package store

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

	"github.com/easyai/easyai-ai-gateway/apps/api/internal/auth"
	"github.com/jackc/pgx/v5"
)

const SystemSettingGatewayTrafficMode = "gateway_traffic_mode"

var (
	acceptanceReleaseSHAPattern = regexp.MustCompile(`^[0-9a-f]{40}$`)
	acceptanceDigestPattern     = regexp.MustCompile(`^sha256:[0-9a-f]{64}$`)
)

var (
	ErrProductionTrafficPaused  = errors.New("production traffic is paused for validation")
	ErrAcceptanceNotAuthorized  = errors.New("acceptance request is not authorized")
	ErrAcceptanceRunNotActive   = errors.New("acceptance run is not active")
	ErrAcceptanceStateConflict  = errors.New("acceptance state changed")
	ErrAcceptancePromotionGates = errors.New("acceptance promotion gates have not passed")
)

type GatewayTrafficMode struct {
	Mode              string    `json:"mode"`
	RunID             string    `json:"runId,omitempty"`
	Revision          int64     `json:"revision"`
	ReleaseSHA        string    `json:"releaseSha,omitempty"`
	APIImageDigest    string    `json:"apiImageDigest,omitempty"`
	WorkerImageDigest string    `json:"workerImageDigest,omitempty"`
	UpdatedAt         time.Time `json:"updatedAt"`
}

type AcceptanceRun struct {
	ID                string         `json:"id"`
	Status            string         `json:"status"`
	ReleaseSHA        string         `json:"releaseSha"`
	APIImageDigest    string         `json:"apiImageDigest"`
	WorkerImageDigest string         `json:"workerImageDigest"`
	APIKeyID          string         `json:"apiKeyId"`
	UserID            string         `json:"userId"`
	EmulatorBaseURL   string         `json:"emulatorBaseUrl"`
	CallbackURL       string         `json:"callbackUrl,omitempty"`
	CapacityProfile   string         `json:"capacityProfile"`
	Config            map[string]any `json:"config"`
	Report            map[string]any `json:"report"`
	FailureReason     string         `json:"failureReason,omitempty"`
	StartedAt         string         `json:"startedAt,omitempty"`
	FinishedAt        string         `json:"finishedAt,omitempty"`
	PromotedAt        string         `json:"promotedAt,omitempty"`
	CreatedAt         time.Time      `json:"createdAt"`
	UpdatedAt         time.Time      `json:"updatedAt"`
}

type CreateAcceptanceRunInput struct {
	ReleaseSHA        string         `json:"releaseSha"`
	APIImageDigest    string         `json:"apiImageDigest"`
	WorkerImageDigest string         `json:"workerImageDigest"`
	APIKeyID          string         `json:"apiKeyId"`
	UserID            string         `json:"userId"`
	Token             string         `json:"token"`
	EmulatorBaseURL   string         `json:"emulatorBaseUrl"`
	CallbackURL       string         `json:"callbackUrl,omitempty"`
	CapacityProfile   string         `json:"capacityProfile"`
	Config            map[string]any `json:"config,omitempty"`
}

type FinishAcceptanceRunInput struct {
	RunID         string         `json:"-"`
	Passed        bool           `json:"passed"`
	Report        map[string]any `json:"report"`
	FailureReason string         `json:"failureReason,omitempty"`
}

type PromoteAcceptanceRunInput struct {
	RunID             string `json:"-"`
	Revision          int64  `json:"revision"`
	ReleaseSHA        string `json:"releaseSha"`
	APIImageDigest    string `json:"apiImageDigest"`
	WorkerImageDigest string `json:"workerImageDigest"`
}

func DefaultGatewayTrafficMode() GatewayTrafficMode {
	return GatewayTrafficMode{Mode: "live"}
}

func (s *Store) GetGatewayTrafficMode(ctx context.Context) (GatewayTrafficMode, error) {
	var value []byte
	var updatedAt time.Time
	err := s.pool.QueryRow(ctx, `
SELECT value, updated_at
FROM system_settings
WHERE setting_key = $1`, SystemSettingGatewayTrafficMode).Scan(&value, &updatedAt)
	if err != nil {
		if IsNotFound(err) || IsUndefinedDatabaseObject(err) {
			return DefaultGatewayTrafficMode(), nil
		}
		return GatewayTrafficMode{}, err
	}
	var mode GatewayTrafficMode
	if err := json.Unmarshal(value, &mode); err != nil {
		return GatewayTrafficMode{}, fmt.Errorf("decode gateway traffic mode: %w", err)
	}
	mode.Mode = normalizeTrafficMode(mode.Mode)
	mode.UpdatedAt = updatedAt
	return mode, nil
}

func (s *Store) CreateAcceptanceRun(ctx context.Context, input CreateAcceptanceRunInput) (AcceptanceRun, error) {
	input.ReleaseSHA = strings.TrimSpace(input.ReleaseSHA)
	input.APIImageDigest = strings.TrimSpace(input.APIImageDigest)
	input.WorkerImageDigest = strings.TrimSpace(input.WorkerImageDigest)
	input.APIKeyID = strings.TrimSpace(input.APIKeyID)
	input.UserID = strings.TrimSpace(input.UserID)
	input.Token = strings.TrimSpace(input.Token)
	input.EmulatorBaseURL = strings.TrimRight(strings.TrimSpace(input.EmulatorBaseURL), "/")
	input.CallbackURL = strings.TrimSpace(input.CallbackURL)
	input.CapacityProfile = strings.ToUpper(strings.TrimSpace(input.CapacityProfile))
	if input.CapacityProfile == "" {
		input.CapacityProfile = "P24"
	}
	if input.ReleaseSHA == "" || input.APIImageDigest == "" || input.WorkerImageDigest == "" ||
		input.APIKeyID == "" || input.UserID == "" || input.Token == "" || input.EmulatorBaseURL == "" ||
		input.CallbackURL == "" {
		return AcceptanceRun{}, errors.New("release SHA, image digests, API key, user, token, emulator URL, and callback URL are required")
	}
	if !acceptanceReleaseSHAPattern.MatchString(input.ReleaseSHA) ||
		!acceptanceDigestPattern.MatchString(input.APIImageDigest) ||
		!acceptanceDigestPattern.MatchString(input.WorkerImageDigest) {
		return AcceptanceRun{}, errors.New("release SHA and image digests must use full immutable identifiers")
	}
	if len(input.Token) < 32 {
		return AcceptanceRun{}, errors.New("acceptance token must contain at least 32 characters")
	}
	if !validAcceptanceURL(input.EmulatorBaseURL) || !validAcceptanceURL(input.CallbackURL) {
		return AcceptanceRun{}, errors.New("emulator and callback URLs must be absolute HTTP URLs without user information")
	}
	switch input.CapacityProfile {
	case "P24", "P28", "P32":
	default:
		return AcceptanceRun{}, errors.New("capacity profile must be P24, P28, or P32")
	}
	config, _ := json.Marshal(sanitizeAcceptanceMetadata(sanitizeJSONForStorage(input.Config)))
	tokenHash := acceptanceTokenSHA256(input.Token)
	return scanAcceptanceRun(s.pool.QueryRow(ctx, `
INSERT INTO gateway_acceptance_runs (
  release_sha, api_image_digest, worker_image_digest, api_key_id, user_id,
  token_sha256, emulator_base_url, callback_url, capacity_profile, config
)
VALUES ($1, $2, $3, $4, $5, $6, $7, NULLIF($8, ''), $9, $10::jsonb)
RETURNING `+acceptanceRunColumns,
		input.ReleaseSHA, input.APIImageDigest, input.WorkerImageDigest, input.APIKeyID, input.UserID,
		tokenHash, input.EmulatorBaseURL, input.CallbackURL, input.CapacityProfile, config,
	))
}

func (s *Store) GetAcceptanceRun(ctx context.Context, runID string) (AcceptanceRun, error) {
	return scanAcceptanceRun(s.pool.QueryRow(ctx, `
SELECT `+acceptanceRunColumns+`
FROM gateway_acceptance_runs
WHERE id = $1::uuid`, strings.TrimSpace(runID)))
}

func (s *Store) ActivateAcceptanceRun(ctx context.Context, runID string) (GatewayTrafficMode, error) {
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return GatewayTrafficMode{}, err
	}
	defer rollbackTransaction(tx)

	var currentValue []byte
	if err := tx.QueryRow(ctx, `
SELECT value
FROM system_settings
WHERE setting_key = $1
FOR UPDATE`, SystemSettingGatewayTrafficMode).Scan(&currentValue); err != nil {
		return GatewayTrafficMode{}, err
	}
	var current GatewayTrafficMode
	if err := json.Unmarshal(currentValue, &current); err != nil {
		return GatewayTrafficMode{}, err
	}
	if normalizeTrafficMode(current.Mode) != "live" {
		return GatewayTrafficMode{}, ErrAcceptanceStateConflict
	}
	run, err := scanAcceptanceRun(tx.QueryRow(ctx, `
SELECT `+acceptanceRunColumns+`
FROM gateway_acceptance_runs
WHERE id = $1::uuid
FOR UPDATE`, strings.TrimSpace(runID)))
	if err != nil {
		return GatewayTrafficMode{}, err
	}
	if run.Status != "pending" && run.Status != "failed" {
		return GatewayTrafficMode{}, ErrAcceptanceStateConflict
	}
	next := GatewayTrafficMode{
		Mode:              "validation",
		RunID:             run.ID,
		Revision:          current.Revision + 1,
		ReleaseSHA:        run.ReleaseSHA,
		APIImageDigest:    run.APIImageDigest,
		WorkerImageDigest: run.WorkerImageDigest,
	}
	value, _ := json.Marshal(next)
	if _, err := tx.Exec(ctx, `
UPDATE system_settings
SET value = $2::jsonb, updated_at = now()
WHERE setting_key = $1`, SystemSettingGatewayTrafficMode, value); err != nil {
		return GatewayTrafficMode{}, err
	}
	if _, err := tx.Exec(ctx, `
UPDATE gateway_acceptance_runs
SET status = 'running', started_at = COALESCE(started_at, now()),
    finished_at = NULL, failure_reason = NULL, updated_at = now()
WHERE id = $1::uuid`, run.ID); err != nil {
		return GatewayTrafficMode{}, err
	}
	if err := tx.Commit(ctx); err != nil {
		return GatewayTrafficMode{}, err
	}
	next.UpdatedAt = time.Now()
	return next, nil
}

func (s *Store) FinishAcceptanceRun(ctx context.Context, input FinishAcceptanceRunInput) (AcceptanceRun, error) {
	status := "failed"
	if input.Passed {
		status = "passed"
	}
	report, _ := json.Marshal(sanitizeAcceptanceMetadata(sanitizeJSONForStorage(input.Report)))
	return scanAcceptanceRun(s.pool.QueryRow(ctx, `
UPDATE gateway_acceptance_runs
SET status = $2, report = $3::jsonb, failure_reason = NULLIF($4, ''),
    finished_at = now(), updated_at = now()
WHERE id = $1::uuid AND status = 'running'
RETURNING `+acceptanceRunColumns,
		strings.TrimSpace(input.RunID), status, report, strings.TrimSpace(input.FailureReason),
	))
}

func (s *Store) RetryAcceptanceRun(ctx context.Context, runID string) (AcceptanceRun, error) {
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return AcceptanceRun{}, err
	}
	defer rollbackTransaction(tx)
	var value []byte
	if err := tx.QueryRow(ctx, `
SELECT value
FROM system_settings
WHERE setting_key = $1
FOR UPDATE`, SystemSettingGatewayTrafficMode).Scan(&value); err != nil {
		return AcceptanceRun{}, err
	}
	var mode GatewayTrafficMode
	if err := json.Unmarshal(value, &mode); err != nil {
		return AcceptanceRun{}, err
	}
	if normalizeTrafficMode(mode.Mode) != "validation" || mode.RunID != strings.TrimSpace(runID) {
		return AcceptanceRun{}, ErrAcceptanceStateConflict
	}
	run, err := scanAcceptanceRun(tx.QueryRow(ctx, `
UPDATE gateway_acceptance_runs
SET status = 'running', report = '{}'::jsonb, failure_reason = NULL,
    finished_at = NULL, updated_at = now()
WHERE id = $1::uuid AND status = 'failed'
RETURNING `+acceptanceRunColumns, strings.TrimSpace(runID)))
	if err != nil {
		return AcceptanceRun{}, err
	}
	if err := tx.Commit(ctx); err != nil {
		return AcceptanceRun{}, err
	}
	return run, nil
}

func (s *Store) PromoteAcceptanceRun(ctx context.Context, input PromoteAcceptanceRunInput) (GatewayTrafficMode, error) {
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return GatewayTrafficMode{}, err
	}
	defer rollbackTransaction(tx)
	var value []byte
	if err := tx.QueryRow(ctx, `
SELECT value
FROM system_settings
WHERE setting_key = $1
FOR UPDATE`, SystemSettingGatewayTrafficMode).Scan(&value); err != nil {
		return GatewayTrafficMode{}, err
	}
	var current GatewayTrafficMode
	if err := json.Unmarshal(value, &current); err != nil {
		return GatewayTrafficMode{}, err
	}
	if normalizeTrafficMode(current.Mode) != "validation" ||
		current.RunID != strings.TrimSpace(input.RunID) ||
		current.Revision != input.Revision ||
		current.ReleaseSHA != strings.TrimSpace(input.ReleaseSHA) ||
		current.APIImageDigest != strings.TrimSpace(input.APIImageDigest) ||
		current.WorkerImageDigest != strings.TrimSpace(input.WorkerImageDigest) {
		return GatewayTrafficMode{}, ErrAcceptanceStateConflict
	}
	var status string
	if err := tx.QueryRow(ctx, `
SELECT status
FROM gateway_acceptance_runs
WHERE id = $1::uuid
FOR UPDATE`, current.RunID).Scan(&status); err != nil {
		return GatewayTrafficMode{}, err
	}
	if status != "passed" {
		return GatewayTrafficMode{}, ErrAcceptancePromotionGates
	}
	next := GatewayTrafficMode{Mode: "live", Revision: current.Revision + 1}
	nextValue, _ := json.Marshal(next)
	if _, err := tx.Exec(ctx, `
UPDATE system_settings
SET value = $2::jsonb, updated_at = now()
WHERE setting_key = $1`, SystemSettingGatewayTrafficMode, nextValue); err != nil {
		return GatewayTrafficMode{}, err
	}
	if _, err := tx.Exec(ctx, `
UPDATE gateway_acceptance_runs
SET status = 'promoted', promoted_at = now(), updated_at = now()
WHERE id = $1::uuid`, current.RunID); err != nil {
		return GatewayTrafficMode{}, err
	}
	if err := tx.Commit(ctx); err != nil {
		return GatewayTrafficMode{}, err
	}
	next.UpdatedAt = time.Now()
	return next, nil
}

func (s *Store) AbortAcceptanceRun(ctx context.Context, input PromoteAcceptanceRunInput) (GatewayTrafficMode, error) {
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return GatewayTrafficMode{}, err
	}
	defer rollbackTransaction(tx)
	var value []byte
	if err := tx.QueryRow(ctx, `
SELECT value
FROM system_settings
WHERE setting_key = $1
FOR UPDATE`, SystemSettingGatewayTrafficMode).Scan(&value); err != nil {
		return GatewayTrafficMode{}, err
	}
	var current GatewayTrafficMode
	if err := json.Unmarshal(value, &current); err != nil {
		return GatewayTrafficMode{}, err
	}
	if normalizeTrafficMode(current.Mode) != "validation" ||
		current.RunID != strings.TrimSpace(input.RunID) ||
		current.Revision != input.Revision ||
		current.ReleaseSHA != strings.TrimSpace(input.ReleaseSHA) ||
		current.APIImageDigest != strings.TrimSpace(input.APIImageDigest) ||
		current.WorkerImageDigest != strings.TrimSpace(input.WorkerImageDigest) {
		return GatewayTrafficMode{}, ErrAcceptanceStateConflict
	}
	next := GatewayTrafficMode{Mode: "live", Revision: current.Revision + 1}
	nextValue, _ := json.Marshal(next)
	if _, err := tx.Exec(ctx, `
UPDATE system_settings
SET value = $2::jsonb, updated_at = now()
WHERE setting_key = $1`, SystemSettingGatewayTrafficMode, nextValue); err != nil {
		return GatewayTrafficMode{}, err
	}
	if _, err := tx.Exec(ctx, `
UPDATE gateway_acceptance_runs
SET status = 'aborted', finished_at = COALESCE(finished_at, now()), updated_at = now()
WHERE id = $1::uuid AND status IN ('running', 'failed', 'passed')`, current.RunID); err != nil {
		return GatewayTrafficMode{}, err
	}
	if err := tx.Commit(ctx); err != nil {
		return GatewayTrafficMode{}, err
	}
	next.UpdatedAt = time.Now()
	return next, nil
}

func (s *Store) AuthorizeAcceptanceTask(ctx context.Context, runID string, token string, user *auth.User) (string, error) {
	mode, err := s.GetGatewayTrafficMode(ctx)
	if err != nil {
		return "", err
	}
	runID = strings.TrimSpace(runID)
	token = strings.TrimSpace(token)
	if mode.Mode == "live" {
		if runID != "" || token != "" {
			return "", ErrAcceptanceRunNotActive
		}
		return "", nil
	}
	if runID == "" || token == "" || runID != mode.RunID {
		return "", ErrProductionTrafficPaused
	}
	if user == nil || strings.TrimSpace(user.APIKeyID) == "" {
		return "", ErrAcceptanceNotAuthorized
	}
	var activeRunID, apiKeyID, userID, tokenHash, status string
	err = s.pool.QueryRow(ctx, `
SELECT id::text, api_key_id, user_id, token_sha256, status
FROM gateway_acceptance_runs
WHERE id = $1::uuid`, runID).Scan(&activeRunID, &apiKeyID, &userID, &tokenHash, &status)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return "", ErrAcceptanceNotAuthorized
		}
		return "", err
	}
	if status != "running" || apiKeyID != strings.TrimSpace(user.APIKeyID) || userID != strings.TrimSpace(user.ID) ||
		subtle.ConstantTimeCompare([]byte(tokenHash), []byte(acceptanceTokenSHA256(token))) != 1 {
		return "", ErrAcceptanceNotAuthorized
	}
	return activeRunID, nil
}

func (s *Store) AcceptanceCandidateOverride(ctx context.Context, runID string) (string, string, error) {
	var baseURL, status string
	err := s.pool.QueryRow(ctx, `
SELECT emulator_base_url, status
FROM gateway_acceptance_runs
WHERE id = $1::uuid`, strings.TrimSpace(runID)).Scan(&baseURL, &status)
	if err != nil {
		return "", "", err
	}
	if status != "running" && status != "passed" {
		return "", "", ErrAcceptanceRunNotActive
	}
	return strings.TrimRight(strings.TrimSpace(baseURL), "/"), "acceptance-protocol-emulator", nil
}

func (s *Store) AcceptanceCallbackURL(ctx context.Context, taskID string) (string, bool, error) {
	var callbackURL string
	err := s.pool.QueryRow(ctx, `
SELECT COALESCE(run.callback_url, '')
FROM gateway_tasks task
JOIN gateway_acceptance_runs run ON run.id = task.acceptance_run_id
WHERE task.id = $1::uuid`, strings.TrimSpace(taskID)).Scan(&callbackURL)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return "", false, nil
		}
		return "", false, err
	}
	return strings.TrimSpace(callbackURL), true, nil
}

func normalizeTrafficMode(value string) string {
	if strings.EqualFold(strings.TrimSpace(value), "validation") {
		return "validation"
	}
	return "live"
}

func acceptanceTokenSHA256(token string) string {
	sum := sha256.Sum256([]byte(strings.TrimSpace(token)))
	return hex.EncodeToString(sum[:])
}

func validAcceptanceURL(raw string) bool {
	parsed, err := url.Parse(strings.TrimSpace(raw))
	if err != nil || parsed.User != nil || parsed.Host == "" {
		return false
	}
	return parsed.Scheme == "http" || parsed.Scheme == "https"
}

func sanitizeAcceptanceMetadata(value any) any {
	switch typed := value.(type) {
	case map[string]any:
		next := make(map[string]any, len(typed))
		for key, item := range typed {
			normalized := strings.ToLower(strings.NewReplacer("_", "", "-", "", ".", "").Replace(key))
			if strings.Contains(normalized, "password") ||
				strings.Contains(normalized, "secret") ||
				strings.Contains(normalized, "credential") ||
				strings.Contains(normalized, "connectionstring") ||
				strings.Contains(normalized, "databaseurl") ||
				(strings.Contains(normalized, "token") && !strings.HasSuffix(normalized, "count")) {
				next[key] = "[REDACTED]"
				continue
			}
			next[key] = sanitizeAcceptanceMetadata(item)
		}
		return next
	case []any:
		next := make([]any, len(typed))
		for index, item := range typed {
			next[index] = sanitizeAcceptanceMetadata(item)
		}
		return next
	default:
		return value
	}
}

const acceptanceRunColumns = `
id::text, status, release_sha, api_image_digest, worker_image_digest,
api_key_id, user_id, emulator_base_url, COALESCE(callback_url, ''),
capacity_profile, config, report, COALESCE(failure_reason, ''),
COALESCE(started_at::text, ''), COALESCE(finished_at::text, ''),
COALESCE(promoted_at::text, ''), created_at, updated_at`

func scanAcceptanceRun(scanner taskScanner) (AcceptanceRun, error) {
	var run AcceptanceRun
	var config, report []byte
	err := scanner.Scan(
		&run.ID, &run.Status, &run.ReleaseSHA, &run.APIImageDigest, &run.WorkerImageDigest,
		&run.APIKeyID, &run.UserID, &run.EmulatorBaseURL, &run.CallbackURL,
		&run.CapacityProfile, &config, &report, &run.FailureReason,
		&run.StartedAt, &run.FinishedAt, &run.PromotedAt, &run.CreatedAt, &run.UpdatedAt,
	)
	if err != nil {
		return AcceptanceRun{}, err
	}
	run.Config = decodeObject(config)
	run.Report = decodeObject(report)
	return run, nil
}