package handler

import (
	"encoding/json"
	"errors"
	"strconv"

	"gcy_hpc_server/internal/model"
	"gcy_hpc_server/internal/server"
	"gcy_hpc_server/internal/service"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
	"gorm.io/gorm"
)

type ApplicationHandler struct {
	appSvc *service.ApplicationService
	logger *zap.Logger
}

func NewApplicationHandler(appSvc *service.ApplicationService, logger *zap.Logger) *ApplicationHandler {
	return &ApplicationHandler{appSvc: appSvc, logger: logger}
}

func (h *ApplicationHandler) ListApplications(c *gin.Context) {
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
	if page < 1 {
		page = 1
	}
	if pageSize < 1 {
		pageSize = 20
	}

	apps, total, err := h.appSvc.ListApplications(c.Request.Context(), page, pageSize)
	if err != nil {
		h.logger.Error("failed to list applications", zap.Error(err))
		server.InternalError(c, err.Error())
		return
	}

	server.OK(c, gin.H{
		"applications": apps,
		"total":        total,
		"page":         page,
		"page_size":    pageSize,
	})
}

func (h *ApplicationHandler) CreateApplication(c *gin.Context) {
	var req model.CreateApplicationRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Warn("invalid request body for create application", zap.Error(err))
		server.BadRequest(c, "invalid request body")
		return
	}
	if req.Name == "" || req.ScriptTemplate == "" {
		h.logger.Warn("missing required fields for create application")
		server.BadRequest(c, "name and script_template are required")
		return
	}
	if len(req.Parameters) == 0 {
		req.Parameters = json.RawMessage(`[]`)
	}

	id, err := h.appSvc.CreateApplication(c.Request.Context(), &req)
	if err != nil {
		h.logger.Error("failed to create application", zap.Error(err))
		server.InternalError(c, err.Error())
		return
	}
	h.logger.Info("application created", zap.Int64("id", id))
	server.Created(c, gin.H{"id": id})
}

func (h *ApplicationHandler) GetApplication(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		h.logger.Warn("invalid application id", zap.String("id", c.Param("id")))
		server.BadRequest(c, "invalid id")
		return
	}
	app, err := h.appSvc.GetApplication(c.Request.Context(), id)
	if err != nil {
		h.logger.Error("failed to get application", zap.Int64("id", id), zap.Error(err))
		server.InternalError(c, err.Error())
		return
	}
	if app == nil {
		h.logger.Warn("application not found", zap.Int64("id", id))
		server.NotFound(c, "application not found")
		return
	}
	server.OK(c, app)
}

func (h *ApplicationHandler) UpdateApplication(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		h.logger.Warn("invalid application id for update", zap.String("id", c.Param("id")))
		server.BadRequest(c, "invalid id")
		return
	}
	var req model.UpdateApplicationRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Warn("invalid request body for update application", zap.Int64("id", id), zap.Error(err))
		server.BadRequest(c, "invalid request body")
		return
	}
	if err := h.appSvc.UpdateApplication(c.Request.Context(), id, &req); err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			h.logger.Warn("application not found for update", zap.Int64("id", id))
			server.NotFound(c, "application not found")
			return
		}
		h.logger.Error("failed to update application", zap.Int64("id", id), zap.Error(err))
		server.InternalError(c, "failed to update application")
		return
	}
	h.logger.Info("application updated", zap.Int64("id", id))
	server.OK(c, gin.H{"message": "application updated"})
}

func (h *ApplicationHandler) DeleteApplication(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		h.logger.Warn("invalid application id for delete", zap.String("id", c.Param("id")))
		server.BadRequest(c, "invalid id")
		return
	}
	if err := h.appSvc.DeleteApplication(c.Request.Context(), id); err != nil {
		h.logger.Error("failed to delete application", zap.Int64("id", id), zap.Error(err))
		server.InternalError(c, err.Error())
		return
	}
	h.logger.Info("application deleted", zap.Int64("id", id))
	server.OK(c, gin.H{"message": "application deleted"})
}

// [已禁用] 前端已全部迁移到 POST /tasks 接口，此端点不再使用。
/* func (h *ApplicationHandler) SubmitApplication(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		h.logger.Warn("invalid application id for submit", zap.String("id", c.Param("id")))
		server.BadRequest(c, "invalid id")
		return
	}
	var req model.ApplicationSubmitRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Warn("invalid request body for submit application", zap.Int64("id", id), zap.Error(err))
		server.BadRequest(c, "invalid request body")
		return
	}
	resp, err := h.appSvc.SubmitFromApplication(c.Request.Context(), id, req.Values)
	if err != nil {
		errStr := err.Error()
		if strings.Contains(errStr, "not found") {
			h.logger.Warn("application not found for submit", zap.Int64("id", id))
			server.NotFound(c, errStr)
			return
		}
		if strings.Contains(errStr, "validation") {
			h.logger.Warn("application submit validation failed", zap.Int64("id", id), zap.Error(err))
			server.BadRequest(c, errStr)
			return
		}
		h.logger.Error("failed to submit application", zap.Int64("id", id), zap.Error(err))
		server.InternalError(c, errStr)
		return
	}
	h.logger.Info("application submitted", zap.Int64("id", id), zap.Int32("job_id", resp.JobID))
	server.Created(c, resp)
} */