import { randomBytes } from 'crypto'
import type { AppState } from './state/AppState.js'
import type { AgentId } from './types/ids.js'
import { getTaskOutputPath } from './utils/task/diskOutput.js'

export type TaskType =
 | 'local_bash'
 | 'local_agent'
 | 'remote_agent'
 | 'in_process_teammate'
 | 'local_workflow'
 | 'monitor_mcp'
 | 'dream'

export type TaskStatus =
 | 'pending'
 | 'running'
 | 'completed'
 | 'failed'
 | 'killed'

/**
 * True when a task is in a terminal state and will not transition further.
 * Used to guard against injecting messages into dead teammates, evicting
 * finished tasks from AppState, and orphan-cleanup paths.
 */
export function isTerminalTaskStatus(status: TaskStatus): boolean {
 return status === 'completed' || status === 'failed' || status === 'killed'
}

export type TaskHandle = {
 taskId: string
 cleanup?: () => void
}

export type SetAppState = (f: (prev: AppState) => AppState) => void

export type TaskContext = {
 abortController: AbortController
 getAppState: () => AppState
 setAppState: SetAppState
}

// Base fields shared by all task states
export type TaskStateBase = {
 id: string
 type: TaskType
 status: TaskStatus
 description: string
 toolUseId?: string
 startTime: number
 endTime?: number
 totalPausedMs?: number
 outputFile: string
 outputOffset: number
 notified: boolean
}

export type LocalShellSpawnInput = {
 command: string
 description: string
 timeout?: number
 toolUseId?: string
 agentId?: AgentId
 /** UI display variant: description-as-label, dialog title, status bar pill. */
 kind?: 'bash' | 'monitor'
}

// What getTaskByType dispatches for: kill. spawn/render were never
// called polymorphically (removed in #22546). All six kill implementations
// use only setAppState — getAppState/abortController were dead weight.
export type Task = {
 name: string
 type: TaskType
 kill(taskId: string, setAppState: SetAppState): Promise<void>
}

// Task ID prefixes
const TASK_ID_PREFIXES: Record<string, string> = {
 local_bash: 'b', // Keep as 'b' for backward compatibility
 local_agent: 'a',
 remote_agent: 'r',
 in_process_teammate: 't',
 local_workflow: 'w',
 monitor_mcp: 'm',
 dream: 'd',
}

// Get task ID prefix
function getTaskIdPrefix(type: TaskType): string {
 return TASK_ID_PREFIXES[type] ?? 'x'
}

// Case-insensitive-safe alphabet (digits + lowercase) for task IDs.
// 36^8 ≈ 2.8 trillion combinations, sufficient to resist brute-force symlink attacks.
const TASK_ID_ALPHABET = '0123456789abcdefghijklmnopqrstuvwxyz'

export function generateTaskId(type: TaskType): string {
 const prefix = getTaskIdPrefix(type)
 const bytes = randomBytes(8)
 let id = prefix
 for (let i = 0; i < 8; i++) {
 id += TASK_ID_ALPHABET[bytes[i]! % TASK_ID_ALPHABET.length]
 }
 return id
}

export function createTaskStateBase(
 id: string,
 type: TaskType,
 description: string,
 toolUseId?: string,
): TaskStateBase {
 return {
 id,
 type,
 status: 'pending',
 description,
 toolUseId,
 startTime: Date.now(),
 outputFile: getTaskOutputPath(id),
 outputOffset: 0,
 notified: false,
 }
}