import { existsSync, readdirSync } from "node:fs"
import { join } from "node:path"
import { MESSAGE_STORAGE } from "../../features/hook-message-injector"
import type { DelegateTaskArgs } from "./types"

/**
 * Parse a model string in "provider/model" format.
 */
export function parseModelString(model: string): { providerID: string; modelID: string } | undefined {
  const parts = model.split("/")
  if (parts.length >= 2) {
    return { providerID: parts[0], modelID: parts.slice(1).join("/") }
  }
  return undefined
}

/**
 * Get the message directory for a session, checking both direct and nested paths.
 */
export function getMessageDir(sessionID: string): string | null {
  if (!sessionID.startsWith("ses_")) return null
  if (!existsSync(MESSAGE_STORAGE)) return null

  const directPath = join(MESSAGE_STORAGE, sessionID)
  if (existsSync(directPath)) return directPath

  for (const dir of readdirSync(MESSAGE_STORAGE)) {
    const sessionPath = join(MESSAGE_STORAGE, dir, sessionID)
    if (existsSync(sessionPath)) return sessionPath
  }

  return null
}

/**
 * Format a duration between two dates as a human-readable string.
 */
export function formatDuration(start: Date, end?: Date): string {
  const duration = (end ?? new Date()).getTime() - start.getTime()
  const seconds = Math.floor(duration / 1000)
  const minutes = Math.floor(seconds / 60)
  const hours = Math.floor(minutes / 60)

  if (hours > 0) return `${hours}h ${minutes % 60}m ${seconds % 60}s`
  if (minutes > 0) return `${minutes}m ${seconds % 60}s`
  return `${seconds}s`
}

/**
 * Context for error formatting.
 */
export interface ErrorContext {
  operation: string
  args?: DelegateTaskArgs
  sessionID?: string
  agent?: string
  category?: string
}

/**
 * Format an error with detailed context for debugging.
 */
export function formatDetailedError(error: unknown, ctx: ErrorContext): string {
  const message = error instanceof Error ? error.message : String(error)
  const stack = error instanceof Error ? error.stack : undefined

  const lines: string[] = [
    `${ctx.operation} failed`,
    "",
    `**Error**: ${message}`,
  ]

  if (ctx.sessionID) {
    lines.push(`**Session ID**: ${ctx.sessionID}`)
  }

  if (ctx.agent) {
    lines.push(`**Agent**: ${ctx.agent}${ctx.category ? ` (category: ${ctx.category})` : ""}`)
  }

  if (ctx.args) {
    lines.push("", "**Arguments**:")
    lines.push(`- description: "${ctx.args.description}"`)
    lines.push(`- category: ${ctx.args.category ?? "(none)"}`)
    lines.push(`- subagent_type: ${ctx.args.subagent_type ?? "(none)"}`)
    lines.push(`- run_in_background: ${ctx.args.run_in_background}`)
    lines.push(`- load_skills: [${ctx.args.load_skills?.join(", ") ?? ""}]`)
    if (ctx.args.session_id) {
      lines.push(`- session_id: ${ctx.args.session_id}`)
    }
  }

  if (stack) {
    lines.push("", "**Stack Trace**:")
    lines.push("```")
    lines.push(stack.split("\n").slice(0, 10).join("\n"))
    lines.push("```")
  }

  return lines.join("\n")
}