import pc from "picocolors"
import type {
  RunContext,
  EventPayload,
  SessionIdleProps,
  SessionStatusProps,
  SessionErrorProps,
  MessageUpdatedProps,
  MessagePartUpdatedProps,
  ToolExecuteProps,
  ToolResultProps,
  TuiToastShowProps,
} from "./types"
import type { EventState } from "./event-state"
import { serializeError } from "./event-formatting"
import { formatToolInputPreview } from "./tool-input-preview"
import { displayChars } from "./display-chars"

function getSessionId(props?: { sessionID?: string; sessionId?: string }): string | undefined {
  return props?.sessionID ?? props?.sessionId
}

function getInfoSessionId(props?: {
  info?: { sessionID?: string; sessionId?: string }
}): string | undefined {
  return props?.info?.sessionID ?? props?.info?.sessionId
}

function getPartSessionId(props?: {
  part?: { sessionID?: string; sessionId?: string }
}): string | undefined {
  return props?.part?.sessionID ?? props?.part?.sessionId
}

export function handleSessionIdle(ctx: RunContext, payload: EventPayload, state: EventState): void {
  if (payload.type !== "session.idle") return

  const props = payload.properties as SessionIdleProps | undefined
  if (getSessionId(props) === ctx.sessionID) {
    state.mainSessionIdle = true
  }
}

export function handleSessionStatus(ctx: RunContext, payload: EventPayload, state: EventState): void {
  if (payload.type !== "session.status") return

  const props = payload.properties as SessionStatusProps | undefined
  if (getSessionId(props) !== ctx.sessionID) return

  if (props?.status?.type === "busy") {
    state.mainSessionIdle = false
  } else if (props?.status?.type === "idle") {
    state.mainSessionIdle = true
  } else if (props?.status?.type === "retry") {
    state.mainSessionIdle = false
  }
}

export function handleSessionError(ctx: RunContext, payload: EventPayload, state: EventState): void {
  if (payload.type !== "session.error") return

  const props = payload.properties as SessionErrorProps | undefined
  if (getSessionId(props) === ctx.sessionID) {
    state.mainSessionError = true
    state.lastError = serializeError(props?.error)
    console.error(pc.red(`\n[session.error] ${state.lastError}`))
  }
}

export function handleMessagePartUpdated(ctx: RunContext, payload: EventPayload, state: EventState): void {
  if (payload.type !== "message.part.updated") return

  const props = payload.properties as MessagePartUpdatedProps | undefined
  // Current OpenCode puts sessionID inside part; legacy puts it in info
  const partSid = getPartSessionId(props)
  const infoSid = getInfoSessionId(props)
  if ((partSid ?? infoSid) !== ctx.sessionID) return

  const role = props?.info?.role ?? state.currentMessageRole
  if (role === "user") return

  const part = props?.part
  if (!part) return

  if (part.type === "text" && part.text) {
    const newText = part.text.slice(state.lastPartText.length)
    if (newText) {
      process.stdout.write(newText)
      state.hasReceivedMeaningfulWork = true
    }
    state.lastPartText = part.text
  }

  if (part.type === "tool") {
    handleToolPart(ctx, part, state)
  }
}

function handleToolPart(
  _ctx: RunContext,
  part: NonNullable<MessagePartUpdatedProps["part"]>,
  state: EventState,
): void {
  const toolName = part.tool || part.name || "unknown"
  const status = part.state?.status

  if (status === "running") {
    state.currentTool = toolName
    const inputPreview = part.state?.input
      ? formatToolInputPreview(part.state.input)
      : ""
    state.hasReceivedMeaningfulWork = true
    process.stdout.write(`\n${pc.cyan(">")} ${pc.bold(toolName)}${inputPreview}\n`)
  }

  if (status === "completed" || status === "error") {
    const output = part.state?.output || ""
    const maxLen = 200
    const preview = output.length > maxLen ? output.slice(0, maxLen) + "..." : output
    if (preview.trim()) {
      const lines = preview.split("\n").slice(0, 3)
      process.stdout.write(pc.dim(`${displayChars.treeIndent}${displayChars.treeEnd} ${lines.join(`\n${displayChars.treeJoin}`)}\n`))
    }
    state.currentTool = null
    state.lastPartText = ""
  }
}

export function handleMessageUpdated(ctx: RunContext, payload: EventPayload, state: EventState): void {
  if (payload.type !== "message.updated") return

  const props = payload.properties as MessageUpdatedProps | undefined
  if (getInfoSessionId(props) !== ctx.sessionID) return

  state.currentMessageRole = props?.info?.role ?? null
  if (props?.info?.role !== "assistant") return

  state.hasReceivedMeaningfulWork = true
  state.messageCount++
  state.lastPartText = ""

  const agent = props?.info?.agent ?? null
  const model = props?.info?.modelID ?? null
  if (agent !== state.currentAgent || model !== state.currentModel) {
    state.currentAgent = agent
    state.currentModel = model
    printAgentHeader(agent, model)
  }
}

function printAgentHeader(agent: string | null, model: string | null): void {
  if (!agent && !model) return
  const agentLabel = agent ? pc.bold(pc.magenta(agent)) : ""
  const modelLabel = model ? pc.dim(model) : ""
  const separator = agent && model ? " " : ""
  process.stdout.write(`\n${agentLabel}${separator}${modelLabel}\n`)
}

export function handleToolExecute(ctx: RunContext, payload: EventPayload, state: EventState): void {
  if (payload.type !== "tool.execute") return

  const props = payload.properties as ToolExecuteProps | undefined
  if (getSessionId(props) !== ctx.sessionID) return

  const toolName = props?.name || "unknown"
  state.currentTool = toolName
  const inputPreview = props?.input
    ? formatToolInputPreview(props.input)
    : ""

  state.hasReceivedMeaningfulWork = true
  process.stdout.write(`\n${pc.cyan(">")} ${pc.bold(toolName)}${inputPreview}\n`)
}

export function handleToolResult(ctx: RunContext, payload: EventPayload, state: EventState): void {
  if (payload.type !== "tool.result") return

  const props = payload.properties as ToolResultProps | undefined
  if (getSessionId(props) !== ctx.sessionID) return

  const output = props?.output || ""
  const maxLen = 200
  const preview = output.length > maxLen ? output.slice(0, maxLen) + "..." : output

  if (preview.trim()) {
    const lines = preview.split("\n").slice(0, 3)
    process.stdout.write(pc.dim(`${displayChars.treeIndent}${displayChars.treeEnd} ${lines.join(`\n${displayChars.treeJoin}`)}\n`))
  }

  state.currentTool = null
  state.lastPartText = ""
}

export function handleTuiToast(_ctx: RunContext, payload: EventPayload, state: EventState): void {
  if (payload.type !== "tui.toast.show") return

  const props = payload.properties as TuiToastShowProps | undefined
  const variant = props?.variant ?? "info"

  if (variant === "error") {
    const title = props?.title ? `${props.title}: ` : ""
    const message = props?.message?.trim()
    if (message) {
      state.mainSessionError = true
      state.lastError = `${title}${message}`
    }
  }
}