package store

import (
	"context"
	"encoding/json"
)

func (s *Store) MarkTaskRunning(ctx context.Context, taskID string, modelType string, normalizedRequest map[string]any) error {
	normalizedJSON, _ := json.Marshal(emptyObjectIfNil(normalizedRequest))
	_, err := s.pool.Exec(ctx, `
UPDATE gateway_tasks
SET status = 'running',
    model_type = NULLIF($2, ''),
    normalized_request = $3::jsonb,
    locked_at = now(),
    heartbeat_at = now(),
    updated_at = now()
WHERE id = $1::uuid`, taskID, modelType, string(normalizedJSON))
	return err
}

func (s *Store) CreateTaskAttempt(ctx context.Context, input CreateTaskAttemptInput) (string, error) {
	requestJSON, _ := json.Marshal(emptyObjectIfNil(input.RequestSnapshot))
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return "", err
	}
	defer tx.Rollback(ctx)

	var attemptID string
	err = tx.QueryRow(ctx, `
INSERT INTO gateway_task_attempts (
  task_id, attempt_no, platform_id, platform_model_id, client_id, queue_key,
  status, simulated, request_snapshot
)
VALUES (
  $1::uuid, $2, NULLIF($3, '')::uuid, NULLIF($4, '')::uuid, NULLIF($5, ''), $6,
  $7, $8, $9::jsonb
)
RETURNING id::text`,
		input.TaskID,
		input.AttemptNo,
		input.PlatformID,
		input.PlatformModelID,
		input.ClientID,
		input.QueueKey,
		firstNonEmpty(input.Status, "running"),
		input.Simulated,
		string(requestJSON),
	).Scan(&attemptID)
	if err != nil {
		return "", err
	}
	if _, err := tx.Exec(ctx, `
UPDATE gateway_tasks
SET attempt_count = GREATEST(attempt_count, $2), updated_at = now()
WHERE id = $1::uuid`, input.TaskID, input.AttemptNo); err != nil {
		return "", err
	}
	return attemptID, tx.Commit(ctx)
}

func (s *Store) FinishTaskAttempt(ctx context.Context, input FinishTaskAttemptInput) error {
	responseJSON, _ := json.Marshal(emptyObjectIfNil(input.ResponseSnapshot))
	_, err := s.pool.Exec(ctx, `
UPDATE gateway_task_attempts
SET status = $2,
    retryable = $3,
    response_snapshot = $4::jsonb,
    error_code = NULLIF($5, ''),
    error_message = NULLIF($6, ''),
    finished_at = now()
WHERE id = $1::uuid`,
		input.AttemptID,
		input.Status,
		input.Retryable,
		string(responseJSON),
		input.ErrorCode,
		input.ErrorMessage,
	)
	return err
}

func (s *Store) FinishTaskSuccess(ctx context.Context, taskID string, result map[string]any, billings []any) (GatewayTask, error) {
	resultJSON, _ := json.Marshal(emptyObjectIfNil(result))
	billingsJSON, _ := json.Marshal(billings)
	if _, err := s.pool.Exec(ctx, `
UPDATE gateway_tasks
SET status = 'succeeded',
    result = $2::jsonb,
    billings = $3::jsonb,
    error = NULL,
    error_code = NULL,
    error_message = NULL,
    finished_at = now(),
    updated_at = now()
WHERE id = $1::uuid`, taskID, string(resultJSON), string(billingsJSON)); err != nil {
		return GatewayTask{}, err
	}
	return s.GetTask(ctx, taskID)
}

func (s *Store) FinishTaskFailure(ctx context.Context, taskID string, code string, message string) (GatewayTask, error) {
	if _, err := s.pool.Exec(ctx, `
UPDATE gateway_tasks
SET status = 'failed',
    error = NULLIF($2, ''),
    error_code = NULLIF($3, ''),
    error_message = NULLIF($2, ''),
    finished_at = now(),
    updated_at = now()
WHERE id = $1::uuid`, taskID, message, code); err != nil {
		return GatewayTask{}, err
	}
	return s.GetTask(ctx, taskID)
}

func (s *Store) AddTaskEvent(ctx context.Context, taskID string, eventType string, status string, phase string, progress float64, message string, payload map[string]any, simulated bool) (TaskEvent, error) {
	payloadJSON, _ := json.Marshal(emptyObjectIfNil(payload))
	var event TaskEvent
	var payloadBytes []byte
	err := s.pool.QueryRow(ctx, `
WITH next_seq AS (
  SELECT COALESCE(MAX(seq), 0) + 1 AS seq
  FROM gateway_task_events
  WHERE task_id = $1::uuid
)
INSERT INTO gateway_task_events (task_id, seq, event_type, status, phase, progress, message, payload, simulated)
SELECT $1::uuid, next_seq.seq, $2, NULLIF($3, ''), NULLIF($4, ''), $5, NULLIF($6, ''), $7::jsonb, $8
FROM next_seq
RETURNING id::text, task_id::text, seq, event_type, COALESCE(status, ''), COALESCE(phase, ''),
          COALESCE(progress, 0)::float8, COALESCE(message, ''), payload, simulated, created_at`,
		taskID,
		eventType,
		status,
		phase,
		progress,
		message,
		string(payloadJSON),
		simulated,
	).Scan(
		&event.ID,
		&event.TaskID,
		&event.Seq,
		&event.EventType,
		&event.Status,
		&event.Phase,
		&event.Progress,
		&event.Message,
		&payloadBytes,
		&event.Simulated,
		&event.CreatedAt,
	)
	if err != nil {
		return TaskEvent{}, err
	}
	event.Payload = decodeObject(payloadBytes)
	return event, nil
}

func (s *Store) QueueTaskCallback(ctx context.Context, event TaskEvent, callbackURL string) error {
	if callbackURL == "" {
		return nil
	}
	payloadJSON, _ := json.Marshal(map[string]any{
		"taskId":    event.TaskID,
		"seq":       event.Seq,
		"eventType": event.EventType,
		"status":    event.Status,
		"phase":     event.Phase,
		"progress":  event.Progress,
		"message":   event.Message,
		"payload":   event.Payload,
		"simulated": event.Simulated,
		"createdAt": event.CreatedAt,
	})
	_, err := s.pool.Exec(ctx, `
INSERT INTO gateway_task_callback_outbox (task_id, event_id, seq, callback_url, payload)
VALUES ($1::uuid, $2::uuid, $3, $4, $5::jsonb)
ON CONFLICT (task_id, seq, callback_url) DO NOTHING`,
		event.TaskID,
		event.ID,
		event.Seq,
		callbackURL,
		string(payloadJSON),
	)
	return err
}

func (s *Store) RecordClientAssignment(ctx context.Context, candidate RuntimeModelCandidate) error {
	_, err := s.pool.Exec(ctx, `
INSERT INTO runtime_client_states (
  client_id, platform_id, provider, method_name, queue_key, running_count, last_assigned_at
)
VALUES ($1, $2::uuid, $3, $4, $5, 1, now())
ON CONFLICT (client_id) DO UPDATE
SET running_count = runtime_client_states.running_count + 1,
    last_assigned_at = now(),
    updated_at = now()`,
		candidate.ClientID,
		candidate.PlatformID,
		candidate.Provider,
		candidate.ModelType,
		candidate.QueueKey,
	)
	return err
}

func (s *Store) RecordClientRelease(ctx context.Context, clientID string, lastError string) error {
	_, err := s.pool.Exec(ctx, `
UPDATE runtime_client_states
SET running_count = GREATEST(running_count - 1, 0),
    last_error = NULLIF($2, ''),
    updated_at = now()
WHERE client_id = $1`, clientID, lastError)
	return err
}