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

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"strings"
	"testing"
	"unicode/utf8"

	"krino/internal/engine"
	"krino/internal/plan"
	"krino/internal/scan"
)

func chains(rels ...string) []plan.Chain {
	out := make([]plan.Chain, len(rels))
	for i, r := range rels {
		out[i] = plan.Chain{File: scan.File{Rel: r}, Steps: []plan.Step{{Kind: plan.Move, Dst: "/w/" + r}}}
	}
	return out
}

func TestChoosePerFile(t *testing.T) {
	// c enters per-file mode, then y n y for three files.
	approved, _, action, err := reviewChains(strings.NewReader("cyny"), new(strings.Builder), chains("a", "b", "c"), "", palette{})
	if err != nil {
		t.Fatal(err)
	}
	if action != 'c' {
		t.Errorf("action = %q", action)
	}
	if !approved["a"] || approved["b"] || !approved["c"] {
		t.Errorf("approved = %v; want a and c only", approved)
	}
}

func TestApplyAllAndSkip(t *testing.T) {
	approved, _, action, _ := reviewChains(strings.NewReader("a"), new(strings.Builder), chains("a", "b"), "", palette{})
	if action != 'a' || len(approved) != 2 {
		t.Errorf("[a] = %q %v; want every file approved", action, approved)
	}
	approved, _, action, _ = reviewChains(strings.NewReader("s"), new(strings.Builder), chains("a", "b"), "", palette{})
	if action != 's' || len(approved) != 0 {
		t.Errorf("[s] = %q %v; want nothing approved", action, approved)
	}
}

func TestPerFileWriteStopsAsking(t *testing.T) {
	// c, y for the first, n for the second, then w: apply what was chosen so
	// far and quit. Only the files reached are decided; c was never reviewed.
	decided, _, action, _ := reviewChains(strings.NewReader("cynw"), new(strings.Builder), chains("a", "b", "c"), "", palette{})
	if action != 'w' {
		t.Errorf("action = %q, want 'w'", action)
	}
	if got, ok := decided["b"]; !ok || got {
		t.Errorf("b should be decided as declined: %v", decided)
	}
	if _, ok := decided["c"]; ok || !decided["a"] {
		t.Errorf("decided = %v; want a approved, b declined, c not reviewed", decided)
	}
}

// TestPerFileQuitAppliesNothing: spec §8.3's [q] on the per-file prompt is
// "quit, apply nothing" - stronger than [w], which keeps what was already
// chosen. It folds into the same top-level 'q' the caller already handles
// for the directory-level menu (spec §8.2's [q]), and discards even a file
// already marked yes.
func TestPerFileQuitAppliesNothing(t *testing.T) {
	approved, _, action, err := reviewChains(strings.NewReader("cyq"), new(strings.Builder), chains("a", "b"), "", palette{})
	if err != nil {
		t.Fatal(err)
	}
	if action != 'q' {
		t.Errorf("action = %q, want 'q'", action)
	}
	if len(approved) != 0 {
		t.Errorf("approved = %v; want nothing, even though a was marked yes first", approved)
	}
}

// TestPerFileYesToAllRemaining: spec §8.3's [a] mid-review approves the
// current file and every remaining one without asking again.
func TestPerFileYesToAllRemaining(t *testing.T) {
	approved, _, action, err := reviewChains(strings.NewReader("ca"), new(strings.Builder), chains("a", "b", "c"), "", palette{})
	if err != nil {
		t.Fatal(err)
	}
	if action != 'c' || len(approved) != 3 {
		t.Errorf("approved = %v action = %q; want all three approved", approved, action)
	}
}

// TestInvalidKeyReprompts: an unrecognised key at either the top-level menu
// or the per-file prompt does not abort the review - it is reported and the
// same prompt is read again.
func TestInvalidKeyReprompts(t *testing.T) {
	out := new(strings.Builder)
	approved, _, action, err := reviewChains(strings.NewReader("zs"), out, chains("a"), "", palette{})
	if err != nil {
		t.Fatal(err)
	}
	if action != 's' || len(approved) != 0 {
		t.Errorf("approved = %v action = %q; want [s] after the bad key", approved, action)
	}
	if !strings.Contains(out.String(), "z") {
		t.Errorf("no mention of the rejected key:\n%s", out)
	}
}

// TestPerFileDestinationIsRootRelative is review finding 1 (fix round
// 2026-09-12): reviewPerFile must render a destination the same way the
// directory-level table does (render.go's destText) - root-relative for a
// destination inside root, ~-abbreviated for one outside it - not always
// abbreviated because root was never passed through to actionCell at all.
// Both halves are pinned: getting only the "inside" half right would still
// let an outside-root destination silently regress to some other form.
func TestPerFileDestinationIsRootRelative(t *testing.T) {
	t.Setenv("HOME", "/home/x")
	root := "/home/x/dl"
	cs := []plan.Chain{
		{File: scan.File{Rel: "inside.txt"}, Steps: []plan.Step{{Kind: plan.Move, Dst: root + "/Work/Acme/inside.txt"}}},
		{File: scan.File{Rel: "outside.txt"}, Steps: []plan.Step{{Kind: plan.Move, Dst: "/home/x/backup/outside.txt"}}},
	}
	out := new(strings.Builder)
	if _, _, _, err := reviewChains(strings.NewReader("cyy"), out, cs, root, palette{}); err != nil {
		t.Fatal(err)
	}
	text := out.String()
	if !strings.Contains(text, "move    → Work/Acme/") {
		t.Errorf("destination inside root should be root-relative, not ~-abbreviated:\n%s", text)
	}
	if !strings.Contains(text, "move    → ~/backup/") {
		t.Errorf("destination outside root should be ~-abbreviated:\n%s", text)
	}
}

// TestPerFileShowsTheWholeBlock: choosing per file shows each step, its
// rule and its reason: the same block the plan shows, not the steps alone.
func TestPerFileShowsTheWholeBlock(t *testing.T) {
	cs := []plan.Chain{{File: scan.File{Rel: "a.pdf"}, Steps: []plan.Step{
		{Kind: plan.Move, Rule: "acme", Dst: "/w/a.pdf", Reason: `content "acme ltd"`},
	}}}
	out := new(strings.Builder)
	if _, _, _, err := reviewChains(strings.NewReader("cy"), out, cs, "", palette{}); err != nil {
		t.Fatal(err)
	}
	want := "\n[1/1] a.pdf\n       move    → /w/\n       rule    acme\n       because content \"acme ltd\"\n"
	if !strings.Contains(out.String(), want) {
		t.Errorf("per-file prompt:\n%s\nwant substring:\n%s", out, want)
	}
}

// TestPerFileWrapsToTheTerminal: on a narrow terminal the per-file block
// and its key prompt both fit, and the prompt's pieces read back as the
// whole prompt.
func TestPerFileWrapsToTheTerminal(t *testing.T) {
	old := widthPolicy
	t.Cleanup(func() { widthPolicy = old })
	widthPolicy = func(io.Writer) int { return 60 }
	cs := []plan.Chain{{File: scan.File{Rel: "a.pdf"}, Steps: []plan.Step{
		{Kind: plan.Move, Rule: "acme", Dst: "/w/some/deeply/nested/destination/directory/for/invoices/a.pdf", Reason: `content "acme ltd"`},
	}}}
	out := new(strings.Builder)
	if _, _, _, err := reviewChains(strings.NewReader("cy"), out, cs, "", palette{}); err != nil {
		t.Fatal(err)
	}
	var prompt string
	for _, l := range strings.Split(out.String(), "\n") {
		if n := utf8.RuneCountInString(l); n > 60 {
			t.Errorf("line of %d runes exceeds width 60: %q", n, l)
		}
		if strings.HasPrefix(l, "  [y] yes") || (prompt != "" && strings.HasPrefix(l, "  ") && !strings.HasPrefix(l, "   ") && !strings.HasPrefix(l, "  →")) {
			prompt += strings.TrimPrefix(l, "  ")
		}
	}
	if prompt != perFileKeys {
		t.Errorf("wrapped prompt reads %q, want %q\n%s", prompt, perFileKeys, out)
	}
}

// TestPerFileTrashAndDelete: [t] and [d] (confirmed with y) replace what the
// rules planned for that file with one step, and approve it.
func TestPerFileTrashAndDelete(t *testing.T) {
	out := new(strings.Builder)
	approved, replaced, action, err := reviewChains(strings.NewReader("ctdyn"), out, chains("a", "b", "c"), "", palette{})
	if err != nil {
		t.Fatal(err)
	}
	if action != 'c' || !approved["a"] || !approved["b"] || approved["c"] {
		t.Errorf("approved = %v action = %q; want a and b", approved, action)
	}
	if len(replaced) != 2 || replaced["a"] != plan.Trash || replaced["b"] != plan.DeletePermanent {
		t.Errorf("replaced = %v; want a trash, b deleted permanently", replaced)
	}
	if !strings.Contains(out.String(), "delete b permanently? [y/N]") {
		t.Errorf("no confirmation asked:\n%s", out)
	}
}

// TestPerFileDeleteNeedsConfirmation: any key but y after [d] deletes
// nothing and asks about the same file again.
func TestPerFileDeleteNeedsConfirmation(t *testing.T) {
	out := new(strings.Builder)
	approved, replaced, _, err := reviewChains(strings.NewReader("cdny"), out, chains("a"), "", palette{})
	if err != nil {
		t.Fatal(err)
	}
	if len(replaced) != 0 || !approved["a"] {
		t.Errorf("approved = %v replaced = %v; want a approved as planned, nothing replaced", approved, replaced)
	}
	if strings.Count(out.String(), perFileKeys) != 2 {
		t.Errorf("the prompt should be shown again after a cancelled delete:\n%s", out)
	}
}

// TestPerFileQuitDiscardsReplacements: [q] after [t] applies nothing, the
// trash included.
func TestPerFileQuitDiscardsReplacements(t *testing.T) {
	approved, replaced, action, _ := reviewChains(strings.NewReader("ctq"), new(strings.Builder), chains("a", "b"), "", palette{})
	if action != 'q' || len(approved) != 0 || len(replaced) != 0 {
		t.Errorf("approved = %v replaced = %v action = %q; want nothing", approved, replaced, action)
	}
}

// TestReplaceChains: a replaced file's chain becomes one step of the chosen
// kind on the file itself, under the rule name (review); other chains keep
// their steps.
func TestReplaceChains(t *testing.T) {
	cs := chains("a", "b")
	cs[0].File.Path = "/dl/a"
	cs[0].Steps = append(cs[0].Steps, plan.Step{Kind: plan.Copy, Dst: "/w/copy"})
	got := replaceChains(cs, map[string]plan.Kind{"a": plan.DeletePermanent})
	want := plan.Step{Kind: plan.DeletePermanent, Rule: "(review)", Src: "/dl/a", Reason: "chosen in review"}
	if len(got[0].Steps) != 1 || got[0].Steps[0] != want {
		t.Errorf("a's steps = %+v; want only %+v", got[0].Steps, want)
	}
	if len(got[1].Steps) != 1 || got[1].Steps[0].Kind != plan.Move {
		t.Errorf("b's steps changed: %+v", got[1].Steps)
	}
	if len(cs[0].Steps) != 2 {
		t.Errorf("replaceChains changed its input: %+v", cs[0].Steps)
	}
}

// TestPerFileEchoesChoiceInRed: every choice is confirmed on its own line,
// red when colour is on.
func TestPerFileEchoesChoiceInRed(t *testing.T) {
	out := new(strings.Builder)
	if _, _, _, err := reviewChains(strings.NewReader("cyntdya"), out, chains("a", "b", "c", "d", "e", "f"), "", palette{on: true}); err != nil {
		t.Fatal(err)
	}
	for _, want := range []string{"yes", "no", "trash", "DELETE permanently", "yes, and all remaining"} {
		if line := "  \x1b[31m→ " + want + "\x1b[0m\n"; !strings.Contains(out.String(), line) {
			t.Errorf("no red %q line in:\n%q", want, out)
		}
	}
	plain := new(strings.Builder)
	reviewChains(strings.NewReader("cn"), plain, chains("a"), "", palette{})
	if !strings.Contains(plain.String(), "\n  → no\n") {
		t.Errorf("without colour the choice should still be shown:\n%s", plain)
	}
}

// TestEnterIsIgnored: Enter, at either prompt, is not a key krino
// complains about.
func TestEnterIsIgnored(t *testing.T) {
	out := new(strings.Builder)
	decided, _, action, err := reviewChains(strings.NewReader("\rc\ry\n"), out, chains("a"), "", palette{})
	if err != nil {
		t.Fatal(err)
	}
	if action != 'c' || !decided["a"] {
		t.Errorf("decided = %v action = %q", decided, action)
	}
	if strings.Contains(out.String(), "is not") {
		t.Errorf("Enter was reported as a bad key:\n%s", out)
	}
}

// TestReviewedChains: after [w], only the files decided in review go to
// Apply; the rest are neither applied nor logged.
func TestReviewedChains(t *testing.T) {
	got := reviewedChains(chains("a", "b", "c"), map[string]bool{"a": true, "b": false})
	if len(got) != 2 || got[0].File.Rel != "a" || got[1].File.Rel != "b" {
		t.Errorf("reviewedChains = %+v; want a and b", got)
	}
}

// TestNotReviewedOutcome: the outcome line counts files [w] left unreviewed.
func TestNotReviewedOutcome(t *testing.T) {
	if got := withNotReviewed("2 applied · 0 failed · 1 declined", 139); got != "2 applied · 0 failed · 1 declined · 139 not reviewed" {
		t.Errorf("got %q", got)
	}
	if got := withNotReviewed("2 applied · 0 failed · 1 declined", 0); got != "2 applied · 0 failed · 1 declined" {
		t.Errorf("got %q", got)
	}
}

// TestStopAfterApply: [w] stops krino after its directory whether or not the
// apply succeeded (review cli F3) - a log that cannot be written must not
// lead on to planning and prompting the next directory - and an interrupt
// always stops it.
func TestStopAfterApply(t *testing.T) {
	logErr := errors.New("write krino.log: no space left on device")
	cases := []struct {
		action rune
		err    error
		want   bool
	}{
		{'a', nil, false},
		{'c', nil, false},
		{'w', nil, true},
		{'a', logErr, false},
		{'c', logErr, false},
		{'w', logErr, true},
		{'a', context.Canceled, true},
		{'c', fmt.Errorf("apply: %w", context.Canceled), true},
		{'a', context.DeadlineExceeded, true},
	}
	for _, c := range cases {
		if got := stopAfterApply(c.action, c.err); got != c.want {
			t.Errorf("stopAfterApply(%q, %v) = %v, want %v", c.action, c.err, got, c.want)
		}
	}
}

// TestReviewHeadingsCannotFakeAStepLine: a long name in the per-file
// heading of review and of undo wraps with its continuation past the column
// step labels use, so the name cannot pass for a step (plan 11 review L4).
func TestReviewHeadingsCannotFakeAStepLine(t *testing.T) {
	old := widthPolicy
	t.Cleanup(func() { widthPolicy = old })
	widthPolicy = func(io.Writer) int { return 60 }
	name := strings.Repeat("x", 50) + "       DELETE permanently"

	out := new(strings.Builder)
	cs := []plan.Chain{{File: scan.File{Rel: name}, Steps: []plan.Step{{Kind: plan.Move, Rule: "r", Dst: "/w/Out/a.pdf"}}}}
	if _, _, _, err := reviewChains(strings.NewReader("cy"), out, cs, "/w", palette{}); err != nil {
		t.Fatal(err)
	}
	for _, l := range strings.Split(out.String(), "\n") {
		if strings.HasPrefix(strings.TrimLeft(l, " "), "DELETE") {
			t.Errorf("review: a line reads as a step: %q\n%s", l, out)
		}
		if n := cols(l); n > 60 {
			t.Errorf("review: a line of %d columns, over 60, which the terminal wraps: %q", n, l)
		}
	}

	out.Reset()
	files := []engine.UndoFile{{Dir: "dl", File: name, Steps: []engine.UndoStep{{Action: "undo-move", Src: "/t/a", Dst: "/s/a"}}}}
	if _, _, err := reviewUndoFiles(strings.NewReader("cy"), out, files, palette{}); err != nil {
		t.Fatal(err)
	}
	for _, l := range strings.Split(out.String(), "\n") {
		if strings.HasPrefix(strings.TrimLeft(l, " "), "DELETE") {
			t.Errorf("undo: a line reads as a step: %q\n%s", l, out)
		}
		if n := cols(l); n > 60 {
			t.Errorf("undo: a line of %d columns, over 60, which the terminal wraps: %q", n, l)
		}
	}
}