package v1

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

	"github.com/gin-gonic/gin"

	"github.com/gochat/gochat/internal/search"
	"github.com/gochat/gochat/internal/service"
	applogger "github.com/gochat/gochat/pkg/logger"
	"github.com/gochat/gochat/pkg/pagination"
	"github.com/gochat/gochat/pkg/response"
)

// CompanyHandler handles Company CRUD + search + nested contacts/conversations/notes.
// Reference: Chatwoot app/controllers/api/v1/companies_controller.rb
type CompanyHandler struct {
	svc *service.CompanyService
}

// NewCompanyHandler creates a new CompanyHandler.
func NewCompanyHandler(svc *service.CompanyService) *CompanyHandler {
	return &CompanyHandler{svc: svc}
}

// List retrieves all companies for an account.
// GET /api/v1/accounts/:id/companies?sort=name&page=1&per_page=25
func (h *CompanyHandler) List(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	pg := parseCompanyPagination(c)
	sort := c.DefaultQuery("sort", "")

	companies, total, err := h.svc.List(c.Request.Context(), accountID, pg.Offset, pg.PerPage, sort)
	if err != nil {
		applogger.L().Errorf("List companies for account %d: %v", accountID, err)
		handleServiceError(c, err)
		return
	}

	c.JSON(http.StatusOK, companyListResponse(c.Request.Context(), h.svc.DB(), companies, total, pg.Page))
}

// Search searches companies by query.
// GET /api/v1/accounts/:id/companies/search?q=Acme&sort=name&page=1&per_page=25
func (h *CompanyHandler) Search(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	pg := parseCompanyPagination(c)
	query := c.DefaultQuery("q", "")
	if query == "" {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "Specify search string with parameter q"})
		return
	}
	sort := c.DefaultQuery("sort", "")
	searchMode := search.SearchMode(c.DefaultQuery("search_mode", "ilike"))

	companies, total, err := h.svc.Search(c.Request.Context(), accountID, query, pg.Offset, pg.PerPage, sort, searchMode)
	if err != nil {
		applogger.L().Errorf("Search companies for account %d: %v", accountID, err)
		handleServiceError(c, err)
		return
	}

	c.JSON(http.StatusOK, companyListResponse(c.Request.Context(), h.svc.DB(), companies, total, pg.Page))
}

// Get retrieves a single company by ID.
// GET /api/v1/accounts/:id/companies/:company_id
func (h *CompanyHandler) Get(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	company, svcErr := h.svc.Get(c.Request.Context(), uint(companyID), accountID)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, companyPayloadResponse(c.Request.Context(), h.svc.DB(), company))
}

// Create creates a new company.
// POST /api/v1/accounts/:id/companies
func (h *CompanyHandler) Create(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	var req service.CreateCompanyRequest
	if err := bindCompanyRequest(c, &req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	company, svcErr := h.svc.Create(c.Request.Context(), accountID, &req)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, companyPayloadResponse(c.Request.Context(), h.svc.DB(), company))
}

// Update updates an existing company.
// PUT /api/v1/accounts/:id/companies/:company_id
func (h *CompanyHandler) Update(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	var req service.UpdateCompanyRequest
	if err := bindCompanyRequest(c, &req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	company, svcErr := h.svc.Update(c.Request.Context(), uint(companyID), accountID, &req)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, companyPayloadResponse(c.Request.Context(), h.svc.DB(), company))
}

// Delete deletes a company.
// DELETE /api/v1/accounts/:id/companies/:company_id
func (h *CompanyHandler) Delete(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	if svcErr := h.svc.Delete(c.Request.Context(), uint(companyID), accountID); svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.Status(http.StatusOK)
}

func (h *CompanyHandler) DestroyCustomAttributes(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}
	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}
	var req struct {
		CustomAttributes []string `json:"custom_attributes"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if req.CustomAttributes == nil {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "custom_attributes must be an array"})
		return
	}
	company, svcErr := h.svc.DestroyCustomAttributes(c.Request.Context(), uint(companyID), accountID, req.CustomAttributes)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, companyPayloadResponse(c.Request.Context(), h.svc.DB(), company))
}

func (h *CompanyHandler) DeleteAvatar(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}
	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}
	company, svcErr := h.svc.DeleteAvatar(c.Request.Context(), uint(companyID), accountID)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, companyPayloadResponse(c.Request.Context(), h.svc.DB(), company))
}

// ListContacts retrieves contacts associated with a company.
// GET /api/v1/accounts/:id/companies/:company_id/contacts?page=1&per_page=25
func (h *CompanyHandler) ListContacts(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	pg := parseCompanyPagination(c)

	contacts, total, svcErr := h.svc.ListContacts(c.Request.Context(), uint(companyID), accountID, pg.Offset, pg.PerPage)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, companyContactsResponse(c.Request.Context(), h.svc.DB(), uint(companyID), contacts, total, pg.Page))
}

// ListConversations retrieves conversations for contacts of a company.
// GET /api/v1/accounts/:id/companies/:company_id/conversations?page=1&per_page=25
func (h *CompanyHandler) ListConversations(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	conversations, _, svcErr := h.svc.ListConversations(c.Request.Context(), uint(companyID), accountID, 0, 20)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, gin.H{"payload": serializeConversationPayloads(c.Request.Context(), h.svc.DB(), conversations)})
}

func (h *CompanyHandler) SearchContacts(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	query := c.Query("q")
	if query == "" {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "Specify search string with parameter q"})
		return
	}
	pg := parseCompanyPagination(c)
	contacts, total, svcErr := h.svc.SearchContacts(c.Request.Context(), uint(companyID), accountID, query, pg.Offset, pg.PerPage)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, companyContactsResponse(c.Request.Context(), h.svc.DB(), uint(companyID), contacts, total, pg.Page))
}

// ListNotes retrieves notes for a company.
// GET /api/v1/accounts/:id/companies/:company_id/notes?page=1&per_page=25
func (h *CompanyHandler) ListNotes(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	pg := pagination.Parse(c)

	notes, total, svcErr := h.svc.ListNotes(c.Request.Context(), uint(companyID), accountID, pg.Offset, pg.PerPage)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	_ = total
	c.JSON(http.StatusOK, companyNotesResponse(c.Request.Context(), h.svc.DB(), notes, accountID))
}

// CreateNote creates a note for a company.
// POST /api/v1/accounts/:id/companies/:company_id/notes
func (h *CompanyHandler) CreateNote(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	userID := getUserID(c)
	if userID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "user not identified")
		return
	}

	var req service.CreateCompanyNoteRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	note, svcErr := h.svc.CreateNote(c.Request.Context(), uint(companyID), accountID, userID, &req)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, gin.H{"payload": serializeCompanyNote(c.Request.Context(), h.svc.DB(), note, accountID)})
}

// DeleteNote deletes a note from a company.
// DELETE /api/v1/accounts/:id/companies/:company_id/notes/:note_id
func (h *CompanyHandler) DeleteNote(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	noteID, err := strconv.ParseUint(c.Param("note_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid note id")
		return
	}

	if err := h.svc.DeleteNote(c.Request.Context(), uint(noteID), uint(companyID), accountID); err != nil {
		handleServiceError(c, err)
		return
	}

	c.Status(http.StatusOK)
}

// AddContact adds a contact to a company.
// POST /api/v1/accounts/:id/companies/:company_id/contacts/:contact_id
func (h *CompanyHandler) AddContact(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	contactID, err := parseCompanyContactID(c)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid contact id")
		return
	}

	if err := h.svc.AddContact(c.Request.Context(), uint(companyID), accountID, uint(contactID)); err != nil {
		handleServiceError(c, err)
		return
	}

	contact, svcErr := h.svc.GetContact(c.Request.Context(), uint(companyID), accountID, contactID)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, gin.H{"payload": serializeCompanyContact(c.Request.Context(), h.svc.DB(), contact, uint(companyID))})
}

// RemoveContact removes a contact from a company.
// DELETE /api/v1/accounts/:id/companies/:company_id/contacts/:contact_id
func (h *CompanyHandler) RemoveContact(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	companyID, err := strconv.ParseUint(c.Param("company_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid company id")
		return
	}

	contactID, err := strconv.ParseUint(c.Param("contact_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid contact id")
		return
	}

	if err := h.svc.RemoveContact(c.Request.Context(), uint(companyID), accountID, uint(contactID)); err != nil {
		handleServiceError(c, err)
		return
	}

	c.Status(http.StatusOK)
}

func parseCompanyContactID(c *gin.Context) (uint, error) {
	if c.Param("contact_id") != "" {
		return parseUintParam(c, "contact_id")
	}
	var req struct {
		ContactID uint `json:"contact_id"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		return 0, err
	}
	if req.ContactID == 0 {
		return 0, strconv.ErrSyntax
	}
	return req.ContactID, nil
}

type companyRequest interface {
	*service.CreateCompanyRequest | *service.UpdateCompanyRequest
}

func parseCompanyPagination(c *gin.Context) pagination.Params {
	pg := pagination.Parse(c)
	pg.PerPage = service.CompanyResultsPerPage
	pg.Offset = (pg.Page - 1) * pg.PerPage
	return pg
}

func bindCompanyRequest[T companyRequest](c *gin.Context, req T) error {
	if !strings.HasPrefix(c.GetHeader("Content-Type"), "multipart/form-data") {
		return c.ShouldBindJSON(req)
	}
	if err := c.Request.ParseMultipartForm(32 << 20); err != nil {
		return err
	}
	name := companyFormValue(c, "name")
	description := companyFormValue(c, "description")
	websiteURL := companyFormValue(c, "website_url")
	faviconURL := companyFormValue(c, "favicon_url")
	domain := companyFormValue(c, "domain")
	if file, err := c.FormFile("company[avatar]"); err == nil && file != nil {
		faviconURL = file.Filename
	}
	customAttributes := companyFormJSON(c, "custom_attributes")

	switch r := any(req).(type) {
	case *service.CreateCompanyRequest:
		r.Name = name
		r.Description = description
		r.WebsiteURL = websiteURL
		r.FaviconURL = faviconURL
		r.Domain = domain
		r.CustomAttributes = customAttributes
	case *service.UpdateCompanyRequest:
		r.Name = name
		r.Description = description
		r.WebsiteURL = websiteURL
		r.FaviconURL = faviconURL
		r.Domain = domain
		r.CustomAttributes = customAttributes
	}
	return nil
}

func companyFormValue(c *gin.Context, key string) string {
	if value := c.PostForm("company[" + key + "]"); value != "" {
		return value
	}
	return c.PostForm(key)
}

func companyFormJSON(c *gin.Context, key string) []byte {
	if c.Request.MultipartForm == nil {
		return nil
	}
	if value := companyFormValue(c, key); value != "" {
		if json.Valid([]byte(value)) {
			return []byte(value)
		}
	}
	prefix := "company[" + key + "]["
	attrs := map[string]any{}
	for formKey, values := range c.Request.MultipartForm.Value {
		if !strings.HasPrefix(formKey, prefix) || !strings.HasSuffix(formKey, "]") || len(values) == 0 {
			continue
		}
		attrKey := strings.TrimSuffix(strings.TrimPrefix(formKey, prefix), "]")
		attrs[attrKey] = values[0]
	}
	if len(attrs) == 0 {
		return nil
	}
	data, _ := json.Marshal(attrs)
	return data
}