import z from "zod/v4"

import * as fs from "fs"

import * as path from "path"

import { Tool } from "./tool"

import { LSP } from "../lsp"

import { FileTime } from "../file/time"

import DESCRIPTION from "./read.txt"

import { Filesystem } from "../util/filesystem"

import { Instance } from "../project/instance"

const DEFAULT_READ_LIMIT = 2000

const MAX_LINE_LENGTH = 2000

export const ReadTool = Tool.define("read", {

description: DESCRIPTION,

parameters: z.object({

filePath: z.string().describe("The path to the file to read"),

offset: z.coerce.number().describe("The line number to start reading from (0-based)").optional(),

limit: z.coerce.number().describe("The number of lines to read (defaults to 2000)").optional(),

}),

async execute(params, ctx) {

let filepath = params.filePath

if (!path.isAbsolute(filepath)) {

filepath = path.join(process.cwd(), filepath)

}

if (!ctx.extra?.["bypassCwdCheck"] && !Filesystem.contains(Instance.directory, filepath)) {

throw new Error(`File ${filepath} is not in the current working directory`)

}

const file = Bun.file(filepath)

if (!(await file.exists())) {

const dir = path.dirname(filepath)

const base = path.basename(filepath)

const dirEntries = fs.readdirSync(dir)

const suggestions = dirEntries

.filter(

(entry) =>

entry.toLowerCase().includes(base.toLowerCase()) || base.toLowerCase().includes(entry.toLowerCase()),

)

.map((entry) => path.join(dir, entry))

.slice(0, 3)

if (suggestions.length > 0) {

throw new Error(`File not found: ${filepath}\n\nDid you mean one of these?\n${suggestions.join("\n")}`)

}

throw new Error(`File not found: ${filepath}`)

}

const limit = params.limit ?? DEFAULT_READ_LIMIT

const offset = params.offset || 0

const isImage = isImageFile(filepath)

if (isImage) throw new Error(`This is an image file of type: ${isImage}\nUse a different tool to process images`)

const isBinary = await isBinaryFile(filepath, file)

if (isBinary) throw new Error(`Cannot read binary file: ${filepath}`)

const lines = await file.text().then((text) => text.split("\n"))

const raw = lines.slice(offset, offset + limit).map((line) => {

return line.length > MAX_LINE_LENGTH ? line.substring(0, MAX_LINE_LENGTH) + "..." : line

})

const content = raw.map((line, index) => {

return `${(index + offset + 1).toString().padStart(5, "0")}| ${line}`

})

const preview = raw.slice(0, 20).join("\n")

let output = "<file>\n"

output += content.join("\n")

if (lines.length > offset + content.length) {

output += `\n\n(File has more lines. Use 'offset' parameter to read beyond line ${offset + content.length})`

}

output += "\n</file>"

// just warms the lsp client

LSP.touchFile(filepath, false)

FileTime.read(ctx.sessionID, filepath)

return {

title: path.relative(Instance.worktree, filepath),

output,

metadata: {

preview,

},

}

},

})

function isImageFile(filePath: string): string | false {

const ext = path.extname(filePath).toLowerCase()

switch (ext) {

case ".jpg":

case ".jpeg":

return "JPEG"

case ".png":

return "PNG"

case ".gif":

return "GIF"

case ".bmp":

return "BMP"

case ".webp":

return "WebP"

default:

return false

}

}

async function isBinaryFile(filepath: string, file: Bun.BunFile): Promise<boolean> {

const ext = path.extname(filepath).toLowerCase()

// binary check for common non-text extensions

switch (ext) {

case ".zip":

case ".tar":

case ".gz":

case ".exe":

case ".dll":

case ".so":

case ".class":

case ".jar":

case ".war":

case ".7z":

case ".doc":

case ".docx":

case ".xls":

case ".xlsx":

case ".ppt":

case ".pptx":

case ".odt":

case ".ods":

case ".odp":

case ".bin":

case ".dat":

case ".obj":

case ".o":

case ".a":

case ".lib":

case ".wasm":

case ".pyc":

case ".pyo":

return true

default:

break

}

const stat = await file.stat()

const fileSize = stat.size

if (fileSize === 0) return false

const bufferSize = Math.min(4096, fileSize)

const buffer = await file.arrayBuffer()

if (buffer.byteLength === 0) return false

const bytes = new Uint8Array(buffer.slice(0, bufferSize))

let nonPrintableCount = 0

for (let i = 0; i < bytes.length; i++) {

if (bytes[i] === 0) return true

if (bytes[i] < 9 || (bytes[i] > 13 && bytes[i] < 32)) {

nonPrintableCount++

}

}

// If >30% non-printable characters, consider it binary

return nonPrintableCount / bytes.length > 0.3

}