// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: MIT

package interpres

import (
	"slices"
	"strings"
	"testing"
)

// mustEntry returns the entry a table must have, and fails the test when it
// does not.
func mustEntry(t *testing.T, tbl *Table, key string) *Entry {
	t.Helper()
	e, ok := tbl.Get(key)
	if !ok {
		t.Fatalf("%q is missing from the table", key)
	}
	return e
}

func TestDocumentKeepsKeyOrder(t *testing.T) {
	doc, err := Parse([]byte(`
b = 1
a = 2
inline = {y = 1, x = 2}

[table]
z = 3
m = 4
`))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}

	// The root's keys come back in written order, not sorted.
	if got := doc.Root().Keys(); !slices.Equal(got, []string{"b", "a", "inline", "table"}) {
		t.Errorf("root keys = %v, want [b a inline table]", got)
	}

	// So do the keys of an inline table, which the map shape loses.
	inline, ok := doc.Root().Get("inline")
	if !ok {
		t.Fatal("inline is missing from the root")
	}
	if !inline.Inline() {
		t.Error("inline is not marked inline")
	}
	if got := inline.Table().Keys(); !slices.Equal(got, []string{"y", "x"}) {
		t.Errorf("inline keys = %v, want [y x]", got)
	}

	// And the keys of a table written under a header, which is not inline.
	tbl, ok := doc.Root().Get("table")
	if !ok {
		t.Fatal("table is missing from the root")
	}
	if tbl.Inline() {
		t.Error("table is marked inline")
	}
	if got := tbl.Table().Keys(); !slices.Equal(got, []string{"z", "m"}) {
		t.Errorf("table keys = %v, want [z m]", got)
	}
}

func TestDocumentValuesAreTheTree(t *testing.T) {
	doc, err := Parse([]byte("n = 7\ns = \"x\"\n\n[t]\nk = true\n"))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if got := mustEntry(t, doc.Root(), "n").Value(); got != int64(7) {
		t.Errorf("n = %#v, want int64(7)", got)
	}
	tbl := mustEntry(t, doc.Root(), "t").Table()
	if got := mustEntry(t, tbl, "k").Value(); got != true {
		t.Errorf("t.k = %#v, want true", got)
	}
	// Map gives the tree ParseMap would have returned, the same values.
	tree := doc.Map()
	if tree["n"] != int64(7) || tree["s"] != "x" {
		t.Errorf("Map = %#v", tree)
	}
	if tree["t"].(map[string]any)["k"] != true {
		t.Errorf("Map[t] = %#v", tree["t"])
	}
	if tbl.Values()["k"] != true {
		t.Errorf("t.Values() = %#v", tbl.Values())
	}
}

func TestDocumentComments(t *testing.T) {
	doc, err := Parse([]byte(`# above b
b = 1 # trailing b

# above the table
[table] # trailing table
# above m
m = 2

# footer
`))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}

	b, ok := doc.Root().Get("b")
	if !ok {
		t.Fatal("b is missing")
	}
	if got := b.Comments(); !slices.Equal(got, []string{"above b"}) {
		t.Errorf("b comments = %q, want [above b]", got)
	}
	if got := b.Trailing(); got != "trailing b" {
		t.Errorf("b trailing = %q, want \"trailing b\"", got)
	}

	tbl, ok := doc.Root().Get("table")
	if !ok {
		t.Fatal("table is missing")
	}
	// A [header] line introduces the table, so the comments around it belong
	// to the table node; the entry that names it stays bare.
	if got := tbl.Table().Comments(); !slices.Equal(got, []string{"above the table"}) {
		t.Errorf("table comments = %q, want [above the table]", got)
	}
	if got := tbl.Table().Trailing(); got != "trailing table" {
		t.Errorf("table trailing = %q, want \"trailing table\"", got)
	}
	if got := tbl.Comments(); got != nil {
		t.Errorf("entry comments = %q, want none", got)
	}
	m, ok := tbl.Table().Get("m")
	if !ok {
		t.Fatal("table.m is missing")
	}
	if got := m.Comments(); !slices.Equal(got, []string{"above m"}) {
		t.Errorf("m comments = %q, want [above m]", got)
	}

	if got := doc.Footer(); !slices.Equal(got, []string{"footer"}) {
		t.Errorf("footer = %q, want [footer]", got)
	}
}

func TestDocumentCommentsAreWritable(t *testing.T) {
	doc, err := Parse([]byte("# above\nk = 1\n"))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	entry, ok := doc.Root().Get("k")
	if !ok {
		t.Fatal("k is missing")
	}
	entry.SetComments([]string{"first", "second"})
	entry.SetTrailing("beside")
	if got := entry.Comments(); !slices.Equal(got, []string{"first", "second"}) {
		t.Errorf("comments = %q", got)
	}
	if got := entry.Trailing(); got != "beside" {
		t.Errorf("trailing = %q", got)
	}

	tbl := doc.Root()
	tbl.SetComments([]string{"above the root"})
	if got := tbl.Comments(); !slices.Equal(got, []string{"above the root"}) {
		t.Errorf("root comments = %q", got)
	}
	doc.SetFooter([]string{"end"})
	if got := doc.Footer(); !slices.Equal(got, []string{"end"}) {
		t.Errorf("footer = %q", got)
	}
}

func TestDocumentArrayOfTables(t *testing.T) {
	doc, err := Parse([]byte(`# first element
[[item]]
a = 1

[[item]]
b = 2 # beside b
`))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	entry, ok := doc.Root().Get("item")
	if !ok {
		t.Fatal("item is missing")
	}
	elems := entry.Elements()
	if len(elems) != 2 {
		t.Fatalf("elements = %d, want 2", len(elems))
	}
	if got := elems[0].Keys(); !slices.Equal(got, []string{"a"}) {
		t.Errorf("first element keys = %v, want [a]", got)
	}
	if got := elems[0].Comments(); !slices.Equal(got, []string{"first element"}) {
		t.Errorf("first element comments = %q", got)
	}
	if got := elems[1].Keys(); !slices.Equal(got, []string{"b"}) {
		t.Errorf("second element keys = %v, want [b]", got)
	}
	if got := mustEntry(t, elems[1], "b").Trailing(); got != "beside b" {
		t.Errorf("b trailing = %q, want \"beside b\"", got)
	}
	// The value keeps the map shape the decoder reads.
	if _, ok := entry.Value().([]map[string]any); !ok {
		t.Errorf("item value = %#v, want []map[string]any", entry.Value())
	}
}

func TestDocumentDottedKeysAndValueArrays(t *testing.T) {
	doc, err := Parse([]byte("a.b.c = 1\narr = [1, {x = 1}]\n"))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}

	// A dotted key builds tables, and they are not inline ones.
	a, ok := doc.Root().Get("a")
	if !ok {
		t.Fatal("a is missing")
	}
	if a.Inline() {
		t.Error("a is marked inline")
	}
	b, ok := a.Table().Get("b")
	if !ok {
		t.Fatal("a.b is missing")
	}
	if b.Inline() {
		t.Error("a.b is marked inline")
	}
	if got := b.Table().Keys(); !slices.Equal(got, []string{"c"}) {
		t.Errorf("a.b keys = %v, want [c]", got)
	}

	// An inline table inside a value array keeps its node in the elements
	// slice; the scalar before it has none.
	arr, ok := doc.Root().Get("arr")
	if !ok {
		t.Fatal("arr is missing")
	}
	elems := arr.Elements()
	if len(elems) != 2 {
		t.Fatalf("elements = %d, want 2", len(elems))
	}
	if elems[0] != nil {
		t.Errorf("elements[0] = %#v, want nil for a scalar", elems[0])
	}
	if got := elems[1].Keys(); !slices.Equal(got, []string{"x"}) {
		t.Errorf("elements[1] keys = %v, want [x]", got)
	}
}

func TestDocumentWithoutStatements(t *testing.T) {
	doc, err := Parse([]byte("# only a comment\n"))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if got := doc.Root().Keys(); len(got) != 0 {
		t.Errorf("keys = %v, want none", got)
	}
	if got := doc.Footer(); !slices.Equal(got, []string{"only a comment"}) {
		t.Errorf("footer = %q, want [only a comment]", got)
	}

	empty, err := Parse(nil)
	if err != nil {
		t.Fatalf("parse of nothing: %v", err)
	}
	if len(empty.Root().Keys()) != 0 || len(empty.Footer()) != 0 {
		t.Errorf("empty document = %v / %q", empty.Root().Keys(), empty.Footer())
	}
}

func TestParseMapIsTheValueTree(t *testing.T) {
	// ParseMap is the path that does not build a document, and it gives the
	// tree the decoder reads.
	tree, err := ParseMap([]byte("a = 1\n\n[t]\nb = \"x\"\n"))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if tree["a"] != int64(1) {
		t.Errorf("a = %#v", tree["a"])
	}
	if tree["t"].(map[string]any)["b"] != "x" {
		t.Errorf("t = %#v", tree["t"])
	}
}

func TestMarshalRejectsDocument(t *testing.T) {
	// A Document is not a value to marshal: its order and comments would be
	// dropped, and a struct walk would silently write nothing at all.
	doc, err := Parse([]byte("a = 1\n"))
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if _, err := Marshal(doc); err == nil {
		t.Fatal("expected an error for a Document")
	} else if !strings.Contains(err.Error(), "Map()") {
		t.Errorf("err = %v, want it to point at Map()", err)
	}
	if _, err := Marshal(*doc); err == nil {
		t.Fatal("expected an error for a Document value")
	}
	// The tree marshals, which is the way through.
	out, err := Marshal(doc.Map())
	if err != nil {
		t.Fatalf("marshal of the tree: %v", err)
	}
	if want := "a = 1\n"; string(out) != want {
		t.Errorf("output = %q, want %q", out, want)
	}
}