package platform

import (
	"database/sql"
	"encoding/json"
	"net/http"
)

type canvasAIRequest struct {
	Key, Hash, Action, Board, Run, Operation string
}

// The workspace lock is acquired by the caller before this savepoint. Rejected
// requests roll back every staged effect and retain that lock while recording
// their zero-effect receipt, so a response can never race a second invocation.
func beginCanvasAIRequest(w http.ResponseWriter, r *http.Request, tx *sql.Tx, project, workspace, account string, request *canvasAIRequest) (bool, error) {
	if request == nil {
		return false, nil
	}
	var board, run, action, hash string
	var status int
	var body json.RawMessage
	err := tx.QueryRowContext(r.Context(), `SELECT board_id::text,COALESCE(run_id::text,''),action,payload_hash,response_status,response_body FROM canvas_ai_requests WHERE project=$1 AND workspace_id=$2 AND account_id=$3 AND request_id=$4`, project, workspace, account, request.Key).Scan(&board, &run, &action, &hash, &status, &body)
	if err == nil {
		if board != request.Board || run != request.Run || action != request.Action || hash != request.Hash {
			reject(w, 409, "idempotency_conflict")
			return true, nil
		}
		reply(w, status, body)
		return true, nil
	}
	if err != sql.ErrNoRows {
		return false, err
	}
	var completed bool
	err = tx.QueryRowContext(r.Context(), `SELECT EXISTS(SELECT 1 FROM canvas_ai_requests WHERE project=$1 AND workspace_id=$2 AND account_id=$3 AND operation_id=$4 AND outcome='applied')`, project, workspace, account, request.Operation).Scan(&completed)
	if err != nil {
		return false, err
	}
	if completed {
		reject(w, 409, "operation_identity_conflict")
		return true, nil
	}
	_, err = tx.ExecContext(r.Context(), `SAVEPOINT canvas_ai_effects`)
	return false, err
}
func bindCanvasAIReceipt(body response, request *canvasAIRequest) {
	if request == nil {
		return
	}
	body["protocol_version"], body["request_id"], body["operation_id"], body["action"] = 2, request.Key, request.Operation, request.Action
	if request.Run != "" {
		body["run_id"] = request.Run
	}
}
func commitCanvasAIReceipt(w http.ResponseWriter, r *http.Request, tx *sql.Tx, project, workspace, account string, request *canvasAIRequest, status int, outcome string, body response) error {
	if request != nil {
		bindCanvasAIReceipt(body, request)
		raw, err := json.Marshal(body)
		if err != nil {
			return err
		}
		_, err = tx.ExecContext(r.Context(), `INSERT INTO canvas_ai_requests(project,workspace_id,account_id,request_id,board_id,run_id,action,operation_id,payload_hash,outcome,response_status,response_body) VALUES($1,$2,$3,$4,$5,NULLIF($6,'')::uuid,$7,$8,$9,$10,$11,$12)`, project, workspace, account, request.Key, request.Board, request.Run, request.Action, request.Operation, request.Hash, outcome, status, raw)
		if err != nil {
			return err
		}
	}
	if err := tx.Commit(); err != nil {
		return err
	}
	reply(w, status, body)
	return nil
}
func rejectCanvasAIRequest(w http.ResponseWriter, r *http.Request, tx *sql.Tx, project, workspace, account string, request *canvasAIRequest, status int, code string) error {
	if request == nil {
		reject(w, status, code)
		return nil
	}
	if _, err := tx.ExecContext(r.Context(), `ROLLBACK TO SAVEPOINT canvas_ai_effects`); err != nil {
		return err
	}
	return commitCanvasAIReceipt(w, r, tx, project, workspace, account, request, status, "not-applied", response{"status": "not-applied", "terminal": true, "error": code})
}