package hcl2template

import (
	"fmt"

	"github.com/hashicorp/hcl/v2"
	"github.com/hashicorp/hcl/v2/hclparse"
	"github.com/hashicorp/packer/packer"
)

const (
	sourceLabel       = "source"
	variablesLabel    = "variables"
	buildLabel        = "build"
	communicatorLabel = "communicator"
)

var configSchema = &hcl.BodySchema{
	Blocks: []hcl.BlockHeaderSchema{
		{Type: sourceLabel, LabelNames: []string{"type", "name"}},
		{Type: variablesLabel},
		{Type: buildLabel},
		{Type: communicatorLabel, LabelNames: []string{"type", "name"}},
	},
}

type Parser struct {
	*hclparse.Parser

	BuilderSchemas packer.BuilderStore

	ProvisionersSchemas packer.ProvisionerStore

	PostProcessorsSchemas packer.PostProcessorStore
}

const (
	hcl2FileExt     = ".pkr.hcl"
	hcl2JsonFileExt = ".pkr.json"
)

func (p *Parser) parse(filename string) (*PackerConfig, hcl.Diagnostics) {

	hclFiles, jsonFiles, diags := GetHCL2Files(filename)

	var files []*hcl.File
	for _, filename := range hclFiles {
		f, moreDiags := p.ParseHCLFile(filename)
		diags = append(diags, moreDiags...)
		files = append(files, f)
	}
	for _, filename := range jsonFiles {
		f, moreDiags := p.ParseJSONFile(filename)
		diags = append(diags, moreDiags...)
		files = append(files, f)
	}
	if diags.HasErrors() {
		return nil, diags
	}

	cfg := &PackerConfig{}
	for _, file := range files {
		moreDiags := p.parseFile(file, cfg)
		diags = append(diags, moreDiags...)
	}

	return cfg, diags
}

// parseFile filename content into cfg.
//
// parseFile may be called multiple times with the same cfg on a different file.
//
// parseFile returns as complete a config as we can manage, even if there are
// errors, since a partial result can be useful for careful analysis by
// development tools such as text editor extensions.
func (p *Parser) parseFile(f *hcl.File, cfg *PackerConfig) hcl.Diagnostics {
	var diags hcl.Diagnostics

	content, moreDiags := f.Body.Content(configSchema)
	diags = append(diags, moreDiags...)

	for _, block := range content.Blocks {
		switch block.Type {
		case sourceLabel:
			source, moreDiags := p.decodeSource(block)
			diags = append(diags, moreDiags...)
			if moreDiags.HasErrors() {
				continue
			}

			ref := source.Ref()
			if existing := cfg.Sources[ref]; existing != nil {
				diags = append(diags, &hcl.Diagnostic{
					Severity: hcl.DiagError,
					Summary:  "Duplicate " + sourceLabel + " block",
					Detail: fmt.Sprintf("This "+sourceLabel+" block has the "+
						"same builder type and name as a previous block declared "+
						"at %s. Each "+sourceLabel+" must have a unique name per builder type.",
						existing.block.DefRange.Ptr()),
					Subject: source.block.DefRange.Ptr(),
				})
				continue
			}

			if cfg.Sources == nil {
				cfg.Sources = map[SourceRef]*Source{}
			}
			cfg.Sources[ref] = source

		case variablesLabel:
			if cfg.Variables == nil {
				cfg.Variables = PackerV1Variables{}
			}

			moreDiags := cfg.Variables.decodeConfig(block)
			if moreDiags.HasErrors() {
				continue
			}
			diags = append(diags, moreDiags...)

		case buildLabel:
			build, moreDiags := p.decodeBuildConfig(block)
			diags = append(diags, moreDiags...)
			if moreDiags.HasErrors() {
				continue
			}
			cfg.Builds = append(cfg.Builds, build)

		}
	}

	return diags
}