package zeta

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// TestRecipe mirrors the zeta-toolchain recipe.lua validation rules:
// name (sanitize_name), version, summary, url required non-empty;
// sha256 empty-or-64-hex; deps non-empty strings; build_script required
// (build_system is always "custom" in v1).
func TestRecipe(t *testing.T) {
	valid := func() *Recipe {
		return &Recipe{
			Name:        "mytool",
			Version:     "1.0",
			Summary:     "Example custom-build package",
			URL:         "mytool-1.0.tar.gz",
			SHA256:      "",
			Deps:        []string{"libz"},
			BuildScript: "build.sh",
		}
	}

	tests := []struct {
		name    string
		mutate  func(r *Recipe)
		wantErr bool
	}{
		{"valid recipe", func(r *Recipe) {}, false},
		{"empty name", func(r *Recipe) { r.Name = "" }, true},
		{"name with slash", func(r *Recipe) { r.Name = "bad/name" }, true},
		{"name with leading dot", func(r *Recipe) { r.Name = ".hidden" }, true},
		{"empty version", func(r *Recipe) { r.Version = "" }, true},
		{"empty summary", func(r *Recipe) { r.Summary = "" }, true},
		{"empty url", func(r *Recipe) { r.URL = "" }, true},
		{"empty build_script", func(r *Recipe) { r.BuildScript = "" }, true},
		{"bad sha256", func(r *Recipe) { r.SHA256 = "zzz" }, true},
		{"short sha256 (63 hex)", func(r *Recipe) { r.SHA256 = strings.Repeat("a", 63) }, true},
		{"empty sha256 is allowed", func(r *Recipe) { r.SHA256 = "" }, false},
		{"64-hex sha256 allowed", func(r *Recipe) { r.SHA256 = strings.Repeat("f", 64) }, false},
		{"empty dep string", func(r *Recipe) { r.Deps = []string{"libz", ""} }, true},
		{"no deps allowed", func(r *Recipe) { r.Deps = nil }, false},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			r := valid()
			tt.mutate(r)
			err := r.Validate()
			if (err != nil) != tt.wantErr {
				t.Fatalf("Validate() error = %v, wantErr %v", err, tt.wantErr)
			}
		})
	}
}

func TestRecipeEmit(t *testing.T) {
	// Byte-exact render for the canonical custom recipe. Field keys are
	// padded to width 13 before " = ", matching recipe.lua and the
	// custom-demo/custom.recipe example.
	canonical := &Recipe{
		Name:        "mytool",
		Version:     "1.0",
		Summary:     "Example custom-build package",
		URL:         "mytool-1.0.tar.gz",
		SHA256:      "",
		Deps:        nil,
		BuildScript: "build.sh",
	}
	want := `return {
  name         = "mytool",
  version      = "1.0",
  summary      = "Example custom-build package",
  url          = "mytool-1.0.tar.gz",
  deps         = {},
  build_system = "custom",
  build_script = "build.sh",
}
`
	out, err := canonical.Emit()
	if err != nil {
		t.Fatalf("Emit() error = %v", err)
	}
	if out != want {
		t.Fatalf("Emit() mismatch:\n--- want ---\n%s\n--- got ---\n%s", want, out)
	}

	// Critical: empty SHA256 must OMIT the sha256 line entirely. recipe.lua
	// treats sha256 = "" as present (raw.sha256 ~= nil) and fails the
	// 64-hex check, so the line must never be emitted empty.
	if strings.Contains(out, "sha256") {
		t.Fatalf("Emit() with empty SHA256 must not contain a sha256 line, got:\n%s", out)
	}

	// Non-empty SHA256 emits the line after url and before deps.
	withSHA := *canonical
	withSHA.SHA256 = strings.Repeat("a", 64)
	outSHA, err := withSHA.Emit()
	if err != nil {
		t.Fatalf("Emit() with sha256 error = %v", err)
	}
	shaLine := `  sha256       = "` + strings.Repeat("a", 64) + `",`
	if !strings.Contains(outSHA, shaLine) {
		t.Fatalf("Emit() missing aligned sha256 line, got:\n%s", outSHA)
	}
	if !(strings.Index(outSHA, "url") < strings.Index(outSHA, "sha256") &&
		strings.Index(outSHA, "sha256") < strings.Index(outSHA, "deps")) {
		t.Fatalf("Emit() sha256 not between url and deps, got:\n%s", outSHA)
	}

	// deps render on one line; empty deps render as {}.
	withDeps := *canonical
	withDeps.Deps = []string{"libz", "libfoo"}
	outDeps, err := withDeps.Emit()
	if err != nil {
		t.Fatalf("Emit() with deps error = %v", err)
	}
	if !strings.Contains(outDeps, `  deps         = { "libz", "libfoo" },`) {
		t.Fatalf("Emit() deps line mismatch, got:\n%s", outDeps)
	}

	// Escape double quotes and newlines in summary and deps values.
	escaped := *canonical
	escaped.Summary = "say \"hi\"\nsecond line"
	escaped.Deps = []string{"say \"hi\""}
	outEsc, err := escaped.Emit()
	if err != nil {
		t.Fatalf("Emit() with escapes error = %v", err)
	}
	if !strings.Contains(outEsc, `  summary      = "say \"hi\"\nsecond line",`) {
		t.Fatalf("Emit() summary escape mismatch, got:\n%s", outEsc)
	}
	if !strings.Contains(outEsc, `  deps         = { "say \"hi\"" },`) {
		t.Fatalf("Emit() deps escape mismatch, got:\n%s", outEsc)
	}

	// Emit of an invalid recipe returns the validation error.
	invalid := *canonical
	invalid.Name = ""
	if _, err := invalid.Emit(); err == nil {
		t.Fatal("Emit() of invalid recipe should return an error")
	}
}

func TestRecipeGolden(t *testing.T) {
	r := &Recipe{
		Name:        "mytool",
		Version:     "1.0",
		Summary:     "Example custom-build package",
		URL:         "mytool-1.0.tar.gz",
		SHA256:      "",
		Deps:        nil,
		BuildScript: "build.sh",
	}
	out, err := r.Emit()
	if err != nil {
		t.Fatalf("Emit() error = %v", err)
	}

	// Golden files live at the repo root so todos 5/12/14 can share them.
	golden := filepath.Join("..", "..", "testdata", "golden", "mytool.recipe")

	if os.Getenv("UPDATE_GOLDEN") == "1" {
		if err := os.MkdirAll(filepath.Dir(golden), 0o755); err != nil {
			t.Fatalf("MkdirAll: %v", err)
		}
		if err := os.WriteFile(golden, []byte(out), 0o644); err != nil {
			t.Fatalf("WriteFile: %v", err)
		}
		t.Logf("wrote golden %s", golden)
		return
	}

	want, err := os.ReadFile(golden)
	if err != nil {
		t.Fatalf("ReadFile golden %s: %v (run with UPDATE_GOLDEN=1 to create)", golden, err)
	}
	if string(want) != out {
		t.Fatalf("golden mismatch:\n--- want ---\n%s\n--- got ---\n%s", want, out)
	}
}