package state

import (
	"context"
	"time"

	"github.com/kamadopool/kamado-api/internal/logmon"
	"github.com/kamadopool/kamado-api/internal/store"
)

// BlockRecord is a found block, merged from a logmon event with bitcoind
// data if available. Hash and Reward are populated best-effort via the
// RPC lookup scheduled right after the log line is seen.
type BlockRecord struct {
	Height   int64     `json:"height"`
	Hash     string    `json:"hash,omitempty"`
	RewardBT float64   `json:"reward_btc,omitempty"`
	FoundAt  time.Time `json:"found_at"`
	Source   string    `json:"source"` // "logmon" for now; "zmq" later
}

// IngestBlockEvents reads block events from the tailer and appends them
// to the snapshot's block history. Runs until ctx is cancelled.
func (a *Aggregator) IngestBlockEvents(ctx context.Context, events <-chan logmon.BlockEvent) {
	for {
		select {
		case <-ctx.Done():
			return
		case ev, ok := <-events:
			if !ok {
				return
			}
			rec := BlockRecord{
				Height:  ev.Height,
				FoundAt: ev.SeenAt,
				Source:  "logmon",
			}
			// Best-effort enrich with hash via bitcoind.
			if a.RPC != nil {
				lookupCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
				if hash, err := a.RPC.GetBlockHash(lookupCtx, ev.Height); err == nil {
					rec.Hash = hash
				} else {
					a.Log.Warn("bitcoind getblockhash failed", "height", ev.Height, "err", err)
				}
				cancel()
			}
			if a.Store != nil {
				if err := a.Store.InsertBlock(store.Block{
					Height:   rec.Height,
					Hash:     rec.Hash,
					RewardBT: rec.RewardBT,
					FoundAt:  rec.FoundAt,
					Source:   rec.Source,
				}); err != nil {
					a.Log.Warn("block persist failed", "height", rec.Height, "err", err)
				}
			}
			pushed := a.appendBlock(rec)
			a.Log.Info("block recorded", "height", rec.Height, "hash", rec.Hash)
			// Push immediately so WebSocket clients see the solve
			// without waiting for the next poll tick.
			if a.OnRefresh != nil {
				a.OnRefresh(pushed)
			}
		}
	}
}

// maxBlockHistory caps in-memory block history. Persistence comes in
// Phase 2b.5 via SQLite; for now recent blocks survive only this
// process's lifetime.
const maxBlockHistory = 256

// appendBlock records a new block and returns a copy of the current
// snapshot with the updated history attached, suitable for an immediate
// WebSocket broadcast.
func (a *Aggregator) appendBlock(rec BlockRecord) Snapshot {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.blocks = append(a.blocks, rec)
	if len(a.blocks) > maxBlockHistory {
		a.blocks = a.blocks[len(a.blocks)-maxBlockHistory:]
	}
	snap := a.snap
	snap.RecentBlocks = make([]BlockRecord, len(a.blocks))
	copy(snap.RecentBlocks, a.blocks)
	a.snap = snap
	return snap
}

// loadPersistedBlocks seeds a.blocks from the store so history survives
// restarts. Safe to call with a nil Store — becomes a no-op.
func (a *Aggregator) loadPersistedBlocks() {
	if a.Store == nil {
		return
	}
	rows, err := a.Store.Recent(maxBlockHistory)
	if err != nil {
		a.Log.Warn("block history load failed", "err", err)
		return
	}
	// Store returns newest-first; a.blocks is newest-last.
	recs := make([]BlockRecord, 0, len(rows))
	for i := len(rows) - 1; i >= 0; i-- {
		r := rows[i]
		recs = append(recs, BlockRecord{
			Height:   r.Height,
			Hash:     r.Hash,
			RewardBT: r.RewardBT,
			FoundAt:  r.FoundAt,
			Source:   r.Source,
		})
	}
	a.mu.Lock()
	a.blocks = recs
	a.mu.Unlock()
	a.Log.Info("block history loaded", "count", len(recs))
}

// Blocks returns a copy of the recent block history, newest last.
func (a *Aggregator) Blocks() []BlockRecord {
	a.mu.RLock()
	defer a.mu.RUnlock()
	out := make([]BlockRecord, len(a.blocks))
	copy(out, a.blocks)
	return out
}