// Copyright (c) The OpenTofu Authors
// SPDX-License-Identifier: MPL-2.0
// Copyright (c) 2023 HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0

package command

import (
	"fmt"
	"path/filepath"
	"strings"

	"github.com/opentofu/opentofu/internal/addrs"
	"github.com/opentofu/opentofu/internal/command/arguments"
	"github.com/opentofu/opentofu/internal/command/views"
	"github.com/opentofu/opentofu/internal/configs"
	"github.com/opentofu/opentofu/internal/tfdiags"
	"github.com/opentofu/opentofu/internal/tofu"
)

// ValidateCommand is a Command implementation that validates the tofu files
type ValidateCommand struct {
	Meta
}

func (c *ValidateCommand) Run(rawArgs []string) int {
	// Parse and apply global view arguments
	common, rawArgs := arguments.ParseView(rawArgs)
	c.View.Configure(common)

	// Parse and validate flags
	args, diags := arguments.ParseValidate(rawArgs)
	if diags.HasErrors() {
		c.View.Diagnostics(diags)
		c.View.HelpPrompt("validate")
		return 1
	}

	view := views.NewValidate(args.ViewType, c.View)

	// After this point, we must only produce JSON output if JSON mode is
	// enabled, so all errors should be accumulated into diags and we'll
	// print out a suitable result at the end, depending on the format
	// selection. All returns from this point on must be tail-calls into
	// view.Results in order to produce the expected output.

	dir, err := filepath.Abs(args.Path)
	if err != nil {
		diags = diags.Append(fmt.Errorf("unable to locate module: %w", err))
		return view.Results(diags)
	}

	// Check for user-supplied plugin path
	if c.pluginPath, err = c.loadPluginPath(); err != nil {
		diags = diags.Append(fmt.Errorf("error loading plugin path: %w", err))
		return view.Results(diags)
	}

	// Inject variables from args into meta for static evaluation
	c.GatherVariables(args.Vars)

	validateDiags := c.validate(dir, args.TestDirectory, args.NoTests)
	diags = diags.Append(validateDiags)

	// Validating with dev overrides in effect means that the result might
	// not be valid for a stable release, so we'll warn about that in case
	// the user is trying to use "tofu validate" as a sort of pre-flight
	// check before submitting a change.
	diags = diags.Append(c.providerDevOverrideRuntimeWarnings())

	return view.Results(diags)
}

func (c *ValidateCommand) GatherVariables(args *arguments.Vars) {
	// FIXME the arguments package currently trivially gathers variable related
	// arguments in a heterogeneous slice, in order to minimize the number of
	// code paths gathering variables during the transition to this structure.
	// Once all commands that gather variables have been converted to this
	// structure, we could move the variable gathering code to the arguments
	// package directly, removing this shim layer.

	varArgs := args.All()
	items := make([]rawFlag, len(varArgs))
	for i := range varArgs {
		items[i].Name = varArgs[i].Name
		items[i].Value = varArgs[i].Value
	}
	c.Meta.variableArgs = rawFlags{items: &items}
}

func (c *ValidateCommand) validate(dir, testDir string, noTests bool) tfdiags.Diagnostics {
	var diags tfdiags.Diagnostics
	var cfg *configs.Config

	if noTests {
		cfg, diags = c.loadConfig(dir)
	} else {
		cfg, diags = c.loadConfigWithTests(dir, testDir)
	}
	if diags.HasErrors() {
		return diags
	}

	validate := func(cfg *configs.Config) tfdiags.Diagnostics {
		var diags tfdiags.Diagnostics

		opts, err := c.contextOpts()
		if err != nil {
			diags = diags.Append(err)
			return diags
		}

		tfCtx, ctxDiags := tofu.NewContext(opts)
		diags = diags.Append(ctxDiags)
		if ctxDiags.HasErrors() {
			return diags
		}

		return diags.Append(tfCtx.Validate(cfg))
	}

	diags = diags.Append(validate(cfg))

	if noTests {
		return diags
	}

	validatedModules := make(map[string]bool)

	// We'll also do a quick validation of the OpenTofu test files. These live
	// outside the OpenTofu graph so we have to do this separately.
	for _, file := range cfg.Module.Tests {

		diags = diags.Append(file.Validate())

		for _, run := range file.Runs {

			if run.Module != nil {
				// Then we can also validate the referenced modules, but we are
				// only going to do this is if they are local modules.
				//
				// Basically, local testing modules are something the user can
				// reasonably go and fix. If it's a module being downloaded from
				// the registry, the expectation is that the author of the
				// module should have ran `tofu validate` themselves.
				if _, ok := run.Module.Source.(addrs.ModuleSourceLocal); ok {

					if validated := validatedModules[run.Module.Source.String()]; !validated {

						// Since we can reference the same module twice, let's
						// not validate the same thing multiple times.

						validatedModules[run.Module.Source.String()] = true
						diags = diags.Append(validate(run.ConfigUnderTest))
					}

				}
			}

			diags = diags.Append(run.Validate())
		}
	}

	return diags
}

func (c *ValidateCommand) Synopsis() string {
	return "Check whether the configuration is valid"
}

func (c *ValidateCommand) Help() string {
	helpText := `
Usage: tofu [global options] validate [options]

  Validate the configuration files in a directory, referring only to the
  configuration and not accessing any remote services such as remote state,
  provider APIs, etc.

  Validate runs checks that verify whether a configuration is syntactically
  valid and internally consistent, regardless of any provided variables or
  existing state. It is thus primarily useful for general verification of
  reusable modules, including correctness of attribute names and value types.

  It is safe to run this command automatically, for example as a post-save
  check in a text editor or as a test step for a re-usable module in a CI
  system.

  Validation requires an initialized working directory with any referenced
  plugins and modules installed. To initialize a working directory for
  validation without accessing any configured remote backend, use:
      tofu init -backend=false

  To verify configuration in the context of a particular run (a particular
  target workspace, input variable values, etc), use the 'tofu plan'
  command instead, which includes an implied validation check.

Options:

  -compact-warnings     If OpenTofu produces any warnings that are not
                        accompanied by errors, show them in a more compact
                        form that includes only the summary messages.

  -consolidate-warnings If OpenTofu produces any warnings, no consolodation
                        will be performed. All locations, for all warnings
                        will be listed. Enabled by default.

  -consolidate-errors   If OpenTofu produces any errors, no consolodation
                        will be performed. All locations, for all errors
                        will be listed. Disabled by default

  -json                 Produce output in a machine-readable JSON format, 
                        suitable for use in text editor integrations and other 
                        automated systems. Always disables color.

  -no-color             If specified, output won't contain any color.

  -no-tests             If specified, OpenTofu will not validate test files.

  -test-directory=path  Set the OpenTofu test directory, defaults to "tests". When set, the
                        test command will search for test files in the current directory and
                        in the one specified by the flag.

  -var 'foo=bar'        Set a value for one of the input variables in the root
                        module of the configuration. Use this option more than
                        once to set more than one variable.

  -var-file=filename    Load variable values from the given file, in addition
                        to the default files terraform.tfvars and *.auto.tfvars.
                        Use this option more than once to include more than one
                        variables file.
`
	return strings.TrimSpace(helpText)
}