package main

import (
	"context"
	_ "embed"
	"errors"
	"fmt"
	"log"
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/kami/maven/internal/ipc"
	"github.com/kami/maven/internal/pattern"
	"github.com/kami/maven/internal/webauthn"
)

//go:embed routines.html
var routinesHTML string

// routinesTmpl — the proposed-routine review surface. One row per thing maven
// noticed, in her words, with at most two actions: accept or dismiss.
var routinesTmpl = parsePage("routines", routinesHTML, nil)

// routineView is one line on the page: what maven noticed, in her words, and
// how long ago she noticed it. A view model, not a database row — the template
// never formats an interval or a timestamp itself.
type routineView struct {
	ID      int64
	Phrase  string
	Noticed string
}

// handleRoutines serves the routine review surface (GET) and answers a
// proposal (POST id + action=accept|dismiss).
//
// Accept is gated at step-up, the same tier as enabling a tool: saying yes
// hands the trigger loop a new standing reason to speak to the human, so it
// moves the boundary and only an authed surface may do it. Dismiss is not
// gated — it only ever removes a reason to speak, so the worst a weaker caller
// can do is make maven quieter.
func handleRoutines(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI, session *webauthn.PasskeySession, requireStepUp bool) {
	if !requireCore(w, core, "routines") {
		return
	}
	ctx := r.Context()
	var msg string
	if r.Method == http.MethodPost {
		var ok bool
		if msg, ok = applyRoutinePost(w, r, core, session, requireStepUp); !ok {
			return
		}
	}
	proposed, err := core.ListProposedRoutines(ctx)
	if err != nil {
		log.Printf("routines: list: %v", err)
		http.Error(w, "routines error: "+err.Error(), http.StatusBadGateway)
		return
	}
	renderPage(w, routinesTmpl, struct {
		Msg      string
		Proposed []routineView
	}{msg, toRoutineViews(proposed)})
}

// applyRoutinePost performs one write and returns the message to show. Unlike
// the task form, a bad request here is an HTTP status rather than an inline
// note, so the second return says whether the response was already written.
func applyRoutinePost(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI, session *webauthn.PasskeySession, requireStepUp bool) (string, bool) {
	ctx := r.Context()
	action := r.FormValue("action")
	// "seed" is the one action with no routine to act on — it is what
	// MAKES a routine (Vikunja #518), so it runs before the id parse. It
	// lives on this route rather than a page of its own because it is
	// already the step-up-gated surface for this table, and a second gated
	// surface is a second thing to get wrong.
	if action == "seed" {
		if !stepUpGate(w, session, requireStepUp) {
			return "", false
		}
		out, err := seedRoutineEvent(ctx, core, r)
		if err != nil {
			log.Printf("routines: seed: %v", err)
			http.Error(w, "seed failed: "+err.Error(), http.StatusBadGateway)
			return "", false
		}
		return out, true
	}

	idStr := r.FormValue("id")
	var rid int64
	if n, _ := fmt.Sscanf(idStr, "%d", &rid); n != 1 {
		http.Error(w, "invalid id", http.StatusBadRequest)
		return "", false
	}
	switch action {
	case "accept":
		if !stepUpGate(w, session, requireStepUp) {
			return "", false
		}
		if err := acceptRoutine(ctx, core, rid); err != nil {
			log.Printf("routines: accept %d: %v", rid, err)
			http.Error(w, "accept failed: "+err.Error(), http.StatusBadGateway)
			return "", false
		}
		return "accepted routine — maven will remind you", true
	case "dismiss":
		if err := core.DismissProposedRoutine(ctx, rid); err != nil {
			log.Printf("routines: dismiss %d: %v", rid, err)
			http.Error(w, "dismiss failed: "+err.Error(), http.StatusBadGateway)
			return "", false
		}
		return "dismissed routine", true
	default:
		http.Error(w, "unknown action", http.StatusBadRequest)
		return "", false
	}
}

// toRoutineViews turns the wire rows into view models. The phrase comes from
// pattern.PhraseRoutine so the page says the same thing maven's voice says.
func toRoutineViews(rs []ipc.ProposedRoutine) []routineView {
	out := make([]routineView, 0, len(rs))
	for _, r := range rs {
		p := pattern.ProposedRoutine{Action: r.Action, Object: r.Object, IntervalDays: r.IntervalDays}
		noticed := "just now"
		if r.CreatedTs > 0 {
			noticed = time.Since(time.UnixMilli(r.CreatedTs)).Round(time.Minute).String() + " ago"
		}
		out = append(out, routineView{ID: r.ID, Phrase: pattern.PhraseRoutine(&p), Noticed: noticed})
	}
	return out
}

// acceptRoutine marks a proposal accepted. This page is the ONLY surface that
// may do it (Vikunja #367): accepting gives the tick loop a standing new
// reason to speak, which DESIGN.md puts at layer 3, and the button here is
// behind step-up. Voice can park the question and dismiss, never accept.
func acceptRoutine(ctx context.Context, core ipc.CoreAPI, id int64) error {
	proposed, err := core.ListProposedRoutines(ctx)
	if err != nil {
		return err
	}
	var found *ipc.ProposedRoutine
	for i := range proposed {
		if proposed[i].ID == id {
			found = &proposed[i]
			break
		}
	}
	if found == nil {
		return errors.New("no such proposed routine")
	}

	// No reminder is created here. Accepting only flips the status; the tick
	// loop reads accepted routines and nudges on the interval (Vikunja #366).
	// The old code made a one-shot reminder, so a non-weekly routine fired
	// once and then went quiet forever.
	return core.AcceptProposedRoutine(ctx, id)
}

// seedRoutineEvent drives one backdated fact write through core (Vikunja #518),
// so the pattern detector can be exercised against a running daemon instead of
// over real days. Refused unless mavend was started with -allow-seed; on an
// ordinary box the error says so and nothing is written.
//
// Takes "ago" rather than an absolute timestamp — hours before now, as a float
// so a QA sitting can space four seeds three hours apart without doing clock
// arithmetic. The detector's floor is two hours, and "0" is a legal answer
// meaning now.
func seedRoutineEvent(ctx context.Context, core ipc.CoreAPI, r *http.Request) (string, error) {
	key := strings.TrimSpace(r.FormValue("key"))
	value := strings.TrimSpace(r.FormValue("value"))
	if key == "" || value == "" {
		return "", errors.New("seed needs a key and a value")
	}
	agoHours, err := strconv.ParseFloat(strings.TrimSpace(r.FormValue("ago")), 64)
	if err != nil {
		return "", fmt.Errorf("seed: bad ago (hours before now): %w", err)
	}
	if agoHours < 0 {
		return "", errors.New("seed: ago is hours BEFORE now, so it cannot be negative")
	}
	resp, err := core.SeedEvent(ctx, ipc.SeedEventReq{
		Key:   key,
		Value: value,
		Ts:    time.Now().Add(-time.Duration(agoHours * float64(time.Hour))),
	})
	if err != nil {
		return "", err
	}
	if !resp.Extracted {
		return fmt.Sprintf("wrote fact %d, but %q is not in the action lexicon — no event, no pattern", resp.FactID, value), nil
	}
	if !resp.Proposed {
		return fmt.Sprintf("seeded %s/%s (fact %d, event %d) — not enough yet to propose", resp.Action, resp.Object, resp.FactID, resp.EventID), nil
	}
	return fmt.Sprintf("seeded %s/%s and PROPOSED routine %d, every %.1f days", resp.Action, resp.Object, resp.RoutineID, resp.IntervalDays), nil
}