package scheduler

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

	"trankilou.fr/lassistanoque/backend/internal/domain"
	"trankilou.fr/lassistanoque/backend/internal/service/task"
)

// SchedulerTool permet à l'agent de planifier des tâches pour l'utilisateur :
// exécution d'un prompt selon une spécification cron, avec ou sans répétition.
type SchedulerTool struct {
	taskService *task.Service
}

func New(taskService *task.Service) *SchedulerTool {
	return &SchedulerTool{taskService: taskService}
}

func (t *SchedulerTool) Name() string {
	return "scheduler"
}

func (t *SchedulerTool) Description() string {
	return "Schedule tasks that run automatically at specified times, with or without repetition. " +
		"Use this tool whenever the user asks to do something later or on a recurring basis " +
		"(e.g. 'every day at 8am', 'every Monday at 9am', 'tomorrow at 6pm', 'every hour'). " +
		"Actions: 'create' (schedule a new task), 'list' (list scheduled tasks), " +
		"'update' (modify a task's title, prompt, cron or repetition), " +
		"'delete' (delete a task by its id)."
}

func (t *SchedulerTool) Params() []domain.ToolParam {
	return []domain.ToolParam{}
}

func (t *SchedulerTool) Definition(ctx context.Context) *domain.ToolDefinition {
	return &domain.ToolDefinition{
		Type: "function",
		Function: &domain.ToolFunction{
			Name:        t.Name(),
			Description: t.Description(),
			Parameters: map[string]any{
				"type": "object",
				"properties": map[string]any{
					"action": map[string]any{
						"type":        "string",
						"enum":        []string{"create", "list", "update", "delete"},
						"description": "The scheduling action to perform.",
					},
					"title": map[string]any{
						"type":        "string",
						"description": "Short task title, e.g. 'Météo du matin'. Required for 'create'.",
					},
					"prompt": map[string]any{
						"type": "string",
						"description": "Self-contained prompt to execute at the scheduled time. " +
							"It will run in a fresh conversation with no memory of this one: " +
							"include all needed context. Required for 'create'.",
					},
					"cron": map[string]any{
						"type": "string",
						"description": "Cron spec, 5 fields 'minute hour day-of-month month day-of-week' " +
							"(e.g. '0 8 * * *' every day at 08:00, '0 9 * * 1' every Monday at 09:00, " +
							"'30 18 1 * *' on the 1st at 18:30) or a descriptor like '@daily', '@hourly', '@weekly'. " +
							"Required for 'create'.",
					},
					"repeat": map[string]any{
						"type": "boolean",
						"description": "true: the task repeats on schedule. " +
							"false: it runs only once, at the first time matching the cron spec, then is marked done. " +
							"Default true. Use false for one-shot requests like 'tomorrow at 8am'.",
					},
					"id": map[string]any{
						"type":        "string",
						"description": "Task id, as returned by 'list'. Required for 'update' and 'delete'.",
					},
				},
				"required": []string{"action"},
			},
		},
	}
}

func (t *SchedulerTool) Execute(ctx context.Context, input []byte, configuration string) ([]byte, error) {
	var params struct {
		Action string `json:"action"`
		Title  string `json:"title"`
		Prompt string `json:"prompt"`
		Cron   string `json:"cron"`
		Repeat *bool  `json:"repeat"`
		ID     string `json:"id"`
	}
	if err := json.Unmarshal(input, &params); err != nil {
		return nil, fmt.Errorf("invalid parameters: %w", err)
	}

	userID, ok := domain.UserIDFromContext(ctx)
	if !ok {
		return nil, fmt.Errorf("scheduler tool: missing user context")
	}
	teamID, ok := domain.TeamIDFromContext(ctx)
	if !ok {
		return nil, fmt.Errorf("scheduler tool: missing team context")
	}
	modelID, _ := domain.ModelIDFromContext(ctx)

	switch params.Action {
	case "create":
		repeat := true
		if params.Repeat != nil {
			repeat = *params.Repeat
		}
		taskModel, err := t.taskService.CreateTask(userID, teamID, &domain.Task{
			ModelID: modelID,
			Label:   params.Title,
			Prompt:  params.Prompt,
			Cron:    params.Cron,
			Repeat:  repeat,
		})
		if err != nil {
			return nil, err
		}
		result, err := json.Marshal(taskModel)
		if err != nil {
			return nil, err
		}
		return result, nil

	case "list":
		tasks, err := t.taskService.ListTasks(userID, teamID)
		if err != nil {
			return nil, err
		}
		result, err := json.Marshal(tasks)
		if err != nil {
			return nil, err
		}
		return result, nil

	case "update":
		if params.ID == "" {
			return nil, fmt.Errorf("'id' is required for action 'update'")
		}
		current, err := t.taskService.GetTask(userID, teamID, params.ID)
		if err != nil {
			return nil, err
		}
		// mise à jour partielle : seuls les champs fournis changent
		if params.Title != "" {
			current.Label = params.Title
		}
		if params.Prompt != "" {
			current.Prompt = params.Prompt
		}
		if params.Cron != "" {
			current.Cron = params.Cron
		}
		if params.Repeat != nil {
			current.Repeat = *params.Repeat
		}
		updated, err := t.taskService.UpdateTask(userID, teamID, current)
		if err != nil {
			return nil, err
		}
		result, err := json.Marshal(updated)
		if err != nil {
			return nil, err
		}
		return result, nil

	case "delete":
		if params.ID == "" {
			return nil, fmt.Errorf("'id' is required for action 'delete'")
		}
		if err := t.taskService.DeleteTask(userID, teamID, params.ID); err != nil {
			return nil, err
		}
		return []byte("task deleted"), nil

	default:
		return nil, fmt.Errorf("unknown action %q", params.Action)
	}
}