package main

import (
	"context"
	"errors"
	"log"

	"github.com/kami/maven/internal/mcp"
	"github.com/kami/maven/internal/phraser"
	"github.com/kami/maven/internal/router"
	"github.com/kami/maven/internal/tool"
)

// actionAct handles router.IntentAct: resolve the action, offer it to the
// ecosystems first, and run it behind the confirm gate and the allowlist.
// proposeGap and the confirm gate itself live in confirm.go.
//
// Action resolution happens in resolveAction (actionresolve.go) — a single
// boundary that produces an ActionCandidate before execution. This function
// consumes the candidate; it no longer decides which function/tool the user
// meant.
func (h *reactiveHandler) actionAct(ctx context.Context, dec router.Decision) string {
	// An allowlist or a model route is evidence about WHAT could run, never
	// authority to run it. Keep the user's negative command at the execution
	// boundary too: actionAct is also reached by rebuilt decisions outside the
	// ordinary pre-route ladder.
	if refusesCommand(dec) {
		return commandProhibitionReply
	}

	// Resolve the action: produce an ActionCandidate from the routing
	// decision. The candidate carries the resolved function, its arguments,
	// and where the resolution came from (route or matcher).
	candidate := h.resolveAction(ctx, dec)

	// Structural validation: is this candidate complete enough to proceed?
	// Unresolved (Fn empty) flows to proposeGap; invalid (Fn present but
	// malformed) is refused; valid proceeds to execution.
	validation := router.ValidateActionCandidate(candidate)
	noteActionValidation(ctx, validation)

	if !validation.Unresolved() && !validation.Valid() {
		// Resolved but structurally malformed: refuse execution.
		return phraser.A(phraser.ActFail, nil)
	}

	// The board is Maven's own store, so a spoken status change is answered here
	// and never offered to an ecosystem client (Vikunja #512). First, because
	// task_status is on no allowlist and no capability registry: reaching either
	// of them would answer a turn about his own task list with a gap.
	if candidate.Fn == router.TaskStatusFn {
		return h.resolveTaskStatus(ctx, dec, candidate)
	}

	// Praxis ecosystem tools: intercept before the system command executor.
	if h.ecosystem != nil && h.ecosystem.praxis != nil && candidate.ActionResolved() {
		if reply := h.handlePraxisAct(ctx, dec, candidate); reply != "" {
			return reply
		}
	}

	// Hexis ecosystem action: if ecosystem is configured and we have a verb
	// + entity text, try to resolve the entity and execute via Hexis.
	if h.ecosystem != nil && h.ecosystem.hexis != nil && router.ActHasEntityTarget(dec) {
		if reply := h.handleHexisAct(ctx, dec, candidate); reply != "" {
			return reply
		}
	}

	// Unresolved candidate ⇒ no allowlist match: scaffold a 'proposed' tool
	// the user can enable on the authed surface ("earn the right to ask").
	if !candidate.ActionResolved() {
		return h.proposeGap(ctx, dec)
	}
	out, err := h.tools.Exec(ctx, candidate.Fn, candidate.Args, false)
	if err != nil {
		switch {
		case errors.Is(err, tool.ErrNeedsConfirm):
			// destructive: park it and ask. The next utterance answers.
			phrase := actPhrase(candidate.Fn, candidate.Args)
			h.park(candidate.Fn, candidate.Args, phrase)
			return phraser.A(phraser.ActConfirm, map[string]string{"name": phrase})
		case errors.Is(err, tool.ErrUnknownTarget):
			// The verb reached a tool and the tail did not reach a target, so
			// nothing ran. Saying which word she could not place is the whole
			// answer: he either renames it or gives the row an alias that
			// carries the target, and both are one turn away (V-634).
			word := ""
			var unknown *tool.UnknownTargetError
			if errors.As(err, &unknown) {
				word = unknown.Target
			}
			return phraser.A(phraser.ActUnknownTarget, map[string]string{"name": word})
		case errors.Is(err, tool.ErrNeedsAuthedSurface):
			// Irreversible (internal/tool/risk.go). A confirm turn would not
			// help: everything that proposed this act — the STT, the router,
			// the fuzzy allowlist match — is a guess, and a spoken "да" checks
			// none of it. She names the gap instead.
			return phraser.A(phraser.ActNeedsAuthedSurface, nil)
		case errors.Is(err, tool.ErrNotEnabled):
			return h.proposeGap(ctx, dec)
		case errors.Is(err, tool.ErrNotConnected), errors.Is(err, mcp.ErrNotConnected), errors.Is(err, mcp.ErrNoServer):
			// The row is enabled and the backend is gone. Drafting a proposal
			// for it (the ErrNotEnabled path) would be answering the wrong
			// question.
			return phraser.A(phraser.ActServerDown, nil)
		case errors.Is(err, mcp.ErrToolGone):
			return phraser.A(phraser.ActWithdrawn, nil)
		case errors.Is(err, mcp.ErrNeedsArgs):
			// An MCP tool that wants named arguments a spoken verb cannot
			// supply. Guessing them would be a wrong act, so she says so
			// instead — the tool is still runnable from the authed surface,
			// where a human types them.
			return phraser.A(phraser.ActNeedsArgs, nil)
		}
		log.Printf("voice: tool %s: %v", candidate.Fn, err)
		if out != "" {
			return phraser.A(phraser.ActFailOut, map[string]string{"out": firstLine(out)})
		}
		return phraser.A(phraser.ActFail, nil)
	}
	if out != "" {
		return phraser.A(phraser.ActDoneOut, map[string]string{"out": firstLine(out)})
	}
	return phraser.A(phraser.ActDone, nil)
}