// SPDX-License-Identifier: GPL-3.0-or-later

package cond

import (
	"errors"
	"math/rand"
	"reflect"
	"strings"
	"testing"
	"time"

	"krino/internal/norm"
)

var now = time.Date(2026, 9, 11, 12, 0, 0, 0, time.UTC)

type fake struct {
	name, rel, raw string
	rawErr         error
	size           int64
	age            time.Duration
	matched        bool
	dupOrig        string
	dupOK          bool
	contentCalls   int
}

func (f *fake) Name() string { return f.name }
func (f *fake) Rel() string {
	if f.rel != "" {
		return f.rel
	}
	return f.name
}
func (f *fake) Size() int64        { return f.size }
func (f *fake) ModTime() time.Time { return now.Add(-f.age) }
func (f *fake) Now() time.Time     { return now }
func (f *fake) Matched() bool      { return f.matched }
func (f *fake) ContentContains(opt Options, keywords []string) (int, error) {
	f.contentCalls++
	if f.rawErr != nil {
		return -1, f.rawErr
	}
	text := norm.Text(f.raw, opt.IgnoreCase, opt.Fold)
	for i, kw := range keywords {
		if strings.Contains(text, kw) {
			return i, nil
		}
	}
	return -1, nil
}
func (f *fake) Duplicate(dirs []string) (string, bool, error) { return f.dupOrig, f.dupOK, nil }

func eval(t *testing.T, src string, opt Options, f Facts) Result {
	t.Helper()
	c, errs := Compile("d.conf", nodes(t, src), opt)
	if len(errs) > 0 {
		t.Fatalf("%s: %v", src, errs)
	}
	return c.Eval(f)
}

func TestTruth(t *testing.T) {
	ic := Options{IgnoreCase: true}
	pdf := &fake{name: "Scan001.PDF", raw: "Invoice from ACME LTD", size: 20 << 20, age: 40 * 24 * time.Hour}
	tests := []struct {
		src  string
		want bool
	}{
		{``, true},
		{`(type pdf)`, true},
		{`(type document)`, true},
		{`(type jpg)`, false},
		{`(type pdf) (size > 10M)`, true},
		{`(type pdf) (size < 10M)`, false},
		{`(or (type jpg) (content "acme ltd"))`, true},
		{`(not (content "acme ltd"))`, false},
		{`(age > 30d) (age <= 41d)`, true},
		{`(name "^scan\d+")`, true},
		{`(name "(?-i)^scan")`, false},
		{`(matched)`, false},
		{`(and (type pdf) (or (name "^x") (not (name "^y"))))`, true},
	}
	for _, tt := range tests {
		if got := eval(t, tt.src, ic, pdf); got.Match != tt.want {
			t.Errorf("%s = %v, want %v (%+v)", tt.src, got.Match, tt.want, got)
		}
	}
}

func TestCaseAndFold(t *testing.T) {
	f := &fake{name: "SPOLKA-umowa.pdf", raw: "Umowa: spółka z o.o."}
	if !eval(t, `(name "spółka")`, Options{IgnoreCase: true, Fold: true}, f).Match {
		t.Error("folded, case-ignoring name did not match")
	}
	if eval(t, `(name "spółka")`, Options{IgnoreCase: true, Fold: false}, f).Match {
		t.Error("matched without folding")
	}
	if !eval(t, `(content "SPOLKA Z O.O.")`, Options{IgnoreCase: true, Fold: true}, f).Match {
		t.Error("folded content did not match")
	}
	img := &fake{name: "IMG_0001.jpg"}
	if eval(t, `(name "^img")`, Options{IgnoreCase: false}, img).Match {
		t.Error("strict case matched")
	}
	if !eval(t, `(name "(?i)^img")`, Options{IgnoreCase: false}, img).Match {
		t.Error("inline (?i) did not override strict case")
	}
}

func TestReasonsAndCaptures(t *testing.T) {
	f := &fake{name: "Screenshot_20260911.png", raw: "acme ltd"}
	r := eval(t, `(type image) (name "^Screenshot_(\d{4})(\d{2})") (not (name "^x(y)"))`, Options{IgnoreCase: true}, f)
	if !r.Match {
		t.Fatal("no match")
	}
	if want := []string{"Screenshot_202609", "2026", "09"}; !reflect.DeepEqual(r.Captures, want) {
		t.Errorf("captures = %q, want %q", r.Captures, want)
	}
	if want := []string{`type png`, `name "^Screenshot_(\d{4})(\d{2})"`, `not name "^x(y)"`}; !reflect.DeepEqual(r.Reasons, want) {
		t.Errorf("reasons = %q, want %q", r.Reasons, want)
	}
	r = eval(t, `(or (content "nope" "acme ltd") (type png))`, Options{IgnoreCase: true}, f)
	if want := []string{`type png`}; !reflect.DeepEqual(r.Reasons, want) {
		t.Errorf("or reasons = %q, want %q (cheapest true child)", r.Reasons, want)
	}
	r = eval(t, `(content "nope" "acme ltd")`, Options{IgnoreCase: true}, f)
	if want := []string{`content "acme ltd"`}; !reflect.DeepEqual(r.Reasons, want) {
		t.Errorf("content reasons = %q, want %q", r.Reasons, want)
	}
	if r := eval(t, ``, Options{}, f); !reflect.DeepEqual(r.Reasons, []string{"no condition"}) {
		t.Errorf("empty reasons = %q", r.Reasons)
	}
	d := &fake{name: "report (1).pdf", dupOrig: "report.pdf", dupOK: true}
	if r := eval(t, `(duplicate)`, Options{}, d); !r.Match || r.Reasons[0] != "duplicate of report.pdf" {
		t.Errorf("duplicate = %+v", r)
	}
}

func TestCheapFirstAvoidsContent(t *testing.T) {
	f := &fake{name: "a.txt", raw: "x"}
	eval(t, `(and (content "x") (type pdf))`, Options{}, f)
	if f.contentCalls != 0 {
		t.Errorf("content read although type was false (%d calls)", f.contentCalls)
	}
	g := &fake{name: "a.pdf", raw: "x"}
	eval(t, `(or (content "x") (type pdf))`, Options{}, g)
	if g.contentCalls != 0 {
		t.Errorf("content read although type was true (%d calls)", g.contentCalls)
	}
}

func TestContentErrorWarns(t *testing.T) {
	f := &fake{name: "a.pdf", rawErr: errors.New("needs pdftotext, not installed")}
	r := eval(t, `(or (content "acme") (content "other"))`, Options{}, f)
	if r.Match {
		t.Fatal("matched unreadable content")
	}
	if want := []string{"content unreadable: needs pdftotext, not installed"}; !reflect.DeepEqual(r.Warnings, want) {
		t.Errorf("warnings = %q, want %q (de-duplicated)", r.Warnings, want)
	}
}

func TestExplainFormat(t *testing.T) {
	f := &fake{name: "scan.pdf", rawErr: errors.New("needs pdftotext, not installed")}
	c, _ := Compile("d.conf", nodes(t, `(type pdf) (or (content "acme ltd") (name "\bacme\b"))`), Options{IgnoreCase: true})
	var b strings.Builder
	c.Explain(f).Format(&b)
	want := "no   and\n" +
		"yes    type pdf\n" +
		"no     or\n" +
		"no       name \"\\bacme\\b\"\n" +
		"no       content \"acme ltd\"  (content unreadable: needs pdftotext, not installed)\n"
	if b.String() != want {
		t.Fatalf("got\n%s\nwant\n%s", b.String(), want)
	}
}

// TestReorderKeepsMeaning: random trees give the same answer with and without
// cost reordering.
func TestReorderKeepsMeaning(t *testing.T) {
	leaves := []string{`(type pdf)`, `(type txt)`, `(name "^a")`, `(name "b$")`, `(size > 10)`, `(size < 5)`,
		`(age > 1d)`, `(content "x")`, `(content "y")`, `(matched)`}
	rng := rand.New(rand.NewSource(1))
	var gen func(depth int) string
	gen = func(depth int) string {
		if depth == 0 || rng.Intn(3) == 0 {
			return leaves[rng.Intn(len(leaves))]
		}
		switch rng.Intn(3) {
		case 0:
			return "(not " + gen(depth-1) + ")"
		case 1:
			return "(and " + gen(depth-1) + " " + gen(depth-1) + ")"
		default:
			return "(or " + gen(depth-1) + " " + gen(depth-1) + " " + gen(depth-1) + ")"
		}
	}
	names := []string{"a.pdf", "b.txt", "ab.pdf", "c.jpg"}
	for i := 0; i < 500; i++ {
		src := gen(4)
		f := &fake{name: names[rng.Intn(len(names))], raw: []string{"x", "y", "xy", ""}[rng.Intn(4)],
			size: int64(rng.Intn(20)), age: time.Duration(rng.Intn(72)) * time.Hour, matched: rng.Intn(2) == 0}
		a, _ := compile("d.conf", nodes(t, src), Options{}, true)
		b, _ := compile("d.conf", nodes(t, src), Options{}, false)
		if ra, rb := a.Eval(f), b.Eval(f); ra.Match != rb.Match {
			t.Fatalf("%s on %+v: reordered %v, original %v", src, f, ra.Match, rb.Match)
		}
	}
}

// TestNegatedCombinatorReason: E4. Negating a combinator must read as
// something a person would write ("not (and ...)" / "not (or ...)"), not
// the bare "not and" / "not or"; a negated leaf keeps its own label
// unchanged ("not matched").
func TestNegatedCombinatorReason(t *testing.T) {
	f := &fake{name: "a.pdf"}
	if r := eval(t, `(not (and (type pdf) (matched)))`, Options{}, f); !r.Match || r.Reasons[0] != "not (and ...)" {
		t.Errorf("negated and = %+v, want reason %q", r, "not (and ...)")
	}
	if r := eval(t, `(not (or (matched) (name "^zzz")))`, Options{}, f); !r.Match || r.Reasons[0] != "not (or ...)" {
		t.Errorf("negated or = %+v, want reason %q", r, "not (or ...)")
	}
	if r := eval(t, `(not (matched))`, Options{}, f); !r.Match || r.Reasons[0] != "not matched" {
		t.Errorf("negated leaf = %+v, want its own label unchanged: %q", r, "not matched")
	}
}

// TestEvalReportsUnreadableContent: Result.Unreadable says a content test
// was reached and could not read the file - what lets an exclude fail
// closed (review M11) - and stays false when evaluation never reached the
// content test.
func TestEvalReportsUnreadableContent(t *testing.T) {
	f := &fake{name: "a.pdf", rawErr: errors.New("larger than max-read")}
	if r := eval(t, `(and (type pdf) (content "x"))`, Options{}, f); r.Match || !r.Unreadable {
		t.Errorf("reached: Match %v Unreadable %v; want false, true", r.Match, r.Unreadable)
	}
	if r := eval(t, `(or (name "^a") (content "x"))`, Options{}, f); !r.Match || r.Unreadable {
		t.Errorf("not reached: Match %v Unreadable %v; want true, false", r.Match, r.Unreadable)
	}
}