package bundle

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

func TestWriteBundleCreatesCompleteBundle(t *testing.T) {
	sourceRoot := t.TempDir()
	outputRoot := filepath.Join(t.TempDir(), "bundle")
	writeFile(t, sourceRoot, "report.md", "# Report\n")
	writeFile(t, sourceRoot, "summary.txt", "Summary\n")
	created := time.Date(2026, 5, 30, 11, 10, 0, 0, time.UTC)

	manifest, err := WriteBundle(WriteBundleOptions{
		Root:    outputRoot,
		ID:      "reports.writer",
		Created: created,
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "summary.txt"), Path: "nested/summary.txt"},
			{SourcePath: filepath.Join(sourceRoot, "report.md"), Path: "report.md"},
		},
	})
	if err != nil {
		t.Fatalf("WriteBundle() error = %v", err)
	}

	if !manifest.Created.Equal(created) {
		t.Fatalf("created = %s, want %s", manifest.Created, created)
	}
	if paths := manifestPaths(manifest); !reflect.DeepEqual(paths, []string{"nested/summary.txt", "report.md"}) {
		t.Fatalf("paths = %v, want caller order", paths)
	}
	if got := readFile(t, outputRoot, "nested/summary.txt"); got != "Summary\n" {
		t.Fatalf("nested summary = %q", got)
	}
	if got := readFile(t, outputRoot, "report.md"); got != "# Report\n" {
		t.Fatalf("report = %q", got)
	}
	loaded, err := LoadManifest(outputRoot)
	if err != nil {
		t.Fatalf("LoadManifest() error = %v", err)
	}
	if !reflect.DeepEqual(loaded, manifest) {
		t.Fatalf("loaded manifest = %#v, want %#v", loaded, manifest)
	}
	if err := ValidateBundle(outputRoot, loaded); err != nil {
		t.Fatalf("ValidateBundle() error = %v", err)
	}
}

func TestWriteBundleDefaultsCreated(t *testing.T) {
	sourceRoot := t.TempDir()
	outputRoot := filepath.Join(t.TempDir(), "bundle")
	writeFile(t, sourceRoot, "report.md", "# Report\n")
	before := time.Now().UTC()

	manifest, err := WriteBundle(WriteBundleOptions{
		Root: outputRoot,
		ID:   "reports.created",
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "report.md"), Path: "report.md"},
		},
	})
	if err != nil {
		t.Fatalf("WriteBundle() error = %v", err)
	}
	after := time.Now().UTC()
	if manifest.Created.Before(before) || manifest.Created.After(after) {
		t.Fatalf("created = %s, want between %s and %s", manifest.Created, before, after)
	}
}

func TestWriteBundleRejectsDuplicatePaths(t *testing.T) {
	sourceRoot := t.TempDir()
	writeFile(t, sourceRoot, "report.md", "# Report\n")

	_, err := WriteBundle(WriteBundleOptions{
		Root: filepath.Join(t.TempDir(), "bundle"),
		ID:   "reports.duplicate",
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "report.md"), Path: "report.md"},
			{SourcePath: filepath.Join(sourceRoot, "report.md"), Path: "report.md"},
		},
	})
	if err == nil || !strings.Contains(err.Error(), "duplicates") {
		t.Fatalf("WriteBundle() error = %v, want duplicate path error", err)
	}
}

func TestWriteBundleRejectsSymlinkSource(t *testing.T) {
	sourceRoot := t.TempDir()
	writeFile(t, sourceRoot, "target.md", "# Report\n")
	linkPath := filepath.Join(sourceRoot, "link.md")
	if err := os.Symlink("target.md", linkPath); err != nil {
		t.Skipf("symlink unavailable: %v", err)
	}

	_, err := WriteBundle(WriteBundleOptions{
		Root: filepath.Join(t.TempDir(), "bundle"),
		ID:   "reports.symlink",
		Files: []BundleFile{
			{SourcePath: linkPath, Path: "report.md"},
		},
	})
	if err == nil || !strings.Contains(err.Error(), "regular file") {
		t.Fatalf("WriteBundle() error = %v, want regular file error", err)
	}
}

func TestWriteBundleDoesNotOverwriteByDefault(t *testing.T) {
	sourceRoot := t.TempDir()
	outputRoot := filepath.Join(t.TempDir(), "bundle")
	writeFile(t, sourceRoot, "report.md", "old\n")
	if _, err := WriteBundle(WriteBundleOptions{
		Root: outputRoot,
		ID:   "reports.old",
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "report.md"), Path: "report.md"},
		},
	}); err != nil {
		t.Fatalf("initial WriteBundle() error = %v", err)
	}
	writeFile(t, sourceRoot, "report.md", "new\n")

	_, err := WriteBundle(WriteBundleOptions{
		Root: outputRoot,
		ID:   "reports.new",
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "report.md"), Path: "report.md"},
		},
	})
	if err == nil || !strings.Contains(err.Error(), "already exists") {
		t.Fatalf("WriteBundle() error = %v, want exists error", err)
	}
	if got := readFile(t, outputRoot, "report.md"); got != "old\n" {
		t.Fatalf("report = %q, want old content", got)
	}
}

func TestWriteBundleOverwritesExistingRoot(t *testing.T) {
	sourceRoot := t.TempDir()
	outputRoot := filepath.Join(t.TempDir(), "bundle")
	writeFile(t, sourceRoot, "old.md", "old\n")
	if _, err := WriteBundle(WriteBundleOptions{
		Root: outputRoot,
		ID:   "reports.old",
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "old.md"), Path: "old.md"},
		},
	}); err != nil {
		t.Fatalf("initial WriteBundle() error = %v", err)
	}
	writeFile(t, sourceRoot, "new.md", "new\n")

	manifest, err := WriteBundle(WriteBundleOptions{
		Root:      outputRoot,
		ID:        "reports.new",
		Overwrite: true,
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "new.md"), Path: "new.md"},
		},
	})
	if err != nil {
		t.Fatalf("WriteBundle(overwrite) error = %v", err)
	}

	if manifest.ID != "reports.new" {
		t.Fatalf("manifest id = %q, want reports.new", manifest.ID)
	}
	if _, err := os.Stat(filepath.Join(outputRoot, "old.md")); !os.IsNotExist(err) {
		t.Fatalf("old file stat error = %v, want not exist", err)
	}
	if got := readFile(t, outputRoot, "new.md"); got != "new\n" {
		t.Fatalf("new file = %q", got)
	}
	if err := ValidateBundle(outputRoot, manifest); err != nil {
		t.Fatalf("ValidateBundle() error = %v", err)
	}
}

func TestWriteBundleKeepsExistingRootWhenReplacementBuildFails(t *testing.T) {
	sourceRoot := t.TempDir()
	outputRoot := filepath.Join(t.TempDir(), "bundle")
	writeFile(t, sourceRoot, "report.md", "old\n")
	oldManifest, err := WriteBundle(WriteBundleOptions{
		Root: outputRoot,
		ID:   "reports.old",
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "report.md"), Path: "report.md"},
		},
	})
	if err != nil {
		t.Fatalf("initial WriteBundle() error = %v", err)
	}

	_, err = WriteBundle(WriteBundleOptions{
		Root:      outputRoot,
		ID:        "reports.new",
		Overwrite: true,
		Files: []BundleFile{
			{SourcePath: filepath.Join(sourceRoot, "missing.md"), Path: "report.md"},
		},
	})
	if err == nil {
		t.Fatal("WriteBundle(overwrite) error = nil, want missing source error")
	}

	loaded, err := LoadManifest(outputRoot)
	if err != nil {
		t.Fatalf("LoadManifest() error = %v", err)
	}
	if !reflect.DeepEqual(loaded, oldManifest) {
		t.Fatalf("loaded manifest = %#v, want old manifest %#v", loaded, oldManifest)
	}
	if got := readFile(t, outputRoot, "report.md"); got != "old\n" {
		t.Fatalf("report = %q, want old content", got)
	}
}

func readFile(t *testing.T, root, relative string) string {
	t.Helper()
	data, err := os.ReadFile(filepath.Join(root, filepath.FromSlash(relative)))
	if err != nil {
		t.Fatalf("read %s: %v", relative, err)
	}
	return string(data)
}