package web

import (
	"context"
	"fmt"
	"net/http"
	"net/url"
	"regexp"
	"strings"
	"testing"

	"sourcecraft.dev/bigbes/sr-ht-ecore/pages"

	"sourcecraft.dev/bigbes/sr-ht-dolt/browse"
	"sourcecraft.dev/bigbes/sr-ht-dolt/core"
)

// dummyView is a test-only View that fingerprints repos containing a table
// named "issues". It renders through the shared error page, which is the one
// page every service's set is guaranteed to carry and the only one that asks
// nothing of the envelope beyond the .Data field every view already has. Its
// Build therefore returns a pages.ErrorData. It records whether Build ran.
type dummyView struct {
	built bool
}

func (d *dummyView) Name() string     { return "issues" }
func (d *dummyView) Label() string    { return "Issues" }
func (d *dummyView) Template() string { return pages.ErrorPage + ".html" }

func (d *dummyView) Applies(tables []browse.TableInfo) bool {
	for _, t := range tables {
		if t.Name == "issues" {
			return true
		}
	}
	return false
}

func (d *dummyView) Build(_ context.Context, sess BrowseSession, _ *core.Repo, ref string, _ url.Values) (any, error) {
	d.built = true
	// Pull data through the BrowseSession surface only, mirroring how a real
	// view works, then hand the page the payload it reads.
	tables, err := sess.Tables(context.Background(), ref)
	if err != nil {
		return nil, err
	}
	return pages.Error(http.StatusOK, fmt.Sprintf("%d tables", len(tables))), nil
}

func issueTables() []browse.TableInfo {
	return []browse.TableInfo{
		{Name: "issues", Columns: []browse.ColumnInfo{{Name: "id", PrimaryKey: true}}, RowCount: 2},
		{Name: "labels", RowCount: 5},
	}
}

func TestApplicableViewsFilters(t *testing.T) {
	v := &dummyView{}
	views := []View{v}

	got := applicableViews(views, issueTables())
	if len(got) != 1 || got[0] != v {
		t.Fatalf("applicableViews should select the matching view; got %v", got)
	}

	// No "issues" table → no applicable views.
	none := applicableViews(views, []browse.TableInfo{{Name: "widgets"}})
	if len(none) != 0 {
		t.Fatalf("applicableViews should filter out non-matching views; got %v", none)
	}
}

func TestApplicableViewsPreservesOrder(t *testing.T) {
	a := &dummyView{}
	// A second always-applies view to check registration order is preserved.
	b := alwaysView{}
	got := applicableViews([]View{b, a}, issueTables())
	if len(got) != 2 || got[0] != View(b) || got[1] != View(a) {
		t.Fatalf("applicableViews should preserve order; got %v", got)
	}
}

// alwaysView is a trivial always-applicable view used to check ordering.
type alwaysView struct{}

func (alwaysView) Name() string                    { return "always" }
func (alwaysView) Label() string                   { return "Always" }
func (alwaysView) Template() string                { return pages.ErrorPage + ".html" }
func (alwaysView) Applies([]browse.TableInfo) bool { return true }
func (alwaysView) Build(context.Context, BrowseSession, *core.Repo, string, url.Values) (any, error) {
	return pages.Error(http.StatusOK, ""), nil
}

func TestHandleViewSelectedAndBuilt(t *testing.T) {
	h := newHarness(t)
	h.store.add(&core.Repo{Name: "db", OwnerID: 1, OwnerName: "alice", Path: "/d", Visibility: core.VisibilityPublic})
	h.browse.sess = &fakeSession{
		branches: []browse.Branch{{Name: "main", Head: "abcdef1234567890"}},
		tables:   issueTables(),
	}

	dv := &dummyView{}
	// Inject the view directly on the app, without polluting the global registry.
	setViews(t, h, dv)

	rec := h.do("GET", "/~alice/db/view/issues", nil, nil)
	// A 200 (rather than the 404 an unknown/non-applicable view returns) proves
	// the view was selected and its Template rendered; dv.built proves Build ran.
	if rec.Code != http.StatusOK {
		t.Fatalf("view page: got %d, want 200; body=%s", rec.Code, rec.Body.String())
	}
	if !dv.built {
		t.Fatalf("view.Build was not called")
	}
	// The view's Label flows into the page <title> via the envelope's basePage,
	// so its presence confirms this view (not a fallback) produced the response.
	if !strings.Contains(rec.Body.String(), "Issues") {
		t.Fatalf("view page missing view label in chrome; body=%s", rec.Body.String())
	}
}

func TestHandleViewUnknownSlugIs404(t *testing.T) {
	h := newHarness(t)
	h.store.add(&core.Repo{Name: "db", OwnerID: 1, OwnerName: "alice", Path: "/d", Visibility: core.VisibilityPublic})
	h.browse.sess = &fakeSession{
		branches: []browse.Branch{{Name: "main", Head: "abcdef1234567890"}},
		tables:   issueTables(),
	}
	setViews(t, h, &dummyView{})

	rec := h.do("GET", "/~alice/db/view/nope", nil, nil)
	if rec.Code != http.StatusNotFound {
		t.Fatalf("unknown view slug: got %d, want 404", rec.Code)
	}
}

func TestHandleViewNotApplicableIs404(t *testing.T) {
	h := newHarness(t)
	h.store.add(&core.Repo{Name: "db", OwnerID: 1, OwnerName: "alice", Path: "/d", Visibility: core.VisibilityPublic})
	// Tables lack "issues", so dummyView.Applies is false even though the slug matches.
	h.browse.sess = &fakeSession{
		branches: []browse.Branch{{Name: "main", Head: "abcdef1234567890"}},
		tables:   []browse.TableInfo{{Name: "widgets"}},
	}
	setViews(t, h, &dummyView{})

	rec := h.do("GET", "/~alice/db/view/issues", nil, nil)
	if rec.Code != http.StatusNotFound {
		t.Fatalf("non-applicable view: got %d, want 404", rec.Code)
	}
}

func TestOverviewShowsViewTabs(t *testing.T) {
	h := newHarness(t)
	h.store.add(&core.Repo{Name: "db", OwnerID: 1, OwnerName: "alice", Path: "/d", Visibility: core.VisibilityPublic})
	h.browse.sess = &fakeSession{
		branches: []browse.Branch{{Name: "main", Head: "abcdef1234567890"}},
		tables:   issueTables(),
	}
	setViews(t, h, &dummyView{})

	rec := h.do("GET", "/~alice/db", nil, nil)
	if rec.Code != http.StatusOK {
		t.Fatalf("overview: got %d, want 200", rec.Code)
	}
	body := rec.Body.String()
	if !strings.Contains(body, "/~alice/db/view/issues") {
		t.Fatalf("overview missing view tab link; body=%s", body)
	}
	if !strings.Contains(body, "nav-tabs") {
		t.Fatalf("overview missing tab bar; body=%s", body)
	}
	// The bar carries three tabs in order: Overview, Tables, then the view.
	iOverview := strings.Index(body, ">Overview<")
	iTables := strings.Index(body, ">Tables<")
	iView := strings.Index(body, "/~alice/db/view/issues")
	if iOverview < 0 || iTables < 0 {
		t.Fatalf("overview missing Overview/Tables tabs; body=%s", body)
	}
	if !(iOverview < iTables && iTables < iView) {
		t.Fatalf("tab order should be Overview < Tables < view; got %d, %d, %d", iOverview, iTables, iView)
	}
	// The active tab on the overview is Overview, not Tables.
	if !regexp.MustCompile(`nav-link active"[^>]*>Overview<`).MatchString(body) {
		t.Fatalf("overview tab should be active on the overview page; body=%s", body)
	}
}

// setViews overrides the app's view snapshot without touching the global
// registry, so view routing/overview tabs can be exercised with a controlled
// set. The harness retains the *app the router is mounted on.
func setViews(t *testing.T, h *harness, vs ...View) {
	t.Helper()
	h.app.views = vs
}