSpellLoadout(
  value: unknown,
  available: readonly ManastormActiveSpellOption[],
  maxSelections = MANASTORM_ACTIVE_SPELL_LIMIT,
): ManastormActiveSpellValidation {
  if (!Array.isArray(value)) {
    return Object.freeze({
      ok: false,
      selectedIds: Object.freeze([]),
      selected: Object.freeze([]),
      error: "Active-spell loadout must be a list.",
    });
  }
  const limit = Math.max(0, Math.trunc(maxSelections));
  if (value.length > limit) {
    return Object.freeze({
      ok: false,
      selectedIds: Object.freeze([]),
      selected: Object.freeze([]),
      error: `Select no more than ${limit} active spells.`,
    });
  }
  const byId = new Map(available.map((option) => [option.id, option]));
  const selected: ManastormActiveSpellOption[] = [];
  const ids: string[] = [];
  const seen = new Set<string>();
  for (const candidate of value) {
    if (typeof candidate !== "string" || !candidate.trim()) {
      return Object.freeze({
        ok: false,
        selectedIds: Object.freeze([]),
        selected: Object.freeze([]),
        error: "Active-spell loadout contains an invalid ID.",
      });
    }
    const id = candidate.trim();
    const option = byId.get(id);
    if (!option) {
      return Object.freeze({
        ok: false,
        selectedIds: Object.freeze([]),
        selected: Object.freeze([]),
        error: `${id} is not an available client-grounded spell for this character.`,
      });
    }
    if (seen.has(id)) {
      return Object.freeze({
        ok: false,
        selectedIds: Object.freeze([]),
        selected: Object.freeze([]),
        error: `${id} is selected more than once.`,
      });
    }
    seen.add(id);
    ids.push(id);
    selected.push(option);
  }
  return Object.freeze({
    ok: true,
    selectedIds: Object.freeze(ids),
    selected: Object.freeze(selected),
  });
}

export function resolveManastormActiveSpellLoadout(
  request?: ManastormActiveSpellLoadoutRequest,
): ManastormActiveSpellLoadoutState {
  if (!request) {
    return Object.freeze({
      available: Object.freeze([]),
      selectedIds: Object.freeze([]),
      selected: Object.freeze([]),
      maxSelections: MANASTORM_ACTIVE_SPELL_LIMIT,
      provenance: MANASTORM_SPELL_LOADOUT_PROVENANCE,
      validationError: null,
    });
  }
  const validation = validateManastormActiveSpellLoadout(
    request.selectedIds,
    request.available,
    request.maxSelections,
  );
  return Object.freeze({
    available: Object.freeze([...request.available]),
    selectedIds: validation.selectedIds,
    selected: validation.selected,
    maxSelections: Math.max(0, Math.trunc(request.maxSelections)),
    provenance: request.provenance,
    validationError: validation.error ?? null,
  });
}

/**
 * The server-side Manastorm grant/loadout table was not present in the client.
 * As a transparent local substitute, selected imported spells are pinned to
 * the first four base controls for the duration of the run.
 */
export function activateManastormActiveSpellLoadout(
  loadout: ManastormActiveSpellLoadoutState,
): boolean {
  if (useGameStore.getState().gameMode !== "manastorm") return false;
  const validation = validateManastormActiveSpellLoadout(
    loadout.selectedIds,
    loadout.available,
    loadout.maxSelections,
  );
  if (!validation.ok) return false;
  const combat = useCombatStore.getState();
  const abilityIds = new Set(combat.abilities.map((ability) => ability.id));
  if (validation.selectedIds.some((id) => !abilityIds.has(id))) return false;
  if (!validation.selectedIds.length) return true;
  const bindings = { ...combat.actionBindings };
  PRIMARY_LOADOUT_CONTROLS.forEach((control, index) => {
    bindings[actionBindingId("primary", control)] = validation.selectedIds[index] ?? null;
  });
  useCombatStore.setState({ actionBindings: bindings });
  return true;
}