package public

import (
	"io"
	"net/http"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"github.com/mattnite/forgejo-tickets/internal/auth"
	"github.com/mattnite/forgejo-tickets/internal/forgejo"
	"github.com/mattnite/forgejo-tickets/internal/models"
	"github.com/rs/zerolog/log"
)

type TicketHandler struct {
	deps Dependencies
}

func (h *TicketHandler) List(c *gin.Context) {
	user := auth.CurrentUser(c)

	var tickets []models.Ticket
	if err := h.deps.DB.Preload("Repo").Where("user_id = ?", user.ID).Order("created_at DESC").Limit(50).Find(&tickets).Error; err != nil {
		log.Error().Err(err).Msg("list tickets error")
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusInternalServerError, "Failed to load tickets")
		return
	}

	if len(tickets) == 0 {
		h.deps.Renderer.Render(c.Writer, c.Request, "tickets/list", map[string]interface{}{
			"Tickets": []map[string]interface{}{},
		})
		return
	}

	// Group tickets by repo
	type repoGroup struct {
		repo    models.Repo
		tickets []models.Ticket
	}
	repoMap := map[uuid.UUID]*repoGroup{}
	for _, t := range tickets {
		if _, ok := repoMap[t.RepoID]; !ok {
			repoMap[t.RepoID] = &repoGroup{repo: t.Repo}
		}
		repoMap[t.RepoID].tickets = append(repoMap[t.RepoID].tickets, t)
	}

	// Fetch issues from Forgejo per repo and build view models
	type ticketView struct {
		ID        uuid.UUID
		Title     string
		Status    string
		Priority  string
		Pinned    bool
		RepoName  string
		DueDate   *time.Time
		CreatedAt interface{}
	}
	var views []ticketView

	for _, group := range repoMap {
		issues, err := h.deps.ForgejoClient.ListIssues(group.repo.ForgejoOwner, group.repo.ForgejoRepo, "all", "")
		if err != nil {
			log.Error().Err(err).Str("repo", group.repo.Name).Msg("forgejo list issues error")
			// Show tickets with unknown status on API failure
			for _, t := range group.tickets {
				views = append(views, ticketView{
					ID:        t.ID,
					Title:     "Unable to load",
					Status:    "open",
					RepoName:  group.repo.Name,
					CreatedAt: t.CreatedAt,
				})
			}
			continue
		}

		issueByNumber := map[int64]*forgejo.Issue{}
		for i := range issues {
			issueByNumber[issues[i].Number] = &issues[i]
		}

		for _, t := range group.tickets {
			if issue, ok := issueByNumber[t.ForgejoIssueNumber]; ok {
				views = append(views, ticketView{
					ID:        t.ID,
					Title:     issue.Title,
					Status:    forgejo.DeriveStatus(issue),
					Priority:  forgejo.DerivePriority(issue),
					Pinned:    issue.PinOrder > 0,
					RepoName:  group.repo.Name,
					DueDate:   issue.DueDate,
					CreatedAt: t.CreatedAt,
				})
			}
		}
	}

	// Sort: pinned first, then by created date
	sort.SliceStable(views, func(i, j int) bool {
		if views[i].Pinned != views[j].Pinned {
			return views[i].Pinned
		}
		return false // preserve existing order for non-pinned
	})

	h.deps.Renderer.Render(c.Writer, c.Request, "tickets/list", map[string]interface{}{
		"Tickets": views,
	})
}

func (h *TicketHandler) NewForm(c *gin.Context) {
	user := auth.CurrentUser(c)

	var repos []models.Repo
	if err := h.deps.DB.
		Joins("JOIN user_repos ON user_repos.repo_id = repos.id").
		Where("user_repos.user_id = ? AND repos.active = ?", user.ID, true).
		Order("repos.name ASC").
		Find(&repos).Error; err != nil {
		log.Error().Err(err).Msg("list repos error")
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusInternalServerError, "Failed to load products")
		return
	}

	h.deps.Renderer.Render(c.Writer, c.Request, "tickets/new", map[string]interface{}{
		"Repos": repos,
	})
}

func (h *TicketHandler) Create(c *gin.Context) {
	user := auth.CurrentUser(c)

	repoID, err := uuid.Parse(c.PostForm("repo_id"))
	if err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusBadRequest, "Invalid product selection")
		return
	}

	// Validate the user has access to this repo
	var userRepo models.UserRepo
	if err := h.deps.DB.Where("user_id = ? AND repo_id = ?", user.ID, repoID).First(&userRepo).Error; err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusForbidden, "You do not have access to this project")
		return
	}

	title := c.PostForm("title")
	description := c.PostForm("description")

	if title == "" || description == "" {
		var repos []models.Repo
		h.deps.DB.
			Joins("JOIN user_repos ON user_repos.repo_id = repos.id").
			Where("user_repos.user_id = ? AND repos.active = ?", user.ID, true).
			Order("repos.name ASC").
			Find(&repos)
		h.deps.Renderer.Render(c.Writer, c.Request, "tickets/new", map[string]interface{}{
			"Repos":       repos,
			"Error":       "Title and description are required",
			"Title":       title,
			"Description": description,
			"RepoID":      repoID.String(),
		})
		return
	}

	// Look up the repo
	var repo models.Repo
	if err := h.deps.DB.First(&repo, "id = ?", repoID).Error; err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusInternalServerError, "Failed to find product")
		return
	}

	// Synchronous Forgejo issue creation
	var labelIDs []int64
	label, err := h.deps.ForgejoClient.GetLabel(repo.ForgejoOwner, repo.ForgejoRepo, "customer")
	if err != nil {
		log.Error().Err(err).Msg("forgejo get/create label error")
	} else {
		labelIDs = append(labelIDs, label.ID)
	}

	issue, err := h.deps.ForgejoClient.CreateIssue(repo.ForgejoOwner, repo.ForgejoRepo, forgejo.CreateIssueRequest{
		Title:  title,
		Body:   description + "\n\n---\n*Submitted by: " + user.Email + "*",
		Labels: labelIDs,
	})
	if err != nil {
		log.Error().Err(err).Msg("forgejo create issue error")
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusServiceUnavailable, "Service temporarily unavailable. Please try again later.")
		return
	}

	// Upload attachments if any
	form, _ := c.MultipartForm()
	if form != nil && form.File["attachments"] != nil {
		for _, fh := range form.File["attachments"] {
			f, err := fh.Open()
			if err != nil {
				log.Error().Err(err).Str("file", fh.Filename).Msg("open uploaded file error")
				continue
			}
			_, err = h.deps.ForgejoClient.CreateIssueAttachment(repo.ForgejoOwner, repo.ForgejoRepo, issue.Number, fh.Filename, f)
			f.Close()
			if err != nil {
				log.Error().Err(err).Str("file", fh.Filename).Msg("upload attachment error")
			}
		}
	}

	// Create local ticket mapping
	ticket := models.Ticket{
		UserID:             user.ID,
		RepoID:             repoID,
		ForgejoIssueNumber: issue.Number,
	}

	if err := h.deps.DB.Create(&ticket).Error; err != nil {
		log.Error().Err(err).Msg("create ticket error")
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusInternalServerError, "Failed to create ticket")
		return
	}

	c.Redirect(http.StatusSeeOther, "/tickets/"+ticket.ID.String())
}

func (h *TicketHandler) Detail(c *gin.Context) {
	user := auth.CurrentUser(c)

	ticketID, err := uuid.Parse(c.Param("id"))
	if err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusBadRequest, "Invalid ticket ID")
		return
	}

	var ticket models.Ticket
	if err := h.deps.DB.First(&ticket, "id = ?", ticketID).Error; err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusNotFound, "Ticket not found")
		return
	}

	if ticket.UserID != user.ID {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusForbidden, "Access denied")
		return
	}

	var repo models.Repo
	h.deps.DB.First(&repo, "id = ?", ticket.RepoID)

	// Fetch issue from Forgejo
	issue, err := h.deps.ForgejoClient.GetIssue(repo.ForgejoOwner, repo.ForgejoRepo, ticket.ForgejoIssueNumber)
	if err != nil {
		log.Error().Err(err).Msg("forgejo get issue error")
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusServiceUnavailable, "Unable to load ticket details. Please try again later.")
		return
	}

	// Fetch timeline instead of plain comments
	timelineEvents, err := h.deps.ForgejoClient.ListIssueTimeline(repo.ForgejoOwner, repo.ForgejoRepo, ticket.ForgejoIssueNumber)
	if err != nil {
		log.Error().Err(err).Msg("forgejo list timeline error")
		timelineEvents = nil
	}

	// Strip the "Submitted by" footer from the issue body
	cleanBody, _ := forgejo.StripCommentFooter(issue.Body)

	timeline := forgejo.BuildTimelineViews(timelineEvents, h.deps.ForgejoClient.BotLogin, false)

	// Build assignee names
	var assigneeNames []string
	for _, a := range issue.Assignees {
		assigneeNames = append(assigneeNames, a.DisplayName())
	}

	// Extract related issue references
	allText := cleanBody
	for _, tv := range timeline {
		if tv.Type == "comment" {
			allText += "\n" + tv.Body
		}
	}
	refNumbers := forgejo.ExtractIssueReferences(allText)

	// Check visibility of referenced issues
	var relatedIssues []forgejo.RelatedIssue
	if len(refNumbers) > 0 {
		// Build a set of issue numbers this customer has tickets for
		var userTickets []models.Ticket
		h.deps.DB.Where("user_id = ? AND repo_id = ?", user.ID, ticket.RepoID).Find(&userTickets)
		ticketByIssue := map[int64]models.Ticket{}
		for _, ut := range userTickets {
			ticketByIssue[ut.ForgejoIssueNumber] = ut
		}

		for _, refNum := range refNumbers {
			if refNum == ticket.ForgejoIssueNumber {
				continue // skip self-reference
			}
			ri := forgejo.RelatedIssue{Number: refNum}
			if ut, ok := ticketByIssue[refNum]; ok {
				// Customer has access to this issue
				refIssue, err := h.deps.ForgejoClient.GetIssue(repo.ForgejoOwner, repo.ForgejoRepo, refNum)
				if err == nil {
					ri.Title = refIssue.Title
					ri.IsVisible = true
					ri.DisplayText = refIssue.Title
					ri.TicketID = ut.ID.String()
				} else {
					ri.DisplayText = "[Internal Ticket]"
				}
			} else {
				ri.DisplayText = "[Internal Ticket]"
			}
			relatedIssues = append(relatedIssues, ri)
		}
	}

	h.deps.Renderer.Render(c.Writer, c.Request, "tickets/detail", map[string]interface{}{
		"Ticket": map[string]interface{}{
			"ID":          ticket.ID,
			"Title":       issue.Title,
			"Description": cleanBody,
			"Status":      forgejo.DeriveStatus(issue),
			"Priority":    forgejo.DerivePriority(issue),
			"Pinned":      issue.PinOrder > 0,
			"Assignees":   strings.Join(assigneeNames, ", "),
			"DueDate":     issue.DueDate,
			"Attachments": issue.Assets,
			"CreatedAt":   ticket.CreatedAt,
		},
		"Repo":          repo,
		"Timeline":      timeline,
		"RelatedIssues": relatedIssues,
	})
}

func (h *TicketHandler) AddComment(c *gin.Context) {
	user := auth.CurrentUser(c)

	ticketID, err := uuid.Parse(c.Param("id"))
	if err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusBadRequest, "Invalid ticket ID")
		return
	}

	var ticket models.Ticket
	if err := h.deps.DB.First(&ticket, "id = ?", ticketID).Error; err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusNotFound, "Ticket not found")
		return
	}

	if ticket.UserID != user.ID {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusForbidden, "Access denied")
		return
	}

	body := c.PostForm("body")
	if body == "" {
		c.Redirect(http.StatusSeeOther, "/tickets/"+ticket.ID.String())
		return
	}

	// Post comment directly to Forgejo
	var repo models.Repo
	if err := h.deps.DB.First(&repo, "id = ?", ticket.RepoID).Error; err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusInternalServerError, "Failed to find product")
		return
	}

	comment, err := h.deps.ForgejoClient.CreateComment(repo.ForgejoOwner, repo.ForgejoRepo, ticket.ForgejoIssueNumber, forgejo.CreateCommentRequest{
		Body: body + "\n\n---\n*Customer comment by: " + user.Email + "*",
	})
	if err != nil {
		log.Error().Err(err).Msg("forgejo create comment error")
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusServiceUnavailable, "Unable to add comment. Please try again later.")
		return
	}

	// Upload attachments to comment if any
	form, _ := c.MultipartForm()
	if form != nil && form.File["attachments"] != nil {
		for _, fh := range form.File["attachments"] {
			f, err := fh.Open()
			if err != nil {
				log.Error().Err(err).Str("file", fh.Filename).Msg("open uploaded file error")
				continue
			}
			_, err = h.deps.ForgejoClient.CreateCommentAttachment(repo.ForgejoOwner, repo.ForgejoRepo, comment.ID, fh.Filename, f)
			f.Close()
			if err != nil {
				log.Error().Err(err).Str("file", fh.Filename).Msg("upload comment attachment error")
			}
		}
	}

	c.Redirect(http.StatusSeeOther, "/tickets/"+ticket.ID.String())
}

// DownloadAttachment proxies an attachment download from Forgejo.
func (h *TicketHandler) DownloadAttachment(c *gin.Context) {
	user := auth.CurrentUser(c)

	ticketID, err := uuid.Parse(c.Param("id"))
	if err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusBadRequest, "Invalid ticket ID")
		return
	}

	var ticket models.Ticket
	if err := h.deps.DB.First(&ticket, "id = ?", ticketID).Error; err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusNotFound, "Ticket not found")
		return
	}

	if ticket.UserID != user.ID {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusForbidden, "Access denied")
		return
	}

	attachmentID := c.Param("attachmentId")
	filename := c.Param("filename")

	var repo models.Repo
	h.deps.DB.First(&repo, "id = ?", ticket.RepoID)

	// Build the Forgejo download URL
	downloadURL := h.deps.ForgejoClient.BaseURL() + "/attachments/" + attachmentID

	resp, err := h.deps.ForgejoClient.ProxyDownload(downloadURL)
	if err != nil {
		log.Error().Err(err).Msg("proxy download error")
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusBadGateway, "Failed to download file")
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		h.deps.Renderer.RenderError(c.Writer, c.Request, resp.StatusCode, "Failed to download file")
		return
	}

	// Forward content type and set download headers
	contentType := resp.Header.Get("Content-Type")
	if contentType == "" {
		contentType = "application/octet-stream"
	}
	c.Header("Content-Type", contentType)
	c.Header("Content-Disposition", "attachment; filename=\""+filename+"\"")
	if cl := resp.Header.Get("Content-Length"); cl != "" {
		c.Header("Content-Length", cl)
	}
	c.Status(http.StatusOK)
	io.Copy(c.Writer, resp.Body)
}

// GetIssueAttachment proxies an issue-level attachment download using the Forgejo asset API.
func (h *TicketHandler) GetIssueAttachment(c *gin.Context) {
	user := auth.CurrentUser(c)

	ticketID, err := uuid.Parse(c.Param("id"))
	if err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusBadRequest, "Invalid ticket ID")
		return
	}

	var ticket models.Ticket
	if err := h.deps.DB.First(&ticket, "id = ?", ticketID).Error; err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusNotFound, "Ticket not found")
		return
	}

	if ticket.UserID != user.ID {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusForbidden, "Access denied")
		return
	}

	attachmentID, err := strconv.ParseInt(c.Param("attachmentId"), 10, 64)
	if err != nil {
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusBadRequest, "Invalid attachment ID")
		return
	}
	filename := c.Param("filename")

	var repo models.Repo
	h.deps.DB.First(&repo, "id = ?", ticket.RepoID)

	// Use the Forgejo API to get the asset
	assetURL := h.deps.ForgejoClient.BaseURL() + "/api/v1/repos/" + repo.ForgejoOwner + "/" + repo.ForgejoRepo + "/issues/" + strconv.FormatInt(ticket.ForgejoIssueNumber, 10) + "/assets/" + strconv.FormatInt(attachmentID, 10)

	resp, err := h.deps.ForgejoClient.ProxyDownload(assetURL)
	if err != nil {
		log.Error().Err(err).Msg("proxy attachment download error")
		h.deps.Renderer.RenderError(c.Writer, c.Request, http.StatusBadGateway, "Failed to download file")
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		h.deps.Renderer.RenderError(c.Writer, c.Request, resp.StatusCode, "Failed to download file")
		return
	}

	contentType := resp.Header.Get("Content-Type")
	if contentType == "" {
		contentType = "application/octet-stream"
	}
	c.Header("Content-Type", contentType)
	c.Header("Content-Disposition", "attachment; filename=\""+filename+"\"")
	if cl := resp.Header.Get("Content-Length"); cl != "" {
		c.Header("Content-Length", cl)
	}
	c.Status(http.StatusOK)
	io.Copy(c.Writer, resp.Body)
}