package transport

import (
	"io"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"

	"github.com/geo-platform/tenant-api/internal/bootstrap"
	"github.com/geo-platform/tenant-api/internal/shared/response"
	"github.com/geo-platform/tenant-api/internal/tenant/app"
)

type KnowledgeHandler struct {
	svc *app.KnowledgeService
}

func NewKnowledgeHandler(a *bootstrap.App) *KnowledgeHandler {
	return &KnowledgeHandler{
		svc: app.NewKnowledgeService(
			a.DB,
			a.RetrievalProvider,
			a.VectorStore,
			a.ObjectStorage,
			a.LLM,
			a.Logger,
			a.Config.Retrieval,
			a.Config.LLM,
			a.Config.Generation.QueueSize,
			a.Config.Generation.WorkerConcurrency,
		),
	}
}

func (h *KnowledgeHandler) ListGroups(c *gin.Context) {
	data, err := h.svc.ListGroups(c.Request.Context())
	if err != nil {
		response.Error(c, err)
		return
	}
	response.Success(c, data)
}

func (h *KnowledgeHandler) CreateGroup(c *gin.Context) {
	var req app.KnowledgeGroupRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_params", err.Error()))
		return
	}

	data, err := h.svc.CreateGroup(c.Request.Context(), req)
	if err != nil {
		response.Error(c, err)
		return
	}
	response.SuccessWithStatus(c, http.StatusCreated, data)
}

func (h *KnowledgeHandler) UpdateGroup(c *gin.Context) {
	groupID, err := strconv.ParseInt(c.Param("gid"), 10, 64)
	if err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_id", "knowledge group id must be a number"))
		return
	}

	var req app.KnowledgeGroupRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_params", err.Error()))
		return
	}

	if err := h.svc.UpdateGroup(c.Request.Context(), groupID, req); err != nil {
		response.Error(c, err)
		return
	}
	response.Success(c, nil)
}

func (h *KnowledgeHandler) DeleteGroup(c *gin.Context) {
	groupID, err := strconv.ParseInt(c.Param("gid"), 10, 64)
	if err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_id", "knowledge group id must be a number"))
		return
	}

	if err := h.svc.DeleteGroup(c.Request.Context(), groupID); err != nil {
		response.Error(c, err)
		return
	}
	response.Success(c, nil)
}

func (h *KnowledgeHandler) ListItems(c *gin.Context) {
	var groupID *int64
	if raw := c.Query("group_id"); raw != "" {
		parsed, err := strconv.ParseInt(raw, 10, 64)
		if err != nil {
			response.Error(c, response.ErrBadRequest(40001, "invalid_group_id", "group id must be a number"))
			return
		}
		groupID = &parsed
	}

	data, err := h.svc.ListItems(c.Request.Context(), groupID)
	if err != nil {
		response.Error(c, err)
		return
	}
	response.Success(c, data)
}

func (h *KnowledgeHandler) GetItemDetail(c *gin.Context) {
	itemID, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_id", "knowledge item id must be a number"))
		return
	}

	data, err := h.svc.GetItemDetail(c.Request.Context(), itemID)
	if err != nil {
		response.Error(c, err)
		return
	}
	response.Success(c, data)
}

func (h *KnowledgeHandler) CreateTextItem(c *gin.Context) {
	var req app.KnowledgeTextItemRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_params", err.Error()))
		return
	}

	data, err := h.svc.CreateTextItem(c.Request.Context(), req)
	if err != nil {
		response.Error(c, err)
		return
	}
	response.SuccessWithStatus(c, http.StatusCreated, data)
}

func (h *KnowledgeHandler) CreateURLItem(c *gin.Context) {
	var req app.KnowledgeURLItemRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_params", err.Error()))
		return
	}

	data, err := h.svc.CreateURLItem(c.Request.Context(), req)
	if err != nil {
		response.Error(c, err)
		return
	}
	response.SuccessWithStatus(c, http.StatusCreated, data)
}

func (h *KnowledgeHandler) CreateFileItem(c *gin.Context) {
	groupID, err := strconv.ParseInt(c.PostForm("group_id"), 10, 64)
	if err != nil || groupID <= 0 {
		response.Error(c, response.ErrBadRequest(40001, "invalid_group_id", "group id must be a number"))
		return
	}

	name := c.PostForm("name")
	fileHeader, err := c.FormFile("file")
	if err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_file", "file is required"))
		return
	}

	file, err := fileHeader.Open()
	if err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_file", "file cannot be opened"))
		return
	}
	defer file.Close()

	content, err := io.ReadAll(file)
	if err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_file", "file cannot be read"))
		return
	}

	data, err := h.svc.CreateFileItem(c.Request.Context(), groupID, name, fileHeader.Filename, content)
	if err != nil {
		response.Error(c, err)
		return
	}
	response.SuccessWithStatus(c, http.StatusCreated, data)
}

func (h *KnowledgeHandler) DeleteItem(c *gin.Context) {
	itemID, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		response.Error(c, response.ErrBadRequest(40001, "invalid_id", "knowledge item id must be a number"))
		return
	}

	if err := h.svc.DeleteItem(c.Request.Context(), itemID); err != nil {
		response.Error(c, err)
		return
	}
	response.Success(c, nil)
}