// Pure utility functions for the team orchestrator
// Extracted from team-orchestrator.js for testability

import { mkdir, readFile, rename, rm, writeFile } from "node:fs/promises"
import path from "node:path"

export const REGISTRY_VERSION = 1
export const LOCK_TIMEOUT_MS = 5000
export const LOCK_RETRY_MS = 50
export const LOCK_STALE_MS = 30 * 1000

export function now() {
  return new Date().toISOString()
}

export function createTaskID() {
  const random = Math.random().toString(36).slice(2, 8)
  return `team_${Date.now().toString(36)}_${random}`
}

export function stateRoot(worktree) {
  return path.join(worktree, ".opencode", "state")
}

export function artifactRoot(worktree) {
  return path.join(stateRoot(worktree), "artifacts")
}

export function registryFile(worktree) {
  return path.join(stateRoot(worktree), "tasks.json")
}

export function lockDirectory(worktree) {
  return path.join(stateRoot(worktree), "tasks.lock")
}

export function temporaryRegistryFile(worktree) {
  return path.join(stateRoot(worktree), `tasks.${process.pid}.tmp`)
}

export function projectRootFromContext(context) {
  if (context.worktree && context.worktree !== "/") {
    return context.worktree
  }
  return context.directory
}

export function isErrno(error, code) {
  return Boolean(error && typeof error === "object" && "code" in error && error.code === code)
}

export function errorMessage(error) {
  if (error instanceof Error) return error.message
  return String(error)
}

export function isPidAlive(pid) {
  try {
    process.kill(pid, 0)
    return true
  } catch (error) {
    return false
  }
}

export async function sleep(ms) {
  await new Promise(resolve => setTimeout(resolve, ms))
}

function lockMetaFile(worktree) {
  return path.join(lockDirectory(worktree), "meta.json")
}

export async function acquireLock(worktree) {
  await ensureState(worktree)
  const deadline = Date.now() + LOCK_TIMEOUT_MS
  const lockPath = lockDirectory(worktree)

  while (Date.now() < deadline) {
    try {
      await mkdir(lockPath)
      const meta = { owner: process.pid, createdAt: Date.now() }
      await writeFile(lockMetaFile(worktree), JSON.stringify(meta), "utf8")
      return
    } catch (error) {
      if (!isErrno(error, "EEXIST")) throw error
      await recoverStaleLock(worktree)
      await sleep(LOCK_RETRY_MS)
    }
  }

  throw new Error("Timed out acquiring the team task registry lock")
}

export async function recoverStaleLock(worktree) {
  const lockPath = lockDirectory(worktree)
  const metaPath = lockMetaFile(worktree)

  try {
    const raw = await readFile(metaPath, "utf8")
    const meta = JSON.parse(raw)
    if (typeof meta.createdAt === "number" && Date.now() - meta.createdAt < LOCK_STALE_MS) {
      if (typeof meta.owner === "number" && isPidAlive(meta.owner)) {
        return
      }
    }
  } catch (error) {
    if (isErrno(error, "ENOENT")) {
      // meta file missing — safe to reclaim
    } else {
      return // corrupt meta — don't reclaim
    }
  }

  try {
    await rm(lockPath, { recursive: true, force: true })
  } catch (error) {
    if (!isErrno(error, "ENOENT")) {
      throw error
    }
  }
}

export async function withLockedRegistry(worktree, mutate) {
  await acquireLock(worktree)
  try {
    const registry = await loadRegistry(worktree)
    const result = await mutate(registry)
    await saveRegistry(worktree, registry)
    return result
  } finally {
    await rm(lockDirectory(worktree), { recursive: true, force: true })
  }
}

export async function ensureState(worktree) {
  await mkdir(artifactRoot(worktree), { recursive: true })
}

export async function loadRegistry(worktree) {
  await ensureState(worktree)
  const file = registryFile(worktree)
  try {
    const raw = await readFile(file, "utf8")
    const parsed = JSON.parse(raw)
    if (!Array.isArray(parsed.tasks)) {
      return { version: REGISTRY_VERSION, tasks: [] }
    }
    return parsed
  } catch (error) {
    if (error && typeof error === "object" && "code" in error && error.code === "ENOENT") {
      return { version: REGISTRY_VERSION, tasks: [] }
    }
    throw error
  }
}

export async function saveRegistry(worktree, registry) {
  await ensureState(worktree)
  const file = registryFile(worktree)
  const temporaryFile = temporaryRegistryFile(worktree)
  await writeFile(
    temporaryFile,
    `${JSON.stringify({ version: REGISTRY_VERSION, tasks: registry.tasks }, null, 2)}\n`,
    "utf8",
  )
  await rename(temporaryFile, file)
}

export function upsertTask(registry, task) {
  const index = registry.tasks.findIndex(existing => existing.id === task.id)
  if (index === -1) {
    registry.tasks.push(task)
    return
  }
  registry.tasks[index] = task
}

export function getTask(registry, taskID) {
  return registry.tasks.find(task => task.id === taskID)
}

export async function addTask(worktree, task) {
  await withLockedRegistry(worktree, registry => {
    upsertTask(registry, task)
  })
}

export async function readTask(worktree, taskID) {
  const registry = await loadRegistry(worktree)
  return getTask(registry, taskID)
}

export async function updateTask(worktree, taskID, mutate) {
  return withLockedRegistry(worktree, registry => {
    const task = getTask(registry, taskID)
    if (!task) {
      throw new Error(`Unknown task_id: ${taskID}`)
    }
    return mutate(task, registry)
  })
}

export function buildWorkerPrompt(input) {
  const sections = [
    "You are a delegated worker in a multi-agent team orchestration prototype.",
    "Stay focused on the assigned scope and produce a concise final result that a coordinator can synthesize.",
    "",
    `## Task ID\n${input.taskID}`,
    "",
    `## Title\n${input.title}`,
  ]

  if (input.goal) {
    sections.push("", `## Goal\n${input.goal}`)
  }

  if (input.files.length > 0) {
    sections.push("", `## Suggested Files\n${input.files.map(file => `- ${file}`).join("\n")}`)
  }

  sections.push(
    "",
    "## Instructions",
    input.prompt,
    "",
    "## Response Contract",
    "Return a final response with these sections:",
    "## Summary",
    "## Files",
    "- file paths you changed or inspected",
    "## Risks",
    "- remaining risks or unknowns",
    "## Next Steps",
    "- any follow-up the coordinator should consider",
  )

  return sections.join("\n")
}

export function extractTextFromParts(parts) {
  return parts
    .filter(part => part.type === "text" && typeof part.text === "string")
    .map(part => part.text.trim())
    .filter(Boolean)
    .join("\n\n")
}

export const STATUS_ICONS = {
  running: "▸",
  ready: "◦",
  done: "✓",
  cancelled: "○",
  error: "✗",
}

export function formatTaskLine(task, liveStatus) {
  const status = liveStatus || task.status
  const icon = STATUS_ICONS[status] || "•"
  return `${icon} ${task.id}  ${status}  ${task.agent}  ${task.title}`
}

export function artifactPathForDisplay(worktree, artifactPath) {
  if (!artifactPath) return ""
  return path.relative(worktree, artifactPath) || artifactPath
}

export async function recordTaskError(worktree, taskID, error) {
  return updateTask(worktree, taskID, task => {
    if (task.status === "cancelled") {
      return { ...task }
    }
    task.status = "error"
    task.updatedAt = now()
    task.error = errorMessage(error)
    return { ...task }
  })
}

export async function recordTaskCompletion(worktree, taskID, latest, artifactPath) {
  return updateTask(worktree, taskID, task => {
    if (task.status === "cancelled") {
      return {
        cancelled: true,
        task: { ...task },
      }
    }

    task.status = "done"
    task.updatedAt = now()
    task.summary = latest.text || undefined
    task.artifactPath = artifactPath
    task.lastMessageID = latest.messageID
    delete task.error

    return {
      cancelled: false,
      task: { ...task },
    }
  })
}