import type {
  AppUser,
  Company,
  Connection,
  Contact,
  DirectoryUser,
  Employment,
  HistoryEntry,
  Interview,
  Lead,
  LeadTodo,
  PerincoContact,
  Project,
  Tender,
} from '../types';

const TOKEN_KEY = 'icon_crm_token';

export function getToken(): string | null {
  return localStorage.getItem(TOKEN_KEY);
}
export function setToken(token: string) {
  localStorage.setItem(TOKEN_KEY, token);
}
export function clearToken() {
  localStorage.removeItem(TOKEN_KEY);
}

export class ApiError extends Error {
  status: number;
  constructor(message: string, status: number) {
    super(message);
    this.status = status;
  }
}

/** Wird bei 401 gefeuert, damit die Anwendung zurueck auf den Login springt. */
let onUnauthorized: (() => void) | null = null;
export function setUnauthorizedHandler(handler: (() => void) | null) {
  onUnauthorized = handler;
}

export async function apiRequest<T>(path: string, options: RequestInit = {}): Promise<T> {
  const headers = new Headers(options.headers);
  if (options.body && !headers.has('Content-Type') && !(options.body instanceof FormData)) {
    headers.set('Content-Type', 'application/json');
  }
  const token = getToken();
  if (token) headers.set('Authorization', `Bearer ${token}`);

  let response: Response;
  try {
    response = await fetch(`/api${path}`, { ...options, headers });
  } catch {
    throw new ApiError('Server nicht erreichbar. Bitte Verbindung prüfen.', 0);
  }

  if (response.status === 401) {
    clearToken();
    onUnauthorized?.();
  }

  const isJson = response.headers.get('content-type')?.includes('application/json');
  const payload = isJson ? await response.json().catch(() => null) : null;

  if (!response.ok) {
    const message =
      (payload && typeof payload === 'object' && 'error' in payload && String(payload.error)) ||
      `Anfrage fehlgeschlagen (HTTP ${response.status}).`;
    throw new ApiError(message, response.status);
  }

  return payload as T;
}

const get = <T>(path: string) => apiRequest<T>(path);
const post = <T>(path: string, body?: unknown) =>
  apiRequest<T>(path, { method: 'POST', body: body === undefined ? undefined : JSON.stringify(body) });
const patch = <T>(path: string, body: unknown) =>
  apiRequest<T>(path, { method: 'PATCH', body: JSON.stringify(body) });
const del = <T>(path: string) => apiRequest<T>(path, { method: 'DELETE' });

/** Haengt nur gesetzte Werte als Abfrageparameter an. */
function query(params: Record<string, unknown>): string {
  const search = new URLSearchParams();
  for (const [key, value] of Object.entries(params)) {
    if (value === undefined || value === null || value === '') continue;
    search.set(key, String(value));
  }
  const text = search.toString();
  return text ? `?${text}` : '';
}

export const authApi = {
  login: (identifier: string, password: string) =>
    post<{ token: string; user: AppUser }>('/auth/login', { identifier, password }),
  me: () => get<{ user: AppUser }>('/auth/me'),
  updateMe: (patchBody: Partial<Pick<AppUser, 'color' | 'avatar' | 'theme' | 'theme_mode'>>) =>
    patch<{ user: AppUser }>('/auth/me', patchBody),
  changePassword: (current_password: string, new_password: string) =>
    post<{ ok: true }>('/auth/change-password', { current_password, new_password }),
};

export const usersApi = {
  directory: () => get<{ users: DirectoryUser[] }>('/users/directory'),
  list: () => get<{ users: AppUser[] }>('/users'),
  create: (body: Record<string, unknown>) => post<{ user: AppUser }>('/users', body),
  update: (id: number, body: Record<string, unknown>) => patch<{ user: AppUser }>(`/users/${id}`, body),
  remove: (id: number) => del<{ ok: true }>(`/users/${id}`),
};

export interface CompanyDetail {
  company: Company;
  contacts: Array<Pick<Contact, 'id' | 'first_name' | 'last_name' | 'position' | 'email' | 'phone' | 'avatar' | 'kind' | 'status'>>;
  former: Array<{
    employment_id: number;
    id: number;
    first_name: string | null;
    last_name: string;
    avatar: string | null;
    position: string | null;
    started_on: string | null;
    ended_on: string | null;
    now_company: string | null;
    now_company_id: number | null;
  }>;
  interviews: Interview[];
  history: HistoryEntry[];
  mentioned: HistoryEntry[];
}

export const companiesApi = {
  list: (params: Record<string, unknown> = {}) =>
    get<{ companies: Company[] }>(`/companies${query(params)}`),
  options: () => get<{ industries: string[]; groups: string[] }>('/companies/options'),
  detail: (id: number) => get<CompanyDetail>(`/companies/${id}`),
  create: (body: Record<string, unknown>) => post<{ company: Company }>('/companies', body),
  update: (id: number, body: Record<string, unknown>) =>
    patch<{ company: Company }>(`/companies/${id}`, body),
  remove: (id: number) => del<{ ok: true }>(`/companies/${id}`),
  addInterview: (id: number, body: Record<string, unknown>) =>
    post<{ id: number }>(`/companies/${id}/interviews`, body),
};

export interface ContactDetail {
  contact: Contact;
  employments: Employment[];
  interviews: Interview[];
  history: HistoryEntry[];
  mentioned: HistoryEntry[];
}

export const contactsApi = {
  list: (params: Record<string, unknown> = {}) =>
    get<{ contacts: Contact[] }>(`/contacts${query(params)}`),
  detail: (id: number) => get<ContactDetail>(`/contacts/${id}`),
  create: (body: Record<string, unknown>) => post<{ contact: Contact }>('/contacts', body),
  update: (id: number, body: Record<string, unknown>) =>
    patch<{ contact: Contact }>(`/contacts/${id}`, body),
  remove: (id: number) => del<{ ok: true }>(`/contacts/${id}`),
  addInterview: (id: number, body: Record<string, unknown>) =>
    post<{ id: number }>(`/contacts/${id}/interviews`, body),
  /*
   * Werdegang von Hand pflegen. Die Stationen entstehen zwar beim Setzen eines
   * Arbeitgebers und beim CV-Import von selbst - aber kein Lebenslauf wird
   * vollständig erkannt, und ein falscher Firmenname ließ sich sonst nicht mehr
   * geradeziehen.
   *
   * `company` (Name) oder `company_id` - ein unbekannter Name legt das
   * Unternehmen an, wie im CV-Import auch.
   */
  addEmployment: (id: number, body: Record<string, unknown>) =>
    post<{ id: number }>(`/contacts/${id}/employments`, body),
  updateEmployment: (employmentId: number, body: Record<string, unknown>) =>
    patch<{ ok: true }>(`/contacts/employments/${employmentId}`, body),
  removeEmployment: (employmentId: number) =>
    del<{ ok: true }>(`/contacts/employments/${employmentId}`),
  lastEmployers: () =>
    get<{
      entries: Array<{
        contact_id: number;
        first_name: string | null;
        last_name: string;
        avatar: string | null;
        company_id: number;
        company: string;
        industry: string | null;
        position: string | null;
        ended_on: string | null;
      }>;
    }>('/contacts/last-employers'),
  linkedInPhoto: (url: string) =>
    post<{ avatar: string; bytes: number }>('/contacts/linkedin-photo', { url }),
};

export const tendersApi = {
  list: (params: Record<string, unknown> = {}) => get<{ tenders: Tender[] }>(`/tenders${query(params)}`),
  detail: (id: number) =>
    get<{ tender: Tender; contacts: Contact[]; history: HistoryEntry[] }>(`/tenders/${id}`),
  create: (body: Record<string, unknown>) => post<{ tender: Tender }>('/tenders', body),
  update: (id: number, body: Record<string, unknown>) => patch<{ tender: Tender }>(`/tenders/${id}`, body),
  remove: (id: number) => del<{ ok: true }>(`/tenders/${id}`),
};

export const projectsApi = {
  list: (params: Record<string, unknown> = {}) =>
    get<{ projects: Project[] }>(`/projects${query(params)}`),
  create: (body: Record<string, unknown>) => post<{ project: Project }>('/projects', body),
  update: (id: number, body: Record<string, unknown>) =>
    patch<{ project: Project }>(`/projects/${id}`, body),
  remove: (id: number) => del<{ ok: true }>(`/projects/${id}`),
};

export const leadsApi = {
  list: (archived = false) => get<{ leads: Lead[] }>(`/leads${query({ archived: archived ? 1 : 0 })}`),
  detail: (id: number) =>
    get<{ lead: Lead; todos: LeadTodo[]; history: HistoryEntry[] }>(`/leads/${id}`),
  create: (body: Record<string, unknown>) => post<{ lead: Lead }>('/leads', body),
  update: (id: number, body: Record<string, unknown>) => patch<{ lead: Lead }>(`/leads/${id}`, body),
  remove: (id: number) => del<{ ok: true }>(`/leads/${id}`),
  reminders: () =>
    get<{ due: Lead[]; stale: Lead[]; stale_days: number }>('/leads/reminders'),
  acknowledge: (id: number, snooze_days?: number) =>
    post<{ ok: true }>(`/leads/${id}/acknowledge`, { snooze_days }),
  addTodo: (id: number, text: string, due_on?: string | null) =>
    post<{ id: number }>(`/leads/${id}/todos`, { text, due_on }),
  updateTodo: (todoId: number, body: Record<string, unknown>) =>
    patch<{ ok: true }>(`/leads/todos/${todoId}`, body),
  removeTodo: (todoId: number) => del<{ ok: true }>(`/leads/todos/${todoId}`),
};

/** Vorschlag der KI zu einem Lebenslauf. */
export interface CvSuggestion {
  first_name: string | null;
  last_name: string | null;
  position: string | null;
  email: string | null;
  phone: string | null;
  linkedin: string | null;
  company: string | null;
  tags: string[];
  bio: string | null;
  rate_onsite: number | null;
  rate_remote: number | null;
  employments: Array<{ company: string; position: string | null; from: string | null; to: string | null }>;
  confidence: number | null;
}

export interface CvImport {
  id: number;
  filename: string;
  original_name: string;
  mime: string | null;
  size_bytes: number;
  status: 'eingang' | 'screening' | 'auswahl' | 'verworfen';
  extracted: CvSuggestion | null;
/**
   * Traegt der Lebenslauf ein Bewerbungsfoto? Das Bild selbst steht nicht in
   * der Liste - es wird bei Bedarf einzeln geholt (`cvsApi.photo`) und erst im
   * Browser verkleinert (siehe lib/imageCompress.ts).
   */
  has_photo: boolean;
  error: string | null;
  contact_id: number | null;
  contact_name: string | null;
  uploaded_by_name: string | null;
  created_at: string;
  processed_at: string | null;
}

export const cvsApi = {
  list: () =>
    get<{ imports: CvImport[]; ai: { configured: boolean; model: string } }>('/cvs'),
  /** Mehrere Dateien auf einmal - der Browser setzt die multipart-Grenze selbst. */
  upload: (files: File[]) => {
    const body = new FormData();
    for (const file of files) body.append('files', file);
    return apiRequest<{ ids: number[]; count: number }>('/cvs', { method: 'POST', body });
  },
  analyze: (id: number) =>
    post<{ extracted: CvSuggestion; photo: string | null }>(`/cvs/${id}/analyze`),
  /** Das gefundene Foto, unveraendert - nur fuer das Formular. */
  photo: (id: number) => get<{ photo: string | null }>(`/cvs/${id}/photo`),
  accept: (id: number, overrides: Record<string, unknown> = {}) =>
    post<{ contact_id: number }>(`/cvs/${id}/accept`, overrides),
  reject: (id: number) => post<{ ok: true }>(`/cvs/${id}/reject`),
  remove: (id: number) => del<{ ok: true }>(`/cvs/${id}`),
};

export type AiTask = 'write' | 'improve' | 'shorten' | 'bullets' | 'profile';

/**
 * Zustand der KI-Einrichtung. Der Schlüssel steht hier nur verkürzt
 * ("sk-proj-…a1b2") - vollständig verlässt er den Server nie.
 */
export interface AiConfig {
  configured: boolean;
  model: string;
  defaultModel: string;
  /** 'db' = in den Einstellungen gepflegt, 'env' = aus server/.env, 'none' = keiner */
  source: 'db' | 'env' | 'none';
  masked: string | null;
  envAvailable: boolean;
}

export const aiApi = {
  status: () => get<{ configured: boolean; model: string; tasks: AiTask[] }>('/ai/status'),
  text: (task: AiTask, current: string, prompt?: string) =>
    post<{ text: string; model: string }>('/ai/text', { task, current, prompt }),
  config: () => get<AiConfig>('/ai/config'),
  saveConfig: (changes: { key?: string; model?: string }) => patch<AiConfig>('/ai/config', changes),
  test: () => post<{ ok: true; model: string; ms: number; answer: string }>('/ai/test'),
};

export const perincoApi = {
  status: () => get<{ configured: boolean; url: string | null }>('/perinco/status'),
  contacts: () => get<{ contacts: PerincoContact[]; cached: boolean }>('/perinco/contacts'),
};

export const historyApi = {
  list: (params: Record<string, unknown> = {}) =>
    get<{ entries: HistoryEntry[] }>(`/history${query(params)}`),
  add: (entity_type: string, entity_id: number | null, text: string) =>
    post<{ entry: HistoryEntry }>('/history', { entity_type, entity_id, text }),
  remove: (id: number) => del<{ ok: true }>(`/history/${id}`),
};

export interface SearchGroup {
  type: 'contact' | 'company' | 'tender' | 'project' | 'lead' | 'history';
  label: string;
  items: Array<Record<string, unknown> & { id: number; title?: string }>;
}

export interface MentionCandidate {
  kind: 'user' | 'contact' | 'company';
  id: number;
  label: string;
  hint: string | null;
  avatar: string | null;
  color?: string | null;
}

export interface AiAnswer {
  answer: string;
  refs: Array<{ type: 'contact' | 'company' | 'tender' | 'project' | 'lead'; id: number; label: string }>;
  model: string;
  truncated: boolean;
}

export const searchApi = {
  search: (q: string) => get<{ query: string; groups: SearchGroup[]; total: number }>(`/search${query({ q })}`),
  mentions: (q: string) => get<{ candidates: MentionCandidate[] }>(`/search/mentions${query({ q })}`),
  ask: (question: string) => post<AiAnswer>('/search/ai', { question }),
};

export interface OptionValue {
  id: number;
  field: string;
  value: string;
  position: number;
  /** Wie oft der Wert im Bestand verwendet wird. */
  used: number;
}

export interface OptionField {
  field: string;
  label: string;
  values: OptionValue[];
}

export const optionsApi = {
  list: () => get<{ fields: OptionField[] }>('/options'),
  create: (field: string, value: string) => post<{ id: number }>('/options', { field, value }),
  rename: (id: number, value: string) => patch<{ ok: true; renamed: number }>(`/options/${id}`, { value }),
  remove: (id: number) => del<{ ok: true }>(`/options/${id}`),
};

export interface NetworkData {
  companies: Array<Company & { id: number }>;
  contacts: Array<{
    id: number;
    name: string;
    position: string | null;
    avatar: string | null;
    kind: string;
    status: string;
    company_id: number | null;
  }>;
  edges: Array<Record<string, unknown> & { type: 'employment' | 'former' | 'contact' | 'group' }>;
  groups: Array<{ name: string; count: number }>;
}

export const networkApi = {
  load: (params: Record<string, unknown> = {}) => get<NetworkData>(`/network${query(params)}`),
};

export const connectionsApi = {
  list: () => get<{ connections: Connection[] }>('/connections'),
  create: (contact_a: number, contact_b: number, kind?: string) =>
    post<Connection>('/connections', { contact_a, contact_b, kind }),
  update: (id: number, kind: string) => patch<{ ok: true }>(`/connections/${id}`, { kind }),
  remove: (id: number) => del<{ ok: true }>(`/connections/${id}`),
};

export interface DashboardData {
  counts: Record<string, number>;
  contacts_by_status: Array<{ status: string; count: number }>;
  companies_by_industry: Array<{ industry: string; count: number }>;
  tenders_by_stage: Array<{ stage: string; count: number }>;
  recent: HistoryEntry[];
}

export const dashboardApi = {
  load: () => get<DashboardData>('/dashboard'),
};