// Package handlers provides HTTP handlers for the rdev API.
package handlers

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"regexp"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/orchard9/rdev/internal/domain"
	"github.com/orchard9/rdev/internal/port"
	"github.com/orchard9/rdev/pkg/api"
)

// InfrastructureHandler handles git, deployment, and DNS endpoints.
type InfrastructureHandler struct {
	gitRepo  port.GitRepository
	dns      port.DNSProvider
	deployer port.Deployer
	projects port.ProjectRepository

	// Config
	defaultGitOwner string
	defaultDomain   string
	clusterIP       string
}

// projectIDRegex validates project IDs (alphanumeric, dash, underscore only).
var projectIDRegex = regexp.MustCompile(`^[a-zA-Z][a-zA-Z0-9_-]*$`)

// validateProjectID validates that a project ID is safe for use as repo/deployment name.
func validateProjectID(id string) error {
	if id == "" {
		return errors.New("project ID cannot be empty")
	}
	if len(id) > 63 { // K8s name limit
		return errors.New("project ID too long (max 63 characters)")
	}
	if !projectIDRegex.MatchString(id) {
		return errors.New("project ID must start with a letter and contain only alphanumeric characters, dashes, or underscores")
	}
	return nil
}

// InfrastructureConfig configures the infrastructure handler.
type InfrastructureConfig struct {
	// DefaultGitOwner is the default org/user for new repos (e.g., "threesix")
	DefaultGitOwner string
	// DefaultDomain is the base domain for auto-generated URLs (e.g., "threesix.ai")
	DefaultDomain string
	// ClusterIP is the external IP address for DNS records (e.g., "208.122.204.172")
	ClusterIP string
}

// NewInfrastructureHandler creates a new infrastructure handler.
func NewInfrastructureHandler(
	gitRepo port.GitRepository,
	dns port.DNSProvider,
	deployer port.Deployer,
	projects port.ProjectRepository,
	cfg InfrastructureConfig,
) *InfrastructureHandler {
	return &InfrastructureHandler{
		gitRepo:         gitRepo,
		dns:             dns,
		deployer:        deployer,
		projects:        projects,
		defaultGitOwner: cfg.DefaultGitOwner,
		defaultDomain:   cfg.DefaultDomain,
		clusterIP:       cfg.ClusterIP,
	}
}

// Mount registers the infrastructure routes.
func (h *InfrastructureHandler) Mount(r api.Router) {
	r.Route("/projects", func(r chi.Router) {
		// Git repository endpoints
		r.Post("/{id}/repo", h.CreateRepo)
		r.Get("/{id}/repo", h.GetRepo)
		r.Delete("/{id}/repo", h.DeleteRepo)

		// Deployment endpoints
		r.Post("/{id}/deploy", h.Deploy)
		r.Get("/{id}/deploy/status", h.GetDeployStatus)
		r.Delete("/{id}/deploy", h.Undeploy)
		r.Post("/{id}/deploy/restart", h.RestartDeploy)
		r.Post("/{id}/deploy/scale", h.ScaleDeploy)
		r.Get("/{id}/deploy/logs", h.GetDeployLogs)

		// Domain endpoints
		r.Post("/{id}/domain", h.AddDomain)
		r.Delete("/{id}/domain", h.RemoveDomain)
	})
}

// CreateRepoRequest is the request body for POST /projects/{id}/repo.
type CreateRepoRequest struct {
	Description string `json:"description,omitempty"`
	Private     bool   `json:"private,omitempty"`
}

// CreateRepoResponse is the response for POST /projects/{id}/repo.
type CreateRepoResponse struct {
	ID          int64  `json:"id"`
	Owner       string `json:"owner"`
	Name        string `json:"name"`
	FullName    string `json:"full_name"`
	Description string `json:"description,omitempty"`
	Private     bool   `json:"private"`
	CloneSSH    string `json:"clone_ssh"`
	CloneHTTP   string `json:"clone_http"`
	HTMLURL     string `json:"html_url"`
}

// CreateRepo creates a git repository for a project.
// POST /projects/{id}/repo
func (h *InfrastructureHandler) CreateRepo(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	// Validate project ID
	if err := validateProjectID(projectID); err != nil {
		api.WriteBadRequest(w, r, err.Error())
		return
	}

	if h.gitRepo == nil {
		api.WriteInternalError(w, r, "git repository not configured")
		return
	}

	var req CreateRepoRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil && err.Error() != "EOF" {
		api.WriteBadRequest(w, r, "invalid request body")
		return
	}

	// Create the repo
	repo, err := h.gitRepo.CreateRepo(ctx, projectID, req.Description, req.Private)
	if err != nil {
		api.WriteInternalError(w, r, fmt.Sprintf("failed to create repo: %v", err))
		return
	}

	// Note: Could update project with repo info here if we had a project repository
	// For now, just return the repo info directly
	_ = h.projects // Silence unused warning if present

	api.WriteCreated(w, r, CreateRepoResponse{
		ID:          repo.ID,
		Owner:       repo.Owner,
		Name:        repo.Name,
		FullName:    repo.FullName,
		Description: repo.Description,
		Private:     repo.Private,
		CloneSSH:    repo.CloneSSH,
		CloneHTTP:   repo.CloneHTTP,
		HTMLURL:     repo.HTMLURL,
	})
}

// GetRepo returns the git repository for a project.
// GET /projects/{id}/repo
func (h *InfrastructureHandler) GetRepo(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 10*time.Second)
	defer cancel()

	// Validate project ID
	if err := validateProjectID(projectID); err != nil {
		api.WriteBadRequest(w, r, err.Error())
		return
	}

	if h.gitRepo == nil {
		api.WriteInternalError(w, r, "git repository not configured")
		return
	}

	repo, err := h.gitRepo.GetRepo(ctx, h.defaultGitOwner, projectID)
	if err != nil {
		api.WriteNotFound(w, r, fmt.Sprintf("repo not found: %s/%s", h.defaultGitOwner, projectID))
		return
	}

	api.WriteSuccess(w, r, CreateRepoResponse{
		ID:          repo.ID,
		Owner:       repo.Owner,
		Name:        repo.Name,
		FullName:    repo.FullName,
		Description: repo.Description,
		Private:     repo.Private,
		CloneSSH:    repo.CloneSSH,
		CloneHTTP:   repo.CloneHTTP,
		HTMLURL:     repo.HTMLURL,
	})
}

// DeleteRepo deletes the git repository for a project.
// DELETE /projects/{id}/repo
func (h *InfrastructureHandler) DeleteRepo(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	// Validate project ID
	if err := validateProjectID(projectID); err != nil {
		api.WriteBadRequest(w, r, err.Error())
		return
	}

	if h.gitRepo == nil {
		api.WriteInternalError(w, r, "git repository not configured")
		return
	}

	err := h.gitRepo.DeleteRepo(ctx, h.defaultGitOwner, projectID)
	if err != nil {
		api.WriteInternalError(w, r, fmt.Sprintf("failed to delete repo: %v", err))
		return
	}

	api.WriteSuccess(w, r, map[string]string{
		"status":  "deleted",
		"project": projectID,
	})
}

// DeployRequest is the request body for POST /projects/{id}/deploy.
type DeployRequest struct {
	Image    string            `json:"image"`              // Container image
	Domain   string            `json:"domain,omitempty"`   // Custom domain (optional)
	Port     int               `json:"port,omitempty"`     // Container port (default 8080)
	Replicas int               `json:"replicas,omitempty"` // Number of replicas (default 1)
	EnvVars  map[string]string `json:"env_vars,omitempty"` // Plain environment variables
	Secrets  map[string]string `json:"secrets,omitempty"`  // Secret environment variables
}

// DeployResponse is the response for POST /projects/{id}/deploy.
type DeployResponse struct {
	ProjectName string `json:"project_name"`
	Image       string `json:"image"`
	Domain      string `json:"domain"`
	URL         string `json:"url"`
	Status      string `json:"status"`
}

// Deploy deploys a project.
// POST /projects/{id}/deploy
func (h *InfrastructureHandler) Deploy(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 60*time.Second)
	defer cancel()

	// Validate project ID
	if err := validateProjectID(projectID); err != nil {
		api.WriteBadRequest(w, r, err.Error())
		return
	}

	if h.deployer == nil {
		api.WriteInternalError(w, r, "deployer not configured")
		return
	}

	var req DeployRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		api.WriteBadRequest(w, r, "invalid request body")
		return
	}

	if req.Image == "" {
		api.WriteBadRequest(w, r, "image is required")
		return
	}

	// Build domain
	deployDomain := req.Domain
	if deployDomain == "" {
		deployDomain = projectID + "." + h.defaultDomain
	}

	// Create DNS record if DNS provider is configured
	if h.dns != nil && h.clusterIP != "" {
		_, err := h.dns.CreateRecord(ctx, domain.DNSRecord{
			Type:    "A",
			Name:    projectID,
			Content: h.clusterIP,
			TTL:     1,
			Proxied: false,
		})
		if err != nil {
			// Check if this is a "record already exists" error (not a real failure)
			// Cloudflare returns specific error codes we could check, but for now
			// we log and continue - the record might already exist from a previous deploy
			// TODO: Add proper duplicate detection once we have structured errors from adapter
			_ = err // acknowledge error - may be duplicate record which is acceptable
		}
	}

	// Deploy
	spec := domain.DeploySpec{
		ProjectName: projectID,
		Image:       req.Image,
		Domain:      deployDomain,
		Port:        req.Port,
		Replicas:    req.Replicas,
		EnvVars:     req.EnvVars,
		Secrets:     req.Secrets,
	}

	if err := h.deployer.Deploy(ctx, spec); err != nil {
		api.WriteInternalError(w, r, fmt.Sprintf("failed to deploy: %v", err))
		return
	}

	api.WriteCreated(w, r, DeployResponse{
		ProjectName: projectID,
		Image:       req.Image,
		Domain:      deployDomain,
		URL:         "https://" + deployDomain,
		Status:      "deploying",
	})
}

// GetDeployStatus returns the deployment status for a project.
// GET /projects/{id}/deploy/status
func (h *InfrastructureHandler) GetDeployStatus(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 10*time.Second)
	defer cancel()

	if h.deployer == nil {
		api.WriteInternalError(w, r, "deployer not configured")
		return
	}

	status, err := h.deployer.GetStatus(ctx, projectID)
	if err != nil {
		api.WriteInternalError(w, r, fmt.Sprintf("failed to get status: %v", err))
		return
	}

	if status == nil {
		api.WriteNotFound(w, r, fmt.Sprintf("no deployment found for project: %s", projectID))
		return
	}

	api.WriteSuccess(w, r, map[string]any{
		"project_name":   status.ProjectName,
		"image":          status.Image,
		"replicas":       status.Replicas,
		"ready_replicas": status.ReadyReplicas,
		"url":            status.URL,
		"status":         status.Status,
		"created_at":     status.CreatedAt,
		"updated_at":     status.UpdatedAt,
	})
}

// Undeploy removes the deployment for a project.
// DELETE /projects/{id}/deploy
func (h *InfrastructureHandler) Undeploy(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	if h.deployer == nil {
		api.WriteInternalError(w, r, "deployer not configured")
		return
	}

	if err := h.deployer.Undeploy(ctx, projectID); err != nil {
		api.WriteInternalError(w, r, fmt.Sprintf("failed to undeploy: %v", err))
		return
	}

	// Remove DNS record if DNS provider is configured
	if h.dns != nil {
		_ = h.dns.DeleteRecordByName(ctx, "A", projectID)
	}

	api.WriteSuccess(w, r, map[string]string{
		"status":  "undeployed",
		"project": projectID,
	})
}

// RestartDeploy restarts the deployment for a project.
// POST /projects/{id}/deploy/restart
func (h *InfrastructureHandler) RestartDeploy(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	if h.deployer == nil {
		api.WriteInternalError(w, r, "deployer not configured")
		return
	}

	if err := h.deployer.Restart(ctx, projectID); err != nil {
		api.WriteInternalError(w, r, fmt.Sprintf("failed to restart: %v", err))
		return
	}

	api.WriteSuccess(w, r, map[string]string{
		"status":  "restarting",
		"project": projectID,
	})
}

// ScaleRequest is the request body for POST /projects/{id}/deploy/scale.
type ScaleRequest struct {
	Replicas int `json:"replicas"`
}

// ScaleDeploy scales the deployment for a project.
// POST /projects/{id}/deploy/scale
func (h *InfrastructureHandler) ScaleDeploy(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	if h.deployer == nil {
		api.WriteInternalError(w, r, "deployer not configured")
		return
	}

	var req ScaleRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		api.WriteBadRequest(w, r, "invalid request body")
		return
	}

	if req.Replicas < 0 || req.Replicas > 10 {
		api.WriteBadRequest(w, r, "replicas must be between 0 and 10")
		return
	}

	if err := h.deployer.Scale(ctx, projectID, req.Replicas); err != nil {
		api.WriteInternalError(w, r, fmt.Sprintf("failed to scale: %v", err))
		return
	}

	api.WriteSuccess(w, r, map[string]any{
		"status":   "scaled",
		"project":  projectID,
		"replicas": req.Replicas,
	})
}

// GetDeployLogs returns recent logs from the deployment.
// GET /projects/{id}/deploy/logs
func (h *InfrastructureHandler) GetDeployLogs(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	if h.deployer == nil {
		api.WriteInternalError(w, r, "deployer not configured")
		return
	}

	// Default to 100 lines
	tailLines := 100

	logs, err := h.deployer.GetLogs(ctx, projectID, tailLines)
	if err != nil {
		api.WriteInternalError(w, r, fmt.Sprintf("failed to get logs: %v", err))
		return
	}

	api.WriteSuccess(w, r, map[string]string{
		"project": projectID,
		"logs":    logs,
	})
}

// AddDomainRequest is the request body for POST /projects/{id}/domain.
type AddDomainRequest struct {
	Domain string `json:"domain"` // Custom domain (e.g., "myapp.example.com")
}

// AddDomain adds a custom domain to a project.
// POST /projects/{id}/domain
func (h *InfrastructureHandler) AddDomain(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	// Validate project ID
	if err := validateProjectID(projectID); err != nil {
		api.WriteBadRequest(w, r, err.Error())
		return
	}

	var req AddDomainRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		api.WriteBadRequest(w, r, "invalid request body")
		return
	}

	if req.Domain == "" {
		api.WriteBadRequest(w, r, "domain is required")
		return
	}

	// Create DNS record if it's a threesix.ai subdomain
	if h.dns != nil && h.clusterIP != "" && isSubdomain(req.Domain, h.defaultDomain) {
		subdomain := getSubdomain(req.Domain, h.defaultDomain)
		_, err := h.dns.CreateRecord(ctx, domain.DNSRecord{
			Type:    "A",
			Name:    subdomain,
			Content: h.clusterIP,
			TTL:     1,
			Proxied: false,
		})
		if err != nil {
			api.WriteInternalError(w, r, fmt.Sprintf("failed to create DNS record: %v", err))
			return
		}
	}

	// TODO: Update ingress with new domain
	// This would require getting the current deployment and updating it

	note := "Domain configured"
	if !isSubdomain(req.Domain, h.defaultDomain) && h.clusterIP != "" {
		note = fmt.Sprintf("External domain configured. Point your DNS to %s", h.clusterIP)
	}

	api.WriteCreated(w, r, map[string]string{
		"project": projectID,
		"domain":  req.Domain,
		"status":  "configured",
		"note":    note,
	})
}

// RemoveDomain removes a custom domain from a project.
// DELETE /projects/{id}/domain
func (h *InfrastructureHandler) RemoveDomain(w http.ResponseWriter, r *http.Request) {
	projectID := chi.URLParam(r, "id")
	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	// Validate project ID
	if err := validateProjectID(projectID); err != nil {
		api.WriteBadRequest(w, r, err.Error())
		return
	}

	domainName := r.URL.Query().Get("domain")
	if domainName == "" {
		api.WriteBadRequest(w, r, "domain query parameter is required")
		return
	}

	// Delete DNS record if it's a threesix.ai subdomain
	if h.dns != nil && isSubdomain(domainName, h.defaultDomain) {
		subdomain := getSubdomain(domainName, h.defaultDomain)
		_ = h.dns.DeleteRecordByName(ctx, "A", subdomain)
	}

	// TODO: Update ingress to remove the domain

	api.WriteSuccess(w, r, map[string]string{
		"project": projectID,
		"domain":  domainName,
		"status":  "removed",
	})
}

// Helper functions

func isSubdomain(domain, baseDomain string) bool {
	suffix := "." + baseDomain
	return len(domain) > len(suffix) && domain[len(domain)-len(suffix):] == suffix
}

func getSubdomain(domain, baseDomain string) string {
	suffix := "." + baseDomain
	if len(domain) > len(suffix) && domain[len(domain)-len(suffix):] == suffix {
		return domain[:len(domain)-len(suffix)]
	}
	return domain
}