package main

import (
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
)

type Request struct {
	Action  string `json:"action"`
	Path    string `json:"path"`
	Content string `json:"content,omitempty"`
	Find    string `json:"find,omitempty"`
	Replace string `json:"replace,omitempty"`
	All     bool   `json:"all,omitempty"`
}

type Response struct {
	OK      bool   `json:"ok"`
	Content string `json:"content,omitempty"`
	Error   string `json:"error,omitempty"`
	Count   int    `json:"count,omitempty"`
}

func main() {
	var req Request
	if err := json.NewDecoder(os.Stdin).Decode(&req); err != nil {
		respond(Response{OK: false, Error: err.Error()})
		return
	}

	switch req.Action {
	case "read":
		data, err := os.ReadFile(req.Path)
		if err != nil {
			respond(Response{OK: false, Error: err.Error()})
			return
		}
		respond(Response{OK: true, Content: string(data)})

	case "write":
		os.MkdirAll(filepath.Dir(req.Path), 0755)
		if err := os.WriteFile(req.Path, []byte(req.Content), 0644); err != nil {
			respond(Response{OK: false, Error: err.Error()})
			return
		}
		respond(Response{OK: true})

	case "append":
		os.MkdirAll(filepath.Dir(req.Path), 0755)
		f, err := os.OpenFile(req.Path, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0644)
		if err != nil {
			respond(Response{OK: false, Error: err.Error()})
			return
		}
		defer f.Close()
		if _, err = f.WriteString(req.Content); err != nil {
			respond(Response{OK: false, Error: err.Error()})
			return
		}
		respond(Response{OK: true})

	case "replace":
		data, err := os.ReadFile(req.Path)
		if err != nil {
			respond(Response{OK: false, Error: err.Error()})
			return
		}
		old := string(data)
		count := strings.Count(old, req.Find)
		if count == 0 {
			respond(Response{OK: false, Error: "pattern not found"})
			return
		}
		n := 1
		if req.All {
			n = -1
		}
		newData := strings.Replace(old, req.Find, req.Replace, n)
		if err := os.WriteFile(req.Path, []byte(newData), 0644); err != nil {
			respond(Response{OK: false, Error: err.Error()})
			return
		}
		if req.All {
			respond(Response{OK: true, Count: count})
		} else {
			respond(Response{OK: true, Count: 1})
		}

	default:
		respond(Response{OK: false, Error: "unknown action: " + req.Action})
	}
}

func respond(r Response) {
	json.NewEncoder(os.Stdout).Encode(r)
}