// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0

package command

import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"strings"

	"github.com/hashicorp/hcl/v2/hclsimple"
	"github.com/hashicorp/nomad/api"
	"github.com/posener/complete"
)

type NodePoolApplyCommand struct {
	Meta
}

func (c *NodePoolApplyCommand) Name() string {
	return "node pool apply"
}

func (c *NodePoolApplyCommand) Synopsis() string {
	return "Create or update a node pool"
}

func (c *NodePoolApplyCommand) Help() string {
	helpText := `
Usage: nomad node pool apply [options] <input>

  Apply is used to create or update a node pool. The specification file is read
  from stdin by specifying "-", otherwise a path to the file is expected.

  If ACLs are enabled, this command requires a token with the 'write'
  capability in a 'node_pool' policy that matches the node pool being targeted.

General Options:

  ` + generalOptionsUsage(usageOptsDefault) + `

Apply Options:

  -json
    Parse the input as a JSON node pool specification.
`
	return strings.TrimSpace(helpText)
}

func (c *NodePoolApplyCommand) AutocompleteFlags() complete.Flags {
	return mergeAutocompleteFlags(c.Meta.AutocompleteFlags(FlagSetClient),
		complete.Flags{
			"-json": complete.PredictNothing,
		})
}

func (c *NodePoolApplyCommand) AutocompleteArgs() complete.Predictor {
	return complete.PredictOr(
		complete.PredictFiles("*.hcl"),
		complete.PredictFiles("*.json"),
	)
}

func (c *NodePoolApplyCommand) Run(args []string) int {
	var jsonInput bool

	flags := c.Meta.FlagSet(c.Name(), FlagSetClient)
	flags.Usage = func() { c.Ui.Output(c.Help()) }
	flags.BoolVar(&jsonInput, "json", false, "")

	if err := flags.Parse(args); err != nil {
		return 1
	}

	// Check that we only have one argument.
	args = flags.Args()
	if len(args) != 1 {
		c.Ui.Error("This command takes one argument: <input>")
		c.Ui.Error(commandErrorText(c))
		return 1
	}

	// Read input content.
	path := args[0]
	var content []byte
	var err error
	switch path {
	case "-":
		content, err = io.ReadAll(os.Stdin)
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Failed to read stdin: %v", err))
			return 1
		}
		// Set .hcl extension so the decoder doesn't fail.
		if !jsonInput {
			path = "stdin.nomad.hcl"
		}
	default:
		content, err = os.ReadFile(path)
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Failed to read file %q: %v", path, err))
			return 1
		}
	}

	// Parse input.
	var poolSpec nodePoolSpec
	if jsonInput {
		err = json.Unmarshal(content, &poolSpec.NodePool)
	} else {
		err = hclsimple.Decode(path, content, nil, &poolSpec)
	}
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Failed to parse input content: %v", err))
		return 1
	}

	// Make API request.
	client, err := c.Meta.Client()
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error initializing client: %s", err))
		return 1
	}

	_, err = client.NodePools().Register(poolSpec.NodePool, nil)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error applying node pool: %s", err))
		return 1
	}

	c.Ui.Output(fmt.Sprintf("Successfully applied node pool %q!", poolSpec.NodePool.Name))
	return 0
}

type nodePoolSpec struct {
	NodePool *api.NodePool `hcl:"node_pool,block"`
}