// Copyright 2018 The CUE Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package cue_test

import (
	"fmt"
	"testing"

	"cuelang.org/go/cue"
	"cuelang.org/go/cue/build"
	"cuelang.org/go/cue/token"

	_ "cuelang.org/go/pkg"
)

func TestBuiltins(t *testing.T) {
	test := func(pkg, expr string) []*bimport {
		return []*bimport{{"",
			[]string{fmt.Sprintf("import %q\n(%s)", pkg, expr)},
		}}
	}
	testExpr := func(expr string) []*bimport {
		return []*bimport{{"",
			[]string{fmt.Sprintf("(%s)", expr)},
		}}
	}
	testCases := []struct {
		instances []*bimport
		emit      string
	}{{
		test("math", "math.Pi"),
		`3.14159265358979323846264338327950288419716939937510582097494459`,
	}, {
		test("math", "math.Floor(math.Pi)"),
		`3`,
	}, {
		test("math", "math.Pi(3)"),
		`_|_(cannot call non-function math.Pi (type float))`,
	}, {
		test("math", "math.Floor(3, 5)"),
		`_|_(too many arguments in call to math.Floor (have 2, want 1))`,
	}, {
		test("math", `math.Floor("foo")`),
		`_|_(cannot use "foo" (type string) as number in argument 1 to math.Floor)`,
	}, {
		test("crypto/sha256", `sha256.Sum256("hash me")`),
		`'\xeb \x1a\xf5\xaa\xf0\xd6\x06)\xd3Ҧ\x1eFl\xfc\x0f\xed\xb5\x17\xad\xd81\xec\xacR5\xe1کc\xd6'`,
	}, {
		test("crypto/md5", `len(md5.Sum("hash me"))`),
		`16`,
	}, {
		test("encoding/yaml", `yaml.Validate("a: 2\n---\na: 4", {a:<3})`),
		`_|_(error in call to encoding/yaml.Validate: a: invalid value 4 (out of bound <3))`,
	}, {
		test("encoding/yaml", `yaml.Validate("a: 2\n---\na: 4", {a:<5})`),
		`true`,
	}, {
		test("encoding/yaml", `yaml.Validate("a: 2\n", {a:<5, b:int})`),
		`_|_(error in call to encoding/yaml.Validate: b: incomplete value int)`,
	}, {
		test("strconv", `strconv.FormatUint(64, 16)`),
		`"40"`,
	}, {
		test("regexp", `regexp.Find(#"f\w\w"#, "afoot")`),
		`"foo"`,
	}, {
		test("regexp", `regexp.Find(#"f\w\w"#, "bar")`),
		`_|_(error in call to regexp.Find: no match)`,
	}, {
		testExpr(`len([1, 2, 3])`),
		`3`,
	}, {
		testExpr(`len("foo")`),
		`3`,
	}, {
		test("encoding/json", `json.MarshalStream([{a: 1}, {b: 2}])`),
		`"{\"a\":1}\n{\"b\":2}\n"`,
	}, {
		test("encoding/json", `{
			x: int
			y: json.Marshal({a: x})
		}`),
		`{x:int,y:_|_(cannot convert incomplete value "int" to JSON)}`,
	}, {
		test("encoding/yaml", `yaml.MarshalStream([{a: 1}, {b: 2}])`),
		`"a: 1\n---\nb: 2\n"`,
	}, {
		test("struct", `struct.MinFields(0) & ""`),
		`_|_(conflicting values struct.MinFields(0) and "" (mismatched types struct and string))`,
	}, {
		test("struct", `struct.MinFields(0) & {a: 1}`),
		`{a:1}`,
	}, {
		test("struct", `struct.MinFields(2) & {a: 1}`),
		// TODO: original value may be better.
		// `_|_(invalid value {a:1} (does not satisfy struct.MinFields(2)))`,
		`_|_(invalid value {a:1} (does not satisfy struct.MinFields(2)): len(fields) < MinFields(2) (1 < 2))`,
	}, {
		test("time", `time.Time & "1937-01-01T12:00:27.87+00:20"`),
		`"1937-01-01T12:00:27.87+00:20"`,
	}, {
		test("time", `time.Time & "no time"`),
		`_|_(invalid value "no time" (does not satisfy time.Time): error in call to time.Time: invalid time "no time")`,
	}, {
		test("time", `time.Unix(1500000000, 123456)`),
		`"2017-07-14T02:40:00.000123456Z"`,
	}}
	for i, tc := range testCases {
		t.Run(fmt.Sprint(i), func(t *testing.T) {
			insts := cue.Build(makeInstances(tc.instances))
			if err := insts[0].Err; err != nil {
				t.Fatal(err)
			}
			v := insts[0].Value()
			got := fmt.Sprintf("%+v", v)
			if got != tc.emit {
				t.Errorf("\n got: %s\nwant: %s", got, tc.emit)
			}
		})
	}
}

// For debugging purposes. Do not remove.
func TestSingleBuiltin(t *testing.T) {
	t.Skip("error message")

	test := func(pkg, expr string) []*bimport {
		return []*bimport{{"",
			[]string{fmt.Sprintf("import %q\n(%s)", pkg, expr)},
		}}
	}
	testCases := []struct {
		instances []*bimport
		emit      string
	}{{
		test("list", `list.Sort([{a:1}, {b:2}], list.Ascending)`),
		`_|_(error in call to list.Sort: less: invalid operands {b:2} and {a:1} to '<' (type struct and struct))`,
	}}
	for i, tc := range testCases {
		t.Run(fmt.Sprint(i), func(t *testing.T) {
			insts := cue.Build(makeInstances(tc.instances))
			if err := insts[0].Err; err != nil {
				t.Fatal(err)
			}
			v := insts[0].Value()
			got := fmt.Sprint(v)
			if got != tc.emit {
				t.Errorf("\n got: %s\nwant: %s", got, tc.emit)
			}
		})
	}
}

type builder struct {
	ctxt    *build.Context
	imports map[string]*bimport
}

func (b *builder) load(pos token.Pos, path string) *build.Instance {
	bi := b.imports[path]
	if bi == nil {
		return nil
	}
	return b.build(bi)
}

type bimport struct {
	path  string // "" means top-level
	files []string
}

func makeInstances(insts []*bimport) (instances []*build.Instance) {
	b := builder{
		ctxt:    build.NewContext(),
		imports: map[string]*bimport{},
	}
	for _, bi := range insts {
		if bi.path != "" {
			b.imports[bi.path] = bi
		}
	}
	for _, bi := range insts {
		if bi.path == "" {
			instances = append(instances, b.build(bi))
		}
	}
	return
}

func (b *builder) build(bi *bimport) *build.Instance {
	path := bi.path
	if path == "" {
		path = "dir"
	}
	p := b.ctxt.NewInstance(path, b.load)
	for i, f := range bi.files {
		_ = p.AddFile(fmt.Sprintf("file%d.cue", i), f)
	}
	_ = p.Complete()
	return p
}