/**
 * March Agent SDK - Agent State Client
 * Port of Python march_agent/agent_state_client.py
 */

import { APIException } from './exceptions.js'

export interface AgentStateResponse {
    conversationId: string
    namespace: string
    state: Record<string, unknown>
    createdAt?: string
    updatedAt?: string
}

/**
 * Async HTTP client for agent-state API.
 * Used for storing framework-specific state (e.g., Pydantic AI messages).
 */
export class AgentStateClient {
    private readonly baseUrl: string

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

    /**
     * Store or update agent state.
     */
    async put(
        conversationId: string,
        namespace: string,
        state: Record<string, unknown>
    ): Promise<{ conversationId: string; namespace: string; created: boolean }> {
        const url = `${this.baseUrl}/agent-state/${conversationId}`
        const payload = {
            namespace,
            state,
        }

        try {
            const response = await fetch(url, {
                method: 'PUT',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify(payload),
            })

            if (!response.ok) {
                const errorText = await response.text()
                throw new APIException(`Failed to store agent state: ${response.status} - ${errorText}`, response.status)
            }

            return await response.json() as { conversationId: string; namespace: string; created: boolean }
        } catch (error) {
            if (error instanceof APIException) throw error
            throw new APIException(`Failed to store agent state: ${error}`)
        }
    }

    /**
     * Get agent state.
     */
    async get(
        conversationId: string,
        namespace: string
    ): Promise<AgentStateResponse | null> {
        const url = new URL(`${this.baseUrl}/agent-state/${conversationId}`)
        url.searchParams.set('namespace', namespace)

        try {
            const response = await fetch(url.toString())

            if (response.status === 404) {
                return null
            }

            if (!response.ok) {
                const errorText = await response.text()
                throw new APIException(`Failed to get agent state: ${response.status} - ${errorText}`, response.status)
            }

            return await response.json() as AgentStateResponse
        } catch (error) {
            if (error instanceof APIException) throw error
            throw new APIException(`Failed to get agent state: ${error}`)
        }
    }

    /**
     * Delete agent state.
     */
    async delete(
        conversationId: string,
        namespace?: string
    ): Promise<{ conversationId: string; namespace?: string; deleted: number }> {
        const url = new URL(`${this.baseUrl}/agent-state/${conversationId}`)
        if (namespace) {
            url.searchParams.set('namespace', namespace)
        }

        try {
            const response = await fetch(url.toString(), { method: 'DELETE' })

            if (!response.ok) {
                const errorText = await response.text()
                throw new APIException(`Failed to delete agent state: ${response.status} - ${errorText}`, response.status)
            }

            return await response.json() as { conversationId: string; namespace?: string; deleted: number }
        } catch (error) {
            if (error instanceof APIException) throw error
            throw new APIException(`Failed to delete agent state: ${error}`)
        }
    }
}