#!/usr/bin/env bun

import fs from "node:fs"
import path from "node:path"

const ROOT = path.resolve(import.meta.dir, "..")
const CORE_DIR = path.join(ROOT, "core")

const SCAN_EXTENSIONS = new Set([".md", ".json", ".ts", ".tsx", ".js", ".mjs", ".cjs", ".yaml", ".yml", ".txt"])

export const MOJIBAKE_SIGNATURES: { name: string; pattern: RegExp }[] = [
  { name: "em-dash-mojibake", pattern: /\u9225/ },
  { name: "right-arrow-mojibake", pattern: /\u922B/ },
  { name: "check-mark-mojibake", pattern: /\u9257|\u9253/ },
  { name: "cross-mark-mojibake", pattern: /\u9242/ },
  { name: "geq-mojibake", pattern: /\u922E/ },
  { name: "multiplication-mojibake", pattern: /\u8137/ },
  { name: "replacement-char", pattern: /\uFFFD/ },
  { name: "truncated-mojibake", pattern: /[\u9000-\u9FFF]\?/ },
  { name: "gbk-cjk-bigram", pattern: /椤圭|鍒濆|閰嶇|鐨勶|鎷夎|浼氳瘽|鏃犲|淇濇|缁戝|瀹屾|涓珛|鏀瑰啓|瀹炰緥|鎵归|寤惰|璋冨|绀轰|鍘熸|閰嶉|鎹薄|閫昏|椤甸|绔犵|宸插|鍒嗛|鍏抽|鍚岀|鍚庣|鍓嶇|杩斿|杩涘|閫変|鎸夌|鏉冮|鏂囦|鏂囨/ },
]

export interface EncodingViolation {
  file: string
  line: number
  signature: string
  match: string
}

export function scanFile(filePath: string): EncodingViolation[] {
  const text = fs.readFileSync(filePath, "utf8")
  const violations: EncodingViolation[] = []
  const lines = text.split(/\r?\n/)
  for (let i = 0; i < lines.length; i++) {
    for (const sig of MOJIBAKE_SIGNATURES) {
      const m = lines[i]!.match(sig.pattern)
      if (m) {
        violations.push({
          file: filePath,
          line: i + 1,
          signature: sig.name,
          match: m[0]!,
        })
      }
    }
  }
  return violations
}

export function collectFiles(dir: string): string[] {
  const out: string[] = []
  if (!fs.existsSync(dir)) return out
  const walk = (d: string) => {
    for (const entry of fs.readdirSync(d, { withFileTypes: true })) {
      const full = path.join(d, entry.name)
      if (entry.isDirectory()) walk(full)
      else if (SCAN_EXTENSIONS.has(path.extname(entry.name))) out.push(full)
    }
  }
  walk(dir)
  return out.sort()
}

function main(): void {
  if (!fs.existsSync(CORE_DIR)) {
    console.error(`check-encoding-health: core/ directory not found at ${CORE_DIR} — cannot verify (fail-closed)`)
    process.exit(1)
  }
  const files = collectFiles(CORE_DIR)
  if (files.length === 0) {
    console.error(`check-encoding-health: 0 scannable files under ${CORE_DIR} — cannot verify (fail-closed)`)
    process.exit(1)
  }
  const violations: EncodingViolation[] = []
  for (const f of files) {
    try {
      violations.push(...scanFile(f))
    } catch (err) {
      console.error(`check-encoding-health: failed to read ${f}: ${(err as Error).message}`)
      process.exit(1)
    }
  }
  if (violations.length > 0) {
    console.error(`check-encoding-health: ${violations.length} mojibake violation(s) in core/:`)
    for (const v of violations) {
      const rel = path.relative(ROOT, v.file)
      console.error(`  ${rel}:${v.line} [${v.signature}] ${JSON.stringify(v.match)}`)
    }
    process.exit(1)
  }
  console.log(`check-encoding-health: OK (${files.length} files scanned, 0 violations)`)
}

if (import.meta.main) main()