package stack

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

	"github.com/gruntwork-io/terragrunt/internal/configbridge"
	"github.com/gruntwork-io/terragrunt/internal/telemetry"
	"github.com/zclconf/go-cty/cty"

	"github.com/gruntwork-io/terragrunt/internal/runner/run"
	"github.com/gruntwork-io/terragrunt/internal/runner/runall"
	"github.com/gruntwork-io/terragrunt/pkg/config"
	"github.com/gruntwork-io/terragrunt/pkg/log"

	"github.com/gruntwork-io/terragrunt/internal/stacks/clean"
	"github.com/gruntwork-io/terragrunt/internal/stacks/generate"
	"github.com/gruntwork-io/terragrunt/internal/stacks/output"
	"github.com/gruntwork-io/terragrunt/internal/tips"
	"github.com/gruntwork-io/terragrunt/internal/vfs"
	"github.com/gruntwork-io/terragrunt/internal/worktrees"
	"github.com/gruntwork-io/terragrunt/pkg/options"
)

// RunGenerate runs the stack command.
func RunGenerate(ctx context.Context, l log.Logger, opts *options.TerragruntOptions) error {
	opts.TerragruntStackConfigPath = filepath.Join(opts.WorkingDir, config.DefaultStackFile)

	if opts.NoStackGenerate {
		l.Debugf("Skipping stack generation for %s", opts.TerragruntStackConfigPath)
		return nil
	}

	tips.GiveStackTargetTip(l, vfs.NewOSFS(), opts.WorkingDir, opts.Filters, opts.Tips)

	opts.StackAction = "generate"

	// Clean stack folders before calling `generate` when the `--source-update` flag is passed
	if opts.SourceUpdate {
		err := telemetry.TelemeterFromContext(ctx).Collect(ctx, "stack_clean", map[string]any{
			"stack_config_path": opts.TerragruntStackConfigPath,
			"working_dir":       opts.WorkingDir,
		}, func(ctx context.Context) error {
			l.Debugf("Running stack clean for %s, as part of generate command", opts.WorkingDir)
			return clean.CleanStacks(l, opts)
		})
		if err != nil {
			return fmt.Errorf("failed to clean stack directories under %q: %w", opts.WorkingDir, err)
		}
	}

	filters := opts.Filters

	gitFilters := filters.UniqueGitFilters()

	// Only create worktrees when git filter expressions are present
	var wts *worktrees.Worktrees

	if len(gitFilters) > 0 {
		var err error

		wts, err = worktrees.NewWorktrees(ctx, l, worktrees.WorktreeOpts{
			WorkingDir:     opts.WorkingDir,
			GitExpressions: gitFilters,
			Experiments:    opts.Experiments,
		})
		if err != nil {
			return fmt.Errorf("failed to create worktrees: %w", err)
		}

		defer func() {
			cleanupErr := wts.Cleanup(ctx, l)
			if cleanupErr != nil {
				l.Errorf("failed to cleanup worktrees: %v", cleanupErr)
			}
		}()
	}

	gen := generate.NewGenerator()

	err := telemetry.TelemeterFromContext(ctx).Collect(ctx, "stack_generate", map[string]any{
		"stack_config_path": opts.TerragruntStackConfigPath,
		"working_dir":       opts.WorkingDir,
	}, func(ctx context.Context) error {
		return gen.GenerateStacks(ctx, l, opts, wts)
	})
	if err != nil {
		return err
	}

	// After generation, hint when a literal stack filter left nested stacks ungenerated.
	funcsFor := configbridge.StackFuncFactory(ctx, l, opts)
	tips.GiveStackNestedGenerateTip(l, vfs.NewOSFS(), funcsFor, opts.WorkingDir, opts.Filters, opts.Tips)

	return nil
}

// Run executes the stack command.
func Run(ctx context.Context, l log.Logger, v run.Venv, opts *options.TerragruntOptions) error {
	opts.StackAction = "run"

	err := telemetry.TelemeterFromContext(ctx).Collect(ctx, "stack_run", map[string]any{
		"stack_config_path": opts.TerragruntStackConfigPath,
		"working_dir":       opts.WorkingDir,
	}, func(ctx context.Context) error {
		return RunGenerate(ctx, l, opts)
	})
	if err != nil {
		return err
	}

	return runall.Run(ctx, l, v, opts)
}

// RunOutput stack output.
func RunOutput(ctx context.Context, l log.Logger, opts *options.TerragruntOptions, index string) error {
	opts.StackAction = "output"
	opts.TerraformCommand = "output" // required for discovery exclude action matching in StackOutput

	var outputs cty.Value

	// collect outputs
	err := telemetry.TelemeterFromContext(ctx).Collect(ctx, "stack_output", map[string]any{
		"stack_config_path": opts.TerragruntStackConfigPath,
		"working_dir":       opts.WorkingDir,
	}, func(ctx context.Context) error {
		stackOutputs, err := output.StackOutput(ctx, l, opts)
		outputs = stackOutputs

		return err
	})
	if err != nil {
		return err
	}

	// Filter outputs based on index key
	filteredOutputs := FilterOutputs(outputs, index)

	// render outputs

	switch opts.StackOutputFormat {
	default:
		if err := PrintOutputs(opts.Writers.Writer, filteredOutputs); err != nil {
			return err
		}

	case rawOutputFormat:
		if err := PrintRawOutputs(opts, opts.Writers.Writer, filteredOutputs); err != nil {
			return err
		}

	case jsonOutputFormat:
		if err := PrintJSONOutput(opts.Writers.Writer, filteredOutputs); err != nil {
			return err
		}
	}

	return nil
}

// FilterOutputs filters the outputs based on the provided index key.
func FilterOutputs(outputs cty.Value, index string) cty.Value {
	if !outputs.IsKnown() || outputs.IsNull() || len(index) == 0 {
		return outputs
	}

	// Split the index into parts
	indexParts := strings.Split(index, ".")
	// Traverse the map using the index parts
	currentValue := outputs
	for _, part := range indexParts {
		// Check if the current value is a map or object
		if currentValue.Type().IsObjectType() || currentValue.Type().IsMapType() {
			valueMap := currentValue.AsValueMap()
			if nextValue, exists := valueMap[part]; exists {
				currentValue = nextValue
			} else {
				// If any part of the index path is not found, return NilVal
				return cty.NilVal
			}
		} else {
			// If the current value is not a map or object, return NilVal
			return cty.NilVal
		}
	}

	// Reconstruct the nested map structure
	nested := currentValue
	for i := len(indexParts) - 1; i >= 0; i-- {
		nested = cty.ObjectVal(map[string]cty.Value{
			indexParts[i]: nested,
		})
	}

	return nested
}

// RunClean recursively removes all stack directories under the specified WorkingDir.
func RunClean(ctx context.Context, l log.Logger, opts *options.TerragruntOptions) error {
	telemeter := telemetry.TelemeterFromContext(ctx)

	err := telemeter.Collect(ctx, "stack_clean", map[string]any{
		"stack_config_path": opts.TerragruntStackConfigPath,
		"working_dir":       opts.WorkingDir,
	}, func(ctx context.Context) error {
		return clean.CleanStacks(l, opts)
	})
	if err != nil {
		return fmt.Errorf("failed to clean stack directories under %q: %w", opts.WorkingDir, err)
	}

	return nil
}
