Add support for completing labels

internal/terraform/lang/config_block.go

@@ -13,12 +13,44 @@ type configBlockFactory interface {
 	New(*hclsyntax.Block) (ConfigBlock, error)
 }
 
+
+type labelCandidates map[string][]CompletionCandidate
+
+type completableLabels struct {
+	logger *log.Logger
+	block  Block
+	labels labelCandidates
+}
+
+func (cl *completableLabels) completionCandidatesAtPos(pos hcl.Pos) (CompletionCandidates, error) {
+	list := &completeList{
+		candidates: make([]CompletionCandidate, 0),
+	}
+	l, ok := cl.block.LabelAtPos(pos)
+	if !ok {
+		cl.logger.Printf("label not found at %#v", pos)
+		return list, nil
+	}
+	candidates, ok := cl.labels[l.Name]
+	if !ok {
+		cl.logger.Printf("label %q doesn't have completion candidates", l.Name)
+		return list, nil
+	}
+
+	cl.logger.Printf("completing label %q ...", l.Name)
+	for _, c := range candidates {
+		list.candidates = append(list.candidates, c)
+	}
+	list.Sort()
+
+	return list, nil
+}
+
 // completableBlock provides common completion functionality
 // for any Block implementation
 type completableBlock struct {
 	logger *log.Logger
-
-	block Block
+	block  Block
 }
 
 func (cb *completableBlock) completionCandidatesAtPos(pos hcl.Pos) (CompletionCandidates, error) {
@@ -27,7 +59,6 @@ func (cb *completableBlock) completionCandidatesAtPos(pos hcl.Pos) (CompletionCa
 	}
 
 	if !cb.block.PosInBody(pos) {
-		// Avoid autocompleting outside of body, for now
 		cb.logger.Println("avoiding completion outside of block body")
 		return nil, nil
 	}
@@ -37,6 +68,7 @@ func (cb *completableBlock) completionCandidatesAtPos(pos hcl.Pos) (CompletionCa
 		return nil, nil
 	}
 
+	// Completing the body (attributes and nested blocks)
 	b, ok := cb.block.BlockAtPos(pos)
 	if !ok {
 		// This should never happen as the completion
@@ -92,6 +124,23 @@ func (l *completeList) IsComplete() bool {
 	return true
 }
 
+type labelCandidate struct {
+	label  string
+	detail string
+}
+
+func (c *labelCandidate) Label() string {
+	return c.label
+}
+
+func (c *labelCandidate) Detail() string {
+	return c.detail
+}
+
+func (c *labelCandidate) Snippet(pos hcl.Pos) (hcl.Pos, string) {
+	return pos, c.label
+}
+
 type attributeCandidate struct {
 	Name string
 	Attr *Attribute

internal/terraform/lang/datasource_block.go

@@ -81,10 +81,6 @@ func (r *datasourceBlock) CompletionCandidatesAtPos(pos hcl.Pos) (CompletionCand
 		return nil, &noSchemaReaderErr{r.BlockType()}
 	}
 
-	cb := &completableBlock{
-		logger: r.logger,
-	}
-
 	var schemaBlock *tfjson.SchemaBlock
 	if r.Type() != "" {
 		rSchema, err := r.sr.DataSourceSchema(r.Type())
@@ -93,7 +89,39 @@ func (r *datasourceBlock) CompletionCandidatesAtPos(pos hcl.Pos) (CompletionCand
 		}
 		schemaBlock = rSchema.Block
 	}
-	cb.block = ParseBlock(r.hclBlock, r.Labels(), schemaBlock)
+	block := ParseBlock(r.hclBlock, r.Labels(), schemaBlock)
+
+	if block.PosInLabels(pos) {
+		dataSources, err := r.sr.DataSources()
+		if err != nil {
+			return nil, err
+		}
+
+		cl := &completableLabels{
+			logger: r.logger,
+			block:  block,
+			labels: labelCandidates{
+				"type": dataSourceCandidates(dataSources),
+			},
+		}
+
+		return cl.completionCandidatesAtPos(pos)
+	}
 
+	cb := &completableBlock{
+		logger: r.logger,
+		block:  block,
+	}
 	return cb.completionCandidatesAtPos(pos)
 }
+
+func dataSourceCandidates(dataSources []schema.DataSource) []CompletionCandidate {
+	candidates := []CompletionCandidate{}
+	for _, ds := range dataSources {
+		candidates = append(candidates, &labelCandidate{
+			label:  ds.Name,
+			detail: ds.Provider,
+		})
+	}
+	return candidates
+}

internal/terraform/lang/datasource_block_test.go

@@ -170,6 +170,25 @@ func TestDataSourceBlock_completionCandidatesAtPos(t *testing.T) {
 			[]renderedCandidate{},
 			errors.New("error getting schema"),
 		},
+		{
+			"datasource names",
+			`data "" "" {
+}`,
+			simpleSchema,
+			nil,
+			hcl.Pos{Line: 1, Column: 5, Byte: 6},
+			[]renderedCandidate{
+				{
+					Label:  "custom_ds",
+					Detail: "custom",
+					Snippet: renderedSnippet{
+						Pos:  hcl.Pos{Line: 1, Column: 5, Byte: 6},
+						Text: "custom_ds",
+					},
+				},
+			},
+			nil,
+		},
 	}
 
 	for i, tc := range testCases {

internal/terraform/lang/hcl_block.go

@@ -49,6 +49,27 @@ func (b *parsedBlock) Range() hcl.Range {
 	return b.hclBlock.Range()
 }
 
+func (b *parsedBlock) PosInLabels(pos hcl.Pos) bool {
+	for _, rng := range b.hclBlock.LabelRanges {
+		if rng.ContainsPos(pos) {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (b *parsedBlock) LabelAtPos(pos hcl.Pos) (*Label, bool) {
+	for i, rng := range b.hclBlock.LabelRanges {
+		if rng.ContainsPos(pos) {
+			// TODO: Guard against crashes when user sets label where we don't expect it
+			return b.labels[i], true
+		}
+	}
+
+	return nil, false
+}
+
 func (b *parsedBlock) PosInBody(pos hcl.Pos) bool {
 	for _, blockType := range b.BlockTypesMap {
 		for _, b := range blockType.BlockList {

internal/terraform/lang/provider_block.go

@@ -71,10 +71,6 @@ func (p *providerBlock) CompletionCandidatesAtPos(pos hcl.Pos) (CompletionCandid
 		return nil, &noSchemaReaderErr{p.BlockType()}
 	}
 
-	cb := &completableBlock{
-		logger: p.logger,
-	}
-
 	var schemaBlock *tfjson.SchemaBlock
 	if p.RawName() != "" {
 		pSchema, err := p.sr.ProviderConfigSchema(p.RawName())
@@ -83,7 +79,39 @@ func (p *providerBlock) CompletionCandidatesAtPos(pos hcl.Pos) (CompletionCandid
 		}
 		schemaBlock = pSchema.Block
 	}
-	cb.block = ParseBlock(p.hclBlock, p.Labels(), schemaBlock)
+	block := ParseBlock(p.hclBlock, p.Labels(), schemaBlock)
+
+	if block.PosInLabels(pos) {
+		providers, err := p.sr.Providers()
+		if err != nil {
+			return nil, err
+		}
+
+		cl := &completableLabels{
+			logger: p.logger,
+			block:  block,
+			labels: labelCandidates{
+				"name": providerCandidates(providers),
+			},
+		}
+
+		return cl.completionCandidatesAtPos(pos)
+	}
 
+	cb := &completableBlock{
+		logger: p.logger,
+		block:  block,
+	}
 	return cb.completionCandidatesAtPos(pos)
 }
+
+func providerCandidates(names []string) []CompletionCandidate {
+	candidates := []CompletionCandidate{}
+	for _, name := range names {
+		candidates = append(candidates, &labelCandidate{
+			label:  name,
+			detail: "provider",
+		})
+	}
+	return candidates
+}

internal/terraform/lang/provider_block_test.go

@@ -161,6 +161,26 @@ func TestProviderBlock_completionCandidatesAtPos(t *testing.T) {
 			[]renderedCandidate{},
 			errors.New("error getting schema"),
 		},
+		{
+			"provider names",
+			`provider "" {
+
+}`,
+			simpleSchema,
+			nil,
+			hcl.Pos{Line: 1, Column: 9, Byte: 10},
+			[]renderedCandidate{
+				{
+					Label:  "custom",
+					Detail: "provider",
+					Snippet: renderedSnippet{
+						Pos:  hcl.Pos{Line: 1, Column: 9, Byte: 10},
+						Text: "custom",
+					},
+				},
+			},
+			nil,
+		},
 	}
 
 	for i, tc := range testCases {

internal/terraform/lang/resource_block.go

@@ -81,10 +81,6 @@ func (r *resourceBlock) CompletionCandidatesAtPos(pos hcl.Pos) (CompletionCandid
 		return nil, &noSchemaReaderErr{r.BlockType()}
 	}
 
-	cb := &completableBlock{
-		logger: r.logger,
-	}
-
 	var schemaBlock *tfjson.SchemaBlock
 	if r.Type() != "" {
 		rSchema, err := r.sr.ResourceSchema(r.Type())
@@ -93,7 +89,38 @@ func (r *resourceBlock) CompletionCandidatesAtPos(pos hcl.Pos) (CompletionCandid
 		}
 		schemaBlock = rSchema.Block
 	}
-	cb.block = ParseBlock(r.hclBlock, r.Labels(), schemaBlock)
+	block := ParseBlock(r.hclBlock, r.Labels(), schemaBlock)
+
+	if block.PosInLabels(pos) {
+		resources, err := r.sr.Resources()
+		if err != nil {
+			return nil, err
+		}
+		cl := &completableLabels{
+			logger: r.logger,
+			block:  block,
+			labels: labelCandidates{
+				"type": resourceCandidates(resources),
+			},
+		}
 
+		return cl.completionCandidatesAtPos(pos)
+	}
+
+	cb := &completableBlock{
+		logger: r.logger,
+		block:  block,
+	}
 	return cb.completionCandidatesAtPos(pos)
 }
+
+func resourceCandidates(resources []schema.Resource) []CompletionCandidate {
+	candidates := []CompletionCandidate{}
+	for _, r := range resources {
+		candidates = append(candidates, &labelCandidate{
+			label:  r.Name,
+			detail: r.Provider,
+		})
+	}
+	return candidates
+}

internal/terraform/lang/resource_block_test.go

@@ -170,6 +170,26 @@ func TestResourceBlock_completionCandidatesAtPos(t *testing.T) {
 			[]renderedCandidate{},
 			errors.New("error getting schema"),
 		},
+		{
+			"resource names",
+			`resource "" "" {
+
+}`,
+			simpleSchema,
+			nil,
+			hcl.Pos{Line: 1, Column: 9, Byte: 10},
+			[]renderedCandidate{
+				{
+					Label:  "custom_rs",
+					Detail: "custom",
+					Snippet: renderedSnippet{
+						Pos:  hcl.Pos{Line: 1, Column: 9, Byte: 10},
+						Text: "custom_rs",
+					},
+				},
+			},
+			nil,
+		},
 	}
 
 	for i, tc := range testCases {

internal/terraform/lang/types.go

@@ -29,7 +29,9 @@ type ConfigBlock interface {
 // which keeps track of the related schema
 type Block interface {
 	BlockAtPos(pos hcl.Pos) (Block, bool)
+	LabelAtPos(pos hcl.Pos) (*Label, bool)
 	Range() hcl.Range
+	PosInLabels(pos hcl.Pos) bool
 	PosInBody(pos hcl.Pos) bool
 	PosInAttribute(pos hcl.Pos) bool
 	Attributes() map[string]*Attribute