package modules

import (
	"context"
	"database/sql"
	"encoding/json"

	"github.com/heroiclabs/nakama-common/runtime"
)

// RegisterSkill 注册技能相关 RPC。
func RegisterSkill(initializer runtime.Initializer) error {
	if err := initializer.RegisterRpc("SkillService/LearnSkill", learnSkill); err != nil {
		return err
	}
	if err := initializer.RegisterRpc("SkillService/CreateJadeSlip", createJadeSlip); err != nil {
		return err
	}
	return nil
}

type learnSkillReq struct {
	CharacterID string `json:"character_id"`
	SourceType  string `json:"source_type"`
	SourceID    string `json:"source_id"`
	CustomName  string `json:"custom_name"`
}

type jadeSlipReq struct {
	CharacterID       string `json:"character_id"`
	SkillInstanceID   string `json:"skill_instance_id"`
	ConsumeProficiency bool  `json:"consume_proficiency"`
	CopyCount         int32  `json:"copy_count"`
}

type skillData struct {
	SkillInstanceID      string      `json:"skill_instance_id"`
	SkillID              string      `json:"skill_id"`
	Name                 string      `json:"name"`
	SourceTag            string      `json:"source_tag"`
	CanCopyToJadeSlip    bool        `json:"can_copy_to_jade_slip"`
	Proficiency          int32       `json:"proficiency"`
	InstanceData         interface{} `json:"instance_data"`
}

type jadeSlipItemData struct {
	InventoryID         string      `json:"inventory_id"`
	ItemID              string      `json:"item_id"`
	Name                string      `json:"name"`
	Quantity            int32       `json:"quantity"`
	InstanceData        interface{} `json:"instance_data"`
	ProficiencyConsumed int32       `json:"proficiency_consumed"`
}

func learnSkill(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error) {
	traceID := newTraceID()
	var req learnSkillReq
	if err := json.Unmarshal([]byte(payload), &req); err != nil {
		return errResp(5009, "invalid payload", traceID)
	}

	// 校验参数
	if req.SkillID == "" {
		return errResp(5010, "skill_id required", traceID)
	}

	// 查询技能信息
	var skillName, category, domain, element, alignment, damageType, scalingAttr string
	var baseTemplateJSON string
	err := db.QueryRowContext(ctx, `
		SELECT name, category, domain, element, alignment, damage_type, scaling_attr, base_template
		FROM skills WHERE id = $1
	`, req.SkillID).Scan(&skillName, &category, &domain, &element, &alignment, &damageType, &scalingAttr, &baseTemplateJSON)
	if err != nil {
		return errResp(5011, "skill not found", traceID)
	}

	// 创建技能实例
	var skillInstanceID string
	err = db.QueryRowContext(ctx, `
		INSERT INTO character_skills (
			character_id, skill_id, custom_name, instance_data,
			source_tag, proficiency, is_unique, lineage
		) VALUES ($1, $2, $3, $4, $5, 0, false, '{}')
		RETURNING id::text
	`, req.CharacterID, req.SkillID, firstNonEmpty(req.CustomName, skillName),
		baseTemplateJSON, req.SourceType).Scan(&skillInstanceID)
	if err != nil {
		logger.Error("learn skill failed: %v", err)
		return errResp(9002, "internal error", traceID)
	}

	logger.Info("SkillService/LearnSkill success: skill_instance_id=%s skill_id=%s", skillInstanceID, req.SkillID)
	return okResp(skillData{
		SkillInstanceID: skillInstanceID,
		SkillID:         req.SkillID,
		Name:            firstNonEmpty(req.CustomName, skillName),
		Category:        category,
		Domain:          domain,
		Element:         element,
		DamageType:      damageType,
		SourceTag:       req.SourceType,
	}, traceID)
}

func createJadeSlip(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error) {
	traceID := newTraceID()
	var req jadeSlipReq
	if err := json.Unmarshal([]byte(payload), &req); err != nil {
		return errResp(5014, "invalid payload", traceID)
	}

	// 查询技能信息
	var skillID, skillName, flow string
	var proficiency int32
	err := db.QueryRowContext(ctx, `
		SELECT cs.skill_id, s.name, s.flow, cs.proficiency
		FROM character_skills cs
		JOIN skills s ON cs.skill_id = s.id
		WHERE cs.id = $1 AND cs.character_id = $2
	`, req.SkillInstanceID, req.CharacterID).Scan(&skillID, &skillName, &flow, &proficiency)
	if err != nil {
		return errResp(5015, "skill not found", traceID)
	}

	// 检查是否可拓印
	if flow == "unique" || flow == "not Tradable" {
		return errResp(5016, "skill cannot be copied", traceID)
	}

	// 检查熟练度
	if proficiency < 240 {
		return errResp(5017, "insufficient proficiency", traceID)
	}

	// 创建玉简物品
	var inventoryID string
	err = db.QueryRowContext(ctx, `
		INSERT INTO inventories (character_id, item_id, slot_type, quantity, instance_data, can_trade)
		VALUES ($1, 'jade_slip', 'bag', 1, $2, true)
		RETURNING id::text
	`, req.CharacterID, fmt.Sprintf(`{"skill_id":"%s","skill_name":"%s","source_tag":"JADE_SLIP"}`, skillID, skillName)).Scan(&inventoryID)
	if err != nil {
		logger.Error("create jade slip failed: %v", err)
		return errResp(9002, "internal error", traceID)
	}

	// 消耗熟练度
	_, err = db.ExecContext(ctx, `
		UPDATE character_skills
		SET proficiency = proficiency - 240, updated_at = NOW()
		WHERE id = $1
	`, req.SkillInstanceID)
	if err != nil {
		logger.Error("consume proficiency failed: %v", err)
	}

	logger.Info("SkillService/CreateJadeSlip success: inventory_id=%s skill=%s", inventoryID, skillName)
	return okResp(jadeSlipItemData{
		InventoryID:         inventoryID,
		ItemID:              "jade_slip",
		Name:                skillName + "玉简",
		Quantity:            1,
		ProficiencyConsumed: 240,
	}, traceID)
}