package cloud

import (
	"encoding/json"
	"fmt"

	"github.com/hashicorp/terraform/internal/backend"
	"github.com/hashicorp/terraform/internal/configs"
	"github.com/hashicorp/terraform/internal/terraform"
	"github.com/hashicorp/terraform/internal/tfdiags"
	ctyjson "github.com/zclconf/go-cty/cty/json"
)

func allowedSourceType(source terraform.ValueSourceType) bool {
	return source == terraform.ValueFromNamedFile || source == terraform.ValueFromCLIArg || source == terraform.ValueFromEnvVar
}

// ParseCloudRunVariables accepts a mapping of unparsed values and a mapping of variable
// declarations and returns a name/value variable map appropriate for an API run context,
// that is, containing declared string variables only sourced from non-file inputs like CLI args
// and environment variables. However, all variable parsing diagnostics are returned
// in order to allow callers to short circuit cloud runs that contain variable
// declaration or parsing errors. The only exception is that missing required values are not
// considered errors because they may be defined within the cloud workspace.
func ParseCloudRunVariables(vv map[string]backend.UnparsedVariableValue, decls map[string]*configs.Variable) (map[string]string, tfdiags.Diagnostics) {
	declared, diags := backend.ParseDeclaredVariableValues(vv, decls)
	_, undedeclaredDiags := backend.ParseUndeclaredVariableValues(vv, decls)
	diags = diags.Append(undedeclaredDiags)

	ret := make(map[string]string, len(declared))

	// Even if there are parsing or declaration errors, populate the return map with the
	// variables that could be used for cloud runs
	for name, v := range declared {
		if !allowedSourceType(v.SourceType) {
			continue
		}

		valueData, err := ctyjson.Marshal(v.Value, v.Value.Type())
		if err != nil {
			return nil, diags.Append(fmt.Errorf("error marshaling input variable value as json: %w", err))
		}
		var variableValue string
		if err = json.Unmarshal(valueData, &variableValue); err != nil {
			// This should never happen since cty marshaled the value to begin with without error
			return nil, diags.Append(fmt.Errorf("error unmarshaling run variable: %w", err))
		}
		ret[name] = variableValue
	}

	return ret, diags
}