#!/usr/bin/env node
import { accessSync } from "node:fs"
import { access, copyFile, mkdir, readFile, writeFile } from "node:fs/promises"
import path from "node:path"
import process from "node:process"
import { fileURLToPath } from "node:url"

const command = process.argv[2]
const args = process.argv.slice(3)
const packageRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..")
const bundledManifestPath = path.join(packageRoot, "manifest.json")
const configFileName = "base-ui-tailwind.json"

main().catch((error) => {
  console.error(error instanceof Error ? error.message : String(error))
  process.exit(1)
})

async function main() {
  if (!command || command === "-h" || command === "--help") {
    printHelp()
    return
  }

  if (command === "init") {
    await initProject(parseOptions(args))
    return
  }

  if (command === "add") {
    await addItems(parseOptions(args))
    return
  }

  throw new Error(`Unknown command: ${command}`)
}

async function initProject(options) {
  const cwd = path.resolve(options.cwd ?? process.cwd())
  const configPath = path.join(cwd, configFileName)
  const localManifestPath = path.join(cwd, "manifest.json")
  const config = {
    manifest: options.manifest ?? ((await exists(localManifestPath)) ? "manifest.json" : bundledManifestPath),
    aliases: {
      ui: "components/ui",
      lib: "lib",
    },
  }

  if (!options.force && (await exists(configPath))) {
    console.log(`${configFileName} already exists. Use --force to overwrite it.`)
    return
  }

  await mkdir(path.join(cwd, config.aliases.ui), { recursive: true })
  await mkdir(path.join(cwd, config.aliases.lib), { recursive: true })
  await writeFile(configPath, `${JSON.stringify(config, null, 2)}\n`)
  console.log(`Created ${path.relative(process.cwd(), configPath) || configFileName}.`)
}

async function addItems(options) {
  const names = options._.filter((item) => !item.startsWith("-"))
  if (names.length === 0) {
    throw new Error("Usage: base-ui-tailwind add <name...>")
  }

  const cwd = path.resolve(options.cwd ?? process.cwd())
  const config = await loadConfig(cwd)
  const manifestRef = options.manifest ?? config.manifest ?? bundledManifestPath
  const manifest = await loadManifest(manifestRef, cwd)
  const selected = resolveItems(manifest, names)
  const files = collectFiles(manifest, selected)
  const written = []
  const skipped = []
  const packageDependencies = collectPackageDependencies(manifest, selected)

  for (const file of files) {
    const targetPath = path.join(cwd, resolveTargetPath(file.target, config.aliases))
    if (!options.overwrite && (await exists(targetPath))) {
      skipped.push(path.relative(cwd, targetPath))
      continue
    }

    if (!options.dryRun) {
      await mkdir(path.dirname(targetPath), { recursive: true })
      const source = await readSourceFile(file.path, manifestRef, cwd)
      if (source.kind === "local") {
        await copyFile(source.path, targetPath)
      } else {
        await writeFile(targetPath, source.contents)
      }
    }

    written.push(path.relative(cwd, targetPath))
  }

  if (written.length > 0) {
    console.log(`${options.dryRun ? "Would add" : "Added"}:`)
    for (const file of written) {
      console.log(`  ${file}`)
    }
  }

  if (skipped.length > 0) {
    console.log("Skipped existing files:")
    for (const file of skipped) {
      console.log(`  ${file}`)
    }
    console.log("Use --overwrite to replace existing files.")
  }

  if (packageDependencies.length > 0) {
    console.log("Required packages:")
    console.log(`  ${packageDependencies.join(" ")}`)
  }
}

function resolveItems(manifest, names) {
  const resolved = new Set()
  const queue = [...names]

  while (queue.length > 0) {
    const name = queue.shift()
    const item = manifest.items?.[name]
    if (!item) {
      throw new Error(`Manifest item not found: ${name}`)
    }
    if (resolved.has(name)) {
      continue
    }

    resolved.add(name)
    for (const dependency of item.localDependencies ?? []) {
      queue.push(dependency)
    }
  }

  return [...resolved]
}

function collectFiles(manifest, names) {
  const files = []
  const seen = new Set()

  for (const name of names) {
    for (const file of manifest.items[name].files ?? []) {
      const key = file.target
      if (!seen.has(key)) {
        seen.add(key)
        files.push(file)
      }
    }
  }

  return files
}

function collectPackageDependencies(manifest, names) {
  const dependencies = new Set()

  for (const name of names) {
    for (const dependency of manifest.items[name].dependencies ?? []) {
      dependencies.add(dependency)
    }
  }

  return [...dependencies].sort((a, b) => a.localeCompare(b))
}

async function loadConfig(cwd) {
  const configPath = path.join(cwd, configFileName)
  if (!(await exists(configPath))) {
    return {
      manifest: undefined,
      aliases: {
        ui: "components/ui",
        lib: "lib",
      },
    }
  }

  const config = JSON.parse(await readFile(configPath, "utf8"))
  return {
    manifest: config.manifest,
    aliases: {
      ui: config.aliases?.ui ?? "components/ui",
      lib: config.aliases?.lib ?? "lib",
    },
  }
}

async function loadManifest(manifestRef, cwd) {
  const contents = isUrl(manifestRef)
    ? await fetchText(manifestRef)
    : await readFile(resolveLocalPath(manifestRef, cwd), "utf8")

  const manifest = JSON.parse(contents)
  if (!manifest.items || typeof manifest.items !== "object") {
    throw new Error("Invalid manifest: missing items.")
  }
  return manifest
}

async function readSourceFile(filePath, manifestRef, cwd) {
  if (isUrl(manifestRef)) {
    return {
      kind: "remote",
      contents: await fetchText(new URL(filePath, manifestRef).toString()),
    }
  }

  return {
    kind: "local",
    path: path.join(path.dirname(resolveLocalPath(manifestRef, cwd)), filePath),
  }
}

function resolveTargetPath(target, aliases) {
  if (target.startsWith("src/components/ui/")) {
    return path.join(aliases.ui, target.slice("src/components/ui/".length))
  }

  if (target.startsWith("src/lib/")) {
    return path.join(aliases.lib, target.slice("src/lib/".length))
  }

  if (target.startsWith("components/ui/")) {
    return path.join(aliases.ui, target.slice("components/ui/".length))
  }

  if (target.startsWith("lib/")) {
    return path.join(aliases.lib, target.slice("lib/".length))
  }

  return target
}

function resolveLocalPath(value, cwd) {
  if (path.isAbsolute(value)) {
    return value
  }

  const projectPath = path.resolve(cwd, value)
  return value === "manifest.json" && !existsSync(projectPath) ? bundledManifestPath : projectPath
}

function parseOptions(values) {
  const options = { _: [] }

  for (let index = 0; index < values.length; index += 1) {
    const value = values[index]

    if (value === "--cwd") {
      options.cwd = values[++index]
    } else if (value === "--manifest") {
      options.manifest = values[++index]
    } else if (value === "--force") {
      options.force = true
    } else if (value === "--overwrite") {
      options.overwrite = true
    } else if (value === "--dry-run") {
      options.dryRun = true
    } else {
      options._.push(value)
    }
  }

  return options
}

async function fetchText(url) {
  const response = await fetch(url)
  if (!response.ok) {
    throw new Error(`Failed to fetch ${url}: ${response.status} ${response.statusText}`)
  }
  return response.text()
}

function existsSync(filePath) {
  try {
    accessSync(filePath)
    return true
  } catch {
    return false
  }
}

async function exists(filePath) {
  try {
    await access(filePath)
    return true
  } catch {
    return false
  }
}

function isUrl(value) {
  return /^https?:\/\//.test(value)
}

function printHelp() {
  console.log(`base-ui-tailwind

Usage:
  base-ui-tailwind init [--manifest <path-or-url>] [--cwd <dir>] [--force]
  base-ui-tailwind add <name...> [--manifest <path-or-url>] [--cwd <dir>] [--overwrite] [--dry-run]
`)
}