import { FormEvent, useMemo, useRef, useState } from 'react'
import {
  PRIMARY_FOCUS_AREA_GEOJSON,
  PRIMARY_FOCUS_AREA_NAME,
  PRIMARY_FOCUS_REGION,
  NATIONAL_WORKSPACE_PROJECT_NAME,
  REGIONAL_WORKSPACE_PROJECT_NAME,
  isPrimaryFocusMunicipalityBoundaryDataset,
  isPrimaryFocusMunicipalityProject,
  isPrimaryFocusProject,
  isPrimaryFocusProjectData,
} from '../config/primaryFocus'
import { areasApi } from '../services/api/areas'
import { datasetsApi } from '../services/api/datasets'
import { projectsApi } from '../services/api/projects'
import type {
  AreaCreate,
  AreaListResponse,
  AreaRead,
  DatasetCreateResponse,
  DatasetListResponse,
  ProjectCreate,
  ProjectRead,
} from '../types'

const DEMO_PROJECT_NAME = 'GeoIntel Demo - Building QA'

function isDemoProject(project: ProjectRead): boolean {
  return project.name === DEMO_PROJECT_NAME
}

function hasMappedAnalysisContext(
  data: { areas: AreaRead[]; datasets: DatasetCreateResponse[] },
): boolean {
  const hasRasterDataset = data.datasets.some((dataset) => dataset.dataset_type === 'raster')
  const hasVectorDataset = data.datasets.some(
    (dataset) => dataset.dataset_type === 'vector' || dataset.dataset_type === 'geojson',
  )
  return data.areas.length > 0 && hasRasterDataset && hasVectorDataset
}

export function useProjectWorkspace() {
  const [projects, setProjects] = useState<ProjectRead[]>([])
  const [selectedProjectId, setSelectedProjectId] = useState<string | null>(null)
  const [areas, setAreas] = useState<AreaRead[]>([])
  const [datasets, setDatasets] = useState<DatasetCreateResponse[]>([])
  const [loadingProjects, setLoadingProjects] = useState(false)
  const [loadingAreas, setLoadingAreas] = useState(false)
  const [loadingDatasets, setLoadingDatasets] = useState(false)
  const [archivingProjectId, setArchivingProjectId] = useState<string | null>(null)
  const [errorMessage, setErrorMessage] = useState<string | null>(null)
  const projectDataRequestSequence = useRef(0)

  const [projectForm, setProjectForm] = useState<ProjectCreate>({
    name: '',
    description: '',
    region: PRIMARY_FOCUS_REGION,
  })
  const [areaForm, setAreaForm] = useState({
    name: PRIMARY_FOCUS_AREA_NAME,
    geometry: PRIMARY_FOCUS_AREA_GEOJSON,
    crs: 'EPSG:4326',
  })

  const selectedProject = useMemo(
    () => projects.find((project) => project.id === selectedProjectId) ?? null,
    [projects, selectedProjectId],
  )

  const fetchProjectData = async (projectId: string): Promise<{ areas: AreaRead[]; datasets: DatasetCreateResponse[] }> => {
    const [areaResponse, datasetResponse]: [AreaListResponse, DatasetListResponse] = await Promise.all([
      areasApi.list(projectId),
      datasetsApi.list(projectId),
    ])
    return { areas: areaResponse.items, datasets: datasetResponse.items }
  }

  const pickInitialProjectId = async (items: ProjectRead[], preferredProjectId?: string | null) => {
    if (preferredProjectId && items.some((project) => project.id === preferredProjectId)) {
      return preferredProjectId
    }
    if (selectedProjectId && items.some((project) => project.id === selectedProjectId)) {
      return selectedProjectId
    }
    const nationalProject = items.find((project) => project.name === NATIONAL_WORKSPACE_PROJECT_NAME)
    if (nationalProject) {
      try {
        const data = await fetchProjectData(nationalProject.id)
        if (data.areas.length > 0 && data.datasets.some((dataset) => dataset.status === 'ready')) {
          return nationalProject.id
        }
      } catch {
        // Continue with regional and municipality fallbacks while national data is unavailable.
      }
    }
    const regionalProject = items.find((project) => project.name === REGIONAL_WORKSPACE_PROJECT_NAME)
    if (regionalProject) {
      try {
        const data = await fetchProjectData(regionalProject.id)
        if (data.areas.length > 0 && data.datasets.some((dataset) => dataset.status === 'ready')) {
          return regionalProject.id
        }
      } catch {
        // Continue with the municipality and completeness fallbacks when regional data is unavailable.
      }
    }
    const municipalityProject = items.find(isPrimaryFocusMunicipalityProject)
    if (municipalityProject) {
      try {
        const data = await fetchProjectData(municipalityProject.id)
        if (data.areas.length > 0 && data.datasets.some(isPrimaryFocusMunicipalityBoundaryDataset)) {
          return municipalityProject.id
        }
      } catch {
        // Continue with the normal completeness ranking if the canonical workspace is temporarily unavailable.
      }
    }
    const primaryProjects = items.filter(isPrimaryFocusProject)
    const demoProjects = items.filter(isDemoProject)
    const candidates = Array.from(
      new Map(
        [...primaryProjects, ...demoProjects, ...items].map((project) => [project.id, project]),
      ).values(),
    ).slice(0, 12)
    const inspectedCandidates: Array<{
      project: ProjectRead
      data: { areas: AreaRead[]; datasets: DatasetCreateResponse[] }
    }> = []
    for (const project of candidates) {
      try {
        const data = await fetchProjectData(project.id)
        inspectedCandidates.push({ project, data })
        if (
          isPrimaryFocusProjectData(project, data.datasets) &&
          hasMappedAnalysisContext(data)
        ) {
          return project.id
        }
      } catch {
        // Project list should still render if a candidate's detail endpoints are temporarily unavailable.
      }
    }
    const primaryContext = inspectedCandidates.find(
      ({ project, data }) =>
        data.datasets.length > 0 && isPrimaryFocusProjectData(project, data.datasets),
    )
    if (primaryContext) {
      return primaryContext.project.id
    }
    const completeContext = inspectedCandidates.find(
      ({ data }) => data.areas.length > 0 && data.datasets.length > 0,
    )
    return completeContext?.project.id ?? primaryProjects[0]?.id ?? demoProjects[0]?.id ?? items[0]?.id ?? null
  }

  const loadProjects = async (preferredProjectId?: string | null) => {
    setLoadingProjects(true)
    setErrorMessage(null)
    try {
      const [response, nationalResponse, canonicalResponse] = await Promise.all([
        projectsApi.list(),
        projectsApi.list({ name: NATIONAL_WORKSPACE_PROJECT_NAME, limit: 1 }),
        projectsApi.list({ name: REGIONAL_WORKSPACE_PROJECT_NAME, limit: 1 }),
      ])
      const regionalItems = [...canonicalResponse.items, ...response.items]
      const items = Array.from(
        new Map(
          [...nationalResponse.items, ...regionalItems].map((project) => [project.id, project]),
        ).values(),
      )
      setProjects(items)
      const nextProjectId = await pickInitialProjectId(items, preferredProjectId)
      if (nextProjectId && nextProjectId !== selectedProjectId) {
        setSelectedProjectId(nextProjectId)
      }
    } catch (error) {
      setErrorMessage(error instanceof Error ? error.message : 'Werkruimtes konden niet worden geladen')
    } finally {
      setLoadingProjects(false)
    }
  }

  const loadProjectData = async (projectId: string) => {
    const requestId = ++projectDataRequestSequence.current
    setLoadingAreas(true)
    setLoadingDatasets(true)
    setErrorMessage(null)
    try {
      const projectData = await fetchProjectData(projectId)
      if (requestId !== projectDataRequestSequence.current) {
        return null
      }
      setAreas(projectData.areas)
      setDatasets(projectData.datasets)
      return projectData
    } catch (error) {
      if (requestId === projectDataRequestSequence.current) {
        setErrorMessage(error instanceof Error ? error.message : 'De gegevens van de werkruimte konden niet worden geladen')
      }
      return null
    } finally {
      if (requestId === projectDataRequestSequence.current) {
        setLoadingAreas(false)
        setLoadingDatasets(false)
      }
    }
  }

  const createProject = async (event: FormEvent) => {
    event.preventDefault()
    if (!projectForm.name.trim()) {
      setErrorMessage('Geef een naam voor de werkruimte op')
      return
    }
    try {
      const createdProject = await projectsApi.create({
        name: projectForm.name.trim(),
        description: projectForm.description?.trim() || undefined,
        region: projectForm.region?.trim() || PRIMARY_FOCUS_REGION,
      })
      setProjectForm((previous) => ({ ...previous, name: '', description: '' }))
      setSelectedProjectId(createdProject.id)
      await loadProjects(createdProject.id)
    } catch (error) {
      setErrorMessage(error instanceof Error ? error.message : 'De werkruimte kon niet worden aangemaakt')
    }
  }

  const createArea = async (event: FormEvent) => {
    event.preventDefault()
    if (!selectedProjectId) {
      setErrorMessage('Kies eerst een werkruimte')
      return
    }
    let geometry: AreaCreate['geometry']
    try {
      geometry = JSON.parse(areaForm.geometry) as AreaCreate['geometry']
    } catch {
      setErrorMessage('De opgegeven GeoJSON-geometrie is ongeldig')
      return
    }
    try {
      await areasApi.create(selectedProjectId, {
        name: areaForm.name,
        crs: areaForm.crs,
        geometry,
      })
      await loadProjectData(selectedProjectId)
      setAreaForm((previous) => ({ ...previous, name: '' }))
    } catch (error) {
      setErrorMessage(error instanceof Error ? error.message : 'Het gebied kon niet worden aangemaakt')
    }
  }

  const archiveProject = async (projectId: string) => {
    setArchivingProjectId(projectId)
    setErrorMessage(null)
    try {
      await projectsApi.update(projectId, { status: 'archived' })
      if (selectedProjectId === projectId) {
        setSelectedProjectId(null)
        resetProjectData()
      }
      await loadProjects()
    } catch (error) {
      setErrorMessage(error instanceof Error ? error.message : 'De werkruimte kon niet worden gearchiveerd')
    } finally {
      setArchivingProjectId(null)
    }
  }

  const resetProjectData = () => {
    projectDataRequestSequence.current += 1
    setAreas([])
    setDatasets([])
  }

  return {
    projects,
    selectedProject,
    selectedProjectId,
    areas,
    datasets,
    loadingProjects,
    loadingAreas,
    loadingDatasets,
    archivingProjectId,
    errorMessage,
    projectForm,
    areaForm,
    loadProjects,
    loadProjectData,
    createProject,
    createArea,
    archiveProject,
    resetProjectData,
    setSelectedProjectId,
    setErrorMessage,
    setProjectForm,
    setAreaForm,
  }
}