package progress

import (
	"fmt"
	"log"
	"math"
	"strings"
	"sync"
)

const (
	obrimProgressTypeCountable   = "countable"
	obrimProgressTypeUncountable = "uncountable"

	obrimProgressStateStarted   = "started"
	obrimProgressStateRunning   = "running"
	obrimProgressStateCompleted = "completed"
	obrimProgressStateCanceled  = "canceled"

	obrimProgressSuccessStarted   = "SUCCESS_PROGRESS_STARTED"
	obrimProgressSuccessRunning   = "SUCCESS_PROGRESS_RUNNING"
	obrimProgressSuccessCompleted = "SUCCESS_PROGRESS_COMPLETED"
	obrimProgressSuccessCanceled  = "SUCCESS_PROGRESS_CANCELED"

	obrimProgressFailedMisconfigured = "FAILED_PROGRESS_MISCONFIGURED"

	obrimProgressVisualWidth = 20
)

var (
	// obrimProgressMutex protects progress state transitions from corruption.
	obrimProgressMutex sync.Mutex
)

// ObrimProgressConfig defines progress configuration.
type ObrimProgressConfig struct {
	State       string `json:"state"`
	Current     int    `json:"current,omitempty"`
	Target      int    `json:"target,omitempty"`
	Placeholder string `json:"placeholder,omitempty"`
}

// ObrimProgressResponse defines standardized utility responses.
type ObrimProgressResponse struct {
	Status  bool        `json:"status"`
	Code    string      `json:"code"`
	Payload interface{} `json:"payload"`
}

// ObrimProgressCountablePayload defines countable progress payload.
type ObrimProgressCountablePayload struct {
	State      string `json:"state"`
	Current    int    `json:"current"`
	Target     int    `json:"target"`
	Percentage int    `json:"percentage"`
	Message    string `json:"message"`
	Visual     string `json:"visual"`
}

// ObrimProgressUncountablePayload defines uncountable progress payload.
type ObrimProgressUncountablePayload struct {
	State       string `json:"state"`
	Placeholder string `json:"placeholder"`
	Message     string `json:"message"`
	Visual      string `json:"visual"`
}

// ObrimProgress manages lifecycle-aware countable and uncountable progress tracking operations.
func ObrimProgress(progressType string, config ObrimProgressConfig) ObrimProgressResponse {
	obrimProgressMutex.Lock()
	defer obrimProgressMutex.Unlock()

	if err := obrimProgressValidate(progressType, config); err != nil {
		return obrimProgressBuildResponse(false, obrimProgressFailedMisconfigured, nil)
	}

	stateCode := obrimProgressHandleState(config.State)

	switch progressType {
	case obrimProgressTypeCountable:
		return obrimProgressCountable(config, stateCode)

	case obrimProgressTypeUncountable:
		return obrimProgressUncountable(config, stateCode)

	default:
		return obrimProgressBuildResponse(false, obrimProgressFailedMisconfigured, nil)
	}
}

// obrimProgressValidate validates input parameters and configuration consistency.
func obrimProgressValidate(progressType string, config ObrimProgressConfig) error {
	switch progressType {
	case obrimProgressTypeCountable:
		if config.Target <= 0 {
			return fmt.Errorf("invalid target")
		}

	case obrimProgressTypeUncountable:
		if strings.TrimSpace(config.Placeholder) == "" {
			return fmt.Errorf("missing placeholder")
		}

	default:
		return fmt.Errorf("invalid type")
	}

	switch config.State {
	case obrimProgressStateStarted,
		obrimProgressStateRunning,
		obrimProgressStateCompleted,
		obrimProgressStateCanceled:
		return nil
	default:
		return fmt.Errorf("invalid state")
	}
}

// obrimProgressHandleState processes lifecycle state transitions.
func obrimProgressHandleState(state string) string {
	switch state {
	case obrimProgressStateStarted:
		log.Printf(`{"feature":"progress","event":"started"}`)
		return obrimProgressSuccessStarted

	case obrimProgressStateRunning:
		log.Printf(`{"feature":"progress","event":"running"}`)
		return obrimProgressSuccessRunning

	case obrimProgressStateCompleted:
		log.Printf(`{"feature":"progress","event":"completed"}`)
		return obrimProgressSuccessCompleted

	case obrimProgressStateCanceled:
		log.Printf(`{"feature":"progress","event":"canceled"}`)
		return obrimProgressSuccessCanceled

	default:
		return obrimProgressFailedMisconfigured
	}
}

// obrimProgressCountable processes countable progress tracking workflows.
func obrimProgressCountable(
	config ObrimProgressConfig,
	code string,
) ObrimProgressResponse {
	percentage := obrimProgressCalculatePercentage(
		config.Current,
		config.Target,
	)

	message := obrimProgressGenerateMessage(
		obrimProgressTypeCountable,
		config.State,
		percentage,
		"",
	)

	visual := obrimProgressGenerateVisual(
		obrimProgressTypeCountable,
		percentage,
		"",
	)

	payload := ObrimProgressCountablePayload{
		State:      config.State,
		Current:    config.Current,
		Target:     config.Target,
		Percentage: percentage,
		Message:    message,
		Visual:     visual,
	}

	return obrimProgressBuildResponse(true, code, payload)
}

// obrimProgressCalculatePercentage calculates and normalizes completion percentages.
func obrimProgressCalculatePercentage(current int, target int) int {
	if current < 0 {
		return 0
	}

	if target <= 0 {
		return 0
	}

	percentage := int(
		math.Round(
			(float64(current) / float64(target)) * 100,
		),
	)

	if percentage > 100 {
		return 100
	}

	if percentage < 0 {
		return 0
	}

	return percentage
}

// obrimProgressUncountable processes uncountable progress tracking workflows.
func obrimProgressUncountable(
	config ObrimProgressConfig,
	code string,
) ObrimProgressResponse {
	placeholder := obrimProgressResolvePlaceholder(
		config.Placeholder,
	)

	message := obrimProgressGenerateMessage(
		obrimProgressTypeUncountable,
		config.State,
		0,
		placeholder,
	)

	visual := obrimProgressGenerateVisual(
		obrimProgressTypeUncountable,
		0,
		placeholder,
	)

	payload := ObrimProgressUncountablePayload{
		State:       config.State,
		Placeholder: placeholder,
		Message:     message,
		Visual:      visual,
	}

	return obrimProgressBuildResponse(true, code, payload)
}

// obrimProgressResolvePlaceholder validates and prepares placeholder activity messages.
func obrimProgressResolvePlaceholder(placeholder string) string {
	return strings.TrimSpace(placeholder)
}

// obrimProgressGenerateMessage generates human-readable progress messages.
func obrimProgressGenerateMessage(
	progressType string,
	state string,
	percentage int,
	placeholder string,
) string {
	switch progressType {
	case obrimProgressTypeCountable:
		switch state {
		case obrimProgressStateStarted:
			return fmt.Sprintf("Progress started (%d%% complete).", percentage)

		case obrimProgressStateRunning:
			return fmt.Sprintf("Progress running (%d%% complete).", percentage)

		case obrimProgressStateCompleted:
			return "Progress completed successfully."

		case obrimProgressStateCanceled:
			return "Progress canceled."
		}

	case obrimProgressTypeUncountable:
		switch state {
		case obrimProgressStateStarted:
			return fmt.Sprintf("Activity started: %s", placeholder)

		case obrimProgressStateRunning:
			return fmt.Sprintf("Activity running: %s", placeholder)

		case obrimProgressStateCompleted:
			return fmt.Sprintf("Activity completed: %s", placeholder)

		case obrimProgressStateCanceled:
			return fmt.Sprintf("Activity canceled: %s", placeholder)
		}
	}

	return ""
}

// obrimProgressGenerateVisual generates CLI-friendly visual progress representations.
func obrimProgressGenerateVisual(
	progressType string,
	percentage int,
	placeholder string,
) string {
	switch progressType {
	case obrimProgressTypeCountable:
		filled := int(
			math.Round(
				(float64(percentage) / 100.0) * obrimProgressVisualWidth,
			),
		)

		if filled > obrimProgressVisualWidth {
			filled = obrimProgressVisualWidth
		}

		if filled < 0 {
			filled = 0
		}

		return fmt.Sprintf(
			"[%s%s] %d%%",
			strings.Repeat("=", filled),
			strings.Repeat(" ", obrimProgressVisualWidth-filled),
			percentage,
		)

	case obrimProgressTypeUncountable:
		return fmt.Sprintf("[...] %s", placeholder)
	}

	return ""
}

// obrimProgressBuildResponse constructs standardized utility response payloads.
func obrimProgressBuildResponse(
	status bool,
	code string,
	payload interface{},
) ObrimProgressResponse {
	if !status {
		payload = nil
	}

	return ObrimProgressResponse{
		Status:  status,
		Code:    code,
		Payload: payload,
	}
}