import type { GatewayEventPayload } from '@/lib/chat-messages'
import { normalizePersonalityValue } from '@/lib/chat-runtime'

import type { ClientSessionState } from '../../../types'

type SessionRuntimeStatePatch = Partial<
  Pick<
    ClientSessionState,
    'branch' | 'cwd' | 'fast' | 'model' | 'personality' | 'provider' | 'reasoningEffort' | 'serviceTier' | 'yolo'
  >
>

export function sessionInfoStatePatch(payload: GatewayEventPayload | undefined): SessionRuntimeStatePatch {
  const patch: SessionRuntimeStatePatch = {}

  if (typeof payload?.model === 'string') {
    patch.model = payload.model || ''
  }

  if (typeof payload?.provider === 'string') {
    patch.provider = payload.provider || ''
  }

  if (typeof payload?.cwd === 'string') {
    patch.cwd = payload.cwd
  }

  if (typeof payload?.branch === 'string') {
    patch.branch = payload.branch
  }

  if (typeof payload?.personality === 'string') {
    patch.personality = normalizePersonalityValue(payload.personality)
  }

  if (typeof payload?.reasoning_effort === 'string') {
    patch.reasoningEffort = payload.reasoning_effort
  }

  if (typeof payload?.service_tier === 'string') {
    patch.serviceTier = payload.service_tier
  }

  if (typeof payload?.fast === 'boolean') {
    patch.fast = payload.fast
  }

  if (typeof payload?.yolo === 'boolean') {
    patch.yolo = payload.yolo
  }

  return patch
}

export function hasSessionInfoStatePatch(patch: SessionRuntimeStatePatch): boolean {
  return Object.keys(patch).length > 0
}

// Minimum gap between two assistant-text flushes during a stream. Was 16ms
// (rAF only), which at typical LLM token rates of ~30-80 tok/sec meant every
// token got its own React commit + Streamdown markdown re-parse, scaling
// linearly with the growing last-block length. Bumping to 33ms lets ~2 tokens
// batch into one commit at 60 tok/sec without introducing visible lag on the
// streaming text (still 30 fps of visible text growth). Big perceived
// smoothness win on long messages with big trailing paragraphs; see
// `scripts/profile-typing-lag.md` for the measurement work behind this.
export const STREAM_DELTA_FLUSH_MS = 33

// Gateway/provider failures sometimes arrive as message.complete text instead
// of an explicit error event. Treat matches as inline assistant errors so they
// persist like real error events and don't get erased by hydrate fallback.
const COMPLETION_ERROR_PATTERNS = [
  /^API call failed after \d+ retries:/i,
  /^HTTP\s+\d{3}\b/i,
  /^(Provider|Gateway)\s+error:/i
]

export function completionErrorText(finalText: string): string | null {
  const text = finalText.trim()

  return text && COMPLETION_ERROR_PATTERNS.some(re => re.test(text)) ? text : null
}

export const SUBAGENT_EVENT_TYPES = new Set([
  'subagent.spawn_requested',
  'subagent.start',
  'subagent.thinking',
  'subagent.tool',
  'subagent.progress',
  'subagent.complete'
])

// Anonymous progress events that carry todos but no name still belong to the
// todo stream; named todo events are obviously routed there too.
export function toTodoPayload(payload: GatewayEventPayload | undefined): GatewayEventPayload | undefined {
  if (!payload) {
    return undefined
  }

  const isTodo = payload.name === 'todo' || (!payload.name && Object.hasOwn(payload, 'todos'))

  return isTodo ? { ...payload, name: 'todo', tool_id: payload.tool_id || 'todo-live' } : undefined
}

function asRecord(value: unknown): Record<string, unknown> {
  return value && typeof value === 'object' && !Array.isArray(value) ? (value as Record<string, unknown>) : {}
}

function parseMaybeRecord(value: unknown): Record<string, unknown> {
  if (typeof value === 'string') {
    try {
      return asRecord(JSON.parse(value))
    } catch {
      return {}
    }
  }

  return asRecord(value)
}

const firstString = (...candidates: unknown[]): string => {
  for (const v of candidates) {
    if (typeof v === 'string' && v) {
      return v
    }
  }

  return ''
}

export function delegateTaskPayloads(
  payload: GatewayEventPayload | undefined,
  phase: 'running' | 'complete',
  sourceEventType?: string
): Record<string, unknown>[] {
  if (payload?.name !== 'delegate_task') {
    return []
  }

  const args = parseMaybeRecord(payload.args ?? payload.input)
  const result = parseMaybeRecord(payload.result)
  const rawTasks = Array.isArray(args.tasks) ? args.tasks : []
  const tasks = rawTasks.length ? rawTasks.map(parseMaybeRecord) : [args]
  const status = phase === 'complete' ? (payload.error ? 'failed' : 'completed') : 'running'
  const toolId = payload.tool_id || payload.tool_call_id || payload.id || 'delegate_task'
  const progressText = firstString(payload.preview, payload.message, payload.context)

  const eventType =
    phase === 'complete'
      ? 'subagent.complete'
      : sourceEventType === 'tool.start'
        ? 'subagent.start'
        : 'subagent.progress'

  return tasks.map((task, index) => {
    const goal = firstString(task.goal, args.goal, payload.context) || 'Delegated task'
    const summary = firstString(result.summary, payload.summary, payload.message)

    return {
      depth: 0,
      duration_seconds: payload.duration_s,
      goal,
      status,
      subagent_id: `delegate-tool:${toolId}:${index}`,
      summary: summary || undefined,
      task_count: tasks.length,
      task_index: index,
      text: eventType === 'subagent.progress' ? progressText || goal : undefined,
      tool_name: eventType === 'subagent.start' ? 'delegate_task' : undefined,
      tool_preview: eventType === 'subagent.start' ? progressText : undefined,
      toolsets: Array.isArray(task.toolsets) ? task.toolsets : Array.isArray(args.toolsets) ? args.toolsets : [],
      event_type: eventType,
      output_tail:
        phase === 'complete' && summary
          ? [{ is_error: Boolean(payload.error), preview: summary, tool: 'delegate_task' }]
          : undefined
    }
  })
}