feat(completion): unify shell wrappers behind task __complete

internal/complete/engine.go

@@ -0,0 +1,171 @@
+package complete
+
+import (
+	"strings"
+
+	"github.com/spf13/pflag"
+
+	"github.com/go-task/task/v3"
+	"github.com/go-task/task/v3/internal/templater"
+	"github.com/go-task/task/v3/taskfile/ast"
+)
+
+// Complete is the single entry point used by `task __complete`. e may be nil
+// when the Taskfile failed to load; flag completion still works in that case.
+func Complete(e *task.Executor, fs *pflag.FlagSet, args []string) ([]Suggestion, Directive) {
+	knownTasks := taskNames(e)
+	ctx := parseContext(args, knownTasks, fs)
+
+	if ctx.afterDash {
+		return nil, DirectiveDefault
+	}
+
+	if ctx.prev != "" {
+		if flag := matchFlagName(fs, ctx.prev); flag != nil && flagTakesValue(flag) {
+			return completeFlagValue(flag.Name, ctx.toComplete)
+		}
+	}
+
+	if strings.HasPrefix(ctx.toComplete, "-") {
+		if eqIdx := strings.Index(ctx.toComplete, "="); eqIdx != -1 {
+			flagWord := ctx.toComplete[:eqIdx]
+			partial := ctx.toComplete[eqIdx+1:]
+			if f := matchFlagName(fs, flagWord); f != nil && flagTakesValue(f) {
+				return completeFlagValue(f.Name, partial)
+			}
+		}
+		return listFlags(fs), DirectiveNoFileComp
+	}
+
+	if ctx.taskName != "" && e != nil && e.Taskfile != nil {
+		return completeTaskVars(e, ctx.taskName, ctx.toComplete)
+	}
+
+	return completeTaskNames(e), DirectiveNoFileComp
+}
+
+func taskNames(e *task.Executor) []string {
+	if e == nil || e.Taskfile == nil {
+		return nil
+	}
+	var out []string
+	for t := range e.Taskfile.Tasks.Values(nil) {
+		if t.Internal {
+			continue
+		}
+		out = append(out, strings.TrimSuffix(t.Task, ":"))
+		for _, alias := range t.Aliases {
+			out = append(out, strings.TrimSuffix(alias, ":"))
+		}
+	}
+	return out
+}
+
+func completeTaskNames(e *task.Executor) []Suggestion {
+	if e == nil || e.Taskfile == nil {
+		return nil
+	}
+	tasks, err := e.GetTaskList(task.FilterOutInternal)
+	if err != nil {
+		return nil
+	}
+	out := make([]Suggestion, 0, len(tasks))
+	for _, t := range tasks {
+		out = append(out, Suggestion{
+			Value:       strings.TrimSuffix(t.Task, ":"),
+			Description: t.Desc,
+		})
+		for _, alias := range t.Aliases {
+			out = append(out, Suggestion{
+				Value:       strings.TrimSuffix(alias, ":"),
+				Description: t.Desc,
+			})
+		}
+	}
+	return out
+}
+
+func completeFlagValue(flagName, toComplete string) ([]Suggestion, Directive) {
+	if dir, ok := flagDirective[flagName]; ok {
+		switch dir {
+		case DirectiveFilterFileExt:
+			suggs := make([]Suggestion, 0, len(taskfileExtensions))
+			for _, ext := range taskfileExtensions {
+				suggs = append(suggs, Suggestion{Value: ext})
+			}
+			return suggs, DirectiveFilterFileExt
+		case DirectiveFilterDirs:
+			return nil, DirectiveFilterDirs
+		default:
+			return nil, DirectiveDefault
+		}
+	}
+
+	if values, ok := flagEnums[flagName]; ok {
+		out := make([]Suggestion, 0, len(values))
+		for _, v := range values {
+			out = append(out, Suggestion{Value: v})
+		}
+		_ = toComplete
+		return out, DirectiveNoFileComp
+	}
+
+	return nil, DirectiveDefault
+}
+
+func completeTaskVars(e *task.Executor, taskName, toComplete string) ([]Suggestion, Directive) {
+	compiled, err := e.FastCompiledTask(&task.Call{Task: taskName})
+	if err != nil || compiled == nil || compiled.Requires == nil {
+		return nil, DirectiveNoFileComp
+	}
+
+	cache := &templater.Cache{Vars: compiled.Vars}
+	out := make([]Suggestion, 0, 8)
+	for _, v := range compiled.Requires.Vars {
+		if v == nil || v.Name == "" {
+			continue
+		}
+		values := enumValues(v.Enum, cache)
+		if len(values) == 0 {
+			out = append(out, Suggestion{Value: v.Name + "="})
+			continue
+		}
+		for _, val := range values {
+			out = append(out, Suggestion{Value: v.Name + "=" + val})
+		}
+	}
+	_ = toComplete
+	if len(out) == 0 {
+		return nil, DirectiveNoFileComp
+	}
+	return out, DirectiveNoSpace | DirectiveNoFileComp
+}
+
+func enumValues(enum *ast.Enum, cache *templater.Cache) []string {
+	if enum == nil {
+		return nil
+	}
+	if len(enum.Value) > 0 {
+		return enum.Value
+	}
+	if enum.Ref == "" {
+		return nil
+	}
+	resolved := templater.ResolveRef(enum.Ref, cache)
+	if cache.Err() != nil {
+		return nil
+	}
+	arr, ok := resolved.([]any)
+	if !ok {
+		return nil
+	}
+	out := make([]string, 0, len(arr))
+	for _, item := range arr {
+		s, ok := item.(string)
+		if !ok {
+			return nil
+		}
+		out = append(out, s)
+	}
+	return out
+}