package main

import (
	"fmt"
	"strings"
	"unicode/utf8"
)

type KeyBindings struct {
	General    GeneralKeyBindings    `toml:"general"`
	Navigation NavigationKeyBindings `toml:"navigation"`
	Views      ViewKeyBindings       `toml:"views"`
	Threads    ThreadKeyBindings     `toml:"threads"`
	Input      InputKeyBindings      `toml:"input"`
	Vim        VimKeyBindings        `toml:"vim"`
}

type GeneralKeyBindings struct {
	Quit    []string `toml:"quit"`
	Help    []string `toml:"help"`
	Refresh []string `toml:"refresh"`
	Back    []string `toml:"back"`
	Confirm []string `toml:"confirm"`
	Reject  []string `toml:"reject"`
}

type NavigationKeyBindings struct {
	Down     []string `toml:"down"`
	Up       []string `toml:"up"`
	Left     []string `toml:"left"`
	Right    []string `toml:"right"`
	First    []string `toml:"first"`
	Last     []string `toml:"last"`
	PageDown []string `toml:"page_down"`
	PageUp   []string `toml:"page_up"`
}

type ViewKeyBindings struct {
	Open       []string `toml:"open"`
	Dashboard  []string `toml:"dashboard"`
	Health     []string `toml:"health"`
	Edit       []string `toml:"edit"`
	AutoMerge  []string `toml:"auto_merge"`
	MergeNow   []string `toml:"merge_now"`
	ToggleList []string `toml:"toggle_list"`
	AI         []string `toml:"ai"`
}

type ThreadKeyBindings struct {
	Search         []string `toml:"search"`
	ClearFilter    []string `toml:"clear_filter"`
	NextUnread     []string `toml:"next_unread"`
	PreviousUnread []string `toml:"previous_unread"`
	MarkRead       []string `toml:"mark_read"`
	Reply          []string `toml:"reply"`
	Resolve        []string `toml:"resolve"`
	Toggle         []string `toml:"toggle"`
	FoldPrefix     []string `toml:"fold_prefix"`
	FoldToggle     []string `toml:"fold_toggle"`
}

type InputKeyBindings struct {
	Cancel             []string `toml:"cancel"`
	Submit             []string `toml:"submit"`
	Newline            []string `toml:"newline"`
	DeleteBackward     []string `toml:"delete_backward"`
	DeleteForward      []string `toml:"delete_forward"`
	Clear              []string `toml:"clear"`
	NextField          []string `toml:"next_field"`
	PreviousField      []string `toml:"previous_field"`
	NextCompletion     []string `toml:"next_completion"`
	PreviousCompletion []string `toml:"previous_completion"`
	LineStart          []string `toml:"line_start"`
	LineEnd            []string `toml:"line_end"`
}

type VimKeyBindings struct {
	Insert            []string `toml:"insert"`
	Append            []string `toml:"append"`
	InsertLineStart   []string `toml:"insert_line_start"`
	AppendLineEnd     []string `toml:"append_line_end"`
	OpenBelow         []string `toml:"open_below"`
	OpenAbove         []string `toml:"open_above"`
	ReplaceCharacter  []string `toml:"replace_character"`
	Visual            []string `toml:"visual"`
	VisualLine        []string `toml:"visual_line"`
	SelectionOtherEnd []string `toml:"selection_other_end"`
	Yank              []string `toml:"yank"`
	Delete            []string `toml:"delete"`
	DeleteBefore      []string `toml:"delete_before"`
	Paste             []string `toml:"paste"`
	LineStart         []string `toml:"line_start"`
	FirstNonBlank     []string `toml:"first_non_blank"`
	LineEnd           []string `toml:"line_end"`
	WordForward       []string `toml:"word_forward"`
	WORDForward       []string `toml:"big_word_forward"`
	WordBackward      []string `toml:"word_backward"`
	WORDBackward      []string `toml:"big_word_backward"`
	WordEnd           []string `toml:"word_end"`
	WORDEnd           []string `toml:"big_word_end"`
	GoPrefix          []string `toml:"go_prefix"`
	FindForward       []string `toml:"find_forward"`
	FindBackward      []string `toml:"find_backward"`
	TillForward       []string `toml:"till_forward"`
	TillBackward      []string `toml:"till_backward"`
	RepeatFind        []string `toml:"repeat_find"`
	RepeatFindReverse []string `toml:"repeat_find_reverse"`
}

func defaultKeyBindings() KeyBindings {
	return KeyBindings{
		General: GeneralKeyBindings{
			Quit: []string{"q", "ctrl+c"}, Help: []string{"?", "f1"},
			Refresh: []string{"r"}, Back: []string{"b", "esc"},
			Confirm: []string{"y"}, Reject: []string{"n", "esc"},
		},
		Navigation: NavigationKeyBindings{
			Down: []string{"j", "down"}, Up: []string{"k", "up"},
			Left: []string{"h", "left"}, Right: []string{"l", "right"},
			First: []string{"g"}, Last: []string{"G"},
			PageDown: []string{"ctrl+d", "pgdown"}, PageUp: []string{"ctrl+u", "pgup"},
		},
		Views: ViewKeyBindings{
			Open: []string{"enter", "l"}, Dashboard: []string{"d"},
			Health: []string{"H"}, Edit: []string{"e"}, ToggleList: []string{"tab"},
			AutoMerge: []string{"a"}, MergeNow: []string{"M"},
			AI: []string{"A"},
		},
		Threads: ThreadKeyBindings{
			Search: []string{"/"}, ClearFilter: []string{"F"},
			NextUnread: []string{"n"}, PreviousUnread: []string{"N"},
			MarkRead: []string{"m"},
			Reply:    []string{"c"}, Resolve: []string{"R"}, Toggle: []string{"enter"},
			FoldPrefix: []string{"z"}, FoldToggle: []string{"a"},
		},
		Input: InputKeyBindings{
			Cancel: []string{"esc"}, Submit: []string{"ctrl+s"}, Newline: []string{"enter"},
			DeleteBackward: []string{"backspace"}, DeleteForward: []string{"delete"},
			Clear: []string{"ctrl+u"}, NextField: []string{"tab"},
			PreviousField: []string{"shift+tab"}, NextCompletion: []string{"ctrl+n"},
			PreviousCompletion: []string{"ctrl+p"},
			LineStart:          []string{"home", "ctrl+a"}, LineEnd: []string{"end", "ctrl+e"},
		},
		Vim: VimKeyBindings{
			Insert: []string{"i"}, Append: []string{"a"},
			InsertLineStart: []string{"I"}, AppendLineEnd: []string{"A"},
			OpenBelow: []string{"o"}, OpenAbove: []string{"O"},
			ReplaceCharacter: []string{"s"}, Visual: []string{"v"}, VisualLine: []string{"V"},
			SelectionOtherEnd: []string{"o"}, Yank: []string{"y"},
			Delete: []string{"d", "x", "delete"}, DeleteBefore: []string{"X", "backspace"},
			Paste: []string{"p"}, LineStart: []string{"0", "home"},
			FirstNonBlank: []string{"^"}, LineEnd: []string{"$", "end"},
			WordForward: []string{"w"}, WORDForward: []string{"W"},
			WordBackward: []string{"b"}, WORDBackward: []string{"B"},
			WordEnd: []string{"e"}, WORDEnd: []string{"E"}, GoPrefix: []string{"g"},
			FindForward: []string{"f"}, FindBackward: []string{"F"},
			TillForward: []string{"t"}, TillBackward: []string{"T"},
			RepeatFind: []string{";"}, RepeatFindReverse: []string{","},
		},
	}
}

func keyMatches(key string, bindings []string) bool {
	for _, binding := range bindings {
		if key == binding {
			return true
		}
	}
	return false
}

func keyLabel(bindings []string) string {
	return strings.Join(bindings, " / ")
}

func primaryKeyLabel(bindings []string) string {
	if len(bindings) == 0 {
		return ""
	}
	return bindings[0]
}

func primaryCombinedKeyLabel(groups ...[]string) string {
	keys := make([]string, 0, len(groups))
	for _, group := range groups {
		if key := primaryKeyLabel(group); key != "" {
			keys = append(keys, key)
		}
	}
	return strings.Join(keys, " / ")
}

func primarySequenceKeyLabel(prefixes, suffixes []string) string {
	return primaryKeyLabel(prefixes) + primaryKeyLabel(suffixes)
}

func combinedKeyLabel(groups ...[]string) string {
	var keys []string
	for _, group := range groups {
		keys = append(keys, group...)
	}
	return keyLabel(keys)
}

func sequenceKeyLabel(prefixes, suffixes []string) string {
	var sequences []string
	for _, prefix := range prefixes {
		for _, suffix := range suffixes {
			sequences = append(sequences, prefix+suffix)
		}
	}
	return keyLabel(sequences)
}

func (k KeyBindings) canonicalHelpKey(key string) string {
	switch {
	case keyMatches(key, k.General.Quit):
		return "ctrl+c"
	case keyMatches(key, k.General.Help), keyMatches(key, k.General.Back):
		return "esc"
	case keyMatches(key, k.Navigation.Down):
		return "j"
	case keyMatches(key, k.Navigation.Up):
		return "k"
	case keyMatches(key, k.Navigation.First):
		return "g"
	case keyMatches(key, k.Navigation.Last):
		return "G"
	case keyMatches(key, k.Navigation.PageDown):
		return "ctrl+d"
	case keyMatches(key, k.Navigation.PageUp):
		return "ctrl+u"
	default:
		return ""
	}
}

func (k KeyBindings) canonicalSearchKey(key string) string {
	switch {
	case keyMatches(key, k.Input.Cancel):
		return "esc"
	case keyMatches(key, k.Input.Newline):
		return "enter"
	case keyMatches(key, k.Input.PreviousCompletion):
		return "up"
	case keyMatches(key, k.Input.NextCompletion):
		return "down"
	case keyMatches(key, k.Input.DeleteBackward):
		return "backspace"
	case keyMatches(key, k.Input.Clear):
		return "ctrl+u"
	default:
		return ""
	}
}

func (k KeyBindings) canonicalWriteKey(key string) string {
	switch {
	case keyMatches(key, k.Input.Cancel):
		return "esc"
	case keyMatches(key, k.General.Confirm):
		return "y"
	case keyMatches(key, k.General.Reject):
		return "n"
	case keyMatches(key, k.Input.Submit):
		return "ctrl+s"
	case keyMatches(key, k.Input.Newline):
		return "enter"
	case keyMatches(key, k.Input.DeleteBackward):
		return "backspace"
	default:
		return ""
	}
}

func (k KeyBindings) canonicalMainKey(key string, current screen) string {
	switch {
	case keyMatches(key, k.General.Quit):
		return "q"
	case keyMatches(key, k.General.Help):
		return "?"
	case keyMatches(key, k.General.Refresh):
		return "r"
	case keyMatches(key, k.General.Back):
		return "esc"
	case keyMatches(key, k.Navigation.Down):
		return "j"
	case keyMatches(key, k.Navigation.Up):
		return "k"
	case keyMatches(key, k.Navigation.First):
		return "g"
	case keyMatches(key, k.Navigation.Last):
		return "G"
	case keyMatches(key, k.Navigation.PageDown):
		return "ctrl+d"
	case keyMatches(key, k.Navigation.PageUp):
		return "ctrl+u"
	}
	if current == prScreen || current == dashboardScreen {
		if keyMatches(key, k.Views.Open) {
			return "enter"
		}
	}
	if current == dashboardScreen {
		switch {
		case keyMatches(key, k.Views.AutoMerge):
			return "a"
		case keyMatches(key, k.Views.MergeNow):
			return "M"
		}
	}
	if current == threadScreen {
		switch {
		case keyMatches(key, k.Navigation.Left):
			return "h"
		case keyMatches(key, k.Navigation.Right):
			return "l"
		case keyMatches(key, k.Views.ToggleList):
			return "tab"
		case keyMatches(key, k.Threads.Search):
			return "/"
		case keyMatches(key, k.Threads.ClearFilter):
			return "F"
		case keyMatches(key, k.Threads.NextUnread):
			return "n"
		case keyMatches(key, k.Threads.PreviousUnread):
			return "N"
		case keyMatches(key, k.Threads.MarkRead):
			return "m"
		case keyMatches(key, k.Threads.Reply):
			return "c"
		case keyMatches(key, k.Threads.Resolve):
			return "R"
		case keyMatches(key, k.Threads.Toggle):
			return "enter"
		case keyMatches(key, k.Threads.FoldPrefix):
			return "z"
		}
	}
	switch {
	case keyMatches(key, k.Views.Dashboard):
		return "d"
	case keyMatches(key, k.Views.Health):
		return "H"
	case keyMatches(key, k.Views.Edit):
		return "e"
	case (current == dashboardScreen || current == threadScreen) && keyMatches(key, k.Views.AI):
		return "A"
	default:
		return ""
	}
}

func (k KeyBindings) canonicalPREditKey(key string, field int, confirming bool) string {
	if confirming {
		switch {
		case keyMatches(key, k.General.Confirm):
			return "y"
		case keyMatches(key, k.General.Reject), keyMatches(key, k.Input.Cancel):
			return "esc"
		case keyMatches(key, k.Navigation.Down):
			return "down"
		case keyMatches(key, k.Navigation.Up):
			return "up"
		case keyMatches(key, k.Navigation.PageDown):
			return "ctrl+d"
		case keyMatches(key, k.Navigation.PageUp):
			return "ctrl+u"
		case keyMatches(key, k.Navigation.First):
			return "g"
		case keyMatches(key, k.Navigation.Last):
			return "G"
		}
	}
	switch {
	case keyMatches(key, k.Input.Cancel):
		return "esc"
	case keyMatches(key, k.Input.Submit):
		return "ctrl+s"
	case keyMatches(key, k.Input.NextField):
		return "tab"
	case keyMatches(key, k.Input.PreviousField):
		return "shift+tab"
	case keyMatches(key, k.Input.NextCompletion):
		return "ctrl+n"
	case keyMatches(key, k.Input.PreviousCompletion):
		return "ctrl+p"
	case keyMatches(key, k.Navigation.PageDown):
		return "ctrl+d"
	case keyMatches(key, k.Navigation.PageUp):
		return "ctrl+u"
	}
	if field != prEditBodyField {
		switch {
		case keyMatches(key, k.Input.Newline):
			return "enter"
		}
	}
	return ""
}

func validateKeyBindings(bindings KeyBindings) error {
	groups := []struct {
		name   string
		values map[string][]string
	}{
		{"keybindings.general", map[string][]string{
			"quit": bindings.General.Quit, "help": bindings.General.Help,
			"refresh": bindings.General.Refresh, "back": bindings.General.Back,
			"confirm": bindings.General.Confirm, "reject": bindings.General.Reject,
		}},
		{"keybindings.navigation", map[string][]string{
			"down": bindings.Navigation.Down, "up": bindings.Navigation.Up,
			"left": bindings.Navigation.Left, "right": bindings.Navigation.Right,
			"first": bindings.Navigation.First, "last": bindings.Navigation.Last,
			"page_down": bindings.Navigation.PageDown, "page_up": bindings.Navigation.PageUp,
		}},
		{"keybindings.views", map[string][]string{
			"open": bindings.Views.Open, "dashboard": bindings.Views.Dashboard,
			"health": bindings.Views.Health, "edit": bindings.Views.Edit,
			"auto_merge": bindings.Views.AutoMerge, "merge_now": bindings.Views.MergeNow,
			"toggle_list": bindings.Views.ToggleList,
			"ai":          bindings.Views.AI,
		}},
		{"keybindings.threads", map[string][]string{
			"search": bindings.Threads.Search, "clear_filter": bindings.Threads.ClearFilter,
			"next_unread":     bindings.Threads.NextUnread,
			"previous_unread": bindings.Threads.PreviousUnread,
			"mark_read":       bindings.Threads.MarkRead,
			"reply":           bindings.Threads.Reply, "resolve": bindings.Threads.Resolve,
			"toggle": bindings.Threads.Toggle, "fold_prefix": bindings.Threads.FoldPrefix,
			"fold_toggle": bindings.Threads.FoldToggle,
		}},
		{"keybindings.input", map[string][]string{
			"cancel": bindings.Input.Cancel,
			"submit": bindings.Input.Submit, "newline": bindings.Input.Newline,
			"delete_backward": bindings.Input.DeleteBackward,
			"delete_forward":  bindings.Input.DeleteForward, "clear": bindings.Input.Clear,
			"next_field": bindings.Input.NextField, "previous_field": bindings.Input.PreviousField,
			"next_completion":     bindings.Input.NextCompletion,
			"previous_completion": bindings.Input.PreviousCompletion,
			"line_start":          bindings.Input.LineStart, "line_end": bindings.Input.LineEnd,
		}},
		{"keybindings.vim", map[string][]string{
			"insert": bindings.Vim.Insert, "append": bindings.Vim.Append,
			"insert_line_start": bindings.Vim.InsertLineStart,
			"append_line_end":   bindings.Vim.AppendLineEnd,
			"open_below":        bindings.Vim.OpenBelow, "open_above": bindings.Vim.OpenAbove,
			"replace_character": bindings.Vim.ReplaceCharacter,
			"visual":            bindings.Vim.Visual, "visual_line": bindings.Vim.VisualLine,
			"selection_other_end": bindings.Vim.SelectionOtherEnd,
			"yank":                bindings.Vim.Yank, "delete": bindings.Vim.Delete,
			"delete_before": bindings.Vim.DeleteBefore, "paste": bindings.Vim.Paste,
			"line_start":      bindings.Vim.LineStart,
			"first_non_blank": bindings.Vim.FirstNonBlank, "line_end": bindings.Vim.LineEnd,
			"word_forward": bindings.Vim.WordForward, "big_word_forward": bindings.Vim.WORDForward,
			"word_backward": bindings.Vim.WordBackward, "big_word_backward": bindings.Vim.WORDBackward,
			"word_end": bindings.Vim.WordEnd, "big_word_end": bindings.Vim.WORDEnd,
			"go_prefix":    bindings.Vim.GoPrefix,
			"find_forward": bindings.Vim.FindForward, "find_backward": bindings.Vim.FindBackward,
			"till_forward": bindings.Vim.TillForward, "till_backward": bindings.Vim.TillBackward,
			"repeat_find":         bindings.Vim.RepeatFind,
			"repeat_find_reverse": bindings.Vim.RepeatFindReverse,
		}},
	}
	for _, group := range groups {
		for action, keys := range group.values {
			if len(keys) == 0 {
				return fmt.Errorf("%s.%s must contain at least one key", group.name, action)
			}
			seen := make(map[string]bool)
			for _, key := range keys {
				if strings.TrimSpace(key) == "" {
					return fmt.Errorf("%s.%s contains an empty key", group.name, action)
				}
				if seen[key] {
					return fmt.Errorf("%s.%s contains duplicate key %q", group.name, action, key)
				}
				seen[key] = true
			}
		}
	}
	return validateKeyBindingContexts(bindings)
}

type contextBinding struct {
	action string
	keys   []string
}

func validateKeyBindingContexts(bindings KeyBindings) error {
	navigation := bindings.Navigation
	general := bindings.General
	views := bindings.Views
	threads := bindings.Threads
	input := bindings.Input
	vim := bindings.Vim

	screenCommon := []contextBinding{
		{"quit", general.Quit}, {"help", general.Help}, {"refresh", general.Refresh},
		{"back", general.Back}, {"down", navigation.Down}, {"up", navigation.Up},
		{"first", navigation.First}, {"last", navigation.Last},
		{"page_down", navigation.PageDown}, {"page_up", navigation.PageUp},
		{"health", views.Health},
	}
	if err := validateKeyContext("pull request list", append(screenCommon,
		contextBinding{"open", views.Open},
		contextBinding{"dashboard", views.Dashboard},
	)...); err != nil {
		return err
	}
	if err := validateKeyContext("dashboard", append(screenCommon,
		contextBinding{"open", views.Open},
		contextBinding{"edit", views.Edit},
		contextBinding{"auto_merge", views.AutoMerge},
		contextBinding{"merge_now", views.MergeNow},
		contextBinding{"ai", views.AI},
	)...); err != nil {
		return err
	}
	if err := validateKeyContext("health screen", screenCommon...); err != nil {
		return err
	}
	if err := validateKeyContext("review threads", append(screenCommon,
		contextBinding{"left", navigation.Left},
		contextBinding{"right", navigation.Right},
		contextBinding{"toggle_list", views.ToggleList},
		contextBinding{"dashboard", views.Dashboard},
		contextBinding{"search", threads.Search},
		contextBinding{"clear_filter", threads.ClearFilter},
		contextBinding{"next_unread", threads.NextUnread},
		contextBinding{"previous_unread", threads.PreviousUnread},
		contextBinding{"mark_read", threads.MarkRead},
		contextBinding{"reply", threads.Reply},
		contextBinding{"resolve", threads.Resolve},
		contextBinding{"toggle", threads.Toggle},
		contextBinding{"fold_prefix", threads.FoldPrefix},
		contextBinding{"ai", views.AI},
	)...); err != nil {
		return err
	}
	if err := validateKeyContext("help popup",
		contextBinding{"quit", general.Quit},
		contextBinding{"close_help", appendCopy(general.Help, general.Back...)},
		contextBinding{"down", navigation.Down},
		contextBinding{"up", navigation.Up},
		contextBinding{"first", navigation.First},
		contextBinding{"last", navigation.Last},
		contextBinding{"page_down", navigation.PageDown},
		contextBinding{"page_up", navigation.PageUp},
	); err != nil {
		return err
	}

	if err := validateKeyContext("search input",
		contextBinding{"quit", nonTextBindings(general.Quit)},
		contextBinding{"cancel", input.Cancel},
		contextBinding{"apply", input.Newline},
		contextBinding{"previous_completion", input.PreviousCompletion},
		contextBinding{"next_completion", input.NextCompletion},
		contextBinding{"delete_backward", input.DeleteBackward},
		contextBinding{"delete_forward", input.DeleteForward},
		contextBinding{"clear", input.Clear},
		contextBinding{"line_start", input.LineStart},
		contextBinding{"line_end", input.LineEnd},
		contextBinding{"left", nonTextBindings(navigation.Left)},
		contextBinding{"right", nonTextBindings(navigation.Right)},
	); err != nil {
		return err
	}
	if err := validateKeyContext("reply input",
		contextBinding{"quit", nonTextBindings(general.Quit)},
		contextBinding{"cancel", input.Cancel},
		contextBinding{"submit", input.Submit},
		contextBinding{"newline", input.Newline},
		contextBinding{"delete_backward", input.DeleteBackward},
		contextBinding{"delete_forward", input.DeleteForward},
		contextBinding{"line_start", input.LineStart},
		contextBinding{"line_end", input.LineEnd},
		contextBinding{"left", nonTextBindings(navigation.Left)},
		contextBinding{"down", nonTextBindings(navigation.Down)},
		contextBinding{"up", nonTextBindings(navigation.Up)},
		contextBinding{"right", nonTextBindings(navigation.Right)},
	); err != nil {
		return err
	}
	if err := validateKeyContext("confirmation",
		contextBinding{"quit", nonTextBindings(general.Quit)},
		contextBinding{"confirm", general.Confirm},
		contextBinding{"cancel", appendCopy(general.Reject, input.Cancel...)},
	); err != nil {
		return err
	}
	if err := validateKeyContext("AI menu",
		contextBinding{"quit", nonTextBindings(general.Quit)},
		contextBinding{"cancel", appendCopy(general.Back, input.Cancel...)},
		contextBinding{"down", navigation.Down},
		contextBinding{"up", navigation.Up},
		contextBinding{"select", appendCopy(views.Open, input.Newline...)},
	); err != nil {
		return err
	}
	if err := validateKeyContext("AI confirmation",
		contextBinding{"quit", nonTextBindings(general.Quit)},
		contextBinding{"confirm", general.Confirm},
		contextBinding{"cancel", appendCopy(general.Reject, input.Cancel...)},
		contextBinding{"down", navigation.Down},
		contextBinding{"up", navigation.Up},
		contextBinding{"page_down", navigation.PageDown},
		contextBinding{"page_up", navigation.PageUp},
	); err != nil {
		return err
	}

	editorOuter := []contextBinding{
		{"help", general.Help},
		{"cancel", input.Cancel},
		{"submit", input.Submit},
		{"next_field", input.NextField},
		{"previous_field", input.PreviousField},
		{"page_down", navigation.PageDown},
		{"page_up", navigation.PageUp},
	}
	normalEditor := append(append([]contextBinding(nil), editorOuter...),
		contextBinding{"left", navigation.Left},
		contextBinding{"down", navigation.Down},
		contextBinding{"up", navigation.Up},
		contextBinding{"right", navigation.Right},
		contextBinding{"last", navigation.Last},
		contextBinding{"insert", vim.Insert},
		contextBinding{"append", vim.Append},
		contextBinding{"insert_line_start", vim.InsertLineStart},
		contextBinding{"append_line_end", vim.AppendLineEnd},
		contextBinding{"open_below", vim.OpenBelow},
		contextBinding{"open_above", vim.OpenAbove},
		contextBinding{"replace_character", vim.ReplaceCharacter},
		contextBinding{"visual", vim.Visual},
		contextBinding{"visual_line", vim.VisualLine},
		contextBinding{"paste", vim.Paste},
		contextBinding{"line_start", vim.LineStart},
		contextBinding{"first_non_blank", vim.FirstNonBlank},
		contextBinding{"line_end", vim.LineEnd},
		contextBinding{"word_forward", vim.WordForward},
		contextBinding{"big_word_forward", vim.WORDForward},
		contextBinding{"word_backward", vim.WordBackward},
		contextBinding{"big_word_backward", vim.WORDBackward},
		contextBinding{"word_end", vim.WordEnd},
		contextBinding{"big_word_end", vim.WORDEnd},
		contextBinding{"go_prefix", vim.GoPrefix},
		contextBinding{"find_forward", vim.FindForward},
		contextBinding{"find_backward", vim.FindBackward},
		contextBinding{"till_forward", vim.TillForward},
		contextBinding{"till_backward", vim.TillBackward},
		contextBinding{"repeat_find", vim.RepeatFind},
		contextBinding{"repeat_find_reverse", vim.RepeatFindReverse},
		contextBinding{"delete", vim.Delete},
		contextBinding{"delete_before", vim.DeleteBefore},
	)
	if err := validateKeyContext("Vim Normal mode", normalEditor...); err != nil {
		return err
	}
	visualEditor := append(append([]contextBinding(nil), editorOuter...),
		contextBinding{"left", navigation.Left},
		contextBinding{"down", navigation.Down},
		contextBinding{"up", navigation.Up},
		contextBinding{"right", navigation.Right},
		contextBinding{"last", navigation.Last},
		contextBinding{"visual", vim.Visual},
		contextBinding{"visual_line", vim.VisualLine},
		contextBinding{"selection_other_end", vim.SelectionOtherEnd},
		contextBinding{"yank", vim.Yank},
		contextBinding{"delete", vim.Delete},
		contextBinding{"substitute", vim.ReplaceCharacter},
		contextBinding{"paste", vim.Paste},
		contextBinding{"line_start", vim.LineStart},
		contextBinding{"first_non_blank", vim.FirstNonBlank},
		contextBinding{"line_end", vim.LineEnd},
		contextBinding{"word_forward", vim.WordForward},
		contextBinding{"big_word_forward", vim.WORDForward},
		contextBinding{"word_backward", vim.WordBackward},
		contextBinding{"big_word_backward", vim.WORDBackward},
		contextBinding{"word_end", vim.WordEnd},
		contextBinding{"big_word_end", vim.WORDEnd},
		contextBinding{"go_prefix", vim.GoPrefix},
		contextBinding{"find_forward", vim.FindForward},
		contextBinding{"find_backward", vim.FindBackward},
		contextBinding{"till_forward", vim.TillForward},
		contextBinding{"till_backward", vim.TillBackward},
		contextBinding{"repeat_find", vim.RepeatFind},
		contextBinding{"repeat_find_reverse", vim.RepeatFindReverse},
	)
	if err := validateKeyContext("Vim Visual mode", visualEditor...); err != nil {
		return err
	}
	insertEditor := append(append([]contextBinding(nil), editorOuter...),
		contextBinding{"left", nonTextBindings(navigation.Left)},
		contextBinding{"down", nonTextBindings(navigation.Down)},
		contextBinding{"up", nonTextBindings(navigation.Up)},
		contextBinding{"right", nonTextBindings(navigation.Right)},
		contextBinding{"newline", input.Newline},
		contextBinding{"delete_backward", input.DeleteBackward},
		contextBinding{"delete_forward", input.DeleteForward},
		contextBinding{"line_start", input.LineStart},
		contextBinding{"line_end", input.LineEnd},
	)
	if err := validateKeyContext("editor Insert mode", insertEditor...); err != nil {
		return err
	}
	return validateKeyContext("single-line editor input",
		contextBinding{"help", nonTextBindings(general.Help)},
		contextBinding{"cancel", input.Cancel},
		contextBinding{"submit", input.Submit},
		contextBinding{"next_field", input.NextField},
		contextBinding{"previous_field", input.PreviousField},
		contextBinding{"previous_completion", input.PreviousCompletion},
		contextBinding{"next_completion", input.NextCompletion},
		contextBinding{"newline", input.Newline},
		contextBinding{"delete_backward", input.DeleteBackward},
		contextBinding{"delete_forward", input.DeleteForward},
		contextBinding{"line_start", input.LineStart},
		contextBinding{"line_end", input.LineEnd},
		contextBinding{"left", nonTextBindings(navigation.Left)},
		contextBinding{"right", nonTextBindings(navigation.Right)},
		contextBinding{"up", nonTextBindings(navigation.Up)},
		contextBinding{"down", nonTextBindings(navigation.Down)},
	)
}

func validateKeyContext(context string, bindings ...contextBinding) error {
	assigned := make(map[string]string)
	for _, binding := range bindings {
		for _, key := range binding.keys {
			if previous, exists := assigned[key]; exists && previous != binding.action {
				return fmt.Errorf(
					"keybinding conflict in %s: key %q is assigned to both %s and %s",
					context, key, previous, binding.action,
				)
			}
			assigned[key] = binding.action
		}
	}
	return nil
}

func nonTextBindings(bindings []string) []string {
	var filtered []string
	for _, binding := range bindings {
		if utf8.RuneCountInString(binding) != 1 {
			filtered = append(filtered, binding)
		}
	}
	return filtered
}

func appendCopy(bindings []string, more ...string) []string {
	result := append([]string(nil), bindings...)
	return append(result, more...)
}