/**
 * useDashboardShell.js — the config-driven dashboard assembler (DOXA-LIB-2 foundation).
 *
 * Does generically what research-dashboard.vue's <script setup> did by hand: create one
 * brushing-and-linking selection bus, load the single in-memory row store, derive the
 * (formerly copy-pasted) FACET_ACC accessor map from config.facets, compute the linked
 * filteredRows + KPI strip + CSV exporter + shareable hash URL + responsive layout flags,
 * and provide() the bus/data/config so every panel injects instead of hard-coding.
 *
 * The next dashboard becomes a thin app-profile that passes a config object — no pasted
 * filter loops, no pasted accessor maps, no pasted KPI math. Declare the config once; the
 * shell wires the whole CMV (coordinated-multiple-views) surface.
 *
 *   const { bus, data, FACET_ACC, filteredRows, kpis, exporter, responsive } = useDashboardShell(config)
 *
 * Provides (inject keys for panels):
 *   - 'selectionBus'   → the pub/sub bus (filterSet + selectionSet + on/emit/setFilter/toggleSelect)
 *   - 'dashboardData'  → the row store ({ rows, rowStore, total, loading, error, stats, load })
 *   - 'dashboardConfig'→ the profile config (facets, facetRail, kpis, columns, charts, detail, search, title)
 * (mapboxToken is provided upstream by ProfileLoader; panels inject it directly.)
 *
 * Logic moved VERBATIM from research-dashboard.vue — filter predicate, KPI math, ResizeObserver
 * responsive switch, collapsible table dock, segmented mobile view, and the location.hash sync.
 * Only the SOURCE of the per-dashboard constants changed: from hard-coded → config.
 */
import { exactMatches, fuzzyMatches, resolveFuzzyValues } from '@map/components/search/fuzzy.js'
import { provide, ref, computed, watch, onMounted, onBeforeUnmount } from 'vue'
import { createSelectionBus } from './useSelectionBus.js'
import { useDashboardData } from './useDashboardData.js'
import { useCsvExport } from './useCsvExport.js'
import { useTreeLegendLabels } from './useTreeLegendLabels.js'
import { DataSourceManager } from '@map/api/DataSourceManager.js'
import sourcesConfig from '@map/api/sources.json'
import { tStatic } from '@map/i18n/index.js'

// tiny lodash-free mapValues: { k: v } -> { k: fn(v, k) }
const mapValues = (obj, fn) =>
  Object.fromEntries(Object.entries(obj || {}).map(([k, v]) => [k, fn(v, k)]))

// number formatter (same as the old inline `fmt`); exported for the profile's KPI strip.
export const fmt = (n) => (n === null || n === undefined ? '—' : Number(n).toLocaleString('en-US'))

/**
 * Build the free-text search accessors for a dashboard config (header-1 search bar).
 * config.searchKeys (facet keys) → those facet accessors; else the string columns' accessors.
 * ONE declaration reused by the shell (KPIs) AND every panel (table/map/charts/facets) so the
 * searchable text can never drift from what the panels show, and the substring match is not
 * copy-pasted into each panel (kills the very duplication DOXA-LIB-2 removed).
 */
export function buildSearchAccessors(config) {
  const FACET_ACC = mapValues(config.facets, (f) => f.get)
  const COL_ACC = Object.fromEntries((config.columns || []).map((c) => [c.key, c.get]))
  const keys = Array.isArray(config.searchKeys) ? config.searchKeys : null
  if (keys) return keys.map((k) => FACET_ACC[k] || COL_ACC[k]).filter((fn) => typeof fn === 'function')
  return (config.columns || []).filter((c) => c.type !== 'num' && typeof c.get === 'function').map((c) => c.get)
}

/**
 * Reusable predicate: does `row` match the bus's current free-text search term?
 * Returns true when there is no term (identical to pre-search behaviour). `accessors` is the
 * array from buildSearchAccessors(config). Case-insensitive substring over each accessor's value.
 */
export function makeSearchMatcher(bus, accessors) {
  // ★ FUZZY, NOT SUBSTRING (Driver 2026-09-23: "add an n to the end of a country name" must
  // still find it -- check what DX-life's search bar bakes in). DX-life runs real Fuse.js with
  // { threshold: 0.4, ignoreLocation: true, minMatchCharLength: 3 } (UupgsList.vue:288), so its
  // search tolerates typos. This matcher was a plain .includes() -- the one search surface that
  // silently lost that behaviour in the migration (measured: 'Bhutan' 13 rows, 'Bhutann' 0).
  // It now delegates to the shared fuzzyMatches() in @map fuzzy.js -- the same matcher the
  // grid's Fuse uses -- with the same DX-life options, so every search surface agrees.
  // Row-level predicates for the TIERED contract (see fuzzy.js exactMatches): the caller
  // (filterRowsBySearch below) runs the exact tier over the whole row set first and falls back
  // to the fuzzy tier only when exact yields nothing, so an exact term agrees with the facet.
  const test = (row, pred) => {
    const needle = (bus?.searchTerm?.value || '').trim()
    if (!needle) return true
    for (const acc of accessors) {
      const v = acc(row)
      if (v != null && pred(String(v), needle, { threshold: 0.4, minMatchCharLength: 3 })) return true
    }
    return false
  }
  const matcher = (row) => test(row, fuzzyMatches)
  matcher.exact = (row) => test(row, exactMatches)
  matcher.active = () => !!(bus?.searchTerm?.value || '').trim()
  matcher.term = () => (bus?.searchTerm?.value || '').trim()
  matcher.accessors = accessors
  return matcher
}

/**
 * Apply the TIERED search to a row set:
 *   1. exact substring -- an exact term returns exactly the rows the equivalent facet selects.
 *   2. facet-VALUE resolution (Driver: "Austrian or Canadian... a selection of that country --
 *      the table under the map shows the result for that country"): the term is resolved by
 *      whole-value edit distance against each accessor's DISTINCT values, and the rows returned
 *      are those carrying a resolved value -- byte-identical to picking it as a filter.
 *   3. the generic windowed fuzzy rescue, only when nothing resolves.
 */
export function filterRowsBySearch(rows, matcher) {
  if (!matcher.active()) return rows
  const exact = rows.filter(matcher.exact)
  if (exact.length) return exact
  const term = matcher.term()
  // ONE pool across every accessor's distinct values, so the GLOBAL best match wins (see
  // resolveFuzzyValues: ties at the minimal distance stay, everything farther drops --
  // 'Canadian' resolves to Canada, not to 47 rows of <=3-edit neighbours across facets).
  const distinct = new Set()
  for (const acc of matcher.accessors) for (const r of rows) { const v = acc(r); if (v != null && v !== '') distinct.add(String(v)) }
  const winners = new Set(resolveFuzzyValues(term, [...distinct], { threshold: 0.4 }))
  if (winners.size) {
    const resolved = rows.filter((r) => matcher.accessors.some((acc) => { const v = acc(r); return v != null && winners.has(String(v)) }))
    if (resolved.length) return resolved
  }
  return rows.filter(matcher)
}

/**
 * Generic KPI computation driven by config.kpis. Each kpi def declares a `kind`:
 *   count    → row count of the filtered scope (+ optional delta = hidden-by-filter count)
 *   sum      → Σ Number(row[field])
 *   pct      → round( rows.filter(test).length / rows.length * 100 )%  ('—' when empty)
 *   distinct → size of the set produced by an accessor (via config.facets[field][via], e.g. geoIso)
 * Mirrors the old statTotal/statPop/statPctUnreached/statCountries/statPraying/statAdoptedPct
 * computeds — only the definitions now come from config instead of being hand-written.
 */
function computeKpis(defs, filtered, all, FACET_ACC, config) {
  return (defs || []).map((k) => {
    let value
    let delta
    if (k.kind === 'count') {
      value = filtered.length
      if (k.showDelta) delta = Math.max(0, all.length - filtered.length)
    } else if (k.kind === 'sum') {
      value = filtered.reduce((s, r) => s + (Number(r[k.field]) || 0), 0)
    } else if (k.kind === 'pct') {
      value = filtered.length
        ? Math.round((filtered.filter(k.test).length / filtered.length) * 100) + '%'
        : '—'
    } else if (k.kind === 'distinct') {
      const acc = k.via ? config?.facets?.[k.field]?.[k.via] : FACET_ACC[k.field]
      const set = new Set()
      filtered.forEach((r) => { const v = acc ? acc(r) : r[k.field]; if (v) set.add(v) })
      value = set.size
    }
    return { id: k.id, label: k.label, kind: k.kind, value, delta }
  })
}

/**
 * Responsive layout flags via a ResizeObserver (shadow-DOM-reliable, unlike @container which
 * targets descendants not the container itself). Three steps so the map stays the hero:
 *   <760 single-column + segmented control; <980 slim facet rail; <1180 slim charts/detail rail.
 * Also owns the collapsible table dock (DataTable chevron emits 'toggleTable') and the
 * segmented mobile view switch. Extracted VERBATIM from research-dashboard.vue.
 */
function useResponsiveShell(bus) {
  const shell = ref(null)
  const isNarrow = ref(false)
  const slimRail = ref(false)
  const slimFacet = ref(false)
  const mobileView = ref('map')
  // Getters, for the same reason dashboard.config.js uses them: this array is built before the
  // locale is necessarily known, and a resolved string would freeze the first locale seen.
  const SEG = [
    { k: 'map',    get l() { return tStatic('dashboard.map') || 'Map' } },
    { k: 'facets', get l() { return tStatic('dashboard.filters') || 'Filters' } },
    { k: 'table',  get l() { return tStatic('dashboard.table') || 'Table' } },
    { k: 'charts', get l() { return tStatic('dashboard.charts') || 'Charts' } },
  ]
  let ro = null

  const tableCollapsed = ref(false)
  const facetCollapsed = ref(false)   // left filters rail collapsed → map grows
  const railCollapsed  = ref(false)   // right charts rail collapsed → map grows

  onMounted(() => {
    if (shell.value) {
      ro = new ResizeObserver(() => {
        const w = shell.value.clientWidth
        isNarrow.value = w < 760
        slimRail.value = w >= 760 && w < 1180
        slimFacet.value = w >= 760 && w < 980
      })
      ro.observe(shell.value)
    }
    // collapsible table dock (P5): DataTable's chevron emits 'toggleTable'
    if (bus) bus.on('toggleTable', (v) => { tableCollapsed.value = !!v })
    if (bus) bus.on('toggleFacet', (v) => { facetCollapsed.value = !!v })
    if (bus) bus.on('toggleRail',  (v) => { railCollapsed.value  = !!v })
  })
  onBeforeUnmount(() => ro && ro.disconnect())

  function setView(e) { const el = e.target.closest('[data-view]'); if (el) mobileView.value = el.getAttribute('data-view') }
  const showFacets = computed(() => !isNarrow.value || mobileView.value === 'facets')
  const showMap = computed(() => !isNarrow.value || mobileView.value === 'map')
  const showTable = computed(() => !isNarrow.value || mobileView.value === 'table')
  const showCharts = computed(() => !isNarrow.value || mobileView.value === 'charts')

  return {
    shell, isNarrow, slimRail, slimFacet, mobileView, SEG, tableCollapsed, facetCollapsed, railCollapsed,
    setView, showFacets, showMap, showTable, showCharts,
  }
}

/**
 * Shareable view-state hash URL: serialize filterSet to location.hash; restore on mount.
 *
 * ★ READABLE, CODE-CANONICAL FORMAT (card BUG-SHARE-URL-LEAKS-RAW-CODES). The old hash was
 * URL-encoded JSON -- #f=%7B%22affinity_bloc%22%3A%22A008%22%7D -- unreadable twice over: JSON
 * punctuation percent-escaped, and the value a bare API code. A URL is the one part of the
 * product a user COPIES, PASTES and READS, and for sensitive population data a link you cannot
 * sanity-check before clicking is a real cost. The format is now
 *
 *     #f=affinity_bloc:A008*malay-peoples;religion_family:Hinduism
 *
 * -- the Stack Overflow /questions/123/slug pattern: the CODE is canonical and the *slug is
 * DISPLAY-ONLY, appended from labelFor() at share time and STRIPPED on parse. Restoring never
 * reads the slug, so links stay locale-independent and survive label renames (the card's
 * explicit constraint: keep the code canonical, do not swap in localized labels).
 *
 * `*` is safe as the slug separator because escapeValue() percent-encodes any literal `*` in
 * the VALUE first -- the separator cannot collide with content. `;` and `:` are legal fragment
 * chars, so the whole thing stays legible in the address bar. Legacy JSON hashes (old shared
 * links) are detected by their leading `{` / %7B and still restore.
 */
const slugify = (s) => String(s ?? '').toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/^-+|-+$/g, '').slice(0, 40)
// Minimal escaping, maximal legibility: reserve our three delimiters + %, keep spaces as `+`
// (the x-www-form-urlencoded convention), leave everything else -- including unicode -- alone.
const escapeValue = (s) => String(s).replace(/[%;:*+]/g, (c) => '%' + c.charCodeAt(0).toString(16).toUpperCase()).replace(/ /g, '+')
const unescapeValue = (s) => { try { return decodeURIComponent(String(s).replace(/\+/g, '%20')) } catch (_) { return String(s).replace(/\+/g, ' ') } }

function useHashSync(bus, labelFor) {
  function syncHash() {
    try {
      const pairs = Object.entries(bus.filterSet).map(([k, v]) => {
        const label = typeof labelFor === 'function' ? labelFor(k, v) : null
        const slug = label && String(label) !== String(v) ? slugify(label) : ''
        return k + ':' + escapeValue(v) + (slug ? '*' + slug : '')
      })
      if (typeof location !== 'undefined') history.replaceState(null, '', '#f=' + pairs.join(';'))
    } catch (_) { /* sandboxed */ }
  }
  watch(() => ({ ...bus.filterSet }), syncHash, { deep: true })
  onMounted(() => {
    try {
      const m = typeof location !== 'undefined' && /[#&]f=([^&]+)/.exec(location.hash)
      if (!m) return
      const raw = m[1]
      if (raw.startsWith('{') || raw.startsWith('%7B') || raw.startsWith('%7b')) {
        // legacy JSON hash from an old shared link
        const obj = JSON.parse(decodeURIComponent(raw))
        Object.entries(obj).forEach(([k, v]) => bus.setFilter(k, v))
        return
      }
      for (const pair of raw.split(';')) {
        const i = pair.indexOf(':')
        if (i < 1) continue
        const key = pair.slice(0, i)
        const value = unescapeValue(pair.slice(i + 1).split('*')[0])
        if (key && value) bus.setFilter(key, value)
      }
    } catch (_) { /* ignore bad hash */ }
  })
}

export function useDashboardShell(config) {
  // One brushing-and-linking bus, provided to every panel (publisher + subscriber).
  const bus = createSelectionBus()

  // Teach the bus this profile's facet hierarchy, derived from config.facetRail[].drill, so that
  // clearing a parent facet cascade-clears its descendants on EVERY clear path (tree rail /
  // dropdowns / chip ✕ / Clear All all route through bus.setFilter). Without this, a child
  // predicate outlives its parent and silently ANDs an empty result — see the HIERARCHY CONTRACT
  // in useSelectionBus.js. Configured before any panel can emit a filter.
  bus.configureHierarchy(config)

  // The single in-memory row store — one fetch on mount. (useDashboardData reads the shared
  // @map/config/sources.json activeSource + getApiBaseUrl; config.data may carry overrides.)
  const data = useDashboardData(config.data)

  // THE single former-duplicated FACET_ACC, derived ONCE from config.facets (facetKey -> get).
  const FACET_ACC = mapValues(config.facets, (f) => f.get)

  // Free-text search (header-1 search bar) — ONE shared matcher (buildSearchAccessors +
  // makeSearchMatcher), reused by every panel so the searchable text never drifts.
  const matchSearch = makeSearchMatcher(bus, buildSearchAccessors(config))

  // linked scope: rows surviving every active facet predicate AND the text search (panels fade the rest).
  const filteredRows = computed(() => {
    const rows = data.rows.value || []
    const keys = Object.keys(bus.filterSet)
    const hasText = !!(bus.searchTerm?.value || '').trim()
    if (!keys.length && !hasText) return rows
    const faceted = keys.length
      ? rows.filter((r) => keys.every((k) => { const a = FACET_ACC[k]; return a ? a(r) === bus.filterSet[k] : true }))
      : rows
    // Tiered search over the faceted scope: exact first, fuzzy only if exact finds nothing.
    return filterRowsBySearch(faceted, matchSearch)
  })

  // linked KPI strip — recomputes on every brush.
  const kpis = computed(() => computeKpis(config.kpis, filteredRows.value, data.rows.value || [], FACET_ACC, config))

  // responsive flags + collapsible table dock + segmented mobile view.
  const responsive = useResponsiveShell(bus)

  // ── dataStore adapter (GAP B) — DataSourceManager-normalized (DASH-FIX-2) ──
  // The header's GeocoderComponent bars (DOXA-LIB-3) run useEntitySearch over an
  // injected `dataStore` to surface local people-group / country / language /
  // religion / affinity-bloc / cluster / region suggestions. The MAP profiles get
  // that dataStore from useMapData, which normalizes each raw API row through
  // DataSourceManager — producing the rich feature shape useEntitySearch.buildIndex
  // reads (countryName, affinityBlock[+Label], cluster[+Label], peopleGroup[+Label],
  // wagfRegion/wagfBlock[+Label], religion[+Name], language, _raw).
  //
  // The previous hand-rolled adapter mapped only a few facet accessors, so its
  // features were MISSING the affinity/cluster/PG/region label fields → the
  // geocoder's blocs / clusters / people-groups / families / dialects aggregates
  // never populated and the dashboard dropdown read WORSE than research-map's.
  // FIX: normalize the dashboard's already-loaded raw rows through the SAME
  // DataSourceManager the map uses (reusing the rows we already fetched — no second
  // network request), so useEntitySearch builds an IDENTICAL index and the dropdown
  // results CLONE research-map's. Keyed under the active source id + provided as
  // `searchSourceId` so the bars pass :data-source-id (mirrors research-map's
  // geocoder wiring, GeocoderComponent :data-source-id).
  // Use the SAME source the rows were loaded from (data.sourceId — honors
  // config.data.source, defaults to sourcesConfig.activeSource) so the geocoder's
  // normalization config matches the loaded rows and the bars pass the matching
  // :data-source-id. Never desyncs the row source from the search source.
  const searchSourceId = data.sourceId || sourcesConfig.activeSource
  const searchSourceCfg = sourcesConfig.sources?.[searchSourceId] || {}
  const dsm = new DataSourceManager()
  const geoFeatures = computed(() => {
    const rows = data.rows.value || []
    if (!rows.length) return []
    // normalizeData() consumes AND frees its `rawData` (sets it to null when done);
    // hand it a shallow copy so the dashboard's own row store is never mutated/cleared.
    dsm.rawData = rows.slice()
    dsm.normalizeData(searchSourceCfg)
    return dsm.normalizedData
  })
  // Shape matches what useEntitySearch expects: dataStore.sources[id].features.
  // `features` is a getter over the computed so useEntitySearch's reactive index
  // rebuilds when the rows load.
  const dataStore = { sources: { [searchSourceId]: { get features() { return geoFeatures.value } } } }

  // selection > filter > all CSV exporter (clipboard-primary, sandbox-safe). `dataOpts` carries the
  // profile's source so the exporter's lazy ALL-FIELDS fetch hits the SAME source the rows came from.
  // `labelFor` resolves People CODES to names in the provenance COMMENT line only — constructed
  // here, below `dataStore`, because the resolver reads the normalized features it exposes.
  // Data columns are unaffected (see useCsvExport.buildCsv).
  const { labelFor } = useTreeLegendLabels(config, dataStore, searchSourceId)

  // shareable view-state hash URL -- below labelFor on purpose: the hash's display-only slugs
  // resolve through the SAME code->name resolver the chips and the CSV provenance line use.
  useHashSync(bus, labelFor)
  const exporter = useCsvExport({ rowStore: data.rowStore, rows: data.rows, selectionSet: bus.selectionSet, filterSet: bus.filterSet, FACET_ACC, dataOpts: config.data, labelFor })

  provide('selectionBus', bus)
  provide('dashboardData', data)
  provide('dashboardConfig', config)
  provide('dataStore', dataStore)
  provide('searchSourceId', searchSourceId)

  onMounted(() => data.load())

  return { bus, data, FACET_ACC, filteredRows, kpis, exporter, responsive }
}