import * as plugins from './plugins.js';

export interface IOpenCodeClientOptions {
  baseUrl: string;
  username?: string;
  password?: string;
  fetch?: typeof fetch;
}

export interface IOpenCodeMessagePart {
  type: string;
  [key: string]: unknown;
}

export interface IOpenCodePromptBody {
  messageID?: string;
  model?: {
    providerID: string;
    modelID: string;
  };
  agent?: string;
  noReply?: boolean;
  system?: string;
  tools?: Record<string, boolean>;
  parts: IOpenCodeMessagePart[];
}

export interface IOpenCodeCommandBody {
  messageID?: string;
  agent?: string;
  model?: {
    providerID: string;
    modelID: string;
  };
  command: string;
  arguments?: string;
}

export interface IOpenCodeShellBody {
  agent: string;
  model?: {
    providerID: string;
    modelID: string;
  };
  command: string;
}

export interface IOpenCodeEvent {
  type: string;
  id?: string;
  retry?: number;
  data?: unknown;
  raw: string;
}

export class OpenCodeHttpError extends Error {
  constructor(
    message: string,
    public readonly status: number,
    public readonly body: string,
  ) {
    super(message);
  }
}

export class OpenCodeServerClient {
  private readonly baseUrl: string;
  private readonly fetchImpl: typeof fetch;
  private readonly authorizationHeader?: string;

  constructor(options: IOpenCodeClientOptions) {
    this.baseUrl = options.baseUrl.replace(/\/+$/g, '');
    this.fetchImpl = options.fetch ?? globalThis.fetch.bind(globalThis);
    if (options.username || options.password) {
      const username = options.username ?? 'opencode';
      const password = options.password ?? '';
      this.authorizationHeader = `Basic ${plugins.Buffer.from(`${username}:${password}`).toString('base64')}`;
    }
  }

  async health<T = unknown>() {
    return this.request<T>('/global/health');
  }

  async projects<T = unknown>() {
    return this.request<T>('/project');
  }

  async currentProject<T = unknown>() {
    return this.request<T>('/project/current');
  }

  async path<T = unknown>() {
    return this.request<T>('/path');
  }

  async vcs<T = unknown>() {
    return this.request<T>('/vcs');
  }

  async config<T = unknown>() {
    return this.request<T>('/config');
  }

  async providers<T = unknown>() {
    return this.request<T>('/provider');
  }

  async agents<T = unknown>() {
    return this.request<T>('/agent');
  }

  async commands<T = unknown>() {
    return this.request<T>('/command');
  }

  async sessions<T = unknown>() {
    return this.request<T>('/session');
  }

  async createSession<T = unknown>(body: { parentID?: string; title?: string } = {}) {
    return this.request<T>('/session', { method: 'POST', body });
  }

  async session<T = unknown>(id: string) {
    return this.request<T>(`/session/${encodeURIComponent(id)}`);
  }

  async updateSession<T = unknown>(id: string, body: { title?: string }) {
    return this.request<T>(`/session/${encodeURIComponent(id)}`, { method: 'PATCH', body });
  }

  async deleteSession<T = unknown>(id: string) {
    return this.request<T>(`/session/${encodeURIComponent(id)}`, { method: 'DELETE' });
  }

  async sessionStatus<T = unknown>() {
    return this.request<T>('/session/status');
  }

  async children<T = unknown>(id: string) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/children`);
  }

  async todo<T = unknown>(id: string) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/todo`);
  }

  async messages<T = unknown>(id: string, limit?: number) {
    const query = limit ? `?limit=${encodeURIComponent(`${limit}`)}` : '';
    return this.request<T>(`/session/${encodeURIComponent(id)}/message${query}`);
  }

  async message<T = unknown>(id: string, messageID: string) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/message/${encodeURIComponent(messageID)}`);
  }

  async prompt<T = unknown>(id: string, body: IOpenCodePromptBody) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/message`, { method: 'POST', body });
  }

  async promptAsync(id: string, body: IOpenCodePromptBody) {
    return this.request<void>(`/session/${encodeURIComponent(id)}/prompt_async`, { method: 'POST', body });
  }

  async command<T = unknown>(id: string, body: IOpenCodeCommandBody) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/command`, { method: 'POST', body });
  }

  async shell<T = unknown>(id: string, body: IOpenCodeShellBody) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/shell`, { method: 'POST', body });
  }

  async abort<T = unknown>(id: string) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/abort`, { method: 'POST' });
  }

  async diff<T = unknown>(id: string, messageID?: string) {
    const query = messageID ? `?messageID=${encodeURIComponent(messageID)}` : '';
    return this.request<T>(`/session/${encodeURIComponent(id)}/diff${query}`);
  }

  async revert<T = unknown>(id: string, body: { messageID: string; partID?: string }) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/revert`, { method: 'POST', body });
  }

  async unrevert<T = unknown>(id: string) {
    return this.request<T>(`/session/${encodeURIComponent(id)}/unrevert`, { method: 'POST' });
  }

  async respondToPermission<T = unknown>(
    sessionID: string,
    permissionID: string,
    body: { response: string; remember?: boolean },
  ) {
    return this.request<T>(
      `/session/${encodeURIComponent(sessionID)}/permissions/${encodeURIComponent(permissionID)}`,
      { method: 'POST', body },
    );
  }

  async findFiles<T = unknown>(query: { query: string; type?: 'file' | 'directory'; directory?: string; limit?: number }) {
    return this.request<T>(`/find/file?${new URLSearchParams(stringifyQuery(query))}`);
  }

  async findText<T = unknown>(query: { pattern: string }) {
    return this.request<T>(`/find?${new URLSearchParams(stringifyQuery(query))}`);
  }

  async fileContent<T = unknown>(path: string) {
    return this.request<T>(`/file/content?${new URLSearchParams({ path })}`);
  }

  async fileStatus<T = unknown>() {
    return this.request<T>('/file/status');
  }

  async *events(signal?: AbortSignal): AsyncGenerator<IOpenCodeEvent> {
    const response = await this.fetchImpl(`${this.baseUrl}/event`, {
      headers: this.createHeaders(),
      signal,
    });
    if (!response.ok) {
      throw await this.createHttpError(response, '/event');
    }
    if (!response.body) {
      return;
    }

    const reader = response.body.getReader();
    const decoder = new TextDecoder();
    let buffer = '';
    while (true) {
      const { value, done } = await reader.read();
      if (done) {
        break;
      }
      buffer += decoder.decode(value, { stream: true });
      const parts = buffer.split(/\n\n/);
      buffer = parts.pop() ?? '';
      for (const part of parts) {
        const event = parseServerSentEvent(part);
        if (event) {
          yield event;
        }
      }
    }
    const finalEvent = parseServerSentEvent(buffer);
    if (finalEvent) {
      yield finalEvent;
    }
  }

  private async request<T>(path: string, options: { method?: string; body?: unknown } = {}) {
    const response = await this.fetchImpl(`${this.baseUrl}${path}`, {
      method: options.method ?? 'GET',
      headers: this.createHeaders(options.body !== undefined),
      body: options.body === undefined ? undefined : JSON.stringify(options.body),
    });
    if (!response.ok) {
      throw await this.createHttpError(response, path);
    }
    if (response.status === 204) {
      return undefined as T;
    }
    const text = await response.text();
    if (!text) {
      return undefined as T;
    }
    return JSON.parse(text) as T;
  }

  private createHeaders(hasJsonBody = false) {
    const headers: Record<string, string> = {};
    if (hasJsonBody) {
      headers['content-type'] = 'application/json';
    }
    if (this.authorizationHeader) {
      headers.authorization = this.authorizationHeader;
    }
    return headers;
  }

  private async createHttpError(response: Response, path: string) {
    const body = await response.text();
    return new OpenCodeHttpError(`OpenCode request failed: ${response.status} ${path}`, response.status, body);
  }
}

export const parseServerSentEvent = (raw: string): IOpenCodeEvent | undefined => {
  const trimmed = raw.trim();
  if (!trimmed) {
    return undefined;
  }

  const dataLines: string[] = [];
  let type = 'message';
  let id: string | undefined;
  let retry: number | undefined;

  for (const line of trimmed.split(/\r?\n/)) {
    if (line.startsWith(':')) {
      continue;
    }
    const separator = line.indexOf(':');
    const field = separator === -1 ? line : line.slice(0, separator);
    const value = separator === -1 ? '' : line.slice(separator + 1).replace(/^ /, '');
    if (field === 'event') {
      type = value;
    } else if (field === 'data') {
      dataLines.push(value);
    } else if (field === 'id') {
      id = value;
    } else if (field === 'retry') {
      const retryNumber = Number(value);
      if (Number.isFinite(retryNumber)) {
        retry = retryNumber;
      }
    }
  }

  const dataText = dataLines.join('\n');
  const data = parseJsonIfPossible(dataText);
  if (type === 'message' && data && typeof data === 'object' && 'type' in data) {
    type = String((data as { type: unknown }).type);
  }
  return { type, id, retry, data, raw };
};

const parseJsonIfPossible = (value: string) => {
  if (!value) {
    return undefined;
  }
  try {
    return JSON.parse(value) as unknown;
  } catch {
    return value;
  }
};

const stringifyQuery = (query: Record<string, string | number | boolean | undefined>) => {
  const result: Record<string, string> = {};
  for (const [key, value] of Object.entries(query)) {
    if (value !== undefined) {
      result[key] = String(value);
    }
  }
  return result;
};