package controlplane

import (
	"context"
	"crypto/rand"
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"net/url"
	"regexp"
	"strings"
	"time"

	"github.com/jackc/pgx/v5"
)

var (
	ErrNotFound       = errors.New("control-plane resource not found")
	slugPattern       = regexp.MustCompile(`^[a-z0-9][a-z0-9-]{1,62}[a-z0-9]$`)
	nonSlugCharacters = regexp.MustCompile(`[^a-z0-9]+`)
)

func (s *Store) CreateTenant(ctx context.Context, input CreateTenantInput) (Tenant, int64, error) {
	input.Slug = strings.ToLower(strings.TrimSpace(input.Slug))
	input.Name = strings.TrimSpace(input.Name)
	if !slugPattern.MatchString(input.Slug) || input.Name == "" {
		return Tenant{}, 0, errors.New("tenant requires a 3-64 character lowercase slug and a name")
	}
	tx, err := s.db.Begin(ctx)
	if err != nil {
		return Tenant{}, 0, err
	}
	defer tx.Rollback(ctx)
	var result Tenant
	err = tx.QueryRow(ctx, `
		INSERT INTO tenants (slug, name) VALUES ($1, $2)
		RETURNING id::text, slug, name, status, created_at`, input.Slug, input.Name,
	).Scan(&result.ID, &result.Slug, &result.Name, &result.Status, &result.CreatedAt)
	if err != nil {
		return Tenant{}, 0, fmt.Errorf("create tenant: %w", err)
	}
	generation, err := bumpGeneration(ctx, tx)
	if err != nil {
		return Tenant{}, 0, err
	}
	if err := tx.Commit(ctx); err != nil {
		return Tenant{}, 0, err
	}
	return result, generation, nil
}

func (s *Store) CreateProject(ctx context.Context, input CreateProjectInput) (Project, int64, error) {
	input.Slug = strings.ToLower(strings.TrimSpace(input.Slug))
	input.Name = strings.TrimSpace(input.Name)
	if input.TenantID == "" || !slugPattern.MatchString(input.Slug) || input.Name == "" {
		return Project{}, 0, errors.New("project requires tenant_id, a 3-64 character lowercase slug, and a name")
	}
	tx, err := s.db.Begin(ctx)
	if err != nil {
		return Project{}, 0, err
	}
	defer tx.Rollback(ctx)
	var result Project
	err = tx.QueryRow(ctx, `
		INSERT INTO projects (tenant_id, slug, name) VALUES ($1, $2, $3)
		RETURNING id::text, tenant_id::text, slug, name, status, created_at`, input.TenantID, input.Slug, input.Name,
	).Scan(&result.ID, &result.TenantID, &result.Slug, &result.Name, &result.Status, &result.CreatedAt)
	if err != nil {
		return Project{}, 0, fmt.Errorf("create project: %w", err)
	}
	generation, err := bumpGeneration(ctx, tx)
	if err != nil {
		return Project{}, 0, err
	}
	if err := tx.Commit(ctx); err != nil {
		return Project{}, 0, err
	}
	return result, generation, nil
}

func (s *Store) CreateAPIKey(ctx context.Context, input CreateAPIKeyInput) (CreatedAPIKey, int64, error) {
	input.Name = strings.TrimSpace(input.Name)
	if input.TenantID == "" || input.ProjectID == "" || input.Name == "" {
		return CreatedAPIKey{}, 0, errors.New("API key requires tenant_id, project_id, and name")
	}
	if len(input.Name) > 120 || input.MonthlySpendMicros < 0 {
		return CreatedAPIKey{}, 0, errors.New("API key name or monthly spend limit is invalid")
	}
	if input.ExpiresAt != nil && !input.ExpiresAt.After(time.Now()) {
		return CreatedAPIKey{}, 0, errors.New("API key expiry must be in the future")
	}
	if len(input.Scopes) == 0 {
		input.Scopes = []string{"inference"}
	}
	scopes := uniqueStrings(input.Scopes)
	tags := uniqueStrings(input.Tags)
	allowedModels := uniqueStrings(input.AllowedModels)
	if len(scopes) > 20 || len(tags) > 20 || len(allowedModels) > 200 {
		return CreatedAPIKey{}, 0, errors.New("API key has too many scopes, tags, or model restrictions")
	}
	for _, value := range append(append(append([]string{}, scopes...), tags...), allowedModels...) {
		if len(value) > 160 {
			return CreatedAPIKey{}, 0, errors.New("API key scope, tag, or model ID is too long")
		}
	}
	scopesJSON, _ := json.Marshal(scopes)
	tagsJSON, _ := json.Marshal(tags)
	random := make([]byte, 32)
	if _, err := rand.Read(random); err != nil {
		return CreatedAPIKey{}, 0, fmt.Errorf("generate API key: %w", err)
	}
	rawKey := "sk-aigw-" + base64.RawURLEncoding.EncodeToString(random)
	hash := sha256.Sum256([]byte(rawKey))
	prefix := rawKey[:min(18, len(rawKey))] + "..."

	tx, err := s.db.Begin(ctx)
	if err != nil {
		return CreatedAPIKey{}, 0, err
	}
	defer tx.Rollback(ctx)
	var result CreatedAPIKey
	err = tx.QueryRow(ctx, `
		INSERT INTO api_keys (tenant_id, project_id, name, key_prefix, key_hash, scopes, tags, monthly_spend_micros, expires_at)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
		RETURNING id::text, tenant_id::text, project_id::text, name, key_prefix, scopes, tags,
		          monthly_spend_micros, status, expires_at, last_used_at, created_at`,
		input.TenantID, input.ProjectID, input.Name, prefix, hash[:], scopesJSON, tagsJSON,
		input.MonthlySpendMicros, input.ExpiresAt,
	).Scan(&result.ID, &result.TenantID, &result.ProjectID, &result.Name, &result.KeyPrefix,
		&scopesJSON, &tagsJSON, &result.MonthlySpendMicros, &result.Status, &result.ExpiresAt,
		&result.LastUsedAt, &result.CreatedAt)
	if err != nil {
		return CreatedAPIKey{}, 0, fmt.Errorf("create API key: %w", err)
	}
	if len(allowedModels) > 0 {
		command, err := tx.Exec(ctx, `
			INSERT INTO api_key_model_restrictions (api_key_id, model_id)
			SELECT $1, id FROM models WHERE public_id = ANY($2::text[])`, result.ID, allowedModels)
		if err != nil {
			return CreatedAPIKey{}, 0, fmt.Errorf("restrict API key models: %w", err)
		}
		if command.RowsAffected() != int64(len(allowedModels)) {
			return CreatedAPIKey{}, 0, errors.New("one or more allowed model IDs do not exist")
		}
	}
	result.Scopes = scopes
	result.Tags = tags
	result.AllowedModels = allowedModels
	result.Key = rawKey
	generation, err := bumpGeneration(ctx, tx)
	if err != nil {
		return CreatedAPIKey{}, 0, err
	}
	if err := tx.Commit(ctx); err != nil {
		return CreatedAPIKey{}, 0, err
	}
	return result, generation, nil
}

func (s *Store) RevokeAPIKey(ctx context.Context, id string) (int64, error) {
	return s.toggle(ctx, `UPDATE api_keys SET status = 'revoked', revoked_at = now() WHERE id = $1 AND status <> 'revoked'`, id)
}

func (s *Store) CreateProvider(ctx context.Context, input CreateProviderInput) (Provider, int64, error) {
	input.Slug = strings.ToLower(strings.TrimSpace(input.Slug))
	input.Name = strings.TrimSpace(input.Name)
	if input.Slug == "" {
		input.Slug = strings.Trim(nonSlugCharacters.ReplaceAllString(strings.ToLower(input.Name), "-"), "-")
		if len(input.Slug) > 64 {
			input.Slug = strings.TrimRight(input.Slug[:64], "-")
		}
	}
	input.BaseURL = strings.TrimRight(strings.TrimSpace(input.BaseURL), "/")
	input.WireAPI = strings.TrimSpace(input.WireAPI)
	if input.WireAPI == "" {
		if input.Protocol == "anthropic" {
			input.WireAPI = "messages"
		} else {
			input.WireAPI = "chat_completions"
		}
	}
	if !slugPattern.MatchString(input.Slug) || input.Name == "" || input.APIKey == "" || (input.Protocol != "openai" && input.Protocol != "anthropic") {
		return Provider{}, 0, errors.New("provider requires a unique 3-64 character lowercase slug, name, protocol openai|anthropic, base_url, and api_key")
	}
	if (input.Protocol == "openai" && input.WireAPI != "chat_completions" && input.WireAPI != "responses") ||
		(input.Protocol == "anthropic" && input.WireAPI != "messages") {
		return Provider{}, 0, errors.New("provider wire_api is incompatible with protocol")
	}
	parsed, err := url.Parse(input.BaseURL)
	if err != nil || parsed.Host == "" || (parsed.Scheme != "http" && parsed.Scheme != "https") {
		return Provider{}, 0, errors.New("provider base_url must be an absolute http(s) URL")
	}
	ciphertext, err := s.cipher.Encrypt(input.APIKey)
	if err != nil {
		return Provider{}, 0, err
	}
	tx, err := s.db.Begin(ctx)
	if err != nil {
		return Provider{}, 0, err
	}
	defer tx.Rollback(ctx)
	var result Provider
	err = tx.QueryRow(ctx, `
		INSERT INTO providers (slug, name, protocol, wire_api, base_url, api_key_ciphertext)
		VALUES ($1, $2, $3, $4, $5, $6)
		RETURNING id::text, slug, name, protocol, wire_api, base_url, enabled, created_at`,
		input.Slug, input.Name, input.Protocol, input.WireAPI, input.BaseURL, ciphertext,
	).Scan(&result.ID, &result.Slug, &result.Name, &result.Protocol, &result.WireAPI, &result.BaseURL, &result.Enabled, &result.CreatedAt)
	if err != nil {
		return Provider{}, 0, fmt.Errorf("create provider: %w", err)
	}
	generation, err := bumpGeneration(ctx, tx)
	if err != nil {
		return Provider{}, 0, err
	}
	if err := tx.Commit(ctx); err != nil {
		return Provider{}, 0, err
	}
	return result, generation, nil
}

func (s *Store) SetProviderEnabled(ctx context.Context, id string, enabled bool) (int64, error) {
	return s.toggle(ctx, `UPDATE providers SET enabled = $2, updated_at = now() WHERE id = $1`, id, enabled)
}

func (s *Store) CreateModel(ctx context.Context, input CreateModelInput) (Model, int64, error) {
	input.PublicID = strings.TrimSpace(input.PublicID)
	input.DisplayName = strings.TrimSpace(input.DisplayName)
	input.Description = strings.TrimSpace(input.Description)
	input.OwnedBy = strings.TrimSpace(input.OwnedBy)
	input.Lifecycle = strings.ToLower(strings.TrimSpace(input.Lifecycle))
	input.PriceCurrency = strings.ToLower(strings.TrimSpace(input.PriceCurrency))
	if input.DisplayName == "" {
		input.DisplayName = input.PublicID
	}
	if input.Lifecycle == "" {
		input.Lifecycle = "active"
	}
	if input.PriceCurrency == "" {
		input.PriceCurrency = "usd"
	}
	if len(input.InputModalities) == 0 {
		input.InputModalities = []string{"text"}
	}
	if len(input.OutputModalities) == 0 {
		input.OutputModalities = []string{"text"}
	}
	if len(input.Capabilities) == 0 {
		input.Capabilities = []string{"chat", "streaming"}
	}
	input.InputModalities = uniqueStrings(input.InputModalities)
	input.OutputModalities = uniqueStrings(input.OutputModalities)
	input.Capabilities = uniqueStrings(input.Capabilities)
	input.Regions = uniqueStrings(input.Regions)
	input.Aliases = uniqueStrings(input.Aliases)
	input.AllowedTenantIDs = uniqueStrings(input.AllowedTenantIDs)
	input.AllowedKeyIDs = uniqueStrings(input.AllowedKeyIDs)
	if input.PublicID == "" || len(input.Routes) == 0 {
		return Model{}, 0, errors.New("model requires public_id and at least one route")
	}
	if input.ContextWindow < 0 || input.MaxOutputTokens < 0 || len(input.PriceCurrency) != 3 {
		return Model{}, 0, errors.New("model context, output limit, or price currency is invalid")
	}
	if input.Lifecycle != "preview" && input.Lifecycle != "active" && input.Lifecycle != "deprecated" && input.Lifecycle != "retired" {
		return Model{}, 0, errors.New("model lifecycle must be preview, active, deprecated, or retired")
	}
	if input.InputPriceMicrosPerMillion < 0 || input.OutputPriceMicrosPerMillion < 0 || input.CacheReadPriceMicrosPerMillion < 0 || input.CacheWritePriceMicrosPerMillion < 0 {
		return Model{}, 0, errors.New("model prices cannot be negative")
	}
	for i := range input.Routes {
		input.Routes[i].ProviderID = strings.TrimSpace(input.Routes[i].ProviderID)
		input.Routes[i].UpstreamModel = strings.TrimSpace(input.Routes[i].UpstreamModel)
		if input.Routes[i].Weight == 0 {
			input.Routes[i].Weight = 1
		}
		if input.Routes[i].ProviderID == "" || input.Routes[i].UpstreamModel == "" || input.Routes[i].Priority < 0 || input.Routes[i].Weight < 1 || input.Routes[i].Weight > 100 {
			return Model{}, 0, fmt.Errorf("route %d has invalid provider, upstream model, priority, or weight", i+1)
		}
	}
	tx, err := s.db.Begin(ctx)
	if err != nil {
		return Model{}, 0, err
	}
	defer tx.Rollback(ctx)
	inputModalitiesJSON, _ := json.Marshal(input.InputModalities)
	outputModalitiesJSON, _ := json.Marshal(input.OutputModalities)
	capabilitiesJSON, _ := json.Marshal(input.Capabilities)
	regionsJSON, _ := json.Marshal(input.Regions)
	var result Model
	err = tx.QueryRow(ctx, `
		INSERT INTO models (public_id, display_name, description, owned_by, input_modalities, output_modalities,
		                    context_window, max_output_tokens, capabilities, regions, lifecycle, released_at,
		                    deprecated_at, retired_at, replacement_model, input_price_micros_per_million,
		                    output_price_micros_per_million, cache_read_price_micros_per_million, cache_write_price_micros_per_million)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,NULLIF($15,''),$16,$17,$18,$19)
		RETURNING id::text, public_id, display_name, description, owned_by,
		          input_price_micros_per_million, output_price_micros_per_million,
		          cache_read_price_micros_per_million, cache_write_price_micros_per_million, enabled, created_at`,
		input.PublicID, input.DisplayName, input.Description, input.OwnedBy, inputModalitiesJSON, outputModalitiesJSON,
		input.ContextWindow, input.MaxOutputTokens, capabilitiesJSON, regionsJSON, input.Lifecycle,
		input.ReleasedAt, input.DeprecatedAt, input.RetiredAt, input.ReplacementModel,
		input.InputPriceMicrosPerMillion, input.OutputPriceMicrosPerMillion,
		input.CacheReadPriceMicrosPerMillion, input.CacheWritePriceMicrosPerMillion,
	).Scan(&result.ID, &result.PublicID, &result.DisplayName, &result.Description, &result.OwnedBy, &result.InputPriceMicrosPerMillion,
		&result.OutputPriceMicrosPerMillion, &result.CacheReadPriceMicrosPerMillion,
		&result.CacheWritePriceMicrosPerMillion, &result.Enabled, &result.CreatedAt)
	if err != nil {
		return Model{}, 0, fmt.Errorf("create model: %w", err)
	}
	result.InputModalities, result.OutputModalities = input.InputModalities, input.OutputModalities
	result.ContextWindow, result.MaxOutputTokens = input.ContextWindow, input.MaxOutputTokens
	result.Capabilities, result.Regions, result.Lifecycle = input.Capabilities, input.Regions, input.Lifecycle
	result.ReleasedAt, result.DeprecatedAt, result.RetiredAt = input.ReleasedAt, input.DeprecatedAt, input.RetiredAt
	result.ReplacementModel, result.Aliases = input.ReplacementModel, input.Aliases
	result.AllowedTenantIDs, result.AllowedKeyIDs = input.AllowedTenantIDs, input.AllowedKeyIDs
	result.PriceCurrency, result.PriceVersion = input.PriceCurrency, 1
	err = tx.QueryRow(ctx, `INSERT INTO model_price_versions (model_id,version,currency,
		input_price_micros_per_million,output_price_micros_per_million,
		cache_read_price_micros_per_million,cache_write_price_micros_per_million)
		VALUES ($1,1,$2,$3,$4,$5,$6) RETURNING id::text,effective_from`, result.ID, input.PriceCurrency,
		input.InputPriceMicrosPerMillion, input.OutputPriceMicrosPerMillion,
		input.CacheReadPriceMicrosPerMillion, input.CacheWritePriceMicrosPerMillion,
	).Scan(&result.PriceVersionID, &result.PriceEffectiveFrom)
	if err != nil {
		return Model{}, 0, fmt.Errorf("create model price version: %w", err)
	}
	for _, alias := range input.Aliases {
		if _, err := tx.Exec(ctx, `INSERT INTO model_aliases (alias,model_id,deprecated) VALUES ($1,$2,true)`, alias, result.ID); err != nil {
			return Model{}, 0, fmt.Errorf("create model alias: %w", err)
		}
	}
	for _, tenantID := range input.AllowedTenantIDs {
		if _, err := tx.Exec(ctx, `INSERT INTO model_tenant_allowlist (model_id,tenant_id) VALUES ($1,$2)`, result.ID, tenantID); err != nil {
			return Model{}, 0, fmt.Errorf("create tenant model allowlist: %w", err)
		}
	}
	for _, keyID := range input.AllowedKeyIDs {
		if _, err := tx.Exec(ctx, `INSERT INTO api_key_model_allowlist (api_key_id,model_id) VALUES ($1,$2)`, keyID, result.ID); err != nil {
			return Model{}, 0, fmt.Errorf("create key model allowlist: %w", err)
		}
	}
	result.Routes = make([]Route, 0, len(input.Routes))
	for _, route := range input.Routes {
		var created Route
		err := tx.QueryRow(ctx, `
			INSERT INTO model_routes (model_id, provider_id, upstream_model, priority, weight)
			VALUES ($1, $2, $3, $4, $5)
			RETURNING id::text, provider_id::text, upstream_model, priority, weight, enabled`,
			result.ID, route.ProviderID, route.UpstreamModel, route.Priority, route.Weight,
		).Scan(&created.ID, &created.ProviderID, &created.UpstreamModel, &created.Priority, &created.Weight, &created.Enabled)
		if err != nil {
			return Model{}, 0, fmt.Errorf("create model route: %w", err)
		}
		result.Routes = append(result.Routes, created)
	}
	generation, err := bumpGeneration(ctx, tx)
	if err != nil {
		return Model{}, 0, err
	}
	if err := tx.Commit(ctx); err != nil {
		return Model{}, 0, err
	}
	return result, generation, nil
}

func (s *Store) CreateModelPriceVersion(ctx context.Context, modelID string, input CreatePriceVersionInput) (int64, error) {
	input.Currency = strings.ToLower(strings.TrimSpace(input.Currency))
	if len(input.Currency) != 3 || input.InputPriceMicrosPerMillion < 0 || input.OutputPriceMicrosPerMillion < 0 ||
		input.CacheReadPriceMicrosPerMillion < 0 || input.CacheWritePriceMicrosPerMillion < 0 {
		return 0, errors.New("price version has invalid currency or negative price")
	}
	if input.EffectiveFrom.IsZero() {
		input.EffectiveFrom = time.Now().UTC()
	}
	tx, err := s.db.Begin(ctx)
	if err != nil {
		return 0, err
	}
	defer tx.Rollback(ctx)
	// Lock the model row before allocating the next version. PostgreSQL does
	// not allow FOR UPDATE on an aggregate query.
	var modelExists bool
	if err := tx.QueryRow(ctx, `SELECT true FROM models WHERE id=$1 FOR UPDATE`, modelID).Scan(&modelExists); errors.Is(err, pgx.ErrNoRows) {
		return 0, ErrNotFound
	} else if err != nil {
		return 0, err
	}
	var currentEffectiveFrom time.Time
	err = tx.QueryRow(ctx, `SELECT effective_from FROM model_price_versions WHERE model_id=$1 AND effective_to IS NULL`, modelID).Scan(&currentEffectiveFrom)
	if err != nil && !errors.Is(err, pgx.ErrNoRows) {
		return 0, err
	}
	if err == nil && !input.EffectiveFrom.After(currentEffectiveFrom) {
		return 0, errors.New("new price version must become effective after the current open version")
	}
	var version int
	if err := tx.QueryRow(ctx, `SELECT COALESCE(max(version),0)+1 FROM model_price_versions WHERE model_id=$1`, modelID).Scan(&version); err != nil {
		return 0, err
	}
	if _, err := tx.Exec(ctx, `UPDATE model_price_versions SET effective_to=$2 WHERE model_id=$1 AND effective_to IS NULL AND effective_from < $2`, modelID, input.EffectiveFrom); err != nil {
		return 0, err
	}
	if _, err := tx.Exec(ctx, `INSERT INTO model_price_versions (model_id,version,currency,input_price_micros_per_million,
		output_price_micros_per_million,cache_read_price_micros_per_million,cache_write_price_micros_per_million,effective_from)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8)`, modelID, version, input.Currency, input.InputPriceMicrosPerMillion,
		input.OutputPriceMicrosPerMillion, input.CacheReadPriceMicrosPerMillion, input.CacheWritePriceMicrosPerMillion, input.EffectiveFrom); err != nil {
		return 0, err
	}
	generation, err := bumpGeneration(ctx, tx)
	if err != nil {
		return 0, err
	}
	if err := tx.Commit(ctx); err != nil {
		return 0, err
	}
	return generation, nil
}

func (s *Store) SetModelEnabled(ctx context.Context, id string, enabled bool) (int64, error) {
	return s.toggle(ctx, `UPDATE models SET enabled = $2, updated_at = now() WHERE id = $1`, id, enabled)
}

func (s *Store) toggle(ctx context.Context, query, id string, args ...any) (int64, error) {
	tx, err := s.db.Begin(ctx)
	if err != nil {
		return 0, err
	}
	defer tx.Rollback(ctx)
	parameters := append([]any{id}, args...)
	command, err := tx.Exec(ctx, query, parameters...)
	if err != nil {
		return 0, err
	}
	if command.RowsAffected() == 0 {
		return 0, ErrNotFound
	}
	generation, err := bumpGeneration(ctx, tx)
	if err != nil {
		return 0, err
	}
	if err := tx.Commit(ctx); err != nil {
		return 0, err
	}
	return generation, nil
}

func bumpGeneration(ctx context.Context, tx pgx.Tx) (int64, error) {
	var generation int64
	err := tx.QueryRow(ctx, `
		UPDATE control_state SET generation = generation + 1, updated_at = now()
		WHERE singleton = TRUE RETURNING generation`,
	).Scan(&generation)
	if err != nil {
		return 0, fmt.Errorf("advance control-plane generation: %w", err)
	}
	return generation, nil
}

func uniqueStrings(values []string) []string {
	seen := make(map[string]struct{}, len(values))
	result := make([]string, 0, len(values))
	for _, value := range values {
		value = strings.TrimSpace(value)
		if value == "" {
			continue
		}
		if _, exists := seen[value]; exists {
			continue
		}
		seen[value] = struct{}{}
		result = append(result, value)
	}
	return result
}