package integration

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"

	"rideaware/internal/config"
	"rideaware/internal/user"
	"rideaware/internal/workout"
)

type WahooClient struct {
	oauthService *OAuthService
	workoutRepo  *workout.Repository
	userRepo     *user.Repository
}

func NewWahooClient() *WahooClient {
	return &WahooClient{
		oauthService: NewOAuthService(),
		workoutRepo:  workout.NewRepository(),
		userRepo:     user.NewRepository(),
	}
}

// BuildAuthURL constructs the Wahoo OAuth2 authorization URL.
func (c *WahooClient) BuildAuthURL(userID uint) (string, error) {
	cfg := config.OAuth.Wahoo
	if cfg.ClientID == "" {
		return "", fmt.Errorf("Wahoo OAuth is not configured")
	}

	stateToken, err := c.oauthService.GenerateState(userID, "wahoo")
	if err != nil {
		return "", err
	}

	params := url.Values{
		"client_id":     {cfg.ClientID},
		"response_type": {"code"},
		"redirect_uri":  {cfg.RedirectURI},
		"scope":         {"workouts_write plans_write user_read offline_data"},
		"state":         {stateToken},
	}

	return cfg.AuthURL + "?" + params.Encode(), nil
}

// HandleCallback exchanges the authorization code for tokens and stores them.
func (c *WahooClient) HandleCallback(code, stateToken string) (uint, error) {
	state, err := c.oauthService.ValidateState(stateToken)
	if err != nil {
		return 0, err
	}

	if state.Provider != "wahoo" {
		return 0, fmt.Errorf("invalid state provider: expected wahoo, got %s", state.Provider)
	}

	cfg := config.OAuth.Wahoo
	params := url.Values{
		"grant_type":    {"authorization_code"},
		"code":          {code},
		"redirect_uri":  {cfg.RedirectURI},
		"client_id":     {cfg.ClientID},
		"client_secret": {cfg.ClientSecret},
	}

	tokenResp, err := c.oauthService.ExchangeCode(cfg.TokenURL, params)
	if err != nil {
		return 0, fmt.Errorf("Wahoo token exchange failed: %w", err)
	}

	if err := c.oauthService.SaveConnection(state.UserID, "wahoo", tokenResp); err != nil {
		return 0, err
	}

	return state.UserID, nil
}

// Wahoo plan JSON structures

type wahooPlanHeader struct {
	Version            string `json:"version"`
	Name               string `json:"name"`
	Description        string `json:"description"`
	WorkoutTypeFamily  string `json:"workout_type_family"`
	WorkoutTypeLocation string `json:"workout_type_location"`
	FTP                int    `json:"ftp"`
	TotalDuration      int    `json:"total_duration"`
}

type wahooPlanTarget struct {
	Type string  `json:"type"`
	Low  float64 `json:"low"`
	High float64 `json:"high"`
}

type wahooPlanInterval struct {
	Name          string            `json:"name"`
	Duration      int               `json:"duration"`
	IntensityType string            `json:"intensity_type"`
	Targets       []wahooPlanTarget `json:"targets"`
}

type wahooPlan struct {
	Header    wahooPlanHeader     `json:"header"`
	Intervals []wahooPlanInterval `json:"intervals"`
}

// PushWorkout sends a structured workout to Wahoo as a plan.
func (c *WahooClient) PushWorkout(workoutID, userID uint) error {
	accessToken, err := c.oauthService.GetValidToken(userID, "wahoo")
	if err != nil {
		return err
	}

	w, err := c.workoutRepo.GetWorkoutByID(workoutID, userID)
	if err != nil {
		return fmt.Errorf("workout not found: %w", err)
	}

	u, err := c.userRepo.GetUserByID(userID)
	if err != nil {
		return fmt.Errorf("user not found: %w", err)
	}

	ftp := 0
	if u.Profile != nil {
		ftp = u.Profile.FTP
	}

	plan := buildWahooPlan(w, ftp)

	planJSON, err := json.Marshal(plan)
	if err != nil {
		return fmt.Errorf("failed to build Wahoo plan: %w", err)
	}

	// Step 1: Create plan via Wahoo API
	planID, err := c.createWahooPlan(accessToken, planJSON, w.Title)
	if err != nil {
		return err
	}

	// Step 2: Create workout referencing the plan
	if err := c.createWahooWorkout(accessToken, planID, w); err != nil {
		return err
	}

	return nil
}

func buildWahooPlan(w *workout.Workout, ftp int) wahooPlan {
	name := w.WorkoutData.Name
	if name == "" {
		name = w.Title
	}

	plan := wahooPlan{
		Header: wahooPlanHeader{
			Version:            "1.0",
			Name:               name,
			Description:        w.Description,
			WorkoutTypeFamily:  "CYCLING",
			WorkoutTypeLocation: "INDOOR",
			FTP:                ftp,
			TotalDuration:      w.WorkoutData.TotalDuration,
		},
	}

	for _, seg := range w.WorkoutData.Segments {
		interval := segmentToWahooInterval(seg)
		plan.Intervals = append(plan.Intervals, interval)
	}

	return plan
}

func segmentToWahooInterval(seg workout.WorkoutSegment) wahooPlanInterval {
	interval := wahooPlanInterval{
		Duration: seg.Duration,
	}

	switch seg.Type {
	case "warmup":
		interval.Name = "Warm Up"
		interval.IntensityType = "WARMUP"
		if seg.PowerLow != 0 || seg.PowerHigh != 0 {
			interval.Targets = []wahooPlanTarget{{
				Type: "POWER_ZONE",
				Low:  seg.PowerLow,
				High: seg.PowerHigh,
			}}
		}
	case "steadystate":
		interval.Name = "Steady State"
		interval.IntensityType = "ACTIVE"
		if seg.Power != 0 {
			interval.Targets = []wahooPlanTarget{{
				Type: "POWER_ZONE",
				Low:  seg.Power,
				High: seg.Power,
			}}
		}
	case "interval":
		interval.Name = "Interval"
		interval.IntensityType = "ACTIVE"
		if seg.PowerLow != 0 || seg.PowerHigh != 0 {
			interval.Targets = []wahooPlanTarget{{
				Type: "POWER_ZONE",
				Low:  seg.PowerLow,
				High: seg.PowerHigh,
			}}
		}
	case "cooldown":
		interval.Name = "Cool Down"
		interval.IntensityType = "COOLDOWN"
		if seg.PowerLow != 0 || seg.PowerHigh != 0 {
			interval.Targets = []wahooPlanTarget{{
				Type: "POWER_ZONE",
				Low:  seg.PowerLow,
				High: seg.PowerHigh,
			}}
		}
	case "ramp":
		interval.Name = "Ramp"
		interval.IntensityType = "ACTIVE"
		if seg.PowerLow != 0 || seg.PowerHigh != 0 {
			interval.Targets = []wahooPlanTarget{{
				Type: "POWER_ZONE",
				Low:  seg.PowerLow,
				High: seg.PowerHigh,
			}}
		}
	case "freeride":
		interval.Name = "Free Ride"
		interval.IntensityType = "REST"
	default:
		interval.Name = seg.Type
		interval.IntensityType = "ACTIVE"
	}

	return interval
}

func (c *WahooClient) createWahooPlan(accessToken string, planJSON []byte, title string) (string, error) {
	apiURL := "https://api.wahooligan.com/v1/plans"

	body := map[string]interface{}{
		"plan": map[string]interface{}{
			"name": title,
			"file": planJSON,
		},
	}

	jsonBody, err := json.Marshal(body)
	if err != nil {
		return "", err
	}

	req, err := http.NewRequest("POST", apiURL, bytes.NewReader(jsonBody))
	if err != nil {
		return "", err
	}

	req.Header.Set("Authorization", "Bearer "+accessToken)
	req.Header.Set("Content-Type", "application/json")

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return "", fmt.Errorf("failed to create Wahoo plan: %w", err)
	}
	defer resp.Body.Close()

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}

	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
		return "", fmt.Errorf("Wahoo API returned status %d: %s", resp.StatusCode, string(respBody))
	}

	var result struct {
		ID string `json:"id"`
	}
	if err := json.Unmarshal(respBody, &result); err != nil {
		return "", fmt.Errorf("failed to parse Wahoo plan response: %w", err)
	}

	return result.ID, nil
}

func (c *WahooClient) createWahooWorkout(accessToken, planID string, w *workout.Workout) error {
	apiURL := "https://api.wahooligan.com/v1/workouts"

	body := map[string]interface{}{
		"workout": map[string]interface{}{
			"name":           w.Title,
			"plan_id":        planID,
			"workout_type":   0, // cycling
			"scheduled_date": w.ScheduledDate.Format("2006-01-02"),
		},
	}

	jsonBody, err := json.Marshal(body)
	if err != nil {
		return err
	}

	req, err := http.NewRequest("POST", apiURL, bytes.NewReader(jsonBody))
	if err != nil {
		return err
	}

	req.Header.Set("Authorization", "Bearer "+accessToken)
	req.Header.Set("Content-Type", "application/json")

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to create Wahoo workout: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
		respBody, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("Wahoo API returned status %d: %s", resp.StatusCode, string(respBody))
	}

	return nil
}