import { create } from 'zustand';
import { persist } from 'zustand/middleware';
import {
  AgentProfileApiError,
  getAgentProfile,
  putAgentProfile,
  type AgentProfileRead,
  type AgentProfileUpdate,
} from '@/lib/agent-profile';

export type UserGender = 'male' | 'female' | 'other' | 'undisclosed';

export type UserProfileDraft = {
  displayName: string;
  age: number | null;
  gender: UserGender;
};

export type AgentUserProfile = UserProfileDraft & {
  shareAgeWithAgents: boolean;
  shareGenderWithAgents: boolean;
  analysisEnabled: boolean;
  pendingSync: boolean;
  version: number;
  updatedAt: string | null;
};

export type ProfileSyncStatus = 'idle' | 'loading' | 'ready' | 'saving' | 'error';

export type ProfileSyncState = {
  status: ProfileSyncStatus;
  error: string | null;
};

type UserProfileState = {
  profilesByUserId: Record<string, AgentUserProfile>;
  syncStatesByUserId: Record<string, ProfileSyncState>;
  saveProfile: (userId: string, profile: UserProfileDraft) => void;
  syncProfile: (userId: string, accessToken: string) => Promise<AgentUserProfile>;
  saveProfileToServer: (userId: string, accessToken: string) => Promise<AgentUserProfile>;
};

export const EMPTY_AGENT_USER_PROFILE: AgentUserProfile = {
  displayName: '',
  age: null,
  gender: 'undisclosed',
  shareAgeWithAgents: false,
  shareGenderWithAgents: false,
  analysisEnabled: true,
  pendingSync: false,
  version: 0,
  updatedAt: null,
};

const inFlightSyncRequests = new Map<string, Promise<AgentUserProfile>>();

export function getProfileAccountKey(userId: string | null | undefined): string | null {
  const value = userId?.trim();
  return value || null;
}

export function isUserProfileComplete(profile: AgentUserProfile | undefined): boolean {
  return Boolean(profile?.displayName.trim());
}

function fromServerProfile(profile: AgentProfileRead): AgentUserProfile {
  return {
    displayName: profile.display_name ?? '',
    age: profile.age,
    gender: profile.gender ?? 'undisclosed',
    shareAgeWithAgents: profile.share_age_with_agents,
    shareGenderWithAgents: profile.share_gender_with_agents,
    analysisEnabled: profile.analysis_enabled,
    pendingSync: false,
    version: profile.version,
    updatedAt: profile.updated_at,
  };
}

function toAgentProfileUpdate(profile: AgentUserProfile, version = profile.version): AgentProfileUpdate {
  const gender = profile.gender === 'undisclosed' ? null : profile.gender;
  return {
    display_name: profile.displayName.trim(),
    age: profile.age,
    gender,
    share_age_with_agents: profile.age !== null && (profile.shareAgeWithAgents ?? true),
    share_gender_with_agents: gender !== null && (profile.shareGenderWithAgents ?? true),
    analysis_enabled: profile.analysisEnabled ?? true,
    version,
  };
}

function getErrorMessage(error: unknown): string {
  if (error instanceof AgentProfileApiError) {
    if (error.status === 401) return '登录已过期，请重新登录后再同步个人资料。';
    if (error.status === 503) return '个人资料服务暂时不可用，请稍后重试。';
    return error.message;
  }
  return error instanceof Error ? error.message : String(error);
}

function buildLocalProfile(
  existing: AgentUserProfile | undefined,
  draft: UserProfileDraft,
): AgentUserProfile {
  const age = draft.age;
  const gender = draft.gender;
  const hadAge = typeof existing?.age === 'number';
  const hadGender = Boolean(existing && existing.gender !== 'undisclosed');

  return {
    ...(existing ?? EMPTY_AGENT_USER_PROFILE),
    displayName: draft.displayName.trim(),
    age,
    gender,
    shareAgeWithAgents: age !== null
      ? (hadAge ? (existing?.shareAgeWithAgents ?? true) : true)
      : false,
    shareGenderWithAgents: gender !== 'undisclosed'
      ? (hadGender ? (existing?.shareGenderWithAgents ?? true) : true)
      : false,
    pendingSync: true,
    version: existing?.version ?? 0,
    updatedAt: existing?.updatedAt ?? null,
  };
}

function profileSyncState(status: ProfileSyncStatus, error: string | null = null): ProfileSyncState {
  return { status, error };
}

export function buildAgentUserContext(profile: AgentUserProfile | undefined): string | null {
  if (!isUserProfileComplete(profile)) return null;
  const lines = [
    '## 当前用户资料',
    `当前与你协作的用户名字是「${profile!.displayName.trim()}」。`,
    `可以根据这份资料调整称呼、表达方式、解释深度和互动方式，但不要反复提及资料。`,
  ];
  if (profile!.age !== null && (profile!.shareAgeWithAgents ?? true)) {
    lines.push(`用户年龄：${profile!.age} 岁。`);
  }
  if (profile!.gender !== 'undisclosed' && (profile!.shareGenderWithAgents ?? true)) {
    const genderLabel = profile!.gender === 'male' ? '男' : profile!.gender === 'female' ? '女' : '其他';
    lines.push(`用户性别：${genderLabel}。`);
  }
  lines.push('不要根据年龄或性别推断用户的健康、能力、身份或其他敏感属性。');
  return lines.join('\n');
}

export const useUserProfileStore = create<UserProfileState>()(
  persist(
    (set, get) => ({
      profilesByUserId: {},
      syncStatesByUserId: {},
      saveProfile: (userId, profile) => set((state) => ({
        profilesByUserId: {
          ...state.profilesByUserId,
          [userId]: buildLocalProfile(state.profilesByUserId[userId], profile),
        },
        syncStatesByUserId: {
          ...state.syncStatesByUserId,
          [userId]: profileSyncState('idle'),
        },
      })),
      syncProfile: (userId, accessToken) => {
        const existingRequest = inFlightSyncRequests.get(userId);
        if (existingRequest) return existingRequest;

        const request = (async () => {
          set((state) => ({
            syncStatesByUserId: {
              ...state.syncStatesByUserId,
              [userId]: profileSyncState('loading'),
            },
          }));

          try {
            const server = await getAgentProfile(accessToken);
            const local = get().profilesByUserId[userId];

            if (server.version > 0) {
              const profile = fromServerProfile(server);
              set((state) => ({
                profilesByUserId: { ...state.profilesByUserId, [userId]: profile },
                syncStatesByUserId: {
                  ...state.syncStatesByUserId,
                  [userId]: profileSyncState('ready'),
                },
              }));
              return profile;
            }

            if (local && isUserProfileComplete(local)) {
              await putAgentProfile(accessToken, toAgentProfileUpdate(local, 0));
              const confirmed = fromServerProfile(await getAgentProfile(accessToken));
              set((state) => ({
                profilesByUserId: { ...state.profilesByUserId, [userId]: confirmed },
                syncStatesByUserId: {
                  ...state.syncStatesByUserId,
                  [userId]: profileSyncState('ready'),
                },
              }));
              return confirmed;
            }

            const profile = fromServerProfile(server);
            set((state) => ({
              profilesByUserId: { ...state.profilesByUserId, [userId]: profile },
              syncStatesByUserId: {
                ...state.syncStatesByUserId,
                [userId]: profileSyncState('ready'),
              },
            }));
            return profile;
          } catch (error) {
            set((state) => ({
              syncStatesByUserId: {
                ...state.syncStatesByUserId,
                [userId]: profileSyncState('error', getErrorMessage(error)),
              },
            }));
            throw error;
          }
        })();

        inFlightSyncRequests.set(userId, request);
        void request.then(
          () => {
            if (inFlightSyncRequests.get(userId) === request) inFlightSyncRequests.delete(userId);
          },
          () => {
            if (inFlightSyncRequests.get(userId) === request) inFlightSyncRequests.delete(userId);
          },
        );
        return request;
      },
      saveProfileToServer: async (userId, accessToken) => {
        const local = get().profilesByUserId[userId];
        if (!local) throw new Error('个人资料尚未加载');

        set((state) => ({
          syncStatesByUserId: {
            ...state.syncStatesByUserId,
            [userId]: profileSyncState('saving'),
          },
        }));

        try {
          const saved = fromServerProfile(await putAgentProfile(accessToken, toAgentProfileUpdate(local)));
          set((state) => ({
            profilesByUserId: { ...state.profilesByUserId, [userId]: saved },
            syncStatesByUserId: {
              ...state.syncStatesByUserId,
              [userId]: profileSyncState('ready'),
            },
          }));
          return saved;
        } catch (error) {
          if (error instanceof AgentProfileApiError && error.status === 409) {
            try {
              const latest = fromServerProfile(await getAgentProfile(accessToken));
              set((state) => ({
                profilesByUserId: { ...state.profilesByUserId, [userId]: latest },
                syncStatesByUserId: {
                  ...state.syncStatesByUserId,
                  [userId]: profileSyncState('ready'),
                },
              }));
            } catch (refreshError) {
              set((state) => ({
                syncStatesByUserId: {
                  ...state.syncStatesByUserId,
                  [userId]: profileSyncState('error', getErrorMessage(refreshError)),
                },
              }));
            }
          } else {
            set((state) => ({
              syncStatesByUserId: {
                ...state.syncStatesByUserId,
                [userId]: profileSyncState('error', getErrorMessage(error)),
              },
            }));
          }
          throw error;
        }
      },
    }),
    {
      name: 'niancode-user-agent-profiles',
      partialize: (state) => ({ profilesByUserId: state.profilesByUserId }),
    },
  ),
);