package service

import (
	"context"
	"errors"
	"strings"
	"testing"

	"sourcecraft.dev/bigbes/sr-ht-spec/core"
)

func TestReadDocumentResolvesTheApprovedHeadByDefault(t *testing.T) {
	svc, root := newService(t)
	sp := newSpace(t, root, 1)
	ctx := context.Background()

	first := commitFiles(t, sp, sp.ApprovedBranch(), 1, map[string][]byte{
		"specs/0007-storage.md": doc("SPEC-0007", "Storage model", "first"),
	})
	second := commitFiles(t, sp, sp.ApprovedBranch(), 2, map[string][]byte{
		"specs/0007-storage.md": doc("SPEC-0007", "Storage model", "second"),
	})

	got, err := svc.ReadDocument(ctx, sp, ApprovedRev, "specs/0007-storage.md")
	if err != nil {
		t.Fatalf("ReadDocument: %v", err)
	}
	if !contains(got.Data, "second") {
		t.Errorf("approved read returned %q, want the newest revision", got.Data)
	}
	if got.Rev != second.String() {
		t.Errorf("Rev = %s, want the resolved approved head %s", got.Rev, second)
	}
	if got.Blob == "" {
		t.Error("Blob is empty; it is the render cache key")
	}

	// The same call with a pinned revision is the same code path with a
	// different revision — one storage tier, no checkout.
	pinned, err := svc.ReadDocument(ctx, sp, first.String(), "specs/0007-storage.md")
	if err != nil {
		t.Fatalf("pinned ReadDocument: %v", err)
	}
	if !contains(pinned.Data, "first") {
		t.Errorf("pinned read returned %q, want the pinned revision", pinned.Data)
	}
	if pinned.Blob == got.Blob {
		t.Error("two revisions of one document share a blob sha")
	}
}

// A draft must never be served by default: doing so would poison every
// downstream agent context with unreviewed text.
func TestReadDocumentDoesNotServeAProposalByDefault(t *testing.T) {
	svc, root := newService(t)
	sp := newSpace(t, root, 1)
	ctx := context.Background()

	commitFiles(t, sp, sp.ApprovedBranch(), 1, map[string][]byte{
		"specs/0007-storage.md": doc("SPEC-0007", "Storage model", "approved"),
	})
	cutBranch(t, sp, "proposals/1", sp.ApprovedBranch())
	commitFiles(t, sp, "proposals/1", 2, map[string][]byte{
		"specs/0007-storage.md": doc("SPEC-0007", "Storage model", "draft"),
	})

	approved, err := svc.ReadDocument(ctx, sp, ApprovedRev, "specs/0007-storage.md")
	if err != nil {
		t.Fatalf("ReadDocument: %v", err)
	}
	if !contains(approved.Data, "approved") {
		t.Fatalf("default read returned the draft: %q", approved.Data)
	}
	draft, err := svc.ReadDocument(ctx, sp, "proposals/1", "specs/0007-storage.md")
	if err != nil {
		t.Fatalf("ReadDocument at the proposal branch: %v", err)
	}
	if !contains(draft.Data, "draft") {
		t.Errorf("proposal read returned %q", draft.Data)
	}
}

func TestReadDocumentMapsAbsenceOntoErrNotFound(t *testing.T) {
	svc, root := newService(t)
	sp := newSpace(t, root, 1)
	ctx := context.Background()

	tests := []struct {
		name string
		rev  string
		path string
	}{
		{"missing document", ApprovedRev, "specs/nope.md"},
		{"unknown revision", "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef", "specs/nope.md"},
		// Revision arithmetic is not a usable revision; it must not be
		// distinguishable from an absent one by probing.
		{"revision arithmetic", "main^2", "specs/nope.md"},
	}
	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			if _, err := svc.ReadDocument(ctx, sp, tc.rev, tc.path); !errors.Is(err, ErrNotFound) {
				t.Fatalf("err = %v, want ErrNotFound", err)
			}
		})
	}
}

func TestListDocumentsReturnsEveryDocumentAtARevision(t *testing.T) {
	svc, root := newService(t)
	sp := newSpace(t, root, 1)
	ctx := context.Background()

	commitFiles(t, sp, sp.ApprovedBranch(), 1, map[string][]byte{
		"specs/0007-storage.md": doc("SPEC-0007", "Storage", "body"),
		"notes/scratch.md":      doc("NOTE-0001", "Scratch", "body"),
		"attachment.png":        []byte("\x89PNG not a document"),
		core.PolicyFile:         []byte("review:\n  auto_merge: [notes/**]\n"),
	})

	docs, err := svc.ListDocuments(ctx, sp, ApprovedRev)
	if err != nil {
		t.Fatalf("ListDocuments: %v", err)
	}
	var paths []string
	for _, d := range docs {
		paths = append(paths, d.Path)
	}
	want := []string{"notes/scratch.md", "specs/0007-storage.md"}
	if len(paths) != len(want) {
		t.Fatalf("paths = %v, want %v (documents only)", paths, want)
	}
	for i := range want {
		if paths[i] != want[i] {
			t.Fatalf("paths = %v, want %v", paths, want)
		}
	}
}

func TestPolicyReadsTheVersionedSpecYml(t *testing.T) {
	svc, root := newService(t)
	sp := newSpace(t, root, 1)
	ctx := context.Background()

	// A space with no .spec.yml gets the house contract and nothing
	// auto-merged: the fail-closed direction.
	pol, err := svc.Policy(ctx, sp, ApprovedRev)
	if err != nil {
		t.Fatalf("Policy: %v", err)
	}
	if pol.AutoMerges("notes/x.md") {
		t.Error("a space with no policy auto-merged a path")
	}
	if len(pol.Schema.Required) == 0 {
		t.Error("default policy carries no required keys")
	}

	before := commitFiles(t, sp, sp.ApprovedBranch(), 1, map[string][]byte{
		core.PolicyFile: []byte("review:\n  auto_merge: [notes/**]\n"),
	})
	pol, err = svc.Policy(ctx, sp, ApprovedRev)
	if err != nil {
		t.Fatalf("Policy: %v", err)
	}
	if !pol.AutoMerges("notes/x.md") || pol.AutoMerges("specs/x.md") {
		t.Errorf("auto_merge = %v", pol.Review.AutoMerge)
	}

	// Policy is read at a revision, which is what makes a policy change
	// reviewable like any other change.
	commitFiles(t, sp, sp.ApprovedBranch(), 2, map[string][]byte{
		core.PolicyFile: []byte("review:\n  auto_merge: []\n"),
	})
	pinned, err := svc.Policy(ctx, sp, before.String())
	if err != nil {
		t.Fatalf("pinned Policy: %v", err)
	}
	if !pinned.AutoMerges("notes/x.md") {
		t.Error("a pinned policy read returned the newer policy")
	}
}

func TestPolicyFailsOnAnUnparseableSpecYml(t *testing.T) {
	svc, root := newService(t)
	sp := newSpace(t, root, 1)

	commitFiles(t, sp, sp.ApprovedBranch(), 1, map[string][]byte{
		core.PolicyFile: []byte("review:\n  auto-merge: [notes/**]\n"),
	})
	_, err := svc.Policy(context.Background(), sp, ApprovedRev)
	if !errors.Is(err, core.ErrInvalidPolicy) {
		t.Fatalf("err = %v, want core.ErrInvalidPolicy — a typo that silently does nothing is worse", err)
	}
}

func TestResolveRevPinsTheApprovedHead(t *testing.T) {
	svc, root := newService(t)
	sp := newSpace(t, root, 1)

	head := commitFiles(t, sp, sp.ApprovedBranch(), 1, map[string][]byte{
		"specs/0007-storage.md": doc("SPEC-0007", "Storage", "body"),
	})
	got, err := svc.ResolveRev(context.Background(), sp, ApprovedRev)
	if err != nil {
		t.Fatalf("ResolveRev: %v", err)
	}
	if got != head.String() {
		t.Errorf("ResolveRev = %s, want %s", got, head)
	}
}

func contains(data []byte, want string) bool {
	return strings.Contains(string(data), want)
}