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

package extract

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

// fakeTool writes an executable shell script named name into dir.
func fakeTool(t *testing.T, dir, name, body string) {
	t.Helper()
	script := "#!/bin/sh\n" + body + "\n"
	if err := os.WriteFile(filepath.Join(dir, name), []byte(script), 0o755); err != nil {
		t.Fatal(err)
	}
}

func TestPdfViaFakeTool(t *testing.T) {
	bin := t.TempDir()
	argsFile := filepath.Join(t.TempDir(), "args")
	fakeTool(t, bin, "pdftotext", `printf '%s\n' "$@" > "`+argsFile+`"; echo "acme ltd invoice"`)
	e := newWithPath(bin)
	p := file(t, "-leading-dash.pdf", []byte("%PDF-1.4"))
	got, err := text(t, e, p, 0)
	if err != nil || strings.TrimSpace(got) != "acme ltd invoice" {
		t.Fatalf("got %q, %v", got, err)
	}
	args, _ := os.ReadFile(argsFile)
	want := "-q\n-enc\nUTF-8\n" + p + "\n-\n"
	if string(args) != want {
		t.Fatalf("pdftotext args:\n%q\nwant\n%q", args, want)
	}
	if !filepath.IsAbs(strings.Split(string(args), "\n")[3]) {
		t.Fatal("path argument is not absolute")
	}
}

func TestLegacyFormats(t *testing.T) {
	bin := t.TempDir()
	fakeTool(t, bin, "catdoc", `echo "from catdoc"`)
	fakeTool(t, bin, "xls2csv", `echo "from xls2csv"`)
	fakeTool(t, bin, "catppt", `echo "from catppt"`)
	e := newWithPath(bin) // no antiword: .doc falls back to catdoc
	for ext, want := range map[string]string{"doc": "from catdoc", "xls": "from xls2csv", "ppt": "from catppt"} {
		got, err := text(t, e, file(t, "f."+ext, []byte("x")), 0)
		if err != nil || strings.TrimSpace(got) != want {
			t.Errorf("%s: got %q, %v", ext, got, err)
		}
	}
	fakeTool(t, bin, "antiword", `echo "from antiword"`)
	e = newWithPath(bin)
	if got, _ := text(t, e, file(t, "g.doc", []byte("x")), 0); strings.TrimSpace(got) != "from antiword" {
		t.Errorf("antiword not preferred: %q", got)
	}
	fakeTool(t, bin, "antiword", `echo "antiword broke" >&2; exit 1`)
	e = newWithPath(bin)
	if got, _ := text(t, e, file(t, "h.doc", []byte("x")), 0); strings.TrimSpace(got) != "from catdoc" {
		t.Errorf("no fallback to catdoc after antiword failed: %q", got)
	}
}

func TestToolErrors(t *testing.T) {
	e := newWithPath(t.TempDir())
	var tm *ToolMissingError
	if _, err := text(t, e, file(t, "a.pdf", []byte("x")), 0); !errors.As(err, &tm) || tm.Error() != "needs pdftotext, not installed" {
		t.Errorf("missing pdftotext: %v", err)
	}
	if _, err := text(t, e, file(t, "a.doc", []byte("x")), 0); err == nil || err.Error() != "needs antiword or catdoc, not installed" {
		t.Errorf("missing doc tools: %v", err)
	}
	bin := t.TempDir()
	fakeTool(t, bin, "pdftotext", `echo "Syntax Error: broken xref" >&2; exit 3`)
	e = newWithPath(bin)
	if _, err := text(t, e, file(t, "b.pdf", []byte("x")), 0); err == nil || err.Error() != "pdftotext failed: Syntax Error: broken xref" {
		t.Errorf("failing tool: %v", err)
	}
	fakeTool(t, bin, "pdftotext", `sleep 5`)
	e = newWithPath(bin)
	e.Timeout = 200 * time.Millisecond
	start := time.Now()
	_, err := text(t, e, file(t, "c.pdf", []byte("x")), 0)
	if err == nil || !strings.Contains(err.Error(), "pdftotext timed out after 200ms") {
		t.Errorf("slow tool: %v", err)
	}
	if time.Since(start) > 3*time.Second {
		t.Errorf("timeout took %v", time.Since(start))
	}
}

// minimalPDF returns a valid one-page PDF showing text in Helvetica.
func minimalPDF(text string) []byte {
	var b bytes.Buffer
	var offsets []int
	obj := func(s string) { offsets = append(offsets, b.Len()); b.WriteString(s) }
	b.WriteString("%PDF-1.4\n")
	obj("1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj\n")
	obj("2 0 obj << /Type /Pages /Kids [3 0 R] /Count 1 >> endobj\n")
	obj("3 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Contents 4 0 R /Resources << /Font << /F1 5 0 R >> >> >> endobj\n")
	stream := "BT /F1 24 Tf 72 700 Td (" + text + ") Tj ET"
	obj(fmt.Sprintf("4 0 obj << /Length %d >> stream\n%s\nendstream endobj\n", len(stream), stream))
	obj("5 0 obj << /Type /Font /Subtype /Type1 /BaseFont /Helvetica >> endobj\n")
	xref := b.Len()
	fmt.Fprintf(&b, "xref\n0 %d\n0000000000 65535 f \n", len(offsets)+1)
	for _, o := range offsets {
		fmt.Fprintf(&b, "%010d 00000 n \n", o)
	}
	fmt.Fprintf(&b, "trailer << /Size %d /Root 1 0 R >>\nstartxref\n%d\n%%%%EOF\n", len(offsets)+1, xref)
	return b.Bytes()
}

func TestRealPdftotext(t *testing.T) {
	if _, err := exec.LookPath("pdftotext"); err != nil {
		t.Skip("pdftotext not installed")
	}
	e := New()
	got, err := text(t, e, file(t, "hello.pdf", minimalPDF("Hello acme ltd")), 0)
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(got, "Hello acme ltd") {
		t.Fatalf("pdftotext gave %q", got)
	}
}

// TestOrphanChildDoesNotHangRun: a tool that exits itself but leaves a
// backgrounded grandchild holding its stdout pipe open must not make
// run() wait for that grandchild. Only os/exec itself, copying into
// cmd.Stdout and bounding the post-exit wait via WaitDelay, can end this
// promptly; run() manually draining a StdoutPipe before calling Wait
// starves WaitDelay of the thing it bounds, since by the time Wait runs
// there is nothing left for it to forcibly cut off.
func TestOrphanChildDoesNotHangRun(t *testing.T) {
	bin := t.TempDir()
	fakeTool(t, bin, "pdftotext", "sleep 5 & echo x")
	e := newWithPath(bin)
	e.Timeout = 30 * time.Second

	start := time.Now()
	got, err := e.run(context.Background(), maxToolOutput, "pdftotext")
	if err != nil {
		t.Fatalf("orphan: %v", err)
	}
	if strings.TrimSpace(got) != "x" {
		t.Errorf("orphan: got %q, want %q", got, "x")
	}
	if d := time.Since(start); d > 3*time.Second {
		t.Errorf("orphan: took %v, want well under e.Timeout (30s) and under 3s", d)
	}
}

// TestStdoutOverflowKillsToolPromptly: a tool that keeps writing past
// maxToolOutput must be killed the moment the cap is crossed, not left
// running until e.Timeout expires — once run() stops draining its pipe,
// an unkilled tool blocks on its own write() and never exits on its own.
func TestStdoutOverflowKillsToolPromptly(t *testing.T) {
	old := maxToolOutput
	maxToolOutput = 1 << 20
	defer func() { maxToolOutput = old }()

	bin := t.TempDir()
	fakeTool(t, bin, "pdftotext", "yes aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
	e := newWithPath(bin)
	e.Timeout = 30 * time.Second

	start := time.Now()
	_, err := e.run(context.Background(), maxToolOutput, "pdftotext")
	if !errors.Is(err, ErrTooLarge) {
		t.Fatalf("overflow: got %v, want ErrTooLarge", err)
	}
	if d := time.Since(start); d > 5*time.Second {
		t.Errorf("overflow: took %v, want under 5s (well under e.Timeout=30s)", d)
	}
}

// TestCallerCancelReturnsPromptly: cancelling the ctx passed to run()
// (distinct from e.Timeout's own internal deadline, which is untouched
// here) must stop the tool and return quickly, with an error wrapping
// the caller's own context.Canceled — not silently absorbed into a
// generic "<tool> failed: ..." string, and not held open until
// e.Timeout.
func TestCallerCancelReturnsPromptly(t *testing.T) {
	bin := t.TempDir()
	fakeTool(t, bin, "pdftotext", "sleep 10")
	e := newWithPath(bin)
	e.Timeout = 30 * time.Second

	ctx, cancel := context.WithCancel(context.Background())
	time.AfterFunc(100*time.Millisecond, cancel)

	start := time.Now()
	_, err := e.run(ctx, maxToolOutput, "pdftotext")
	if !errors.Is(err, context.Canceled) {
		t.Fatalf("caller cancel: got %v, want an error wrapping context.Canceled", err)
	}
	if d := time.Since(start); d > 3*time.Second {
		t.Errorf("caller cancel: took %v, want under 3s", d)
	}
}

// TestStderrFloodBounded: a tool that floods stderr must not blow up the
// size of the error message run() produces — only a bounded prefix of
// its first line may ever reach the returned error text, and capturing
// it at all must not cost unbounded memory.
func TestStderrFloodBounded(t *testing.T) {
	bin := t.TempDir()
	fakeTool(t, bin, "pdftotext", `head -c 10000000 /dev/zero | tr '\0' x >&2; exit 1`)
	e := newWithPath(bin)

	_, err := e.run(context.Background(), maxToolOutput, "pdftotext")
	if err == nil {
		t.Fatal("stderr flood: want an error")
	}
	if max := len("pdftotext failed: ") + 200; len(err.Error()) > max {
		t.Errorf("stderr flood: message is %d bytes, want <=%d", len(err.Error()), max)
	}
}

// TestMaxReadCapsToolOutput: B1. A directory's max-read, when smaller than
// the fixed maxToolOutput default, caps a single tool's output on its
// own — proven here with maxToolOutput left at its default, so only
// budget(maxToolOutput, maxRead) picking the smaller maxRead explains the
// result.
func TestMaxReadCapsToolOutput(t *testing.T) {
	bin := t.TempDir()
	fakeTool(t, bin, "pdftotext", `yes aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | head -c 200000`)
	e := newWithPath(bin)
	if _, err := text(t, e, file(t, "small.pdf", []byte("%PDF-1.4")), 1024); !errors.Is(err, ErrTooLarge) {
		t.Fatalf("got %v, want ErrTooLarge (max-read 1024 should have capped a 200000-byte tool output)", err)
	}
}

// TestFingerprintFollowsTools: the fingerprint changes when a tool is
// installed or replaced, and not otherwise.
func TestFingerprintFollowsTools(t *testing.T) {
	bin := t.TempDir()
	none := newWithPath(bin).Fingerprint()
	if none != newWithPath(bin).Fingerprint() {
		t.Fatal("fingerprint not stable")
	}
	tool := filepath.Join(bin, "pdftotext")
	if err := os.WriteFile(tool, []byte("#!/bin/sh\n"), 0o755); err != nil {
		t.Fatal(err)
	}
	installed := newWithPath(bin).Fingerprint()
	if installed == none {
		t.Error("installing pdftotext did not change the fingerprint")
	}
	if err := os.WriteFile(tool, []byte("#!/bin/sh\nexit 0\n"), 0o755); err != nil {
		t.Fatal(err)
	}
	if newWithPath(bin).Fingerprint() == installed {
		t.Error("replacing pdftotext did not change the fingerprint")
	}
}

// TestToolLookupSkipsRelativePathEntries: a relative PATH entry would make
// a tool's path relative to the working directory - a bin/pdftotext left by
// an unpacked download - so it is ignored (review planapply F7).
func TestToolLookupSkipsRelativePathEntries(t *testing.T) {
	wd := t.TempDir()
	if err := os.Mkdir(filepath.Join(wd, "bin"), 0o755); err != nil {
		t.Fatal(err)
	}
	fakeTool(t, filepath.Join(wd, "bin"), "pdftotext", "echo injected")
	t.Chdir(wd)
	if e := newWithPath("bin"); e.tools["pdftotext"] != "" {
		t.Errorf("tool found through a relative PATH entry: %q", e.tools["pdftotext"])
	}
}