/*
Copyright © 2026 Thomas von Dein

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package cfg

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log/slog"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"gopkg.in/yaml.v3"
)

type Automator struct {
	IsReachable bool
	Error       error
	Env         []string
	Cluster     *Cluster

	// all bash commands, .name must succeed first
	Name string `yaml:"name"`
	User string `yaml:"user"`
	Pass string `yaml:"pass"`
	Uri  string `yaml:"uri"`
}

type AutomatorRunner struct {
	Output string
	Error  error
}

func NewAutoEnv() []string {
	return []string{
		"PATH=" + os.Getenv("PATH"),
		"HOME=" + os.Getenv("HOME"),
		"SHELL=" + os.Getenv("SHELL"),
		"KUBECONFIG=" + os.Getenv("KUBECONFIG"),
	}
}

func NewAutomator() Automator {
	autocfg := filepath.Join([]string{os.Getenv("HOME"), ".config", "esctl", "automate.yaml"}...)

	auto := Automator{Env: NewAutoEnv()}

	if !fileExists(autocfg) {
		return auto
	}

	data, err := os.ReadFile(autocfg)
	if err != nil {
		auto.Error = fmt.Errorf("failed to read config file: %w", err)
		return auto
	}

	err = yaml.Unmarshal(data, &auto)
	if err != nil {
		auto.Error = fmt.Errorf("failed to unmarshal config file: %w", err)
		return auto
	}

	hasname := execute(auto.Name, auto.Env)
	if hasname.Error != nil {
		auto.Error = hasname.Error
		return auto
	}
	auto.Name = hasname.Output

	hasuser := execute(auto.User, auto.Env)
	if hasuser.Error != nil {
		auto.Error = hasuser.Error
		return auto
	}
	auto.User = hasuser.Output

	haspass := execute(auto.Pass, auto.Env)
	if haspass.Error != nil {
		auto.Error = haspass.Error
		return auto
	}
	auto.Pass = haspass.Output

	hasuri := execute(auto.Uri, auto.Env)
	if hasuri.Error != nil {
		auto.Error = hasuri.Error
		return auto
	}
	auto.Uri = hasuri.Output

	auto.IsReachable = true

	auto.Cluster = &Cluster{
		Name: auto.Name,
		Uri:  auto.Uri,
		User: auto.User,
		Pass: auto.Pass,
	}

	return auto
}

// FIXME: execute auto.Exec, if defined, in a go routine and let it run forever, might be a tunnel
func (auto *Automator) Exec() {}

// FIXME:  cache automator  results, only  check auto.Name  and if  it matches the cache use those vars, but run auto.Exec anyway
func (auto *Automator) Cache() {}

func execute(code string, env []string) *AutomatorRunner {
	timeoutCtx, cancel := context.WithTimeout(context.Background(),
		time.Duration(10)*time.Second)
	defer cancel()

	var cmd *exec.Cmd

	// pipe code into bash
	cmd = exec.CommandContext(timeoutCtx, "bash")
	cmd.Stdin = strings.NewReader(code)

	cmd.Env = env
	errbuf := &bytes.Buffer{}
	cmd.Stderr = errbuf

	done := make(chan bool)
	out := AutomatorRunner{}

	go func() {
		output, err := cmd.Output()

		out.Output = strings.TrimSpace(string(output))

		switch {
		case err != nil:
			out.Error = err
		case errbuf.Len() > 0:
			out.Error = fmt.Errorf(errbuf.String())
		case timeoutCtx.Err() == context.DeadlineExceeded:
			out.Error = errors.New("timed out")
		}

		slog.Debug("executed automator",
			"code", code,
			"output", out.Output,
			"error", out.Error)

		done <- true
	}()

	for {
		select {
		case <-done:
			return &out
		}
	}
}