export type DirectiveToken = {
  type: "if" | "elseif" | "else" | "endif"
  condition?: string
  index: number
  end: number
}

function readCondition(text: string, start: number): { condition: string; end: number } | null {
  let depth = 0
  let inString = false
  let escaped = false

  for (let i = start; i < text.length; i++) {
    const char = text[i]!
    if (escaped) {
      escaped = false
      continue
    }
    if (char === "\\") {
      escaped = true
      continue
    }
    if (char === "\"") {
      inString = !inString
      continue
    }
    if (inString) continue
    if (char === "(") {
      depth += 1
      continue
    }
    if (char === ")") {
      depth -= 1
      if (depth === 0 && text[i + 1] === ">") {
        return { condition: text.slice(start + 1, i), end: i + 2 }
      }
    }
  }

  return null
}

export function getDirectiveTokens(text: string): DirectiveToken[] {
  const tokens: DirectiveToken[] = []
  for (let i = 0; i < text.length; i++) {
    if (text[i] !== "<" || text[i + 1] !== "@") continue
    const rest = text.slice(i + 2)
    const type = ["elseif", "endif", "else", "if"].find(name => rest.startsWith(name)) as DirectiveToken["type"] | undefined
    if (!type) continue
    const afterName = i + 2 + type.length
    if ((type === "if" || type === "elseif") && text[afterName] === "(") {
      const parsed = readCondition(text, afterName)
      if (!parsed) continue
      tokens.push({ type, condition: parsed.condition, index: i, end: parsed.end })
      i = parsed.end - 1
    } else if ((type === "else" || type === "endif") && text[afterName] === ">") {
      tokens.push({ type, index: i, end: afterName + 1 })
      i = afterName
    }
  }
  return tokens
}

export function splitArgs(args: string): string[] {
  const result: string[] = []
  let current = ""
  let depth = 0
  let inString = false
  let escaped = false

  for (const char of args) {
    if (escaped) {
      current += char
      escaped = false
      continue
    }
    if (char === "\\") {
      current += char
      escaped = true
      continue
    }
    if (char === "\"") {
      current += char
      inString = !inString
      continue
    }
    if (!inString && char === "(") depth += 1
    if (!inString && char === ")") depth -= 1
    if (!inString && depth === 0 && char === ",") {
      result.push(current.trim())
      current = ""
      continue
    }
    current += char
  }

  if (current.trim() !== "") result.push(current.trim())
  return result
}