package vidser

import (
	"errors"
	"fmt"
	"testing"
	"time"

	"91porn-server/common/stderr"

	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo"
)

func TestDecideFreeWatchConsume(t *testing.T) {
	tests := []struct {
		name          string
		state         freeWatchConsumeState
		wantCan       bool
		wantConsume   bool
		wantRemaining uint64
	}{
		{
			name:          "eligible video consumes",
			state:         freeWatchConsumeState{watchCount: 3, totalCount: 3},
			wantCan:       true,
			wantConsume:   true,
			wantRemaining: 3,
		},
		{
			name:          "already viewed is idempotent",
			state:         freeWatchConsumeState{viewedToday: true, watchCount: 2, totalCount: 3},
			wantCan:       true,
			wantRemaining: 2,
		},
		{
			name:          "vip does not consume",
			state:         freeWatchConsumeState{isVIP: true, watchCount: 2, totalCount: 3},
			wantCan:       true,
			wantRemaining: 2,
		},
		{
			name:          "publisher does not consume",
			state:         freeWatchConsumeState{isPublisher: true, watchCount: 2, totalCount: 3},
			wantCan:       true,
			wantRemaining: 2,
		},
		{
			name:          "free area does not consume",
			state:         freeWatchConsumeState{freeArea: true, watchCount: 2, totalCount: 3},
			wantCan:       true,
			wantRemaining: 2,
		},
		{
			name:          "coin video does not consume",
			state:         freeWatchConsumeState{paidVideo: true, watchCount: 2, totalCount: 3},
			wantCan:       true,
			wantRemaining: 2,
		},
		{
			name:    "no remaining count denies new video",
			state:   freeWatchConsumeState{watchCount: 0, totalCount: 3},
			wantCan: false,
		},
		{
			name:          "count is clamped to configured total",
			state:         freeWatchConsumeState{watchCount: 8, totalCount: 3},
			wantCan:       true,
			wantConsume:   true,
			wantRemaining: 3,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := decideFreeWatchConsume(tt.state)
			if got.isCan != tt.wantCan || got.shouldConsume != tt.wantConsume || got.watchCount != tt.wantRemaining {
				t.Fatalf("decision = %+v, want isCan=%v shouldConsume=%v watchCount=%d",
					got, tt.wantCan, tt.wantConsume, tt.wantRemaining)
			}
		})
	}
}

func TestFreeWatchConsumeKeyScope(t *testing.T) {
	oid := primitive.NewObjectID()
	day := time.Date(2026, 7, 28, 0, 0, 0, 0, time.Local)
	key := freeWatchConsumeKey(1001, oid, day)
	if key != freeWatchConsumeKey(1001, oid, day) {
		t.Fatal("same user, video and day must produce the same consume key")
	}
	if key == freeWatchConsumeKey(1002, oid, day) {
		t.Fatal("consume key must be scoped by user")
	}
	if key == freeWatchConsumeKey(1001, primitive.NewObjectID(), day) {
		t.Fatal("consume key must be scoped by video")
	}
	if key == freeWatchConsumeKey(1001, oid, day.AddDate(0, 0, 1)) {
		t.Fatal("consume key must be scoped by day")
	}
}

func TestIsRetryableFreeWatchTransactionError(t *testing.T) {
	tests := []struct {
		name string
		err  error
		want bool
	}{
		{
			name: "wrapped transient label",
			err: fmt.Errorf("decrement watch count: %w", mongo.CommandError{
				Code:   112,
				Labels: []string{"TransientTransactionError"},
			}),
			want: true,
		},
		{
			name: "write conflict code",
			err:  mongo.CommandError{Code: 112},
			want: true,
		},
		{
			name: "write exception transient label",
			err: mongo.WriteException{
				Labels: []string{"TransientTransactionError"},
			},
			want: true,
		},
		{
			name: "no such transaction code",
			err:  fmt.Errorf("retry transaction: %w", mongo.CommandError{Code: 251}),
			want: true,
		},
		{
			name: "ordinary database error",
			err:  errors.New("database unavailable"),
		},
		{
			name: "nil",
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := isRetryableFreeWatchTransactionError(tt.err); got != tt.want {
				t.Fatalf("isRetryableFreeWatchTransactionError() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestRunFreeWatchTransactionWithRetry(t *testing.T) {
	transient := fmt.Errorf("wrapped write conflict: %w", mongo.CommandError{
		Code:   112,
		Labels: []string{"TransientTransactionError"},
	})

	t.Run("eventually succeeds", func(t *testing.T) {
		calls := 0
		err := runFreeWatchTransactionWithRetry(func() error {
			calls++
			if calls < 3 {
				return transient
			}
			return nil
		})
		if err != nil || calls != 3 {
			t.Fatalf("err = %v, calls = %d, want nil and 3 calls", err, calls)
		}
	})

	t.Run("stops at retry limit", func(t *testing.T) {
		calls := 0
		err := runFreeWatchTransactionWithRetry(func() error {
			calls++
			return transient
		})
		if err == nil || calls != freeWatchTransactionRetryLimit {
			t.Fatalf("err = %v, calls = %d, want error and %d calls",
				err, calls, freeWatchTransactionRetryLimit)
		}
	})

	t.Run("duplicate is handled by caller without retry", func(t *testing.T) {
		calls := 0
		err := runFreeWatchTransactionWithRetry(func() error {
			calls++
			return stderr.InsertExistError
		})
		if !stderr.IsEqual(err, stderr.InsertExistError) || calls != 1 {
			t.Fatalf("err = %v, calls = %d, want duplicate and 1 call", err, calls)
		}
	})

	t.Run("ordinary error is not retried", func(t *testing.T) {
		calls := 0
		ordinary := errors.New("database unavailable")
		err := runFreeWatchTransactionWithRetry(func() error {
			calls++
			return ordinary
		})
		if !errors.Is(err, ordinary) || calls != 1 {
			t.Fatalf("err = %v, calls = %d, want ordinary error and 1 call", err, calls)
		}
	})
}