package db

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/dtoro/oikos/internal/domain"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"gopkg.in/yaml.v3"
)

// SeedResult holds counts from a seed ingest operation.
type SeedResult struct {
	Lifecycles       int
	EntityTypes      int
	RelationshipTypes int
	Entities         int
	Relationships    int
	RiskClasses      int
	ApprovalRules    int
	AutonomySettings int
}

// IngestOntologySeed ingests seeds/ontology.yaml into the DB.
func IngestOntologySeed(ctx context.Context, tx pgx.Tx, data map[string]any) (*SeedResult, error) {
	r := &SeedResult{}

	// Lifecycles
	lifecycles, _ := data["lifecycles"].(map[string]any)
	for id, raw := range lifecycles {
		lcMap, _ := raw.(map[string]any)
		states := toStringSlice(lcMap["states"])
		defaultState, _ := lcMap["default_state"].(string)
		terminalStates := toStringSlice(lcMap["terminal_states"])
		if len(terminalStates) == 0 {
			terminalStates = []string{}
		}
		transitionsBytes, _ := json.Marshal(lcMap["transitions"])
		_, err := tx.Exec(ctx,
			`INSERT INTO lifecycle_defs (id, states, default_state, terminal_states, transitions)
			 VALUES ($1, $2, $3, $4, $5)
			 ON CONFLICT (id) DO UPDATE SET states = $2, default_state = $3,
			   terminal_states = $4, transitions = $5`,
			id, states, defaultState, terminalStates, string(transitionsBytes))
		if err != nil {
			return nil, fmt.Errorf("lifecycle %s: %w", id, err)
		}
		r.Lifecycles++
	}

	// Entity types — need to handle parent_type FK, so insert in dependency order
	// (types with no parent first, then their children)
	types, _ := data["entity_types"].(map[string]any)
	if err := insertEntityTypes(ctx, tx, types, r); err != nil {
		return nil, err
	}

	// Relationship types
	relTypes, _ := data["relationship_types"].(map[string]any)
	for name, raw := range relTypes {
		rtMap, _ := raw.(map[string]any)
		inverse, _ := rtMap["inverse"].(string)
		sourceType, _ := rtMap["source"].(string)
		targetType, _ := rtMap["target"].(string)
		cardinality, _ := rtMap["cardinality"].(string)
		desc, _ := rtMap["description"].(string)
		_, err := tx.Exec(ctx,
			`INSERT INTO relationship_types (name, inverse, source_type, target_type, cardinality, description)
			 VALUES ($1, $2, $3, $4, $5, $6)
			 ON CONFLICT (name) DO UPDATE SET inverse = $2, source_type = $3,
			   target_type = $4, cardinality = $5, description = $6`,
			name, nullableStr(inverse), sourceType, targetType, cardinality, desc)
		if err != nil {
			return nil, fmt.Errorf("relationship_type %s: %w", name, err)
		}
		r.RelationshipTypes++
	}

	return r, nil
}

// IngestInventorySeed ingests seeds/inventory.yaml into the DB.
func IngestInventorySeed(ctx context.Context, tx pgx.Tx, data map[string]any) (*SeedResult, error) {
	r := &SeedResult{}

	// Entities
	entities, _ := data["entities"].([]any)
	for _, raw := range entities {
		eMap, ok := raw.(map[string]any)
		if !ok {
			continue
		}
		slug, _ := eMap["slug"].(string)
		typeName, _ := eMap["type"].(string)
		name, _ := eMap["name"].(string)
		state, _ := eMap["state"].(string)
		attrs := eMap["attributes"]

		// Generate UUIDv7 for new entities, or find existing by slug
		entityID, err := getOrCreateEntityID(ctx, tx, slug)
		if err != nil {
			return nil, fmt.Errorf("entity %s: %w", slug, err)
		}

		attrsBytes, _ := json.Marshal(attrs)
		_, err = tx.Exec(ctx,
			`INSERT INTO entities (id, slug, type, name, state, attributes, version, created_at, updated_at)
			 VALUES ($1, $2, $3, $4, $5, $6, 1, now(), now())
			 ON CONFLICT (slug) DO UPDATE SET type = $3, name = $4, state = $5,
			   attributes = $6, updated_at = now()`,
			entityID, slug, typeName, name, nullableStr(state), string(attrsBytes))
		if err != nil {
			return nil, fmt.Errorf("entity %s: %w", slug, err)
		}
		r.Entities++
	}

	// Relationships
	rels, _ := data["relationships"].([]any)
	for _, raw := range rels {
		relMap, ok := raw.(map[string]any)
		if !ok {
			continue
		}
		source, _ := relMap["source"].(string)
		target, _ := relMap["target"].(string)
		relType, _ := relMap["type"].(string)
		attrs := relMap["attributes"]

		sourceID, err := getEntityIDBySlug(ctx, tx, source)
		if err != nil {
			return nil, fmt.Errorf("rel from %s: %w", source, err)
		}
		targetID, err := getEntityIDBySlug(ctx, tx, target)
		if err != nil {
			return nil, fmt.Errorf("rel to %s: %w", target, err)
		}

		attrsBytes, _ := json.Marshal(attrs)
		_, err = tx.Exec(ctx,
			`INSERT INTO relationships (source_id, target_id, type, attributes, valid_from, valid_to)
			 VALUES ($1, $2, $3, $4, now(), NULL)
			 ON CONFLICT (source_id, target_id, type, valid_from)
			 DO UPDATE SET attributes = $4`,
			sourceID, targetID, relType, string(attrsBytes))
		if err != nil {
			return nil, fmt.Errorf("rel %s→%s %s: %w", source, target, relType, err)
		}
		r.Relationships++
	}

	return r, nil
}

// IngestPolicySeed ingests seeds/policy.yaml into the DB.
func IngestPolicySeed(ctx context.Context, tx pgx.Tx, data map[string]any) (*SeedResult, error) {
	r := &SeedResult{}

	// Risk classes
	riskClasses, _ := data["risk_classes"].(map[string]any)
	for name, raw := range riskClasses {
		rcMap, _ := raw.(map[string]any)
		desc, _ := rcMap["description"].(string)
		approval, _ := rcMap["approval_required"].(string)
		autonomy, _ := rcMap["autonomy_allowed"].(bool)
		_, err := tx.Exec(ctx,
			`INSERT INTO risk_classes (name, description, approval_required, autonomy_allowed)
			 VALUES ($1, $2, $3, $4)
			 ON CONFLICT (name) DO UPDATE SET description = $2, approval_required = $3, autonomy_allowed = $4`,
			name, desc, approval, autonomy)
		if err != nil {
			return nil, fmt.Errorf("risk_class %s: %w", name, err)
		}
		r.RiskClasses++
	}

	// Approval rules
	rules, _ := data["approval_rules"].([]any)
	for _, raw := range rules {
		ruleMap, ok := raw.(map[string]any)
		if !ok {
			continue
		}
		entityType, _ := ruleMap["entity_type"].(string)
		action, _ := ruleMap["action"].(string)
		riskClass, _ := ruleMap["risk_class"].(string)
		autonomy, _ := ruleMap["autonomy_level"].(string)
		scopeEntity, _ := ruleMap["scope_entity"].(string)

		var scopeID any
		if scopeEntity != "" {
			id, err := getEntityIDBySlug(ctx, tx, scopeEntity)
			if err == nil {
				scopeID = id
			}
		}

		ruleID := uuid.New()
		_, err := tx.Exec(ctx,
			`INSERT INTO approval_rules (id, entity_type, action, risk_class, autonomy_level, scope_entity, version, updated_at)
			 VALUES ($1, $2, $3, $4, $5, $6, 1, now())
			 ON CONFLICT (entity_type, action, scope_entity)
			 DO UPDATE SET risk_class = $4, autonomy_level = $5, scope_entity = $6, updated_at = now()`,
			ruleID, nullableStr(entityType), action, riskClass, autonomy, scopeID)
		if err != nil {
			return nil, fmt.Errorf("approval_rule %s/%s: %w", entityType, action, err)
		}
		r.ApprovalRules++
	}

	// Autonomy settings
	settings, _ := data["autonomy_settings"].(map[string]any)
	for key, raw := range settings {
		val, _ := raw.(string)
		_, err := tx.Exec(ctx,
			`INSERT INTO autonomy_settings (key, value, version, updated_at)
			 VALUES ($1, $2, 1, now())
			 ON CONFLICT (key) DO UPDATE SET value = $2, updated_at = now()`,
			key, val)
		if err != nil {
			return nil, fmt.Errorf("autonomy_setting %s: %w", key, err)
		}
		r.AutonomySettings++
	}

	return r, nil
}

// --- Helpers ---

// getOrCreateEntityID returns the UUID for a slug, generating a new UUIDv7 if not found.
func getOrCreateEntityID(ctx context.Context, tx pgx.Tx, slug string) (uuid.UUID, error) {
	var id uuid.UUID
	err := tx.QueryRow(ctx, "SELECT id FROM entities WHERE slug = $1", slug).Scan(&id)
	if err == nil {
		return id, nil
	}
	// Generate a time-ordered UUID (using uuid.New for now; UUIDv7 in production)
	return uuid.New(), nil
}

// getEntityIDBySlug resolves a slug to its UUID.
func getEntityIDBySlug(ctx context.Context, tx pgx.Tx, slug string) (uuid.UUID, error) {
	var id uuid.UUID
	err := tx.QueryRow(ctx, "SELECT id FROM entities WHERE slug = $1", slug).Scan(&id)
	if err != nil {
		return uuid.Nil, fmt.Errorf("resolve slug %s: %w", slug, err)
	}
	return id, nil
}

// insertEntityTypes inserts entity types in dependency order (parents before children).
func insertEntityTypes(ctx context.Context, tx pgx.Tx, types map[string]any, r *SeedResult) error {
	// Build a dependency graph and insert in topological order
	// Simple approach: insert types with no parent first, then iterate
	inserted := make(map[string]bool)
	remaining := make(map[string]map[string]any)
	for name, raw := range types {
		tMap, _ := raw.(map[string]any)
		remaining[name] = tMap
	}

	maxPasses := 10
	for pass := 0; pass < maxPasses && len(remaining) > 0; pass++ {
		for name, tMap := range remaining {
			parent, _ := tMap["parent"].(string)
			if parent == "" || inserted[parent] {
				if err := insertOneEntityType(ctx, tx, name, tMap); err != nil {
					return err
				}
				inserted[name] = true
				delete(remaining, name)
				r.EntityTypes++
			}
		}
	}

	if len(remaining) > 0 {
		return fmt.Errorf("circular or missing parent in entity types: %v", keysOf(remaining))
	}
	return nil
}

func insertOneEntityType(ctx context.Context, tx pgx.Tx, name string, tMap map[string]any) error {
	parent, _ := tMap["parent"].(string)
	isAbstract, _ := tMap["abstract"].(bool)
	domain, _ := tMap["domain"].(string)
	layer, _ := tMap["layer"].(string)
	desc, _ := tMap["description"].(string)
	lifecycleID, _ := tMap["lifecycle"].(string)
	attrSchema := tMap["attribute_schema"]

	schemaBytes, _ := json.Marshal(attrSchema)
	_, err := tx.Exec(ctx,
		`INSERT INTO entity_types (name, parent_type, is_abstract, domain, layer, description,
		     lifecycle_id, attribute_schema, schema_version, status, created_at, updated_at)
		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, 1, 'active', now(), now())
		 ON CONFLICT (name) DO UPDATE SET parent_type = $2, is_abstract = $3, domain = $4,
		   layer = $5, description = $6, lifecycle_id = $7, attribute_schema = $8, updated_at = now()`,
		name, nullableStr(parent), isAbstract, domain, layer, desc, nullableStr(lifecycleID), nullableStr(string(schemaBytes)))
	return err
}

func toStringSlice(v any) []string {
	if v == nil {
		return nil
	}
	switch s := v.(type) {
	case []string:
		return s
	case []any:
		out := make([]string, 0, len(s))
		for _, item := range s {
			if str, ok := item.(string); ok {
				out = append(out, str)
			}
		}
		return out
	}
	return nil
}

func nullableStr(s string) any {
	if s == "" {
		return nil
	}
	return s
}

func keysOf(m map[string]map[string]any) []string {
	keys := make([]string, 0, len(m))
	for k := range m {
		keys = append(keys, k)
	}
	return keys
}

// ExportToYAML regenerates the three seed YAMLs from the DB (for DR / version control, D6).
func ExportToYAML(ctx context.Context, pool *Pool) (map[string][]byte, error) {
	result := make(map[string][]byte)

	// Export ontology
	onto, err := exportOntology(ctx, pool)
	if err != nil {
		return nil, fmt.Errorf("export ontology: %w", err)
	}
	result["ontology.yaml"], _ = yaml.Marshal(onto)

	// Export inventory
	inv, err := exportInventory(ctx, pool)
	if err != nil {
		return nil, fmt.Errorf("export inventory: %w", err)
	}
	result["inventory.yaml"], _ = yaml.Marshal(inv)

	// Export policy
	pol, err := exportPolicy(ctx, pool)
	if err != nil {
		return nil, fmt.Errorf("export policy: %w", err)
	}
	result["policy.yaml"], _ = yaml.Marshal(pol)

	return result, nil
}

func exportOntology(ctx context.Context, pool *Pool) (map[string]any, error) {
	// TODO: implement full export from DB
	return map[string]any{"version": 1}, nil
}

func exportInventory(ctx context.Context, pool *Pool) (map[string]any, error) {
	// TODO: implement full export from DB
	return map[string]any{"version": 1}, nil
}

func exportPolicy(ctx context.Context, pool *Pool) (map[string]any, error) {
	// TODO: implement full export from DB
	return map[string]any{"version": 1}, nil
}

// Unused import suppression for domain (will be needed when we add more logic)
var _ = domain.Entity{}
var _ = time.Now