package todo

import (
	"context"
	"fmt"
	"log"

	"entgo.io/ent/dialect"
	_ "github.com/mattn/go-sqlite3"

	"todo/ent"
	"todo/ent/todo"
)

func setup() (context.Context, *ent.Client, func()) {
	client, err := ent.Open(dialect.SQLite, "file:ent?mode=memory&cache=shared&_fk=1")
	if err != nil {
		log.Fatalf("failed opening connection to sqlite: %v", err)
	}
	closer := func() { _ = client.Close() }
	ctx := context.Background()
	// Run the automatic migration tool to create all schema resources
	if err := client.Schema.Create(ctx); err != nil {
		log.Fatalf("failed creating schema resources: %v", err)
	}
	return ctx, client, closer
}

func addTwo(ctx context.Context, client *ent.Client) (*ent.Todo, *ent.Todo) {
	task1, err := client.Todo.Create().SetText("Add GraphQL Example").Save(ctx)
	if err != nil {
		log.Fatalf("failed creating a todo: %v", err)
	}
	task2, err := client.Todo.Create().SetText("Add Tracing Example").Save(ctx)
	if err != nil {
		log.Fatalf("failed creating a todo: %v", err)
	}
	return task1, task2
}

func addTwoConnected(ctx context.Context, client *ent.Client) (*ent.Todo, *ent.Todo) {
	task1, task2 := addTwo(ctx, client)
	if err := task2.Update().SetParent(task1).Exec(ctx); err != nil {
		log.Fatalf("failed connecting todo2 to its parent: %v", err)
	}
	return task1, task2
}

func Example_todo1() {
	_, _, closer := setup()
	defer closer()
	// Output:
}

func Example_todo2() {
	ctx, client, closer := setup()
	defer closer()
	task1, err := client.Todo.Create().SetText(" ").Save(ctx)
	if err != nil {
		log.Fatalf("failed creating a todo: %v", err)
	}
	fmt.Printf("Todo(id=%d)\n", task1.ID)
	// Output:
	// Todo(id=1)
}

func Example_todo3() {
	ctx, client, closer := setup()
	defer closer()
	task1, task2 := addTwo(ctx, client)
	fmt.Printf("%d: %q\n", task1.ID, task1.Text)
	fmt.Printf("%d: %q\n", task2.ID, task2.Text)
	// Output:
	// 1: "Add GraphQL Example"
	// 2: "Add Tracing Example"
}

func Example_todo4() {
	ctx, client, closer := setup()
	defer closer()
	_, _ = addTwoConnected(ctx, client)
	// Output:
}

func Example_todo5() {
	ctx, client, closer := setup()
	defer closer()
	_, _ = addTwoConnected(ctx, client)

	// Query all todo items.
	items, err := client.Todo.Query().All(ctx)
	if err != nil {
		log.Fatalf("failed querying all todos: %v", err)
	}
	for _, item := range items {
		fmt.Printf("%d: %q\n", item.ID, item.Text)
	}
	// Output:
	// 1: "Add GraphQL Example"
	// 2: "Add Tracing Example"
}

func Example_todo6() {
	ctx, client, closer := setup()
	defer closer()
	_, _ = addTwoConnected(ctx, client)

	// Query all todo items that depend on other items
	items, err := client.Todo.Query().Where(todo.HasParent()).All(ctx)
	if err != nil {
		log.Fatalf("failed querying all todos: %v", err)
	}
	for _, item := range items {
		fmt.Printf("%d: %q\n", item.ID, item.Text)
	}
	// Output:
	// 2: "Add Tracing Example"
}

func Example_todo7() {
	ctx, client, closer := setup()
	defer closer()
	_, _ = addTwoConnected(ctx, client)

	// Query all todo items that don't depend on other items and have items that depend on them
	items, err := client.Todo.Query().Where(
		todo.Not(todo.HasParent()),
		todo.HasChildren(),
	).All(ctx)
	if err != nil {
		log.Fatalf("failed querying todos: %v", err)
	}
	for _, item := range items {
		fmt.Printf("%d: %q\n", item.ID, item.Text)
	}
	// Output:
	// 1: "Add GraphQL Example"
}

func Example_todo8() {
	ctx, client, closer := setup()
	defer closer()
	_, _ = addTwoConnected(ctx, client)

	// Query parent through its children
	parent, err := client.Todo.Query().
		Where(todo.HasParent()). // Filter children
		QueryParent().           // Climb to their parent
		Only(ctx)                // Expect exactly one result
	if err != nil {
		log.Fatalf("failed querying todos: %v", err)
	}
	fmt.Printf("%d: %q\n", parent.ID, parent.Text)
	// Output:
	// 1: "Add GraphQL Example"
}