import { useQuery } from '@tanstack/react-query'
import { useParams } from 'common'
import { useCallback, useMemo } from 'react'

import {
  formatGitHubConfigDecodeMessage,
  fromDashboardProjectConfig,
  getConfigDriftSummary,
  type GitHubConfigDriftSummary,
} from '@/components/interfaces/ConfigDrift/github-config-drift'
import type { Branch } from '@/data/branches/branches-query'
import { useBranchesQuery } from '@/data/branches/branches-query'
import { useGitHubConfigQuery } from '@/data/config/github-config-query'
import { projectConfigV2QueryOptions } from '@/data/config/project-config-query'
import { useProjectGitHubConnectionQuery } from '@/data/integrations/github-connections-query'
import { useSelectedProjectQuery } from '@/hooks/misc/useSelectedProject'
import { IS_PLATFORM } from '@/lib/constants'

const EMPTY_SUMMARY: GitHubConfigDriftSummary = {
  driftedFields: [],
  matchedFields: [],
  unmanagedFields: [],
}

type ConfigDriftMemoResult =
  | { status: 'success'; summary: GitHubConfigDriftSummary }
  | { status: 'error'; source: 'project-config' | 'config-toml'; error: Error }

export function getGitBranchName(branch?: Branch): string | undefined {
  return branch?.git_branch?.trim() || (branch?.is_default ? undefined : branch?.name?.trim())
}

export function useSelectedGitHubConfigDrift() {
  const { ref: projectRef } = useParams()
  const projectQuery = useSelectedProjectQuery()
  const project = projectQuery.data
  const parentProjectRef = project?.parentRef ?? projectRef
  const shouldLoad = IS_PLATFORM && Boolean(projectRef) && Boolean(project)

  const branchesQuery = useBranchesQuery({ projectRef: parentProjectRef }, { enabled: shouldLoad })
  const connectionQuery = useProjectGitHubConnectionQuery({ ref: parentProjectRef })
  const connection = connectionQuery.data
  const hasConnection = connection !== undefined
  const branches = branchesQuery.data ?? []
  const selectedBranch = branches.find((branch) => branch.project_ref === projectRef)
  const gitBranch = getGitBranchName(selectedBranch)
  const queriesEnabled =
    shouldLoad && branchesQuery.isSuccess && connectionQuery.isSuccess && hasConnection

  const projectConfigQuery = useQuery({
    ...projectConfigV2QueryOptions({ projectRef }),
    enabled: queriesEnabled,
    staleTime: 30_000,
  })
  const githubConfigQuery = useGitHubConfigQuery(
    { connectionId: connection?.id, branch: gitBranch },
    { enabled: queriesEnabled }
  )

  const { refetch: branchesRefetch } = branchesQuery
  const { refetch: connectionRefetch } = connectionQuery
  const { refetch: projectConfigRefetch } = projectConfigQuery
  const { refetch: githubConfigRefetch } = githubConfigQuery

  const refetch = useCallback(
    () =>
      Promise.all([
        branchesRefetch(),
        connectionRefetch(),
        projectConfigRefetch(),
        githubConfigRefetch(),
      ]),
    [branchesRefetch, connectionRefetch, projectConfigRefetch, githubConfigRefetch]
  )

  const driftResult = useMemo((): ConfigDriftMemoResult => {
    let dashboardConfig
    try {
      dashboardConfig = fromDashboardProjectConfig(projectConfigQuery.data?.attributes)
    } catch (error) {
      console.error('Failed to read project configuration:', error)
      return {
        status: 'error',
        source: 'project-config',
        error: new Error('Could not read the project configuration returned by the API.'),
      }
    }

    const result = getConfigDriftSummary({
      dashboardConfig,
      githubConfig: githubConfigQuery.data?.config,
    })
    if (result.status === 'invalid-config') {
      return {
        status: 'error',
        source: 'config-toml',
        error: new Error(formatGitHubConfigDecodeMessage(result.issues)),
      }
    }

    return { status: 'success', summary: result.summary }
  }, [projectConfigQuery.data?.attributes, githubConfigQuery.data?.config])

  const summary = driftResult.status === 'success' ? driftResult.summary : EMPTY_SUMMARY
  const conversionError = driftResult.status === 'error' ? driftResult.error : undefined

  const activeQueries = [
    projectQuery,
    ...(shouldLoad ? [branchesQuery, connectionQuery] : []),
    ...(shouldLoad && hasConnection ? [projectConfigQuery, githubConfigQuery] : []),
  ]

  const isReady =
    shouldLoad && hasConnection && projectConfigQuery.isSuccess && githubConfigQuery.isSuccess
  const issueCount = summary.driftedFields.length
  const queryError = activeQueries.find((query) => query.error)?.error
  let errorSource: 'query' | 'project-config' | 'config-toml' | undefined = undefined
  if (queryError) {
    errorSource = 'query'
  } else if (driftResult.status === 'error') {
    errorSource = driftResult.source
  }

  return {
    requestedGitBranch: gitBranch,
    isReady,
    isPending: activeQueries.some((query) => query.isPending),
    isFetching: activeQueries.some((query) => query.isFetching),
    isError: activeQueries.some((query) => query.isError) || conversionError !== undefined,
    error: queryError ?? conversionError,
    errorSource,
    hasConfigurationIssues: isReady && issueCount > 0,
    summary,
    refetch,
  }
}