package httpapi

import (
	"context"
	"encoding/base64"
	"errors"
	"knowledge-governance/internal/dobotaiops"
	"knowledge-governance/internal/qawemail"
	"net/http"
	"time"
)

type weeklyMailStore interface {
	ReadSettings(context.Context) (qawemail.Settings, error)
	SaveSettings(context.Context, string, qawemail.SettingsInput) (qawemail.Settings, error)
	Confirm(context.Context, string, string) (qawemail.Confirmation, error)
	Unconfirm(context.Context, string) error
	ReadConfirmation(context.Context, string) (*qawemail.Confirmation, error)
	Sends(context.Context, string) ([]qawemail.Send, error)
	TestSend(context.Context, string) (string, error)
	SaveDashboardImage(context.Context, string, []byte) error
	SendDue(context.Context, time.Time) (qawemail.DueResult, error)
}

func weeklyMailError(w http.ResponseWriter, err error) {
	switch {
	case errors.Is(err, qawemail.ErrConflict):
		writeJSON(w, http.StatusConflict, map[string]string{"error": "发送设置已被其他人修改，请重新读取后再保存"})
	case errors.Is(err, qawemail.ErrInvalid):
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "发送设置无效：请检查服务器、发件地址、收件人与时间"})
	case errors.Is(err, qawemail.ErrUnavailable):
		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "周报邮件暂不可用，请稍后重试；未标记为已发送"})
	default:
		qaOpsError(w, dobotaiops.ErrUnavailable)
	}
}

func qaWeeklyMailSettings(w http.ResponseWriter, r *http.Request, c Config) {
	if !authorizeQAOps(w, r) {
		return
	}
	store, ok := c.QAWeeklyMail.(weeklyMailStore)
	if !ok {
		weeklyMailError(w, qawemail.ErrUnavailable)
		return
	}
	switch r.Method {
	case http.MethodGet:
		settings, err := store.ReadSettings(r.Context())
		if err != nil {
			weeklyMailError(w, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"data": settings})
	case http.MethodPost:
		if !authorizeQAIntent(w, r, "qa-weekly-mail") {
			return
		}
		if identity, ok := sessionFrom(r.Context()); !ok || identity.Role != "admin" {
			writeJSON(w, http.StatusForbidden, map[string]string{"error": "仅管理员可修改邮件发送设置"})
			return
		}
		var input qawemail.SettingsInput
		if decodeQualityJSON(w, r, &input) != nil {
			weeklyMailError(w, qawemail.ErrInvalid)
			return
		}
		identity, _ := sessionFrom(r.Context())
		actor := identity.Username
		settings, err := store.SaveSettings(r.Context(), actor, input)
		if err != nil {
			weeklyMailError(w, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"data": settings})
	default:
		w.Header().Set("Allow", "GET, POST")
		writeJSON(w, http.StatusMethodNotAllowed, map[string]string{"error": "不支持的方法"})
	}
}

func qaWeeklyMailConfirm(w http.ResponseWriter, r *http.Request, c Config) {
	if !authorizeQAOps(w, r) {
		return
	}
	if r.Method != http.MethodGet && !authorizeQAIntent(w, r, "qa-weekly-mail") {
		return
	}
	store, ok := c.QAWeeklyMail.(weeklyMailStore)
	if !ok {
		weeklyMailError(w, qawemail.ErrUnavailable)
		return
	}
	week := r.PathValue("week")
	switch r.Method {
	case http.MethodGet:
		confirmation, err := store.ReadConfirmation(r.Context(), week)
		if err != nil {
			weeklyMailError(w, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"data": map[string]any{"confirmation": confirmation}})
	case http.MethodPost:
		identity, _ := sessionFrom(r.Context())
		actor := identity.Username
		confirmation, err := store.Confirm(r.Context(), week, actor)
		if err != nil {
			weeklyMailError(w, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"data": map[string]any{"confirmation": confirmation}})
	case http.MethodDelete:
		if err := store.Unconfirm(r.Context(), week); err != nil {
			weeklyMailError(w, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"data": map[string]any{"confirmation": nil}})
	default:
		w.Header().Set("Allow", "GET, POST, DELETE")
		writeJSON(w, http.StatusMethodNotAllowed, map[string]string{"error": "不支持的方法"})
	}
}

func qaWeeklyMailSends(w http.ResponseWriter, r *http.Request, c Config) {
	if !authorizeQAOps(w, r) {
		return
	}
	store, ok := c.QAWeeklyMail.(weeklyMailStore)
	if !ok {
		weeklyMailError(w, qawemail.ErrUnavailable)
		return
	}
	sends, err := store.Sends(r.Context(), r.URL.Query().Get("week"))
	if err != nil {
		weeklyMailError(w, err)
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"data": map[string]any{"sends": sends}})
}

func qaWeeklyMailTest(w http.ResponseWriter, r *http.Request, c Config) {
	if !authorizeQAOps(w, r) || !authorizeQAIntent(w, r, "qa-weekly-mail") {
		return
	}
	identity, ok := sessionFrom(r.Context())
	if !ok || identity.Role != "admin" {
		writeJSON(w, http.StatusForbidden, map[string]string{"error": "仅管理员可发送测试邮件"})
		return
	}
	store, found := c.QAWeeklyMail.(weeklyMailStore)
	if !found {
		weeklyMailError(w, qawemail.ErrUnavailable)
		return
	}
	var request struct {
		Week string `json:"week"`
	}
	if decodeQualityJSON(w, r, &request) != nil {
		weeklyMailError(w, qawemail.ErrInvalid)
		return
	}
	messageID, err := store.TestSend(r.Context(), request.Week)
	if err != nil {
		if errors.Is(err, qawemail.ErrInvalid) {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "请先保存该周周报正文，并确认已配置服务器、发件人、收件人与授权码"})
			return
		}
		reason := err.Error()
		if len(reason) > 300 {
			reason = reason[:300]
		}
		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "测试发送失败：" + reason})
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"data": map[string]any{"sent": true, "week": request.Week, "message_id": messageID}})
}

func qaWeeklyMailImage(w http.ResponseWriter, r *http.Request, c Config) {
	if !authorizeQAOps(w, r) || !authorizeQAIntent(w, r, "qa-weekly-mail") {
		return
	}
	identity, ok := sessionFrom(r.Context())
	if !ok || identity.Role != "admin" {
		writeJSON(w, http.StatusForbidden, map[string]string{"error": "仅管理员可上传周报附图"})
		return
	}
	store, found := c.QAWeeklyMail.(weeklyMailStore)
	if !found {
		weeklyMailError(w, qawemail.ErrUnavailable)
		return
	}
	var request struct {
		PNGBase64 string `json:"png_base64"`
	}
	// The chart is megabytes of base64, far above the tiny quality-edit limit.
	if decodeGovernanceJSON(w, r, &request, 12<<20) != nil {
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "看板图片数据无效或过大（上限 8MB）"})
		return
	}
	png, err := base64.StdEncoding.DecodeString(request.PNGBase64)
	if err != nil || len(png) < 8 || len(png) > 8<<20 {
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "图片无效或超过 8MB"})
		return
	}
	if err := store.SaveDashboardImage(r.Context(), r.PathValue("week"), png); err != nil {
		if errors.Is(err, qawemail.ErrInvalid) {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "请先确认本周周报，再附上统计看板图片"})
			return
		}
		weeklyMailError(w, err)
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"data": map[string]any{"saved": true, "bytes": len(png)}})
}