package v1

import (
	"errors"
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"

	"github.com/gochat/gochat/internal/service"
	"github.com/gochat/gochat/pkg/response"
)

// LinearIntegrationHandler handles Linear integration endpoints.
// Reference: Chatwoot Integrations::LinearController
type LinearIntegrationHandler struct {
	svc *service.LinearIntegrationService
}

// NewLinearIntegrationHandler creates a new LinearIntegrationHandler.
func NewLinearIntegrationHandler(svc *service.LinearIntegrationService) *LinearIntegrationHandler {
	return &LinearIntegrationHandler{svc: svc}
}

// Delete removes a Linear integration for an account.
// DELETE /api/v1/accounts/:account_id/integrations/linear
func (h *LinearIntegrationHandler) Delete(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

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

// GetTeams retrieves available Linear teams.
// GET /api/v1/accounts/:account_id/integrations/linear/teams
func (h *LinearIntegrationHandler) GetTeams(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	teams, svcErr := h.svc.GetTeams(c.Request.Context(), accountID)
	if svcErr != nil {
		handleLinearServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, teams)
}

// GetTeamEntities retrieves entities from a Linear team.
// GET /api/v1/accounts/:account_id/integrations/linear/team_entities
func (h *LinearIntegrationHandler) GetTeamEntities(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	entities, svcErr := h.svc.GetTeamEntities(c.Request.Context(), accountID, c.Query("team_id"))
	if svcErr != nil {
		handleLinearServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, entities)
}

// CreateIssue creates a Linear issue from a conversation.
// POST /api/v1/accounts/:account_id/integrations/linear/create_issue
func (h *LinearIntegrationHandler) CreateIssue(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

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

	result, svcErr := h.svc.CreateIssue(c.Request.Context(), accountID, req, getUserID(c))
	if svcErr != nil {
		handleLinearServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, result)
}

// LinkIssue links a Linear issue to a conversation.
// POST /api/v1/accounts/:account_id/integrations/linear/link_issue
func (h *LinearIntegrationHandler) LinkIssue(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

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

	result, svcErr := h.svc.LinkIssue(c.Request.Context(), accountID, req, getUserID(c))
	if svcErr != nil {
		handleLinearServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, result)
}

// UnlinkIssue unlinks a Linear issue from a conversation.
// POST /api/v1/accounts/:account_id/integrations/linear/unlink_issue
func (h *LinearIntegrationHandler) UnlinkIssue(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

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

	result, svcErr := h.svc.UnlinkIssue(c.Request.Context(), accountID, req, getUserID(c))
	if svcErr != nil {
		handleLinearServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, result)
}

// SearchIssue searches Linear issues.
// GET /api/v1/accounts/:account_id/integrations/linear/search_issue
func (h *LinearIntegrationHandler) SearchIssue(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	query := c.Query("q")
	if strings.TrimSpace(query) == "" {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "Specify search string with parameter q"})
		return
	}
	issues, svcErr := h.svc.SearchIssue(c.Request.Context(), accountID, query)
	if svcErr != nil {
		handleLinearServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, issues)
}

// GetLinkedIssues retrieves Linear issues linked to a conversation.
// GET /api/v1/accounts/:account_id/integrations/linear/linked_issues
func (h *LinearIntegrationHandler) GetLinkedIssues(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	conversationID, err := parseOptionalUintQueryParam(c, "conversation_id")
	if err != nil || conversationID == 0 {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid conversation_id")
		return
	}
	issues, svcErr := h.svc.GetLinkedIssues(c.Request.Context(), accountID, conversationID)
	if svcErr != nil {
		handleLinearServiceError(c, svcErr)
		return
	}
	c.JSON(http.StatusOK, issues)
}

// RegisterLinearIntegrationRoutes registers Linear integration routes.
func RegisterLinearIntegrationRoutes(g *gin.RouterGroup, h *LinearIntegrationHandler) {
	g.DELETE("/linear", h.Delete)
	linear := g.Group("/linear")
	{
		linear.DELETE("/", h.Delete)
		linear.GET("/teams", h.GetTeams)
		linear.GET("/team_entities", h.GetTeamEntities)
		linear.POST("/create_issue", h.CreateIssue)
		linear.POST("/link_issue", h.LinkIssue)
		linear.POST("/unlink_issue", h.UnlinkIssue)
		linear.GET("/search_issue", h.SearchIssue)
		linear.GET("/linked_issues", h.GetLinkedIssues)
	}
}

func handleLinearServiceError(c *gin.Context, err error) {
	var providerErr *service.LinearProviderError
	if errors.As(err, &providerErr) {
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": providerErr.Message})
		return
	}
	handleServiceError(c, err)
}