import type {
  DirectedRuntimeReward,
  InventoryItem,
  RuntimeItemGenerationChannel,
  RuntimeItemGenerationContext,
  RuntimeItemKind,
  RuntimeItemPermanence,
  RuntimeItemPlan,
  RuntimeRelationAnchor,
} from '../types';
import {generateRuntimeItemAiIntents} from '../services/runtimeItemAiDirector';
import {compileRuntimeItem} from './runtimeItemCompiler';
import {
  applyRuntimeItemNarrative,
  buildRuntimeItemAiIntent,
  buildRuntimeRewardStoryHint,
  flattenDirectedRuntimeRewardItems,
} from './runtimeItemNarrative';

type RuntimeRewardOptions = {
  seedKey: string;
  variant?: string;
  itemCount?: number;
  fixedKinds?: RuntimeItemKind[];
  fixedPermanence?: RuntimeItemPermanence[];
  baseHp?: number;
  baseMana?: number;
  baseCurrency?: number;
  storyHint?: string;
};

const GAP_TO_TAGS: Record<string, string[]> = {
  survival_gap: ['守御', '护体', '回复', '续战'],
  mana_gap: ['法力', '冷却', '过载'],
  finisher_gap: ['爆发', '重击', '追击'],
  mobility_gap: ['突进', '快袭', '风行', '游击'],
  control_gap: ['控场', '符阵', '镇邪'],
};

function hashText(value: string) {
  let hash = 0;
  for (let index = 0; index < value.length; index += 1) {
    hash = ((hash << 5) - hash) + value.charCodeAt(index);
    hash |= 0;
  }
  return Math.abs(hash);
}

function resolveGapDrivenTags(context: RuntimeItemGenerationContext) {
  const gapTags = context.playerBuildGaps.flatMap(gap => GAP_TO_TAGS[gap] ?? []);
  return [...new Set([
    ...gapTags,
    ...context.playerBuildTags,
  ])].slice(0, 3);
}

function resolveRelationAnchor(context: RuntimeItemGenerationContext): RuntimeRelationAnchor {
  if (context.encounter?.monsterPresetId) {
    return {
      type: 'monster',
      monsterId: context.encounter.monsterPresetId,
      monsterName: context.encounter.npcName,
    };
  }

  if (context.encounterNpcName) {
    return {
      type: 'npc',
      npcId: context.encounterNpcId ?? undefined,
      npcName: context.encounterNpcName,
      roleText: context.encounterContextText ?? undefined,
    };
  }

  if (context.sceneName) {
    return {
      type: 'scene',
      sceneId: context.sceneId ?? undefined,
      sceneName: context.sceneName,
    };
  }

  return {
    type: 'landmark',
    landmarkName: context.customWorldProfile?.name ?? '无名之地',
  };
}

function getChannelTemplate(channel: RuntimeItemGenerationChannel) {
  switch (channel) {
    case 'treasure':
      return {
        kinds: ['relic', 'consumable', 'material'] as RuntimeItemKind[],
        permanence: ['permanent', 'timed', 'resource'] as RuntimeItemPermanence[],
        defaultCount: 2,
      };
    case 'npc_trade':
      return {
        kinds: ['consumable', 'material', 'relic', 'equipment'] as RuntimeItemKind[],
        permanence: ['timed', 'resource', 'permanent', 'permanent'] as RuntimeItemPermanence[],
        defaultCount: 4,
      };
    case 'npc_reward':
      return {
        kinds: ['consumable', 'relic', 'equipment'] as RuntimeItemKind[],
        permanence: ['timed', 'permanent', 'permanent'] as RuntimeItemPermanence[],
        defaultCount: 1,
      };
    case 'monster_drop':
      return {
        kinds: ['material', 'consumable', 'relic'] as RuntimeItemKind[],
        permanence: ['resource', 'timed', 'permanent'] as RuntimeItemPermanence[],
        defaultCount: 2,
      };
    case 'quest_reward':
      return {
        kinds: ['equipment', 'relic', 'consumable'] as RuntimeItemKind[],
        permanence: ['permanent', 'permanent', 'timed'] as RuntimeItemPermanence[],
        defaultCount: 2,
      };
    default:
      return {
        kinds: ['consumable', 'material', 'relic'] as RuntimeItemKind[],
        permanence: ['timed', 'resource', 'permanent'] as RuntimeItemPermanence[],
        defaultCount: 2,
      };
  }
}

function planRuntimeItems(
  context: RuntimeItemGenerationContext,
  options: RuntimeRewardOptions,
): RuntimeItemPlan[] {
  const template = getChannelTemplate(context.generationChannel);
  const count = Math.max(1, options.itemCount ?? template.defaultCount);
  const relationAnchor = resolveRelationAnchor(context);
  const targetBuildDirection = resolveGapDrivenTags(context);
  const seed = hashText(`${options.seedKey}:${options.variant ?? 'default'}:${context.generationChannel}`);

  return Array.from({length: count}, (_, index) => {
    const kinds = options.fixedKinds?.length ? options.fixedKinds : template.kinds;
    const permanences = options.fixedPermanence?.length ? options.fixedPermanence : template.permanence;
    const itemKind = kinds[(seed + index) % kinds.length] ?? 'consumable';
    const permanence = permanences[(seed + index) % permanences.length] ?? 'timed';

    return {
      slot: index === 0 ? 'primary' : index === 1 ? 'secondary' : 'support',
      itemKind,
      permanence,
      narrativeWeight: index === 0 ? 'heavy' : 'medium',
      targetBuildDirection: targetBuildDirection.length > 0 ? targetBuildDirection : ['均衡'],
      relationAnchor,
    } satisfies RuntimeItemPlan;
  });
}

function compilePlannedItem(
  context: RuntimeItemGenerationContext,
  plan: RuntimeItemPlan,
  seedKey: string,
  intentOverride?: ReturnType<typeof buildRuntimeItemAiIntent>,
) {
  const intent = intentOverride ?? buildRuntimeItemAiIntent(context, plan);
  const compiled = compileRuntimeItem({
    seedKey,
    context,
    plan,
    intent,
  });

  return applyRuntimeItemNarrative({
    item: compiled,
    context,
    plan,
    intent,
  });
}

function buildDirectedRewardFromItems(
  compiledItems: InventoryItem[],
  options: RuntimeRewardOptions,
): DirectedRuntimeReward {
  const reward: DirectedRuntimeReward = {
    primaryItem: compiledItems[0] ?? null,
    supportItems: compiledItems.slice(1),
    hp: options.baseHp,
    mana: options.baseMana,
    currency: options.baseCurrency,
    storyHint: options.storyHint,
  };

  return {
    ...reward,
    storyHint: buildRuntimeRewardStoryHint(reward),
  };
}

export function buildDirectedRuntimeReward(
  context: RuntimeItemGenerationContext,
  options: RuntimeRewardOptions,
): DirectedRuntimeReward {
  const plans = planRuntimeItems(context, options);
  const compiledItems = plans.map((plan, index) =>
    compilePlannedItem(context, plan, `${options.seedKey}:${plan.slot}:${index}`),
  );

  return buildDirectedRewardFromItems(compiledItems, options);
}

export async function generateDirectedRuntimeReward(
  context: RuntimeItemGenerationContext,
  options: RuntimeRewardOptions,
): Promise<DirectedRuntimeReward> {
  const plans = planRuntimeItems(context, options);

  try {
    const aiIntents = await generateRuntimeItemAiIntents({
      context,
      plans,
    });
    const compiledItems = plans.map((plan, index) =>
      compilePlannedItem(
        context,
        plan,
        `${options.seedKey}:${plan.slot}:${index}`,
        aiIntents[index],
      ),
    );

    return buildDirectedRewardFromItems(compiledItems, options);
  } catch (error) {
    console.warn('[RuntimeItemDirector] falling back to deterministic item intent', error);
    return buildDirectedRuntimeReward(context, options);
  }
}

export function buildRuntimeInventoryStock(
  context: RuntimeItemGenerationContext,
  options: RuntimeRewardOptions,
): InventoryItem[] {
  return flattenDirectedRuntimeRewardItems(buildDirectedRuntimeReward(context, options));
}