import type { D3roSupabaseClient, HistoryEntry } from '@d3ro/api-client'

export type HistoryListFilter = 'all' | 'favorites'

export interface HistoryCursor {
  createdAt: string
  id: string
}

export interface HistoryPageOptions {
  userId: string
  filter: HistoryListFilter
  search: string
  pageSize: number
  cursor: HistoryCursor | null
}

export interface HistoryPageResult {
  entries: HistoryEntry[]
  nextCursor: HistoryCursor | null
}

export type HistoryClientErrorCode = 'auth' | 'conflict' | 'not-found' | 'validation' | 'network' | 'server'

export class HistoryClientError extends Error {
  constructor(
    public readonly code: HistoryClientErrorCode,
    message: string
  ) {
    super(message)
    this.name = 'HistoryClientError'
  }
}

export interface HistoryUpdate {
  title?: string | null
  original_text?: string
  polished_text?: string | null
  is_favorite?: boolean
}

const MAX_PAGE_SIZE = 50
const UUID_PATTERN = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i

function requireUuid(value: string, code: 'auth' | 'validation', message: string): void {
  if (!UUID_PATTERN.test(value)) throw new HistoryClientError(code, message)
}

function mapError(error: unknown): HistoryClientError {
  if (error instanceof HistoryClientError) return error

  const candidate = error as { code?: unknown; message?: unknown }
  const databaseCode = typeof candidate?.code === 'string' ? candidate.code : ''
  const message = typeof candidate?.message === 'string' ? candidate.message : 'History request failed'
  const normalized = message.toLowerCase()

  if (
    error instanceof TypeError
    || normalized.includes('failed to fetch')
    || normalized.includes('network request failed')
    || normalized.includes('networkerror')
  ) {
    return new HistoryClientError('network', message)
  }
  if (databaseCode === 'PGRST301' || databaseCode === '42501' || normalized.includes('jwt')) {
    return new HistoryClientError('auth', message)
  }
  return new HistoryClientError('server', message)
}

export function sanitizeHistorySearch(value: string): string {
  return value
    .trim()
    .slice(0, 100)
    .replace(/[%,()._'"\\]/g, ' ')
    .replace(/\s+/g, ' ')
    .trim()
}

export async function listHistoryPage(
  client: D3roSupabaseClient,
  options: HistoryPageOptions
): Promise<HistoryPageResult> {
  requireUuid(options.userId, 'auth', 'A valid authenticated user is required')
  const pageSize = Math.max(1, Math.min(options.pageSize, MAX_PAGE_SIZE))

  try {
    let query = client
      .from('history')
      .select('*')
      .eq('user_id', options.userId)
      .order('created_at', { ascending: false })
      .order('id', { ascending: false })
      .limit(pageSize + 1)

    if (options.filter === 'favorites') query = query.eq('is_favorite', true)
    if (options.cursor !== null) {
      query = query.or(
        `created_at.lt.${options.cursor.createdAt},and(created_at.eq.${options.cursor.createdAt},id.lt.${options.cursor.id})`
      )
    }

    const search = sanitizeHistorySearch(options.search)
    if (search.length > 0) {
      const pattern = `%${search}%`
      query = query.or(
        `title.ilike.${pattern},original_text.ilike.${pattern},polished_text.ilike.${pattern},summary_text.ilike.${pattern}`
      )
    }

    const { data, error } = await query
    if (error) throw error

    const rows = data ?? []
    const hasMore = rows.length > pageSize
    const entries = hasMore ? rows.slice(0, pageSize) : rows
    const last = entries.at(-1)
    return {
      entries,
      nextCursor: hasMore && last ? { createdAt: last.created_at, id: last.id } : null
    }
  } catch (error) {
    throw mapError(error)
  }
}

export async function getHistoryEntry(
  client: D3roSupabaseClient,
  userId: string,
  entryId: string
): Promise<HistoryEntry> {
  requireUuid(userId, 'auth', 'A valid authenticated user is required')
  requireUuid(entryId, 'validation', 'A valid history id is required')

  try {
    const { data, error } = await client
      .from('history')
      .select('*')
      .eq('user_id', userId)
      .eq('id', entryId)
      .maybeSingle()

    if (error) throw error
    if (!data) throw new HistoryClientError('not-found', 'History entry was not found')
    return data
  } catch (error) {
    throw mapError(error)
  }
}

export async function updateHistoryEntryRevisionSafe(
  client: D3roSupabaseClient,
  userId: string,
  entryId: string,
  expectedRevision: number,
  patch: HistoryUpdate
): Promise<HistoryEntry> {
  requireUuid(userId, 'auth', 'A valid authenticated user is required')
  requireUuid(entryId, 'validation', 'A valid history id is required')
  if (!Number.isSafeInteger(expectedRevision) || expectedRevision < 1) {
    throw new HistoryClientError('validation', 'Expected revision is invalid')
  }
  if (Object.keys(patch).length === 0) {
    throw new HistoryClientError('validation', 'At least one field is required')
  }

  try {
    const { data, error } = await client
      .from('history')
      .update({ ...patch, revision: expectedRevision + 1 })
      .eq('user_id', userId)
      .eq('id', entryId)
      .eq('revision', expectedRevision)
      .select('*')
      .maybeSingle()

    if (error) throw error
    if (!data) throw new HistoryClientError('conflict', 'History revision changed')
    return data
  } catch (error) {
    throw mapError(error)
  }
}

export async function deleteHistoryEntryRevisionSafe(
  client: D3roSupabaseClient,
  userId: string,
  entryId: string,
  expectedRevision: number
): Promise<void> {
  requireUuid(userId, 'auth', 'A valid authenticated user is required')
  requireUuid(entryId, 'validation', 'A valid history id is required')
  if (!Number.isSafeInteger(expectedRevision) || expectedRevision < 1) {
    throw new HistoryClientError('validation', 'Expected revision is invalid')
  }

  try {
    const { data, error } = await client
      .from('history')
      .delete()
      .eq('user_id', userId)
      .eq('id', entryId)
      .eq('revision', expectedRevision)
      .select('id')
      .maybeSingle()

    if (error) throw error
    if (!data) throw new HistoryClientError('conflict', 'History revision changed')
  } catch (error) {
    throw mapError(error)
  }
}