// Package webhook provides webhook handling services.
package webhook

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"log/slog"

	"go.uber.org/fx"

	"git.eeqj.de/sneak/upaas/internal/database"
	"git.eeqj.de/sneak/upaas/internal/logger"
	"git.eeqj.de/sneak/upaas/internal/models"
	"git.eeqj.de/sneak/upaas/internal/service/deploy"
)

// ServiceParams contains dependencies for Service.
type ServiceParams struct {
	fx.In

	Logger   *logger.Logger
	Database *database.Database
	Deploy   *deploy.Service
}

// Service provides webhook handling functionality.
type Service struct {
	log    *slog.Logger
	db     *database.Database
	deploy *deploy.Service
	params *ServiceParams
}

// New creates a new webhook Service.
func New(_ fx.Lifecycle, params ServiceParams) (*Service, error) {
	return &Service{
		log:    params.Logger.Get(),
		db:     params.Database,
		deploy: params.Deploy,
		params: &params,
	}, nil
}

// GiteaPushPayload represents a Gitea push webhook payload.
//
//nolint:tagliatelle // Field names match Gitea API (snake_case)
type GiteaPushPayload struct {
	Ref        string `json:"ref"`
	Before     string `json:"before"`
	After      string `json:"after"`
	CompareURL string `json:"compare_url"`
	Repository struct {
		FullName string `json:"full_name"`
		CloneURL string `json:"clone_url"`
		SSHURL   string `json:"ssh_url"`
		HTMLURL  string `json:"html_url"`
	} `json:"repository"`
	Pusher struct {
		Username string `json:"username"`
		Email    string `json:"email"`
	} `json:"pusher"`
	Commits []struct {
		ID      string `json:"id"`
		URL     string `json:"url"`
		Message string `json:"message"`
		Author  struct {
			Name  string `json:"name"`
			Email string `json:"email"`
		} `json:"author"`
	} `json:"commits"`
}

// HandleWebhook processes a webhook request.
func (svc *Service) HandleWebhook(
	ctx context.Context,
	app *models.App,
	eventType string,
	payload []byte,
) error {
	svc.log.Info("processing webhook", "app", app.Name, "event", eventType)

	// Parse payload
	var pushPayload GiteaPushPayload

	unmarshalErr := json.Unmarshal(payload, &pushPayload)
	if unmarshalErr != nil {
		svc.log.Warn("failed to parse webhook payload", "error", unmarshalErr)
		// Continue anyway to log the event
	}

	// Extract branch from ref
	branch := extractBranch(pushPayload.Ref)
	commitSHA := pushPayload.After
	commitURL := extractCommitURL(pushPayload)

	// Check if branch matches
	matched := branch == app.Branch

	// Create webhook event record
	event := models.NewWebhookEvent(svc.db)
	event.AppID = app.ID
	event.EventType = eventType
	event.Branch = branch
	event.CommitSHA = sql.NullString{String: commitSHA, Valid: commitSHA != ""}
	event.CommitURL = sql.NullString{String: commitURL, Valid: commitURL != ""}
	event.Payload = sql.NullString{String: string(payload), Valid: true}
	event.Matched = matched
	event.Processed = false

	saveErr := event.Save(ctx)
	if saveErr != nil {
		return fmt.Errorf("failed to save webhook event: %w", saveErr)
	}

	svc.log.Info("webhook event recorded",
		"app", app.Name,
		"branch", branch,
		"matched", matched,
		"commit", commitSHA,
	)

	// If branch matches, trigger deployment
	if matched {
		svc.triggerDeployment(ctx, app, event)
	}

	return nil
}

func (svc *Service) triggerDeployment(
	ctx context.Context,
	app *models.App,
	event *models.WebhookEvent,
) {
	// Capture values for goroutine
	eventID := event.ID
	appName := app.Name

	go func() {
		// Use context.WithoutCancel to ensure deployment completes
		// even if the HTTP request context is cancelled.
		deployCtx := context.WithoutCancel(ctx)

		deployErr := svc.deploy.Deploy(deployCtx, app, &eventID, true)
		if deployErr != nil {
			svc.log.Error("deployment failed", "error", deployErr, "app", appName)
		}

		// Mark event as processed
		event.Processed = true
		_ = event.Save(deployCtx)
	}()
}

// extractBranch extracts the branch name from a git ref.
func extractBranch(ref string) string {
	// refs/heads/main -> main
	const prefix = "refs/heads/"

	if len(ref) >= len(prefix) && ref[:len(prefix)] == prefix {
		return ref[len(prefix):]
	}

	return ref
}

// extractCommitURL extracts the commit URL from the webhook payload.
// Prefers the URL from the head commit, falls back to constructing from repo URL.
func extractCommitURL(payload GiteaPushPayload) string {
	// Try to find the URL from the head commit (matching After SHA)
	for _, commit := range payload.Commits {
		if commit.ID == payload.After && commit.URL != "" {
			return commit.URL
		}
	}

	// Fall back to constructing URL from repo HTML URL
	if payload.Repository.HTMLURL != "" && payload.After != "" {
		return payload.Repository.HTMLURL + "/commit/" + payload.After
	}

	return ""
}