path: root/gui/internal/model/plan.go

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

// Package model is krino-gui's state and operations: what each tab shows,
// and what a click does. It holds no GTK, so it can be tested the way the
// engine's own packages are (GUI design §1.2).
package model

import (
	"context"
	"fmt"
	"sort"

	"krino/internal/engine"
	"krino/internal/lock"
	"krino/internal/plan"
)

// Row is one line of the Plan tab: a file krino would act on, or one it
// could not decide about.
type Row struct {
	Rel      string // the file, relative to the directory's root
	Steps    []plan.Step
	Rule     string // the rule that matched first, for the Rule column
	Warnings []string
	// Selected is the checkbox. A row that cannot be applied - every step
	// skipped, or nothing but warnings - is never selected and has no box.
	Selected bool
	Actable  bool
	// Outcome is what applying did to this file: "", "done", "failed: ...",
	// "declined".
	Outcome string
}

// PlanTab is the state of one directory's plan.
type PlanTab struct {
	Dir      *engine.Dir
	Rows     []Row
	Counts   Counts
	Warnings []string // directory-level
	Applied  bool     // this plan has been applied and is now history

	sess *engine.Session
	dp   *engine.DirPlan
	lock *lock.Lock
}

// Counts is the plan's summary line.
type Counts struct {
	Scanned, Acting, Excluded, Skipped, Unmatched, Warned int
}

// Plan locks d and plans it, returning the tab to show. The lock is held
// until Close, so what the window shows stays the truth while the user
// chooses, and no other krino moves the files under them (GUI design §3).
// A directory another run is already working in is not planned at all: the
// error is lock.ErrHeld, naming the directory.
func Plan(ctx context.Context, sess *engine.Session, d *engine.Dir) (*PlanTab, error) {
	l, err := sess.Lock(ctx, d, false)
	if err != nil {
		return nil, fmt.Errorf("%s: %w", d.Name, err)
	}
	// Start from what this run has actually landed: a name a plan the user
	// closed had reserved is free again, so looking twice never creeps up
	// through name-1, name-2 (spec §7.4).
	sess.FinishDirectory()
	dp, err := sess.Plan(ctx, d)
	if err != nil {
		l.Release()
		return nil, err
	}
	t := &PlanTab{Dir: d, sess: sess, dp: dp, lock: l}
	t.fill()
	return t, nil
}

// Close releases the directory's lock, which Apply also does once the plan
// is history. The session outlives the tab, so closing one plan to open
// another keeps the run - and its claims - going. Closing twice is not an
// error.
func (t *PlanTab) Close() error {
	if t.lock == nil {
		return nil
	}
	l := t.lock
	t.lock = nil
	return l.Release()
}

// fill turns the engine's plan into rows and counts.
func (t *PlanTab) fill() {
	r := t.dp.Result
	t.Warnings = append([]string(nil), r.Warnings...)
	warnings := map[string][]string{}
	for _, fms := range [][]engine.FileMatch{r.Matched, r.Unmatched} {
		for _, fm := range fms {
			if len(fm.Warnings) > 0 {
				warnings[fm.File.Rel] = fm.Warnings
			}
		}
	}
	excluded := 0
	for _, fm := range r.Matched {
		if fm.Excluded != "" {
			excluded++
		}
	}
	t.Rows = nil
	for _, c := range t.dp.Chains {
		row := Row{Rel: c.File.Rel, Steps: c.Steps, Warnings: warnings[c.File.Rel]}
		for _, s := range c.Steps {
			if s.Skip == "" {
				row.Actable = true
			}
			if row.Rule == "" {
				row.Rule = s.Rule
			}
		}
		row.Selected = row.Actable
		if len(c.Steps) > 0 {
			t.Rows = append(t.Rows, row)
		}
		delete(warnings, c.File.Rel)
	}
	// Files no rule acted on that still raised a warning: krino could not
	// decide about them, and they are shown but never selectable.
	var rest []string
	for rel := range warnings {
		rest = append(rest, rel)
	}
	sort.Strings(rest)
	for _, rel := range rest {
		t.Rows = append(t.Rows, Row{Rel: rel, Warnings: warnings[rel]})
	}
	t.Counts = Counts{
		Scanned:   len(r.Matched) + len(r.Unmatched) + len(r.Skipped),
		Excluded:  excluded,
		Skipped:   len(r.Skipped),
		Unmatched: len(r.Unmatched),
	}
	for _, row := range t.Rows {
		if row.Actable {
			t.Counts.Acting++
		}
		if len(row.Warnings) > 0 {
			t.Counts.Warned++
		}
	}
}

// SelectAll selects every row that can be applied; SelectNone clears them.
func (t *PlanTab) SelectAll()  { t.setAll(true) }
func (t *PlanTab) SelectNone() { t.setAll(false) }

func (t *PlanTab) setAll(on bool) {
	for i := range t.Rows {
		t.Rows[i].Selected = on && t.Rows[i].Actable
	}
}

// Toggle flips row i's checkbox; a row that cannot be applied stays off.
func (t *PlanTab) Toggle(i int) {
	if i < 0 || i >= len(t.Rows) || !t.Rows[i].Actable {
		return
	}
	t.Rows[i].Selected = !t.Rows[i].Selected
}

// SelectedCount is how many files Apply would act on.
func (t *PlanTab) SelectedCount() int {
	n := 0
	for _, r := range t.Rows {
		if r.Selected {
			n++
		}
	}
	return n
}

// Replace swaps a row's planned steps for the one step the user chose
// instead - "Trash instead", "Delete permanently instead" - as the terminal
// review's t and d keys do, and selects it.
func (t *PlanTab) Replace(i int, kind plan.Kind) error {
	if i < 0 || i >= len(t.Rows) {
		return fmt.Errorf("model: no row %d", i)
	}
	if kind != plan.Trash && kind != plan.DeletePermanent {
		return fmt.Errorf("model: %s is not a replacement action", kind)
	}
	rel := t.Rows[i].Rel
	for j, c := range t.dp.Chains {
		if c.File.Rel != rel {
			continue
		}
		t.dp.Chains[j].Steps = []plan.Step{{
			Kind:   kind,
			Rule:   "(review)",
			Src:    c.File.Path,
			Reason: "chosen in review",
		}}
		t.Rows[i].Steps = t.dp.Chains[j].Steps
		t.Rows[i].Rule = "(review)"
		t.Rows[i].Actable = true
		t.Rows[i].Selected = true
		return nil
	}
	return fmt.Errorf("model: %s is not in this plan", rel)
}

// Apply acts on the selected files and logs the rest as declined, exactly
// as choosing per file in the terminal does. Each row then carries its
// outcome.
func (t *PlanTab) Apply(ctx context.Context) (*engine.ApplyResult, error) {
	approved := map[string]bool{}
	for _, r := range t.Rows {
		if r.Selected {
			approved[r.Rel] = true
		}
	}
	res, err := t.sess.Apply(ctx, t.dp, approved)
	t.Applied = true
	// The disk is now the truth: a destination this plan reserved but never
	// used is free again, while one it did use stays protected for the rest
	// of the run (spec §7.4).
	t.sess.FinishDirectory()
	// An applied plan is history, so the directory is free again without
	// closing the window (GUI design §3).
	t.Close()
	if res != nil {
		t.record(res)
	}
	return res, err
}

// record writes each file's outcome onto its row.
func (t *PlanTab) record(res *engine.ApplyResult) {
	byRel := map[string]string{}
	for _, fr := range res.Files {
		outcome := "done"
		for _, sr := range fr.Steps {
			switch sr.Status {
			case "failed":
				outcome = "failed: " + sr.Detail
			case "declined":
				outcome = "declined"
			}
		}
		byRel[fr.File.Rel] = outcome
	}
	for i, r := range t.Rows {
		if o, ok := byRel[r.Rel]; ok {
			t.Rows[i].Outcome = o
		}
	}
}