const CARBONE_VERSION = "5";

export type CarboneSuccess<T> = {
  success: true;
  data: T;
  hasMore?: boolean;
  nextCursor?: string;
};

export type CarboneError = {
  success: false;
  error: string;
};

export type CarboneResponse<T> = CarboneSuccess<T> | CarboneError;

export type CarboneDownloadResult = {
  buffer: Uint8Array;
  contentType: string | null;
  contentDisposition: string | null;
};

export class CarboneClient {
  constructor(
    private baseUrl: string,
    private apiToken: string,
  ) {}

  private buildHeaders(extra?: Record<string, string>) {
    return {
      Authorization: `Bearer ${this.apiToken}`,
      "carbone-version": CARBONE_VERSION,
      ...extra,
    };
  }

  private async parseResponse<T>(res: Response): Promise<T> {
    const contentType = res.headers.get("content-type") || "";

    if (!res.ok) {
      let message = `Carbone request failed: ${res.status}`;
      try {
        const err = await res.json();
        message = err?.error || err?.message || message;
      } catch {
        // ignore json parse errors
      }
      throw new Error(message);
    }

    if (contentType.includes("application/json")) {
      return res.json() as Promise<T>;
    }

    return res as unknown as T;
  }

  private toQuery(params?: Record<string, unknown>) {
    const qs = new URLSearchParams();
    if (!params) return "";
    for (const [key, value] of Object.entries(params)) {
      if (value === undefined || value === null) continue;
      qs.set(key, String(value));
    }
    const s = qs.toString();
    return s ? `?${s}` : "";
  }

  async listTemplates(params?: {
    id?: string;
    versionId?: string;
    category?: string;
    origin?: 0 | 1;
    includeVersions?: boolean;
    search?: string;
    limit?: number;
    cursor?: string;
  }) {
    const res = await fetch(
      `${this.baseUrl}/templates${this.toQuery(params)}`,
      {
        method: "GET",
        headers: this.buildHeaders(),
      },
    );
    return this.parseResponse<
      CarboneResponse<
        Array<{
          id: string;
          versionId: string;
          deployedAt: number;
          createdAt: number;
          expireAt?: number;
          size: number;
          type: string;
          name?: string;
          category?: string;
          comment?: string;
          tags?: string[];
          origin?: number;
        }>
      >
    >(res);
  }

  async listCategories() {
    const res = await fetch(`${this.baseUrl}/templates/categories`, {
      method: "GET",
      headers: this.buildHeaders(),
    });
    return this.parseResponse<CarboneResponse<Array<{ name: string }>>>(res);
  }

  async listTags() {
    const res = await fetch(`${this.baseUrl}/templates/tags`, {
      method: "GET",
      headers: this.buildHeaders(),
    });
    return this.parseResponse<CarboneResponse<Array<{ name: string }>>>(res);
  }

  async uploadTemplateJson(body: {
    template: string;
    versioning?: boolean;
    id?: string;
    name?: string;
    comment?: string;
    tags?: string[];
    category?: string;
    sample?: unknown[];
    deployedAt?: number;
    expireAt?: number;
  }) {
    const res = await fetch(`${this.baseUrl}/template`, {
      method: "POST",
      headers: this.buildHeaders({
        "Content-Type": "application/json",
      }),
      body: JSON.stringify(body),
    });
    return this.parseResponse<
      CarboneResponse<{
        id?: string;
        versionId?: string;
        templateId?: string;
        type?: string;
        size?: number;
        createdAt?: number;
      }>
    >(res);
  }

  async uploadTemplateFile(input: {
    file: Blob;
    filename: string;
    versioning?: boolean;
    id?: string;
    name?: string;
    comment?: string;
    tags?: string[];
    category?: string;
    sample?: unknown[];
    deployedAt?: number;
    expireAt?: number;
  }) {
    const form = new FormData();

    if (input.versioning !== undefined) {
      form.append("versioning", String(input.versioning));
    }
    if (input.id) form.append("id", input.id);
    if (input.name) form.append("name", input.name);
    if (input.comment) form.append("comment", input.comment);
    if (input.category) form.append("category", input.category);
    if (input.tags) {
      for (const tag of input.tags) form.append("tags[]", tag);
    }
    if (input.sample) form.append("sample", JSON.stringify(input.sample));
    if (input.deployedAt !== undefined) {
      form.append("deployedAt", String(input.deployedAt));
    }
    if (input.expireAt !== undefined) {
      form.append("expireAt", String(input.expireAt));
    }

    // template should be appended last
    form.append("template", input.file, input.filename);

    const res = await fetch(`${this.baseUrl}/template`, {
      method: "POST",
      headers: this.buildHeaders(),
      body: form,
    });
    return this.parseResponse<
      CarboneResponse<{
        id?: string;
        versionId?: string;
        templateId?: string;
        type?: string;
        size?: number;
        createdAt?: number;
      }>
    >(res);
  }

  async patchTemplate(
    id: string,
    body: {
      name?: string;
      comment?: string;
      tags?: string[];
      category?: string;
      deployedAt?: number;
      expireAt?: number;
    },
  ) {
    const res = await fetch(`${this.baseUrl}/template/${id}`, {
      method: "PATCH",
      headers: this.buildHeaders({
        "Content-Type": "application/json",
      }),
      body: JSON.stringify(body),
    });
    return this.parseResponse<CarboneResponse<true>>(res);
  }

  async deleteTemplate(id: string) {
    const res = await fetch(`${this.baseUrl}/template/${id}`, {
      method: "DELETE",
      headers: this.buildHeaders(),
    });
    return this.parseResponse<CarboneResponse<true>>(res);
  }

  async downloadTemplate(id: string): Promise<CarboneDownloadResult> {
    const res = await fetch(`${this.baseUrl}/template/${id}`, {
      method: "GET",
      headers: this.buildHeaders(),
    });

    if (!res.ok) {
      const err = await res.json().catch(() => null);
      throw new Error(
        err?.error || `Failed to download template: ${res.status}`,
      );
    }

    return {
      buffer: new Uint8Array(await res.arrayBuffer()),
      contentType: res.headers.get("content-type"),
      contentDisposition: res.headers.get("content-disposition"),
    };
  }

  async render(
    templateIdOrVersionId: string,
    body: Record<string, unknown>,
    opts?: { download?: boolean },
  ) {
    const query = opts?.download ? "?download=true" : "";
    const res = await fetch(
      `${this.baseUrl}/render/${templateIdOrVersionId}${query}`,
      {
        method: "POST",
        headers: this.buildHeaders({
          "Content-Type": "application/json",
        }),
        body: JSON.stringify(body),
      },
    );

    if (opts?.download) {
      if (!res.ok) {
        const err = await res.json().catch(() => null);
        throw new Error(err?.error || `Render failed: ${res.status}`);
      }
      return {
        buffer: new Uint8Array(await res.arrayBuffer()),
        contentType: res.headers.get("content-type"),
        contentDisposition: res.headers.get("content-disposition"),
      } satisfies CarboneDownloadResult;
    }

    return this.parseResponse<CarboneResponse<{ renderId: string }>>(res);
  }

  async renderFromTemplate(
    body: Record<string, unknown>,
    opts?: { download?: boolean },
  ) {
    const query = opts?.download ? "?download=true" : "";
    const res = await fetch(`${this.baseUrl}/render/template${query}`, {
      method: "POST",
      headers: this.buildHeaders({
        "Content-Type": "application/json",
      }),
      body: JSON.stringify(body),
    });

    if (opts?.download) {
      if (!res.ok) {
        const err = await res.json().catch(() => null);
        throw new Error(err?.error || `Render failed: ${res.status}`);
      }
      return {
        buffer: new Uint8Array(await res.arrayBuffer()),
        contentType: res.headers.get("content-type"),
        contentDisposition: res.headers.get("content-disposition"),
      } satisfies CarboneDownloadResult;
    }

    return this.parseResponse<CarboneResponse<{ renderId: string }>>(res);
  }

  async downloadRender(renderId: string): Promise<CarboneDownloadResult> {
    const res = await fetch(`${this.baseUrl}/render/${renderId}`, {
      method: "GET",
    });

    if (!res.ok) {
      const err = await res.json().catch(() => null);
      throw new Error(err?.error || `Failed to download render: ${res.status}`);
    }

    return {
      buffer: new Uint8Array(await res.arrayBuffer()),
      contentType: res.headers.get("content-type"),
      contentDisposition: res.headers.get("content-disposition"),
    };
  }
}