import z from "zod"
import os from "os"
import { createWriteStream } from "node:fs"
import * as Tool from "./tool"
import path from "path"
import DESCRIPTION from "./bash.txt"
import { Log } from "../util"
import { Instance } from "../project/instance"
import { lazy } from "@/util/lazy"
import { Language, type Node } from "web-tree-sitter"

import { AppFileSystem } from "@opencode-ai/shared/filesystem"
import { fileURLToPath } from "url"
import { Flag } from "@/flag/flag"
import { Shell } from "@/shell/shell"

import { BashArity } from "@/permission/arity"
import * as Truncate from "./truncate"
import { Plugin } from "@/plugin"
import { Effect, Stream } from "effect"
import { ChildProcess } from "effect/unstable/process"
import { ChildProcessSpawner } from "effect/unstable/process/ChildProcessSpawner"

const MAX_METADATA_LENGTH = 30_000
const DEFAULT_TIMEOUT = Flag.OPENCODE_EXPERIMENTAL_BASH_DEFAULT_TIMEOUT_MS || 2 * 60 * 1000
const PS = new Set(["powershell", "pwsh"])
const CWD = new Set(["cd", "push-location", "set-location"])
const FILES = new Set([
  ...CWD,
  "rm",
  "cp",
  "mv",
  "mkdir",
  "touch",
  "chmod",
  "chown",
  "cat",
  // Leave PowerShell aliases out for now. Common ones like cat/cp/mv/rm/mkdir
  // already hit the entries above, and alias normalization should happen in one
  // place later so we do not risk double-prompting.
  "get-content",
  "set-content",
  "add-content",
  "copy-item",
  "move-item",
  "remove-item",
  "new-item",
  "rename-item",
])
const FLAGS = new Set(["-destination", "-literalpath", "-path"])
const SWITCHES = new Set(["-confirm", "-debug", "-force", "-nonewline", "-recurse", "-verbose", "-whatif"])

const Parameters = z.object({
  command: z.string().describe("The command to execute"),
  timeout: z.number().describe("Optional timeout in milliseconds").optional(),
  workdir: z
    .string()
    .describe(
      `The working directory to run the command in. Defaults to the current directory. Use this instead of 'cd' commands.`,
    )
    .optional(),
  description: z
    .string()
    .describe(
      "Clear, concise description of what this command does in 5-10 words. Examples:\nInput: ls\nOutput: Lists files in current directory\n\nInput: git status\nOutput: Shows working tree status\n\nInput: npm install\nOutput: Installs package dependencies\n\nInput: mkdir foo\nOutput: Creates directory 'foo'",
    ),
})

type Part = {
  type: string
  text: string
}

type Scan = {
  dirs: Set<string>
  patterns: Set<string>
  always: Set<string>
}

type Chunk = {
  text: string
  size: number
}

export const log = Log.create({ service: "bash-tool" })

const resolveWasm = (asset: string) => {
  if (asset.startsWith("file://")) return fileURLToPath(asset)
  if (asset.startsWith("/") || /^[a-z]:/i.test(asset)) return asset
  const url = new URL(asset, import.meta.url)
  return fileURLToPath(url)
}

function parts(node: Node) {
  const out: Part[] = []
  for (let i = 0; i < node.childCount; i++) {
    const child = node.child(i)
    if (!child) continue
    if (child.type === "command_elements") {
      for (let j = 0; j < child.childCount; j++) {
        const item = child.child(j)
        if (!item || item.type === "command_argument_sep" || item.type === "redirection") continue
        out.push({ type: item.type, text: item.text })
      }
      continue
    }
    if (
      child.type !== "command_name" &&
      child.type !== "command_name_expr" &&
      child.type !== "word" &&
      child.type !== "string" &&
      child.type !== "raw_string" &&
      child.type !== "concatenation"
    ) {
      continue
    }
    out.push({ type: child.type, text: child.text })
  }
  return out
}

function source(node: Node) {
  return (node.parent?.type === "redirected_statement" ? node.parent.text : node.text).trim()
}

function commands(node: Node) {
  return node.descendantsOfType("command").filter((child): child is Node => Boolean(child))
}

function unquote(text: string) {
  if (text.length < 2) return text
  const first = text[0]
  const last = text[text.length - 1]
  if ((first === '"' || first === "'") && first === last) return text.slice(1, -1)
  return text
}

function home(text: string) {
  if (text === "~") return os.homedir()
  if (text.startsWith("~/") || text.startsWith("~\\")) return path.join(os.homedir(), text.slice(2))
  return text
}

function envValue(key: string) {
  if (process.platform !== "win32") return process.env[key]
  const name = Object.keys(process.env).find((item) => item.toLowerCase() === key.toLowerCase())
  return name ? process.env[name] : undefined
}

function auto(key: string, cwd: string, shell: string) {
  const name = key.toUpperCase()
  if (name === "HOME") return os.homedir()
  if (name === "PWD") return cwd
  if (name === "PSHOME") return path.dirname(shell)
}

function expand(text: string, cwd: string, shell: string) {
  const out = unquote(text)
    .replace(/\$\{env:([^}]+)\}/gi, (_, key: string) => envValue(key) || "")
    .replace(/\$env:([A-Za-z_][A-Za-z0-9_]*)/gi, (_, key: string) => envValue(key) || "")
    .replace(/\$(HOME|PWD|PSHOME)(?=$|[\\/])/gi, (_, key: string) => auto(key, cwd, shell) || "")
  return home(out)
}

function provider(text: string) {
  const match = text.match(/^([A-Za-z]+)::(.*)$/)
  if (match) {
    if (match[1].toLowerCase() !== "filesystem") return
    return match[2]
  }
  const prefix = text.match(/^([A-Za-z]+):(.*)$/)
  if (!prefix) return text
  if (prefix[1].length === 1) return text
  return
}

function dynamic(text: string, ps: boolean) {
  if (text.startsWith("(") || text.startsWith("@(")) return true
  if (text.includes("$(") || text.includes("${") || text.includes("`")) return true
  if (ps) return /\$(?!env:)/i.test(text)
  return text.includes("$")
}

function prefix(text: string) {
  const match = /[?*[]/.exec(text)
  if (!match) return text
  if (match.index === 0) return
  return text.slice(0, match.index)
}

function pathArgs(list: Part[], ps: boolean) {
  if (!ps) {
    return list
      .slice(1)
      .filter((item) => !item.text.startsWith("-") && !(list[0]?.text === "chmod" && item.text.startsWith("+")))
      .map((item) => item.text)
  }

  const out: string[] = []
  let want = false
  for (const item of list.slice(1)) {
    if (want) {
      out.push(item.text)
      want = false
      continue
    }
    if (item.type === "command_parameter") {
      const flag = item.text.toLowerCase()
      if (SWITCHES.has(flag)) continue
      want = FLAGS.has(flag)
      continue
    }
    out.push(item.text)
  }
  return out
}

function preview(text: string) {
  if (text.length <= MAX_METADATA_LENGTH) return text
  return "...\n\n" + text.slice(-MAX_METADATA_LENGTH)
}

function tail(text: string, maxLines: number, maxBytes: number) {
  const lines = text.split("\n")
  if (lines.length <= maxLines && Buffer.byteLength(text, "utf-8") <= maxBytes) {
    return {
      text,
      cut: false,
    }
  }

  const out: string[] = []
  let bytes = 0
  for (let i = lines.length - 1; i >= 0 && out.length < maxLines; i--) {
    const size = Buffer.byteLength(lines[i], "utf-8") + (out.length > 0 ? 1 : 0)
    if (bytes + size > maxBytes) {
      if (out.length === 0) {
        const buf = Buffer.from(lines[i], "utf-8")
        let start = buf.length - maxBytes
        if (start < 0) start = 0
        while (start < buf.length && (buf[start] & 0xc0) === 0x80) start++
        out.unshift(buf.subarray(start).toString("utf-8"))
      }
      break
    }
    out.unshift(lines[i])
    bytes += size
  }
  return {
    text: out.join("\n"),
    cut: true,
  }
}

const parse = Effect.fn("BashTool.parse")(function* (command: string, ps: boolean) {
  const tree = yield* Effect.promise(() => parser().then((p) => (ps ? p.ps : p.bash).parse(command)))
  if (!tree) throw new Error("Failed to parse command")
  return tree.rootNode
})

const ask = Effect.fn("BashTool.ask")(function* (ctx: Tool.Context, scan: Scan) {
  if (scan.dirs.size > 0) {
    const globs = Array.from(scan.dirs).map((dir) => {
      if (process.platform === "win32") return AppFileSystem.normalizePathPattern(path.join(dir, "*"))
      return path.join(dir, "*")
    })
    yield* ctx.ask({
      permission: "external_directory",
      patterns: globs,
      always: globs,
      metadata: {},
    })
  }

  if (scan.patterns.size === 0) return
  yield* ctx.ask({
    permission: "bash",
    patterns: Array.from(scan.patterns),
    always: Array.from(scan.always),
    metadata: {},
  })
})

function cmd(shell: string, name: string, command: string, cwd: string, env: NodeJS.ProcessEnv) {
  if (process.platform === "win32" && PS.has(name)) {
    return ChildProcess.make(shell, ["-NoLogo", "-NoProfile", "-NonInteractive", "-Command", command], {
      cwd,
      env,
      stdin: "ignore",
      detached: false,
    })
  }

  return ChildProcess.make(command, [], {
    shell,
    cwd,
    env,
    stdin: "ignore",
    detached: process.platform !== "win32",
  })
}

const parser = lazy(async () => {
  const { Parser } = await import("web-tree-sitter")
  const { default: treeWasm } = await import("web-tree-sitter/tree-sitter.wasm" as string, {
    with: { type: "wasm" },
  })
  const treePath = resolveWasm(treeWasm)
  await Parser.init({
    locateFile() {
      return treePath
    },
  })
  const { default: bashWasm } = await import("tree-sitter-bash/tree-sitter-bash.wasm" as string, {
    with: { type: "wasm" },
  })
  const { default: psWasm } = await import("tree-sitter-powershell/tree-sitter-powershell.wasm" as string, {
    with: { type: "wasm" },
  })
  const bashPath = resolveWasm(bashWasm)
  const psPath = resolveWasm(psWasm)
  const [bashLanguage, psLanguage] = await Promise.all([Language.load(bashPath), Language.load(psPath)])
  const bash = new Parser()
  bash.setLanguage(bashLanguage)
  const ps = new Parser()
  ps.setLanguage(psLanguage)
  return { bash, ps }
})

// TODO: we may wanna rename this tool so it works better on other shells
export const BashTool = Tool.define(
  "bash",
  Effect.gen(function* () {
    const spawner = yield* ChildProcessSpawner
    const fs = yield* AppFileSystem.Service
    const trunc = yield* Truncate.Service
    const plugin = yield* Plugin.Service

    const cygpath = Effect.fn("BashTool.cygpath")(function* (shell: string, text: string) {
      const lines = yield* spawner
        .lines(ChildProcess.make(shell, ["-lc", 'cygpath -w -- "$1"', "_", text]))
        .pipe(Effect.catch(() => Effect.succeed([] as string[])))
      const file = lines[0]?.trim()
      if (!file) return
      return AppFileSystem.normalizePath(file)
    })

    const resolvePath = Effect.fn("BashTool.resolvePath")(function* (text: string, root: string, shell: string) {
      if (process.platform === "win32") {
        if (Shell.posix(shell) && text.startsWith("/") && AppFileSystem.windowsPath(text) === text) {
          const file = yield* cygpath(shell, text)
          if (file) return file
        }
        return AppFileSystem.normalizePath(path.resolve(root, AppFileSystem.windowsPath(text)))
      }
      return path.resolve(root, text)
    })

    const argPath = Effect.fn("BashTool.argPath")(function* (arg: string, cwd: string, ps: boolean, shell: string) {
      const text = ps ? expand(arg, cwd, shell) : home(unquote(arg))
      const file = text && prefix(text)
      if (!file || dynamic(file, ps)) return
      const next = ps ? provider(file) : file
      if (!next) return
      return yield* resolvePath(next, cwd, shell)
    })

    const collect = Effect.fn("BashTool.collect")(function* (root: Node, cwd: string, ps: boolean, shell: string) {
      const scan: Scan = {
        dirs: new Set<string>(),
        patterns: new Set<string>(),
        always: new Set<string>(),
      }

      for (const node of commands(root)) {
        const command = parts(node)
        const tokens = command.map((item) => item.text)
        const cmd = ps ? tokens[0]?.toLowerCase() : tokens[0]

        if (cmd && FILES.has(cmd)) {
          for (const arg of pathArgs(command, ps)) {
            const resolved = yield* argPath(arg, cwd, ps, shell)
            log.info("resolved path", { arg, resolved })
            if (!resolved || Instance.containsPath(resolved)) continue
            const dir = (yield* fs.isDir(resolved)) ? resolved : path.dirname(resolved)
            scan.dirs.add(dir)
          }
        }

        if (tokens.length && (!cmd || !CWD.has(cmd))) {
          scan.patterns.add(source(node))
          scan.always.add(BashArity.prefix(tokens).join(" ") + " *")
        }
      }

      return scan
    })

    const shellEnv = Effect.fn("BashTool.shellEnv")(function* (ctx: Tool.Context, cwd: string) {
      const extra = yield* plugin.trigger(
        "shell.env",
        { cwd, sessionID: ctx.sessionID, callID: ctx.callID },
        { env: {} },
      )
      return {
        ...process.env,
        ...extra.env,
      }
    })

    const run = Effect.fn("BashTool.run")(function* (
      input: {
        shell: string
        name: string
        command: string
        cwd: string
        env: NodeJS.ProcessEnv
        timeout: number
        description: string
      },
      ctx: Tool.Context,
    ) {
      const bytes = Truncate.MAX_BYTES
      const lines = Truncate.MAX_LINES
      const keep = bytes * 2
      let full = ""
      let last = ""
      const list: Chunk[] = []
      let used = 0
      let file = ""
      let sink: ReturnType<typeof createWriteStream> | undefined
      let cut = false
      let expired = false
      let aborted = false

      yield* ctx.metadata({
        metadata: {
          output: "",
          description: input.description,
        },
      })

      const code: number | null = yield* Effect.scoped(
        Effect.gen(function* () {
          const handle = yield* spawner.spawn(cmd(input.shell, input.name, input.command, input.cwd, input.env))

          yield* Effect.forkScoped(
            Stream.runForEach(Stream.decodeText(handle.all), (chunk) => {
              const size = Buffer.byteLength(chunk, "utf-8")
              list.push({ text: chunk, size })
              used += size
              while (used > keep && list.length > 1) {
                const item = list.shift()
                if (!item) break
                used -= item.size
                cut = true
              }

              last = preview(last + chunk)

              if (file) {
                sink?.write(chunk)
              } else {
                full += chunk
                if (Buffer.byteLength(full, "utf-8") > bytes) {
                  return trunc.write(full).pipe(
                    Effect.andThen((next) =>
                      Effect.sync(() => {
                        file = next
                        cut = true
                        sink = createWriteStream(next, { flags: "a" })
                        full = ""
                      }),
                    ),
                    Effect.andThen(
                      ctx.metadata({
                        metadata: {
                          output: last,
                          description: input.description,
                        },
                      }),
                    ),
                  )
                }
              }

              return ctx.metadata({
                metadata: {
                  output: last,
                  description: input.description,
                },
              })
            }),
          )

          const abort = Effect.callback<void>((resume) => {
            if (ctx.abort.aborted) return resume(Effect.void)
            const handler = () => resume(Effect.void)
            ctx.abort.addEventListener("abort", handler, { once: true })
            return Effect.sync(() => ctx.abort.removeEventListener("abort", handler))
          })

          const timeout = Effect.sleep(`${input.timeout + 100} millis`)

          const exit = yield* Effect.raceAll([
            handle.exitCode.pipe(Effect.map((code) => ({ kind: "exit" as const, code }))),
            abort.pipe(Effect.map(() => ({ kind: "abort" as const, code: null }))),
            timeout.pipe(Effect.map(() => ({ kind: "timeout" as const, code: null }))),
          ])

          if (exit.kind === "abort") {
            aborted = true
            yield* handle.kill({ forceKillAfter: "3 seconds" }).pipe(Effect.orDie)
          }
          if (exit.kind === "timeout") {
            expired = true
            yield* handle.kill({ forceKillAfter: "3 seconds" }).pipe(Effect.orDie)
          }

          return exit.kind === "exit" ? exit.code : null
        }),
      ).pipe(Effect.orDie)

      const meta: string[] = []
      if (expired) {
        meta.push(
          `bash tool terminated command after exceeding timeout ${input.timeout} ms. If this command is expected to take longer and is not waiting for interactive input, retry with a larger timeout value in milliseconds.`,
        )
      }
      if (aborted) meta.push("User aborted the command")
      const raw = list.map((item) => item.text).join("")
      const end = tail(raw, lines, bytes)
      if (end.cut) cut = true
      if (!file && end.cut) {
        file = yield* trunc.write(raw)
      }

      let output = end.text
      if (!output) output = "(no output)"

      if (cut && file) {
        output = `...output truncated...\n\nFull output saved to: ${file}\n\n` + output
      }

      if (meta.length > 0) {
        output += "\n\n<bash_metadata>\n" + meta.join("\n") + "\n</bash_metadata>"
      }
      if (sink) {
        const stream = sink
        yield* Effect.promise(
          () =>
            new Promise<void>((resolve) => {
              stream.end(() => resolve())
              stream.on("error", () => resolve())
            }),
        )
      }

      return {
        title: input.description,
        metadata: {
          output: last || preview(output),
          exit: code,
          description: input.description,
          truncated: cut,
          ...(cut && file ? { outputPath: file } : {}),
        },
        output,
      }
    })

    return () =>
      Effect.sync(() => {
        const shell = Shell.acceptable()
        const name = Shell.name(shell)
        const chain =
          name === "powershell"
            ? "If the commands depend on each other and must run sequentially, avoid '&&' in this shell because Windows PowerShell 5.1 does not support it. Use PowerShell conditionals such as `cmd1; if ($?) { cmd2 }` when later commands must depend on earlier success."
            : "If the commands depend on each other and must run sequentially, use a single Bash call with '&&' to chain them together (e.g., `git add . && git commit -m \"message\" && git push`). For instance, if one operation must complete before another starts (like mkdir before cp, Write before Bash for git operations, or git add before git commit), run these operations sequentially instead."
        log.info("bash tool using shell", { shell })

        return {
          description: DESCRIPTION.replaceAll("${directory}", Instance.directory)
            .replaceAll("${os}", process.platform)
            .replaceAll("${shell}", name)
            .replaceAll("${chaining}", chain)
            .replaceAll("${maxLines}", String(Truncate.MAX_LINES))
            .replaceAll("${maxBytes}", String(Truncate.MAX_BYTES)),
          parameters: Parameters,
          execute: (params: z.infer<typeof Parameters>, ctx: Tool.Context) =>
            Effect.gen(function* () {
              const cwd = params.workdir
                ? yield* resolvePath(params.workdir, Instance.directory, shell)
                : Instance.directory
              if (params.timeout !== undefined && params.timeout < 0) {
                throw new Error(`Invalid timeout value: ${params.timeout}. Timeout must be a positive number.`)
              }
              const timeout = params.timeout ?? DEFAULT_TIMEOUT
              const ps = PS.has(name)
              const root = yield* parse(params.command, ps)
              const scan = yield* collect(root, cwd, ps, shell)
              if (!Instance.containsPath(cwd)) scan.dirs.add(cwd)
              yield* ask(ctx, scan)

              return yield* run(
                {
                  shell,
                  name,
                  command: params.command,
                  cwd,
                  env: yield* shellEnv(ctx, cwd),
                  timeout,
                  description: params.description,
                },
                ctx,
              )
            }),
        }
      })
  }),
)