package approval

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

// The mesh MCP server's mesh_approvals reads and steers what the gate asked on this machine (§18).

// Listed is one ask of the last day as mesh_approvals lists it: its state and its act's fingerprint.
type Listed struct {
	Ask         string    `json:"ask"`
	Address     string    `json:"address"`
	Module      string    `json:"module"`
	Asked       time.Time `json:"asked"`
	State       string    `json:"state"`
	Fingerprint string    `json:"fingerprint"`
}

// Whole is one ask read whole: its arguments and the act's digest.
type Whole struct {
	Listed
	Digest    string            `json:"digest"`
	Act       map[string]string `json:"act"`
	Arguments json.RawMessage   `json:"arguments"`
	Recorded  bool              `json:"recorded"`
}

// stateOf is a kept ask's state as the runner knows it.
func stateOf(acted, recorded bool, ended string) string {
	switch {
	case acted && recorded:
		return "run, recorded"
	case acted:
		return "run, not yet recorded"
	case ended != "":
		return ended
	}
	return "asked"
}

// List is the calls asked on this machine in the last day, newest first (§18).
func (g *Gate) List() ([]Listed, error) {
	if g.d.State == nil {
		return nil, fmt.Errorf("the tool runner's membership binds no state %s", StateName)
	}
	keys, err := g.d.State.Keys()
	if err != nil {
		return nil, err
	}
	prefix := g.d.Node + ".ask."
	out := []Listed{}
	for _, key := range keys {
		if !strings.HasPrefix(key, prefix) {
			continue
		}
		w, err := g.Read(strings.TrimPrefix(key, prefix))
		if err != nil || g.d.Now().Sub(w.Asked) > 24*time.Hour {
			continue
		}
		out = append(out, w.Listed)
	}
	sort.Slice(out, func(i, j int) bool { return out[i].Asked.After(out[j].Asked) })
	return out, nil
}

// Read is one ask whole: its arguments and the act's digest (§18).
func (g *Gate) Read(id string) (Whole, error) {
	if g.d.State == nil {
		return Whole{}, fmt.Errorf("the tool runner's membership binds no state %s", StateName)
	}
	k, _, err := g.kept(id)
	if err != nil {
		return Whole{}, err
	}
	if k == nil {
		return Whole{}, fmt.Errorf("no ask %s is kept on %s", id, g.d.Node)
	}
	module := k.Act["module"]
	if module == "" {
		module = moduleOf(k)
	}
	var ask struct {
		About string `json:"about"`
	}
	_ = json.Unmarshal(k.Ask, &ask)
	return Whole{Listed: Listed{Ask: id, Address: k.Act["address"], Module: module, Asked: k.Asked,
		State: stateOf(k.Acted, k.Recorded, k.Ended), Fingerprint: Fingerprint(ask.About)},
		Digest: ask.About, Act: k.Act, Arguments: k.Arguments, Recorded: k.Recorded}, nil
}

// Applied are the marks the gate applies on this machine, each module's marked tools and verbs with their source and the
// catalog revision read (§18).
func (g *Gate) Applied() []Marks {
	g.mu.Lock()
	modules := make([]string, 0, len(g.served))
	for m := range g.served {
		modules = append(modules, m)
	}
	g.mu.Unlock()
	sort.Strings(modules)
	var out []Marks
	if g.d.Catalog == nil {
		return out
	}
	for _, m := range modules {
		if marks := Derive(g.d.Catalog, m, g.servedFingerprint(m)); marks.Any() {
			out = append(out, marks)
		}
	}
	return out
}

func (g *Gate) servedFingerprint(module string) string {
	g.mu.Lock()
	defer g.mu.Unlock()
	return g.served[module]
}

// Describe says whether a tool or a seat verb of a module is marked, and its source, for mesh_describe (§18): the served
// build's marks where this machine serves the module, else the newest entry's and its seat's.
func (g *Gate) Describe(module, seat, name string) (bool, string) {
	if g.d.Catalog == nil || g.d.Catalog.Ready() != nil {
		return false, ""
	}
	if seat != "" && module == "" {
		for s, d := range g.d.Catalog.Definitions() {
			if s != seat {
				continue
			}
			for _, v := range d.Verbs {
				if v.Name == name && v.NeedsApproval {
					return true, "seat " + seat
				}
			}
		}
		return false, ""
	}
	return Derive(g.d.Catalog, module, g.servedFingerprint(module)).Marked(seat, name)
}

// Again asks `warranted` again for one acted, unrecorded ask, by hand, in the kept-call form of §16 (§18); the caller
// records the hand act first.
func (g *Gate) Again(id string) error {
	w, err := g.Read(id)
	if err != nil {
		return err
	}
	if !strings.HasPrefix(w.State, "run, not yet") {
		return fmt.Errorf("the ask %s is %s: only a run not yet recorded is asked again", id, w.State)
	}
	g.recordRun(w.Module, id)
	if again, _ := g.Read(id); !again.Recorded {
		return fmt.Errorf("mesh-hand-acts.warranted has not answered for ask %s yet", id)
	}
	return nil
}

// Cancel takes an open ask back through operator-channel's client (§18); the caller records the hand act first.
func (g *Gate) Cancel(id string) error {
	w, err := g.Read(id)
	if err != nil {
		return err
	}
	if w.State != "asked" {
		return fmt.Errorf("the ask %s is %s, not open", id, w.State)
	}
	return g.d.Channel.Cancel(w.Module, id)
}