package main

// What the tools show of the five kinds (novox/hq ADR 0329 §1, §11–§13): the profile's entries beside the declared
// ones, with the operator's own values, and how a node differs from what is declared. Never a credential (§2):
// every answer passes credentialChecked, which withholds a field whose name says password, token, secret or cookie
// and the password part of any address.

import (
	"encoding/json"
	"fmt"
	"strings"
)

// configView is the profile and the settings, read once for an answer.
type configView struct {
	p        Profile
	prefs    map[string]string
	accounts map[string]Account
	ra       []resolvedAccount
	conf     Configuration
	problem  string
	plan     configPlan
	rec      configRecord
}

func (m *Machine) view() (configView, error) {
	var v configView
	p, err := m.profile()
	if err != nil {
		return v, err
	}
	v.p, v.prefs = p, mergedPrefs(p.path)
	accounts, _, aerr := m.readAccounts()
	if aerr != nil {
		v.problem = aerr.Error()
	}
	v.accounts = accounts
	v.ra = resolveAccounts(accounts, v.prefs, m.readRecord(p.Dir))
	conf, cerr := m.readConfiguration()
	if cerr != nil {
		v.problem = strings.TrimPrefix(v.problem+"; "+cerr.Error(), "; ")
	}
	v.conf = conf
	v.rec = m.readConfigRecord(p.Dir)
	v.plan = m.planConfiguration(p, conf, accounts, v.ra, v.prefs)
	return v, nil
}

// listedEntry is one entry of the profile, with its values: Owl's marked, an ICS calendar by its name only (§13).
type listedEntry struct {
	Key  string `json:"key"`
	Kind string `json:"kind,omitempty"`
	// Account is an identity's account key in the profile, or the account name filters are listed under.
	Account string `json:"account,omitempty"`
	Owl     bool   `json:"owl,omitempty"`
	// DeclaredAs is the declared entry this one is, or empty: the person's own.
	DeclaredAs string `json:"declared_as,omitempty"`
	Value      any    `json:"value,omitempty"`
	Note       string `json:"note,omitempty"`
}

// declaredEntry is one declared entry, its value and how it resolved on this node.
type declaredEntry struct {
	Name  string `json:"name"`
	Value any    `json:"value"`
	How   string `json:"how,omitempty"`
	Key   string `json:"key,omitempty"`
	Why   string `json:"why,omitempty"`
}

// KindListing is what a listing tool answers.
type KindListing struct {
	Profile   string          `json:"profile"`
	Kind      string          `json:"kind"`
	InProfile []listedEntry   `json:"in_the_profile"`
	Declared  []declaredEntry `json:"declared"`
	// Kept says where the module keeps the filter files it replaced, per account (§8).
	Kept    map[string]string `json:"kept_filter_files,omitempty"`
	Problem string            `json:"problem,omitempty"`
}

func (v configView) resolved(kind string) map[string]resolvedEntry {
	out := map[string]resolvedEntry{}
	for _, e := range v.plan.Entries {
		if e.Kind == kind {
			out[e.Name] = e
		}
	}
	return out
}

// declaredBy is, per profile key, the declared entry of a kind adopted or created under it.
func (v configView) declaredBy(kind string) map[string]string {
	out := map[string]string{}
	for _, e := range v.plan.Entries {
		if e.Kind == kind && e.How != refused {
			out[e.Key] = e.Name
		}
	}
	return out
}

// List answers one kind: the profile's entries beside the declared ones.
func (m *Machine) List(kind string) (KindListing, error) {
	v, err := m.view()
	a := KindListing{Kind: kind, InProfile: []listedEntry{}, Declared: []declaredEntry{}}
	if err != nil {
		return a, err
	}
	a.Profile, a.Problem = v.p.Dir, v.problem
	res := v.resolved(kind)
	by := v.declaredBy(kind)
	declare := func(name string, value any) {
		r := res[name]
		a.Declared = append(a.Declared, declaredEntry{Name: name, Value: value, How: r.How, Key: r.Key, Why: r.Why})
	}
	switch kind {
	case kindIdentities:
		for _, pi := range m.profileIdentities(v.prefs) {
			a.InProfile = append(a.InProfile, listedEntry{Key: pi.Key, Account: pi.AccountKey, Owl: pi.Owl,
				DeclaredAs: by[pi.Key], Value: pi.Value})
		}
		for _, name := range sortedKeys(v.conf.Identities) {
			declare(name, v.conf.Identities[name])
		}
	case kindCalendars:
		for _, pc := range profileCalendars(v.prefs) {
			e := listedEntry{Key: pc.Key, Kind: pc.Kind, DeclaredAs: by[pc.Key], Value: pc.Value}
			switch {
			case strings.HasPrefix(pc.Kind, "owl"):
				e.Owl, e.Value = true, map[string]string{"name": pc.Value.Name, "url": pc.Value.URL}
				e.Note = "Owl's: never declared (novox/hq ADR 0316 §13)"
			case pc.Kind == "ics":
				e.Value = map[string]string{"name": pc.Value.Name}
				e.Note = "subscribed by an ICS address, which is often itself the secret: its name only, never declared (novox/hq ADR 0329 §13)"
			case pc.Kind != "caldav":
				e.Note = "kept in the profile: its events are never declared"
			}
			a.InProfile = append(a.InProfile, e)
		}
		for _, name := range sortedKeys(v.conf.Calendars) {
			declare(name, v.conf.Calendars[name])
		}
	case kindAddressBooks:
		for _, b := range profileAddressBooks(v.prefs) {
			e := listedEntry{Key: b.Key, Kind: b.Kind, DeclaredAs: by[b.Key], Value: b.Value}
			if !b.CardDAV {
				e.Value, e.Note = map[string]string{"name": b.Value.Name}, "its contacts are kept in the profile and never declared"
			}
			a.InProfile = append(a.InProfile, e)
		}
		for _, name := range sortedKeys(v.conf.AddressBooks) {
			declare(name, v.conf.AddressBooks[name])
		}
	case kindTags:
		for _, t := range profileTags(v.prefs) {
			a.InProfile = append(a.InProfile, listedEntry{Key: t.Key, DeclaredAs: by[t.Key], Value: t.Value})
		}
		for _, key := range sortedKeys(v.conf.Tags) {
			declare(key, v.conf.Tags[key])
		}
	case kindFilters:
		for _, f := range m.profileFilters(v) {
			a.InProfile = append(a.InProfile, f)
		}
		for _, account := range v.conf.sortedFilterAccounts() {
			d := declaredEntry{Name: account, Value: v.conf.Filters[account], How: "owned whole"}
			for _, fp := range v.plan.filters {
				if fp.Account == account {
					d.Key, d.Why = fp.File, strings.TrimSpace(fp.Refused+" "+fp.Waiting)
					if fp.Refused != "" {
						d.How = refused
					}
				}
			}
			a.Declared = append(a.Declared, d)
		}
		a.Kept = map[string]string{}
		for _, account := range sortedKeys(v.rec.Filters) {
			if r := v.rec.Filters[account]; r.Kept != "" {
				a.Kept[account] = r.Kept
			}
		}
		if len(a.Kept) == 0 {
			a.Kept = nil
		}
	default:
		return a, fmt.Errorf("a kind is one of %s", strings.Join(allKinds, ", "))
	}
	return a, nil
}

// profileFilters are the filters of each declared account in the profile, by the account's name.
func (m *Machine) profileFilters(v configView) []listedEntry {
	var out []listedEntry
	for _, r := range v.ra {
		if r.How == refused {
			continue
		}
		dir := m.accountDirectory(v.p.path, v.prefs, r.Keys.Server)
		if dir == "" {
			continue
		}
		text, err := readBounded(dir + "/" + filterFileName)
		if err != nil {
			continue
		}
		parsed := parseFilters(string(text), folderBase(v.prefs, r.Keys.Server))
		e := listedEntry{Key: m.tilde(strings.TrimPrefix(dir+"/"+filterFileName, m.Root)), Account: r.name, Value: parsed.Filters}
		if _, declared := v.conf.Filters[r.name]; declared {
			e.DeclaredAs = r.name
		}
		if len(parsed.NotDeclarable) > 0 {
			e.Note = "not declarable as they are: " + strings.Join(parsed.NotDeclarable, "; ")
		}
		out = append(out, e)
	}
	return out
}

// fieldDiff is one field a profile holds differently from the declared value.
type fieldDiff struct {
	Field    string `json:"field"`
	Declared any    `json:"declared"`
	Profile  any    `json:"profile"`
}

// DriftEntry is one declared entry against the profile: holds, differs, lacks or refused (§11).
type DriftEntry struct {
	Name    string      `json:"name"`
	State   string      `json:"state"`
	Key     string      `json:"key,omitempty"`
	Differs []fieldDiff `json:"differs,omitempty"`
	Why     string      `json:"why,omitempty"`
}

// KindDrift is one kind's drift, and the profile's entries nothing declares.
type KindDrift struct {
	Kind       string        `json:"kind"`
	Declared   []DriftEntry  `json:"declared"`
	Undeclared []listedEntry `json:"undeclared,omitempty"`
}

// DriftAnswer is what betterbird_drift answers.
type DriftAnswer struct {
	Profile string      `json:"profile"`
	Kinds   []KindDrift `json:"kinds"`
	Note    string      `json:"note"`
	Problem string      `json:"problem,omitempty"`
}

// Drift answers, per kind, how the profile differs from what is declared: the profile as Betterbird reads it at
// its next start (prefs.js with user.js over it), so a declared value the module placed and Betterbird has not
// started with yet holds; the drift then is only what the module did not place.
func (m *Machine) Drift(kind string) (DriftAnswer, error) {
	v, err := m.view()
	a := DriftAnswer{Kinds: []KindDrift{}}
	if err != nil {
		return a, err
	}
	a.Profile, a.Problem = v.p.Dir, v.problem
	a.Note = "the profile as Betterbird reads it at its next start (prefs.js, the module's user.js over it): differs " +
		"names each field with the declared value and the profile's; lacks is an entry the profile does not hold yet " +
		"(betterbird_user_js with apply, betterbird_restart); undeclared entries stay the person's"
	kinds := allKinds
	if kind != "" {
		if !contains(allKinds, kind) {
			return a, fmt.Errorf("a kind is one of %s", strings.Join(allKinds, ", "))
		}
		kinds = []string{kind}
	}
	for _, k := range kinds {
		a.Kinds = append(a.Kinds, m.kindDrift(v, k))
	}
	return a, nil
}

func (m *Machine) kindDrift(v configView, kind string) KindDrift {
	d := KindDrift{Kind: kind, Declared: []DriftEntry{}}
	res := v.resolved(kind)
	by := v.declaredBy(kind)
	entry := func(name string, declared any, profile func(key string) (any, bool)) {
		r := res[name]
		e := DriftEntry{Name: name, Key: r.Key}
		switch {
		case r.How == refused:
			e.State, e.Why = refused, r.Why
		default:
			have, ok := profile(r.Key)
			if !ok {
				e.State = "lacks"
				break
			}
			e.Differs = differing(declared, have)
			e.State = map[bool]string{true: "holds", false: "differs"}[len(e.Differs) == 0]
		}
		d.Declared = append(d.Declared, e)
	}
	switch kind {
	case kindIdentities:
		ids := map[string]profileIdentity{}
		for _, pi := range m.profileIdentities(v.prefs) {
			ids[pi.Key] = pi
			if by[pi.Key] == "" && !pi.Owl {
				d.Undeclared = append(d.Undeclared, listedEntry{Key: pi.Key, Account: pi.AccountKey, Value: pi.Value})
			}
		}
		for _, name := range sortedKeys(v.conf.Identities) {
			want := *v.conf.Identities[name]
			want.Key = ""
			entry(name, want, func(key string) (any, bool) {
				pi, ok := ids[key]
				if !ok {
					return nil, false
				}
				have := pi.Value
				have.Account = want.Account
				if want.Address == "" {
					have.Address, have.Name = "", ""
				}
				return have, true
			})
		}
	case kindCalendars:
		cals := map[string]profileCalendar{}
		for _, pc := range profileCalendars(v.prefs) {
			cals[pc.Key] = pc
			if by[pc.Key] == "" && pc.Kind == "caldav" {
				d.Undeclared = append(d.Undeclared, listedEntry{Key: pc.Key, Kind: pc.Kind, Value: pc.Value})
			}
		}
		idName := v.declaredBy(kindIdentities)
		for _, name := range sortedKeys(v.conf.Calendars) {
			want := *v.conf.Calendars[name]
			want.Key = ""
			entry(name, want, func(key string) (any, bool) {
				pc, ok := cals[key]
				if !ok {
					return nil, false
				}
				have := pc.Value
				have.Invitations = idName[pc.IdentityKey]
				if have.Reminders == nil && want.Reminders != nil && *want.Reminders {
					on := true
					have.Reminders = &on
				}
				return have, true
			})
		}
	case kindAddressBooks:
		books := map[string]profileAddressBook{}
		for _, b := range profileAddressBooks(v.prefs) {
			books[b.Key] = b
			if by[b.Key] == "" && b.CardDAV {
				d.Undeclared = append(d.Undeclared, listedEntry{Key: b.Key, Kind: b.Kind, Value: b.Value})
			}
		}
		for _, name := range sortedKeys(v.conf.AddressBooks) {
			want := *v.conf.AddressBooks[name]
			want.Key = ""
			entry(name, want, func(key string) (any, bool) {
				b, ok := books[key]
				return b.Value, ok
			})
		}
	case kindTags:
		tags := map[string]profileTag{}
		for _, t := range profileTags(v.prefs) {
			tags[t.Key] = t
			if by[t.Key] == "" {
				d.Undeclared = append(d.Undeclared, listedEntry{Key: t.Key, Value: t.Value})
			}
		}
		for _, key := range sortedKeys(v.conf.Tags) {
			want := *v.conf.Tags[key]
			entry(key, want, func(k string) (any, bool) {
				t, ok := tags[k]
				have := t.Value
				if want.Order == 0 {
					have.Order = 0
				}
				return have, ok
			})
		}
	case kindFilters:
		files := map[string]listedEntry{}
		for _, f := range m.profileFilters(v) {
			files[f.Account] = f
			released := v.rec.Filters[f.Account].Released
			if f.DeclaredAs == "" && !released {
				if list, _ := f.Value.([]Filter); len(list) > 0 {
					d.Undeclared = append(d.Undeclared, f)
				}
			}
		}
		for _, fp := range v.plan.filters {
			e := DriftEntry{Name: fp.Account, Key: fp.File}
			switch {
			case fp.Refused != "":
				e.State, e.Why = refused, fp.Refused
			case fp.path == "" || !fp.exists:
				e.State, e.Why = "lacks", strings.TrimSpace(fp.Waiting)
			default:
				have, _ := files[fp.Account].Value.([]Filter)
				for _, line := range filterDifferences(v.conf.Filters[fp.Account], have) {
					e.Differs = append(e.Differs, fieldDiff{Field: line})
				}
				if fp.have != fp.want && len(e.Differs) == 0 {
					e.Differs = append(e.Differs, fieldDiff{Field: "the file's text, beyond the filters' own words"})
				}
				e.State = map[bool]string{true: "holds", false: "differs"}[len(e.Differs) == 0]
			}
			d.Declared = append(d.Declared, e)
		}
	}
	return d
}

// differing are the fields of two values of the same shape that differ.
func differing(declared, have any) []fieldDiff {
	var a, b map[string]any
	_ = json.Unmarshal([]byte(mustJSON(declared)), &a)
	_ = json.Unmarshal([]byte(mustJSON(have)), &b)
	var out []fieldDiff
	for _, f := range sortedKeys(mergeKeys(a, b)) {
		if mustJSON(a[f]) != mustJSON(b[f]) {
			out = append(out, fieldDiff{Field: f, Declared: a[f], Profile: b[f]})
		}
	}
	return out
}

// driftCounts are, per kind, how many declared entries do not hold.
func (m *Machine) driftCounts(v configView) map[string]int {
	out := map[string]int{}
	for _, k := range allKinds {
		for _, e := range m.kindDrift(v, k).Declared {
			if e.State != "holds" {
				out[k]++
			}
		}
	}
	return out
}

// credentialChecked is an answer as it may leave the tool (§2): a field whose name says password, token, secret
// or cookie withheld, and the password part of any address as ‹withheld›.
func credentialChecked(v any) any {
	b, err := json.Marshal(v)
	if err != nil {
		return v
	}
	var tree any
	if json.Unmarshal(b, &tree) != nil {
		return v
	}
	return scrubTree(tree)
}

func scrubTree(n any) any {
	switch x := n.(type) {
	case map[string]any:
		for k, v := range x {
			if secretName.MatchString(k) {
				x[k] = "‹withheld›"
				continue
			}
			x[k] = scrubTree(v)
		}
		return x
	case []any:
		for i, v := range x {
			x[i] = scrubTree(v)
		}
		return x
	case string:
		return withoutPassword(x)
	}
	return n
}