package main

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"strings"

	hexisclient "github.com/kami/hexis/pkg/client"
	"github.com/kami/maven/internal/ipc"
	"github.com/kami/maven/internal/router"
)

// praxisCapability is one arm of the Praxis act dispatch. This is an interface
// rather than a map[string]func because each arm carries its own state: the
// verb aliases it answers to, the trace name it records, and its own reply
// formatting. The dispatch grows an arm per Praxis capability, so a new one is
// added to praxisCapabilities below and nothing else changes.
type praxisCapability interface {
	// aliases are the verbs (router fn slots, EN and RU) this capability answers to.
	aliases() []string
	// handle runs the capability and returns the user-facing reply.
	handle(ctx context.Context, h *reactiveHandler, px *praxisClient, dec router.Decision) string
}

// praxisCapabilities is the registry handlePraxisAct consults, in order.
var praxisCapabilities = []praxisCapability{
	listAttentionCapability{},
	praxisItemAction{
		verbs:   []string{"acknowledge_item", "принято", "понял", "поняла"},
		ask:     "какой пункт отметить принятым?",
		op:      "acknowledge",
		failure: "не получилось отметить принятым.",
		success: "принято.",
		call: func(ctx context.Context, px *praxisClient, id string) error {
			_, err := px.Acknowledge(ctx, id)
			return err
		},
	},
	praxisItemAction{
		verbs:   []string{"resolve_item", "сделано", "готово", "решено"},
		ask:     "какой пункт отметить сделанным?",
		op:      "resolve",
		failure: "не получилось отметить сделанным.",
		success: "отмечено как сделано.",
		call: func(ctx context.Context, px *praxisClient, id string) error {
			_, err := px.Resolve(ctx, id)
			return err
		},
	},
	praxisItemAction{
		verbs:   []string{"ignore_item", "игнорировать", "неважно"},
		ask:     "какой пункт игнорировать?",
		op:      "ignore",
		failure: "не получилось проигнорировать.",
		success: "проигнорировано.",
		call: func(ctx context.Context, px *praxisClient, id string) error {
			_, err := px.Ignore(ctx, id)
			return err
		},
	},
	praxisItemAction{
		verbs:   []string{"pin_item", "закрепить"},
		ask:     "какой пункт закрепить?",
		op:      "pin",
		failure: "не получилось закрепить.",
		success: "закреплено.",
		call: func(ctx context.Context, px *praxisClient, id string) error {
			_, err := px.Pin(ctx, id, true)
			return err
		},
	},
	listChangesCapability{},
}

// handlePraxisAct — dispatches ecosystem tool acts through the Praxis tools API.
// Returns "" when the act is not a Praxis verb (the caller falls through to the
// system command executor). Returns a reply string otherwise.
func (h *reactiveHandler) handlePraxisAct(ctx context.Context, dec router.Decision) string {
	if h.ecosystem == nil || h.ecosystem.praxis == nil {
		return ""
	}
	px := h.ecosystem.praxis
	for _, capability := range praxisCapabilities {
		for _, alias := range capability.aliases() {
			if alias == dec.Slots.Fn {
				return capability.handle(ctx, h, px, dec)
			}
		}
	}
	// Not a Praxis verb — let the caller fall through.
	return ""
}

// praxisItemAction is the shared shape of the item-lifecycle capabilities: take
// an item id from the value slot, call one Praxis endpoint, trace the result.
type praxisItemAction struct {
	verbs   []string
	ask     string // reply when no item id was given
	op      string // trace + log name of the operation
	failure string // reply when the Praxis call errors
	success string
	call    func(ctx context.Context, px *praxisClient, id string) error
}

func (a praxisItemAction) aliases() []string { return a.verbs }

func (a praxisItemAction) handle(ctx context.Context, h *reactiveHandler, px *praxisClient, dec router.Decision) string {
	id := dec.Slots.Value
	if id == "" {
		return a.ask
	}
	if err := a.call(ctx, px, id); err != nil {
		log.Printf("ecosystem: praxis %s %s: %v", a.op, id, err)
		return a.failure
	}
	h.recordPraxisTrace(ctx, a.op, map[string]any{"item_id": id})
	return a.success
}

// listAttentionCapability reads the attention digest and surfaces every item it speaks.
type listAttentionCapability struct{}

func (listAttentionCapability) aliases() []string {
	return []string{"list_attention", "attention", "внимание", "что требует внимания", "что нового"}
}

func (listAttentionCapability) handle(ctx context.Context, h *reactiveHandler, px *praxisClient, _ router.Decision) string {
	items, err := px.ListAttention(ctx, 20)
	if err != nil {
		log.Printf("ecosystem: praxis attention: %v", err)
		return "не могу сейчас узнать, что требует внимания."
	}
	if len(items) == 0 {
		return "ничего не требует внимания."
	}
	h.recordPraxisTrace(ctx, "list_attention", map[string]any{"count": len(items)})
	var parts []string
	for _, item := range items {
		title, _ := item["title"].(string)
		// importance arrives as JSON number ⇒ float64 over the HTTP contract.
		importance, _ := item["importance"].(float64)
		rule, _ := item["rule"].(string)
		s := title
		if importance > 0 {
			s += fmt.Sprintf(" (важность %d", int(importance))
			if rule != "" {
				s += ": " + rule
			}
			s += ")"
		}
		parts = append(parts, s)

		// Speaking an item surfaces it, it does not acknowledge it
		// (ECOSYSTEM-SPEC.md §2.3: surfaced != acknowledged). Best-effort:
		// a failed surface call must not block delivering the digest.
		if id, ok := item["id"].(string); ok && id != "" {
			if _, err := px.Surface(ctx, id); err != nil {
				log.Printf("ecosystem: praxis surface %s: %v", id, err)
			}
		}
	}
	return "требует внимания: " + strings.Join(parts, "; ")
}

// listChangesCapability reads the recent-changes feed.
type listChangesCapability struct{}

func (listChangesCapability) aliases() []string {
	return []string{"list_changes", "changes", "изменения", "что изменилось"}
}

func (listChangesCapability) handle(ctx context.Context, h *reactiveHandler, px *praxisClient, _ router.Decision) string {
	changes, err := px.ListChanges(ctx, 20)
	if err != nil {
		log.Printf("ecosystem: praxis changes: %v", err)
		return "не могу сейчас узнать об изменениях."
	}
	if len(changes) == 0 {
		return "нет изменений."
	}
	h.recordPraxisTrace(ctx, "list_changes", map[string]any{"count": len(changes)})
	var parts []string
	for _, c := range changes {
		title, _ := c["title"].(string)
		typ, _ := c["change_type"].(string)
		parts = append(parts, fmt.Sprintf("%s (%s)", title, typ))
	}
	return "изменения: " + strings.Join(parts, "; ")
}

// recordPraxisTrace — writes a fact recording a cross-service ecosystem call.
// The fact is stored with source "praxis:trace" so the proactive loop can
// reference it and the dashboard can display recent ecosystem activity.
func (h *reactiveHandler) recordPraxisTrace(ctx context.Context, operation string, details map[string]any) {
	now := h.now()
	value := operation
	if len(details) > 0 {
		if b, err := json.Marshal(details); err == nil {
			value = operation + " " + string(b)
		}
	}
	_, _ = h.api.WriteFact(ctx, ipc.WriteFactReq{
		Ts:         now,
		Kind:       "system",
		Key:        "praxis:" + operation,
		Value:      value,
		Source:     "praxis:trace",
		Confidence: 1.0,
	})
}

// handleHexisAct — resolves entity references through Nexus and executes
// matching capabilities through Hexis. Returns a reply string when handled,
// or "" to fall through to the system command executor.
func (h *reactiveHandler) handleHexisAct(ctx context.Context, dec router.Decision) string {
	if h.ecosystem == nil {
		return ""
	}

	// Resolve the utterance text as an entity reference through Nexus. An
	// ambiguous match must stop and clarify — never guess a mutation target.
	entityID, displayName, ambiguous, err := h.ecosystem.resolveEntityReference(ctx, dec.Slots.Text, nil)
	if err != nil {
		// A genuine Nexus dependency failure, not "no such entity" — stop here
		// and report degradation rather than silently falling through to the
		// local command executor (ECOSYSTEM-SPEC.md: services degrade
		// independently, never a silent all-clear).
		return "экосистема недоступна, попробуй ещё раз."
	}
	if len(ambiguous) > 0 {
		return "уточни, что именно: " + strings.Join(ambiguous, ", ") + "?"
	}
	if entityID == "" {
		return ""
	}

	// Discover Hexis capabilities for this entity. A resolved entity with a
	// genuine Hexis failure must not be treated as "no capabilities" and
	// fall through to unrelated local execution.
	caps, err := h.ecosystem.discoverCapabilities(ctx, entityID)
	if err != nil {
		return "экосистема недоступна, попробуй ещё раз."
	}
	if len(caps) == 0 {
		return ""
	}

	// Match the user's verb to a capability by name/description. Collect all
	// matches: more than one is itself ambiguous, so we ask rather than pick
	// the first (ecosystem invariant: no arbitrary target for mutation).
	verb := dec.Slots.Fn
	if verb == "" {
		verb = dec.Slots.Text
	}
	verbLower := strings.ToLower(verb)

	var matches []*hexisclient.Capability
	for i, c := range caps {
		if strings.Contains(strings.ToLower(c.Name), verbLower) ||
			(c.Description != "" && strings.Contains(strings.ToLower(c.Description), verbLower)) {
			matches = append(matches, &caps[i])
		}
	}
	if len(matches) == 0 {
		return ""
	}
	if len(matches) > 1 {
		var names []string
		for _, m := range matches {
			names = append(names, m.Name)
		}
		return "какую команду для " + displayName + ": " + strings.Join(names, ", ") + "?"
	}
	matched := matches[0]

	// Read-only capabilities run immediately; mutating ones are parked for an
	// explicit spoken confirm bound to this capability + target.
	if !matched.ReadOnly {
		h.mu.Lock()
		h.pendingHexis = &pendingHexisExec{
			capabilityID: matched.ID,
			capName:      matched.Name,
			entityID:     entityID,
			displayName:  displayName,
			expiry:       h.now().Add(confirmTTL),
		}
		h.mu.Unlock()
		return "выполнить «" + matched.Name + "» для " + displayName + "? скажи «да» или «нет»."
	}

	return h.execHexis(ctx, matched.ID, matched.Name, entityID, displayName)
}

// execHexis runs a resolved capability and records a cross-service trace with
// the correlation ID. It reports command success, never operational recovery
// (Praxis observes recovery independently).
func (h *reactiveHandler) execHexis(ctx context.Context, capID, capName, entityID, displayName string) string {
	correlationID, err := h.ecosystem.executeCapability(ctx, capID, entityID, nil)
	if err != nil {
		log.Printf("ecosystem: hexis execute error (cor=%s): %v", correlationID, err)
		return "не получилось выполнить команду для " + displayName + "."
	}
	h.recordPraxisTrace(ctx, "hexis:"+capName, map[string]any{
		"entity_id":      entityID,
		"entity_name":    displayName,
		"capability":     capName,
		"correlation_id": correlationID,
	})
	return "команда выполнена для " + displayName + "."
}