package handlers

import (
	"encoding/json"
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"

	"git.eeqj.de/sneak/upaas/internal/middleware"
	"git.eeqj.de/sneak/upaas/internal/models"
	"git.eeqj.de/sneak/upaas/internal/service/app"
)

// apiAppResponse is the JSON representation of an app.
type apiAppResponse struct {
	ID             string `json:"id"`
	Name           string `json:"name"`
	RepoURL        string `json:"repoUrl"`
	Branch         string `json:"branch"`
	DockerfilePath string `json:"dockerfilePath"`
	Status         string `json:"status"`
	WebhookSecret  string `json:"webhookSecret"`
	SSHPublicKey   string `json:"sshPublicKey"`
	CreatedAt      string `json:"createdAt"`
	UpdatedAt      string `json:"updatedAt"`
}

// apiDeploymentResponse is the JSON representation of a deployment.
type apiDeploymentResponse struct {
	ID         int64  `json:"id"`
	AppID      string `json:"appId"`
	CommitSHA  string `json:"commitSha,omitempty"`
	Status     string `json:"status"`
	Duration   string `json:"duration,omitempty"`
	StartedAt  string `json:"startedAt"`
	FinishedAt string `json:"finishedAt,omitempty"`
}

func appToAPI(a *models.App) apiAppResponse {
	return apiAppResponse{
		ID:             a.ID,
		Name:           a.Name,
		RepoURL:        a.RepoURL,
		Branch:         a.Branch,
		DockerfilePath: a.DockerfilePath,
		Status:         string(a.Status),
		WebhookSecret:  a.WebhookSecret,
		SSHPublicKey:   a.SSHPublicKey,
		CreatedAt:      a.CreatedAt.Format("2006-01-02T15:04:05Z"),
		UpdatedAt:      a.UpdatedAt.Format("2006-01-02T15:04:05Z"),
	}
}

func deploymentToAPI(d *models.Deployment) apiDeploymentResponse {
	resp := apiDeploymentResponse{
		ID:        d.ID,
		AppID:     d.AppID,
		Status:    string(d.Status),
		Duration:  d.Duration(),
		StartedAt: d.StartedAt.Format("2006-01-02T15:04:05Z"),
	}

	if d.CommitSHA.Valid {
		resp.CommitSHA = d.CommitSHA.String
	}

	if d.FinishedAt.Valid {
		resp.FinishedAt = d.FinishedAt.Time.Format("2006-01-02T15:04:05Z")
	}

	return resp
}

// HandleAPIListApps returns a handler that lists all apps as JSON.
func (h *Handlers) HandleAPIListApps() http.HandlerFunc {
	return func(writer http.ResponseWriter, request *http.Request) {
		apps, err := h.appService.ListApps(request.Context())
		if err != nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "failed to list apps"},
				http.StatusInternalServerError)

			return
		}

		result := make([]apiAppResponse, 0, len(apps))
		for _, a := range apps {
			result = append(result, appToAPI(a))
		}

		h.respondJSON(writer, request, result, http.StatusOK)
	}
}

// HandleAPIGetApp returns a handler that gets a single app by ID.
func (h *Handlers) HandleAPIGetApp() http.HandlerFunc {
	return func(writer http.ResponseWriter, request *http.Request) {
		appID := chi.URLParam(request, "id")

		application, err := h.appService.GetApp(request.Context(), appID)
		if err != nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "internal server error"},
				http.StatusInternalServerError)

			return
		}

		if application == nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "app not found"},
				http.StatusNotFound)

			return
		}

		h.respondJSON(writer, request, appToAPI(application), http.StatusOK)
	}
}

// HandleAPICreateApp returns a handler that creates a new app.
func (h *Handlers) HandleAPICreateApp() http.HandlerFunc {
	type createRequest struct {
		Name           string `json:"name"`
		RepoURL        string `json:"repoUrl"`
		Branch         string `json:"branch"`
		DockerfilePath string `json:"dockerfilePath"`
		DockerNetwork  string `json:"dockerNetwork"`
		NtfyTopic      string `json:"ntfyTopic"`
		SlackWebhook   string `json:"slackWebhook"`
	}

	return func(writer http.ResponseWriter, request *http.Request) {
		var req createRequest

		decodeErr := json.NewDecoder(request.Body).Decode(&req)
		if decodeErr != nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "invalid JSON body"},
				http.StatusBadRequest)

			return
		}

		if req.Name == "" || req.RepoURL == "" {
			h.respondJSON(writer, request,
				map[string]string{"error": "name and repo_url are required"},
				http.StatusBadRequest)

			return
		}

		nameErr := validateAppName(req.Name)
		if nameErr != nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "invalid app name: " + nameErr.Error()},
				http.StatusBadRequest)

			return
		}

		createdApp, createErr := h.appService.CreateApp(request.Context(), app.CreateAppInput{
			Name:           req.Name,
			RepoURL:        req.RepoURL,
			Branch:         req.Branch,
			DockerfilePath: req.DockerfilePath,
			DockerNetwork:  req.DockerNetwork,
			NtfyTopic:      req.NtfyTopic,
			SlackWebhook:   req.SlackWebhook,
		})
		if createErr != nil {
			h.log.Error("api: failed to create app", "error", createErr)
			h.respondJSON(writer, request,
				map[string]string{"error": "failed to create app"},
				http.StatusInternalServerError)

			return
		}

		h.respondJSON(writer, request, appToAPI(createdApp), http.StatusCreated)
	}
}

// HandleAPIDeleteApp returns a handler that deletes an app.
func (h *Handlers) HandleAPIDeleteApp() http.HandlerFunc {
	return func(writer http.ResponseWriter, request *http.Request) {
		appID := chi.URLParam(request, "id")

		application, err := h.appService.GetApp(request.Context(), appID)
		if err != nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "internal server error"},
				http.StatusInternalServerError)

			return
		}

		if application == nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "app not found"},
				http.StatusNotFound)

			return
		}

		deleteErr := h.appService.DeleteApp(request.Context(), application)
		if deleteErr != nil {
			h.log.Error("api: failed to delete app", "error", deleteErr)
			h.respondJSON(writer, request,
				map[string]string{"error": "failed to delete app"},
				http.StatusInternalServerError)

			return
		}

		h.respondJSON(writer, request,
			map[string]string{"status": "deleted"}, http.StatusOK)
	}
}

// deploymentsPageLimit is the default number of deployments per page.
const deploymentsPageLimit = 20

// HandleAPIListDeployments returns a handler that lists deployments for an app.
func (h *Handlers) HandleAPIListDeployments() http.HandlerFunc {
	return func(writer http.ResponseWriter, request *http.Request) {
		appID := chi.URLParam(request, "id")

		application, err := h.appService.GetApp(request.Context(), appID)
		if err != nil || application == nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "app not found"},
				http.StatusNotFound)

			return
		}

		limit := deploymentsPageLimit

		if l := request.URL.Query().Get("limit"); l != "" {
			parsed, parseErr := strconv.Atoi(l)
			if parseErr == nil && parsed > 0 {
				limit = parsed
			}
		}

		deployments, deployErr := application.GetDeployments(
			request.Context(), limit,
		)
		if deployErr != nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "failed to list deployments"},
				http.StatusInternalServerError)

			return
		}

		result := make([]apiDeploymentResponse, 0, len(deployments))
		for _, d := range deployments {
			result = append(result, deploymentToAPI(d))
		}

		h.respondJSON(writer, request, result, http.StatusOK)
	}
}

// HandleAPITriggerDeploy returns a handler that triggers a deployment for an app.
func (h *Handlers) HandleAPITriggerDeploy() http.HandlerFunc {
	return func(writer http.ResponseWriter, request *http.Request) {
		appID := chi.URLParam(request, "id")

		application, err := h.appService.GetApp(request.Context(), appID)
		if err != nil || application == nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "app not found"},
				http.StatusNotFound)

			return
		}

		deployErr := h.deploy.Deploy(request.Context(), application, nil, true)
		if deployErr != nil {
			h.log.Error("api: failed to trigger deploy", "error", deployErr)
			h.respondJSON(writer, request,
				map[string]string{"error": deployErr.Error()},
				http.StatusConflict)

			return
		}

		h.respondJSON(writer, request,
			map[string]string{"status": "deploying"}, http.StatusAccepted)
	}
}

// HandleAPICreateToken returns a handler that creates an API token.
func (h *Handlers) HandleAPICreateToken() http.HandlerFunc {
	type createTokenRequest struct {
		Name string `json:"name"`
	}

	type createTokenResponse struct {
		Token string `json:"token"`
		Name  string `json:"name"`
		ID    int64  `json:"id"`
	}

	return func(writer http.ResponseWriter, request *http.Request) {
		user := middleware.APIUserFromContext(request.Context())
		if user == nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "unauthorized"},
				http.StatusUnauthorized)

			return
		}

		var req createTokenRequest

		decodeErr := json.NewDecoder(request.Body).Decode(&req)
		if decodeErr != nil {
			req.Name = "default"
		}

		if req.Name == "" {
			req.Name = "default"
		}

		rawToken, token, err := models.GenerateAPIToken(
			request.Context(), h.db, user.ID, req.Name,
		)
		if err != nil {
			h.log.Error("api: failed to create token", "error", err)
			h.respondJSON(writer, request,
				map[string]string{"error": "failed to create token"},
				http.StatusInternalServerError)

			return
		}

		h.respondJSON(writer, request, createTokenResponse{
			Token: rawToken,
			Name:  token.Name,
			ID:    token.ID,
		}, http.StatusCreated)
	}
}

// HandleAPIWhoAmI returns a handler that shows the current authenticated user.
func (h *Handlers) HandleAPIWhoAmI() http.HandlerFunc {
	type whoAmIResponse struct {
		UserID   int64  `json:"userId"`
		Username string `json:"username"`
	}

	return func(writer http.ResponseWriter, request *http.Request) {
		user := middleware.APIUserFromContext(request.Context())
		if user == nil {
			h.respondJSON(writer, request,
				map[string]string{"error": "unauthorized"},
				http.StatusUnauthorized)

			return
		}

		h.respondJSON(writer, request, whoAmIResponse{
			UserID:   user.ID,
			Username: user.Username,
		}, http.StatusOK)
	}
}