/**
 * Reactive store for the doocus tree browser.
 *
 * Loads the whole-drive tree from /api/tree (index.json), builds a folder
 * hierarchy from the flat file list, lazily fetches per-file detail on select,
 * and tracks the packaging selection. Read-only over the pipeline output.
 */
import { reactive, computed } from 'vue'

export interface FileNode {
  path: string
  name: string
  ext: string
  family: string
  mode: 'extracted' | 'meeting' | 'link'
  bytes: number
  modified: string
  url: string | null
  out?: string
  words?: number
  title?: string
  warnings?: string[]
}

export interface Detail {
  node: FileNode
  content: string | null   // extracted search text (heavy formats), markdown
  meta: Record<string, unknown> | null
  text: string | null      // inline text for text-native originals
  mime: string
  originalUrl: string
}

/** A folder or file in the display tree. */
export interface TreeItem {
  name: string
  path: string
  dir: boolean
  children?: TreeItem[]
  node?: FileNode
}

export interface Target {
  key: string
  label: string
  maxFiles: number
  maxBytes: number
}

export const TARGETS: Target[] = [
  { key: 'gemini', label: 'Gemini web', maxFiles: 10, maxBytes: 100 * 1024 * 1024 },
  { key: 'notebooklm', label: 'NotebookLM', maxFiles: 50, maxBytes: 200 * 1024 * 1024 },
]

interface State {
  root: string
  files: FileNode[]
  tree: TreeItem[]
  counts: Record<string, number>
  selectedPath: string | null
  detail: Detail | null
  loading: boolean
  selected: Set<string>
  collapsed: Set<string>   // collapsed folder paths (folders default open)
  detailCollapsed: boolean // bottom viewer collapsed to a bar
  targetKey: string
  error: string
}

export const store = reactive<State>({
  root: '',
  files: [],
  tree: [],
  counts: {},
  selectedPath: null,
  detail: null,
  loading: false,
  selected: new Set<string>(),
  collapsed: new Set<string>(),
  detailCollapsed: false,
  targetKey: TARGETS[0].key,
  error: '',
})

export function toggleFolder(path: string): void {
  if (store.collapsed.has(path)) store.collapsed.delete(path)
  else store.collapsed.add(path)
}

/** Build a nested folder tree from flat posix paths, folders before files. */
function buildTree(files: FileNode[]): TreeItem[] {
  const root: TreeItem = { name: '', path: '', dir: true, children: [] }
  for (const f of files) {
    const parts = f.path.split('/')
    let cur = root
    for (let i = 0; i < parts.length - 1; i++) {
      const seg = parts[i]
      const p = parts.slice(0, i + 1).join('/')
      let next = cur.children!.find((c) => c.dir && c.name === seg)
      if (!next) {
        next = { name: seg, path: p, dir: true, children: [] }
        cur.children!.push(next)
      }
      cur = next
    }
    cur.children!.push({ name: f.name, path: f.path, dir: false, node: f })
  }
  const sort = (items: TreeItem[]): TreeItem[] => {
    items.sort((a, b) =>
      a.dir === b.dir ? a.name.localeCompare(b.name) : a.dir ? -1 : 1)
    for (const it of items) if (it.dir) sort(it.children!)
    return items
  }
  return sort(root.children!)
}

export async function loadTree(): Promise<void> {
  store.loading = true
  store.error = ''
  try {
    const res = await fetch('/api/tree')
    if (!res.ok) { store.error = (await res.json()).error ?? `HTTP ${res.status}`; return }
    const index = await res.json()
    store.root = index.root
    store.files = index.files
    store.counts = index.counts
    store.tree = buildTree(index.files)
  } catch (e) {
    store.error = String(e)
  } finally {
    store.loading = false
  }
}

export async function select(path: string): Promise<void> {
  store.selectedPath = path
  store.detail = null
  const res = await fetch(`/api/detail?path=${encodeURIComponent(path)}`)
  if (res.ok) store.detail = await res.json()
}

export function toggleSelect(path: string): void {
  if (store.selected.has(path)) store.selected.delete(path)
  else store.selected.add(path)
}

export const target = computed(() => TARGETS.find((t) => t.key === store.targetKey) ?? TARGETS[0])

/** Package estimate: one original per selected file (+ a small sidecar for extracted). */
export const packageEstimate = computed(() => {
  const chosen = store.files.filter((f) => store.selected.has(f.path))
  let files = 0
  let bytes = 0
  for (const f of chosen) {
    files += 1                                   // the original
    bytes += f.bytes
    if (f.mode === 'extracted') { files += 1; bytes += (f.words ?? 0) * 6 + 512 }  // content.md
  }
  const t = target.value
  return { docCount: chosen.length, files, bytes, overFiles: files > t.maxFiles, overBytes: bytes > t.maxBytes }
})

export function humanBytes(n: number): string {
  if (n < 1024) return `${n} B`
  if (n < 1024 * 1024) return `${(n / 1024).toFixed(1)} KB`
  return `${(n / 1024 / 1024).toFixed(1)} MB`
}

export type ViewerKind =
  | 'pdf' | 'image' | 'html' | 'markdown' | 'code' | 'docx' | 'xlsx' | 'pptx' | 'video' | 'unhandled'

/** Single source of truth for how a file is viewed — shared by the tree (to flag
 *  unhandled types) and the viewer. 'unhandled' = no inline view; default action
 *  is to open the original file (or the Drive link once we have it). */
export function kindFor(ext: string): ViewerKind {
  if (ext === 'pdf') return 'pdf'
  if (['png', 'jpg', 'jpeg', 'gif', 'webp', 'svg'].includes(ext)) return 'image'
  if (['html', 'htm'].includes(ext)) return 'html'
  if (['md', 'markdown'].includes(ext)) return 'markdown'
  if (['txt', 'json', 'yaml', 'yml', 'csv', 'log', 'ini', 'xml', 'toml'].includes(ext)) return 'code'
  if (ext === 'docx') return 'docx'
  if (ext === 'xlsx') return 'xlsx'
  if (ext === 'pptx') return 'pptx'
  if (['mp4', 'mkv', 'mov', 'm4v', 'webm', 'avi', 'wmv'].includes(ext)) return 'video'
  return 'unhandled'
}

export function isUnhandled(node: FileNode): boolean {
  return node.mode !== 'meeting' && kindFor(node.ext) === 'unhandled'
}