import type { BackgroundTask } from "../../../features/background-agent"
import type { BackgroundOutputClient } from "../types"
import { formatDuration, truncateText, formatMessageTime } from "./utils"
import { extractMessages, getErrorMessage, type BackgroundOutputMessagesResult, type FullSessionMessage, extractToolResultText } from "./message-processing"
import { consumeNewMessages } from "../../../shared/session-cursor"

const MAX_MESSAGE_LIMIT = 100
const THINKING_MAX_CHARS = 2000

export function formatTaskStatus(task: BackgroundTask): string {
  let duration: string
  if (task.status === "pending" && task.queuedAt) {
    duration = formatDuration(task.queuedAt, undefined)
  } else if (task.startedAt) {
    duration = formatDuration(task.startedAt, task.completedAt)
  } else {
    duration = "N/A"
  }
  const promptPreview = truncateText(task.prompt, 500)
  
  let progressSection = ""
  if (task.progress?.lastTool) {
    progressSection = `\n| Last tool | ${task.progress.lastTool} |`
  }

  let lastMessageSection = ""
  if (task.progress?.lastMessage) {
    const truncated = truncateText(task.progress.lastMessage, 500)
    const messageTime = task.progress.lastMessageAt 
      ? task.progress.lastMessageAt.toISOString()
      : "N/A"
    lastMessageSection = `

## Last Message (${messageTime})

\`\`\`
${truncated}
\`\`\``
  }

  let statusNote = ""
  if (task.status === "pending") {
    statusNote = `

> **Queued**: Task is waiting for a concurrency slot to become available.`
  } else if (task.status === "running") {
    statusNote = `

> **Note**: No need to wait explicitly - the system will notify you when this task completes.`
  } else if (task.status === "error") {
    statusNote = `

> **Failed**: The task encountered an error. Check the last message for details.`
  }

  const durationLabel = task.status === "pending" ? "Queued for" : "Duration"

  return `# Task Status

| Field | Value |
|-------|-------|
| Task ID | \`${task.id}\` |
| Description | ${task.description} |
| Agent | ${task.agent} |
| Status | **${task.status}** |
| ${durationLabel} | ${duration} |
| Session ID | \`${task.sessionID}\` |${progressSection}
${statusNote}
## Original Prompt

\`\`\`
${promptPreview}
\`\`\`${lastMessageSection}`
}

export async function formatTaskResult(task: BackgroundTask, client: BackgroundOutputClient): Promise<string> {
  if (!task.sessionID) {
    return `Error: Task has no sessionID`
  }
  
  const messagesResult: BackgroundOutputMessagesResult = await client.session.messages({
    path: { id: task.sessionID },
  })

  const errorMessage = getErrorMessage(messagesResult)
  if (errorMessage) {
    return `Error fetching messages: ${errorMessage}`
  }

  const messages = extractMessages(messagesResult)

  if (!Array.isArray(messages) || messages.length === 0) {
    return `Task Result

Task ID: ${task.id}
Description: ${task.description}
Duration: ${formatDuration(task.startedAt ?? new Date(), task.completedAt)}
Session ID: ${task.sessionID}

---

(No messages found)`
  }

  // Include both assistant messages AND tool messages
  // Tool results (grep, glob, bash output) come from role "tool"
  const relevantMessages = messages.filter(
    (m) => m.info?.role === "assistant" || m.info?.role === "tool"
  )

  if (relevantMessages.length === 0) {
    return `Task Result

Task ID: ${task.id}
Description: ${task.description}
Duration: ${formatDuration(task.startedAt ?? new Date(), task.completedAt)}
Session ID: ${task.sessionID}

---

(No assistant or tool response found)`
  }

  // Sort by time ascending (oldest first) to process messages in order
  const sortedMessages = [...relevantMessages].sort((a, b) => {
    const timeA = String((a as { info?: { time?: string } }).info?.time ?? "")
    const timeB = String((b as { info?: { time?: string } }).info?.time ?? "")
    return timeA.localeCompare(timeB)
  })
  
  const newMessages = consumeNewMessages(task.sessionID, sortedMessages)
  if (newMessages.length === 0) {
    const duration = formatDuration(task.startedAt ?? new Date(), task.completedAt)
    return `Task Result

Task ID: ${task.id}
Description: ${task.description}
Duration: ${duration}
Session ID: ${task.sessionID}

---

(No new output since last check)`
  }

  // Extract content from ALL messages, not just the last one
  // Tool results may be in earlier messages while the final message is empty
  const extractedContent: string[] = []
  
  for (const message of newMessages) {
    for (const part of message.parts ?? []) {
      // Handle both "text" and "reasoning" parts (thinking models use "reasoning")
      if ((part.type === "text" || part.type === "reasoning") && part.text) {
        extractedContent.push(part.text)
      } else if (part.type === "tool_result") {
        // Tool results contain the actual output from tool calls
        const toolResult = part as { content?: string | Array<{ type: string; text?: string }> }
        if (typeof toolResult.content === "string" && toolResult.content) {
          extractedContent.push(toolResult.content)
        } else if (Array.isArray(toolResult.content)) {
          // Handle array of content blocks
          for (const block of toolResult.content) {
            // Handle both "text" and "reasoning" parts (thinking models use "reasoning")
            if ((block.type === "text" || block.type === "reasoning") && block.text) {
              extractedContent.push(block.text)
            }
          }
        }
      }
    }
  }
  
  const textContent = extractedContent
    .filter((text) => text.length > 0)
    .join("\n\n")

  const duration = formatDuration(task.startedAt ?? new Date(), task.completedAt)

  return `Task Result

Task ID: ${task.id}
Description: ${task.description}
Duration: ${duration}
Session ID: ${task.sessionID}

---

${textContent || "(No text output)"}`
}

export async function formatFullSession(
  task: BackgroundTask,
  client: BackgroundOutputClient,
  options: {
    includeThinking: boolean
    messageLimit?: number
    sinceMessageId?: string
    includeToolResults: boolean
    thinkingMaxChars?: number
  }
): Promise<string> {
  if (!task.sessionID) {
    return formatTaskStatus(task)
  }

  const messagesResult: BackgroundOutputMessagesResult = await client.session.messages({
    path: { id: task.sessionID },
  })

  const errorMessage = getErrorMessage(messagesResult)
  if (errorMessage) {
    return `Error fetching messages: ${errorMessage}`
  }

  const rawMessages = extractMessages(messagesResult)
  if (!Array.isArray(rawMessages)) {
    return "Error fetching messages: invalid response"
  }

  const sortedMessages = [...(rawMessages as FullSessionMessage[])].sort((a, b) => {
    const timeA = String(a.info?.time ?? "")
    const timeB = String(b.info?.time ?? "")
    return timeA.localeCompare(timeB)
  })

  let filteredMessages = sortedMessages

  if (options.sinceMessageId) {
    const index = filteredMessages.findIndex((message) => message.id === options.sinceMessageId)
    if (index === -1) {
      return `Error: since_message_id not found: ${options.sinceMessageId}`
    }
    filteredMessages = filteredMessages.slice(index + 1)
  }

  const includeThinking = options.includeThinking
  const includeToolResults = options.includeToolResults
  const thinkingMaxChars = options.thinkingMaxChars ?? THINKING_MAX_CHARS

  const normalizedMessages: FullSessionMessage[] = []
  for (const message of filteredMessages) {
    const parts = (message.parts ?? []).filter((part) => {
      if (part.type === "thinking" || part.type === "reasoning") {
        return includeThinking
      }
      if (part.type === "tool_result") {
        return includeToolResults
      }
      return part.type === "text"
    })

    if (parts.length === 0) {
      continue
    }

    normalizedMessages.push({ ...message, parts })
  }

  const limit = typeof options.messageLimit === "number"
    ? Math.min(options.messageLimit, MAX_MESSAGE_LIMIT)
    : undefined
  const hasMore = limit !== undefined && normalizedMessages.length > limit
  const visibleMessages = limit !== undefined
    ? normalizedMessages.slice(0, limit)
    : normalizedMessages

  const lines: string[] = []
  lines.push("# Full Session Output")
  lines.push("")
  lines.push(`Task ID: ${task.id}`)
  lines.push(`Description: ${task.description}`)
  lines.push(`Status: ${task.status}`)
  lines.push(`Session ID: ${task.sessionID}`)
  lines.push(`Total messages: ${normalizedMessages.length}`)
  lines.push(`Returned: ${visibleMessages.length}`)
  lines.push(`Has more: ${hasMore ? "true" : "false"}`)
  lines.push("")
  lines.push("## Messages")

  if (visibleMessages.length === 0) {
    lines.push("")
    lines.push("(No messages found)")
    return lines.join("\n")
  }

  for (const message of visibleMessages) {
    const role = message.info?.role ?? "unknown"
    const agent = message.info?.agent ? ` (${message.info.agent})` : ""
    const time = formatMessageTime(message.info?.time)
    const idLabel = message.id ? ` id=${message.id}` : ""
    lines.push("")
    lines.push(`[${role}${agent}] ${time}${idLabel}`)

    for (const part of message.parts ?? []) {
      if (part.type === "text" && part.text) {
        lines.push(part.text.trim())
      } else if (part.type === "thinking" && part.thinking) {
        lines.push(`[thinking] ${truncateText(part.thinking, thinkingMaxChars)}`)
      } else if (part.type === "reasoning" && part.text) {
        lines.push(`[thinking] ${truncateText(part.text, thinkingMaxChars)}`)
      } else if (part.type === "tool_result") {
        const toolTexts = extractToolResultText(part)
        for (const toolText of toolTexts) {
          lines.push(`[tool result] ${toolText}`)
        }
      }
    }
  }

  return lines.join("\n")
}