t = db["jstests_coveredIndex1"];
t.drop();

// Include helpers for analyzing explain output.
load("jstests/libs/analyze_plan.js");

t.save({fn: "john", ln: "doe"});
t.save({fn: "jack", ln: "doe"});
t.save({fn: "john", ln: "smith"});
t.save({fn: "jack", ln: "black"});
t.save({fn: "bob", ln: "murray"});
t.save({fn: "aaa", ln: "bbb", obj: {a: 1, b: "blah"}});
assert.eq(t.findOne({ln: "doe"}).fn, "john", "Cannot find right record");
assert.eq(t.count(), 6, "Not right length");

// use simple index
t.ensureIndex({ln: 1});
assert(!isIndexOnly(t.find({ln: "doe"}).explain().queryPlanner.winningPlan),
       "Find using covered index but all fields are returned");
assert(!isIndexOnly(t.find({ln: "doe"}, {ln: 1}).explain().queryPlanner.winningPlan),
       "Find using covered index but _id is returned");
assert(isIndexOnly(t.find({ln: "doe"}, {ln: 1, _id: 0}).explain().queryPlanner.winningPlan),
       "Find is not using covered index");

// this time, without a query spec
// SERVER-2109
// assert.eq( t.find({}, {ln: 1, _id: 0}).explain().indexOnly, true, "Find is not using covered
// index");
assert(isIndexOnly(t.find({}, {ln: 1, _id: 0}).hint({ln: 1}).explain().queryPlanner.winningPlan),
       "Find is not using covered index");

// use compound index
t.dropIndex({ln: 1});
t.ensureIndex({ln: 1, fn: 1});
// return 1 field
var plan = t.find({ln: "doe"}, {ln: 1, _id: 0}).explain();
assert(isIndexOnly(plan.queryPlanner.winningPlan), "Find is not using covered index");
// return both fields, multiple docs returned
var plan = t.find({ln: "doe"}, {ln: 1, fn: 1, _id: 0}).explain();
assert(isIndexOnly(plan.queryPlanner.winningPlan), "Find is not using covered index");
// match 1 record using both fields
var plan = t.find({ln: "doe", fn: "john"}, {ln: 1, fn: 1, _id: 0}).explain();
assert(isIndexOnly(plan.queryPlanner.winningPlan), "Find is not using covered index");
// change ordering
var plan = t.find({fn: "john", ln: "doe"}, {fn: 1, ln: 1, _id: 0}).explain();
assert(isIndexOnly(plan.queryPlanner.winningPlan), "Find is not using covered index");
// ask from 2nd index key
var plan = t.find({fn: "john"}, {fn: 1, _id: 0}).explain();
assert(!isIndexOnly(plan.queryPlanner.winningPlan),
       "Find is using covered index, but doesnt have 1st key");

// repeat above but with _id field
t.dropIndex({ln: 1, fn: 1});
t.ensureIndex({_id: 1, ln: 1});
// return 1 field
var plan = t.find({_id: 123, ln: "doe"}, {_id: 1}).explain();
assert(isIndexOnly(plan.queryPlanner.winningPlan), "Find is not using covered index");
// match 1 record using both fields
var plan = t.find({_id: 123, ln: "doe"}, {ln: 1}).explain();
assert(isIndexOnly(plan.queryPlanner.winningPlan), "Find is not using covered index");
// change ordering
var plan = t.find({ln: "doe", _id: 123}, {ln: 1, _id: 1}).explain();
assert(isIndexOnly(plan.queryPlanner.winningPlan), "Find is not using covered index");
// ask from 2nd index key
var plan = t.find({ln: "doe"}, {ln: 1}).explain();
assert(!isIndexOnly(plan.queryPlanner.winningPlan),
       "Find is using covered index, but doesnt have 1st key");

// repeat above but with embedded obj
t.dropIndex({_id: 1, ln: 1});
t.ensureIndex({obj: 1});
var plan = t.find({"obj.a": 1}, {obj: 1}).explain();
assert(!isIndexOnly(plan.queryPlanner.winningPlan), "Shouldnt use index when introspecting object");
var plan = t.find({obj: {a: 1, b: "blah"}}).explain();
assert(!isIndexOnly(plan.queryPlanner.winningPlan), "Index doesnt have all fields to cover");
var plan = t.find({obj: {a: 1, b: "blah"}}, {obj: 1, _id: 0}).explain();
assert(isIndexOnly(plan.queryPlanner.winningPlan), "Find is not using covered index");

// repeat above but with index on sub obj field
t.dropIndex({obj: 1});
t.ensureIndex({"obj.a": 1, "obj.b": 1});
var plan = t.find({"obj.a": 1}, {obj: 1}).explain();
assert(!isIndexOnly(plan.queryPlanner.winningPlan), "Shouldnt use index when introspecting object");

assert(t.validate().valid);