/**
 * March Agent SDK - Attachment Client
 * Port of Python march_agent/attachment_client.py
 */

import { APIException } from './exceptions.js'
import { AttachmentInfoSchema, type AttachmentInfo } from './types.js'

/**
 * Re-export AttachmentInfo for convenience
 */
export { type AttachmentInfo } from './types.js'

/**
 * Create AttachmentInfo from API data
 */
export function createAttachmentInfo(data: Record<string, unknown>): AttachmentInfo {
    return AttachmentInfoSchema.parse({
        url: data.url,
        filename: data.filename || data.file_name,
        contentType: data.content_type || data.contentType,
        size: data.size,
        fileType: data.file_type || data.fileType,
    })
}

/**
 * HTTP client for downloading attachments.
 */
export class AttachmentClient {
    private readonly baseUrl: string

    constructor(baseUrl: string) {
        this.baseUrl = baseUrl.replace(/\/$/, '')
    }

    /**
     * Build full URL for an attachment.
     */
    private buildUrl(attachmentUrl: string): string {
        // If already absolute URL, use as-is
        if (attachmentUrl.startsWith('http://') || attachmentUrl.startsWith('https://')) {
            return attachmentUrl
        }
        // Otherwise, prepend base URL
        return `${this.baseUrl}${attachmentUrl.startsWith('/') ? '' : '/'}${attachmentUrl}`
    }

    /**
     * Download attachment as bytes (Buffer).
     */
    async download(url: string): Promise<Buffer> {
        const fullUrl = this.buildUrl(url)

        try {
            const response = await fetch(fullUrl)

            if (!response.ok) {
                throw new APIException(`Failed to download attachment: ${response.status}`, response.status)
            }

            const arrayBuffer = await response.arrayBuffer()
            return Buffer.from(arrayBuffer)
        } catch (error) {
            if (error instanceof APIException) throw error
            throw new APIException(`Failed to download attachment: ${error}`)
        }
    }

    /**
     * Download attachment as base64 string.
     * Useful for LLM vision APIs.
     */
    async downloadAsBase64(url: string): Promise<string> {
        const buffer = await this.download(url)
        return buffer.toString('base64')
    }
}