import { existsSync } from 'node:fs'
import { fileURLToPath } from 'node:url'
import { DEFAULT_MAX_INSPECT_TARGETS } from '../shared/workspace-observation.js'
import type { HostPluginContext } from './contracts.js'
import { ideGateway } from './gateway.js'
import { DEFAULT_SEARCH_LIMITS } from './search.js'
import { workspaceSearchProvider } from './search-provider.js'
import { resolveTerminalShell } from './terminal.js'
import { terminalProvider } from './terminal-provider.js'
import { workspaceFilesProvider } from './workspace-files-provider.js'
import { workspaceMutationsGateway } from './workspace-mutations-gateway.js'
import { workspaceMutationsProvider } from './workspace-mutations-provider.js'
import { workspaceMutationBackendProvider } from './mutation-backend-provider.js'
import { workspaceResourcesProvider } from './workspace-resources-provider.js'

export interface Config {
  staticRoot?: string
  maxFileBytes?: number
  maxMediaBytes?: number
  maxRequestBytes?: number
  maxDirectoryEntries?: number
  maxInspectTargets?: number
  maxInspectDirectoryEntries?: number
  terminalShell?: string
  terminalArgs?: string[]
  maxTerminalSessions?: number
  maxTerminalMessageBytes?: number
  maxTerminalInputBytes?: number
  maxTerminalBufferedBytes?: number
  maxSearchFileResults?: number
  maxSearchTextResults?: number
  maxSearchCandidates?: number
  maxSearchRawBytes?: number
  maxSearchPreviewBytes?: number
  maxSearchQueryBytes?: number
  maxSearchLineBytes?: number
  maxSearchResponseBytes?: number
  maxConcurrentSearches?: number
  searchTimeoutMs?: number
  searchTerminationGraceMs?: number
  maxQueuedMutations?: number
  mutationReceiptTtlMs?: number
  maxMutationReceipts?: number
  maxMutationOperationIds?: number
  maxMutationPurgeJobs?: number
  maxMutationPurgeEntries?: number
  maxMutationRequestBytes?: number
}

export interface ResolvedConfig {
  routePrefix: string
  staticRoot: string
  maxFileBytes: number
  maxMediaBytes: number
  maxRequestBytes: number
  maxDirectoryEntries: number
  maxInspectTargets: number
  maxInspectDirectoryEntries: number
  terminalShell: string
  terminalArgs: string[]
  maxTerminalSessions: number
  maxTerminalMessageBytes: number
  maxTerminalInputBytes: number
  maxTerminalBufferedBytes: number
  maxSearchFileResults: number
  maxSearchTextResults: number
  maxSearchCandidates: number
  maxSearchRawBytes: number
  maxSearchPreviewBytes: number
  maxSearchQueryBytes: number
  maxSearchLineBytes: number
  maxSearchResponseBytes: number
  maxConcurrentSearches: number
  searchTimeoutMs: number
  searchTerminationGraceMs: number
  maxQueuedMutations: number
  mutationReceiptTtlMs: number
  maxMutationReceipts: number
  maxMutationOperationIds: number
  maxMutationPurgeJobs: number
  maxMutationPurgeEntries: number
  maxMutationRequestBytes: number
}

function positiveInteger(value: number | undefined, fallback: number, name: string, maximum: number): number {
  const resolved = value ?? fallback
  if (!Number.isSafeInteger(resolved) || resolved <= 0 || resolved > maximum) {
    throw new Error(`dsh-code-ide: ${name} must be a positive integer no greater than ${String(maximum)}`)
  }
  return resolved
}

function defaultStaticRoot(): string {
  const compiled = fileURLToPath(new URL('../../client/', import.meta.url))
  if (existsSync(compiled)) return compiled
  return fileURLToPath(new URL('../../dist/client/', import.meta.url))
}

/** Resolve and validate Host limits before any child component is registered. */
export function resolveConfig(config: Config): ResolvedConfig {
  const routePrefix = '/dsh-code-ide'
  const maxFileBytes = positiveInteger(config.maxFileBytes, 4 * 1024 * 1024, 'maxFileBytes', 64 * 1024 * 1024)
  const maxDirectoryEntries = positiveInteger(config.maxDirectoryEntries, 5_000, 'maxDirectoryEntries', 100_000)
  const terminal = resolveTerminalShell(config.terminalShell)
  return {
    routePrefix,
    staticRoot: config.staticRoot ?? defaultStaticRoot(),
    maxFileBytes,
    maxMediaBytes: positiveInteger(
      config.maxMediaBytes,
      512 * 1024 * 1024,
      'maxMediaBytes',
      8 * 1024 * 1024 * 1024,
    ),
    maxRequestBytes: positiveInteger(
      config.maxRequestBytes,
      maxFileBytes * 6 + 64 * 1024,
      'maxRequestBytes',
      64 * 1024 * 1024 * 6 + 64 * 1024,
    ),
    maxDirectoryEntries,
    maxInspectTargets: positiveInteger(
      config.maxInspectTargets,
      DEFAULT_MAX_INSPECT_TARGETS,
      'maxInspectTargets',
      4_096,
    ),
    maxInspectDirectoryEntries: positiveInteger(
      config.maxInspectDirectoryEntries,
      maxDirectoryEntries,
      'maxInspectDirectoryEntries',
      100_000,
    ),
    terminalShell: terminal.shell,
    terminalArgs: config.terminalArgs ?? terminal.args,
    maxTerminalSessions: positiveInteger(config.maxTerminalSessions, 8, 'maxTerminalSessions', 64),
    maxTerminalMessageBytes: positiveInteger(config.maxTerminalMessageBytes, 256 * 1024, 'maxTerminalMessageBytes', 4 * 1024 * 1024),
    maxTerminalInputBytes: positiveInteger(config.maxTerminalInputBytes, 64 * 1024, 'maxTerminalInputBytes', 1024 * 1024),
    maxTerminalBufferedBytes: positiveInteger(config.maxTerminalBufferedBytes, 4 * 1024 * 1024, 'maxTerminalBufferedBytes', 64 * 1024 * 1024),
    maxSearchFileResults: positiveInteger(config.maxSearchFileResults, DEFAULT_SEARCH_LIMITS.maxFileResults, 'maxSearchFileResults', 10_000),
    maxSearchTextResults: positiveInteger(config.maxSearchTextResults, DEFAULT_SEARCH_LIMITS.maxTextResults, 'maxSearchTextResults', 100_000),
    maxSearchCandidates: positiveInteger(config.maxSearchCandidates, DEFAULT_SEARCH_LIMITS.maxCandidates, 'maxSearchCandidates', 1_000_000),
    maxSearchRawBytes: positiveInteger(config.maxSearchRawBytes, DEFAULT_SEARCH_LIMITS.maxRawBytes, 'maxSearchRawBytes', 64 * 1024 * 1024),
    maxSearchPreviewBytes: positiveInteger(config.maxSearchPreviewBytes, DEFAULT_SEARCH_LIMITS.maxPreviewBytes, 'maxSearchPreviewBytes', 64 * 1024),
    maxSearchQueryBytes: positiveInteger(config.maxSearchQueryBytes, DEFAULT_SEARCH_LIMITS.maxQueryBytes, 'maxSearchQueryBytes', 64 * 1024),
    maxSearchLineBytes: positiveInteger(config.maxSearchLineBytes, DEFAULT_SEARCH_LIMITS.maxLineBytes, 'maxSearchLineBytes', 16 * 1024 * 1024),
    maxSearchResponseBytes: positiveInteger(config.maxSearchResponseBytes, DEFAULT_SEARCH_LIMITS.maxResponseBytes, 'maxSearchResponseBytes', 64 * 1024 * 1024),
    maxConcurrentSearches: positiveInteger(config.maxConcurrentSearches, DEFAULT_SEARCH_LIMITS.maxConcurrent, 'maxConcurrentSearches', 32),
    searchTimeoutMs: positiveInteger(config.searchTimeoutMs, DEFAULT_SEARCH_LIMITS.timeoutMs, 'searchTimeoutMs', 10 * 60 * 1_000),
    searchTerminationGraceMs: positiveInteger(config.searchTerminationGraceMs, DEFAULT_SEARCH_LIMITS.terminationGraceMs, 'searchTerminationGraceMs', 30_000),
    maxQueuedMutations: positiveInteger(config.maxQueuedMutations, 64, 'maxQueuedMutations', 4_096),
    mutationReceiptTtlMs: positiveInteger(config.mutationReceiptTtlMs, 5 * 60_000, 'mutationReceiptTtlMs', 24 * 60 * 60_000),
    maxMutationReceipts: positiveInteger(config.maxMutationReceipts, 1_024, 'maxMutationReceipts', 65_536),
    maxMutationOperationIds: positiveInteger(config.maxMutationOperationIds, 65_536, 'maxMutationOperationIds', 262_144),
    maxMutationPurgeJobs: positiveInteger(config.maxMutationPurgeJobs, 1_024, 'maxMutationPurgeJobs', 65_536),
    maxMutationPurgeEntries: positiveInteger(config.maxMutationPurgeEntries, 100_000, 'maxMutationPurgeEntries', 1_000_000),
    maxMutationRequestBytes: positiveInteger(config.maxMutationRequestBytes, 64 * 1024, 'maxMutationRequestBytes', 256 * 1024),
  }
}

/** Stable Cordis plugin name. */
export const name = 'dsh-code-ide'

/** Root orchestration deliberately owns no Host services or routes itself. */
export const inject: string[] = []

/** Compose independently reloadable providers with their route-owning gateway. */
export function apply(ctx: HostPluginContext, input: Config = {}): void {
  const config = resolveConfig(input)
  ctx.plugin(workspaceResourcesProvider, {
    maxQueuedMutations: config.maxQueuedMutations,
  })
  ctx.plugin(workspaceMutationBackendProvider, {})
  ctx.plugin(workspaceFilesProvider, {
    maxFileBytes: config.maxFileBytes,
    maxMediaBytes: config.maxMediaBytes,
    maxDirectoryEntries: config.maxDirectoryEntries,
    maxInspectTargets: config.maxInspectTargets,
    maxInspectDirectoryEntries: config.maxInspectDirectoryEntries,
  })
  ctx.plugin(workspaceMutationsProvider, {
    receiptTtlMs: config.mutationReceiptTtlMs,
    maxReceipts: config.maxMutationReceipts,
    maxOperationIds: config.maxMutationOperationIds,
    maxPurgeJobs: config.maxMutationPurgeJobs,
    maxPurgeEntries: config.maxMutationPurgeEntries,
  })
  ctx.plugin(terminalProvider, {
    terminalShell: config.terminalShell,
    terminalArgs: config.terminalArgs,
    maxTerminalSessions: config.maxTerminalSessions,
    maxTerminalMessageBytes: config.maxTerminalMessageBytes,
    maxTerminalInputBytes: config.maxTerminalInputBytes,
    maxTerminalBufferedBytes: config.maxTerminalBufferedBytes,
  })
  ctx.plugin(workspaceSearchProvider, {
    maxFileBytes: config.maxFileBytes,
    maxFileResults: config.maxSearchFileResults,
    maxTextResults: config.maxSearchTextResults,
    maxCandidates: config.maxSearchCandidates,
    maxRawBytes: config.maxSearchRawBytes,
    maxPreviewBytes: config.maxSearchPreviewBytes,
    maxQueryBytes: config.maxSearchQueryBytes,
    maxLineBytes: config.maxSearchLineBytes,
    maxResponseBytes: config.maxSearchResponseBytes,
    maxConcurrent: config.maxConcurrentSearches,
    timeoutMs: config.searchTimeoutMs,
    terminationGraceMs: config.searchTerminationGraceMs,
  })
  ctx.plugin(ideGateway, {
    routePrefix: config.routePrefix,
    staticRoot: config.staticRoot,
    maxRequestBytes: config.maxRequestBytes,
    maxTerminalSessions: config.maxTerminalSessions,
  })
  ctx.plugin(workspaceMutationsGateway, {
    maxRequestBytes: config.maxMutationRequestBytes,
  })
}