package platform

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"sort"
)

type canvasCoordinateSpace struct{ X, Y, Scale float64 }
type memberLogicalEndpoint struct{ Key, Handle string }
type memberLogicalEdge struct {
	OriginalBoard  string
	Data           map[string]any
	Source, Target memberLogicalEndpoint
}

// All documents are copied before transforming them. Each node/edge retains its
// ID; collisions in a destination reject the entire operation instead of renaming.
func moveMembersDocuments(parent, source, target string, nodeIDs []string, raw map[string]json.RawMessage) (map[string]json.RawMessage, error) {
	if source == target || source == "" || target == "" || len(nodeIDs) == 0 {
		return nil, errGraphOwnership
	}
	docs := map[string]map[string]any{}
	boards := []string{}
	for board, encoded := range raw {
		var doc map[string]any
		if err := json.Unmarshal(encoded, &doc); err != nil {
			return nil, err
		}
		docs[board] = doc
		boards = append(boards, board)
	}
	sort.Strings(boards)
	if docs[parent] == nil || docs[source] == nil || docs[target] == nil {
		return nil, errGraphOwnership
	}
	spaces := map[string]canvasCoordinateSpace{parent: {Scale: 1}}
	frames := map[string]map[string]any{}
	childForFrame := map[string]string{}
	for _, v := range docs[parent]["nodes"].([]any) {
		n := v.(map[string]any)
		data := n["data"].(map[string]any)
		sub, _ := data["subgraph"].(map[string]any)
		child, _ := sub["boardId"].(string)
		if child == "" || docs[child] == nil {
			continue
		}
		p := n["position"].(map[string]any)
		scale := float64(1)
		if presentation, ok := data["presentation"].(map[string]any); ok {
			if value, ok := presentation["contentScale"].(float64); ok {
				scale = value
			}
		}
		spaces[child] = canvasCoordinateSpace{X: p["x"].(float64) + 24, Y: p["y"].(float64) + 36, Scale: scale}
		frames[child] = n
		childForFrame[n["id"].(string)] = child
	}
	if _, ok := spaces[source]; !ok {
		return nil, errGraphOwnership
	}
	if _, ok := spaces[target]; !ok {
		return nil, errGraphOwnership
	}
	nodes := map[string]map[string]any{}
	owner := map[string]string{}
	selected := map[string]bool{}
	for _, id := range nodeIDs {
		if selected[id] {
			return nil, errGraphOwnership
		}
		selected[id] = true
	}
	for _, board := range boards {
		for _, v := range docs[board]["nodes"].([]any) {
			n := v.(map[string]any)
			key := canvasNodeKey(board, n["id"].(string))
			nodes[key] = n
			owner[key] = board
		}
	}
	for id := range selected {
		key := canvasNodeKey(source, id)
		n := nodes[key]
		if n == nil {
			return nil, errGraphOwnership
		}
		if nodes[canvasNodeKey(target, id)] != nil {
			return nil, errGraphOwnership
		}
		if targetFrame := frames[target]; targetFrame != nil && source == parent && id == targetFrame["id"] {
			return nil, errGraphOwnership
		}
		owner[key] = target
		p := n["position"].(map[string]any)
		from, to := spaces[source], spaces[target]
		p["x"] = (from.X + from.Scale*p["x"].(float64) - to.X) / to.Scale
		p["y"] = (from.Y + from.Scale*p["y"].(float64) - to.Y) / to.Scale
		delete(n["data"].(map[string]any), "frameId")
	}
	resolve := func(board, node, handle string) (memberLogicalEndpoint, error) {
		if board == parent {
			if child := childForFrame[node]; child != "" {
				data := frames[child]["data"].(map[string]any)
				ports, _ := data["ports"].([]any)
				for _, v := range ports {
					p := v.(map[string]any)
					if "port:"+p["id"].(string) == handle {
						inside := p["nodeId"].(string)
						if nodes[canvasNodeKey(child, inside)] == nil {
							return memberLogicalEndpoint{}, errGraphOwnership
						}
						h, _ := p["handle"].(string)
						return memberLogicalEndpoint{Key: canvasNodeKey(child, inside), Handle: h}, nil
					}
				}
				return memberLogicalEndpoint{}, errGraphOwnership
			}
		}
		key := canvasNodeKey(board, node)
		if nodes[key] == nil {
			return memberLogicalEndpoint{}, errGraphOwnership
		}
		return memberLogicalEndpoint{Key: key, Handle: handle}, nil
	}
	logical := []memberLogicalEdge{}
	for _, board := range boards {
		for _, v := range docs[board]["edges"].([]any) {
			e := v.(map[string]any)
			sh, _ := e["sourceHandle"].(string)
			th, _ := e["targetHandle"].(string)
			a, err := resolve(board, e["source"].(string), sh)
			if err != nil {
				return nil, err
			}
			b, err := resolve(board, e["target"].(string), th)
			if err != nil {
				return nil, err
			}
			logical = append(logical, memberLogicalEdge{OriginalBoard: board, Data: e, Source: a, Target: b})
		}
	}
	// Remove ports whose target changed ownership. Rebuild only the boundaries
	// still needed by logical edges; stable endpoint hashes deduplicate retries.
	for child, frame := range frames {
		data := frame["data"].(map[string]any)
		ports, _ := data["ports"].([]any)
		kept := []any{}
		for _, v := range ports {
			p := v.(map[string]any)
			if owner[canvasNodeKey(child, p["nodeId"].(string))] == child {
				kept = append(kept, p)
			}
		}
		data["ports"] = kept
	}
	outputNodes := map[string][]any{}
	outputEdges := map[string][]any{}
	edgeIDs := map[string]map[string]bool{}
	for _, board := range boards {
		outputNodes[board] = []any{}
		outputEdges[board] = []any{}
		edgeIDs[board] = map[string]bool{}
	}
	for _, board := range boards {
		for _, v := range docs[board]["nodes"].([]any) {
			n := v.(map[string]any)
			destination := owner[canvasNodeKey(board, n["id"].(string))]
			outputNodes[destination] = append(outputNodes[destination], n)
		}
	}
	endpoint := func(value memberLogicalEndpoint, edgeBoard, direction string) (string, string, error) {
		board := owner[value.Key]
		n := nodes[value.Key]
		node := n["id"].(string)
		if board == edgeBoard {
			return node, value.Handle, nil
		}
		frame := frames[board]
		if edgeBoard != parent || frame == nil {
			return "", "", errGraphOwnership
		}
		handle := value.Handle
		if handle == "" {
			handle = "left"
			if direction == "output" {
				handle = "right"
			}
		}
		sum := sha256.Sum256([]byte(direction + "/" + node + "/" + handle))
		id := "p-" + hex.EncodeToString(sum[:16])
		data := frame["data"].(map[string]any)
		ports := data["ports"].([]any)
		for _, v := range ports {
			p := v.(map[string]any)
			if p["nodeId"] == node && p["handle"] == handle && p["direction"] == direction {
				return frame["id"].(string), "port:" + p["id"].(string), nil
			}
		}
		data["ports"] = append(ports, map[string]any{"id": id, "nodeId": node, "handle": handle, "direction": direction})
		return frame["id"].(string), "port:" + id, nil
	}
	for _, edge := range logical {
		destination := parent
		if owner[edge.Source.Key] == owner[edge.Target.Key] {
			destination = owner[edge.Source.Key]
		}
		e := edge.Data
		id := e["id"].(string)
		if edgeIDs[destination][id] {
			return nil, errGraphOwnership
		}
		edgeIDs[destination][id] = true
		a, sh, err := endpoint(edge.Source, destination, "output")
		if err != nil {
			return nil, err
		}
		b, th, err := endpoint(edge.Target, destination, "input")
		if err != nil {
			return nil, err
		}
		e["source"] = a
		e["target"] = b
		if sh != "" {
			e["sourceHandle"] = sh
		} else {
			delete(e, "sourceHandle")
		}
		if th != "" {
			e["targetHandle"] = th
		} else {
			delete(e, "targetHandle")
		}
		from, to := spaces[edge.OriginalBoard], spaces[destination]
		projectEdgePath(e, from.Scale/to.Scale, (from.X-to.X)/to.Scale, (from.Y-to.Y)/to.Scale)
		outputEdges[destination] = append(outputEdges[destination], e)
	}
	result := map[string]json.RawMessage{}
	for _, board := range boards {
		doc := docs[board]
		doc["schema_version"] = 2
		doc["nodes"] = outputNodes[board]
		doc["edges"] = outputEdges[board]
		encoded, _ := json.Marshal(doc)
		normalized, ok := normalizeCanvas(encoded)
		if !ok {
			return nil, errGraphCapacity
		}
		result[board] = normalized
	}
	return result, nil
}