import React, { useCallback, useState } from 'react'
import { useTerminalSize } from 'src/hooks/useTerminalSize.js'
import {
  type CodeSession,
  fetchCodeSessionsFromSessionsAPI,
} from 'src/utils/teleport/api.js'
// eslint-disable-next-line custom-rules/prefer-use-keybindings -- raw j/k/arrow list navigation
import { Box, Text, useInput } from '@anthropic/ink'
import { useKeybinding } from '../keybindings/useKeybinding.js'
import { useShortcutDisplay } from '../keybindings/useShortcutDisplay.js'
import { logForDebugging } from '../utils/debug.js'
import { detectCurrentRepository } from '../utils/detectRepository.js'
import { formatRelativeTime } from '../utils/format.js'
import { ConfigurableShortcutHint } from './ConfigurableShortcutHint.js'
import { Select } from './CustomSelect/index.js'
import { Byline, KeyboardShortcutHint } from '@anthropic/ink'
import { Spinner } from './Spinner.js'
import { TeleportError } from './TeleportError.js'

type Props = {
  onSelect: (session: CodeSession) => void
  onCancel: () => void
  isEmbedded?: boolean
}

type LoadErrorType = 'network' | 'auth' | 'api' | 'other'

const UPDATED_STRING = 'Updated'
const SPACE_BETWEEN_TABLE_COLUMNS = '  '

export function ResumeTask({
  onSelect,
  onCancel,
  isEmbedded = false,
}: Props): React.ReactNode {
  const { rows } = useTerminalSize()
  const [sessions, setSessions] = useState<CodeSession[]>([])
  const [currentRepo, setCurrentRepo] = useState<string | null>(null)

  const [loading, setLoading] = useState(true)
  const [loadErrorType, setLoadErrorType] = useState<LoadErrorType | null>(null)
  const [retrying, setRetrying] = useState(false)

  const [hasCompletedTeleportErrorFlow, setHasCompletedTeleportErrorFlow] =
    useState(false)

  // Track focused index for scroll position display in title
  const [focusedIndex, setFocusedIndex] = useState(1)

  const escKey = useShortcutDisplay('confirm:no', 'Confirmation', 'Esc')

  const loadSessions = useCallback(async () => {
    try {
      setLoading(true)
      setLoadErrorType(null)

      // Detect current repository
      const detectedRepo = await detectCurrentRepository()
      setCurrentRepo(detectedRepo)
      logForDebugging(`Current repository: ${detectedRepo || 'not detected'}`)

      const codeSessions = await fetchCodeSessionsFromSessionsAPI()

      // Filter sessions by current repository if detected
      let filteredSessions = codeSessions
      if (detectedRepo) {
        filteredSessions = codeSessions.filter(session => {
          if (!session.repo) return false
          const sessionRepo = `${session.repo.owner.login}/${session.repo.name}`
          return sessionRepo === detectedRepo
        })
        logForDebugging(
          `Filtered ${filteredSessions.length} sessions for repo ${detectedRepo} from ${codeSessions.length} total`,
        )
      }

      // Sort by updated_at (newest first)
      const sortedSessions = [...filteredSessions].sort((a, b) => {
        const dateA = new Date(a.updated_at)
        const dateB = new Date(b.updated_at)
        return dateB.getTime() - dateA.getTime()
      })

      setSessions(sortedSessions)
    } catch (err) {
      const errorMessage = err instanceof Error ? err.message : String(err)
      logForDebugging(`Error loading code sessions: ${errorMessage}`)
      setLoadErrorType(determineErrorType(errorMessage))
    } finally {
      setLoading(false)
      setRetrying(false)
    }
  }, [])

  const handleRetry = () => {
    setRetrying(true)
    void loadSessions()
  }

  // Handle escape via keybinding
  useKeybinding('confirm:no', onCancel, { context: 'Confirmation' })

  useInput((input, key) => {
    // We need to handle ctrl+c in case we don't render a <Select>
    if (key.ctrl && input === 'c') {
      onCancel()
      return
    }

    // Handle retry in error state with 'ctrl+r'
    if (key.ctrl && input === 'r' && loadErrorType) {
      handleRetry()
      return
    }

    // Handle enter key for error states to allow continuation with regular teleport
    if (loadErrorType !== null && key.return) {
      onCancel() // This will continue with regular teleport flow
      return
    }
  })

  const handleErrorComplete = useCallback(() => {
    setHasCompletedTeleportErrorFlow(true)
    void loadSessions()
  }, [setHasCompletedTeleportErrorFlow, loadSessions])

  // Show error dialog if needed
  if (!hasCompletedTeleportErrorFlow) {
    return <TeleportError onComplete={handleErrorComplete} />
  }

  if (loading) {
    return (
      <Box flexDirection="column" padding={1}>
        <Box flexDirection="row">
          <Spinner />
          <Text bold>Loading Claude Code sessions…</Text>
        </Box>
        <Text dimColor>
          {retrying ? 'Retrying…' : 'Fetching your Claude Code sessions…'}
        </Text>
      </Box>
    )
  }

  if (loadErrorType) {
    return (
      <Box flexDirection="column" padding={1}>
        <Text bold color="error">
          Error loading Claude Code sessions
        </Text>

        {renderErrorSpecificGuidance(loadErrorType)}

        <Text dimColor>
          Press <Text bold>Ctrl+R</Text> to retry · Press{' '}
          <Text bold>{escKey}</Text> to cancel
        </Text>
      </Box>
    )
  }

  if (sessions.length === 0) {
    return (
      <Box flexDirection="column" padding={1}>
        <Text bold>
          No Claude Code sessions found
          {currentRepo && <Text> for {currentRepo}</Text>}
        </Text>
        <Box marginTop={1}>
          <Text dimColor>
            Press <Text bold>{escKey}</Text> to cancel
          </Text>
        </Box>
      </Box>
    )
  }

  const sessionMetadata = sessions.map(session => ({
    ...session,
    timeString: formatRelativeTime(new Date(session.updated_at)),
  }))
  const maxTimeStringLength = Math.max(
    UPDATED_STRING.length,
    ...sessionMetadata.map(meta => meta.timeString.length),
  )

  const options = sessionMetadata.map(({ timeString, title, id }) => {
    const paddedTime = timeString.padEnd(maxTimeStringLength, ' ')

    // TODO: include branch name when API returns it
    return {
      label: `${paddedTime}  ${title}`,
      value: id,
    }
  })

  // Adjust layout for embedded vs full-screen rendering
  // Overhead: padding (2) + title (1) + marginY (2) + header (1) + footer (1) = 7
  const layoutOverhead = 7
  const maxVisibleOptions = Math.max(
    1,
    isEmbedded
      ? Math.min(sessions.length, 5, rows - 6 - layoutOverhead)
      : Math.min(sessions.length, rows - 1 - layoutOverhead),
  )
  const maxHeight = maxVisibleOptions + layoutOverhead

  // Show scroll position in title when list needs scrolling
  const showScrollPosition = sessions.length > maxVisibleOptions

  return (
    <Box flexDirection="column" padding={1} height={maxHeight}>
      <Text bold>
        Select a session to resume
        {showScrollPosition && (
          <Text dimColor>
            {' '}
            ({focusedIndex} of {sessions.length})
          </Text>
        )}
        {currentRepo && <Text dimColor> ({currentRepo})</Text>}:
      </Text>
      <Box flexDirection="column" marginTop={1} flexGrow={1}>
        <Box marginLeft={2}>
          <Text bold>
            {UPDATED_STRING.padEnd(maxTimeStringLength, ' ')}
            {SPACE_BETWEEN_TABLE_COLUMNS}
            {'Session Title'}
          </Text>
        </Box>
        <Select
          visibleOptionCount={maxVisibleOptions}
          options={options}
          onChange={value => {
            const session = sessions.find(s => s.id === value)
            if (session) {
              onSelect(session)
            }
          }}
          onFocus={value => {
            const index = options.findIndex(o => o.value === value)
            if (index >= 0) {
              setFocusedIndex(index + 1)
            }
          }}
        />
      </Box>
      <Box flexDirection="row">
        <Text dimColor>
          <Byline>
            <KeyboardShortcutHint shortcut="↑/↓" action="select" />
            <KeyboardShortcutHint shortcut="Enter" action="confirm" />
            <ConfigurableShortcutHint
              action="confirm:no"
              context="Confirmation"
              fallback="Esc"
              description="cancel"
            />
          </Byline>
        </Text>
      </Box>
    </Box>
  )
}

/**
 * Determines the type of error based on the error message
 */
function determineErrorType(errorMessage: string): LoadErrorType {
  const message = errorMessage.toLowerCase()

  if (
    message.includes('fetch') ||
    message.includes('network') ||
    message.includes('timeout')
  ) {
    return 'network'
  }

  if (
    message.includes('auth') ||
    message.includes('token') ||
    message.includes('permission') ||
    message.includes('oauth') ||
    message.includes('not authenticated') ||
    message.includes('/login') ||
    message.includes('console account') ||
    message.includes('403')
  ) {
    return 'auth'
  }

  if (
    message.includes('api') ||
    message.includes('rate limit') ||
    message.includes('500') ||
    message.includes('529')
  ) {
    return 'api'
  }

  return 'other'
}

/**
 * Renders error-specific troubleshooting guidance
 */
function renderErrorSpecificGuidance(
  errorType: LoadErrorType,
): React.ReactNode {
  switch (errorType) {
    case 'network':
      return (
        <Box marginY={1} flexDirection="column">
          <Text dimColor>Check your internet connection</Text>
        </Box>
      )

    case 'auth':
      return (
        <Box marginY={1} flexDirection="column">
          <Text dimColor>Teleport requires a Claude account</Text>
          <Text dimColor>
            Run <Text bold>/login</Text> and select &quot;Claude account with
            subscription&quot;
          </Text>
        </Box>
      )

    case 'api':
      return (
        <Box marginY={1} flexDirection="column">
          <Text dimColor>Sorry, Claude encountered an error</Text>
        </Box>
      )

    case 'other':
      return (
        <Box marginY={1} flexDirection="row">
          <Text dimColor>Sorry, Claude Code encountered an error</Text>
        </Box>
      )
  }
}