package web

import (
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"strconv"
	"strings"
	"time"

	"pete/internal/storage"
)

// The expedition liveblog.
//
// Until now Pete only ever heard how a run *ended*: a zone cleared, a retreat, a
// death. The run itself — the fight that nearly went wrong two rooms back, the
// trap, the haul — was narrated into one Matrix DM and thrown away. The map on
// the adventurer page has always shown *where* somebody is. This shows what
// happened there, which is the half that makes it a story instead of a position.
//
// It arrives on its own channel, deliberately not the dispatch queue: beats are
// high-volume and low-stakes, and a chatty run must never be able to spend the
// retry budget a death dispatch depends on. They are also the one thing gogobee
// pushes that is history rather than state, so they append instead of replacing.
//
// The log is a *log*. Lines are short, factual and stacked; Pete does not
// narrate them. His voice is for the dispatch that gets filed when the run ends
// — a running commentary in the same register would drown it out.

const (
	// runBeatsMaxBatch bounds one push. gogobee batches on its 2-minute roster
	// tick and caps itself well below this; the limit is here to stop a
	// malformed or hostile payload spooling unbounded rows.
	runBeatsMaxBatch = 1000

	// runLogCap is how many beats the page shows. Read from the END — a log is
	// read for what just happened, and a party deep into its third region would
	// otherwise be showing its first morning forever.
	runLogCap = 60

	// runFinishedGrace is how long a finished run stays on the adventurer page.
	// The interesting moment is the one right after it ends ("what happened?"),
	// and that question is asked in minutes, not days. After this the page goes
	// back to being a sheet.
	runFinishedGrace = 6 * time.Hour

	// runRetentionDays is how long a finished run's beats are kept at all.
	runRetentionDays = 14
)

// runBeatsPush is the payload gogobee POSTs to /api/ingest/run.
type runBeatsPush struct {
	Beats []storage.RunBeat `json:"beats"`
}

// runLogLine is one beat rendered for the column.
type runLogLine struct {
	Emoji string
	Text  string
	Room  string // "4/9", or empty for a beat that isn't in a room
	When  string
	Hurt  bool // the party took damage or lost: worth an eye
	Good  bool // a find, a kill, a clear
}

// RunLogView is the liveblog as the page draws it.
type RunLogView struct {
	Has     bool
	Live    bool
	Zone    string
	Outcome string // "" while live
	Lines   []runLogLine
	Rooms   string // "4 / 9"
}

// handleRunIngest stores a batch of beats.
//
// Note what is NOT rejected here: an unknown beat kind. That is the same lesson
// the dispatch ingest learned the hard way — a beat Pete has no line for is a
// styling problem, not a validity problem, and 400ing it would silently delete a
// game event and park the row upstream forever. An unknown kind is stored, and
// renders as its own bare noun rather than not at all.
func (s *Server) handleRunIngest(w http.ResponseWriter, r *http.Request) {
	if !s.adv.Enabled {
		http.NotFound(w, r)
		return
	}
	if !s.bearerOK(r) {
		http.Error(w, "unauthorized", http.StatusUnauthorized)
		return
	}

	var push runBeatsPush
	if err := json.NewDecoder(io.LimitReader(r.Body, 4<<20)).Decode(&push); err != nil {
		http.Error(w, "bad json", http.StatusBadRequest)
		return
	}
	if len(push.Beats) > runBeatsMaxBatch {
		http.Error(w, "batch too large", http.StatusBadRequest)
		return
	}

	now := time.Now().Unix()
	kept := make([]storage.RunBeat, 0, len(push.Beats))
	for i, b := range push.Beats {
		// run_id and seq ARE the row. Without both there is nothing to be
		// idempotent on, and a re-send would duplicate the story.
		if b.RunID == "" || b.Seq <= 0 {
			http.Error(w, fmt.Sprintf("beat %d: run_id and a positive seq are required", i), http.StatusBadRequest)
			return
		}
		// A beat with no clock can't be ordered against the rest of the run and
		// would break the retention sweep, which keys on when a run ended.
		if b.OccurredAt <= 0 {
			b.OccurredAt = now
		}
		kept = append(kept, b)
	}
	if len(kept) == 0 {
		w.WriteHeader(http.StatusOK)
		return
	}

	if err := storage.AppendRunBeats(kept); err != nil {
		slog.Error("run ingest: append failed", "err", err, "beats", len(kept))
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}
	slog.Debug("run ingest: beats stored", "beats", len(kept))
	w.WriteHeader(http.StatusOK)
}

// runLogFor builds the liveblog for one adventurer, or an empty view when there
// is nothing worth showing.
func runLogFor(token string) RunLogView {
	run, ok, err := storage.LatestRunForToken(token)
	if err != nil {
		slog.Error("run log: header lookup failed", "err", err)
		return RunLogView{}
	}
	if !ok {
		return RunLogView{}
	}
	// A run that finished days ago is not news. It stays in the database — the
	// dispatch that announced it links to it — but the adventurer page is about
	// now, and an old log sitting under a live map reads as the live one.
	if !run.Live() && time.Since(time.Unix(run.EndedAt, 0)) > runFinishedGrace {
		return RunLogView{}
	}

	beats, err := storage.RunBeats(run.RunID, runLogCap)
	if err != nil {
		slog.Error("run log: beats lookup failed", "run", run.RunID, "err", err)
		return RunLogView{}
	}
	if len(beats) == 0 {
		return RunLogView{}
	}

	v := RunLogView{
		Has:     true,
		Live:    run.Live(),
		Zone:    run.Zone,
		Outcome: run.Outcome,
	}
	if run.TotalRooms > 0 {
		last := beats[len(beats)-1]
		if last.Room > 0 {
			v.Rooms = fmt.Sprintf("%d / %d", last.Room, run.TotalRooms)
		}
	}
	for _, b := range beats {
		// The zone lives on the header, not on every beat — gogobee sends it once,
		// on `start`, and the beat table has no column for it. Handing it back here
		// is what stops the opening line reading "Set out into something", which is
		// what a straight render of the stored row produces.
		if b.Zone == "" {
			b.Zone = run.Zone
		}
		if line, ok := renderRunBeat(b); ok {
			v.Lines = append(v.Lines, line)
		}
	}
	return v
}

// renderRunBeat turns one beat into one line. ok is false for a beat with
// nothing to say — a haul of nothing, a room with no identity.
//
// Everything here is assembled from the beat's own nouns and numbers. gogobee
// sends no prose down this channel and Pete invents none: the point of the log
// is that it is what happened, in order, and a line that reads better than the
// facts support is a line that is lying about a run somebody actually walked.
func renderRunBeat(b storage.RunBeat) (runLogLine, bool) {
	l := runLogLine{When: time.Unix(b.OccurredAt, 0).UTC().Format("15:04")}
	if b.Room > 0 && b.TotalRooms > 0 {
		l.Room = fmt.Sprintf("%d/%d", b.Room, b.TotalRooms)
	}

	switch b.Kind {
	case "start":
		l.Emoji = "🚪"
		l.Text = "Set out into " + orUnknown(b.Zone)
		if b.TotalRooms > 0 {
			l.Text += fmt.Sprintf(" — %d rooms deep", b.TotalRooms)
		}

	case "room":
		l.Emoji = roomEmoji(b.RoomKind)
		what, named := roomWord(b.RoomKind)
		if b.Outcome == "doubled back" {
			// "Doubled back to the next room" is a contradiction — the room behind
			// you is the last one, not the next. Only a room with a name of its own
			// is worth pointing at on the way back.
			if !named {
				l.Text = "Doubled back a room"
				return l, true
			}
			l.Text = "Doubled back to the " + what
			return l, true
		}
		l.Text = "Into the " + what

	case "combat":
		switch b.Outcome {
		case "won":
			l.Emoji = "⚔️"
			l.Good = true
			l.Text = orUnknown(b.Target) + " down"
			if b.Amount > 0 {
				l.Text += fmt.Sprintf(" — took %d", b.Amount)
			} else {
				l.Text += " — untouched"
			}
		case "retreat":
			l.Emoji = "⏳"
			l.Hurt = true
			l.Text = "Outlasted by " + orUnknown(b.Target) + " — withdrew"
		default:
			l.Emoji = "💀"
			l.Hurt = true
			l.Text = "Fell to " + orUnknown(b.Target)
		}
		// The crown marks a boss BEATEN. On a boss that killed you it reads as
		// congratulating the wrong party, so a loss keeps its skull whatever room
		// it happened in.
		if b.RoomKind == "boss" && b.Outcome == "won" {
			l.Emoji = "👑"
		} else if b.RoomKind == "elite" && b.Outcome == "won" {
			l.Text = "Elite " + l.Text
		}
		if hp := hpTail(b); hp != "" {
			l.Text += hp
		}
		if b.Crits > 0 {
			l.Text += fmt.Sprintf(" · %s", plural(b.Crits, "critical hit", "critical hits"))
		}

	case "trap":
		l.Emoji = "🕳"
		if b.Amount <= 0 {
			l.Text = "Trap — stepped over it"
			l.Good = true
			break
		}
		l.Hurt = true
		l.Text = fmt.Sprintf("Trap sprung — %d damage", b.Amount)
		if hp := hpTail(b); hp != "" {
			l.Text += hp
		}

	case "treasure":
		l.Emoji = "💎"
		l.Good = true
		l.Text = "Found " + orUnknown(b.Target)
		switch b.Outcome {
		case "cache":
			l.Text += " in a cache"
		case "boss":
			l.Text += " on the boss"
		}

	case "haul":
		if b.Amount <= 0 {
			return runLogLine{}, false
		}
		l.Emoji = "🧺"
		l.Text = fmt.Sprintf("Gathered %d", b.Amount)
		if b.Target != "" {
			l.Text += " — mostly " + b.Target
		}
		if b.Count > 1 {
			l.Text += fmt.Sprintf(" (%d kinds)", b.Count)
		}

	case "lock":
		l.Emoji = "🔒"
		if b.Outcome == "picked" {
			l.Good = true
			l.Text = "Picked the lock"
			if b.Target != "" {
				l.Text += " — " + b.Target
			}
			break
		}
		l.Hurt = true
		l.Text = "Every way on sealed — doubled back"

	case "region":
		l.Emoji = "🗺"
		l.Room = "" // a border is between rooms, not in one
		l.Text = "Crossed into " + orUnknown(b.Target)
		if b.Region != "" {
			l.Text = "Left " + b.Region + " for " + orUnknown(b.Target)
		}

	case "end":
		switch b.Outcome {
		case "cleared":
			l.Emoji = "🏆"
			l.Good = true
			l.Text = "Run complete"
		case "died":
			l.Emoji = "💀"
			l.Hurt = true
			l.Text = "Run ended — didn't make it out"
		case "retreated":
			l.Emoji = "🚑"
			l.Hurt = true
			l.Text = "Withdrew, wounded but alive"
		default:
			l.Emoji = "🚪"
			l.Text = "Run ended"
		}

	default:
		// A kind Pete has no line for. Show the noun rather than nothing — the
		// same call the dispatch ingest makes for an unknown event type, and for
		// the same reason: silence here is indistinguishable from a bug.
		l.Emoji = "•"
		l.Text = strings.ReplaceAll(b.Kind, "_", " ")
		if b.Target != "" {
			l.Text += " — " + b.Target
		}
	}
	if l.Text == "" {
		return runLogLine{}, false
	}
	return l, true
}

// hpTail is the " (HP 21/34)" suffix, and only when the pair is real. A zero max
// means gogobee didn't send one, not that the adventurer has no health.
func hpTail(b storage.RunBeat) string {
	if b.HPMax <= 0 {
		return ""
	}
	return fmt.Sprintf(" · %d/%d HP", b.HP, b.HPMax)
}

// roomWord names a room the way somebody walking through it would. "exploration"
// is the engine's word for "a room", and echoing it back reads like a database
// column; the rooms with an actual identity get named and the rest are just the
// next one along.
// named is false for a room with no identity of its own, which is most of them.
// Callers that need to say something about a *particular* room have to know the
// difference — see the doubled-back branch.
func roomWord(kind string) (word string, named bool) {
	switch kind {
	case "entry":
		return "entrance", true
	case "trap":
		return "trapped room", true
	case "elite":
		return "elite's room", true
	case "boss":
		return "boss chamber", true
	case "secret":
		return "hidden room", true
	}
	return "next room", false
}

func roomEmoji(kind string) string {
	switch kind {
	case "trap":
		return "🕳"
	case "elite":
		return "🛡"
	case "boss":
		return "👑"
	case "entry":
		return "🚪"
	}
	return "🚶"
}

func orUnknown(s string) string {
	if s == "" {
		return "something"
	}
	return s
}

func plural(n int, one, many string) string {
	if n == 1 {
		return "1 " + one
	}
	return strconv.Itoa(n) + " " + many
}