package deadlinks

import (
	"context"
	"fmt"
	"sort"
	"testing"
	"time"

	"code.betamike.com/mediocregopher/mediocre-go-lib/miter"
	"github.com/stretchr/testify/assert"
)

type sqliteStoreHarness struct {
	ctx   context.Context
	now   time.Time
	store *SQLiteStore
}

func newSQLiteStoreHarness() *sqliteStoreHarness {
	var (
		ctx   = context.Background()
		now   = time.Now().Truncate(time.Second).UTC()
		store = NewSQLiteStore(nil)
	)

	return &sqliteStoreHarness{
		ctx, now, store,
	}
}

func (h *sqliteStoreHarness) assertGetByStatus(
	t *testing.T, want []Resource, status ResourceStatus,
) {
	norm := func(rr []Resource) {
		for i, r := range rr {
			sort.Slice(r.IncomingLinkURLs, func(i, j int) bool {
				return r.IncomingLinkURLs[i] < r.IncomingLinkURLs[j]
			})
			sort.Slice(r.OutgoingLinkURLs, func(i, j int) bool {
				return r.OutgoingLinkURLs[i] < r.OutgoingLinkURLs[j]
			})
			rr[i] = r
		}

		sort.Slice(rr, func(i, j int) bool {
			return rr[i].URL < rr[j].URL
		})
	}

	got, err := miter.ToSlice(h.ctx, h.store.GetByStatus(status))
	assert.NoError(t, err)

	norm(want)
	norm(got)
	assert.Equal(t, want, got)
}

func TestSQLiteStore(t *testing.T) {
	t.Parallel()

	t.Run("SetPinned", func(t *testing.T) {
		t.Parallel()

		var (
			h    = newSQLiteStoreHarness()
			urlA = URL("https://a.com")
			urlB = URL("https://b.com")
			a    = Resource{URL: urlA, Pinned: true}
			b    = Resource{URL: urlB, Pinned: true}
		)

		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlA}))
		h.assertGetByStatus(t, nil, ResourceStatusOK)
		h.assertGetByStatus(t, []Resource{a}, ResourceStatusUnknown)

		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlA, urlB}))
		h.assertGetByStatus(t, nil, ResourceStatusOK)
		h.assertGetByStatus(t, []Resource{a, b}, ResourceStatusUnknown)

		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlB}))
		h.assertGetByStatus(t, nil, ResourceStatusOK)
		// GetByStatus should not return resources which are not pinned and have
		// no incoming links
		h.assertGetByStatus(t, []Resource{b}, ResourceStatusUnknown)
	})

	t.Run("Update/general", func(t *testing.T) {
		t.Parallel()

		var (
			h = newSQLiteStoreHarness()

			urlA = URL("https://a.com")
			urlB = URL("https://b.com")
			urlC = URL("https://c.com")

			a = Resource{URL: urlA, Pinned: true}
			b = Resource{URL: urlB, Pinned: true}
			c = Resource{URL: urlC}
		)

		// updating a non-existing URL should fail and make no changes
		assert.Error(t, h.store.Update(h.ctx, h.now, urlA, ResourceStatusOK, "errstr", nil))
		h.assertGetByStatus(t, nil, ResourceStatusUnknown)
		h.assertGetByStatus(t, nil, ResourceStatusOK)

		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlA, urlB}))

		assert.NoError(t, h.store.Update(h.ctx, h.now, urlA, ResourceStatusOK, "", nil))
		a.LastChecked = h.now
		a.Status = ResourceStatusOK
		h.assertGetByStatus(t, []Resource{b}, ResourceStatusUnknown)
		h.assertGetByStatus(t, []Resource{a}, ResourceStatusOK)

		assert.NoError(t, h.store.Update(h.ctx, h.now, urlB, ResourceStatusError, "error!", nil))
		b.LastChecked = h.now
		b.Status = ResourceStatusError
		b.ErrorString = "error!"
		h.assertGetByStatus(t, nil, ResourceStatusUnknown)
		h.assertGetByStatus(t, nil, ResourceStatusUnknown)
		h.assertGetByStatus(t, []Resource{a}, ResourceStatusOK)
		h.assertGetByStatus(t, []Resource{b}, ResourceStatusError)

		assert.NoError(t, h.store.Update(
			h.ctx, h.now, urlA, ResourceStatusOK, "", []URL{urlC},
		))
		a.OutgoingLinkURLs = []URL{urlC}
		c.IncomingLinkURLs = []URL{urlA}
		h.assertGetByStatus(t, []Resource{c}, ResourceStatusUnknown)
		h.assertGetByStatus(t, []Resource{a}, ResourceStatusOK)
		h.assertGetByStatus(t, []Resource{b}, ResourceStatusError)

		assert.NoError(t, h.store.Update(
			h.ctx, h.now, urlB, ResourceStatusOK, "", []URL{urlC},
		))
		b.Status = ResourceStatusOK
		b.ErrorString = ""
		b.OutgoingLinkURLs = []URL{urlC}
		c.IncomingLinkURLs = []URL{urlA, urlB}
		h.assertGetByStatus(t, []Resource{c}, ResourceStatusUnknown)
		h.assertGetByStatus(t, []Resource{a, b}, ResourceStatusOK)
		h.assertGetByStatus(t, nil, ResourceStatusError)
	})

	t.Run("Update/while_GetByStatus", func(t *testing.T) {
		t.Parallel()

		var (
			h = newSQLiteStoreHarness()

			urlA = URL("https://a.com")
			urlB = URL("https://b.com")
			urlC = URL("https://c.com")

			a = Resource{
				URL:              urlA,
				Status:           ResourceStatusOK,
				Pinned:           true,
				LastChecked:      h.now,
				OutgoingLinkURLs: []URL{urlC},
			}

			b = Resource{
				URL:              urlB,
				Status:           ResourceStatusOK,
				Pinned:           true,
				LastChecked:      h.now,
				OutgoingLinkURLs: []URL{urlC},
			}

			c = Resource{
				URL:              urlC,
				Status:           ResourceStatusOK,
				LastChecked:      h.now,
				IncomingLinkURLs: []URL{urlA, urlB, urlC},
				OutgoingLinkURLs: []URL{urlC},
			}
		)

		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlA, urlB}))

		iter := h.store.GetByStatus(ResourceStatusUnknown)
		err := miter.ForEach(h.ctx, iter, func(r Resource) error {
			err := h.store.Update(
				h.ctx, h.now, r.URL, ResourceStatusOK, "", []URL{urlC},
			)

			if err != nil {
				return fmt.Errorf("updating %+v: %w", r, err)
			}
			return nil
		})
		assert.NoError(t, err)

		h.assertGetByStatus(t, []Resource{a, b, c}, ResourceStatusOK)
	})

	t.Run("GetURLsByLastChecked", func(t *testing.T) {
		t.Parallel()

		var (
			h    = newSQLiteStoreHarness()
			nowA = h.now
			nowB = h.now.Add(1 * time.Minute)

			urlA = URL("https://a.com")
			urlB = URL("https://b.com")
			urlC = URL("https://c.com")
		)

		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlA, urlB, urlC}))

		assert.NoError(t, h.store.Update(
			h.ctx, nowA, urlA, ResourceStatusOK, "", nil,
		))

		assert.NoError(t, h.store.Update(
			h.ctx, nowB, urlB, ResourceStatusOK, "", nil,
		))

		assertGetURLsByLastChecked := func(want []URL, olderThan time.Time) {
			got, err := miter.ToSlice(h.ctx, h.store.GetURLsByLastChecked(olderThan))
			assert.NoError(t, err)
			assert.ElementsMatch(t, want, got)
		}

		assertGetURLsByLastChecked([]URL{urlA, urlB, urlC}, nowB.Add(1*time.Second))
		assertGetURLsByLastChecked([]URL{urlA, urlC}, nowB)
		assertGetURLsByLastChecked([]URL{urlA, urlC}, nowA.Add(1*time.Second))
		assertGetURLsByLastChecked([]URL{urlC}, nowA)

		// A Resource which is not pinned and has no incoming links should not
		// be returned
		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlA, urlB}))
		assertGetURLsByLastChecked([]URL{urlA, urlB}, nowB.Add(1*time.Second))
		assertGetURLsByLastChecked([]URL{}, nowA)
	})

	t.Run("GC", func(t *testing.T) {
		t.Parallel()

		var (
			h = newSQLiteStoreHarness()

			urlA = URL("https://a.com")
			urlB = URL("https://b.com")
			urlC = URL("https://c.com")
			urlD = URL("https://d.com")

			a = Resource{URL: urlA, Pinned: true, LastChecked: h.now, OutgoingLinkURLs: []URL{urlB}}
			b = Resource{URL: urlB, IncomingLinkURLs: []URL{urlA}}
		)

		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlA, urlB, urlC, urlD}))
		assert.NoError(t, h.store.SetPinned(h.ctx, []URL{urlA}))

		assert.NoError(t, h.store.Update(
			h.ctx, h.now, urlA, ResourceStatusUnknown, "", []URL{urlB},
		))

		assert.NoError(t, h.store.Update(
			h.ctx, h.now, urlC, ResourceStatusUnknown, "", []URL{urlD},
		))

		assert.NoError(t, h.store.GC(h.ctx))
		h.assertGetByStatus(t, []Resource{a, b}, ResourceStatusUnknown)

		// Calling again shouldn't do anything
		assert.NoError(t, h.store.GC(h.ctx))
		h.assertGetByStatus(t, []Resource{a, b}, ResourceStatusUnknown)
	})
}